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Sample records for performance static latches

  1. High performance static latches with complete single event upset immunity

    DOEpatents

    Corbett, W.T.; Weaver, H.T.

    1994-04-26

    An asymmetric response latch providing immunity to single event upset without loss of speed is described. The latch has cross-coupled inverters having a hardened logic state and a soft state, wherein the logic state of the first inverter can only be changed when the voltage on the coupling node of that inverter is low and the logic state of the second inverter can only be changed when the coupling of that inverter is high. One of more of the asymmetric response latches may be configured into a memory cell having complete immunity, which protects information rather than logic states. 5 figures.

  2. High performance static latches with complete single event upset immunity

    DOEpatents

    Corbett, Wayne T.; Weaver, Harry T.

    1994-01-01

    An asymmetric response latch providing immunity to single event upset without loss of speed. The latch has cross-coupled inverters having a hardened logic state and a soft state, wherein the logic state of the first inverter can only be changed when the voltage on the coupling node of that inverter is low and the logic state of the second inverter can only be changed when the coupling of that inverter is high. One of more of the asymmetric response latches may be configured into a memory cell having complete immunity, which protects information rather than logic states.

  3. Static latching arrangement and method

    DOEpatents

    Morrison, Larry

    1988-01-01

    A latching assembly for use in latching a cable to and unlatching it from a given object in order to move an object from one location to another is disclosed herein. This assembly includes a weighted sphere mounted to one end of a cable so as to rotate about a specific diameter of the sphere. The assembly also includes a static latch adapted for connection with the object to be moved. This latch includes an internal latching cavity for containing the sphere in a latching condition and a series of surfaces and openings which cooperate with the sphere in order to move the sphere into and out of the latching cavity and thereby connect the cable to and disconnect it from the latch without using any moving parts on the latch itself.

  4. Tendon latch

    SciTech Connect

    Watkins, B. J.

    1985-01-01

    A latch connects tendons run from a floating platform to a socket in a foundation on the sea floor. The latch includes a latch body having a plurality of dogs disposed within and urgible outward from the latch body. A piston is releasably disposed within the latch body above the dogs and moves downwardly when released to urge the dogs outwardly from the body into latching engagement with the socket. A trigger mechanism in the latch releases the piston when the latch body lands in the socket and contacts a trigger pin projecting upwardly from the bottom of the socket. A series of wedges are disposed exteriorally on the body and inhibit lateral movement of the body relative to the socket when the tendon is subjected to a cycle bending loads.

  5. Rotary latch

    NASA Technical Reports Server (NTRS)

    Kramer, Joel M. (Inventor)

    1995-01-01

    A rotary latch is disclosed, including a hollow, cylindrical outer member and a concentrically arranged inner rotor. The rotor is rotatable within the outer cylindrical member. The outer cylindrical member includes a pair of aligned openings as a cylinder first end facing a latch pin. The rotor includes a pair of aligned slots at a rotor first end facing the latch pin. Slot extensions are provided in the rotor, the slot extensions extending generally perpendicularly to the slots and generally parallel to the rotor first end. In a first position, the outer cylindrical member openings and the rotor slots are aligned to allow receipt of the latch pin. In a second position, the openings and the slot extensions are aligned thereby engaging the latch pin within a closed area defined by the rotor slot extensions and the outer cylinder openings.

  6. Strong-back safety latch

    SciTech Connect

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  7. Latch assembly

    DOEpatents

    Frederickson, J.R.; Harper, W.H.; Perez, R.

    1984-08-17

    A latch assembly for releasably securing an article in the form of a canister within a container housing. The assembly includes a cam pivotally mounted on the housing wall and biased into the housing interior. The cam is urged into a disabled position by the canister as it enters the housing and a latch release plate maintains the cam disabled when the canister is properly seated in the housing. Upon displacement of the release plate, the cam snaps into latching engagement against the canister for securing the same within the housing. 2 figs.

  8. Latch assembly

    SciTech Connect

    Frederickson, James R.; Harper, William H.; Perez, Raymond

    1986-01-01

    A latch assembly for releasably securing an article in the form of a canister within a container housing. The assembly includes a cam pivotally mounted on the housing wall and biased into the housing interior. The cam is urged into a disabled position by the canister as it enters the housing and a latch release plate maintains the cam disabled when the canister is properly seated in the housing. Upon displacement of the release plate, the cam snaps into latching engagement against the canister for securing the same within the housing.

  9. Rotary mechanical latch

    DOEpatents

    Spletzer, Barry L.; Martinez, Michael A.; Marron, Lisa C.

    2012-11-13

    A rotary mechanical latch for positive latching and unlatching of a rotary device with a latchable rotating assembly having a latching gear that can be driven to latched and unlatched states by a drive mechanism such as an electric motor. A cam arm affixed to the latching gear interfaces with leading and trailing latch cams affixed to a flange within the drive mechanism. The interaction of the cam arm with leading and trailing latch cams prevents rotation of the rotating assembly by external forces such as those due to vibration or tampering.

  10. Load regulating latch

    NASA Technical Reports Server (NTRS)

    Appleberry, W. T. (Inventor)

    1977-01-01

    A load regulating mechanical latch is described that has a pivotally mounted latch element having a hook-shaped end with a strike roller-engaging laterally open hook for engaging a stationary strike roller. The latch element or hook is pivotally mounted in a clevis end of an elongated latch stem that is adapted for axial movement through an opening in a support plate or bracket mounted to a structural member. A coil spring is disposed over and around the extending latch stem and the lower end of the coil spring engages the support bracket. A thrust washer is removably attached to the other end of the latch stem and engages the other end of the coil spring and compresses the coil spring thereby preloading the spring and the latch element carried by the latch stem. The hook-shaped latch element has a limited degree of axial travel for loading caused by structural distortion which may change the relative positions of the latch element hook and the strike roller. Means are also provided to permit limited tilt of the latch element due to loading of the hook.

  11. Preloadable vector sensitive latch

    NASA Technical Reports Server (NTRS)

    Acres, William R. (Inventor)

    1987-01-01

    A preloadable vector-sensitive latch which automatically releases when the force vector from a latch memebr reaches a specified release angle is presented. In addition, it contains means to remove clearance between the latched members and to preload the latch to prevent separation at angles less than the specified release angle. The latch comprises a triangular main link, a free link connected between a first corner of the main link and a yoke member, a housing, and an actuator connected between the yoke member and the housing. A return spring bias means connects the main link to a portion of the housing. A second corner of the main link is slidably and pivotally connected to the housing via a slot in a web portion of the housing. The latch housing has a rigid docking ring alignable with a mating locking ring which is engageable by a locking roller journalled on the third corner of the triangular main link.

  12. Steam separator latch assembly

    DOEpatents

    Challberg, R.C.; Kobsa, I.R.

    1994-02-01

    A latch assembly removably joins a steam separator assembly to a support flange disposed at a top end of a tubular shroud in a nuclear reactor pressure vessel. The assembly includes an annular head having a central portion for supporting the steam separator assembly thereon, and an annular head flange extending around a perimeter thereof for supporting the head to the support flange. A plurality of latches are circumferentially spaced apart around the head flange with each latch having a top end, a latch hook at a bottom end thereof, and a pivot support disposed at an intermediate portion therebetween and pivotally joined to the head flange. The latches are pivoted about the pivot supports for selectively engaging and disengaging the latch hooks with the support flange for fixedly joining the head to the shroud or for allowing removal thereof. 12 figures.

  13. Steam separator latch assembly

    DOEpatents

    Challberg, Roy C.; Kobsa, Irvin R.

    1994-01-01

    A latch assembly removably joins a steam separator assembly to a support flange disposed at a top end of a tubular shroud in a nuclear reactor pressure vessel. The assembly includes an annular head having a central portion for supporting the steam separator assembly thereon, and an annular head flange extending around a perimeter thereof for supporting the head to the support flange. A plurality of latches are circumferentially spaced apart around the head flange with each latch having a top end, a latch hook at a bottom end thereof, and a pivot support disposed at an intermediate portion therebetween and pivotally joined to the head flange. The latches are pivoted about the pivot supports for selectively engaging and disengaging the latch hooks with the support flange for fixedly joining the head to the shroud or for allowing removal thereof.

  14. Latching relay switch assembly

    DOEpatents

    Duimstra, Frederick A.

    1991-01-01

    A latching relay switch assembly which includes a coil section and a switch or contact section. The coil section includes at least one permanent magnet and at least one electromagnet. The respective sections are, generally, arranged in separate locations or cavities in the assembly. The switch is latched by a permanent magnet assembly and selectively switched by an overriding electromagnetic assembly.

  15. Self indexing latch system

    NASA Technical Reports Server (NTRS)

    Gibson, John C. (Inventor); Calvert, John A. (Inventor); Nesmith, Malcolm F. (Inventor); Cloyd, Richard A. (Inventor)

    1986-01-01

    A self-latching jaw assembly is described which includes a pair of jaws for latching a fitting of an associated structure such as the keel fitting of a space telescope. The jaw assembly automatically locates the fitting received on a positioning pedestal and latches it in its original location on the pedestal without need of precision alignment. The first jaw is actuated and moved to the right whereupon a reciprocating plunger, extended from the nose of the jaw senses the hub of the spool. A jaw position responsive switch is then actuated to terminate the drive motor of the jaw. The astronaut will then actuate the drive motor of the jaw and the jaw will move to the left, whereupon the standoff will engage the face of the jaw in a latching position. In the latching position, the noses of the jaws will be under the flanges of the spool.

  16. Safety rod latch inspection

    SciTech Connect

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small button'' in the latch mechanism had broken off of the lock plunger'' and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  17. Safety rod latch inspection

    SciTech Connect

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small ``button`` in the latch mechanism had broken off of the ``lock plunger`` and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  18. Optical data latch

    SciTech Connect

    Vawter, G. Allen

    2010-08-31

    An optical data latch is formed on a substrate from a pair of optical logic gates in a cross-coupled arrangement in which optical waveguides are used to couple an output of each gate to an photodetector input of the other gate. This provides an optical bi-stability which can be used to store a bit of optical information in the latch. Each optical logic gate, which can be an optical NOT gate (i.e. an optical inverter) or an optical NOR gate, includes a waveguide photodetector electrically connected in series with a waveguide electroabsorption modulator. The optical data latch can be formed on a III-V compound semiconductor substrate (e.g. an InP or GaAs substrate) from III-V compound semiconductor layers. A number of optical data latches can be cascaded to form a clocked optical data shift register.

  19. Design, testing and evaluation of latching end effector

    NASA Technical Reports Server (NTRS)

    Walker, B.; Vandersluis, R.

    1995-01-01

    The Latching End Effector (LEE) forms part of the Space Station Remote Manipulator System (SSRMS) for which Spar Aerospace Ltd, Space Systems Division is the prime contractor. The design, testing and performance evaluation of the Latching End Effector mechanisms is the subject of this paper focusing on: (1) ambient, thermal and vibration testing; (2) snare/rigidize performance testing and interaction during payload acquisition; and (3) latch/umbilical test results and performance.

  20. Rectifier cabinet static breaker

    DOEpatents

    Costantino, Jr, Roger A.; Gliebe, Ronald J.

    1992-09-01

    A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload.

  1. Rectifier cabinet static breaker

    SciTech Connect

    Costantino, R.A. Jr; Gliebe, R.J.

    1992-09-01

    A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload. 7 figs.

  2. J-hook latching device

    NASA Technical Reports Server (NTRS)

    Milam, Malcolm B. (Inventor)

    1992-01-01

    Described here is a latching device for latching two items together that has a housing and a shaft mounted to one item such that rotation of the shaft by a sprocket causes the shaft to move longitudinally up and down. The shaft has one end extending beyond the housing with an alignment cone attached to this end for engaging a receptor on the other item. A latch mounted to a shaft by a traveling nut provides a pivot point for the latch so that rotation of the shaft causes the pivot point of the latch to translate along the longitudinal axis of the shaft. Camming surfaces and a camming spring are used for rotating the latch so that the latch will engage and disengage a receptor on the other item.

  3. An SEU-hardened CMOS data latch design

    SciTech Connect

    Rockett, L.R. Jr.

    1988-12-01

    A Single Event Upset (SEU)-hardened Complementary Metal-Oxide Semiconductor (CMOS) data latch design is described. The hardness is achieved by virtue of the latch design, thus no fabrication process or design groundrule development is required. Hardness is gained with comparatively little adverse impact on performance. Cyclotron tests provided hardness verification.

  4. Magnetic latching solenoid

    DOEpatents

    Marts, Donna J.; Richardson, John G.; Albano, Richard K.; Morrison, Jr., John L.

    1995-01-01

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.

  5. Magnetic latching solenoid

    DOEpatents

    Marts, D.J.; Richardson, J.G.; Albano, R.K.; Morrison, J.L. Jr.

    1995-11-28

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized. 2 figs.

  6. Hatch latch mechanism for Spacelab scientific airlock

    NASA Technical Reports Server (NTRS)

    Terhaar, G. R.

    1979-01-01

    The requirements, design tradeoff, design, and performance of the Spacelab scientific airlock hatch latching mechanisms are described. At space side the hatch is closed and held against internal airlock/module pressure by 12 tangential overcenter hooks driven by a driver. At module side the hatch is held by 4 hooks driven by rollers running on a cammed driver.

  7. Latching micro optical switch

    DOEpatents

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  8. Minimal Power Latch for Single-Slope ADCs

    NASA Technical Reports Server (NTRS)

    Hancock, Bruce R.

    2013-01-01

    positive- true signals and is implemented using AND-OR-INVERT logic. In this implementation, both latches are cleared when the comparator is reset. Two redundant transistors are removed from the reset side of each latch, making for a compact layout. CMOS imagers with column-parallel ADCs have demonstrated high performance for remote sensing applications. With this latch circuit, the power consumption and noise can be further reduced. This innovation can be used in CMOS imagers and very-low-power electronics

  9. Miniature Latching Valve

    NASA Technical Reports Server (NTRS)

    Johnson, A. David; Benson, Glendon M.

    2008-01-01

    A miniature latching valve has been invented to satisfy a need for an electrically controllable on/off pneumatic valve that is lightweight and compact and remains in the most recently commanded open or closed state when power is not supplied. The valve includes a poppet that is moved into or out of contact with a seat to effect closure or opening, respectively, of the flow path. Motion of the poppet is initiated by electrical heating of one of two opposing pairs of nickel/titanium shape-memory alloy (SMA) wires above their transition temperature: heated wires contract to their remembered length, applying tension to pull the poppet toward or away from the seat. A latch consisting mainly of a bistable Belleville washer (a conical spring) made of a hardened stainless steel operates between two stable positions corresponding to the fully closed or fully open state, holding the poppet in one of these positions when power is not applied to either pair of SMA wires. To obtain maximum actuation force and displacement, the SMA wires must be kept in tension. The mounting fixtures at the ends of the wires must support large tensile stresses without creating stress concentrations that would limit the fatigue lives of the wires. An earlier design provided for each wire to be crimped in a conical opening with a conical steel ferrule that was swaged into the opening to produce a large, uniformly distributed holding force. In a subsequent design, the conical ferrule was replaced with a larger crimped cylindrical ferrule depicted in the figure. A major problem in designing the valve was to protect the SMA wires from a bake-out temperature of 300 C. The problem was solved by incorporating the SMA wires into an actuator module that is inserted into a barrel of the valve body and is held in place by miniature clip rings.

  10. Performance tradeoffs in static and dynamic load balancing strategies

    NASA Technical Reports Server (NTRS)

    Iqbal, M. A.; Saltz, J. H.; Bokhart, S. H.

    1986-01-01

    The problem of uniformly distributing the load of a parallel program over a multiprocessor system was considered. A program was analyzed whose structure permits the computation of the optimal static solution. Then four strategies for load balancing were described and their performance compared. The strategies are: (1) the optimal static assignment algorithm which is guaranteed to yield the best static solution, (2) the static binary dissection method which is very fast but sub-optimal, (3) the greedy algorithm, a static fully polynomial time approximation scheme, which estimates the optimal solution to arbitrary accuracy, and (4) the predictive dynamic load balancing heuristic which uses information on the precedence relationships within the program and outperforms any of the static methods. It is also shown that the overhead incurred by the dynamic heuristic is reduced considerably if it is started off with a static assignment provided by either of the other three strategies.

  11. ROPS performance during field upset and static testing.

    PubMed

    Harris, J R; McKenzie, E A; Etherton, J R; Cantis, D M; Ronaghi, M

    2010-01-01

    Agriculture remains one of the most hazardous occupations in the U.S. By conservative estimates, tractor overturns alone claim 120 lives annually. A rollover protective structure (ROPS) and a seatbelt are a highly effective engineering safety control that can prevent many of these fatalities and reduce the severity of injuries associated with tractor overturn. SAE J2194 is a consensus performance standard established for agricultural ROPS. According to this standard, satisfactory ROPS performance can be demonstrated through static testing, field upset testing, or impact testing. A previous modeling study suggested that static testing may underpredict the strain induced in a ROPS during afield upset. In the current study, field upset testing and laboratory static testing results were compared. Field upset testing included six rear and six side upset tests performed according to SAE J2194 guidelines. Additionally, static testing was performed on a ROPS of the same model. The results support findings from the modeling study. Near the lowest sections of the ROPS, the plastic strain resulting from rear upset testing exceeded the plastic strain from static testing for 18 of 24 data points. Conversely, the ROPS plastic strain from side upset testing was typically less than plastic strain from laboratory static testing. However, data indicate that the side upset test may not be very repeatable. This study suggests that the longitudinal loading energy criterion for static testing might not be a conservative predictor of rear upset ROPS response. PMID:20222267

  12. K-Band Latching Switches

    NASA Technical Reports Server (NTRS)

    Piotrowski, W. S.; Raue, J. E.

    1984-01-01

    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  13. Retaining latch for a water pit gate

    DOEpatents

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  14. Optical set-reset latch

    DOEpatents

    Skogen, Erik J.

    2013-01-29

    An optical set-reset (SR) latch is formed from a first electroabsorption modulator (EAM), a second EAM and a waveguide photodetector (PD) which are arranged in an optical and electrical feedback loop which controls the transmission of light through the first EAM to latch the first EAM in a light-transmissive state in response to a Set light input. A second waveguide PD controls the transmission of light through the second EAM and is used to switch the first EAM to a light-absorptive state in response to a Reset light input provided to the second waveguide PD. The optical SR latch, which may be formed on a III-V compound semiconductor substrate (e.g. an InP or a GaAs substrate) as a photonic integrated circuit (PIC), stores a bit of optical information and has an optical output for the logic state of that bit of information.

  15. Electrical latching of microelectromechanical devices

    DOEpatents

    Garcia, Ernest J.; Sleefe, Gerard E.

    2004-11-02

    Methods are disclosed for row and column addressing of an array of microelectromechanical (MEM) devices. The methods of the present invention are applicable to MEM micromirrors or memory elements and allow the MEM array to be programmed and maintained latched in a programmed state with a voltage that is generally lower than the voltage required for electrostatically switching the MEM devices.

  16. Performance analysis of static locking in distributed database systems

    SciTech Connect

    Shyu, S.C. ); Li, V.O.K. . Dept. of Electrical Engineering)

    1990-06-01

    Numerous performance models have been proposed for locking algorithms in centralized database systems, but few have been developed for distributed ones. Existing results on distributed locking usually ignore the deadlock problem so as to simplify the analysis. In this paper, a new performance model for static locking in distributed database systems is developed.A queuing model is used to approximate static locking in distributed database systems without deadlocks. Then a random graph model is proposed to find the deadlock probability of each transaction. The above two models are integrated, so that given the transaction arrival rate, the response time and the effective throughput can be calculated.

  17. Adaptive function allocation reduces performance costs of static automation

    NASA Technical Reports Server (NTRS)

    Parasuraman, Raja; Mouloua, Mustapha; Molloy, Robert; Hilburn, Brian

    1993-01-01

    Adaptive automation offers the option of flexible function allocation between the pilot and on-board computer systems. One of the important claims for the superiority of adaptive over static automation is that such systems do not suffer from some of the drawbacks associated with conventional function allocation. Several experiments designed to test this claim are reported in this article. The efficacy of adaptive function allocation was examined using a laboratory flight-simulation task involving multiple functions of tracking, fuel-management, and systems monitoring. The results show that monitoring inefficiency represents one of the performance costs of static automation. Adaptive function allocation can reduce the performance cost associated with long-term static automation.

  18. Static load test performance of a telescoping structure for an automatically deployable ROPS.

    PubMed

    Etherton, J R; Cutlip, R G; Harris, J R; Ronaghi, M; Means, K H; Gillispie, A

    2002-02-01

    The automatically deployable ROPS was developed as part of an innovative project to provide passive protection against overturn fatality to operators of new tractors used in both low-clearance and unrestricted-clearance tasks. The primary objective of this phase of the research was to build a telescoping structure that would prove that a ROPS can be built that will (1) reliably deploy on signal, (2) rise in a sufficiently short amount of time, (3) firmly latch in its deployed position, and (4) satisfy SAE J2194 testing requirements. The two-post structure had previously been found to meet deployment time criteria, and design analyses indicated that neither the slip-fit joint nor the latch pins would fail at test loading. Four directions of static loading were applied to the structure to satisfy SAE requirements. For the series of static loading tests, the raised structure was found to maintain a protective clearance zone after all loads were applied. The structure is overly stiff and should be redesigned to increase its ability to absorb ground-impact energy. Results of dynamic tests and field upset tests are reported in companion articles. The next phase of development is to optimize the structure so that it will plastically deform and absorb energy that would otherwise be transferred to the tractor chassis. PMID:12002371

  19. J-Hook Latching Mechanism

    NASA Technical Reports Server (NTRS)

    Milam, M. Bruce

    1992-01-01

    J-hook latching mechanism which joins modules of equipment together and holds cargoes in vehicles relatively simple, strong, and self-aligning. Objects brought together into coarse alignment, shaft turned, causing upper object, mounting bracket, and fixed nut to travel downward on left-handed thread and traveling nut upward on right-handed thread. This allows J-hook to turn under spring load and reach under receptacle.

  20. Manned maneuvering unit latching mechanism

    NASA Technical Reports Server (NTRS)

    Allton, C. S.

    1980-01-01

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

  1. Self-locking MRF latches and dampers

    NASA Astrophysics Data System (ADS)

    Magnac, G.; Claeyssen, F.; Vial, K.; LeLetty, R.; Sosnicki, O.; Benoit, C.

    2009-02-01

    MRF actuators are new electromechanical components using Magneto Rheological Fluids (MRF). When submitted to a high enough magnetic field, MRF switch from a liquid to a near solid body. New MRF actuators were developed in order to reach three aims: to offer a blocking force without power consumption which can be strongly reduced by applying a current, to provide an electrically-controllable resistive force over a stroke of 30 mm, to perform the control of the force in a very short time, typically in a few milliseconds. Thus, these MRF actuators can be used for two main applications: damper and latch - lock. Experiments on two versions of the actuator (a single piston rod and a feed through output axis) allow getting a blocking force around 100N, which is more than 10 times the actuator weight (its mass is 700gr). The current and electric power required to cancel the blocking force are only 1.6A and 4W. the paper further presents the design and the electromechanical properties of the Self-braking MRF Actuators for dampers & latches and new results on the control of these actuators.

  2. Static Aerodynamic Performance Investigation of a Fluid Shield Nozzle

    NASA Technical Reports Server (NTRS)

    Balan, C.; Askew, J. W.

    2005-01-01

    In pursuit of an acoustically acceptable, high performance exhaust system capable of meeting Federal Aviation Regulation 36 Stage 3 noise goals for the High Speed Civil Transport application, General Electric Aircraft Engines conducted a design study to incorporate a fluid shield into a 36-chute suppressor exhaust-nozzle system. After a full scale preliminary mechanical design of the resulting fluid shield exhaust system, scale model aerodynamic performance tests and acoustic tests were conducted to establish both aerodynamic performance and acoustic characteristics. Data are presented as thrust coefficients, discharge coefficients, chute-base pressure drags, and plug static pressure distributions.

  3. Static performance tests of a flight-type STOVL ejector

    NASA Technical Reports Server (NTRS)

    Barankiewicz, Wendy S.

    1991-01-01

    The design and development of thrust augmenting STOVL ejectors has typically been based on experimental iteration (i.e., trial and error). Static performance tests of a full scale vertical lift ejector were performed at primary flow temperatures up to 1560 R (1100 F). Flow visualization (smoke generators and yarn tufts) were used to view the inlet air flow, especially around the primary nozzle and end plates. Performance calculations are presented for ambient temperatures close to 480 R (20 F) and 535 R (75 F) which simulate seasonal aircraft operating conditions. Resulting thrust augmentation ratios are presented as functions of nozzle pressure ratio and temperature.

  4. Assessing the SEU resistance of CMOS latches using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, M.; Blaes, B.; Nixon, R.

    1990-01-01

    The importance of Cosmic Rays on the performance of integrated circuits (IC's) in a space environment is evident in the upset rate of the Tracking and Data Relay Satellite (TDRS) launched in Apr. 1983. This satellite experiences a single-event-upset (SEU) per day which must be corrected from the ground. Such experience caused a redesign of the Galileo spacecraft with SEU resistant IC's. The solution to the SEU problem continues to be important as the complexity of spacecraft grows, the feature size of IC's decreases, and as space systems are designed with circuits fabricated at non-radiation hardened foundries. This paper describes an approach for verifying the susceptibility of CMOS latches to heavy-ion induced state changes. The approach utilizes alpha particles to induce the upsets in test circuits. These test circuits are standard cells that have offset voltages which sensitize the circuits to upsets. These results are then used to calculate the upsetability at operating voltages. In this study results are presented for the alpha particle upset of a six-transistor static random access memory (SRAM) cell. Then a methodology is described for the analysis of a standard-cell inverter latch.

  5. Quick release latch for reactor scram

    DOEpatents

    Johnson, Melvin L.; Shawver, Bruce M.

    1976-01-01

    A simple, reliable, and fast-acting means for releasing a control element and allowing it to be inserted rapidly into the core region of a nuclear reactor for scram purposes. A latch mechanism grips a coupling head on a nuclear control element to connect the control element to the control drive assembly. The latch mechanism is closed by tensioning a cable or rod with an actuator. The control element is released by de-energizing the actuator, providing fail-safe, rapid release of the control element to effect reactor shutdown. A sensing rod provides indication that the control element is properly positioned in the latch. Two embodiments are illustrated, one involving a collet-type latch mechanism, the other a pliers-type latch mechanism with the actuator located inside the reactor vessel.

  6. Quick release latch for reactor scram

    DOEpatents

    Johnson, M.L.; Shawver, B.M.

    1975-09-16

    A simple, reliable, and fast-acting means for releasing a control element and allowing it to be inserted rapidly into the core region of a nuclear reactor for scram purposes is described. A latch mechanism grips a coupling head on a nuclear control element to connect the control element to the control drive assembly. The latch mechanism is closed by tensioning a cable or rod with an actuator. The control element is released by de-energizing the actuator, providing fail-safe, rapid release of the control element to effect reactor shutdown. A sensing rod provides indication that the control element is properly positioned in the latch. Two embodiments are illustrated, one involving a collet- type latch mechanism, the other a pliers-type latch mechanism with the actuator located inside the reactor vessel. (auth)

  7. Four-Point-Latching Microactuator

    NASA Technical Reports Server (NTRS)

    Toda, Risaku; Yang, Eui-Hyeok

    2008-01-01

    An experimental inchworm-type linear microactuator is depicted. This microactuator is a successor to one described in "MEMS-Based Piezoelectric/Electrostatic Inchworm Actuator" (NPO-30672), NASA Tech Briefs, Vol. 27, No. 6 (June 2003), page 68. Both actuators are based on the principle of using a piezoelectric transducer operated in alternation with electrostatically actuated clutches to cause a slider to move in small increments. However, the design of the present actuator incorporates several improvements over that of the previous one. The most readily apparent improvement is in geometry and, consequently, in fabrication: In the previous actuator, the inchworm motion was perpendicular to the broad faces of a flat silicon wafer on which the actuator was fabricated, and fabrication involved complex processes to form complex three-dimensional shapes in and on the wafer. In the present actuator, the inchworm motion is parallel to the broad faces of a wafer on which it is fabricated. The components needed to produce the in-plane motion are nearly planar in character and, consequently, easier to fabricate. Other advantages of the present design are described, including that the previous actuator contained two clutches (denoted 'holders' in the cited prior article), the present actuator contains four clutches. The operational sequence of the previous two-clutch actuator is similar. However, the two-clutch configuration is susceptible to tilt of the slider and a consequent large increase in drag. Hence, the primary operational advantages of the present four-point-latching design over the prior two-point-latching design are less drag and greater control robustness arising from greater stability of the orientation of the slider.

  8. Development of a high force thermal latch

    NASA Astrophysics Data System (ADS)

    Nygren, William D.

    1995-05-01

    This paper describes the preliminary development of a high force thermal latch (HFTL). The HFTL has one moving part which is restrained in the latched position by a low melting temperature or fusible metal alloy. When heated the fusible alloy flows to a receiving chamber and in so doing at first releases the tension load in the latch bolt and later releases the bolt itself. The HFTL can be used in place of pyrotechnically activated spacecraft release devices in those instances where the elimination of both pyrotechnic shock-loading and rapid strain-energy release take precedence over the near instantaneous release offered by ordnance initiated devices.

  9. Development of a high force thermal latch

    NASA Technical Reports Server (NTRS)

    Nygren, William D.

    1995-01-01

    This paper describes the preliminary development of a high force thermal latch (HFTL). The HFTL has one moving part which is restrained in the latched position by a low melting temperature or fusible metal alloy. When heated the fusible alloy flows to a receiving chamber and in so doing at first releases the tension load in the latch bolt and later releases the bolt itself. The HFTL can be used in place of pyrotechnically activated spacecraft release devices in those instances where the elimination of both pyrotechnic shock-loading and rapid strain-energy release take precedence over the near instantaneous release offered by ordnance initiated devices.

  10. Fertilization test performance using Arbacia punctulata maintained in static culture

    SciTech Connect

    Serbst, J.R.; Wright, L.; Sheehan, C.V.; Fitzpatrick, K.

    1995-12-31

    The sea urchin fertilization test using the Atlantic urchin, Arbacia punctulata, is widely utilized in evaluating toxicity of receiving waters and effluents as part of the NPDES program. While this species is easily maintained in uncontaminated, flow-through seawater systems, laboratories without access to flowing seawater either obtain new urchins for each test or maintain populations in static cultures. This study was conducted to assess test success and reproducibility of fertilization tests conducted using urchins maintained in separate-sex, static, temperature-controlled aquaria containing filtered natural seawater. Test performance was evaluated by periodically conducting the standard sea urchin fertilization test (EPA 600/4-87-028) using a common reference toxicant, sodium dodecyl sulfate (SDS) Thirteen tests were conducted between September 1993 and May 1994 using one population of urchins, and five tests were conducted between June and December 1994 with a second population of urchins. Test success was 100% (control fertilization > 50%) with a control fertilization mean of 96.4% (S.D. = 3.3). There were no differences between mean EC{sub 50} values calculated for each set of tests (p < 0.05). The running mean value for toxicity was 7.1 mg/L (S.D. = 1.26) for 18 tests, with a CV of 17.7%, comparing favorably with values generated using urchins maintained in flowing seawater. The running mean value for toxicity in these tests was 2.4 mg/L (S.D. = 0.9) for 18 tests conducted between November 1987 and July 1989 (ASTM STP 1124). Data from all urchin tests were used to construct a control chart defining normal ranges for SDS toxicity. This study demonstrated that fertile, adult sea urchins can produce consistent toxicity responses with low variability while being maintained in static, temperature regulated culture facilities.

  11. Predicting performance in competitive apnoea diving. Part I: static apnoea.

    PubMed

    Schagatay, Erika

    2009-06-01

    Ever since the first deep diving competitions were organized, there has been debate about when the ultimate limits of human apnoeic performance will be reached, and which factors will determine these limits. Divers have thus far surpassed all former predictions by physiologists in depth and time. The common factor for all competitive apnoea disciplines is apnoeic duration, which can be prolonged by any means that increase total gas storage or tolerance to asphyxia, or reduce metabolic rate. These main factors can be broken down further into several physiological or psychophysiological factors, which are identified in this review. Like in other sports, the main aim in competitive apnoea is to extend human performance beyond the known limits. While a beginner may extend apnoeic duration by getting closer to his or her personal limit, the elite diver can only extend the duration further by pushing the individual physiological limit further by training. In order to achieve this, it is essential to identify the performance predicting factors of apnoea sports and which factors can be affected by training, work that has only just begun. This is the first of two papers reviewing the main factors predicting performance in competitive apnoea diving, which focuses on static apnoea, while the following paper will review dynamic distance and depth disciplines. Great improvements have been made in all diving disciplines in recent years and the 10-minute barrier in resting 'static apnoea' has been broached. Despite this, current training methods and the strategies employed suggest that duration can be prolonged still further, and divers themselves suggest the ultimate limit will be 15 minutes, which appears physiologically possible, for example, with further development of techniques to reduce metabolic rate. PMID:22753202

  12. Dual-action expanded-latch mechanism

    NASA Technical Reports Server (NTRS)

    Spencer, R. A.; Tewell, J. R.; Tobey, W. H.

    1978-01-01

    Single drive actuator operates novel mechanism that expands, attaches to object, and withdraws to latch object firmly to another part. Packaging is extremely simple and compact, and eliminates need for machined parts or close tolerances.

  13. Interpersonal synergies: static prehension tasks performed by two actors.

    PubMed

    Solnik, Stanislaw; Reschechtko, Sasha; Wu, Yen-Hsun; Zatsiorsky, Vladimir M; Latash, Mark L

    2016-08-01

    We investigated multidigit synergies stabilizing components of the resultant force vector during joint performance of a static prehension task by two persons as compared to similar tasks performed by a single person using both hands. Subjects transferred the instrumented handle from the right hand to the left hand (one-person condition) or passed that handle to another person (two-person condition) while keeping the handle's position and orientation stationary. Only three digits were involved per hand, the thumb, the index finger, and the middle finger; the forces and moments produced by the digits were measured by six-component sensors. We estimated the performance-stabilizing synergies within the uncontrolled manifold framework by quantifying the intertrial variance structure of digit forces and moments. The analysis was performed at three levels: between hands, between virtual finger and virtual thumb (imagined digits producing the same mechanical variables as the corresponding actual digits combined) produced by the two hands (in both interpersonal and intrapersonal conditions), and between the thumb and virtual finger for one hand only. Additionally, we performed correlation and phase synchronization analyses of resultant tangential forces and internal normal forces. Overall, the one-person conditions were characterized by higher amount of intertrial variance that did not affect resultant normal force components, higher internal components of normal forces, and stronger synchronization of the normal forces generated by the hands. Our observations suggest that in two-person tasks, when participants try to achieve a common mechanical outcome, the performance-stabilizing synergies depend on non-visual information exchange, possibly via the haptic and proprioceptive systems. Therefore, synergies quantified in tasks using visual feedback only may not be generalizable to more natural tasks. PMID:27021074

  14. STATIC STRETCHING DOES NOT REDUCE VARIABILITY, JUMP AND SPEED PERFORMANCE

    PubMed Central

    Rama, Luís Manuel Pinto Lopes

    2016-01-01

    Background Stretching is often part of the warm-up routine prior to athletic participation; however, controversial evidence exists on the effects of stretching on countermovement jump (CMJ) and sprint performance. Additionally, analysis of variability between repeated tasks is useful for monitoring players, to analyze factors that could affect the performance, and to guide clinical decisions for training strategies. Purpose The purpose of this study was to examine whether static stretching (SS) prior to CMJ and 20-meter (20-m) sprint would affect performance, and to investigate whether SS affects an athlete's ability to perform these tasks consistently. Methods Twenty-two trained healthy athletes (23.2 ± 5.0 years) attended, randomly, two testing sessions, separated by 48 hours. At session one, all participants underwent 10 minutes of dynamic running warm-up followed by the experimental tasks (three CMJ and three 20-m sprint), whereas five minutes of stretching was added after the warm-up routine at session two. All participants performed the same experimental tasks in both sessions. The stretching protocol consisted of five stretching exercises for each lower limb. Results The paired-samples t-test revealed no significant differences between the stretching protocol condition and no stretching condition for the 20-m sprint (t(21)=.920; p=.368) and CMJ (t(21)=.709; p=.486). There were no significant differences in trial-by-trial variability on 20-m sprint (t(21)=1.934; p=.067) and CMJ scores (t(21)=.793; p=.437) as result of SS. Conclusion The SS protocol did not modify jumping and running ability in trained healthy athletes. The SS prior to training or competition may not cause detrimental effects to athletic performance. Level of evidence Level III, Nonrandomized controlled trial. PMID:27104057

  15. A high-speed and low-offset dynamic latch comparator.

    PubMed

    Rahman, Labonnah Farzana; Bin Ibne Reaz, Mamun; Yin, Chia Chieu; Marufuzzaman, Mohammad; Rahman, Mohammad Anisur

    2014-01-01

    Circuit intricacy, speed, low-offset voltage, and resolution are essential factors for high-speed applications like analog-to-digital converters (ADCs). The comparator circuit with preamplifier increases the power dissipation, as it requires higher amount of currents than the latch circuitry. In this research, a novel topology of dynamic latch comparator is illustrated, which is able to provide high speed, low offset, and high resolution. Moreover, the circuit is able to reduce the power dissipation as the topology is based on latch circuitry. The cross-coupled circuit mechanism with the regenerative latch is employed for enhancing the dynamic latch comparator performance. In addition, input-tracking phase is used to reduce the offset voltage. The Monte-Carlo simulation results for the designed comparator in 0.18 μm CMOS process show that the equivalent input-referred offset voltage is 720 μV with 3.44 mV standard deviation. The simulated result shows that the designed comparator has 8-bit resolution and dissipates 158.5 μW of power under 1.8 V supply while operating with a clock frequency of 50 MHz. In addition, the proposed dynamic latch comparator has a layout size of 148.80 μm × 59.70 μm. PMID:25114959

  16. A High-Speed and Low-Offset Dynamic Latch Comparator

    PubMed Central

    Rahman, Labonnah Farzana; Reaz, Mamun Bin Ibne; Yin, Chia Chieu; Rahman, Mohammad Anisur

    2014-01-01

    Circuit intricacy, speed, low-offset voltage, and resolution are essential factors for high-speed applications like analog-to-digital converters (ADCs). The comparator circuit with preamplifier increases the power dissipation, as it requires higher amount of currents than the latch circuitry. In this research, a novel topology of dynamic latch comparator is illustrated, which is able to provide high speed, low offset, and high resolution. Moreover, the circuit is able to reduce the power dissipation as the topology is based on latch circuitry. The cross-coupled circuit mechanism with the regenerative latch is employed for enhancing the dynamic latch comparator performance. In addition, input-tracking phase is used to reduce the offset voltage. The Monte-Carlo simulation results for the designed comparator in 0.18 μm CMOS process show that the equivalent input-referred offset voltage is 720 μV with 3.44 mV standard deviation. The simulated result shows that the designed comparator has 8-bit resolution and dissipates 158.5 μW of power under 1.8 V supply while operating with a clock frequency of 50 MHz. In addition, the proposed dynamic latch comparator has a layout size of 148.80 μm × 59.70 μm. PMID:25114959

  17. Minimal Power Latch for Single-Slope ADCs

    NASA Technical Reports Server (NTRS)

    Hancock, Bruce R. (Inventor)

    2015-01-01

    A latch circuit that uses two interoperating latches. The latch circuit has the beneficial feature that it switches only a single time during a measurement that uses a stair step or ramp function as an input signal in an analog to digital converter. This feature minimizes the amount of power that is consumed in the latch and also minimizes the amount of high frequency noise that is generated by the latch. An application using a plurality of such latch circuits in a parallel decoding ADC for use in an image sensor is given as an example.

  18. Tailless aircraft performance improvements with relaxed static stability

    NASA Technical Reports Server (NTRS)

    Ashkenas, Irving L.; Klyde, David H.

    1989-01-01

    The purpose is to determine the tailless aircraft performance improvements gained from relaxed static stability, to quantify this potential in terms of range-payload improvements, and to identify other possible operational and handling benefits or problems. Two configurations were chosen for the study: a modern high aspect ratio, short-chord wing proposed as a high-altitude long endurance (HALE) remotely piloted vehicle; a wider, lower aspect ratio, high volume wing suitable for internal stowage of all fuel and payload required for a manned long-range reconnaissance mission. Flying at best cruise altitude, both unstable configurations were found to have a 14 percent improvement in range and a 7 to 9 percent improvement in maximum endurance compared to the stable configurations. The unstable manned configuration also shows a 15 percent improvement in the 50 ft takeoff obstacle distance and an improved height response to elevator control. However, it is generally more deficient in control power due to its larger adverse aileron yaw and its higher takeoff and landing lift coefficient C(sub L), both due to the downward trimmed (vs. upward trimmed for stable configurations) trailing edge surfaces.

  19. Static Performance of a Wing-Mounted Thrust Reverser Concept

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    1998-01-01

    An experimental investigation was conducted in the Jet-Exit Test Facility at NASA Langley Research Center to study the static aerodynamic performance of a wing-mounted thrust reverser concept applicable to subsonic transport aircraft. This innovative engine powered thrust reverser system is designed to utilize wing-mounted flow deflectors to produce aircraft deceleration forces. Testing was conducted using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0, a supercritical left-hand wing section attached via a pylon, and wing-mounted flow deflectors attached to the wing section. Geometric variations of key design parameters investigated for the wing-mounted thrust reverser concept included flow deflector angle and chord length, deflector edge fences, and the yaw mount angle of the deflector system (normal to the engine centerline or parallel to the wing trailing edge). All tests were conducted with no external flow and high pressure air was used to simulate core and fan engine exhaust flows. Test results indicate that the wing-mounted thrust reverser concept can achieve overall thrust reverser effectiveness levels competitive with (parallel mount), or better than (normal mount) a conventional cascade thrust reverser system. By removing the thrust reverser system from the nacelle, the wing-mounted concept offers the nacelle designer more options for improving nacelle aero dynamics and propulsion-airframe integration, simplifying nacelle structural designs, reducing nacelle weight, and improving engine maintenance access.

  20. Wind powered generator with cyclic airfoil latching

    SciTech Connect

    Bair, P.

    1981-12-01

    A wind powered generator rotatable about a vertical axis is described. A plurality of vertically disposed airfoils are provided, the airfoils being rotatable about a vertical axis parallel to the axis of the generator. The airfoils are selectively latched to be disposed perpendicularly of the wind direction during one phase of their revolution about the generator axis and are selectively unlatched to be permitted to rotate into a position generally parallel to the wind direction during other phases of their revolution. The latching and unlatching of the airfoils is determined by the wind direction and is effected by electronic means which determine the point of latching and unlatching as a function of the wind direction measured by a wind vane. The airfoils may comprise sails composed of a flexible material stretched into a predetermined shape on a frame.

  1. Quasi-static rotor morphing concepts for rotorcraft performance improvements

    NASA Astrophysics Data System (ADS)

    Mistry, Mihir

    The current research is focused on two separate quasi-static rotor morphing concepts: Variable span and variable camber. Both concepts were analyzed from the perspective of the performance improvements they allow for, as well as their design requirements. The goal of this body of work is to develop a comprehensive understanding of the benefits and implementation challenges of both systems. For the case of the variable span rotor concept, the effects on aircraft performance were evaluated for a UH-60A type aircraft. The parametric analysis included the performance effects of the rotor span and rotor speed variation, both individually as well as in combination. The design space considered the effect of three different gross weights (16000 lbs, 18300 lbs and 24000 lbs), for a window of +/-11% variation of the rotor speed and a range between +17% to --16% of radius variation (about the baseline) for a range of altitudes. The results of the analysis showed that variable span rotors by themselves are capable of reducing the power requirement of the helicopter by up to 20% for high altitude and gross weight conditions. However, when combined with rotor speed variation, it was possible to reduce the overall power required by the aircraft by up to 30%. Complimentary to the performance analysis, an analytical study of actuation concepts for a variable span rotor was also conducted. This study considered the design of two active actuation systems: Hydraulic pistons and threaded rods (jackscrews), and two passive systems which employed the use of an internal spring type restraining device. For all the configurations considered, it was determined that the design requirements could not be satisfied when considering the constraints defined. The performance improvements due to a variable camber system were evaluated for a BO-105 type rotor in hover. The design space considered included three different thrust levels (4800 lbs, 5500 lbs and 6400 lbs) for a range of altitudes and

  2. Computer programs for estimation of STOL takeoff, landing, and static performance

    NASA Technical Reports Server (NTRS)

    Post, S. E.

    1972-01-01

    A set of computer programs has been developed for evaluating the performance of powered-lift STOL aircraft. Included are a static performance summary and dynamic calculations of takeoff and landing performance. The input, output, options, and calculations for each program are described. The programs are written in FORTRAN IV and are currently available on TSS 360. Three independent sections are presented corresponding to the three programs: (1) static performance, (2) takeoff performance, and (3) landing performance.

  3. Misuse Study of Latch Attachment: A Series of Frontal Sled Tests

    PubMed Central

    Menon, Rajiv; Ghati, Yoganand

    2007-01-01

    This study was initiated to quantify the effects of the misuse in LATCH lower webbing. In the short period since the implementation of the LATCH system several cases of potential misuses have been reported. A series of sled tests in frontal impact mode were conducted with various misuse conditions (loose attachment of LATCH lower webbing, misrouting of LATCH lower webbing and child seat back inclination) for both forward and rearward facing child safety seats (FFCSS and RFCSS). Results from these tests are compared and discussed with that of the standard test with no misuse and showed that as the slack in the lower LATCH webbing increased, ATD injury measures exceeded the limits. The FFCSS tests in the reclined condition yielded lower injury values for all except the chest G’s when compared to the standard upright test. In the misrouting tests the ATD kinematics depended on the routing pivot point, the lower the pivot point the better the ATD kinematics. Similar findings were also observed in the RFCSS tests. The use of top tether with the FFCSS substantially improved the performance of the Hybrid III 3 year old ATD in spite of misuse conditions and the injury values were lower than the corresponding tests with no top tether. The effective reduction was 37% in the HIC values, 6% in the chest G’s, 30% in the head excursion, 22 % in the knee excursion and finally 37 % reduction in the Nij values. PMID:18184489

  4. Misuse study of latch attachment: a series of frontal sled tests.

    PubMed

    Menon, Rajiv; Ghati, Yoganand

    2007-01-01

    This study was initiated to quantify the effects of the misuse in LATCH lower webbing. In the short period since the implementation of the LATCH system several cases of potential misuses have been reported. A series of sled tests in frontal impact mode were conducted with various misuse conditions (loose attachment of LATCH lower webbing, misrouting of LATCH lower webbing and child seat back inclination) for both forward and rearward facing child safety seats (FFCSS and RFCSS). Results from these tests are compared and discussed with that of the standard test with no misuse and showed that as the slack in the lower LATCH webbing increased, ATD injury measures exceeded the limits. The FFCSS tests in the reclined condition yielded lower injury values for all except the chest G's when compared to the standard upright test. In the misrouting tests the ATD kinematics depended on the routing pivot point, the lower the pivot point the better the ATD kinematics. Similar findings were also observed in the RFCSS tests. The use of top tether with the FFCSS substantially improved the performance of the Hybrid III 3 year old ATD in spite of misuse conditions and the injury values were lower than the corresponding tests with no top tether. The effective reduction was 37% in the HIC values, 6% in the chest G's, 30% in the head excursion, 22 % in the knee excursion and finally 37 % reduction in the Nij values. PMID:18184489

  5. Magnetic latch trigger for inherent shutdown assembly

    DOEpatents

    Sowa, Edmund S.

    1976-01-01

    An inherent shutdown assembly for a nuclear reactor is provided. A neutron absorber is held ready to be inserted into the reactor core by a magnetic latch. The latch includes a magnet whose lines of force are linked by a yoke of material whose Curie point is at the critical temperature of the reactor at which the neutron absorber is to be inserted into the reactor core. The yoke is in contact with the core coolant or fissionable material so that when the coolant or the fissionable material increase in temperature above the Curie point the yoke loses its magnetic susceptibility and the magnetic link is broken, thereby causing the absorber to be released into the reactor core.

  6. Releasable latch for downhole well tools

    SciTech Connect

    Setterberg, J.R. Jr.

    1986-02-18

    This patent describes a latch for releasably anchoring well tools at a preselected downhole location defined in part by an annular recess. The latch consists of: a. a mandrel; b. a device for locking the mandrel with the recess; c. the locking means slidably mounted on the mandrel; d. a backup device having a first position which allows disengagement of the locking device from the recess and a second position which holds the locking device against disengagement from the recess; e. a first frangible device holding the backup device in its first position and releasing the backup device in response to application of a predetermined force tending to move the backup device to its second position; and f. a second frangible device for holding the backup device in its second position.

  7. The actuated latch pin and its development

    NASA Technical Reports Server (NTRS)

    Lawlor, P. J.

    1980-01-01

    An actuated latch pin developed to meet the need for a reusable locking device is described. The unit can function as a pin puller or as a pin pusher latch. Initial prototype testing demonstrated the feasibility of the device with the unit being driven from a 28 V dc supply and using 15 W to drive a 12 mm diameter pin through a stroke of 10 mm with a side load of 100 N in 120 ms. High wear rates with a MOS2 lubrication on the ballscrew and angular contact bearings have necessitated the reduction in the duty cycle from 1000 cycles in air and vacuum to 100 in air and 1000 in vacuum.

  8. Non-latching relay switch assembly

    DOEpatents

    Duimstra, Frederick A.

    1991-01-01

    A non-latching relay switch assembly which includes a coil section and a switch or contact section. The coil section includes a permanent magnet and an electromagnet. The respective sections are arranged in separate locations or cavities in the assembly. The switch has a "normal" position and is selectively switched by an overriding electromagnetic assembly. The switch returns to the "normal" position when the overriding electromagnetic assembly is inactive.

  9. Door latching recognition apparatus and process

    DOEpatents

    Eakle, Jr., Robert F.

    2012-05-15

    An acoustic door latch detector is provided in which a sound recognition sensor is integrated into a door or door lock mechanism. The programmable sound recognition sensor can be trained to recognize the acoustic signature of the door and door lock mechanism being properly engaged and secured. The acoustic sensor will signal a first indicator indicating that proper closure was detected or sound an alarm condition if the proper acoustic signature is not detected within a predetermined time interval.

  10. Bistable (latching) solenoid actuated propellant isolation valve

    NASA Technical Reports Server (NTRS)

    Wichmann, H.; Deboi, H. H.

    1979-01-01

    The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve features a balanced poppet, utilizing metal bellows, a hard poppet/seat interface and a flexure support system for the internal moving components. This support system eliminates sliding surfaces, thereby rendering the valve free of self generated particles.

  11. Iterative solution of large, sparse linear systems on a static data flow architecture - Performance studies

    NASA Technical Reports Server (NTRS)

    Reed, D. A.; Patrick, M. L.

    1985-01-01

    The applicability of static data flow architectures to the iterative solution of sparse linear systems of equations is investigated. An analytic performance model of a static data flow computation is developed. This model includes both spatial parallelism, concurrent execution in multiple PE's, and pipelining, the streaming of data from array memories through the PE's. The performance model is used to analyze a row partitioned iterative algorithm for solving sparse linear systems of algebraic equations. Based on this analysis, design parameters for the static data flow architecture as a function of matrix sparsity and dimension are proposed.

  12. Performance of D-bolts Under Static Loading

    NASA Astrophysics Data System (ADS)

    Li, Charlie C.

    2012-03-01

    D-bolt is a type of energy-absorbing rock bolt. It is made of a smooth steel bar with anchors spaced along the bolt length. A typical section between adjacent anchors is approximately 1-m long, but it can be adjusted to adapt to the rock conditions. The bolt is fully encapsulated with either cement or resin grout in a borehole. The anchors are firmly fixed into the grout, while the smooth bolt sections can freely deform to absorb deformation energy. Full-scale static pull tests were carried out at different testing facilities in two laboratories. The tests show that a smooth bolt section between anchors may elongate by 110-167 mm depending on the section length. Field trials of the D-bolt were conducted in deep metal mines. The measurements showed that the D-bolts were equally loaded within every anchor-between section, avoiding load peaks and premature bolt failure due to stress concentrations caused by fracture/joint opening. The field trials of rebar and D-bolts in a largely deformed mine tunnel showed that the D-bolts behaved satisfactorily, with only a few failed bolts, while a number of the rebar bolts failed at the thread.

  13. Three-dimensional simulation of rotary latch assembly in seismic response and interactions

    SciTech Connect

    Leung, K.K.

    1998-03-02

    The finite element method has been used to investigate the stress field in mechanical suspension systems. The critical seismic loads are depended on three-dimensional dynamic response of vacuum vessels and interactions of the equipment supporting structures to the vacuum vessels and supporting system. In this study of the optics assembly equipment (15 to 27 Hz), it was shown that the pressure vessel systems which supports the optics assembly systems (6.5 to 13 Hz) have significant influence in the seismic response of the rotary latch assembly. A potentially critical failure location is identified. An axisymmetrical elastic analysis predicts stress at the inner radius of the lower housing can be reduced by 60% with simple design modification. Use of three-dimensional dynamic model and static model to evaluate the combined complex stress permits prediction of the rotary latch assembly operating life and seismic safety.

  14. A Modular, Reusable Latch and Decking System for Securing Payloads During Launch and Planetary Surface Transport

    NASA Technical Reports Server (NTRS)

    Doggett, William R.; Dorsey, John T.; Jones, Thomas C.; King, Bruce D.; Mikulas, Martin M.

    2011-01-01

    Efficient handling of payloads destined for a planetary surface, such as the moon or mars, requires robust systems to secure the payloads during transport on the ground, in space and on the planetary surface. In addition, mechanisms to release the payloads need to be reliable to ensure successful transfer from one vehicle to another. An efficient payload handling strategy must also consider the devices available to support payload handling. Cranes used for overhead lifting are common to all phases of payload handling on Earth. Similarly, both recent and past studies have demonstrated that devices with comparable functionality will be needed to support lunar outpost operations. A first generation test-bed of a new high performance device that provides the capabilities of both a crane and a robotic manipulator, the Lunar Surface Manipulation System (LSMS), has been designed, built and field tested and is available for use in evaluating a system to secure payloads to transportation vehicles. A payload handling approach must address all phases of payload management including: ground transportation, launch, planetary transfer and installation in the final system. In addition, storage may be required during any phase of operations. Each of these phases requires the payload to be lifted and secured to a vehicle, transported, released and lifted in preparation for the next transportation or storage phase. A critical component of a successful payload handling approach is a latch and associated carrier system. The latch and carrier system should minimize requirements on the: payload, carrier support structure and payload handling devices as well as be able to accommodate a wide range of payload sizes. In addition, the latch should; be small and lightweight, support a method to apply preload, be reusable, integrate into a minimal set of hard-points and have manual interfaces to actuate the latch should a problem occur. A latching system which meets these requirements has been

  15. A Modular, Reusable Latch and Decking System for Securing Payloads During Launch and Planetary Surface Transport

    NASA Technical Reports Server (NTRS)

    Doggett, William R.; Dorsey, John T.; Jones, Thomas C.; King, Bruce D.; Mikulas, Martin M.

    2010-01-01

    Efficient handling of payloads destined for a planetary surface, such as the moon or Mars, requires robust systems to secure the payloads during transport on the ground, in-space and on the planetary surface. In addition, mechanisms to release the payloads need to be reliable to ensure successful transfer from one vehicle to another. An efficient payload handling strategy must also consider the devices available to support payload handling. Cranes used for overhead lifting are common to all phases of payload handling on Earth. Similarly, both recent and past studies have demonstrated that devices with comparable functionality will be needed to support lunar outpost operations. A first generation test-bed of a new high performance device that provides the capabilities of both a crane and a robotic manipulator, the Lunar Surface Manipulation System (LSMS), has been designed, built and field tested and is available for use in evaluating a system to secure payloads to transportation vehicles. National Institute of Aerospace, Hampton Va 23662 A payload handling approach must address all phases of payload management including: ground transportation, launch, planetary transfer and installation in the final system. In addition, storage may be required during any phase of operations. Each of these phases requires the payload to be lifted and secured to a vehicle, transported, released and lifted in preparation for the next transportation or storage phase. A critical component of a successful payload handling approach is a latch and associated carrier system. The latch and carrier system should minimize requirements on the: payload, carrier support structure and payload handling devices as well as be able to accommodate a wide range of payload sizes. In addition, the latch should; be small and lightweight, support a method to apply preload, be reusable, integrate into a minimal set of hard-points and have manual interfaces to actuate the latch should a problem occur. A

  16. A novel tape spring hinge mechanism for quasi-static deployment of a satellite deployable using shape memory alloy

    NASA Astrophysics Data System (ADS)

    Jeong, Ju Won; Yoo, Young Ik; Shin, Dong Kil; Lim, Jae Hyuk; Kim, Kyung Won; Lee, Jung Ju

    2014-02-01

    A tape spring hinge (TSH) is a typical flexible deployment device for a satellite and becomes frequently used due to its simplicity, lightweight, low cost, and high deployment reliability. However, the performance of a TSH is quite limited due to trade-offs among deployed stiffness, deployment torque, and latch-up shock despite its many advantages. In this study, a novel conceptual design that circumvents the trade-offs among functional requirements (FRs) is proposed. The trade-offs are obviated by a newly proposed shape memory alloy damper that converts the deployment behavior of a conventional TSH from unstable dynamic to stable quasi-static. This makes it possible to maximize the deployment stiffness and deployment torque of a conventional TSH, which are larger-the-better FR, without any increase in the latch-up shock. Therefore, in view of conceptual design, it is possible to design a highly improved TSH that has much higher deployed stiffness and deployment torque compared to a conventional TSH while minimizing latch-up shock and deployment unstableness. Detailed design was performed through response surface method and finite element analysis. Finally, a prototype was manufactured and tested in order to verify its performance (four point, deployment torque, and latch-up shock tests). The test results confirm the feasibility of the proposed TSH mechanism.

  17. Acute dietary nitrate supplementation improves dry static apnea performance.

    PubMed

    Engan, Harald K; Jones, Andrew M; Ehrenberg, Fanny; Schagatay, Erika

    2012-07-01

    Acute dietary nitrate (NO₃⁻) supplementation has been reported to lower resting blood pressure, reduce the oxygen (O₂) cost of sub-maximal exercise, and improve exercise tolerance. Given the proposed effects of NO₃⁻ on tissue oxygenation and metabolic rate, it is possible that NO₃⁻ supplementation might enhance the duration of resting apnea. If so, this might have important applications both in medicine and sport. We investigated the effects of acute NO₃⁻ supplementation on pre-apnea blood pressure, apneic duration, and the heart rate (HR) and arterial O₂ saturation (SaO₂) responses to sub-maximal and maximal apneas in twelve well-trained apnea divers. Subjects were assigned in a randomized, double blind, crossover design to receive 70 ml of beetroot juice (BR; containing ∼5.0 mmol of nitrate) and placebo juice (PL; ∼0.003 mmol of nitrate) treatments. At 2.5 h post-ingestion, the subjects completed a series of two 2-min (sub-maximal) static apneas separated by 3 min of rest, followed by a maximal effort apnea. Relative to PL, BR reduced resting mean arterial pressure by 2% (PL: 86±7 vs. BR: 84 ± 6 mmHg; P=0.04). The mean nadir for SaO₂ after the two sub-maximal apneas was 97.2±1.6% in PL and 98.5±0.9% in BR (P=0.03) while the reduction in HR from baseline was not significantly different between PL and BR. Importantly, BR increased maximal apneic duration by 11% (PL: 250 ± 58 vs. BR: 278±64s; P=0.04). In the longer maximal apneas in BR, the magnitude of the reductions in HR and SaO₂ were greater than in PL (P ≤ 0.05). The results suggest that acute dietary NO₃⁻ supplementation may increase apneic duration by reducing metabolic costs. PMID:22588047

  18. Evaluation of Pseudo-Static Coefficients According to Performance-Based Criteria

    SciTech Connect

    Biondi, Giovanni; Maugeri, Michele; Cascone, Ernesto

    2008-07-08

    A rational procedure is presented for the selection of the equivalent seismic coefficient to be introduced in the pseudo-static analysis of geotechnical systems which, at failure, behave as a 1-degree of freedom system. It is shown that although pseudo-static and displacement analyses may be regarded as alternative methods of analysis, the seismic coefficient may be related to earthquake-induced permanent displacements and, then, to the expected level of damage. Following the proposed procedure a pseudo-static analysis in accordance with performance based design can be carried out.

  19. Performance analysis of static locking in replicated distributed database systems

    NASA Technical Reports Server (NTRS)

    Kuang, Yinghong; Mukkamala, Ravi

    1991-01-01

    Data replications and transaction deadlocks can severely affect the performance of distributed database systems. Many current evaluation techniques ignore these aspects, because it is difficult to evaluate through analysis and time consuming to evaluate through simulation. Here, a technique is discussed that combines simulation and analysis to closely illustrate the impact of deadlock and evaluate performance of replicated distributed databases with both shared and exclusive locks.

  20. Performance analysis of static locking in replicated distributed database systems

    NASA Technical Reports Server (NTRS)

    Kuang, Yinghong; Mukkamala, Ravi

    1991-01-01

    Data replication and transaction deadlocks can severely affect the performance of distributed database systems. Many current evaluation techniques ignore these aspects, because it is difficult to evaluate through analysis and time consuming to evaluate through simulation. A technique is used that combines simulation and analysis to closely illustrate the impact of deadlock and evaluate performance of replicated distributed database with both shared and exclusive locks.

  1. Engineering Evaluation of International Low Impact Docking System Latch Hooks

    NASA Technical Reports Server (NTRS)

    Martinez, J.; Patin, R.; Figert, J.

    2013-01-01

    The international Low Impact Docking System (iLIDS) provides a structural arrangement that allows for visiting vehicles to dock with the International Space Station (ISS) (Fig 1). The iLIDS docking units are mechanically joined together by a series of active and passive latch hooks. In order to preserve docking capability at the existing Russian docking interfaces, the iLIDS latch hooks are required to conform to the existing Russian design. The latch hooks are classified as being fail-safe. Since the latch hooks are fail-safe, the hooks are not fracture critical and a fatigue based service life assessment will satisfy the structural integrity requirements. Constant amplitude fatigue testing to failure on four sets of active/passive iLIDS latch hooks was performed at load magnitudes of 10, 11, and 12 kips. Failure analysis of the hook fatigue failures identified multi-site fatigue initiation that was effectively centered about the hook mid-plane (consistent with the 3D model results). The fatigue crack initiation distribution implies that the fatigue damage accumulation effectively results in a very low aspect ratio surface crack (which can be simulated as thru-thickness crack). Fatigue damage progression resulted in numerous close proximity fatigue crack initiation sites. It was not possible to determine if fatigue crack coalescence occurs during cyclic loading or as result of the fast fracture response. The presence of multiple fatigue crack initiation sites on different planes will result in the formation of ratchet marks as the cracks coalesce. Once the stable fatigue crack becomes unstable and the fast fracture advances across the remaining ligament and the plane stress condition at a free-surface will result in failure along a 45 deg. shear plane (slant fracture) and the resulting inclined edge is called a shear lip. The hook thickness on the plane of fatigue crack initiation is 0.787". The distance between the shear lips on this plane was on the order of 0

  2. Static performance of five twin-engine nonaxisymmetric nozzles with vectoring and reversing capability

    NASA Technical Reports Server (NTRS)

    Capone, F. J.

    1978-01-01

    Transonic tunnel test was performed to determine the static performance of five twin-engine nonaxisymmetric nozzles and a base-line axisymmetric nozzle at three nozzle power settings. Static thrust-vectoring and thrust-reversing performance were also determined. Nonaxisymmetric-nozzle concepts included two-dimensional convergent-divergent nozzles, wedge nozzles, and a nozzle with a single external-expansion ramp. All nonaxisymmetric nozzles had essentially the same statis performance as the axisymmetric nozzle. Effective thrust vectoring and reversing was also achieved.

  3. Gate drive latching circuit for an auxiliary resonant commutation circuit

    NASA Technical Reports Server (NTRS)

    Delgado, Eladio Clemente (Inventor); Kheraluwala, Mustansir Hussainy (Inventor)

    1999-01-01

    A gate drive latching circuit for an auxiliary resonant commutation circuit for a power switching inverter includes a current monitor circuit providing a current signal to a pair of analog comparators to implement latching of one of a pair of auxiliary switching devices which are used to provide commutation current for commutating switching inverters in the circuit. Each of the pair of comparators feeds a latching circuit which responds to an active one of the comparators for latching the associated gate drive circuit for one of the pair of auxiliary commutating switches. An initial firing signal is applied to each of the commutating switches to gate each into conduction and the resulting current is monitored to determine current direction and therefore the one of the switches which is carrying current. The comparator provides a latching signal to the one of the auxiliary power switches which is actually conducting current and latches that particular power switch into an on state for the duration of current through the device. The latching circuit is so designed that the only time one of the auxiliary switching devices can be latched on is during the duration of an initial firing command signal.

  4. Characterization of an Autonomous Non-Volatile Ferroelectric Memory Latch

    NASA Technical Reports Server (NTRS)

    John, Caroline S.; MacLeod, Todd C.; Evans, Joe; Ho, Fat D.

    2011-01-01

    We present the electrical characterization of an autonomous non-volatile ferroelectric memory latch using the principle that when an electric field is applied to a ferroelectriccapacitor,the positive and negative remnant polarization charge states of the capacitor are denoted as either data 0 or data 1. The properties of the ferroelectric material to store an electric polarization in the absence of an electric field make the device non-volatile. Further the memory latch is autonomous as it operates with the ground, power and output node connections, without any externally clocked control line. The unique quality of this latch circuit is that it can be written when powered off. The advantages of this latch over flash memories are: a) It offers unlimited reads/writes b) works on symmetrical read/write cycles. c) The latch is asynchronous. The circuit was initially developed by Radiant Technologies Inc., Albuquerque, New Mexico.

  5. SEU mitigation for half-latches in xilinx virtex FPGAs.

    SciTech Connect

    Graham, P. S.; Caffrey, M. P.; Wirthlin, M. J.; Johnson, D. E.; Rollins, N.

    2003-01-01

    The performance, in-system reprogrammability, flexibility, and reduced costs of SRAM-based field-programmable gate arrays (FPGAs) make them very interesting for high-speed, on-orbit data processing, but, because the current generation of radiation-tolerant SRAM-based FPGAs are derived directly from COTS versions of the chips, their memory structures are still susceptible to single-event upsets (SEUs) . While previous papers have described the SEU characteristics and mitigation techniques for the configuration and user memory structures on the Xilinx Virtex family of FPGAs, we will concentrate on the effects of SEUs on 'half-latch' structures within the Virtex architecture, describe techniques for mitigating these effects, and provide new experimental data which illustrate the effectiveness of one of these mitigation techniques under proton radiation.

  6. Miga Aero Actuator and 2D Machined Mechanical Binary Latch

    NASA Technical Reports Server (NTRS)

    Gummin, Mark A.

    2013-01-01

    actuators. SMA actuators typically perform ideally as latch-release devices, wherein a spring-loaded device is released when the SMA actuator actuates in one direction. But many applications require cycling between two latched states open and closed.

  7. Static internal performance of single-expansion-ramp nozzles with various combinations of internal geometric parameters

    NASA Technical Reports Server (NTRS)

    Re, R. J.; Leavitt, L. D.

    1984-01-01

    The effects of five geometric design parameters on the internal performance of single-expansion-ramp nozzles were investigated at nozzle pressure ratios up to 10 in the static-test facility of the Langley 16-Foot Transonic Tunnel. The geometric variables on the expansion-ramp surface of the upper flap consisted of ramp chordal angle, ramp length, and initial ramp angle. On the lower flap, the geometric variables consisted of flap angle and flap length. Both internal performance and static-pressure distributions on the centerlines of the upper and lower flaps were obtained for all 43 nozzle configurations tested.

  8. Performance comparison between static and dynamic cardiac CT on perfusion quantitation and patient classification tasks

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2015-03-01

    Cardiac CT acquisitions for perfusion assessment can be performed in a dynamic or static mode. In this simulation study, we evaluate the relative classification and quantification performance of these modes for assessing myocardial blood flow (MBF). In the dynamic method, a series of low dose cardiac CT acquisitions yields data on contrast bolus dynamics over time; these data are fit with a model to give a quantitative MBF estimate. In the static method, a single CT acquisition is obtained, and the relative CT numbers in the myocardium are used to infer perfusion states. The static method does not directly yield a quantitative estimate of MBF, but these estimates can be roughly approximated by introducing assumed linear relationships between CT number and MBF, consistent with the ways such images are typically visually interpreted. Data obtained by either method may be used for a variety of clinical tasks, including 1) stratifying patients into differing categories of ischemia and 2) using the quantitative MBF estimate directly to evaluate ischemic disease severity. Through simulations, we evaluate the performance on each of these tasks. The dynamic method has very low bias in MBF estimates, making it particularly suitable for quantitative estimation. At matched radiation dose levels, ROC analysis demonstrated that the static method, with its high bias but generally lower variance, has superior performance in stratifying patients, especially for larger patients.

  9. Static internal performance characteristics of two thrust reverser concepts for axisymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Leavitt, L. D.; Re, R. J.

    1982-01-01

    The statis performance of two axisymmetric nozzle thrust reverser concepts was investigated. A rotating vane thrust reverser represented a concept in which reversing is accomplished upstream of the nozzle throat, and a three door reverser concept provided reversing downstream of the nozzle throat. Nozzle pressure ratio was varied from 2.0 to approximately 6.0. The results of this investigation indicate that both the rotating vane and three door reverser concepts were effective static thrust spoilers with the landing approach nozzle geometry and were capable of providing at least a 50 percent reversal of static thrust when fully deployed with the ground roll nozzle geometry.

  10. 49 CFR 571.113 - Standard No. 113; Hood latch system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Standard No. 113; Hood latch system. 571.113... Motor Vehicle Safety Standards § 571.113 Standard No. 113; Hood latch system. S1. Purpose and scope. This standard establishes the requirement for providing a hood latch system or hood latch systems....

  11. 49 CFR 571.113 - Standard No. 113; Hood latch system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Standard No. 113; Hood latch system. 571.113... Motor Vehicle Safety Standards § 571.113 Standard No. 113; Hood latch system. S1. Purpose and scope. This standard establishes the requirement for providing a hood latch system or hood latch systems....

  12. Static and dynamic performance of notched LDF{trademark}/PEKK composites

    SciTech Connect

    Whitworth, H.A.; Llorente, S.G.; Croman, R.B.

    1993-12-31

    Two different quasi-isotropic layups of carbon fiber reinforced PEKK (poly-ether-ketone-ketone) thermoplastic laminates were subjected to tensile static and tensile fatigue loadings. Some of the samples contained holes to access their notch sensitivity. In addition the AS-4 carbon fiber was of a long discontinuous form (LDF{trademark}) and the performance of the LDF{trademark} was compared with continuous fiber reinforcement. The two layups were: (90,0,{+-}45)s and (90,{+-}45,0)s and the specimens had either no hole, one hole, or three holes. These were tested for ultimate static strength and fatigued in tension at approximately 70% of static ultimate strength with R=0.1. The results were compared as to layup, fiber reinforcement type, and notch configuration. In addition the results obtained were compared with some previous work where the layups were (0,90,{+-}45)s and (0,{+-}45,90)s.

  13. Dynamic performance and control of a static var generator using cascade multilevel inverters

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A cascade multilevel inverter is proposed for static VAR shifting, compensation/generation applications. The new cascade M-level inverter consists of (M-1)/2 single-phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle. It can eliminate the need for transformers in multipulse inverters. A prototype static VAR generator (SVG) system using 11- level cascade inverter (21-level line-to-line voltage waveform) has been built. The output voltage waveform is equivalent to that of a 60- pulse inverter. This paper focuses on dynamic performance of the cascade inverter based SVG system. Control schemes are proposed to achieve a fast response which is impossible for a conventional static VAR compensator (SVC). Analytical, simulated and experimental results show the superiority of the proposed SVG system.

  14. Comparison of User Performance with Interactive and Static 3d Visualization - Pilot Study

    NASA Astrophysics Data System (ADS)

    Herman, L.; Stachoň, Z.

    2016-06-01

    Interactive 3D visualizations of spatial data are currently available and popular through various applications such as Google Earth, ArcScene, etc. Several scientific studies have focused on user performance with 3D visualization, but static perspective views are used as stimuli in most of the studies. The main objective of this paper is to try to identify potential differences in user performance with static perspective views and interactive visualizations. This research is an exploratory study. An experiment was designed as a between-subject study and a customized testing tool based on open web technologies was used for the experiment. The testing set consists of an initial questionnaire, a training task and four experimental tasks. Selection of the highest point and determination of visibility from the top of a mountain were used as the experimental tasks. Speed and accuracy of each task performance of participants were recorded. The movement and actions in the virtual environment were also recorded within the interactive variant. The results show that participants deal with the tasks faster when using static visualization. The average error rate was also higher in the static variant. The findings from this pilot study will be used for further testing, especially for formulating of hypotheses and designing of subsequent experiments.

  15. Heritage Adoption Lessons Learned: Cover Deployment and Latch Mechanism

    NASA Technical Reports Server (NTRS)

    Wincentsen, James

    2006-01-01

    This viewgraph presentation reviews the lessons learned from heritage adoption designs. A general overview of cover deployment hardware that includes the three mechanisms of latch, hinge, and energy absorbers are also discussed.

  16. Generating functionals for autonomous latching dynamics in attractor relict networks

    PubMed Central

    Linkerhand, Mathias; Gros, Claudius

    2013-01-01

    Coupling local, slowly adapting variables to an attractor network allows to destabilize all attractors, turning them into attractor ruins. The resulting attractor relict network may show ongoing autonomous latching dynamics. We propose to use two generating functionals for the construction of attractor relict networks, a Hopfield energy functional generating a neural attractor network and a functional based on information-theoretical principles, encoding the information content of the neural firing statistics, which induces latching transition from one transiently stable attractor ruin to the next. We investigate the influence of stress, in terms of conflicting optimization targets, on the resulting dynamics. Objective function stress is absent when the target level for the mean of neural activities is identical for the two generating functionals and the resulting latching dynamics is then found to be regular. Objective function stress is present when the respective target activity levels differ, inducing intermittent bursting latching dynamics. PMID:23784373

  17. Astronaut James Newman with latch hook for tether device

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut James H. Newman, mission specialist, shows off a latch hook for a tether device used during the STS-51 extravehicular activity (EVA) on September 16, 1993. Newman, on Discovery's middeck, appears surrounded by sleep restraints.

  18. All-optical SOA latch fail-safe alarm system

    NASA Astrophysics Data System (ADS)

    McAulay, Alastair D.

    2004-11-01

    Emergency alarm systems, for example, that switch off critical processes in process plant, are vulnerable to deliberate or accidental sabotage through coupling of electromagnetic pulses (EMP) to wires and/or from sparks due to broken wires. A proposed system significantly reduces vulnerability by using a fast all-optical latch in conjunction with an optical sensor and optical fibers. Sparks cannot be created on breaking an optical beam and electromagnetic field transients have negligible effect on optical signals. The optical latch uses optical semiconductor amplifiers (SOAs) configured to form a flip-flop. The flip-flop latches after the occurrence of an intrusion that may be as short as a few nanoseconds, much faster than most environmental changes occur. Detection of an emergency or any break in connections causes the light to drop, triggering the alarm. Computer simulation shows that the all-optical latch is fast and effective.

  19. Comparative research on “high currents” induced by single event latch-up and transient-induced latch-up

    NASA Astrophysics Data System (ADS)

    Chen, Rui; Han, Jian-Wei; Zheng, Han-Sheng; Yu, Yong-Tao; Shangguang, Shi-Peng; Feng, Guo-Qiang; Ma, Ying-Qi

    2015-04-01

    By using the pulsed laser single event effect facility and electro-static discharge (ESD) test system, the characteristics of the “high current”, relation with external stimulus and relevance to impacted modes of single event latch-up (SEL) and transient-induced latch-up (TLU) are studied, respectively, for a 12-bit complementary metal-oxide semiconductor (CMOS) analog-to-digital converter. Furthermore, the sameness and difference in physical mechanism between “high current” induced by SEL and that by TLU are disclosed in this paper. The results show that the minority carrier diffusion in the PNPN structure of the CMOS device which initiates the active parasitic NPN and PNP transistors is the common reason for the “high current” induced by SEL and for that by TLU. However, for SEL, the minority carrier diffusion is induced by the ionizing radiation, and an underdamped sinusoidal voltage on the supply node (the ground node) is the cause of the minority carrier diffusion for TLU. Project supported by the National Natural Science Foundation of China (Grant No. 41304148).

  20. Acute effects of static stretching on squat jump performance at different knee starting angles.

    PubMed

    La Torre, Antonio; Castagna, Carlo; Gervasoni, Elisa; Cè, Emiliano; Rampichini, Susanna; Ferrarin, Maurizio; Merati, Giampiero

    2010-03-01

    The purpose of this study was to examine the effects of static stretching on leg extensor muscles during squat jump (SJ) at different knee starting angles. Seventeen male subjects (23 +/- 3 years, 179 +/- 5 cm, and 74 +/- 6 kg) performed on a force platform 2 series (preceded or not [control condition] by 10-minute static stretching of quadriceps and triceps surae muscles) of SJs at different knee starting angles: 50 degrees, 70 degrees, 90 degrees, and 110 degrees. Squat jump height, peak force, maximal acceleration, velocity, and power were calculated for each jump. The angle that maximized power development was obtained from the power-angle relationship. The SJ height, peak force, and maximal velocity increased according to angle amplitude in both control and stretching conditions (p < 0.01), performance being significantly lower in the stretching condition (p < 0.01). Peak power was obtained at 90 degrees in both control and stretching conditions, but was significantly lower (p < 0.01) after stretching. These results suggest that an acute bout of static stretching reduces power and force development during SJ, decrements being significantly higher at lower knee starting angles. Therefore, the use of static stretching may be questionable in those power activities requiring maximal power output at knee angles near full extension. PMID:20145567

  1. Bench-level characterization of a CMOS standard-cell D-latch using alpha-particle sensitive test circuits

    SciTech Connect

    Blaes, B.R.; Soli, G.A.; Buehler, M.G. )

    1991-12-01

    This paper describes a methodology for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-{mu}m n-well CMOS 4k-bit test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 {mu}m was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 Mev cm{sup 2}/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV cm{sup 2}/mg was determined.

  2. Bench-level characterization of a CMOS standard-cell D-latch using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Blaes, B. R.; Soli, G. A.; Buehler, M. G.

    1991-01-01

    A methodology is described for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-micron n-well CMOS 4-kb test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 micron was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 MeV sq cm/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV sq cm/mg was determined.

  3. Noise and static performance characteristics of a STOL aircraft jet flap

    NASA Technical Reports Server (NTRS)

    Harkonen, D. L.; Mcbride, J. F.; Okeefe, J. V.

    1974-01-01

    Static noise and performance tests were conducted on a 1/4-scale jet flap model with a multilobe nozzle of array area ratio of 2.7. The model nozzle and flap tested were a two-dimensional section of a distributed blowing system similar to previously investigated augmentor wing systems without the upper shroud and intake door. Noise data were measured with the nozzle alone and also during attached flow conditions with the flap at two turning angles representing takeoff and approach conditions. The noise data are scaled to a 200,000-lb TOGW four-engine airplane and are presented in terms of perceived noise level and one-third octave band sound pressure level. Comparisons are made with the noise levels produced by an augmentor wing airplane fitted with a three-element acoustically lined augmentor flap. The static performance is presented in terms of thrust recovery and effective turning angle.

  4. Static internal performance of an axisymmetric nozzle with multiaxis thrust-vectoring capability

    NASA Technical Reports Server (NTRS)

    Carson, George T., Jr.; Capone, Francis J.

    1991-01-01

    An investigation was conducted in the static test facility of the Langley 16 Foot Transonic Tunnel in order to determine the internal performance characteristics of a multiaxis thrust vectoring axisymmetric nozzle. Thrust vectoring for this nozzle was achieved by deflection of only the divergent section of this nozzle. The effects of nozzle power setting and divergent flap length were studied at nozzle deflection angles of 0 to 30 at nozzle pressure ratios up to 8.0.

  5. Effects of exhaustive dumbbell exercise after isokinetic eccentric damage: recovery of static and dynamic muscle performance.

    PubMed

    Sakamoto, Akihiro; Maruyama, Takeo; Naito, Hisashi; Sinclair, Peter James

    2009-12-01

    This study examined the recovery of static and dynamic muscle performance after eccentric damage with and without repeated exercise, using different exercise modes between the initial and subsequent exercise bouts. Twelve nonweight-trained adults performed both control and repeated exercise conditions. Soreness, limb circumference, static joint angles, creatine kinase (CK), isometric strength, and dynamic muscle performance involving a stretch-shortening cycle (SSC) were monitored for 7 days to evaluate the recovery. After baseline measures, subjects performed 30 maximal isokinetic eccentric contractions (90 degrees/second) of the elbow flexors in each experiment. For the control condition, no treatment was applied. For the repeated exercise condition, 5 sets of arm curls using dumbbells (70% isometric maximal voluntary contraction of each testing day) were performed until failure on days 1, 2, 3, and 5 of recovery. Significant condition vs. time interactions existed in circumference (p = 0.012), static relaxed angle (p = 0.013), isometric strength (p = 0.039), and dynamic extension angle (p = 0.039), suggesting a slightly delayed onset of recovery with the repeated exercise. SSC performance changed more in parallel with soreness after eccentric exercise than did the other measures. It was concluded that the repeated bout effect was present, although slightly reduced, when subsequent exercise performed before recovery was intense and differed in mode from the initial eccentric exercise. Practical applications of this research are that resistance training may be continued after eccentric damage; however, a minor delay in the onset of recovery may occur depending on training modes. Muscle soreness is a good indicator of performance decrement during dynamic movements following eccentric damage. PMID:19910828

  6. Dynamic performance of a static or throwing droplet impact onto a solid substrate with different properties

    NASA Astrophysics Data System (ADS)

    Wu, Jie; Li, Ya-Dong

    2016-03-01

    The dynamic performance of a static or throwing droplet impact onto a solid substrate with different properties is numerically studied in this work. After being released or horizontally thrown out, a two-dimensional droplet can fall freely under gravity. The substrate, which is below the droplet, is either hydrophilic/hydrophobic or inhomogeneous. To conduct numerical simulations, a hybrid method is adopted, in which the flow field is solved by using the lattice Boltzmann method and the interface is captured by solving the Cahn-Hilliard equation directly. Given a fixed distance between the droplet and the substrate (H∗), the effects of Bond number (Bo), Weber number (We), and surface property on the performance of droplet impingement are investigated in detail. With the increase of Bond number, the surface coverage area of a static droplet also increases. A hydrophilic surface or an inhomogeneous surface with small advancing/receding angle difference can lead to the breakup of droplet rim due to the bubble entrapment. Moreover, dependent on the Weber number and the surface property, the leading edge rim of a throwing droplet developing on an inhomogeneous surface may break up before or after it contacts the substrate. As a result, compared to the case of static droplet, the surface coverage area will be reduced due to the diffusion of small droplet segment.

  7. Static internal performance including thrust vectoring and reversing of two-dimensional convergent-divergent nozzles

    NASA Technical Reports Server (NTRS)

    Re, R. J.; Leavitt, L. D.

    1984-01-01

    The effects of geometric design parameters on two dimensional convergent-divergent nozzles were investigated at nozzle pressure ratios up to 12 in the static test facility. Forward flight (dry and afterburning power settings), vectored-thrust (afterburning power setting), and reverse-thrust (dry power setting) nozzles were investigated. The nozzles had thrust vector angles from 0 deg to 20.26 deg, throat aspect ratios of 3.696 to 7.612, throat radii from sharp to 2.738 cm, expansion ratios from 1.089 to 1.797, and various sidewall lengths. The results indicate that unvectored two dimensional convergent-divergent nozzles have static internal performance comparable to axisymmetric nozzles with similar expansion ratios.

  8. Static internal performance of a single expansion ramp nozzle with multiaxis thrust vectoring capability

    NASA Technical Reports Server (NTRS)

    Capone, Francis J.; Schirmer, Alberto W.

    1993-01-01

    An investigation was conducted at static conditions in order to determine the internal performance characteristics of a multiaxis thrust vectoring single expansion ramp nozzle. Yaw vectoring was achieved by deflecting yaw flaps in the nozzle sidewall into the nozzle exhaust flow. In order to eliminate any physical interference between the variable angle yaw flap deflected into the exhaust flow and the nozzle upper ramp and lower flap which were deflected for pitch vectoring, the downstream corners of both the nozzle ramp and lower flap were cut off to allow for up to 30 deg of yaw vectoring. The effects of nozzle upper ramp and lower flap cutout, yaw flap hinge line location and hinge inclination angle, sidewall containment, geometric pitch vector angle, and geometric yaw vector angle were studied. This investigation was conducted in the static-test facility of the Langley 16-Foot Transonic Tunnel at nozzle pressure ratios up to 8.0.

  9. K-band high power latching switch. [communication satellite system

    NASA Technical Reports Server (NTRS)

    Mlinar, M. J.; Piotrowski, W. S.; Raue, J. E.

    1980-01-01

    A 19 GHz waveguide latching switch with a bandwidth of 1400 MHz and an exceptionally low insertion loss of 0.25 dB was demonstrated. The RF and driver ferrites are separate structures and can be optimized individually. This analysis for each structure is separately detailed. Basically, the RF section features a dual turnstile junction. The circulator consists of a dielectric tube which contains two ferrite rods, and a dielectric spacer separating the ferrite parts along the center of symmetry of the waveguide to form two turnstiles. This subassembly is indexed and locked in the center of symmetry of a uniform junction of three waveguides by the metallic transformers installed in the top and bottom walls of the housing. The switching junction and its actuating circuitry met all RF performance objectives and all shock and vibration requirements with no physical damage or performance degradation. It exceeds thermal requirements by operating over a 100 C temperature range (-44 C to +56 C) and has a high power handling capability allowing up to 100 W of CW input power.

  10. Tests of Static Balance Do Not Predict Mobility Performance Following Traumatic Brain Injury

    PubMed Central

    Morris, Meg E.

    2011-01-01

    ABSTRACT Purpose: To investigate the extent to which different single-limb support (SLS) parameters predict mobility performance following traumatic brain injury (TBI). Methods: Seventy-one people with mobility limitations following TBI were assessed for balance and mobility performance in a human movement laboratory. Participants performed a clinical test of static balance that involved balancing in SLS on each leg with eyes open and eyes closed. Mobility performance was measured by self-selected gait speed and performance on the High Level Mobility Scale (HiMAT). Dynamic stability during walking was measured by quantifying lateral centre of mass (COM) displacement, width of base of support, and proportion of double-support stance time. Results: Total static balance scores were strongly correlated with HiMAT scores (r=0.57, p<0.001) and lateral COM displacement (r=−0.51, p<0.001). Despite these strong correlations, however, balance scores explained only 32% of the variance in advanced mobility skills (r2=0.32) and 26% of the variance in lateral COM displacement (r2=0.26). Conclusions: Since mobility performance varied widely for people with similar levels of balance, SLS time was not able to predict dynamic stability during gait, self-selected gait speed, or advanced mobility skills in people with TBI. PMID:22210980

  11. Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses.

    PubMed

    Yapicioglu, Bulent; Colakoglu, Muzaffer; Colakoglu, Zafer; Gulluoglu, Halil; Bademkiran, Fikret; Ozkaya, Ozgur

    2013-12-18

    The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance. PMID:24511340

  12. Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

    PubMed Central

    Yapicioglu, Bulent; Colakoglu, Muzaffer; Colakoglu, Zafer; Gulluoglu, Halil; Bademkiran, Fikret; Ozkaya, Ozgur

    2013-01-01

    The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance. PMID:24511340

  13. High speed non-latching SQUID binary ripple counter

    NASA Astrophysics Data System (ADS)

    Silver, A. H.; Phillips, R. R.; Sandell, R. D.

    1985-03-01

    High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb2O5/PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz.

  14. High speed non-latching squid binary ripple counter

    SciTech Connect

    Silver, A.H.; Phillips, R.R.; Sandell, R.D.

    1985-03-01

    High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb/sub 2/O/sub 5//PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz.

  15. Identifying performing and under performing graphic symbols for verbs and prepositions in animated and static formats: a research note.

    PubMed

    Schlosser, Ralf W; Shane, Howard; Sorce, James; Koul, Rajinder; Bloomfield, Emma

    2011-09-01

    The purpose of this study was to identify graphic symbols for verbs and prepositions that were performing and underperforming in static and animated formats in a recent experiment on the effects of animation on transparency, name agreement, and identification of graphic symbols. Variable-specific criteria were developed in order to define when a symbol is considered to be performing in terms of its transparency, name agreement, and identification accuracy. Additionally, across-variable heuristic criteria were developed that allowed classification of symbols into four categories: (a) performing exceptionally, (b) performing effectively, (c) performing adequately, and (d) performing inadequately. These criteria were applied to 24 symbols for verbs and 8 symbols for prepositions in both animated and static formats. Results indicated that the vast majority of the symbols performed adequately or better while a few did not. Potential reasons as to why some of the symbols may have underperformed are discussed. Where appropriate, implications for modifying existing symbols and future research are drawn. Although the fact that the heuristic criteria were developed post-hoc is discussed as a limitation, the benefits of the proposed categories bode well for future applications. PMID:22008033

  16. Determination of the static performance of a Cuyuna cc model UL-430RR engine

    NASA Technical Reports Server (NTRS)

    Roskam, J.

    1983-01-01

    The results of static performance tests were carried out on an ultralight engine. A Cuyuna 430 cc, 2 stroke, 2 cylinder model was used to measure thrust, torque, propeller RPM, fuel flow, cylinder head temperature, and change in pressure through the propeller. Measurement of each of the above parameters was taken at specific values of RPM. The propeller's RPM's ranged from idle at approximately 750 RPM to a maximum value of 2810 RPM. The test results were then manipulated to obtain thrust coefficient, power coefficient, shaft horse power, and shaft specific fuel consumption.

  17. Static and dynamic posterior cingulate cortex nodal topology of default mode network predicts attention task performance.

    PubMed

    Lin, Pan; Yang, Yong; Jovicich, Jorge; De Pisapia, Nicola; Wang, Xiang; Zuo, Chun S; Levitt, James Jonathan

    2016-03-01

    Characterization of the default mode network (DMN) as a complex network of functionally interacting dynamic systems has received great interest for the study of DMN neural mechanisms. In particular, understanding the relationship of intrinsic resting-state DMN brain network with cognitive behaviors is an important issue in healthy cognition and mental disorders. However, it is still unclear how DMN functional connectivity links to cognitive behaviors during resting-state. In this study, we hypothesize that static and dynamic DMN nodal topology is associated with upcoming cognitive task performance. We used graph theory analysis in order to understand better the relationship between the DMN functional connectivity and cognitive behavior during resting-state and task performance. Nodal degree of the DMN was calculated as a metric of network topology. We found that the static and dynamic posterior cingulate cortex (PCC) nodal degree within the DMN was associated with task performance (Reaction Time). Our results show that the core node PCC nodal degree within the DMN was significantly correlated with reaction time, which suggests that the PCC plays a key role in supporting cognitive function. PMID:25904156

  18. The 727 airplane target thrust reverser static performance model test for refanned JT8D engines

    NASA Technical Reports Server (NTRS)

    Chow, C. T. P.; Atkey, E. N.

    1974-01-01

    The results of a scale model static performance test of target thrust reverser configurations for the Pratt and Whitney Aircraft JT8D-100 series engine are presented. The objective of the test was to select a series of suitable candidate reverser configurations for the subsequent airplane model wind tunnel ingestion and flight controls tests. Test results indicate that adequate reverse thrust performance with compatible engine airflow match is achievable for the selected configurations. Tapering of the lips results in loss of performance and only minimal flow directivity. Door pressure surveys were conducted on a selected number of lip and fence configurations to obtain data to support the design of the thrust reverser system.

  19. Target-acquisition performance in undersampled infrared imagers: static imagery to motion video.

    PubMed

    Krapels, Keith; Driggers, Ronald G; Teaney, Brian

    2005-11-20

    In this research we show that the target-acquisition performance of an undersampled imager improves with sensor or target motion. We provide an experiment designed to evaluate the improvement in observer performance as a function of target motion rate in the video. We created the target motion by mounting a thermal imager on a precision two-axis gimbal and varying the sensor motion rate from 0.25 to 1 instantaneous field of view per frame. A midwave thermal imager was used to permit short integration times and remove the effects of motion blur. It is shown that the human visual system performs a superresolution reconstruction that mitigates some aliasing and provides a higher (than static imagery) effective resolution. This process appears to be relatively independent of motion velocity. The results suggest that the benefits of superresolution reconstruction techniques as applied to imaging systems with motion may be limited. PMID:16318174

  20. Acute effects of dynamic stretching, static stretching, and light aerobic activity on muscular performance in women.

    PubMed

    Curry, Brad S; Chengkalath, Devendra; Crouch, Gordon J; Romance, Michelle; Manns, Patricia J

    2009-09-01

    The purpose of this study was to compare three warm-up protocols--static stretching, dynamic stretching, and light aerobic activity--on selected measures of range of motion and power in untrained females and to investigate the sustained effects at 5 and 30 minutes after warm-up. A total of 24 healthy females (ages 23-29 years) attended one familiarization session and three test sessions on nonconsecutive days within 2 weeks. A within-subject design protocol with the testing investigators blinded to the subjects' warm-up was followed. Each session started with 5 minutes of light aerobic cycling followed by pretest baseline measures. Another 5 minutes of light aerobic cycling was completed and followed by one of the three randomly selected warm-up interventions (static stretching, dynamic stretching, or light aerobic activity). The following posttest outcome measures were collected 5 and 30 minutes following the intervention: modified Thomas test, countermovement jump, and isometric time to peak force knee extension measured by dynamometer. Analysis of the data revealed significant time effects on range of motion and countermovement jump changes. No significant differences (p > 0.05) were found between the warm-up conditions on any of the variables. The variation in responses to warm-up conditions emphasizes the unique nature of individual reactions to different warm-ups; however, there was a tendency for warm-ups with an active component to have beneficial effects. The data suggests dynamic stretching has greater applicability to enhance performance on power outcomes compared to static stretching. PMID:19675479

  1. Effect of Eccentricity on the Static and Dynamic Performance of a Turbulent Hybrid Bearing

    NASA Technical Reports Server (NTRS)

    Sanandres, Luis A.

    1991-01-01

    The effect of journal eccentricity on the static and dynamic performance of a water lubricated, 5-recess hybrid bearing is presented in detail. The hydrostatic bearing has been designed to operate at a high speed and with a large level of external pressurization. The operating conditions determine the flow in the bearing to be highly turbulent and strongly dominated by fluid inertia effects. The analysis covers the spectrum of journal center displacements directed towards the middle of a recess and towards the mid-land portion between two consecutive recesses. Predicted dynamic force coefficients are uniform for small to moderate eccentricities. For large journal center displacements, fluid cavitation and recess position determine large changes in the bearing dynamic performance. The effect of fluid inertia force coefficients on the threshold speed of instability and whirl ratio of a single mass flexible rotor is discussed.

  2. Static performance and noise tests on a thrust reverser for an augmentor wing aircraft

    NASA Technical Reports Server (NTRS)

    Harkonen, D. L.; Marrs, C. C.; Okeefe, J. V.

    1974-01-01

    A 1/3 scale model static test program was conducted to measure the noise levels and reverse thrust performance characteristics of wing-mounted thrust reverser that could be used on an advanced augmentor wing airplane. The configuration tested represents only the most fundamental designs where installation and packaging restraints are not considered. The thrust reverser performance is presented in terms of horizontal, vertical, and resultant effectiveness ratios and the reverser noise is compared on the basis of peak perceived noise level (PNL) and one-third octave band data (OASPL). From an analysis of the model force and acoustic data, an assessment is made on the stopping distance versus noise for a 90,900 kg (200,000 lb) airplane using this type of thrust reverser.

  3. Non-Contacting Finger Seals Static Performance Test Results at Ambient and High Temperatures

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2016-01-01

    The non-contacting finger seal is an advanced seal concept with potential to reduce specific fuel consumption in gas turbine engines by 2 to 3 with little to no wear of the seal or rotor. Static performance tests and bind-up tests of eight different non-contacting finger seal configurations were conducted in air at pressure differentials up to 689.4 kPa and temperatures up to 922 K. Four of the seals tested were designed to have lift pads concentric to a herringbone-grooved rotor which generates hydrodynamic lift when rotating. The remaining seals were tested with a smooth rotor; one seal had a circumferential taper and one had an axial taper on the lift pad inner diameter to create hydrodynamic lift during rotation. The effects of the aft finger axial thickness and of the forward finger inner diameter on leakage performance were investigated as well and compared to analytical predictions.

  4. Non-Contacting Finger Seals Static Performance Test Results at Ambient and High Temperatures

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2016-01-01

    The non-contacting finger seal is an advanced seal concept with potential to reduce specific fuel consumption in gas turbine engines by 2 to 3 percent with little to no wear of the seal or rotor. Static performance tests and bind-up tests of eight different non-contacting finger seal configurations were conducted in air at pressure differentials up to 689.4 kPa and temperatures up to 922 K. Four of the seals tested were designed to have lift pads concentric to a herringbone-grooved rotor which generates hydrodynamic lift when rotating. The remaining seals were tested with a smooth rotor; one seal had a circumferential taper and one had an axial taper on the lift pad inner diameter to create hydrodynamic lift during rotation. The effects of the aft finger axial thickness and of the forward finger inner diameter on leakage performance were investigated as well and compared to analytical predictions.

  5. 49 CFR 236.763 - Locking, latch operated.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locking, latch operated. 236.763 Section 236.763 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL...

  6. Static and Dynamic Performance of Newly Developed ITER Relevant Insulation Systems after Neutron Irradiation

    NASA Astrophysics Data System (ADS)

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

    2006-03-01

    Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation-hard resin systems are of special interest. In this study various R-glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1×1022 m-2 (E>0.1 MeV). Short-beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension-tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the static and dynamic material behavior was investigated as well.

  7. Aerodynamic and Acoustic Performance of Two Choked-Flow Inlets Under Static Conditions

    NASA Technical Reports Server (NTRS)

    Miller, B. A.; Abbott, J. M.

    1972-01-01

    Tests were conducted to determine the aerodynamic and acoustic performance of two choking flow inlets under static conditions. One inlet choked the flow in the cowl throat by an axial translation of the inlet centerbody. The other inlet employed a translating grid of airfoils to choke the flow. Both inlets were sized to fit a 13.97 cm diameter fan with a design weight flow of 2.49 kg/sec. The inlets were operated in both the choked and unchoked modes over a range of weight flows. Measurements were made of inlet pressure recovery, flow distortion, surface static pressure distribution, and fan noise suppression. Choking of the translating centerbody inlet reduced blade passing frequency noise by 29 db while yielding a total pressure recovery of 0.985. Noise reductions were also measured at 1/3-octave band center frequencies of 2500, 5000, and 20,000 cycles. The translating grid inlet gave a total pressure recovery of 0.968 when operating close to the choking weight flow. However, an intermittent high intensity noise source was encountered with this inlet that precluded an accurate measurement of inlet noise suppression.

  8. Static and Dynamic Performance of Newly Developed ITER Relevant Insulation Systems after Neutron Irradiation

    SciTech Connect

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

    2006-03-31

    Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation-hard resin systems are of special interest. In this study various R-glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1x1022 m-2 (E>0.1 MeV). Short-beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension-tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the static and dynamic material behavior was investigated as well.

  9. Static and dynamic electrical performances of STI thin-SOI power LDMOS transistors

    NASA Astrophysics Data System (ADS)

    Cortes, I.; Fernández-Martínez, P.; Flores, D.; Hidalgo, S.; Rebollo, J.

    2008-09-01

    The benefits of applying the shallow trench isolation (STI) concept to a higher voltage thin-SOI laterally diffused metal oxide semiconductor (LDMOS) (in the range of 80 V) are analysed in this paper by means of 2D technology computer-aided design (TCAD) numerical simulations. The TCAD simulation results allow comparing the electrical performance of the studied STI LDMOS structure with that of a conventional LDMOS in terms of the main static (breakdown voltage (VBR) and specific on-state resistance (RON-sp)) and dynamic (gate-drain capacitance (CGD) and cut-off frequency (fT)) characteristics. Moreover, the impact of the STI length (LSTI) and thickness (TSTI), and the N-drift implantation energy on the electrical characteristics is considered in detail. On the other hand, the STI block helps to move the harmful high electric field further away from the silicon surface, thus minimizing gate-oxide degradation by hot carriers.

  10. Performance, static stability, and control effectiveness of a parametric space shuttle launch vehicle

    NASA Technical Reports Server (NTRS)

    Buchholz, R. E.; Gamble, M.

    1972-01-01

    This test was run as a continuation of a prior investigation of aerodynamic performance and static stability tests for a parametric space shuttle launch vehicle. The purposes of this test were: (1) to obtain a more complete set of data in the transonic flight region, (2) to investigate new H-0 tank noseshapes and tank diameters, (3) to obtain control effectiveness data for the orbiter at 0 degree incidence and with a smaller diameter H-0 tank, and (4) to determine the effects of varying solid rocket motor-to-H0 tank gap size. Experimental data were obtained for angles of attack from -10 to +10 degrees and for angles of sideslip from +10 to -10 degrees at Mach numbers ranging from .6 to 4.96.

  11. Enhancing the force capability of permanent magnet latching actuators for electromechanical valve actuation systems

    NASA Astrophysics Data System (ADS)

    Rens, J.; Clark, R. E.; Jewell, G. W.; Howe, D.

    2005-05-01

    This article introduces a topology of parallel-polarized permanent magnet latching actuator for use in electromagnetic valve actuation systems for internal combustion engines. The actuator has a number of advantages over reluctance actuators, commonly employed in such systems, in terms of reduced starting currents and fail-safe capability. The influence of a number of design features on actuator performance, such as tooth tapering, additional magnets to improve the main magnet flux path and prevent the onset of saturation, and mechanical clearances required to protect the permanent magnet from shock loads are investigated. The design study findings are verified by measurements on a prototype actuator.

  12. Fasting improves static apnea performance in elite divers without enhanced risk of syncope.

    PubMed

    Schagatay, Erika; Lodin-Sundström, Angelica

    2014-01-01

    In competitive apnea divers, the nutritional demands may be essentially different from those of, for example, endurance athletes, where energy resources need to be maximised for successful performance. In competitive apnea, the goal is instead to limit metabolism, as the length of the sustainable apneic period will depend to a great extent on minimising oxygen consumption. Many but not all elite divers fast before performing static apnea in competition. This may increase oxygen consumption as mainly lipid stores are metabolised but could also have beneficial effects on apneic duration. Our aim was to determine the effect of over-night fasting on apnea performance. Six female and seven male divers performed a series of three apneas after eating and fasting, respectively. The series consisted of two 2-min apneas spaced by 3 min rest and, after 5 min rest, one maximal effort apnea. Apneas were performed at supine rest and preceded by normal respiration and maximal inspiration. Mean (± SD) time since eating was 13 h (± 2 h 43 min) for the fasting and 1 h 34 min (± 33 min) for the eating condition (P < 0.001). Mean blood glucose was 5.1 (± 0.4) mmol/L after fasting and 5.9 (± 0.7) mmol/L after eating (P<0.01). Lung volumes were similar in both conditions (NS). For the 2-min apneas, nadir SaO2 during fasting was 95 (± 1)% and 92 (± 2)% (P < 0.001) on eating and ETCO2 was lower in the fasting condition (P < 0.01) while heart rate (HR) during apnea was 74 (± 10) bpm for fasting and 80 (± 10) bpm for eating conditions (P < 0.01). Maximal apnea durations were 4 min 41 s (± 43 s) during fasting and 3 min 51 s (± 37 s) after eating (P < 0.001), and time without respiratory contractions was 31 s (25%) longer after fasting (P < 0.01). At maximal apnea termination, SaO2 and ETCO2 were similar in both conditions (NS) and apneic HR was 63 (± 9) bpm for fasting and 70 (± 10) bpm for eating (P < 0.01). The 22% longer apnea duration after fasting with analogous end apnea

  13. The effect of motor imagery and static stretching on anaerobic performance in trained cyclists.

    PubMed

    Kingsley, J Derek; Zakrajsek, Rebecca A; Nesser, Thomas W; Gage, Matthew J

    2013-01-01

    Athletes perform many different protocols as part of their warm-up routine before competition. Stretching has been suggested to decrease force and power production, whereas motor imagery (MI), the visualization of simple or complex motor activities in the absence of physical movement, may increase force and power production in young healthy individuals. Few studies have investigated either of these in trained individuals. No studies have compared the effects of static stretching (SS) with MI on anaerobic performance in trained cyclists. The purpose of this study was to examine the effects of SS compared with MI and quiet rest (QR) on anaerobic performance in trained cyclists. Thirteen trained cyclists (9 men: 4 women; aged 21 ± 2 years) were assessed for height (1.76 ± 0.07 m), weight (73.4 ± 13 kg), % body fat (10.8 ± 6.2%), and maximal oxygen consumption (V[Combining Dot Above]O(2)max of 42.0 ± 5.6 ml·kg(-1)·min(-1)) on a cycle ergometer. The participants performed 3 randomized sessions consisting of cycling for 30 minutes at 65% of V[Combining Dot Above]O(2)max before undergoing 16 minutes of SS, MI, or QR followed by an anaerobic performance test. The SS consisted of 3 sets of 30-second stretches of the hamstrings, quadriceps, hip flexors, and piriformis. Imagery was based on the physical, environmental, task, learning, emotion, and perspective approach and was conducted by a trained technician. Both relative and absolute powers, and peak revolutions per minute, were quantified using the Wingate anaerobic threshold test. No significant interactions existed among SS, MI, and QR for relative peak power, absolute peak power, or peak RPM. In disagreement with current literature, this study suggests that neither SS nor a single session of MI immediately affect anaerobic performance in trained cyclists. If an event is <30 seconds, then SS or MI may not affect performance. PMID:22476165

  14. Static performance investigation of a skewed-throat multiaxis thrust-vectoring nozzle concept

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    1994-01-01

    The static performance of a jet exhaust nozzle which achieves multiaxis thrust vectoring by physically skewing the geometric throat has been characterized in the static test facility of the 16-Foot Transonic Tunnel at NASA Langley Research Center. The nozzle has an asymmetric internal geometry defined by four surfaces: a convergent-divergent upper surface with its ridge perpendicular to the nozzle centerline, a convergent-divergent lower surface with its ridge skewed relative to the nozzle centerline, an outwardly deflected sidewall, and a straight sidewall. The primary goal of the concept is to provide efficient yaw thrust vectoring by forcing the sonic plane (nozzle throat) to form at a yaw angle defined by the skewed ridge of the lower surface contour. A secondary goal is to provide multiaxis thrust vectoring by combining the skewed-throat yaw-vectoring concept with upper and lower pitch flap deflections. The geometric parameters varied in this investigation included lower surface ridge skew angle, nozzle expansion ratio (divergence angle), aspect ratio, pitch flap deflection angle, and sidewall deflection angle. Nozzle pressure ratio was varied from 2 to a high of 11.5 for some configurations. The results of the investigation indicate that efficient, substantial multiaxis thrust vectoring was achieved by the skewed-throat nozzle concept. However, certain control surface deflections destabilized the internal flow field, which resulted in substantial shifts in the position and orientation of the sonic plane and had an adverse effect on thrust-vectoring and weight flow characteristics. By increasing the expansion ratio, the location of the sonic plane was stabilized. The asymmetric design resulted in interdependent pitch and yaw thrust vectoring as well as nonzero thrust-vector angles with undeflected control surfaces. By skewing the ridges of both the upper and lower surface contours, the interdependency between pitch and yaw thrust vectoring may be eliminated

  15. Static Thrust and Vectoring Performance of a Spherical Convergent Flap Nozzle with a Nonrectangular Divergent Duct

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    1998-01-01

    The static internal performance of a multiaxis-thrust-vectoring, spherical convergent flap (SCF) nozzle with a non-rectangular divergent duct was obtained in the model preparation area of the Langley 16-Foot Transonic Tunnel. Duct cross sections of hexagonal and bowtie shapes were tested. Additional geometric parameters included throat area (power setting), pitch flap deflection angle, and yaw gimbal angle. Nozzle pressure ratio was varied from 2 to 12 for dry power configurations and from 2 to 6 for afterburning power configurations. Approximately a 1-percent loss in thrust efficiency from SCF nozzles with a rectangular divergent duct was incurred as a result of internal oblique shocks in the flow field. The internal oblique shocks were the result of cross flow generated by the vee-shaped geometric throat. The hexagonal and bowtie nozzles had mirror-imaged flow fields and therefore similar thrust performance. Thrust vectoring was not hampered by the three-dimensional internal geometry of the nozzles. Flow visualization indicates pitch thrust-vector angles larger than 10' may be achievable with minimal adverse effect on or a possible gain in resultant thrust efficiency as compared with the performance at a pitch thrust-vector angle of 10 deg.

  16. Retractable tool bit having latch type catch mechanism

    NASA Technical Reports Server (NTRS)

    Voellmer, George (Inventor)

    1993-01-01

    A retractable tool bit assembly for a tool such as an allen key is presented. The assembly includes one or more spring loaded nestable or telescoping tubular sections together with a catch mechanism for capturing and holding the tool in its retracted position. The catch mechanism consists of a latch mechanism located in a base section and which engages a conically shaped tool head located at the inner end of the tool. The tool head adjoins an eccentric oval type neck portion which extends to a rear lip of the tool head. The latch mechanism releases when the ovular neck portion rotates about the catch members upon actuation of a rotary tool drive motor. When released, all the telescoping sections and the tool extends fully outward to a use position.

  17. Novel latch for adiabatic quantum-flux-parametron logic

    SciTech Connect

    Takeuchi, Naoki Yamanashi, Yuki; Yoshikawa, Nobuyuki; Ortlepp, Thomas

    2014-03-14

    We herein propose the quantum-flux-latch (QFL) as a novel latch for adiabatic quantum-flux-parametron (AQFP) logic. A QFL is very compact and compatible with AQFP logic gates and can be read out in one clock cycle. Simulation results revealed that the QFL operates at 5 GHz with wide parameter margins of more than ±22%. The calculated energy dissipation was only ∼0.1 aJ/bit, which yields a small energy delay product of 20 aJ·ps. We also designed shift registers using QFLs to demonstrate more complex circuits with QFLs. Finally, we experimentally demonstrated correct operations of the QFL and a 1-bit shift register (a D flip-flop)

  18. Unsteady vortex lattice techniques applied to wake formation and performance of the statically thrusting propeller

    NASA Technical Reports Server (NTRS)

    Hall, G. F.

    1975-01-01

    The application is considered of vortex lattice techniques to the problem of describing the aerodynamics and performance of statically thrusting propellers. A numerical lifting surface theory to predict the aerodynamic forces and power is performed. The chordwise and spanwise loading is modelled by bound vortices fixed to a twisted flat plate surface. In order to eliminate any apriori assumptions regarding the wake shape, it is assumed the propeller starts from rest. The wake is generated in time and allowed to deform under its own self-induced velocity field as the motion of the propeller progresses. The bound circulation distribution is then determined with time by applying the flow tangency boundary condition at certain selected control points on the blades. The aerodynamics of the infinite wing and finite wing are also considered. The details of wake formation and roll-up are investigated, particularly the localized induction effect. It is concluded that proper wake roll-up and roll-up rates can be established by considering the details of motion at the instant of start.

  19. Heritage Adoption Lessons Learned: Cover Deployment and Latch Mechanism

    NASA Technical Reports Server (NTRS)

    Wincentsen, James

    2006-01-01

    Within JPL, there is a technology thrust need to develop a larger Cover Deployment and Latch Mechanism (CDLM) for future missions. The approach taken was to adopt and scale the CDLM design as used on the Galaxy Evolution Explorer (GALEX) project. The three separate mechanisms that comprise the CDLM will be discussed in this paper in addition to a focus on heritage adoption lessons learned and specific examples. These lessons learned will be valuable to any project considering the use of heritage designs.

  20. Upper Limb Static-Stretching Protocol Decreases Maximal Concentric Jump Performance

    PubMed Central

    Marchetti, Paulo H.; Silva, Fernando H. D. de Oliveira; Soares, Enrico G.; Serpa, Érica P.; Nardi, Priscyla S. M.; Vilela, Guanis de B.; Behm, David G.

    2014-01-01

    The purpose of the present study was to evaluate the acute effects of an upper limb static-stretching (SS) protocol on the maximal concentric jump performance. We recruited 25 young healthy, male, resistance trained individuals (stretched group, n = 15 and control group, n = 10) in this study. The randomized between group experimental protocol consisted of a three trials of maximal concentric jump task, before and after a SS of the upper limb. Vertical ground reaction forces (vGRF) and surface electromyography (sEMG) of both gastrocnemius lateralis (GL) and vastus lateralis (VL) were acquired. An extensive SS was employed consisting of ten stretches of 30 seconds, with 15 seconds of rest, and 70-90% of the point of discomfort (POD). ANOVA (2x2) (group x condition) was used for shoulder joint range of motion (ROM), vGRF and sEMG. A significant interaction for passive ROM of the shoulder joint revealed significant increases between pre- and post-SS protocol (p < 0.001). A significant interaction demonstrated decreased peak force and an increased peak propulsion duration between pre- and post-stretching only for stretch group (p = 0.021, and p = 0.024, respectively. There was a significant main effect between groups (stretch and control) for peak force for control group (p = 0.045). Regarding sEMG variables, there were no significant differences between groups (control versus stretched) or condition (pre-stretching versus post-stretching) for the peak amplitude of RMS and IEMG for both muscles (VL and GL). In conclusion, an acute extensive SS can increase the shoulder ROM, and negatively affect both the propulsion duration and peak force of the maximal concentric jump, without providing significant changes in muscle activation. Key points The jump performance can be affected negatively by an intense extensive static-stretching protocol. An intense acute extensive SS protocol can affect positively the shoulder ROM. The intense acute extensive SS protocol does not

  1. A Note on the Comparative Statics of Pay-for-Performance in Health Care.

    PubMed

    Sherry, Tisamarie B

    2016-05-01

    Pay-for-performance (P4P) is a widely implemented quality improvement strategy in health care that has generated much enthusiasm, but only limited empirical evidence to support its effectiveness. Researchers have speculated that flawed program designs or weak financial incentives may be to blame, but the reason for P4P's limited success may be more fundamental. When P4P rewards multiple services, it creates a special case of the well-known multitasking problem, where incentives to increase some rewarded activities are blunted by countervailing incentives to focus on other rewarded activities: these incentives may cancel each other out with little net effect on quality. This paper analyzes the comparative statics of a P4P model to show that when P4P rewards multiple services in a setting of multitasking and joint production, the change in both rewarded and unrewarded services is generally ambiguous. This result contrasts with the commonly held intuition that P4P should increase rewarded activities. PMID:25728391

  2. A Study of TRMM Static Earth Sensor Performance Using On-Orbit Sensor Data

    NASA Technical Reports Server (NTRS)

    Natanson, Gregory; Glickman, Jonathan

    2000-01-01

    This paper presents the results of a study of the Barnes static Earth sensor assembly (ESA) using on-orbit data collected from the Tropical Rainfall Measuring Mission (TRMM) spacecraft. It is shown that there exist strong correlations between the large penetration angle residuals and the voltages produced by the Offset Radiation Source (ORS). It is conjectured that at certain times in the TRMM orbit the ORS is operating out of its calibrated range, and consequently corrupts the penetration angle information observed and processed by the ESA. The observed yaw drift between Digital Sun Sensor (DSS) observations is shown to be consistent with predictions by a simple roll-yaw coupling computation. This would explain the large drifts seen on TRMM, where the propagation of the yaw angle between DSS updates does not take into account the possibility of a non-zero roll angle error. Finally, the accuracy of the onboard algorithm used when only three of the four quadrants supply valid penetration angles is assessed. In terms of procedures used to perform this study, the analysis of ESA penetration angle residuals is discovered to be a very useful and insightful tool for assessing, the health and functionality of the ESA.

  3. Brush seal leakage performance with gaseous working fluids at static and low rotor speed conditions

    NASA Technical Reports Server (NTRS)

    Carlile, Julie A.; Hendricks, Robert C.; Yoder, Dennis A.

    1992-01-01

    The leakage performance of a brush seal with gaseous working fluids at static and low rotor speed conditions was studied. The leakage results included for air, helium, and carbon dioxide at several bristle/rotor interferences. Also, the effects of packing a lubricant into the bristles and also of reversing the pressure drop across the seal were studied. Results were compared to that of an annular seal at similar operating conditions. In order to generalize the results, they were correlated using corresponding state theory. The brush seal tested had a bore diameter of 3.792 cm (1.4930 in.), a fence height of 0.0635 cm (0.025 in.), and 1800 bristles/cm circumference (4500 bristles/in. circumference). Various bristle/rotor radial interferences were achieved by using a tapered rotor. The brush seal reduced the leakage in comparison to the annular seal, up to 9.5 times. Reversing the pressure drop across the brush seal produced leakage rates approximately the same as that of the annular seal. Addition of a lubricant reduced the leakage by 2.5 times. The air and carbon dioxide data were successfully correlated using corresponding state theory. However, the helium data followed a different curve than the air and carbon dioxide data.

  4. Static Internal Performance of a Two-Dimensional Convergent-Divergent Nozzle with External Shelf

    NASA Technical Reports Server (NTRS)

    Lamb, Milton; Taylor, John G.; Frassinelli, Mark C.

    1996-01-01

    An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance of a two-dimensional convergent-divergent nozzle. The nozzle design was tested with dry and afterburning throat areas, which represent different power settings and three expansion ratios. For each of these configurations, three trailing-edge geometries were tested. The baseline geometry had a straight trailing edge. Two different shaping techniques were applied to the baseline nozzle design to reduce radar observables: the scarfed design and the sawtooth design. A flat plate extended downstream of the lower divergent flap trailing edge parallel to the model centerline to form a shelf-like expansion surface. This shelf was designed to shield the plume from ground observation (infrared radiation (IR) signature suppression). The shelf represents the part of the aircraft structure that might be present in an installed configuration. These configurations were tested at nozzle pressure ratios from 2.0 to 12.0.

  5. Brush seal leakage performance with gaseous working fluids at static and low rotor speed conditions

    NASA Technical Reports Server (NTRS)

    Carlile, Julie A.; Hendricks, Robert C.; Yoder, Dennis A.

    1992-01-01

    The leakage performance of a brush seal with gaseous working fluids at static and low rotor speed conditions was studied. The leakage results are included for air, helium, and carbon dioxide at several bristle/rotor interferences. Also, the effects of packing a lubricant into the bristles and also of reversing the pressure drop across the seal were studied. Results were compared to that of an annular seal at similar operating conditions. In order to generalize the results, they were correlated using corresponding state theory. The brush seal tested had a bore diameter of 3.792 cm (1.4930 in), a fence height of 0.0635 cm (0.025 in), and 1800 bristles/cm circumference (4500 bristles/in circumference). Various bristle/rotor radial interferences were achieved by using a tapered rotor. The brush seal reduced the leakage in comparison to the annular seal, up to 9.5 times. Reversing the pressure drop across the brush seal produced leakage rates approx. the same as that of the annular seal. Addition of a lubricant reduced the leakage by 2.5 times. The air and carbon dioxide data were successfully correlated using corresponding state theory. However, the helium data followed a different curve than the air and carbon dioxide data.

  6. Static and Wind Tunnel Aero-Performance Tests of NASA AST Separate Flow Nozzle Noise Reduction Configurations

    NASA Technical Reports Server (NTRS)

    Mikkelsen, Kevin L.; McDonald, Timothy J.; Saiyed, Naseem (Technical Monitor)

    2001-01-01

    This report presents the results of cold flow model tests to determine the static and wind tunnel performance of several NASA AST separate flow nozzle noise reduction configurations. The tests were conducted by Aero Systems Engineering, Inc., for NASA Glenn Research Center. The tests were performed in the Channels 14 and 6 static thrust stands and the Channel 10 transonic wind tunnel at the FluiDyne Aerodynamics Laboratory in Plymouth, Minnesota. Facility checkout tests were made using standard ASME long-radius metering nozzles. These tests demonstrated facility data accuracy at flow conditions similar to the model tests. Channel 14 static tests reported here consisted of 21 ASME nozzle facility checkout tests and 57 static model performance tests (including 22 at no charge). Fan nozzle pressure ratio varied from 1.4 to 2.0, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Channel 10 wind tunnel tests consisted of 15 tests at Mach number 0.28 and 31 tests at Mach 0.8. The sting was checked out statically in Channel 6 before the wind tunnel tests. In the Channel 6 facility, 12 ASME nozzle data points were taken and 7 model data points were taken. In the wind tunnel, fan nozzle pressure ratio varied from 1.73 to 2.8, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Test results include thrust coefficients, thrust vector angle, core and fan nozzle discharge coefficients, total pressure and temperature charging station profiles, and boat-tail static pressure distributions in the wind tunnel.

  7. Static internal performance of single-expansion-ramp nozzles with thrust-vectoring capability up to 60 deg

    NASA Technical Reports Server (NTRS)

    Berrier, B. L.; Leavitt, L. D.

    1984-01-01

    An investigation has been conducted at static conditions (wind off) in the static-test facility of the Langley 16-Foot Transonic Tunnel. The effects of geometric thrust-vector angle, sidewall containment, ramp curvature, lower-flap lip angle, and ramp length on the internal performance of nonaxisymmetric single-expansion-ramp nozzles were investigated. Geometric thrust-vector angle was varied from -20 deg. to 60 deg., and nozzle pressure ratio was varied from 1.0 (jet off) to approximately 10.0.

  8. Static internal performance of convergent single-expansion-ramp nozzles with various combinations of internal geometric parameters

    NASA Technical Reports Server (NTRS)

    Bare, E. Ann; Capone, Francis J.

    1989-01-01

    An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel to determine the effects of five geometric design parameters on the internal performance of convergent single expansion ramp nozzles. The effects of ramp chordal angle, initial ramp angle, flap angle, flap length, and ramp length were determined. All nozzles tested has a nominally constant throat area and aspect ratio. Static pressure distributions along the centerlines of the ramp and flap were also obtained for each configuration. Nozzle pressure ratio was varied up to 10.0 for all configurations.

  9. Performance comparison of fully adaptive and static passive polarimetric imagers in the presence of intensity and polarization contrast.

    PubMed

    Goudail, François; Boffety, Matthieu

    2016-09-01

    We address the comparison of contrast improvement obtained with a fully adaptive polarimetric imager and the best channel of a static polarimetric imager in the presence of both intensity and polarization differences between the target and the background. We develop an in-depth quantitative study of the performance loss incurred by a static imager compared to a fully adaptive one in this case. These results are useful to make a well-informed choice between these two polarimetric imaging architectures in a given application. PMID:27607513

  10. Neutron-induced latch-up immunity in metal gate CMOS integrated circuits

    SciTech Connect

    Barnes, C.E.; Rollins, J.G.; Hachey, D.

    1987-12-01

    Neutron-induced latch-up immunity has been studied in metal gate CMOS integrated circuits as a function of neutron fluence by measuring both the current gain products (beta product) of parasitic NPN and PNP transistors, and the flash x-ray latch-up thresholds prior to and following irradiation and subsequent stabilization anneal. Correlations between the actual latch-up thresholds and the measured beta products are established for the three part types investigated. These correlations indicate that the measurement of beta products on judiciously chosen parasitic transistors is a viable technique for estimating latch-up susceptibility when the observed margin is substantial.

  11. Remote tong/tool latch and storage bracket for an advanced servo-manipulator

    DOEpatents

    Nicholson, John R.

    1990-01-01

    An arrangement for stowing releasable end effectors for manipulator arms wherein the end effector includes a releasable latch mechanism for connecting the end effector to the manipulator arm, and a storage holder is provided which includes an arrangement for actuating the latch mechanism as the end effector is moved into and out of the holder by the action of the manipulator arm.

  12. Planar latch-up microactuator driven by thermoelastic force

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Hyun; Lee, Myung-Lae; Jang, Won-Ick; Choi, Chang-Auck; Kim, Youn Tae

    2000-08-01

    We designed and fabricated a planar-type thermoelastic microactuator with a latch-up operation for optical switching. Latch-up actuation is prerequisite to implement an optical switch with low power consumption and high reliability. The proposed microactuator consists of four cantilever-shaped thermal actuators, four displacement linkages, two shallow arch-shaped leaf springs, a mobile shuttle mass with a micromirror, and four elastic boundaries. The planar microactuator consists of phosphorous-doped 12 micrometers -thick polysilicon as a structural layer and LTO (Low Temperature Oxide) of 3 micrometers thickness as a sacrificial layer on polysilicon substrate. The experimental displacement of the microactuator was more than 21 micrometers at 10V input voltage for the prototype of a thermoelastic microactuator. The frequency response for square wave input was measured up to 50Hz, which was the highest frequency we can detect using optical microscope for now. The proposed microactuators have advantages of easy assembly with other optical component by way of fiber alignment in the substrate plane, and its fabrication process features simplicity while retaining batch-fabrication economy.

  13. Magnetically coupled quantum-flux-latch with wide operation margins

    NASA Astrophysics Data System (ADS)

    Tsuji, Naoki; Takeuchi, Naoki; Narama, Tatsuya; Ortlepp, Thomas; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2015-11-01

    We have been developing adiabatic quantum-flux-parametron (AQFP) circuits as an ultra-low-power superconductor logic for energy-efficient computing. In a previous study, we proposed and demonstrated a quantum-flux-latch (QFL), which is a compact and compatible latch for AQFP logic. The QFL is composed of an AQFP buffer gate and a storage loop, which are directly connected to each other. However, the operation margins were not sufficiently wide due to a trade-off between the operation margins of the storage loop and that of the buffer gate. In this present study, we propose a magnetically coupled QFL (MC-QFL), where the storage loop and the buffer gate are physically separated and magnetically coupled to each other to eliminate the trade-off in the operation margins. The simulation results showed that the critical parameter margin of the MC-QFL is twice as large as that of the previously designed QFL. For comparison, we fabricated and demonstrated both the previously designed QFL and the newly designed MC-QFL. The measurement results showed that the MC-QFL has wider operation margins compared with the previously designed QFL.

  14. Modeling the Energy Performance of Event-Driven Wireless Sensor Network by Using Static Sink and Mobile Sink

    PubMed Central

    Chen, Jiehui; Salim, Mariam B.; Matsumoto, Mitsuji

    2010-01-01

    Wireless Sensor Networks (WSNs) designed for mission-critical applications suffer from limited sensing capacities, particularly fast energy depletion. Regarding this, mobile sinks can be used to balance the energy consumption in WSNs, but the frequent location updates of the mobile sinks can lead to data collisions and rapid energy consumption for some specific sensors. This paper explores an optimal barrier coverage based sensor deployment for event driven WSNs where a dual-sink model was designed to evaluate the energy performance of not only static sensors, but Static Sink (SS) and Mobile Sinks (MSs) simultaneously, based on parameters such as sensor transmission range r and the velocity of the mobile sink v, etc. Moreover, a MS mobility model was developed to enable SS and MSs to effectively collaborate, while achieving spatiotemporal energy performance efficiency by using the knowledge of the cumulative density function (cdf), Poisson process and M/G/1 queue. The simulation results verified that the improved energy performance of the whole network was demonstrated clearly and our eDSA algorithm is more efficient than the static-sink model, reducing energy consumption approximately in half. Moreover, we demonstrate that our results are robust to realistic sensing models and also validate the correctness of our results through extensive simulations. PMID:22163503

  15. Soil sampling device with latch assembly having a variable circumferential shape

    DOEpatents

    Meyer, R.D.

    1996-12-24

    The invention relates to an improved sampler which can be operated in any orientation. The design features a positive gripping of the operating rod in a manner to reduce point loads so as to reduce any possibility of jamming of the rod on a retraction stroke until such time as it is positively retained in the fully withdrawn position. In the preferred embodiment, a pair of mating cylindrical latch pieces, held together by a circumferential spring, are used for positive actuation. The inner rod has an angular cut-out which provides the base for the latch when aligned with the latch. A release fixture can be used to free the latch from the cone rod after actuation. The latches are formed in such a manner as they may support themselves within the housing of the sampler until they engage the operating rod. 11 figs.

  16. Evolution of the IBDM Structural Latch Development into a Generic Simplified Design

    NASA Technical Reports Server (NTRS)

    DeVriendt, K.; Dittmer, H.; Vrancken, D.; Urmston, P.; Gracia, O.

    2010-01-01

    This paper presents the evolution in the development of the structural latch for the International Berthing Docking Mechanism (IBDM, see Figure 1). It reports on the lessons learned since completion of the test program on the engineering development unit of the first generation latching system in 2007. The initial latch design has been through a second generation concept in 2008, and now evolved into a third generation of this mechanism. Functional and structural testing on the latest latch hardware has recently been completed with good results. The IBDM latching system will provide the structural connection between two mated space vehicles after berthing or docking. The mechanism guarantees that the interface seals become compressed to form a leak-tight pressure system that creates a passageway for the astronauts.

  17. Soil sampling device with latch assembly having a variable circumferential shape

    DOEpatents

    Meyer, Robert D.

    1996-01-01

    The invention relates to an improved sampler which can be operated in any orientation. The design features a positive gripping of the operating rod in a manner to reduce point loads so as to reduce any possibility of jamming of the rod on a retraction stroke until such time as it is positively retained in the fully withdrawn position. In the preferred embodiment, a pair of mating cylindrical latch pieces, held together by a circumferential spring, are used for positive actuation. The inner rod has an angular cut-out which provides the base for the latch when aligned with the latch. A release fixture can be used to free the latch from the cone rod after actuation. The latches are formed in such a manner as they may support themselves within the housing of the sampler until they engage the operating rod.

  18. Subsonic Maneuvering Effectiveness of High Performance Aircraft Which Employ Quasi-Static Shape Change Devices

    NASA Technical Reports Server (NTRS)

    Montgomery, Raymond C.; Scott, Michael A.; Weston, Robert P.

    1998-01-01

    This paper represents an initial study on the use of quasi-static shape change devices in aircraft maneuvering. The macroscopic effects and requirements for these devices in flight control are the focus of this study. Groups of devices are postulated to replace the conventional leading-edge flap (LEF) and the all-moving wing tip (AMT) on the tailless LMTAS-ICE (Lockheed Martin Tactical Aircraft Systems - Innovative Control Effectors) configuration. The maximum quasi-static shape changes are 13.8% and 7.7% of the wing section thickness for the LEF and AMT replacement devices, respectively. A Computational Fluid Dynamics (CFD) panel code is used to determine the control effectiveness of groups of these devices. A preliminary design of a wings-leveler autopilot is presented. Initial evaluation at 0.6 Mach at 15,000 ft. altitude is made through batch simulation. Results show small disturbance stability is achieved, however, an increase in maximum distortion is needed to statically offset five degrees of sideslip. This only applies to the specific device groups studied, encouraging future research on optimal device placement.

  19. The influence of passivation and electropolishing on the performance of medical grade stainless steels in static and fatigue loading.

    PubMed

    Weldon, L M; McHugh, P E; Carroll, W; Costello, E; O'Bradaigh, C

    2005-02-01

    The effects of surface passivation and electropolishing on the mechanical performance of a group of biomedical grade stainless steels have been investigated. Surface roughness measurements showed that the treatments had a significant effect on the final surface finish. However, static mechanical testing demonstrated no difference in static mechanical properties, regardless of surface treatment. High cycle fatigue testing was carried out at a frequency of 120 Hz with a load ratio of R=0.1, in both air and a simulated in vivo wet corrosive environment. 316LVM (cold worked) proved superior to 316L (annealed) in fatigue performance, in both dry and wet environments. The fatigue performance of both materials did depend on the surface treatment, with electropolishing resulting in better performance than passivation. The fatigue performance of both materials was significantly better in the dry environment in comparison to the wet environment. The dry-to-wet deterioration in fatigue performance was somewhat dependent on the surface treatment for the 316L material but almost independent of surface treatment for the 316LVM material. Significant surface pitting and damage was evident for 316L during fatigue in the wet environment, whereas almost no pitting and damage was observed for 316LVM. PMID:15744598

  20. Static internal performance of a two-dimensional convergent nozzle with thrust-vectoring capability up to 60 deg

    NASA Technical Reports Server (NTRS)

    Leavitt, L. D.

    1985-01-01

    An investigation was conducted at wind-off conditions in the static-test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance characteristics of a two-dimensional convergent nozzle with a thrust-vectoring capability up to 60 deg. Vectoring was accomplished by a downward rotation of a hinged upper convergent flap and a corresponding rotation of a center-pivoted lower convergent flap. The effects of geometric thrust-vector angle and upper-rotating-flap geometry on internal nozzle performance characteristics were investigated. Nozzle pressure ratio was varied from 1.0 (jet off) to approximately 5.0.

  1. Acute Effects of Static Stretching, Dynamic Exercises, and High Volume Upper Extremity Plyometric Activity on Tennis Serve Performance

    PubMed Central

    Gelen, Ertugrul; Dede, Muhittin; Bingul, Bergun Meric; Bulgan, Cigdem; Aydin, Mensure

    2012-01-01

    The purpose of this study was to compare the acute effects of static stretching; dynamic exercises and high volume upper extremity plyometric activity on tennis serve performance. Twenty-six elite young tennis players (15.1 ± 4.2 years, 167.9 ± 5.8 cm and 61.6 ± 8.1 kg) performed 4 different warm-up (WU) routines in a random order on non-consecutive days. The WU methods consisted of traditional WU (jogging, rally and serve practice) (TRAD); traditional WU and static stretching (TRSS); traditional WU and dynamic exercise (TRDE); and traditional WU and high volume upper extremity plyometric activity (TRPLYP). Following each WU session, subjects were tested on a tennis serve ball speed test. TRAD, TRSS, TRDE and TRPLYO were compared by repeated measurement analyses of variance and post-hoc comparisons. In this study a 1 to 3 percent increase in tennis serve ball speed was recorded in TRDE and TRPLYO when compared to TRAD (p< 0.05). However, no significant change in ball speed performance between TRSS and TRAD. (p> 0.05). ICCs for ball speed showed strong reliability (0.82 to 0.93) for the ball speed measurements.The results of this study indicate that dynamic and high volume upper extremity plyometric WU activities are likely beneficial to serve speed of elite junior tennis players. Key points After the traditional warm up in tennis, static stretching has no effect on serve speed. Tennis players should perform dynamic exercises and/or high volume upper extremity plyometric activities to improve their athletic performance. PMID:24150068

  2. Component-cost and performance based comparison of flow and static batteries

    NASA Astrophysics Data System (ADS)

    Hopkins, Brandon J.; Smith, Kyle C.; Slocum, Alexander H.; Chiang, Yet-Ming

    2015-10-01

    Flow batteries are a promising grid-storage technology that is scalable, inherently flexible in power/energy ratio, and potentially low cost in comparison to conventional or "static" battery architectures. Recent advances in flow chemistries are enabling significantly higher energy density flow electrodes. When the same battery chemistry can arguably be used in either a flow or static electrode design, the relative merits of either design choice become of interest. Here, we analyze the costs of the electrochemically active stack for both architectures under the constraint of constant energy efficiency and charge and discharge rates, using as case studies the aqueous vanadium-redox chemistry, widely used in conventional flow batteries, and aqueous lithium-iron-phosphate (LFP)/lithium-titanium-phosphate (LTP) suspensions, an example of a higher energy density suspension-based electrode. It is found that although flow batteries always have a cost advantage (kWh-1) at the stack level modeled, the advantage is a strong function of flow electrode energy density. For the LFP/LTP case, the cost advantages decreases from ∼50% to ∼10% over experimentally reasonable ranges of suspension loading. Such results are important input for design choices when both battery architectures are viable options.

  3. Static performance of nonaxisymmetric nozzles with yaw thrust-vectoring vanes

    NASA Technical Reports Server (NTRS)

    Mason, Mary L.; Berrier, Bobby L.

    1988-01-01

    A static test was conducted in the static test facility of the Langley 16 ft Transonic Tunnel to evaluate the effects of post exit vane vectoring on nonaxisymmetric nozzles. Three baseline nozzles were tested: an unvectored two dimensional convergent nozzle, an unvectored two dimensional convergent-divergent nozzle, and a pitch vectored two dimensional convergent-divergent nozzle. Each nozzle geometry was tested with 3 exit aspect ratios (exit width divided by exit height) of 1.5, 2.5 and 4.0. Two post exit yaw vanes were externally mounted on the nozzle sidewalls at the nozzle exit to generate yaw thrust vectoring. Vane deflection angle (0, -20 and -30 deg), vane planform and vane curvature were varied during the test. Results indicate that the post exit vane concept produced resultant yaw vector angles which were always smaller than the geometric yaw vector angle. Losses in resultant thrust ratio increased with the magnitude of resultant yaw vector angle. The widest post exit vane produced the largest degree of flow turning, but vane curvature had little effect on thrust vectoring. Pitch vectoring was independent of yaw vectoring, indicating that multiaxis thrust vectoring is feasible for the nozzle concepts tested.

  4. Driving and latching of the Starlab pointing mirror doors

    NASA Technical Reports Server (NTRS)

    Beaven, Herbert R., Jr.; Avina, Raymond R.

    1990-01-01

    The Starlab Experiment, a major SDIO technology initiative, is an attached payload which will be delivered into Earth orbit aboard NASA's Space Shuttle in 1991. Starlab will generate and aim an 80 cm diameter laser beam into space through a large opening in the structure which houses the pointing mirror. Two doors, each somewhat larger than a desktop, cover the opening when the laser optics system is nonoperational. Latch Mechanism Assemblies hold the doors shut during liftoff and ascent and, again, during Orbiter reentry. Each door is powered by a Door Drive System during the many open/close cycles between various experiments. The design, testing, and resultant failure modes of these mechanisms are examined.

  5. Laboratory and field performance of FOS sensors in static and dynamic strain monitoring in concrete bridge decks

    NASA Astrophysics Data System (ADS)

    Benmokrane, B.; Debaiky, A.; El-Ragaby, A.; Roy, R.; El-Gamal, S.; El-Salakawy, E.

    2006-03-01

    There is a growing need for designing and constructing innovative concrete bridges using FRP reinforcing bars as internal reinforcement to avoid the corrosion problems and high costs of maintenance and repair. For efficient use and to increase the lifetime of these bridges, it is important to develop efficient monitoring systems for such innovative structures. Fabry-Perot and Bragg fibre optic sensors (FOS) that can measure the strains and temperature are promising candidates for life-long health monitoring of these structures. This article reports laboratory and field performance of Fabry-Perot and Bragg FOS sensors as well as electrical strain gauges in static and dynamic strain monitoring in concrete bridge decks. The laboratory tests include tensile testing of glass FRP bars and testing of full-scale concrete bridge deck slabs reinforced with glass and carbon FRP bars under static and cyclic concentrated loads. The field tests include static and dynamic testing of two bridges reinforced with steel and glass FRP bars. The obtained strain results showed satisfactory agreement between the different gauges.

  6. A performance comparison of static VAr compensator based on Goertzel and FFT algorithm and experimental validation.

    PubMed

    Kececioglu, O Fatih; Gani, Ahmet; Sekkeli, Mustafa

    2016-01-01

    The main objective of the present paper is to introduce a new approach for measuring and calculation of fundamental power components in the case of various distorted waveforms including those containing harmonics. The parameters of active, reactive, apparent power and power factor, are measured and calculated by using Goertzel algorithm instead of fast Fourier transformation which is commonly used. The main advantage of utilizing Goertzel algorithm is to minimize computational load and trigonometric equations. The parameters measured in the new technique are applied to a fixed capacitor-thyristor controlled reactor based static VAr compensation system to achieve accurate power factor correction for the first time. This study is implemented both simulation and experimentally. PMID:27047717

  7. Numerical analysis of static performance comparison of friction stir welded versus riveted 2024-T3 aluminum alloy stiffened panels

    NASA Astrophysics Data System (ADS)

    Shao, Qing; He, Yuting; Zhang, Teng; Wu, Liming

    2014-07-01

    Most researches on the static performance of stiffened panel joined by friction stir welding(FSW) mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method(FEM) is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted

  8. Static internal performance of a nonaxisymmetric vaned thrust reverser with flow splay capability

    NASA Technical Reports Server (NTRS)

    Bangert, Linda S.; Leavitt, Laurence D.

    1989-01-01

    An investigation was conducted in the Static Test Facility of the Langley 16-Foot Transonic Tunnel on a dual-port, nonaxisymmetric, block-and-turn type thrust reverser model with vane cascades in the reverser ports which turned the flow in the splay direction and aided in turning the flow in the reverse direction. Splaying reverser flow is a method of delaying to lower landing ground roll speeds the reingestion of hot exhaust flow into the inlets. Exhaust flow splay can also help prevent the impingement of hot exhaust gases on the empennage surfaces when the reverser is integrated into an actual airframe. The vane cascades consisted of two sets of perpendicular vanes with a variable number of turning and splay vanes. A skewed vane box was also tested which had only one set of vanes angled to provide both turning and splay. Vane cascades were designed to provide different amounts of flow splay in the top and bottom ports. Inner doors, trim tabs, and an orifice plate all provided means of varying the port area for reverser flow modulation. The outer door position was varied as a means of influencing the flow reverse angle. Nozzle pressure ratio was varied from 1.75 to approximately 6.00.

  9. Directed self-assembly of microcomponents enabled by laser-activated bubble latching.

    PubMed

    Jiang, Li; Erickson, David

    2011-09-01

    This article introduces a method for microscale assembly using laser-activated bubble latching. The technique combines the advantages of directed fluidic assembly and surface tension-driven latching to create arbitrarily complex and irregular structures with unique properties. The bubble latches, generated through the laser degradation of the tile material, are created on the fly, reversibly linking components at user-determined locations. Different phases of latching bubble growth are analyzed, and shear force calculations show that each bubble is able to support a tensile force of approximately 0.33 μN. We demonstrate that by exploiting the compressibility of bubbles, assembled objects can be made to switch between rigid and flexible states, facilitating component assembly and transport. Furthermore, we show reconfiguration capabilities through the use of bubble hinging. This novel hybrid approach to the assembly of microscale components offers significant user control while retaining a simplistic design environment. PMID:21793555

  10. Latching mechanism for deployable/re-stowable columns useful in satellite construction

    NASA Technical Reports Server (NTRS)

    Ahl, E. L., Jr. (Inventor)

    1986-01-01

    A column longeron latch assembly provides the securing mechanism for the deployable, telescoping column of a hoop/column antenna. The column is an open lattice structure with three longerons disposed 120 deg apart as the principle load bearing member. The column is deployed from a pair of eleven nested bays disposed on opposite sides of a center section under the influence of a motor-cable-pulley system. The longeron latch is a four bar linkage mechanism using the over-center principle for automatically locking the longeron sections into position during deployment. The latch is unlocked when the antenna is to be restowed. A spring pack disposed in the end of each longeron serves to absorb stress forces on the deployed column through the cam head piston and abutting latch from an adjacent longeron.

  11. Design and analysis of a keel latch for use on the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Calvert, John; Stinson, Melanie

    1986-01-01

    The mechanical design of the keel latch is discussed, as well as the stress analysis of the keel latch. Background information; mechanical design requirements; some of the initial design considerations; the design considerations that led to the selection of the final design; the mechanics of the final design; testing that has been and will be accomplished to verify that design requirements have been met; and future tests are discussed.

  12. Characterization of Single Event Latch-Up Cross Section in Prototype ALPIDE Sensor

    NASA Astrophysics Data System (ADS)

    Torales-Acosta, Fernando

    2015-10-01

    Particles containing heavy quarks are excellent probes into the full evolution of QGP, and the Inner Tracking System (ITS) of ALICE is responsible for detecting these short-lived heavy particles by measuring their impact parameter, the point at which they decay relative to the initial collision. ALPIDE is a next generation monolithic active pixel sensor (MAPS) designed for the ALICE ITS upgrade in 2018 that would increase the impact parameter resolution and readout speed of the ITS. Like most silicon using CMOS technology, however, ALPIDE can suffer from single event latch-up. The aim of this experiment was to measure the cross section of latch-up in a prototype ALPIDE sensor using the 88'' cyclotron facility at Lawrence Berkeley National Laboratory. High statistics in a range of ions with low linear energy transfers (LETs) were needed to characterize the onset curve of latch-up in the sensor. It was found that latch-up occurred with reasonable statistics at LETs as low as 5 MeV/(mg/cm2). The sensor, however, undergoes a power cycle after each latch-up. As a result, significant dead time correction was required for accurate calculation of the sensor's cross section. Potential damage to the sensor from a particularly strong latch-up was also observed.

  13. Predicting Material Performance in the Space Environment from Laboratory Test Data, Static Design Environments, and Space Weather Models

    NASA Technical Reports Server (NTRS)

    Minow, Josep I.; Edwards, David L.

    2008-01-01

    Qualifying materials for use in the space environment is typically accomplished with laboratory exposures to simulated UV/EUV, atomic oxygen, and charged particle radiation environments with in-situ or subsequent measurements of material properties of interest to the particular application. Choice of environment exposure levels are derived from static design environments intended to represent either mean or extreme conditions that are anticipated to be encountered during a mission. The real space environment however is quite variable. Predictions of the on orbit performance of a material qualified to laboratory environments can be done using information on 'space weather' variations in the real environment. This presentation will first review the variability of space environments of concern for material degradation and then demonstrate techniques for using test data to predict material performance in a variety of space environments from low Earth orbit to interplanetary space using historical measurements and space weather models.

  14. A note on the performance analysis of static locking in distributed database systems

    NASA Technical Reports Server (NTRS)

    Kuang, Yinghong; Mukkamala, Ravi

    1991-01-01

    Even though transaction deadlocks can severely affect the performance of distributed database systems, many current evaluation techniques ignore this aspect. Shyu and Li proposed an evaluation method which takes deadlocks into consideration. However, their technique is limited to exclusive locking. Using this technique, researchers illustrate the impact of deadlocks in the presence of shared locking on distributed database performance.

  15. Static internal performance of a thrust vectoring and reversing two-dimensional convergent-divergent nozzle with an aft flap

    NASA Technical Reports Server (NTRS)

    Re, R. J.; Leavitt, L. D.

    1986-01-01

    The static internal performance of a multifunction nozzle having some of the geometric characteristics of both two-dimensional convergent-divergent and single expansion ramp nozzles has been investigated in the static-test facility of the Langley 16-Foot Transonic Tunnel. The internal expansion portion of the nozzle consisted of two symmetrical flat surfaces of equal length, and the external expansion portion of the nozzle consisted of a single aft flap. The aft flap could be varied in angle independently of the upper internal expansion surface to which it was attached. The effects of internal expansion ratio, nozzle thrust-vector angle (-30 deg. to 30 deg., aft flap shape, aft flap angle, and sidewall containment were determined for dry and afterburning power settings. In addition, a partial afterburning power setting nozzle, a fully deployed thrust reverser, and four vertical takeoff or landing nozzle, configurations were investigated. Nozzle pressure ratio was varied up to 10 for the dry power nozzles and 7 for the afterburning power nozzles.

  16. Investigation into the long-term effects of static and PNF stretching exercises on range of motion and jump performance.

    PubMed

    Yuktasir, Bekir; Kaya, Fatih

    2009-01-01

    The purpose of the present study was to investigate the long-term effects of two different stretching techniques on the range of motion (ROM) and on drop jump (DJ). DJ scores were assessed by means of a contact mat connected to a digital timer. ROM was measured by use of a goniometer. The training was carried out four times a week for 6 weeks on 10 subjects as passive static stretching (SS), and on 9 subjects as contract-relax PNF (CRPNF) stretching. The remaining nine subjects did not perform any exercises (control group). One-way Analysis of Variance (ANOVA) results indicated that the differences among groups on DJ were not statistically different (F(2,27)=.41, p>.05). ROM values were significantly higher for both stretching groups, while no change was observed for the control group. In conclusion, static and proprioceptive neuromuscular facilitation (PNF) stretching techniques improved the ROM, but neither of the stretching exercises had any statistically significant effect on the DJ scores. PMID:19118789

  17. Robust mitotic entry is ensured by a latching switch

    PubMed Central

    Tuck, Chloe; Zhang, Tongli; Potapova, Tamara; Malumbres, Marcos; Novák, Béla

    2013-01-01

    Summary Cell cycle events are driven by Cyclin dependent kinases (CDKs) and by their counter-acting phosphatases. Activation of the Cdk1:Cyclin B complex during mitotic entry is controlled by the Wee1/Myt1 inhibitory kinases and by Cdc25 activatory phosphatase, which are themselves regulated by Cdk1:Cyclin B within two positive circuits. Impairing these two feedbacks with chemical inhibitors induces a transient entry into M phase referred to as mitotic collapse. The pathology of mitotic collapse reveals that the positive circuits play a significant role in maintaining the M phase state. To better understand the function of these feedback loops during G2/M transition, we propose a simple model for mitotic entry in mammalian cells including spatial control over Greatwall kinase phosphorylation. After parameter calibration, the model is able to recapture the complex and non-intuitive molecular dynamics reported by Potapova et al. (Potapova et al., 2011). Moreover, it predicts the temporal patterns of other mitotic regulators which have not yet been experimentally tested and suggests a general design principle of cell cycle control: latching switches buffer the cellular stresses which accompany cell cycle processes to ensure that the transitions are smooth and robust. PMID:24143279

  18. Effect of several geometric parameters on the static internal performance of three nonaxisymmetric nozzle concepts

    NASA Technical Reports Server (NTRS)

    Berrier, B. L.; Re, R. J.

    1979-01-01

    Effects of several geometric parameters on the internal performance of nonaxisymmetric convergent-divergent, single-ramp expansion, and wedge nozzles were investigated at nozzle pressure ratios up to approximately 10. In addition, two different thrust-vectoring schemes were investigated with the wedge nozzle. The results indicated that as with conventional round nozzles, peak nonaxisymmetric nozzle, internal performance occurred near the nozzle pressure ratio required for fully expanded exhaust flow. Nozzle sidewall length or area generally had little effect on the internal performance of the nozzles investigated.

  19. Evaluation of the performance of two state-transfer Hamiltonians in the presence of static disorder

    NASA Astrophysics Data System (ADS)

    Pavlis, A. K.; Nikolopoulos, G. M.; Lambropoulos, P.

    2016-03-01

    We analyze the performance of two quantum-state-transfer Hamiltonians in the presence of diagonal and off-diagonal disorders, and in terms of different measures. The first Hamiltonian pertains to a fully engineered chain, and the second to a chain with modified boundary couplings. The task is to find which Hamiltonian is the most robust to given levels of disorder and irrespective of the input state. In this respect, it is shown that the performances of the two protocols are approximately equivalent.

  20. Evaluation of the performance of two state-transfer Hamiltonians in the presence of static disorder

    NASA Astrophysics Data System (ADS)

    Pavlis, A. K.; Nikolopoulos, G. M.; Lambropoulos, P.

    2016-06-01

    We analyze the performance of two quantum-state-transfer Hamiltonians in the presence of diagonal and off-diagonal disorders, and in terms of different measures. The first Hamiltonian pertains to a fully engineered chain, and the second to a chain with modified boundary couplings. The task is to find which Hamiltonian is the most robust to given levels of disorder and irrespective of the input state. In this respect, it is shown that the performances of the two protocols are approximately equivalent.

  1. Effects of acute static stretching of the throwing shoulder on pitching performance of national collegiate athletic association division III baseball players.

    PubMed

    Haag, Samuel J; Wright, Glenn A; Gillette, Cordial M; Greany, John F

    2010-02-01

    Stretching is a common component of an athletic warm-up even though many studies have demonstrated that pre-event static stretching can decrease strength and power performance. The purpose of this study was to examine the effects of acute static stretching of the throwing shoulder on pitching velocity and accuracy of National Collegiate Athletic Association Division III baseball players. Twelve collegiate baseball players, including 6 pitchers and 6 position players, participated in the study. Each participant completed 2 separate testing protocols over a span of 4-6 days. In the experimental condition (SS), 6 static stretches were applied to the throwing shoulder after an active warm-up. After a rest period of 5-10 minutes, participants were allowed 5 warm-up pitches from a pitching mound. Participants then threw 10 pitches measured for velocity and accuracy. The control condition (NS) followed the same procedure but did not include the 6 static stretches. Testing was conducted in an indoor practice facility during normal team practice. No significant differences were found in average velocity, maximum velocity, or accuracy measures when comparing the SS and NS conditions. These results suggest that acute static stretching of the throwing shoulder does not have a significant impact on baseball pitching performance. Static stretching of the shoulder may be performed during a warm-up before a throwing activity. PMID:20072054

  2. Static internal performance of single expansion-ramp nozzles with thrust vectoring and reversing

    NASA Technical Reports Server (NTRS)

    Re, R. J.; Berrier, B. L.

    1982-01-01

    The effects of geometric design parameters on the internal performance of nonaxisymmetric single expansion-ramp nozzles were investigated at nozzle pressure ratios up to approximately 10. Forward-flight (cruise), vectored-thrust, and reversed-thrust nozzle operating modes were investigated.

  3. Design and analysis of a novel latch system implementing fiber-reinforced composite materials

    NASA Astrophysics Data System (ADS)

    Guevara Arreola, Francisco Javier

    The use of fiber-reinforced composite materials have increased in the last four decades in high technology applications due to their exceptional mechanical properties and low weight. In the automotive industry carbon fiber have become popular exclusively in luxury cars because of its high cost. However, Carbon-glass hybrid composites offer an effective alternative to designers to implement fiber-reinforced composites into several conventional applications without a considerable price increase maintaining most of their mechanical properties. A door latch system is a complex mechanism that is under high loading conditions during car accidents such as side impacts and rollovers. Therefore, the Department of Transportation in The United States developed a series of tests that every door latch system comply in order to be installed in a vehicle. The implementation of fiber-reinforced composite materials in a door latch system was studied by analyzing the material behavior during the FMVSS No. 206 transverse test using computational efforts and experimental testing. Firstly, a computational model of the current forkbolt and detent structure was developed. Several efforts were conducted in order to create an effective and time efficient model. Two simplified models were implemented with two different contact interaction approaches. 9 composite materials were studied in forkbolt and 5 in detent including woven carbon fiber, unidirectional carbon fiber, woven carbon-glass fiber hybrid composites and unidirectional carbon-glass fiber hybrid composites. The computational model results showed that woven fiber-reinforced composite materials were stiffer than the unidirectional fiber-reinforced composite materials. For instance, a forkbolt made of woven carbon fibers was 20% stiffer than a forkbolt made of unidirectional fibers symmetrically stacked in 0° and 90° alternating directions. Furthermore, Hybrid composite materials behaved as expected in forkbolt noticing a decline

  4. Effect of varying internal geometry on the static performance of rectangular thrust-reverser ports

    NASA Technical Reports Server (NTRS)

    Re, Richard J.; Mason, Mary L.

    1987-01-01

    An investigation has been conducted to evaluate the effects of several geometric parameters on the internal performance of rectangular thrust-reverser ports for nonaxisymmetric nozzles. Internal geometry was varied with a test apparatus which simulated a forward-flight nozzle with a single, fully deployed reverser port. The test apparatus was designed to simulate thrust reversal (conceptually) either in the convergent section of the nozzle or in the constant-area duct just upstream of the nozzle. The main geometric parameters investigated were port angle, port corner radius, port location, and internal flow blocker angle. For all reverser port geometries, the port opening had an aspect ratio (throat width to throat height) of 6.1 and had a constant passage area from the geometric port throat to the exit. Reverser-port internal performance and thrust-vector angles computed from force-balance measurements are presented.

  5. Novel electro-thermal latching micro-switch based on Ni/electrophoretic polymer micro-cantilevers

    NASA Astrophysics Data System (ADS)

    Cheng, Ping; Zhang, Ying; Mao, Shenping; Wang, Hong; Ding, Guifu; Zhang, Congchun; Dai, Xuhan; Zhao, Xiaolin

    2014-12-01

    A novel electro-thermal and mechanical latching micro-switch is proposed in this study. Theoretical calculations were carried out to determine the geometric parameters of the micro-switch. An electrophoretic polymer film was introduced as the actuation layer to sustain the nickel resistance heater of the electro-thermal actuator. Compared to SU-8, the electrophoretic polymer film had a large thermal expansion coefficient as well as a high adhesive force between the polymer film and Ni. By optimizing the processes, the micro-switch was finally fabricated using a MEMS process. In order to demonstrate the dynamic performance of the micro-switch, a sequential double-pulsed power was used to actuate the fabricated micro-switch, which was connected with an external circuit. The testing results indicated that the electro-thermal latching micro-switch could control the ON/OFF state of the external circuit.This demonstrated the bistable behaviour of the electro-thermal micro-switch.

  6. Linear Static Structural and Vibration Analysis on High-Performance Computers

    NASA Technical Reports Server (NTRS)

    Baddourah, Majdi; Storaasli, Olaf O.; Bostic, Susan

    1993-01-01

    Parallel computers offer the opportunity to significantly reduce the computation time necessary to analyze large-scale aerospace structures. This paper presents algorithms developed for and implemented on a massively-parallel computers hereafter referred to as Scalable High Performance Computers (SHPC) for the most computationally intensive tasks involved in structural analysis, namely, generation and assembly of system matrices, solution of systems of equations and calculation of the eigenvalues and eigenvectors. Results on SHPC are presented for large-scale structural problems (i.e. Models of high speed civil transport). The goal of this research is to develop new efficient technique which extend structural analysis to SHPC and make large-scale structural analyses tractable.

  7. Greater volumes of static and dynamic stretching within a warm-up do not impair star excursion balance performance.

    PubMed

    Belkhiria-Turki, L; Chaouachi, A; Turki, O; Hammami, R; Chtara, M; Amri, M; Drinkwater, E J; Behm, D G

    2014-06-01

    Based on the conflicting static stretching (SS) literature and lack of dynamic stretching (DS) literature regarding the effects of differing volumes of stretching on balance, the present study investigated the effects of 4, 8, and 12 sets of SS and DS following a 5 min aerobic running warm-up on the star excursion balance test (SEBT). The objective was to examine an optimal stretch modality and volume to enhance dynamic balance. A randomized, within-subjects experimental design with repeated measures for stretching (SS and DS) versus no-stretching treatment was used to examine the acute effects of 10 (4 sets), 20 (8 sets), and 30 (12 sets) min, of 15s repetitions per muscle of SS and/or DS following a 5 min aerobic warm-up on the performance of the SEBT. Results indicated that a warm-up employing either SS or DS of any volume generally improves SEBT by a "small" amount with effect sizes ranging from 0.06 to 0.50 (11 of 18 conditions>75% likely to exceed the 1.3-1.9% smallest worthwhile change). Secondly, the difference between static and dynamic warm-up on this observed improvement with warm-up improvement was "trivial" to "moderate" (d=0.04 to 0.57) and generally "unclear" (only two of nine conditions>75% likely to exceed the smallest worthwhile change). Finally, the effect of increasing the volume of warm-up on the observed improvement with a warm-up is "trivial" to "small" (d<0.40) and generally "unclear" (only three of 12 conditions>75% likely to exceed the smallest worthwhile change). In summary, an aerobic running warm-up with stretching that increases core and muscle temperature whether it involves SS or DS may be expected to provide small improvements in the SEBT. PMID:24739290

  8. Static Performance of a Fixed-Geometry Exhaust Nozzle Incorporating Porous Cavities for Shock-Boundary Layer Interaction Control

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Hunter, Craig A.

    1999-01-01

    An investigation was conducted in the model preparation area of the Langley 16-Foot Transonic Tunnel to determine the internal performance of a fixed-geometry exhaust nozzle incorporating porous cavities for shock-boundary layer interaction control. Testing was conducted at static conditions using a sub-scale nozzle model with one baseline and 27 porous configurations. For the porous configurations, the effects of percent open porosity, hole diameter, and cavity depth were determined. All tests were conducted with no external flow at nozzle pressure ratios from 1.25 to approximately 9.50. Results indicate that baseline nozzle performance was dominated by unstable, shock-induced, boundary-layer separation at over-expanded conditions. Porous configurations were capable of controlling off-design separation in the nozzle by either alleviating separation or encouraging stable separation of the exhaust flow. The ability of the porous nozzle concept to alternately alleviate separation or encourage stable separation of exhaust flow through shock-boundary layer interaction control offers tremendous off-design performance benefits for fixed-geometry nozzle installations. In addition, the ability to encourage separation on one divergent flap while alleviating it on the other makes it possible to generate thrust vectoring using a fixed-geometry nozzle.

  9. Performance of an anaerobic, static bed, fixed film bioreactor for chlorinated solvent treatment

    USGS Publications Warehouse

    Lorah, Michelle M.; Walker, Charles; Graves, Duane

    2015-01-01

    Anaerobic, fixed film, bioreactors bioaugmented with a dechlorinating microbial consortium were evaluated as a potential technology for cost effective, sustainable, and reliable treatment of mixed chlorinated ethanes and ethenes in groundwater from a large groundwater recovery system. Bench- and pilot-scale testing at about 3 and 13,500 L, respectively, demonstrated that total chlorinated solvent removal to less than the permitted discharge limit of 100 μg/L. Various planned and unexpected upsets, interruptions, and changes demonstrated the robustness and reliability of the bioreactor system, which handled the operational variations with no observable change in performance. Key operating parameters included an adequately long hydraulic retention time for the surface area, a constant supply of electron donor, pH control with a buffer to minimize pH variance, an oxidation reduction potential of approximately −200 millivolts or lower, and a well-adapted biomass capable of degrading the full suite of chlorinated solvents in the groundwater. Results indicated that the current discharge criteria can be met using a bioreactor technology that is less complex and has less downtime than the sorption based technology currently being used to treat the groundwater.

  10. Relative performance of antisymmetric angle-ply laminated stiffened hypar shell roofs with cutout in terms of static behavior

    NASA Astrophysics Data System (ADS)

    Chowdhury, Puja B.; Mitra, Anirban; Sahoo, Sarmila

    2016-01-01

    A review of literature reveals that bending analysis of laminated composite stiffened hypar shells with cutout have not received due attention. Being a doubly ruled surface, a skewed hypar shell fulfils aesthetic as well as ease of casting requirements. Further, this shell allows entry of north light making it suitable as civil engineering roofing units. Hypar shell with cutout subjected to uniformly distributed load exhibits improved performances with stiffeners. Hence relative performances of antisymmetric angle-ply laminated composite stiffened hypar shells in terms of displacements and stress resultants are studied in this paper under static loading. A curved quadratic isoparametric eight noded element and three noded beam elements are used to model the shell surface and the stiffeners respectively. Results obtained from the present study are compared with established ones to check the correctness of the present approach. A number of additional problems of antisymmetric angle-ply laminated composite stiffened hypar shells are solved for various fibre orientations, number of layers and boundary conditions. Results are interpreted from practical application standpoints and findings important for a designer to decide on the shell combination among a number of possible options are highlighted.

  11. Design and Development of a Miniaturized Double Latching Solenoid Valve for the Sample Analysis at Mars Instrument Suite

    NASA Technical Reports Server (NTRS)

    Smith, James T.

    2008-01-01

    The development of the in-house Miniaturized Double Latching Solenoid Valve, or Microvalve, for the Gas Processing System (GPS) of the Sample Analysis at Mars (SAM) instrument suite is described. The Microvalve is a double latching solenoid valve that actuates a pintle shaft axially to hermetically seal an orifice. The key requirements and the design innovations implemented to meet them are described.

  12. The effects of static stretching on running economy and endurance performance in female distance runners during treadmill running.

    PubMed

    Mojock, Chris D; Kim, Jeong-Su; Eccles, David W; Panton, Lynn B

    2011-08-01

    Stretching can lead to decreased muscle stiffness and has been associated with decreased force and power production. The purpose of this study was to investigate the acute effects of static stretching (SS) on running economy and endurance performance in trained female distance runners. Twelve long distance female (30 ± 9 years) runners were assessed for height (159.4 ± 7.4 cm), weight (54.8 ± 7.2 kg), % body fat (19.7 ± 2.8%), and maximal oxygen consumption (VO2max: 48.4 ± 5.1 ml·kg(-1)·min(-1)). Participants performed 2 sessions of 60-minute treadmill runs following a randomly assigned SS protocol or quiet sitting (QS). During the first 30 minutes (running economy), expired gases, heart rate (HR), and rating of perceived exertion (RPE) were recorded while the participant ran at 65% VO2max. During the final 30 minutes (endurance performance), distance covered, speed, HR, and RPE were recorded while the participant attempted to cover as much distance as possible. Repeated measures analyses of variance were performed on the data. Significance was accepted at p < 0.05. The SS measured by sit-and-reach increased flexibility (SS: 29.8 ± 8.3 vs. QS: 33.1 ± 8.1 cm) but had no effect on running economy (VO2: 33.7 ± 3.2 vs. 33.8 ± 2.3 ml·kg(-1)·min(-1)), calorie expenditure (270 ± 41 vs. 270 ± 41 kcal), HR (157 ± 10 vs. 160 ± 12 b·min(-1)), or endurance performance (5.5 ± 0.6 vs. 5.5 ± 0.7 km). These findings indicated that stretching did not have an adverse effect on endurance performance in trained women. This suggests that the performance decrements previously associated with stretching may not occur in trained women. PMID:21610517

  13. Fabrication and Assembly of High-Precision Hinge and Latch Joints for Deployable Optical Instruments

    NASA Technical Reports Server (NTRS)

    Phelps, James E.

    1999-01-01

    Descriptions are presented of high-precision hinge and latch joints that have been co-developed, for application to deployable optical instruments, by NASA Langley Research Center and Nyma/ADF. Page-sized versions of engineering drawings are included in two appendices to describe all mechanical components of both joints. Procedures for assembling the mechanical components of both joints are also presented. The information herein is intended to facilitate the fabrication and assembly of the high-precision hinge and latch joints, and enable the incorporation of these joints into the design of deployable optical instrument systems.

  14. Design and Analysis of a Keel Latch for Use on the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Calvert, John; Stinson, Melanie

    1986-01-01

    This paper will be divided into two parts. The first part will deal with the mechanical design of the keel latch. The second part will be the stress analysis of the keel latch. The first part will present: (1) background information; (2) mechanical design requirements; (3) some of the initial design considerations; (4) the design considerations that led to the selection of the final design; (5) the mechanics of the final design; (6) testing that has been and will be accomplished to verify that design requirements have been met; and (7) future tests.

  15. Performance of Compressor of XJ-41-V Turbojet Engine. 3; Compressor Static-Pressure Rise at Equivalent Compressor Speeds of 5000, 7000, 8000, and 9000 rpm

    NASA Technical Reports Server (NTRS)

    Creagh, John W. R.; Ginsburg, Ambrose

    1947-01-01

    At the request of the Air Materiel Command, Army Air Forces, an investigation is being conducted at the NACA Cleveland laboratory to determine the performance characteristics of the XJ-41-V turbojet-engine compressor. The static-pressure variation in the direction of flow through the compressor was presented in reference 1 for an equivalent speed of 8000 rpm. An analysis of these pressure indicated that the maximum-flow limitation of the compressor was caused by separation, which reduced the effective flow area at the vaned-collector entrance. As a result of this analysis, the flow area at the vaned-collector entrance was increased to obtain larger mass flows. The area increase was obtained by cutting back the entrance edges of the collector vanes, which resulted in an increased vaneless-diffuser radius. Comparative performance of the original and revised compressors at an equivalent speed of 8000 rpm is presented. The static-pressure rise through the compressor, determined from static pressures at the impeller entrance and the vaned-collector exit, is also presented together with the compressor adiabatic efficiency and the mass flow over an equivalent speed range from 5000 to 9000 rpm. These static-pressure data are presented for the purpose of correlating the compressor performance with the turbojet-engine performance.

  16. Flip-chip fabrication of integrated micromirror arrays using a novel latching off-chip hinge mechanism

    NASA Astrophysics Data System (ADS)

    Michalicek, M. Adrian; Bright, Victor M.

    2001-10-01

    This paper presents the design, fabrication, modeling, and testing of various arrays of cantilever micromirror devices integrated atop CMOS control electronics. The upper layers of the arrays are prefabricated in the MUMPs process and then flip-chip transferred to CMOS receiving modules using a novel latching off-chip hinge mechanism. This mechanism allows the micromirror arrays to be released, rotated off the edge of the host module and then bonded to the receiving module using a standard probe station. The hinge mechanism supports the arrays by tethers that are severed to free the arrays once bonded. The resulting devices are inherently planarized since the bottom of the first releasable MUMPs layer becomes the surface of the integrated mirror. The working devices are formed by mirror surfaces bonded to address electrodes fabricated above static memory cells on the CMOS module. These arrays demonstrate highly desirable features such as compatible address potentials, less than 2 nm of RMS roughness, approximately 1 micrometers of lateral position accuracy and the unique ability to metallize reflective surfaces without masking. Ultimately, the off-chip hinge mechanism enables very low-cost, simple, reliable, repeatable and accurate assembly of advanced MEMS and integrated microsystems without specialized equipment or complex procedures.

  17. Where Do the Children Play? A Manual for Latch Key Child Development Programs.

    ERIC Educational Resources Information Center

    YMCA of Metropolitan Portland, OR.

    This manual outlines the goals, guidelines, and requirements of Y.M.C.A. Latch Key Child Development Programs, which provide before- and after-school day care services for children who otherwise might be at home with no adult supervision. Included is information on how to begin a program, enrollment procedures, facilities, space utilization, daily…

  18. Apollo 14 mission: Failure to achieve docking probe capture latch engagement

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Six docking attempts were required in order to successfully achieve capture latch engagement during the transposition and docking phase following translunar injection. After docking, the probe and drogue were examined by the crew. Probe operation appeared normal and radial marks were noted on the drogue. During all subsequent operations, the probe operated properly.

  19. Heritage Adoption Lessons Learned, Active Mirror Telescope Cover Deployment and Latch Mechanism

    NASA Technical Reports Server (NTRS)

    Wincentsen, James E.

    2006-01-01

    The Active Mirror Telescope (AMT) task adopted the Cover Deployment and Latch Mechanism (CDLM) design as used on the Galaxy Evolution Explorer (GALEX) project. The three separate mechanisms that comprise the CDLM will be discussed in this paper in addition to a focus on heritage adoption lessons learned and specific examples. These lessons learned will be valuable to any project considering the use of heritage designs.

  20. A light writable microfluidic "flash memory": optically addressed actuator array with latched operation for microfluidic applications.

    PubMed

    Hua, Zhishan; Pal, Rohit; Srivannavit, Onnop; Burns, Mark A; Gulari, Erdogan

    2008-03-01

    This paper presents a novel optically addressed microactuator array (microfluidic "flash memory") with latched operation. Analogous to the address-data bus mediated memory address protocol in electronics, the microactuator array consists of individual phase-change based actuators addressed by localized heating through focused light patterns (address bus), which can be provided by a modified projector or high power laser pointer. A common pressure manifold (data bus) for the entire array is used to generate large deflections of the phase change actuators in the molten phase. The use of phase change material as the working media enables latched operation of the actuator array. After the initial light "writing" during which the phase is temporarily changed to molten, the actuated status is self-maintained by the solid phase of the actuator without power and pressure inputs. The microfluidic flash memory can be re-configured by a new light illumination pattern and common pressure signal. The proposed approach can achieve actuation of arbitrary units in a large-scale array without the need for complex external equipment such as solenoid valves and electrical modules, which leads to significantly simplified system implementation and compact system size. The proposed work therefore provides a flexible, energy-efficient, and low cost multiplexing solution for microfluidic applications based on physical displacements. As an example, the use of the latched microactuator array as "normally closed" or "normally open" microvalves is demonstrated. The phase-change wax is fully encapsulated and thus immune from contamination issues in fluidic environments. PMID:18305870

  1. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    SciTech Connect

    Melcher, Karsten; Ng, Ley-Moy; Zhou, X Edward; Soon, Fen-Fen; Xu, Yong; Suino-Powell, Kelly M; Park, Sang-Youl; Weiner, Joshua J; Fujii, Hiroaki; Chinnusamy, Viswanathan; Kovach, Amanda; Li, Jun; Wang, Yonghong; Li, Jiayang; Peterson, Francis C; Jensen, Davin R; Yong, Eu-Leong; Volkman, Brian F; Cutler, Sean R; Zhu, Jian-Kang; Xu, H Eric

    2010-01-12

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved β-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.

  2. Design and characterization of a thermally actuated latching MEMS switch for telecommunication applications

    NASA Astrophysics Data System (ADS)

    Dellaert, D.; Doutreloigne, J.

    2014-07-01

    This paper describes the design and characterization of a thermal actuator and a latching MEMS switch, using the actuator. The proposed MEMS switch is designed for applications in telecommunication, in which it could be an alternative solution for the now existing electromagnetic relays for automated distribution frames. A MEMS-based switching matrix could be a very attractive solution as it can be made very compact, cost-effective, reliable and scalable. The actuators used in the switch use a polysilicon heater, which heats up the structure and causes deflection. The actuators were fabricated by using MetalMUMPs technology and measured results showed good agreement with the finite element results. Using these actuators, latching switches were also successfully fabricated. No energy is needed to stay in the open or closed state of the switch, which saves energy, but also keeps the interconnection state of the switching matrix in case of a power failure. The time- and current-dependent switch resistance was also measured and remained below 1.52 Ω after 105 latching cycles. The proposed switches could be very useful in a switching matrix for an automated distribution frame.

  3. Dissociation of Bak α1 helix from the core and latch domains is required for apoptosis.

    PubMed

    Alsop, Amber E; Fennell, Stephanie C; Bartolo, Ray C; Tan, Iris K L; Dewson, Grant; Kluck, Ruth M

    2015-01-01

    During apoptosis, Bak permeabilizes mitochondria after undergoing major conformational changes, including poorly defined N-terminal changes. Here, we characterize those changes using 11 antibodies that were epitope mapped using peptide arrays and mutagenesis. After Bak activation by Bid, epitopes throughout the α1 helix are exposed indicating complete dissociation of α1 from α2 in the core and from α6-α8 in the latch. Moreover, disulfide tethering of α1 to α2 or α6 blocks cytochrome c release, suggesting that α1 dissociation is required for further conformational changes during apoptosis. Assaying epitope exposure when α1 is tethered shows that Bid triggers α2 movement, followed by α1 dissociation. However, α2 reaches its final position only after α1 dissociates from the latch. Thus, α1 dissociation is a key step in unfolding Bak into three major components, the N terminus, the core (α2-α5) and the latch (α6-α8). PMID:25880232

  4. Performance of pancake coils of parallel co-wound Ag/BSCCO tape conductors in static and ramped magnetic fields

    SciTech Connect

    Schwenterly, S.W.; Lue, J.W.; Lubell, M.S.; Walker, M.S.; Hazelton, D.W.; Haldar, P.; Rice, J.A.; Hoehn, J.G. Jr.; Motowidlo, L.R.

    1994-12-31

    Critical Currents are reported for several Ag/BSCCO single-pancake coils in static magnetic fields ranging from 0 to 5 T and temperatures from 4.2 K to 105 K. The sample coils were co-wound of one to six tape conductors in parallel. Since the closed loops formed in such an arrangement could lead to eddy current heating or instability in changing fields, one of the coils was also tested in helium gas, in fields ramped at rates of up to 1.5 T/s. For these quasi-adiabatic tests, at each temperature the transport current was set just below the critical value for a preset static field of 3.3 or 4.9 T. The field was then rapidly ramped down to zero, held for 20 sec, and then ramped back up to the original value. The maximum observed temperature transient of about 1.7 K occurred at 9 K, for a field change of 4.75 T. The temperature transients became negligible when the sample was immersed in liquid helium. Above 30 K, the transients were below 1 K. These results give confidence that parallel co-wound HTSC coils are stable in a rapidly-ramped magnetic field, without undue eddy current heating.

  5. Static induction transistor using TaN thin film as gate electrode for high-performance application

    NASA Astrophysics Data System (ADS)

    Zheng, Z. W.; Chen, Y. C.

    2014-03-01

    In this study, static induction transistor (SIT) using TaN thin film as gate electrode was fabricated and the characteristics of this device were investigated. The electrical characteristics showed that the drain-source current was controlled by the bias voltage that applied to the TaN gate electrode. The typical SIT operations with non-saturation property and a transition from linear to nonlinear behavior were observed in the drainsource I-V characteristics. Furthermore, compared with the traditional devices, this SIT device can obtain a high working current (˜5 mA) at a low driving voltage (˜3 V) with a small threshold voltage (˜1 V), showing its high potential for high current and low voltage application.

  6. Static test-stand performance of the YF-102 turbofan engine with several exhaust configurations for the Quiet Short-Haul Research Aircraft (QSRA)

    NASA Technical Reports Server (NTRS)

    Mcardle, J. G.; Homyak, L.; Moore, A. S.

    1979-01-01

    The performance of a YF-102 turbofan engine was measured in an outdoor test stand with a bellmouth inlet and seven exhaust-system configurations. The configurations consisted of three separate-flow systems of various fan and core nozzle sizes and four confluent-flow systems of various nozzle sizes and shapes. A computer program provided good estimates of the engine performance and of thrust at maximum rating for each exhaust configuration. The internal performance of two different-shaped core nozzles for confluent-flow configurations was determined to be satisfactory. Pressure and temperature surveys were made with a traversing probe in the exhaust-nozzle flow for some confluent-flow configurations. The survey data at the mixing plane, plus the measured flow rates, were used to calculate the static-pressure variation along the exhaust nozzle length. The computed pressures compared well with experimental wall static-pressure data. External-flow surveys were made, for some confluent-flow configurations, with a large fixed rake at various locations in the exhaust plume.

  7. An approximate theoretical method for modeling the static thrust performance of non-axisymmetric two-dimensional convergent-divergent nozzles. M.S. Thesis - George Washington Univ.

    NASA Technical Reports Server (NTRS)

    Hunter, Craig A.

    1995-01-01

    An analytical/numerical method has been developed to predict the static thrust performance of non-axisymmetric, two-dimensional convergent-divergent exhaust nozzles. Thermodynamic nozzle performance effects due to over- and underexpansion are modeled using one-dimensional compressible flow theory. Boundary layer development and skin friction losses are calculated using an approximate integral momentum method based on the classic karman-Polhausen solution. Angularity effects are included with these two models in a computational Nozzle Performance Analysis Code, NPAC. In four different case studies, results from NPAC are compared to experimental data obtained from subscale nozzle testing to demonstrate the capabilities and limitations of the NPAC method. In several cases, the NPAC prediction matched experimental gross thrust efficiency data to within 0.1 percent at a design NPR, and to within 0.5 percent at off-design conditions.

  8. Flight Avionics Sequencing Telemetry (FAST) DIV Latching Display

    NASA Technical Reports Server (NTRS)

    Moore, Charlotte

    2010-01-01

    The NASA Engineering (NE) Directorate at Kennedy Space Center provides engineering services to major programs such as: Space Shuttle, Inter national Space Station, and the Launch Services Program (LSP). The Av ionics Division within NE, provides avionics and flight control syste ms engineering support to LSP. The Launch Services Program is respons ible for procuring safe and reliable services for transporting critical, one of a kind, NASA payloads into orbit. As a result, engineers mu st monitor critical flight events during countdown and launch to asse ss anomalous behavior or any unexpected occurrence. The goal of this project is to take a tailored Systems Engineering approach to design, develop, and test Iris telemetry displays. The Flight Avionics Sequen cing Telemetry Delta-IV (FAST-D4) displays will provide NASA with an improved flight event monitoring tool to evaluate launch vehicle heal th and performance during system-level ground testing and flight. Flight events monitored will include data from the Redundant Inertial Fli ght Control Assembly (RIFCA) flight computer and launch vehicle comma nd feedback data. When a flight event occurs, the flight event is ill uminated on the display. This will enable NASA Engineers to monitor c ritical flight events on the day of launch. Completion of this project requires rudimentary knowledge of launch vehicle Guidance, Navigatio n, and Control (GN&C) systems, telemetry, and console operation. Work locations for the project include the engineering office, NASA telem etry laboratory, and Delta launch sites.

  9. Effects of mother-infant skin-to-skin contact on severe latch-on problems in older infants: a randomized trial

    PubMed Central

    2013-01-01

    Background Infants with latch-on problems cause stress for parents and staff, often resulting in early termination of breastfeeding. Healthy newborns experiencing skin-to-skin contact at birth are pre-programmed to find the mother’s breast. This study investigates if skin-to-skin contact between mothers with older infants having severe latching on problems would resolve the problem. Methods Mother-infant pairs with severe latch-on problems, that were not resolved during screening procedures at two maternity hospitals in Stockholm 1998–2004, were randomly assigned to skin-to-skin contact (experimental group) or not (control group) during breastfeeding. Breastfeeding counseling was given to both groups according to a standard model. Participants were unaware of their treatment group. Objectives were to compare treatment groups concerning the proportion of infants regularly latching on, the time from intervention to regular latching on and maternal emotions and pain before and during breastfeeding. Results On hundred and three mother-infant pairs with severe latch-on problems 1–16 weeks postpartum were randomly assigned and analyzed. There was no significant difference between the groups in the proportion of infants starting regular latching-on (75% experimental group, vs. 86% control group). Experimental group infants, who latched on, had a significantly shorter median time from start of intervention to regular latching on than control infants, 2.0 weeks (Q1 = 1.0, Q3 = 3.7) vs. 4.7 weeks (Q1 = 2.0, Q3 = 8.0), (p-value = 0.020). However, more infants in the experimental group (94%), with a history of “strong reaction” during “hands-on latch intervention”, latched-on within 3 weeks compared to 33% in the control infants (Fisher Exact test p-value = 0.0001). Mothers in the experimental group (n = 53) had a more positive breastfeeding experience according to the Breastfeeding Emotional Scale during the intervention than mothers in the control group (n = 50

  10. Design of High Speed and Low Offset Dynamic Latch Comparator in 0.18 µm CMOS Process

    PubMed Central

    Rahman, Labonnah Farzana; Reaz, Mamun Bin Ibne; Yin, Chia Chieu; Ali, Mohammad Alauddin Mohammad; Marufuzzaman, Mohammad

    2014-01-01

    The cross-coupled circuit mechanism based dynamic latch comparator is presented in this research. The comparator is designed using differential input stages with regenerative S-R latch to achieve lower offset, lower power, higher speed and higher resolution. In order to decrease circuit complexity, a comparator should maintain power, speed, resolution and offset-voltage properly. Simulations show that this novel dynamic latch comparator designed in 0.18 µm CMOS technology achieves 3.44 mV resolution with 8 bit precision at a frequency of 50 MHz while dissipating 158.5 µW from 1.8 V supply and 88.05 µA average current. Moreover, the proposed design propagates as fast as 4.2 nS with energy efficiency of 0.7 fJ/conversion-step. Additionally, the core circuit layout only occupies 0.008 mm2. PMID:25299266

  11. A new latch-free LIGBT on SOI with very high current density and low drive voltage

    NASA Astrophysics Data System (ADS)

    Olsson, J.; Vestling, L.; Eklund, K.-H.

    2016-01-01

    A new latch-free LIGBT on SOI is presented. The new device combines advantages from both LDMOS as well as LIGBT technologies; high breakdown voltage, high drive current density, low control voltages, at the same time eliminating latch-up problems. The new LIGBT has the unique property of independent scaling of the input control device, i.e. LDMOS, and the output part of the device, i.e. the p-n-p part. This allows for additional freedom in designing and optimizing the device properties. Breakdown voltage of over 200 V, on-state current density over 3 A/mm, specific on-resistance below 190 mΩ mm2, and latch-free operation is demonstrated.

  12. Static thrust-vectoring performance of nonaxisymmetric convergent-divergent nozzles with post-exit yaw vanes. M.S. Thesis - George Washington Univ., Aug. 1988

    NASA Technical Reports Server (NTRS)

    Foley, Robert J.; Pendergraft, Odis C., Jr.

    1991-01-01

    A static (wind-off) test was conducted in the Static Test Facility of the 16-ft transonic tunnel to determine the performance and turning effectiveness of post-exit yaw vanes installed on two-dimensional convergent-divergent nozzles. One nozzle design that was previously tested was used as a baseline, simulating dry power and afterburning power nozzles at both 0 and 20 degree pitch vectoring conditions. Vanes were installed on these four nozzle configurations to study the effects of vane deflection angle, longitudinal and lateral location, size, and camber. All vanes were hinged at the nozzle sidewall exit, and in addition, some were also hinged at the vane quarter chord (double-hinged). The vane concepts tested generally produced yaw thrust vectoring angles much less than the geometric vane angles, for (up to 8 percent) resultant thrust losses. When the nozzles were pitch vectored, yawing effectiveness decreased as the vanes were moved downstream. Thrust penalties and yawing effectiveness both decreased rapidly as the vanes were moved outboard (laterally). Vane length and height changes increased yawing effectiveness and thrust ratio losses, while using vane camber, and double-hinged vanes increased resultant yaw angles by 50 to 100 percent.

  13. Method and Apparatus for Reducing the Vulnerability of Latches to Single Event Upsets

    NASA Technical Reports Server (NTRS)

    Shuler, Robert L., Jr. (Inventor)

    2002-01-01

    A delay circuit includes a first network having an input and an output node, a second network having an input and an output, the input of the second network being coupled to the output node of the first network. The first network and the second network are configured such that: a glitch at the input to the first network having a length of approximately one-half of a standard glitch time or less does not cause the voltage at the output of the second network to cross a threshold, a glitch at the input to the first network having a length of between approximately one-half and two standard glitch times causes the voltage at the output of the second network to cross the threshold for less than the length of the glitch, and a glitch at the input to the first network having a length of greater than approximately two standard glitch times causes the voltage at the output of the second network to cross the threshold for approximately the time of the glitch. The method reduces the vulnerability of a latch to single event upsets. The latch includes a gate having an input and an output and a feedback path from the output to the input of the gate. The method includes inserting a delay into the feedback path and providing a delay in the gate.

  14. Method and Apparatus for Reducing the Vulnerability of Latches to Single Event Upsets

    NASA Technical Reports Server (NTRS)

    Shuler, Robert L., Jr. (Inventor)

    2002-01-01

    A delay circuit includes a first network having an input and an output node, a second network having an input and an output, the input of the second network being coupled to the output node of the first network. The first network and the second network are configured such that: a glitch at the input to the first network having a length of approximately one-half of a standard glitch time or less does not cause tile voltage at the output of the second network to cross a threshold, a glitch at the input to the first network having a length of between approximately one-half and two standard glitch times causes the voltage at the output of the second network to cross the threshold for less than the length of the glitch, and a glitch at the input to the first network having a length of greater than approximately two standard glitch times causes the voltage at the output of the second network to cross the threshold for approximately the time of the glitch. A method reduces the vulnerability of a latch to single event upsets. The latch includes a gate having an input and an output and a feedback path from the output to the input of the gate. The method includes inserting a delay into the feedback path and providing a delay in the gate.

  15. Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore.

    PubMed

    Lo, Kin Hing; Kontis, Konstantinos

    2016-01-01

    An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test. PMID:27128913

  16. Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore

    PubMed Central

    Lo, Kin Hing; Kontis, Konstantinos

    2016-01-01

    An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test. PMID:27128913

  17. Static internal performance of ventral and rear nozzle concepts for short-takeoff and vertical-landing aircraft

    NASA Technical Reports Server (NTRS)

    Re, Richard J.; Carson, George T., Jr.

    1991-01-01

    The internal performance of two exhaust system concepts applicable to single-engine short-take-off and vertical-landing tactical fighter configurations was investigated. These concepts involved blocking (or partially blocking) tailpipe flow to the rear (cruise) nozzle and diverting it through an opening to a ventral nozzle exit for vertical thrust. A set of variable angle vanes at the ventral nozzle exit were used to vary ventral nozzle thrust angle between 45 and 110 deg relative to the positive axial force direction. In the vertical flight mode the rear nozzle (or tailpipe flow to it) was completely blocked. In the transition flight mode flow in the tailpipe was split between the rear and ventral nozzles and the flow was vectored at both exits for aircraft control purposes through this flight regime. In the cruise flight mode the ventral nozzle was sealed and all flow exited through the rear nozzle.

  18. The design and development of a miniature bi-stable latching solenoid valve for low thrust resistojets

    NASA Technical Reports Server (NTRS)

    Lynch, R. A.

    1972-01-01

    The design approach and development demonstration are presented for a flightweight, miniature, magnetic latching shutoff valve, suitable for use with the ruggedized H2 and NH3 resistojet and the biowaste resistojet. The design criteria established provided for compatibility with specified ruggedized resistojet propellants as well as the biowaste and other propulsion system propellants.

  19. Effects of internal yaw-vectoring devices on the static performance of a pitch-vectoring nonaxisymmetric convergent-divergent nozzle

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.

    1993-01-01

    An investigation was conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to evaluate the internal performance of a nonaxisymmetric convergent divergent nozzle designed to have simultaneous pitch and yaw thrust vectoring capability. This concept utilized divergent flap deflection for thrust vectoring in the pitch plane and flow-turning deflectors installed within the divergent flaps for yaw thrust vectoring. Modifications consisting of reducing the sidewall length and deflecting the sidewall outboard were investigated as means to increase yaw-vectoring performance. This investigation studied the effects of multiaxis (pitch and yaw) thrust vectoring on nozzle internal performance characteristics. All tests were conducted with no external flow, and nozzle pressure ratio was varied from 2.0 to approximately 13.0. The results indicate that this nozzle concept can successfully generate multiaxis thrust vectoring. Deflection of the divergent flaps produced resultant pitch vector angles that, although dependent on nozzle pressure ratio, were nearly equal to the geometric pitch vector angle. Losses in resultant thrust due to pitch vectoring were small or negligible. The yaw deflectors produced resultant yaw vector angles up to 21 degrees that were controllable by varying yaw deflector rotation. However, yaw deflector rotation resulted in significant losses in thrust ratios and, in some cases, nozzle discharge coefficient. Either of the sidewall modifications generally reduced these losses and increased maximum resultant yaw vector angle. During multiaxis (simultaneous pitch and yaw) thrust vectoring, little or no cross coupling between the thrust vectoring processes was observed.

  20. Screening of nanosatellite microprocessors using californium single-event latch-up test results

    NASA Astrophysics Data System (ADS)

    Tomioka, Takahiro; Okumura, Yuta; Masui, Hirokazu; Takamiya, Koichi; Cho, Mengu

    2016-09-01

    A single-event latch-up (SEL) test using a 252Cf radioisotope was carried out. The results were compared with those of a proton test and from observation in orbit. A radioisotope can reproduce phenomena observed in orbit that are caused by protons. Considering the inexpensive nature of the 252Cf test, it is more suitable for nanosatellites that require low cost and fast delivery. A SEL occurrence rate of a commercial-off-the-shelf microprocessor was derived from the ground test results. The 252Cf test provided a SEL rate approximately 1×106 times greater than that in orbit. This data can be used to derive the minimum SEL occurrence rate in orbit and help satellite designers to evaluate the risk of SEL and take measures if necessary.

  1. Static and transient performance of YF-102 engine with up to 14 percent core airbleed for the quiet short-haul research aircraft

    NASA Technical Reports Server (NTRS)

    Mcardle, J. G.; Homyak, L.; Moore, A. S.

    1980-01-01

    An outdoor static test stand was used to measure the steady-state and transient performance of the YF-102 turbofan engine with core airbleed. The test configuration included a bellmouth inlet and a confluent-flow exhaust system similar in size to the quiet short-haul research aircraft (QSRA) exhaust system. For the steady-state tests, the engine operated satisfactorily with core bleed up to 14 percent of the core inlet flow. For the transient tests the engine accelerated and decelerated satisfactorily with no core bleed and with core bleed up to 11 percent of the core inlet flow (maximum tested). For some of the tests the core-bleed flow rate was scheduled to vary with fan discharge pressure, to simulate the QSRA bleed requirements. No stability, surge, stall, overtemperature, combustor flameout, or other operating problems were encountered in any of the tests. Steady-state and transient engine performance data are presented in graphs, and fuel-control trajectories for typical transient tests are shown.

  2. Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    2000-01-01

    The NASA Langley Configuration Aerodynamics Branch has conducted an experimental investigation to study the static performance of innovative thrust reverser concepts applicable to high-bypass-ratio turbofan engines. Testing was conducted on a conventional separate-flow exhaust system configuration, a conventional cascade thrust reverser configuration, and six innovative thrust reverser configurations. The innovative thrust reverser configurations consisted of a cascade thrust reverser with porous fan-duct blocker, a blockerless thrust reverser, two core-mounted target thrust reversers, a multi-door crocodile thrust reverser, and a wing-mounted thrust reverser. Each of the innovative thrust reverser concepts offer potential weight savings and/or design simplifications over a conventional cascade thrust reverser design. Testing was conducted in the Jet-Exit Test Facility at NASA Langley Research Center using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0. All tests were conducted with no external flow and cold, high-pressure air was used to simulate core and fan exhaust flows. Results show that the innovative thrust reverser concepts achieved thrust reverser performance levels which, when taking into account the potential for system simplification and reduced weight, may make them competitive with, or potentially more cost effective than current state-of-the-art thrust reverser systems.

  3. Static Performance of Six Innovative Thrust Reverser Concepts for Subsonic Transport Applications: Summary of the NASA Langley Innovative Thrust Reverser Test Program

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Yetter, Jeffrey A.

    2000-01-01

    The NASA Langley Configuration Aerodynamics Branch has conducted an experimental investigation to study the static performance of innovative thrust reverser concepts applicable to high-bypass-ratio turbofan engines. Testing was conducted on a conventional separate-flow exhaust system configuration, a conventional cascade thrust reverser configuration, and six innovative thrust reverser configurations. The innovative thrust reverser configurations consisted of a cascade thrust reverser with porous fan-duct blocker, a blockerless thrust reverser, two core-mounted target thrust reversers, a multi-door crocodile thrust reverser, and a wing-mounted thrust reverser. Each of the innovative thrust reverser concepts offer potential weight savings and/or design simplifications over a conventional cascade thrust reverser design. Testing was conducted in the Jet-Exit Test Facility at NASA Langley Research Center using a 7.9%-scale exhaust system model with a fan-to-core bypass ratio of approximately 9.0. All tests were conducted with no external flow and cold, high-pressure air was used to simulate core and fan exhaust flows. Results show that the innovative thrust reverser concepts achieved thrust reverser performance levels which, when taking into account the potential for system simplification and reduced weight, may make them competitive with, or potentially more cost effective than current state-of-the-art thrust reverser systems. All data gathered in this investigation are contained in the CD-ROM.

  4. Static and Dynamic Performance of Complementary Inverters Based on Nanosheet α-MoTe2 p-Channel and MoS2 n-Channel Transistors.

    PubMed

    Pezeshki, Atiye; Hosseini Shokouh, Seyed Hossein; Jeon, Pyo Jin; Shackery, Iman; Kim, Jin Sung; Oh, Il-Kwon; Jun, Seong Chan; Kim, Hyungjun; Im, Seongil

    2016-01-26

    Molybdenum ditelluride (α-MoTe2) is an emerging transition-metal dichalcogenide (TMD) semiconductor that has been attracting attention due to its favorable optical and electronic properties. Field-effect transistors (FETs) based on few-layer α-MoTe2 nanosheets have previously shown ambipolar behavior with strong p-type and weak n-type conduction. We have employed a direct imprinting technique following mechanical nanosheet exfoliation to fabricate high-performance complementary inverters using α-MoTe2 as the semiconductor for the p-channel FETs and MoS2 as the semiconductor for the n-channel FETs. To avoid ambipolar behavior and produce α-MoTe2 FETs with clean p-channel characteristics, we have employed the high-workfunction metal platinum for the source and drain contacts. As a result, our α-MoTe2 nanosheet p-channel FETs show hole mobilities up to 20 cm(2)/(V s), on/off ratios up to 10(5), and a subthreshold slope of 255 mV/decade. For our complementary inverters composed of few-layer α-MoTe2 p-channel FETs and MoS2 n-channel FETs we have obtained voltage gains as high as 33, noise margins as high as 0.38 VDD, a switching delay of 25 μs, and a static power consumption of a few nanowatts. PMID:26631357

  5. Aerodynamic Performance and Static Stability at Mach Number 3.3 of an Aircraft Configuration Employing Three Triangular Wing Panels and a Body Equal Length

    NASA Technical Reports Server (NTRS)

    James, Carlton S.

    1960-01-01

    An aircraft configuration, previously conceived as a means to achieve favorable aerodynamic stability characteristics., high lift-drag ratio, and low heating rates at high supersonic speeds., was modified in an attempt to increase further the lift-drag ratio without adversely affecting the other desirable characteristics. The original configuration consisted of three identical triangular wing panels symmetrically disposed about an ogive-cylinder body equal in length to the root chord of the panels. This configuration was modified by altering the angular disposition of the wing panels, by reducing the area of the panel forming the vertical fin, and by reshaping the body to produce interference lift. Six-component force and moment tests of the modified configuration at combined angles of attack and sideslip were made at a Mach number of 3.3 and a Reynolds number of 5.46 million. A maximum lift-drag ratio of 6.65 (excluding base drag) was measured at a lift coefficient of 0.100 and an angle of attack of 3.60. The lift-drag ratio remained greater than 3 up to lift coefficient of 0.35. Performance estimates, which predicted a maximum lift-drag ratio for the modified configuration 27 percent greater than that of the original configuration, agreed well with experiment. The modified configuration exhibited favorable static stability characteristics within the test range. Longitudinal and directional centers of pressure were slightly aft of the respective centroids of projected plan-form and side area.

  6. Static Scale Conversion (SSC)

    SciTech Connect

    2007-01-19

    The Static Scale Conversion (SSC) software is a unique enhancement to the AIMVEE system. It enables a SSC to weigh and measure vehicles and cargo dynamically (i.e., as they pass over the large scale. Included in the software is the AIMVEE computer code base. The SSC and AIMVEE computer system electronically continue to retrieve deployment information, identify vehicle automatically and determine total weight, individual axle weights, axle spacing and center-of-balance for any wheeled vehicle in motion. The AIMVEE computer code system can also perform these functions statically for both wheel vehicles and cargo with information. The AIMVEE computer code system incorporates digital images and applies cubing algorithms to determine length, width, height for cubic dimensions of both vehicle and cargo. Once all this information is stored, it electronically links to data collection and dissemination systems to provide “actual” weight and measurement information for planning, deployment, and in-transit visibility.

  7. Static Scale Conversion (SSC)

    Energy Science and Technology Software Center (ESTSC)

    2007-01-19

    The Static Scale Conversion (SSC) software is a unique enhancement to the AIMVEE system. It enables a SSC to weigh and measure vehicles and cargo dynamically (i.e., as they pass over the large scale. Included in the software is the AIMVEE computer code base. The SSC and AIMVEE computer system electronically continue to retrieve deployment information, identify vehicle automatically and determine total weight, individual axle weights, axle spacing and center-of-balance for any wheeled vehicle inmore » motion. The AIMVEE computer code system can also perform these functions statically for both wheel vehicles and cargo with information. The AIMVEE computer code system incorporates digital images and applies cubing algorithms to determine length, width, height for cubic dimensions of both vehicle and cargo. Once all this information is stored, it electronically links to data collection and dissemination systems to provide “actual” weight and measurement information for planning, deployment, and in-transit visibility.« less

  8. Polarization encoded all-optical quaternary R-S flip-flop using binary latch

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath; Chakraborty, Ajoy Kumar

    2009-04-01

    The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper.

  9. Stückelberg interference in a superconducting qubit under periodic latching modulation

    NASA Astrophysics Data System (ADS)

    Silveri, M. P.; Kumar, K. S.; Tuorila, J.; Li, J.; Vepsäläinen, A.; Thuneberg, E. V.; Paraoanu, G. S.

    2015-04-01

    When the level separation of a qubit is modulated periodically across an avoided crossing, tunneling to the excited state—and consequently Landau-Zener-Stückelberg interference—can occur. The types of modulation studied so far correspond to a continuous change of the level separation. Here we study periodic latching modulation, in which the level separation is switched abruptly between two values and is kept constant otherwise. In this case, the conventional approach based on the asymptotic Landau-Zener formula for transition probabilities is not applicable. We develop a novel adiabatic-impulse model for the evolution of the system and derive the resonance conditions. Additionally, we derive analytical results based on the rotating-wave approximation (RWA). The adiabatic-impulse model and the RWA results are compared with those of a full numerical simulation. These theoretical predictions are tested in an experimental setup consisting of a transmon whose flux bias is modulated with a square wave form. A rich spectrum is observed, with distinctive features correspoding to two regimes: slow-modulation and fast-modulation. These experimental results are shown to be in very good agreement with the theoretical models. Also, differences with respect to the well known case of sinusoidal modulation are discussed, both theoretically and experimentally.

  10. Psychometric Evaluation of 5- and 4-Item Versions of the LATCH Breastfeeding Assessment Tool during the Initial Postpartum Period among a Multiethnic Population

    PubMed Central

    Htun, Tha Pyai; Lim, Peng Im; Ho-Lim, Sarah

    2016-01-01

    Objectives The aim of this study was to evaluate the internal consistency, structural validity, sensitivity and specificity of the 5- and 4-item versions of the LATCH assessment tool among a multiethnic population in Singapore. Methods The study was a secondary analysis of a subset of data (n = 907) from our previous breastfeeding survey from 2013 to 2014. The internal consistency of the LATCH was examined using Cronbach’s alpha. The structural validity was assessed using an exploratory factor analysis (EFA), and the proposed factors were confirmed by confirmatory factor analysis (CFA) using separate samples. Receiver operating characteristic analysis was used to evaluate the sensitivity and specificity of the LATCH score thresholds for predicting non-exclusive breastfeeding. Results The Cronbach’s alpha values of the 5- and 4-item LATCH assessments were 0.70 and 0.74, respectively. The EFA demonstrated a one-factor structure for the 5- and 4-item LATCH assessments among a randomized split of 334 vaginally delivered women. Two CFA of the 4-item LATCH demonstrated better fit indices of the models compared to the two CFA of the 5-item LATCH among another randomized split of 335 vaginally delivered women and 238 cesarean delivered women. Using cutoffs of 5.5 and 3.5 were recommended when predicting non-exclusive breastfeeding for 5- and 4-item versions of the LATCH assessment among vaginally delivered women (n = 669), with satisfactory sensitivities (94% and 95%), low specificities (0% and 2%), low positive predictive values (25%) and negative predictive values (20% and 47%). A cutoff of 5.5 was recommended to predict non-exclusive breastfeeding for 5- and 4-item versions among cesarean delivered women (n = 238) with satisfactory sensitivities (93% and 98%), low specificities (4% and 9%), low positive predictive values (41%) and negative predictive values (65% and 75%). Therefore, the tool has good sensitivity but poor specificity, positive and negative predictive

  11. Effects of non-latching blast valves on the source term and consequences of the design-basis accidents in the Device Assembly Facility (DAF)

    SciTech Connect

    Nguyen, D.H.

    1993-08-01

    The analysis of the Design-Basis Accidents (DBA) involving high explosives (HE) and Plutonium (Pu) in the assembly cell of the Device Assembly Facility (DAF), which was completed earlier, assumed latching blast valves in the ventilation system of the assembly cell. Latching valves effectively sealed a release path through the ventilation duct system. However, the blast valves in the assembly cell, as constructed are actually non-latching valves, and would reopen when the gas pressure drops to 0.5 psi above one atmosphere. Because the reopening of the blast valves provides an additional release path to the environment, and affects the material transport from the assembly cell to other DAF buildings, the DOE/NV DAF management has decided to support an additional analysis of the DAF`s DBA to account for the effects of non-latching valves. Three cases were considered in the DAF`s DBA, depending on the amount of HE and Pu involved, as follows: Case 1 -- 423 {number_sign}HE, 16 kg Pu; Case 2 -- 150 {number_sign}HE 10 kg Pu; Case 3 -- 55 {number_sign}HE 5 kg Pu. The results of the analysis with non-latching valves are summarized.

  12. Magnetized static black Saturn

    SciTech Connect

    Yazadjiev, Stoytcho S.

    2008-06-15

    We present a new static solution to the 5D Einstein-Maxwell equations describing a static black hole surrounded by a nonrotating dipole black ring. The configuration is kept in equilibrium by an external magnetic field interacting with the dipole charge of the black ring. The properties of the black Saturn-like configuration are studied and the basic physical quantities are calculated. The solution demonstrates 2-fold continuous nonuniqueness of the 5D magnetized static neutral black objects for fixed total mass and Melvin background.

  13. Discovery in Statics

    NASA Astrophysics Data System (ADS)

    Makarov, Sergey

    2013-11-01

    This article described the opening of a new law in fundamental physics, namely the law of the formation of an endless series of suspension (cable-stayed) networks coatings. Opening relates to the mechanics, section of statics.

  14. Incorporating Peatland Plant Communities into the Enzymic 'Latch' Hypothesis: Can Vegetation Influence Carbon Storage Mechanisms?

    NASA Astrophysics Data System (ADS)

    Romanowicz, K. J.; Daniels, A. L.; Potvin, L. R.; Kane, E. S.; Kolka, R. K.; Chimner, R. A.; Lilleskov, E. A.

    2012-12-01

    High water table conditions in peatland ecosystems are known to favor plant production over decomposition and carbon is stored. Dominant plant communities change in response to water table but little is know of how these changes affect belowground carbon storage. One hypothesis known as the enzymic 'latch' proposed by Freeman et al. suggests that oxygen limitations due to high water table conditions inhibit microorganisms from synthesizing specific extracellular enzymes essential for carbon and nutrient mineralization, allowing carbon to be stored as decomposition is reduced. Yet, this hypothesis excludes plant community interactions on carbon storage. We hypothesize that the dominant vascular plant communities, sedges and ericaceous shrubs, will have inherently different effects on peatland carbon storage, especially in response to declines in water table. Sedges greatly increase in abundance following water table decline and create extensive carbon oxidation and mineralization hotspots through the production of deep roots with aerenchyma (air channels in roots). Increased oxidation may enhance aerobic microbial activity including increased enzyme activity, leading to peat subsidence and carbon loss. In contrast, ericaceous shrubs utilize enzymatically active ericoid mycorrhizal fungi that suppress free-living heterotrophs, promoting decreased carbon mineralization by mediating changes in rhizosphere microbial communities and enzyme activity regardless of water table declines. Beginning May 2010, bog monoliths were harvested, housed in mesocosm chambers, and manipulated into three vegetation treatments: unmanipulated (+sedge, +Ericaceae), sedge (+sedge, -Ericaceae), and Ericaceae (-sedge, +Ericaceae). Following vegetation manipulations, two distinct water table manipulations targeting water table seasonal profiles were implemented: (low intra-seasonal variability, higher mean water table; high intra-seasonal variability, lower mean water table). In 2012, peat

  15. Breaking The Enzymatic Latch: Do Anaerobic Conditions Constrain Decomposition In Humid Tropical Forest Soil?

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.

    2011-12-01

    Anaerobic conditions have been proposed to impose a "latch" on soil organic matter decomposition by inhibiting the activity of extracellular enzymes that catalyze the transformation of organic polymers into monomers for microbial assimilation. Here, we tested the hypothesis that anaerobiosis inhibits soil hydrolytic enzyme activity in a humid tropical forest ecosystem in Puerto Rico. We sampled surface and sub-surface soil from each of 59 plots (n = 118) stratified across distinct topographical zones (ridges, slopes, and valleys) known to vary in soil oxygen (O2) concentrations, and measured the potential activity of five hydrolytic enzymes that decompose carbon (C), nitrogen (N), and phosphorus (P) substrates. We measured reduced iron (Fe (II)) concentrations in soil extractions to provide a spatially and temporally integrated index of anaerobic microbial activity, since iron oxides constitute the dominant anaerobic terminal electron acceptor in this ecosystem. Surprisingly, we observed positive relationships between Fe (II) concentrations and the activity of all enzymes that we assayed. Linear mixed effects models that included Fe (II) concentration, topographic position, and their interaction explained between 30 to 70 % of the variance of enzyme activity of β-1,4-glucosidase, β-cellobiohydrolase, β-xylosidase, N-acetylglucosaminidase, and acid phosphatase. Soils from ridges and slopes contained between 10 and 800 μg Fe (II) g-1 soil, and exhibited consistently positive relationships (p < 0.0001) between Fe (II) and enzyme activity. Valley soils did not display significant relationships between enzyme activity and Fe (II), although they displayed variation in soil Fe (II) concentrations similar to ridges and slopes. Overall, valleys exhibited lower enzyme activity and lower Fe (II) concentrations than ridges or slopes, possibly related to decreased root biomass and soil C. Our data provide no indication that anaerobiosis suppresses soil enzyme activity, but

  16. Teaching home safety and survival skills to latch-key children: a comparison of two manuals and methods.

    PubMed Central

    Peterson, L

    1984-01-01

    I evaluated the influence of two training manuals on latch-key children's acquisition of home safety and survival skills. The widely used, discussion-oriented "Prepared for Today" manual was compared with a behaviorally oriented "Safe at Home" manual. Data were scored by response criteria developed by experts and by parents' and experts' ratings of children's spontaneous answers. With both methods of scoring, three behaviorally trained children demonstrated clear and abrupt increases in skill following training in each of seven trained modules, and these increases largely persisted in real world generalization probes and at 5-month follow-up. Smaller and less stable increases in skill were found in the three discussion-trained children across the seven modules; lower skill levels were also seen in real world generalization probes and at follow-up. Neither group of children demonstrated skill increases in home safety areas that were not explicitly trained. Both training methods produced small decreases in children's self-report of general anxiety and anxiety concerning home safety. Results are discussed in terms of their implications for cost-effective training of latch-key children. PMID:6511698

  17. Static Detection of Disassembly Errors

    SciTech Connect

    Krishnamoorthy, Nithya; Debray, Saumya; Fligg, Alan K

    2009-10-13

    Static disassembly is a crucial first step in reverse engineering executable files, and there is a consider- able body of work in reverse-engineering of binaries, as well as areas such as semantics-based security anal- ysis, that assumes that the input executable has been correctly disassembled. However, disassembly errors, e.g., arising from binary obfuscations, can render this assumption invalid. This work describes a machine- learning-based approach, using decision trees, for stat- ically identifying possible errors in a static disassem- bly; such potential errors may then be examined more closely, e.g., using dynamic analyses. Experimental re- sults using a variety of input executables indicate that our approach performs well, correctly identifying most disassembly errors with relatively few false positives.

  18. Observing the Forces Involved in Static Friction under Static Situations

    ERIC Educational Resources Information Center

    Kaplan, Daniel

    2013-01-01

    Static friction is an important concept in introductory physics. Later in the year students apply their understanding of static friction under more complex conditions of static equilibrium. Traditional lab demonstrations in this case involve exceeding of the maximum level of static friction, resulting in the "onset of motion." (Contains…

  19. Relative performances of artificial neural network and regression mapping tools in evaluation of spinal loads and muscle forces during static lifting.

    PubMed

    Arjmand, N; Ekrami, O; Shirazi-Adl, A; Plamondon, A; Parnianpour, M

    2013-05-31

    Two artificial neural networks (ANNs) are constructed, trained, and tested to map inputs of a complex trunk finite element (FE) model to its outputs for spinal loads and muscle forces. Five input variables (thorax flexion angle, load magnitude, its anterior and lateral positions, load handling technique, i.e., one- or two-handed static lifting) and four model outputs (L4-L5 and L5-S1 disc compression and anterior-posterior shear forces) for spinal loads and 76 model outputs (forces in individual trunk muscles) are considered. Moreover, full quadratic regression equations mapping input-outputs of the model developed here for muscle forces and previously for spine loads are used to compare the relative accuracy of these two mapping tools (ANN and regression equations). Results indicate that the ANNs are more accurate in mapping input-output relationships of the FE model (RMSE= 20.7 N for spinal loads and RMSE= 4.7 N for muscle forces) as compared to regression equations (RMSE= 120.4 N for spinal loads and RMSE=43.2 N for muscle forces). Quadratic regression equations map up to second order variations of outputs with inputs while ANNs capture higher order variations too. Despite satisfactory achievement in estimating overall muscle forces by the ANN, some inadequacies are noted including assigning force to antagonistic muscles with no activity in the optimization algorithm of the FE model or predicting slightly different forces in bilateral pair muscles in symmetric lifting activities. Using these user-friendly tools spine loads and trunk muscle forces during symmetric and asymmetric static lifts can be easily estimated. PMID:23541615

  20. Architectures for statically scheduled dataflow

    SciTech Connect

    Lee, E.A.; Bier, J.C. )

    1990-12-01

    When dataflow program graphs can be statically scheduled, little run-time overhead (software or hardware) is necessary. This paper describes a class of parallel architectures consisting of von Neumann processors and one or more shared memories, where the order of shared- memory access is determined at compile time and enforced at run time. The architecture is extremely lean in hardware, yet for a set of important applications it can perform as well as any shared-memory architecture. Dataflow graphs can be mapped onto it statically. Furthermore, it supports shared data structures without the run-time overhead of I-structures. A software environment has been constructed that automatically maps signal processing applications onto a simulation of such an architecture, where the architecture is implemented using Motorola DSP96002 microcomputers. Static (compile-time) scheduling is possible for a subclass of dataflow program graphs where the firing pattern of actors is data independent. This model is suitable for digital signal processing and some other scientific computation. It supports recurrences, manifest iteration, and conditional assignment. However, it does not support true recursion, data-dependent iteration, or conditional evaluation. An effort is under way to weaken the constraints of the model to determine the implications for hardware design.

  1. Why Static Clings

    ERIC Educational Resources Information Center

    Naab, Laurie; Henry, David

    2009-01-01

    Using Wiggins and McTighe's (1998) concept of Big Ideas, the authors planned and designed an electricity investigation to address common student misconceptions about static electricity. With Styrofoam plates and transparent tape, elementary students investigated many properties of electrically charged and uncharged objects in a 5E learning cycle…

  2. I.1. Statics.

    PubMed

    Verkerke, Gijsbertus J; Lee, T Clive

    2010-01-01

    The forces that act on an object determine its dynamic behaviour and defromation. Analysis of all forces and moments is essential. A free-body diagram summarizes all forces and moments that act on an object. To calculate the magnitude of the forces we can use the static equilibrium of forces and moments. PMID:20407182

  3. Static cylindrically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Fjällborg, Mikael

    2007-05-01

    We prove the existence of static solutions to the cylindrically symmetric Einstein Vlasov system, and we show that the matter cylinder has finite extension in two of the three spatial dimensions. The same results are also proved for a quite general class of equations of state for perfect fluids coupled to the Einstein equations, extending the class of equations of state considered by Bicak et al (2004 Class. Quantum Grav.21 1583). We also obtain this result for the Vlasov Poisson system.

  4. A comparative analysis of static and dynamic load balancing strategies

    NASA Technical Reports Server (NTRS)

    Iqbal, M. Ashraf; Bokhari, Shahid H.; Saltz, Joel H.

    1986-01-01

    The problem of uniformly distributing the load of a parallel program over a multiprocessor system was considered. A program was analyzed whose structure permits the computation of the optimal static solution. Then four strategies for load balancing were described and their performance compared. The strategies are: (1) the optimal static assignment algorithm which is guaranteed to yield the best static solution, (2) the static binary dissection method which is very fast but suboptimal, (3) the greedy algorithm, a static fully polynomial time approximation scheme, which estimates the optimal solution to arbitrary accuracy, and (4) the predictive dynamic load balancing heuristic which uses information on the precedence relationships within the program and outperforms any of the static methods. It is also shown that the overhead incurred by the dynamic heuristic is reduced considerably if it is started off with a static assignment provided by either of the three strategies.

  5. PEBBLES Simulation of Static Friction and New Static Friction Benchmark

    SciTech Connect

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2010-05-01

    Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. This paper documents the PEBBLES static friction model. This model uses a three dimensional differential static friction approximation extended from the two dimensional Cundall and Strack model. The derivation of determining the rotational transformation of pebble to pebble static friction force is provided. A new implementation for a differential rotation method for pebble to container static friction force has been created. Previous published methods are insufficient for pebble bed reactor geometries. A new analytical static friction benchmark is documented that can be used to verify key static friction simulation parameters. This benchmark is based on determining the exact pebble to pebble and pebble to container static friction coefficients required to maintain a stable five sphere pyramid.

  6. Thermal Performance of Biological Substance Systems in Vitro Under Static and Dynamic Conditions at the Cryogenic Test Laboratory, NASA Kennedy Space Center, USA

    NASA Technical Reports Server (NTRS)

    Augustynowicz, S. D.; Fesmire, James E.; Steinrock, T. (Technical Monitor)

    2001-01-01

    A unique research program, including a comprehensive study of thermal performance at cryogenic vacuum insulation systems, was performed at the NASA Kennedy Space Center. The main goal was to develop a new soft vacuum system (from 1 torr to 10 torr) that provides an intermediate level of performance (k-value below 4.8 mW/m-K). Liquid nitrogen boil-off methods were used to test conventional materials, novel materials, and certain combinations. The test articles included combinations of aluminum foil, fiberglass paper, polyester fabric, silica aerogel composite blanket, fumed silica, silica aerogel powder, and syntactic foam. A new LCI system was developed at the Cryogenics Test Laboratory. This system performs exceptionally well at soft vacuum levels and nearly as good as an MLI at high vacuum levels. Apparent thermal conductivities for the LCI range from 2 mW/m-K at soft vacuum to 0.1 mW/m-K at high vacuum. Several cryostats were designed, constructed, and calibrated by the Cryogenics Test Laboratory at KSC NASA as part of this research program. The cryostat test apparatus is a liquid nitrogen boil-off calorimeter system for direct measurement of the apparent thermal conductivity at a fixed vacuum level between 5 x 10(exp -5) and 760 torr. The apparatus is also used for transient measurements of temperature profiles. The development of efficient, robust cryogenic insulation systems has been a targeted area of research for a number of years. Improved methods of characterization, testing, and evaluation of complex biological substance systems for cryosurgery and cryobiology are the focus of this paper.

  7. Effect of device geometry on static and dynamic performance of AlGaN/GaN-on-Si high electron mobility transistor

    NASA Astrophysics Data System (ADS)

    Shi, Jin-Shan; Huang, Hong-Fan; Liu, Xiao-Yong; Zhao, Sheng-Xun; Zhang, Lin-Qing; Wang, Peng-Fei

    2016-08-01

    This paper discusses the effects of several geometric parameters in DC and RF performances of AlGaN/GaN high electron mobility transistors (HEMTs) grown on high-resistivity silicon substrates. Those parameters include the dependency of gate length (L g), gate cap length (L cap) and gate-to-source distance (L gs). It is shown that decreasing L g and L gs can both improve maximum drain current and transconductance behaviors. The fabricated 50 μm wide GaN-HEMT exhibits the maximum drain current of 1 A mm‑1 at V g = 2 V and maximum extrinsic transconductance G mmax of 240 mS mm‑1. Besides, decreasing L g and L cap also provides the improvement on current gain frequency (fT ) and maximum oscillation cut off frequency (f MAX). The fT of 40 GHz and f MAX of 55 GHz at V ds = 5 V are demonstrated by GaN-HEMT device featuring L g of 200 nm, L cap of 300 nm and L gs of 1.2 μm, which can realize the compact solid-state power amplifier used in S and C band. However, gate-to-source distance has little effect on RF performance of AlGaN/GaN HEMTs. Those results compared in our study are not only very essential for accurate GaN-based HEMT device modeling and fabrication, but are also vital to better understanding of their device physics.

  8. Effects of a dynamic chair on pelvic mobility, fatigue, and work efficiency during work performed while sitting: a comparison of dynamic sitting and static sitting

    PubMed Central

    Tanoue, Hironori; Mitsuhashi, Toshitaka; Sako, Shunji; Goto, Ryokichi; Nakai, Tomohiro; Inaba, Ryoichi

    2016-01-01

    [Purpose] Working while sitting for long periods can cause lumbar pain, fatigue, and reduced work efficiency. How a dynamic chair with a seat that moves three-dimensionally affects pelvic mobility before and after work, work efficiency, and post-work fatigue were examined. [Subjects and Methods] Subjects were 17 healthy adults (10 males, 7 females, mean age 21.8 ± 2.7 years). Subjects performed a 30-min Kraepelin test under two conditions: sitting in a standard office chair and sitting in a dynamic sitting balance chair. Root mean square (RMS) values of pelvic movement measured by a triaxial accelerometer during 30 minutes of work, finger-floor distance before and after work, lumbar fatigue, and pelvic movement RMS values during finger-floor distance measurement were used as outcome measures. [Results] Pelvic movement RMS values collected every 5 minutes during 30 minutes of work were significantly higher while sitting in the dynamic balance chair. Changes in pelvic movement RMS values during finger-floor distance measurement after work and amount of work performed during 30 minutes were significantly higher and lumbar fatigue was significantly lower for the dynamic balance chair. [Conclusion] Dynamic sitting maintained or increased pelvic flexibility. The dynamic balance chair may effectively help workers work continuously in seated postures with little fatigue. PMID:27390410

  9. Pheromone Static Routing Strategy for Complex Networks

    NASA Astrophysics Data System (ADS)

    Hu, Mao-Bin; Henry, Y. K. Lau; Ling, Xiang; Jiang, Rui

    2012-12-01

    We adopt the concept of using pheromones to generate a set of static paths that can reach the performance of global dynamic routing strategy [Phys. Rev. E 81 (2010) 016113]. The path generation method consists of two stages. In the first stage, a pheromone is dropped to the nodes by packets forwarded according to the global dynamic routing strategy. In the second stage, pheromone static paths are generated according to the pheromone density. The output paths can greatly improve traffic systems' overall capacity on different network structures, including scale-free networks, small-world networks and random graphs. Because the paths are static, the system needs much less computational resources than the global dynamic routing strategy.

  10. Programmable controller with overcurrent latch for constant primary peak current in capacitor-charging FET switcher for Nova

    SciTech Connect

    Mihalka, A.M.

    1983-06-06

    New switching power supplies were designed for the 10 mm laser amplifiers in the Nova Master Oscillator Room. The flashlamp supply must be repratable. Therefore, we designed a constant current, linearly charging power supply. Since it is a capacitor, the load varies throughout the charge cycle. At first the load is great, and di/dt of load current is at a maximum. As the capacitor charges the initial conditions for each cycle change, the power supply in effect sees a smaller capacitance, and di/dt decreases. We need a way of gradually increasing the on-time of the current pulses so that the transistors in the power bridge are turned off when they reach their maximum peak current. The normal current sense response of the control chip is not fast enough to be useful for our application. The deadtime, or the time that all the bridge transistors are turned off, is fixed so that as the pulse width varies so does the period. We end up with a constant peak current, switching power supply whose frequency varies from 50 khz to 20 khz. Finally, an overcurrent latch protects the transistors from bridge or transformer faults. The circuit is described and results are shown.

  11. 40 CFR 53.64 - Test procedure: Static fractionator test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Performance Characteristics of Class II Equivalent Methods for PM2.5 § 53.64 Test procedure: Static... sampler's operating manual referred to in section 7.4.18 of 40 CFR part 50, appendix L. (2) Generate... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Test procedure: Static...

  12. Dynamic performance of the mechanism of an automatically deployable ROPS.

    PubMed

    Etherton, J R; Cutlip, R G; Harris, J R; Ronaghi, M; Means, K H; Howard, S

    2002-02-01

    The mechanism for an automatically deployable ROPS (AutoROPS) has been designed and tested. This mechanism is part of an innovative project to provide passive protection against rollover fatality to operators of new tractors used in both low-clearance and unrestricted-clearance tasks. The device is a spring-action, telescoping structure that releases on signal to pyrotechnic squibs that actuate release pins. Upper post motion begins when the release pins clear an internal piston. The structure extends until the piston impacts an elastomeric ring and latches at the top position. In lab tests the two-post structure consistently deployed in less than 0.3 s and latched securely. Static load tests of the telescoping structure and field upset tests of the fully functional AutoROPS have been successfully completed. PMID:12002370

  13. SEU response of design- and resistor-hardened D-latches in the SA3300 microprocessor

    SciTech Connect

    Sexton, F.W.; Corbett, W.T.; Axness, C.L.; Wunsch, T.F.; Hughes, K.L.; Treece, R.K.; Hass, K.J.; Hash, G.L.; Shaneyfelt, M.R.

    1991-01-01

    The effectiveness of hardening the SA3300 against SEU using design and design-plus-resistor approaches is presented. The full performance and SEU tolerance requirements are met using R{sub fb} {le} 160 k{Omega}. Lumped-parameter circuit simulations are used to analyze results. 10 refs., 5 figs.

  14. Properties of Broezel static probe

    NASA Astrophysics Data System (ADS)

    Gašparovič, Peter; Semrád, Karol; Cúttová, Miroslava

    2016-03-01

    The properties of flat static probe designed by Broezel and used in sailplanes are investigated for its planned use in low speed tunnel. Both the numerical CFD model and experiment in low speed wind tunnel confirm yaw insensitivity of the static pressure measured by the probe. The results indicate that the probe is sufficiently accurate for its planned use in wind tunnel measurements.

  15. Semiconductor ac static power switch

    NASA Technical Reports Server (NTRS)

    Vrancik, J.

    1968-01-01

    Semiconductor ac static power switch has long life and high reliability, contains no moving parts, and operates satisfactorily in severe environments, including high vibration and shock conditions. Due to their resistance to shock and vibration, static switches are used where accidental switching caused by mechanical vibration or shock cannot be tolerated.

  16. NAMING DYNAMIC AND STATIC ACTIONS: NEUROPSYCHOLOGICAL EVIDENCE

    PubMed Central

    Tranel, Daniel; Manzel, Kenneth; Asp, Erik; Kemmerer, David

    2008-01-01

    There has been considerable interest in identifying the neural correlates of action naming, but the bulk of previous work on this topic has utilized static stimuli. Recent research comparing the visual processing of dynamic versus static actions suggests that these two types of stimuli engage largely overlapping neural systems, raising the possibility that the higher-order processing requirements for naming dynamic and static actions might not be very different. To explore this issue in greater depth, we developed the Dynamic Action Naming Test (DANT), which consists of 158 video clips 3–5 sec in length, for each of which the participant is asked to produce the most appropriate verb. We administered the DANT to 78 brain-damaged patients drawn from our Patient Registry, and to a demographically matched group of 50 normal participants. Out of the 16 patients who performed defectively on the DANT, nearly all (15/16) had damage in the left hemisphere. Lesion analysis indicated that the frontal operculum was the most frequent area of damage in the 15 patients; also, damage to the posterolateral temporal-occipital sector (in and near MT) was specifically related to defective dynamic action naming. Most of the brain-damaged participants (n = 71) also received our Static Action Naming Test (SANT), and we found that performances on verb items that were common across the DANT and SANT were highly correlated (R = .91). Moreover, patients who failed the DANT almost invariably also failed the SANT. These findings lend further support to the hypothesis that there is considerable commonality in the neural systems underlying the use of verbs to orally name dynamic and static actions, a conclusion that is in turn compatible with the concept of “representational momentum.” Our results also contribute more generally to the rapidly growing field of research on embodied cognition. PMID:18486456

  17. Static magnetic properties of Maghemite nanoparticles

    NASA Astrophysics Data System (ADS)

    Zulfiqar; Rahman, Muneeb Ur; Usman, M.; Hasanain, Syed Khurshid; Zia-ur-Rahman; Ullah, Amir; Kim, Ill Won

    2014-12-01

    We report the static magnetic properties of Maghemite (γ-Fe2O3) nanoparticles with an average crystallite size of 14 ± 1.8 nm synthesized via a co-precipitation method. The zero-field-cooled (ZFC) and the field-cooled (FC) magnetization measurements were performed using a physical properties measurements system (PPMS) at temperatures from 5 K to 300 K. The ZFC/FC measurements showed a typical superparamagnetic behavior with a narrow size distribution.

  18. Static Analysis of C Programs

    NASA Technical Reports Server (NTRS)

    Venet, Arnaud; Brat, Guillaume

    2003-01-01

    Contents include the following: Motivation. Cost of losing missions. Introduction to Static Analysis:definition, defect classes, applicability issues, specialization, analysis of MPF. C Global Surveyor (CGS): fact sheet, CGS phases, example. Conclusions.

  19. Economics of static VAR compensation

    SciTech Connect

    Alvarado, F.L.; DeMarco, C.; Jung, T.H. . Dept. of Electrical and Computer Engineering)

    1992-09-01

    This project was initiated in anticipation of widened use of static VAR (volt-ampere-reactive) compensation on US bulk-power transmission systems to increase levels of secure power transfer. Project objectives were to deten-nine power system cost savings and reliability benefits resulting from such use. System operating cost and stability probabilities were compared with and without static VAR compensation, applying simulation techniques. For the particular system model studied, there was a 21.4 percent reduction in operating costs taking into account losses added by the static VAR compensator. A procedure was developed to compare instability probabilities for various loadings and static VAR compensator sizes on a power system. For the particular system model studied, the static VAR compensator provided a significant increase in stability but over a narrow range of loading. Static VAR compensation is one of a number of promising FACTS (Flexible AC Transmission System) technologies for handling the demands of increased power transfers on power systems where transmission lines cannot be built or as a short-term altemative to building additional lines.

  20. Static Thrust Analysis of the Lifting Airscrew

    NASA Technical Reports Server (NTRS)

    Knight, Montgomery; Hefner, Ralph A

    1937-01-01

    This report presents the results of a combined theoretical and experimental investigation conducted at the Georgia School of Technology on the static thrust of the lifting air screw of the type used in modern autogiros and helicopters. The theoretical part of this study is based on Glauert's analysis but certain modifications are made that further clarify and simplify the problem. Of these changes the elimination of the solidity as an independent parameter is the most important. The experimental data were obtained from tests on four rotor models of two, four, and five blades and, in general, agree quite well with the theoretical calculations. The theory indicates a method of evaluating scale effects on lifting air screws, and these corrections have been applied to the model results to derive general full-scale static thrust, torque, and figure-of-merit curves for constant-chord, constant-incidence rotors. Convenient charts are included that enable hovering flight performance to be calculated rapidly.

  1. Grayloc seal static tests

    SciTech Connect

    Leisher, W.B.; Biffle, J.H.

    1983-02-01

    A series of evaluation tests was performed on Grayloc seals. Helium service and standard seals, size 292, were used. Measurements were made of axial force and motion, diameter, hoop and axial strain, and helium leak rate. Leak rates were in the 10/sup -6/ atm cc/s range for the helium service seals. Pretest analytical calculations agreed reasonably well with measured makeup forces and deflections.

  2. Static Characteristics of Conical Hydrostatic Journal Bearing Under Micropolar Lubrication

    NASA Astrophysics Data System (ADS)

    Rana, N. K.; Gautam, S. S.; Verma, S.

    2014-08-01

    A theoretical analysis for static characteristics of a conical hydrostatic journal bearing for a multirecess constant flow valve compensated under micropolar lubrication has been carried out in this work. The numerical solution of the modified Reynolds equation for the conical bearing has been done using Finite Element Method (FEM) using necessary boundary conditions. The various static characteristics have been presented to analyze the performance of bearing at zero speed.

  3. Static Characteristics of Conical Hydrostatic Journal Bearing Under Micropolar Lubrication

    NASA Astrophysics Data System (ADS)

    Rana, N. K.; Gautam, S. S.; Verma, S.

    2014-10-01

    A theoretical analysis for static characteristics of a conical hydrostatic journal bearing for a multirecess constant flow valve compensated under micropolar lubrication has been carried out in this work. The numerical solution of the modified Reynolds equation for the conical bearing has been done using Finite Element Method (FEM) using necessary boundary conditions. The various static characteristics have been presented to analyze the performance of bearing at zero speed.

  4. Static heterogeneities in liquid water

    NASA Astrophysics Data System (ADS)

    Stanley, H. Eugene; Buldyrev, Sergey V.; Giovambattista, Nicolas

    2004-10-01

    The thermodynamic behavior of water seems to be closely related to static heterogeneities. These static heterogeneities are related to the local structure of water molecules, and when properly characterized, may offer an economical explanation of thermodynamic data. The key feature of liquid water is not so much that the existence of hydrogen bonds, first pointed out by Linus Pauling, but rather the local geometry of the liquid molecules is not spherical or oblong but tetrahedral. In the consideration of static heterogeneities, this local geometry is critical. Recent experiments suggested more than one phase of amorphous solid water, while simulations suggest that one of these phases is metastable with respect to another, so that in fact there are only two stable phases.

  5. Utility Static Generation Reliability

    Energy Science and Technology Software Center (ESTSC)

    1993-03-05

    PICES (Probabilistic Investigation of Capacity and Energy Shortages) was developed for estimating an electric utility''s expected frequency and duration of capacity deficiencies on a daily on and off-peak basis. In addition to the system loss-of-load probability (LOLP) and loss-of-load expectation (LOLE) indices, PICES calculates the expected frequency and duration of system capacity deficiencies and the probability, expectation, and expected frequency and duration of a range of system reserve margin states. Results are aggregated and printedmore » on a weekly, monthly, or annual basis. The program employs hourly load data and either the two-state (on/off) or a more sophisticated three-state (on/partially on/fully off) generating unit representation. Unit maintenance schedules are determined on a weekly, levelized reserve margin basis. In addition to the 8760-hour annual load record, the user provides the following information for each unit: plant capacity, annual maintenance requirement, two or three-state unit failure and repair rates, and for three-state models, the partial state capacity deficiency. PICES can also supply default failure and repair rate values, based on the Edison Electric Institute''s 1979 Report on Equipment Availability for the Ten-Year Period 1968 Through 1977, for many common plant types. Multi-year analysis can be performed by specifying as input data the annual peak load growth rates and plant addition and retirement schedules for each year in the study.« less

  6. Quasi-Static Hydrodynamic Limits

    NASA Astrophysics Data System (ADS)

    De Masi, Anna; Olla, Stefano

    2015-12-01

    We consider hydrodynamic limits of interacting particles systems with open boundaries, where the exterior parameters change in a time scale slower than the typical relaxation time scale. The limit deterministic profiles evolve quasi-statically. These limits define rigorously the thermodynamic quasi static transformations also for transitions between non-equilibrium stationary states. We study first the case of the symmetric simple exclusion, where duality can be used, and then we use relative entropy methods to extend to other models like zero range systems. Finally we consider a chain of anharmonic oscillators in contact with a thermal Langevin bath with a temperature gradient and a slowly varying tension applied to one end.

  7. Static Fourier transform infrared spectrometer.

    PubMed

    Schardt, Michael; Murr, Patrik J; Rauscher, Markus S; Tremmel, Anton J; Wiesent, Benjamin R; Koch, Alexander W

    2016-04-01

    Fourier transform spectroscopy has established itself as the standard method for spectral analysis of infrared light. Here we present a robust and compact novel static Fourier transform spectrometer design without any moving parts. The design is well suited for measurements in the infrared as it works with extended light sources independent of their size. The design is experimentally evaluated in the mid-infrared wavelength region between 7.2 μm and 16 μm. Due to its large etendue, its low internal light loss, and its static design it enables high speed spectral analysis in the mid-infrared. PMID:27137061

  8. Voltage Sensors Monitor Harmful Static

    NASA Technical Reports Server (NTRS)

    2009-01-01

    A tiny sensor, small enough to be worn on clothing, now monitors voltage changes near sensitive instruments after being created to alert Agency workers to dangerous static buildup near fuel operations and avionics. San Diego s Quasar Federal Systems received a Small Business Innovation Research (SBIR) contract from Kennedy Space Center to develop its remote voltage sensor (RVS), a dime-sized electrometer designed to measure triboelectric changes in the environment. One of the unique qualities of the RVS is that it can detect static at greater distances than previous devices, measuring voltage changes from a few centimeters to a few meters away, due to its much-improved sensitivity.

  9. Magnetic bearings for a high-performance optical disk buffer, volume 2

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The operating instructions for the magnetic bearings of a high-performance optical disk buffer are provided. Among the topics that are discussed are the following: front panel layout, turn-on procedure, shut-down procedure, and latch-up protection. Additionally, comprehensive engineering drawings are presented for the design.

  10. [Static disorders in hereditary ataxias].

    PubMed

    Badalian, L O; Lebedeva, N N; Sidorova, O P

    1987-01-01

    Static disorders elicited by the adequate methods of the assessment of equilibrium (stabilography) and gait (plantography) in hereditary ataxias have been analyzed. These techniques of examination make it possible to quantitatively estimate motor disorders, supplement clinical findings and provide an opportunity for objective evaluation of the efficacy of the conducted therapy. PMID:3115017

  11. FORTRAN Static Source Code Analyzer

    NASA Technical Reports Server (NTRS)

    Merwarth, P.

    1984-01-01

    FORTRAN Static Source Code Analyzer program, SAP (DEC VAX version), automatically gathers statistics on occurrences of statements and structures within FORTRAN program and provides reports of those statistics. Provisions made for weighting each statistic and provide an overall figure of complexity.

  12. FORTRAN Static Source Code Analyzer

    NASA Technical Reports Server (NTRS)

    Merwarth, P.

    1982-01-01

    FORTRAN Static Source Code Analyzer program (SAP) automatically gathers and reports statistics on occurrences of statements and structures within FORTRAN program. Provisions are made for weighting each statistic, providing user with overall figure of complexity. Statistics, as well as figures of complexity, are gathered on module-by-module basis. Overall summed statistics are accumulated for complete input source file.

  13. Compiler-assisted static checkpoint insertion

    NASA Technical Reports Server (NTRS)

    Long, Junsheng; Fuchs, W. K.; Abraham, Jacob A.

    1992-01-01

    This paper describes a compiler-assisted approach for static checkpoint insertion. Instead of fixing the checkpoint location before program execution, a compiler enhanced polling mechanism is utilized to maintain both the desired checkpoint intervals and reproducible checkpoint 1ocations. The technique has been implemented in a GNU CC compiler for Sun 3 and Sun 4 (Sparc) processors. Experiments demonstrate that the approach provides for stable checkpoint intervals and reproducible checkpoint placements with performance overhead comparable to a previously presented compiler assisted dynamic scheme (CATCH) utilizing the system clock.

  14. Static and dynamic responses of an ultrathin adaptive secondary mirror

    NASA Astrophysics Data System (ADS)

    del Vecchio, Ciro; Brusa, Guido; Gallieni, Daniele; Lloyd-Hart, Michael; Davison, Warren B.

    1999-09-01

    We present the results of a compete set of static and dynamic runs of the FEA model of the MMT adaptive secondary. The thin mirror is the most delicate component of the MMT adaptive secondary unit, as it provides the deformable optical surface able to correct the incoming wavefront. The static performances are evaluated as a function of the various load cases arising form gravitational loads and from the forces deriving from the magnetic interactions between actuators. In addition, computations were performed to assess the dynamic response to the high bandwidth, adaptive correcting force.s In both cases, the performances of the adaptive mirror design are able to accommodate the severe specifications.

  15. Space station static and dynamic analyses using parallel methods

    NASA Technical Reports Server (NTRS)

    Gupta, V.; Newell, J.; Storaasli, O.; Baddourah, M.; Bostic, S.

    1993-01-01

    Algorithms for high-performance parallel computers are applied to perform static analyses of large-scale Space Station finite-element models (FEMs). Several parallel-vector algorithms under development at NASA Langley are assessed. Sparse matrix solvers were found to be more efficient than banded symmetric or iterative solvers for the static analysis of large-scale applications. In addition, new sparse and 'out-of-core' solvers were found superior to substructure (superelement) techniques which require significant additional cost and time to perform static condensation during global FEM matrix generation as well as the subsequent recovery and expansion. A method to extend the fast parallel static solution techniques to reduce the computation time for dynamic analysis is also described. The resulting static and dynamic algorithms offer design economy for preliminary multidisciplinary design optimization and FEM validation against test modes. The algorithms are being optimized for parallel computers to solve one-million degrees-of-freedom (DOF) FEMs. The high-performance computers at NASA afforded effective software development, testing, efficient and accurate solution with timely system response and graphical interpretation of results rarely found in industry. Based on the author's experience, similar cooperation between industry and government should be encouraged for similar large-scale projects in the future.

  16. Static behaviour of induced seismicity

    NASA Astrophysics Data System (ADS)

    Mignan, A.

    2015-12-01

    The standard paradigm to describe seismicity induced by fluid injection is to apply nonlinear diffusion dynamics in a poroelastic medium. I show that the spatiotemporal behaviour and rate evolution of induced seismicity can, instead, be expressed by geometric operations on a static stress field produced by volume change at depth. I obtain laws similar in form to the ones derived from poroelasticity while requiring a lower description length. Although fluid flow is known to occur in the ground, it is not pertinent to the behaviour of induced seismicity. The proposed model is equivalent to the static stress model for tectonic foreshocks generated by the Non-Critical Precursory Accelerating Seismicity Theory. This study hence verifies the explanatory power of this theory outside of its original scope.

  17. Size Scaling of Static Friction

    NASA Astrophysics Data System (ADS)

    Braun, O. M.; Manini, Nicola; Tosatti, Erio

    2013-02-01

    Sliding friction across a thin soft lubricant film typically occurs by stick slip, the lubricant fully solidifying at stick, yielding and flowing at slip. The static friction force per unit area preceding slip is known from molecular dynamics (MD) simulations to decrease with increasing contact area. That makes the large-size fate of stick slip unclear and unknown; its possible vanishing is important as it would herald smooth sliding with a dramatic drop of kinetic friction at large size. Here we formulate a scaling law of the static friction force, which for a soft lubricant is predicted to decrease as fm+Δf/Aγ for increasing contact area A, with γ>0. Our main finding is that the value of fm, controlling the survival of stick slip at large size, can be evaluated by simulations of comparably small size. MD simulations of soft lubricant sliding are presented, which verify this theory.

  18. Water cooled static pressure probe

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas T. (Inventor); Eves, John W. (Inventor); Reece, Garland D. (Inventor); Geissinger, Steve L. (Inventor)

    1991-01-01

    An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

  19. Static penetration resistance of soils

    NASA Technical Reports Server (NTRS)

    Durgunoglu, H. T.; Mitchell, J. K.

    1973-01-01

    Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests.

  20. Alkaline static feed electrolyzer based oxygen generation system

    NASA Technical Reports Server (NTRS)

    Noble, L. D.; Kovach, A. J.; Fortunato, F. A.; Schubert, F. H.; Grigger, D. J.

    1988-01-01

    In preparation for the future deployment of the Space Station, an R and D program was established to demonstrate integrated operation of an alkaline Water Electrolysis System and a fuel cell as an energy storage device. The program's scope was revised when the Space Station Control Board changed the energy storage baseline for the Space Station. The new scope was aimed at the development of an alkaline Static Feed Electrolyzer for use in an Environmental Control/Life Support System as an oxygen generation system. As a result, the program was divided into two phases. The phase 1 effort was directed at the development of the Static Feed Electrolyzer for application in a Regenerative Fuel Cell System. During this phase, the program emphasized incorporation of the Regenerative Fuel Cell System design requirements into the Static Feed Electrolyzer electrochemical module design and the mechanical components design. The mechanical components included a Pressure Control Assembly, a Water Supply Assembly and a Thermal Control Assembly. These designs were completed through manufacturing drawing during Phase 1. The Phase 2 effort was directed at advancing the Alkaline Static Feed Electrolyzer database for an oxygen generation system. This development was aimed at extending the Static Feed Electrolyzer database in areas which may be encountered from initial fabrication through transportation, storage, launch and eventual Space Station startup. During this Phase, the Program emphasized three major areas: materials evaluation, electrochemical module scaling and performance repeatability and Static Feed Electrolyzer operational definition and characterization.

  1. Three Inexpensive Static-Electricity Demonstrations.

    ERIC Educational Resources Information Center

    Gore, Gordon R.; Gregg, William R.

    1992-01-01

    Describes demonstrations to (1) construct an inexpensive static electricity detector; (2) obtain an abundant supply of either negative or positive charge using household items; and (3) create static electricity using a Tesla coil or Van de Graaff generator. (MDH)

  2. Vectoring Single Expansion Ramp Nozzle (VSERN) static model test program

    NASA Technical Reports Server (NTRS)

    Eames, D. J. H.; Mason, M. L.

    1988-01-01

    A variable throat-area, side-vectoring single expansion ramp nozzle (VSERN) concept's internal performance characteristics are studied with a view to controlling the bypass flow of an unmixed turbofan engine. Static tests have been conducted on VSERN at NASA-Langley using a variety of parametric models giving attention to the effects of upstream bend angle, ramp geometry, area ratio, and nozzle pressure ratio on static thrust and flow performance. Advantages of VSERN over the conventional vectoring axisymmetric convergent side-nozzles typified by those of the Harrier's Pegasus engine.

  3. Comparative Tests of Pitot-static Tubes

    NASA Technical Reports Server (NTRS)

    Merriam, Kenneth G; Spaulding, Ellis R

    1935-01-01

    Comparative tests were made on seven conventional Pitot-static tubes to determine their static, dynamic, and resultant errors. The effect of varying the dynamic opening, static opening, wall thickness, and inner-tube diameter was investigated. Pressure-distribution measurements showing stem and tip effects were also made. A tentative design for a standard Pitot-static tube for use in measuring air velocity is submitted.

  4. High-performance 0.25-um CMOS technology for fast SRAMs

    NASA Astrophysics Data System (ADS)

    Hayden, James D.; McNelly, T. F.; Perera, Asanga H.; Pfiester, Jim R.; Subramanian, C. K.; Thompson, Matthew A.

    1996-09-01

    A high performance 0.25 micrometers CMOS process has been developed for fast static RAMs. This technology features retrograde wells, shallow trench isolation scalable to a 0.45 micrometers active pitch, surface channel 0.25 micrometers NMOS and PMOS transistors with a 55 angstroms nitrided gate oxide providing drive currents of 630 and 300 (mu) A/micrometers respectively at off-leakages of 10 pA/micrometers , overgated TFTs with an on/off ratio greater than 6(DOT)105, stacked capacitors for improved SER protection, five levels of polysilicon planarized by chemical-mechanical polishing with two self-aligned interpoly contacts, 0.35 micrometers contacts and a 0.625 metal pitch. In this technology, a triple well structure was used for SER protection. High energy retrograde wells were integrated with shallow trench isolation and epi providing excellent interwell isolation for both leakage and latch-up down to n+/p+ spaces of 0.60 micrometers . PMOS transistors were scaled to a physical gate length of 0.1 micrometers while maintaining excellent short channel characteristics. A split word-line bitcell was scaled to 1.425 micrometers X 2.625 micrometers equals 3.74 micrometers 2 using 0.25 micrometers rules. A tungsten interpoly plug was used to connect the PMOS TFT loads to the underlying NMOS latch gates without a parasitic diode or dopant interdiffusion, connecting 3 polysilicon layers with self-aligned isolation from an intervening polysilicon layer used as a local interconnect. With this plug, TFT drive currents were greatly improved, particularly at low voltages and the memory nodes pulled to the fully supply voltage. Functional 0.25 micrometers bitcells were demonstrated and with an LDD resistor it was possible to double the cell stability. Bitcell simulation was used to demonstrate that a 4T bitcell will be stable at 2.5 V but that a word-line boost will be required for 1.8 V operation.

  5. 30 CFR 18.26 - Static electricity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static electricity. 18.26 Section 18.26 Mineral... § 18.26 Static electricity. Nonmetallic rotating parts, such as belts and fans, shall be provided with a means to prevent an accumulation of static electricity....

  6. 30 CFR 18.26 - Static electricity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static electricity. 18.26 Section 18.26 Mineral... § 18.26 Static electricity. Nonmetallic rotating parts, such as belts and fans, shall be provided with a means to prevent an accumulation of static electricity....

  7. 30 CFR 18.26 - Static electricity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static electricity. 18.26 Section 18.26 Mineral... § 18.26 Static electricity. Nonmetallic rotating parts, such as belts and fans, shall be provided with a means to prevent an accumulation of static electricity....

  8. 30 CFR 18.26 - Static electricity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static electricity. 18.26 Section 18.26 Mineral... § 18.26 Static electricity. Nonmetallic rotating parts, such as belts and fans, shall be provided with a means to prevent an accumulation of static electricity....

  9. 30 CFR 18.26 - Static electricity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static electricity. 18.26 Section 18.26 Mineral... § 18.26 Static electricity. Nonmetallic rotating parts, such as belts and fans, shall be provided with a means to prevent an accumulation of static electricity....

  10. 14 CFR 31.61 - Static discharge.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static discharge. 31.61 Section 31.61... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.61 Static discharge. Unless shown not to be... gas as a lifting means to ensure that the effects of static discharges will not create a hazard....

  11. 14 CFR 31.61 - Static discharge.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static discharge. 31.61 Section 31.61... STANDARDS: MANNED FREE BALLOONS Design Construction § 31.61 Static discharge. Unless shown not to be... gas as a lifting means to ensure that the effects of static discharges will not create a hazard....

  12. In-Flight Pitot-Static Calibration

    NASA Technical Reports Server (NTRS)

    Foster, John V. (Inventor); Cunningham, Kevin (Inventor)

    2016-01-01

    A GPS-based pitot-static calibration system uses global output-error optimization. High data rate measurements of static and total pressure, ambient air conditions, and GPS-based ground speed measurements are used to compute pitot-static pressure errors over a range of airspeed. System identification methods rapidly compute optimal pressure error models with defined confidence intervals.

  13. Static balancing of planar articulated robots

    NASA Astrophysics Data System (ADS)

    Quaglia, Giuseppe; Yin, Zhe

    2015-12-01

    Static balancing for a manipulator's weight is necessary in terms of energy saving and performance improvement. This paper proposes a method to design balancing devices for articulated robots in industry, based on robotic dynamics. Full design details for the balancing system using springs are presented from two aspects: One is the optimization for the position of the balancing system; the other is the design of the spring parameters. As examples, two feasible balancing devices are proposed, based on different robotic structures: The first solution consists of linkages and springs; the other consists of pulleys, cross mechanisms and (hydro-) pneumatic springs. Then the two solutions are compared. Pneumatic, hydro-pneumatic and mechanical springs are discussed and their parameters are decided according to the requirements of torque compensation. Numerical results show that with the proper design using the methodology presented in this paper, an articulated robot can be statically balanced perfectly in all configurations. This paper therefore provides a design method of the balancing system for other similar structures.

  14. Static current profile control and RFP confinement

    NASA Astrophysics Data System (ADS)

    Scheffel, Jan; Schnack, Dalton D.; Mirza, Ahmed A.

    2013-11-01

    Static current profile control (CPC) is shown numerically to substantially enhance plasma confinement in the reversed-field pinch (RFP). By suitable application of an auxiliary electric field and adjustment of its internal location, width and amplitude, strongly decreased levels of dynamo fluctuations are obtained. The simulations are performed using a fully non-linear, resistive magnetohydrodynamic model, including the effects of ohmic heating as well as parallel and perpendicular heat conduction along stochastic field lines. The importance of controlling the parallel current profile in the core plasma to minimize the effects of tearing modes on confinement is thus confirmed. A near three-fold increase in energy confinement is found and poloidal plasma beta increases by 30% from 0.20 to 0.27. The edge heat flux is reduced to a third of that of the conventional RFP. The high-confinement phase is interrupted here by a crash, characterized by a rapid decrease in confinement. A detailed study of the crash phase is carried out by the standard Δ‧ theory and a fully resistive linearized time-spectral method; the generalized weighted residual method. The analysis suggests that the instability is caused by pressure-driven, resistive g-modes. Inclusion of anisotropic thermal conduction reduces the linear growth rates. As compared with our earlier numerical studies of CPC in the RFP, employing feedback control, the present static control scheme should be more easily implemented experimentally.

  15. Static feed water electrolysis module

    NASA Technical Reports Server (NTRS)

    Powell, J. D.; Schubert, F. H.; Jensen, F. C.

    1974-01-01

    An advanced static feed water electrolysis module (SFWEM) and associated instrumentation for generating breathable O2 was developed. The system also generates a H2 byproduct for use in an air revitalization system for O2 recovery from metabolic CO2. Special attention was given to: (1) eliminating water feed compartment degassing, (2) eliminating need for zero gravity condenser/separators, (3) increasing current density capability, and (4) providing a self contained module so that operation is independent of laboratory instrumentation and complicated startup/shutdown procedures.

  16. Measurement of static pressure on aircraft

    NASA Technical Reports Server (NTRS)

    Gracey, William

    1958-01-01

    Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented. Errors due to the position of a static-pressure tube in the flow field of the airplane are given for locations ahead of the fuselage nose, ahead of the wing tip, and ahead of the vertical tail fin. The errors of static-pressure vents on the fuselage of an airplane are also presented. Various methods of calibrating static-pressure installations in flight are briefly discussed.

  17. First arrival time surface, estimation of statics

    SciTech Connect

    Chun, J.H.; Jacewitz, C.A.

    1983-09-05

    The problem of obtaining surface consistent statics using first arrival refractions has several phases. To begin with, the first arrivals must be picked in some reasonable, consistent fashion. Next, appropriate techniques must be used to solve for surface-consistent statics. Finally, the interpreter must be provided with an evaluation of the quality of the estimated statics. First arrival refractions are part of reflection seismic data. Early seismic reflection work used first arrival refractions for weathering static corrections. With the advent of the common midpoint (CMP) method, first arrivals lost their predominance in statics to correlation techniques within CMP gathers. However, the increasing use of a large number of receivers and a small group interval has made first arrival statics more reliable. In addition, recent work has helped to revitalize interest in the use of first arrival refractions for surface-consistent static corrections.

  18. Static behaviour of induced seismicity

    NASA Astrophysics Data System (ADS)

    Mignan, Arnaud

    2016-04-01

    The standard paradigm to describe seismicity induced by fluid injection is to apply non-linear diffusion dynamics in a poroelastic medium. I show that the spatio-temporal behaviour and rate evolution of induced seismicity can, instead, be expressed by geometric operations on a static stress field produced by volume change at depth. I obtain laws similar in form to the ones derived from poroelasticity while requiring a lower description length. Although fluid flow is known to occur in the ground, it is not pertinent to the geometrical description of the spatio-temporal patterns of induced seismicity. The proposed model is equivalent to the static stress model for tectonic foreshocks generated by the Non-Critical Precursory Accelerating Seismicity Theory. This study hence verifies the explanatory power of this theory outside of its original scope and provides an alternative physical approach to poroelasticity for the modelling of induced seismicity. The applicability of the proposed geometrical approach is illustrated for the case of the 2006, Basel enhanced geothermal system stimulation experiment. Applicability to more problematic cases where the stress field may be spatially heterogeneous is also discussed.

  19. Electrowetting -- from statics to dynamics.

    PubMed

    Chen, Longquan; Bonaccurso, Elmar

    2014-08-01

    More than one century ago, Lippmann found that capillary forces can be effectively controlled by external electrostatic forces. As a simple example, by applying a voltage between a conducting liquid droplet and the surface it is sitting on we are able to adjust the wetting angle of the drop. Since Lippmann's findings, electrocapillary phenomena - or electrowetting - have developed into a series of tools for manipulating microdroplets on solid surfaces, or small amounts of liquids in capillaries for microfluidic applications. In this article, we briefly review some recent progress of fundamental understanding of electrowetting and address some still unsolved issues. Specifically, we focus on static and dynamic electrowetting. In static electrowetting, we discuss some basic phenomena found in DC and AC electrowetting, and some theories about the origin of contact angle saturation. In dynamic electrowetting, we introduce some studies about this rather recent area. At last, we address some other capillary phenomena governed by electrostatics and we give an outlook that might stimulate further investigations on electrowetting. PMID:24268972

  20. Static-field-induced states

    NASA Astrophysics Data System (ADS)

    Gets, Artem V.; Tolstikhin, Oleg I.

    2013-01-01

    Considering an electron interacting with an atomic or molecular potential and an external static electric field, one usually focuses on narrow resonances at negative energies originating from the bound states in the absence of the field; we call them tunneling states (TSs). Meanwhile, there also exist relatively broad resonances at positive energies having no counterparts in the absence of the field; we call them static-field-induced states (SFISs). In this paper, the recently developed weak-field asymptotic theory of TSs [O. I. Tolstikhin , Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.84.053423 84, 053423 (2011)] is extended to SFISs. An asymptotic quantization condition defining the energies of SFISs in an arbitrary potential in the three-dimensional case is derived. The parabolic scattering amplitudes appearing in this quantization condition are defined. The theory is illustrated by calculations for the zero-range and Coulomb potentials. The SFISs in these potentials are found and their energies are shown to be in good agreement with the asymptotic results over a wide interval of the values of the field.

  1. Matching Voice and Face Identity from Static Images

    ERIC Educational Resources Information Center

    Mavica, Lauren W.; Barenholtz, Elan

    2013-01-01

    Previous research has suggested that people are unable to correctly choose which unfamiliar voice and static image of a face belong to the same person. Here, we present evidence that people can perform this task with greater than chance accuracy. In Experiment 1, participants saw photographs of two, same-gender models, while simultaneously…

  2. 40 CFR 53.64 - Test procedure: Static fractionator test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Test procedure: Static fractionator test. 53.64 Section 53.64 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Testing Performance Characteristics of Class II...

  3. 40 CFR 53.64 - Test procedure: Static fractionator test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Test procedure: Static fractionator test. 53.64 Section 53.64 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Testing Performance Characteristics of Class II...

  4. Static analysis of a piping system with elbows

    SciTech Connect

    Bryan, B.J.

    1994-03-01

    Vibration tests of elbows to failure were performed in Japan in the early 1970s. The piping system included two elbows and an eccentric mass. Tests were run both pressurized and unpressurized. This report documents a static analysis of the piping system in which the elbows are subjected to out of plane bending. The effects of internal pressure and material plasticity are investigated.

  5. Mass properties measurement system: Dynamics and statics measurements

    NASA Technical Reports Server (NTRS)

    Doty, Keith L.

    1993-01-01

    This report presents and interprets experimental data obtained from the Mass Properties Measurement System (MPMS). Statics measurements yield the center-of-gravity of an unknown mass and dynamics measurements yield its inertia matrix. Observations of the MPMS performance has lead us to specific design criteria and an understanding of MPMS limitations.

  6. Static properties of hydrostatic thrust gas bearings with curved surfaces.

    NASA Technical Reports Server (NTRS)

    Rehsteiner, F. H.; Cannon, R. H., Jr.

    1971-01-01

    The classical treatment of circular, hydrostatic, orifice-regulated thrust gas bearings, in which perfectly plane bearing plates are assumed, is extended to include axisymmetric, but otherwise arbitrary, plate profiles. Plate curvature has a strong influence on bearing load capability, static stiffness, tilting stiffness, and side force per unit misalignment angle. By a suitable combination of gas inlet impedance and concave plate profile, the static stiffness can be made almost constant over a wide load range, and to remain positive at the closure load. Extensive measurements performed with convex and concave plates agree with theory to within the experimental error throughout and demonstrate the practical feasibility of using curved plates.

  7. Demonstration of relaxed static stability on a commercial transport

    NASA Technical Reports Server (NTRS)

    Rising, J. J.; Davis, W. J.; Willey, C. S.

    1985-01-01

    The application of relaxed static stability was studied under a program to determine ways of improving the energy efficiency in current and future transport aircraft. Pitch active control systems (PACs) were developed for application in the near term to current aircraft and in the next generation to advanced aircrft of the future. Analyses identified potential drag benefits of: (1) 2% for current transport aircraft with neutral stability; and (2) as much as 17% for next generation aircraft with high aspect ratio supercritical wings which must operate 10 to 15% statistically unstable to achieve optimum performance. Flight test evaluations of the near-term PACs were conducted to a 3% mean aerodynamic chord (MAC) negative static margin on a Lockheed L-1011 aircraft. The advanced PACs was demonstrated to a 20% MAC negative static margin on a piloted visual motion simulator at the NASA Langley Research Center. Test results for both systems showed flying qualities characteristics as good as current conventional aircraft.

  8. Evaluation of flawed composite structure under static and cyclic loading

    NASA Technical Reports Server (NTRS)

    Porter, T. R.

    1977-01-01

    This paper presents the results of a program investigating the effects of initial defects on the fatigue and fracture response of composite laminates. The structural laminates investigated were a typical angle-ply laminate, a polar/hoop-wound pressure vessel laminate, and a typical engine fan blade laminate. Defects investigated were full- and half-penetration circular holes, full- and half-penetration slits, and countersink holes. Results are presented showing the effects of the defect size and type on the static fracture strength, fatigue performance, and residual static strength. The results of inspection procedures are shown, describing the effect of cyclic and static loadings on damage propagation in composite laminates. The data in this study were used to define proof test levels as a qualification procedure in composite structure subjected to cyclic loading.

  9. Static Response of Neutron Matter.

    PubMed

    Buraczynski, Mateusz; Gezerlis, Alexandros

    2016-04-15

    We generalize the problem of strongly interacting neutron matter by adding a periodic external modulation. This allows us to study from first principles a neutron system that is extended and inhomogeneous, with connections to the physics of both neutron-star crusts and neutron-rich nuclei. We carry out fully nonperturbative microscopic quantum Monte Carlo calculations of the energy of neutron matter at different densities, as well as different strengths and periodicities of the external potential. In order to remove systematic errors, we examine finite-size effects and the impact of the wave function ansatz. We also make contact with energy-density functional theories of nuclei and disentangle isovector gradient contributions from bulk properties. Finally, we calculate the static density-density linear response function of neutron matter and compare it with the response of other physical systems. PMID:27127963

  10. Static Response of Neutron Matter

    NASA Astrophysics Data System (ADS)

    Buraczynski, Mateusz; Gezerlis, Alexandros

    2016-04-01

    We generalize the problem of strongly interacting neutron matter by adding a periodic external modulation. This allows us to study from first principles a neutron system that is extended and inhomogeneous, with connections to the physics of both neutron-star crusts and neutron-rich nuclei. We carry out fully nonperturbative microscopic quantum Monte Carlo calculations of the energy of neutron matter at different densities, as well as different strengths and periodicities of the external potential. In order to remove systematic errors, we examine finite-size effects and the impact of the wave function ansatz. We also make contact with energy-density functional theories of nuclei and disentangle isovector gradient contributions from bulk properties. Finally, we calculate the static density-density linear response function of neutron matter and compare it with the response of other physical systems.

  11. Static mixer improves desalting efficiency

    SciTech Connect

    Not Available

    1983-10-01

    An in-line static mixer has increased salt removal from crude oil at a large West Coast refinery, says the mixer supplier, Komax Systems Inc. The mixer was installed at a 150,000 b/d crude distillation unit's desalter. Crude at this refinery is a mixture of local production and imports from Indonesia and Alaska. In the past, the refiner used a typical globe-type mix valve to mix fresh water with crude at the desalters. The crude is heated to 300/sup 0/F., mixed with 5% fresh water, and then fed to the desalters. Chemical and electrostatic treatment is used in the desalters to remove salt and water from the crude.

  12. Ares I Static Tests Design

    NASA Technical Reports Server (NTRS)

    Carson, William; Lindemuth, Kathleen; Mich, John; White, K. Preston; Parker, Peter A.

    2009-01-01

    Probabilistic engineering design enhances safety and reduces costs by incorporating risk assessment directly into the design process. In this paper, we assess the format of the quantitative metrics for the vehicle which will replace the Space Shuttle, the Ares I rocket. Specifically, we address the metrics for in-flight measurement error in the vector position of the motor nozzle, dictated by limits on guidance, navigation, and control systems. Analyses include the propagation of error from measured to derived parameters, the time-series of dwell points for the duty cycle during static tests, and commanded versus achieved yaw angle during tests. Based on these analyses, we recommend a probabilistic template for specifying the maximum error in angular displacement and radial offset for the nozzle-position vector. Criteria for evaluating individual tests and risky decisions also are developed.

  13. Residual Static Strength of ALuminum-Alloy Beams Containing Fatigue Cracks in the Tension Covers

    NASA Technical Reports Server (NTRS)

    Leybold, Herbert A.

    1961-01-01

    Static tests were performed on 31 box beams containing fatigue cracks in order to determine their residual static strengths. The beams were constructed of 7075 and 2024 aluminum alloy according to several designs and employed stringers that were either bonded, riveted, or an integral part of the skin. skin (both aaterials) had the highest residual static strengths, whereas 7075 beams with integrally stiffened covers had the lowest residual static strengths. Except for the integrally stiffened beams, the skin material did not contribute to the residual static strength of the beams because the crack propagated across the skin before maximum load was reached. For the integrally stiffened beams, crack propagation and failure were synonymous. The test results are compared with predictions of the residual static strength. Fair agreement between predicted strength and actual strength was obtained for all beams tested.

  14. Trend of tunnel magnetoresistance and variation in threshold voltage for keeping data load robustness of metal–oxide–semiconductor/magnetic tunnel junction hybrid latches

    SciTech Connect

    Ohsawa, T.; Ikeda, S.; Hanyu, T.; Ohno, H.; Endoh, T.

    2014-05-07

    The robustness of data load of metal–oxide–semiconductor/magnetic tunnel junction (MOS/MTJ) hybrid latches at power-on is examined by using Monte Carlo simulation with the variations in magnetoresistances for MTJs and in threshold voltages for MOSFETs involved in 90 nm technology node. Three differential pair type spin-transfer-torque-magnetic random access memory cells (4T2MTJ, 6T2MTJ, and 8T2MTJ) are compared for their successful data load at power-on. It is found that the 4T2MTJ cell has the largest pass area in the shmoo plot in TMR ratio (tunnel magnetoresistance ratio) and V{sub dd} in which a whole 256 kb cell array can be powered-on successfully. The minimum TMR ratio for the 4T2MTJ in 0.9 V < V{sub dd} < 1.9 V is 140%, while the 6T2MTJ and the 8T2MTJ cells require TMR ratio larger than 170%.

  15. The Influence of Visual Cognitive Style when Learning from Instructional Animations and Static Pictures

    ERIC Educational Resources Information Center

    Hoffler, Tim N.; Prechtl, Helmut; Nerdel, Claudia

    2010-01-01

    In a 2 x 2 design, we examined the role of visual cognitive style in two multimedia-based learning environments (text plus static pictures/animations). A statistically significant interaction was obtained for deeper comprehension: Highly developed visualizers (HDV) who learned with static pictures performed better than HDV who learned with…

  16. Uranium transformations in static microcosms.

    SciTech Connect

    Kelly, S. D.; Wu, W.; Yang, F.; Criddle, C.; Marsh, T. L.; O'Loughlin, E. J.; Ravel, B.; Watson, D.; Jardine, P. M.; Kemner, K. M.; Stanford Univ.; Michigan State Univ.; ORNL; BNL; EXAFS Analysis

    2010-01-01

    Elucidation of complex biogeochemical processes and their effects on speciation of U in the subsurface is critical for developing remediation strategies with an understanding of stability. We have developed static microcosms that are similar to bioreduction process studies in situ under laminar flow conditions or in sediment pores. Uranium L{sub 3}-edge X-ray absorption near-edge spectroscopy analysis with depth in the microcosms indicated that transformation of U{sup VI} to U{sup IV} occurred by at least two distinct processes. Extended X-ray absorption fine structure (EXAFS) analysis indicated that initial U{sup VI} species associated with C- and P-containing ligands were transformed to U{sup IV} in the form of uraninite and U associated with Fe-bound ligands. Microbial community analysis identified putative Fe{sup III} and sulfate reducers at two different depths in the microcosms. The slow reduction of U{sup VI} to U{sup IV} may contribute the stability of U{sup IV} within microcosms at 11 months after a decrease in bioreducing conditions due to limited electron donors.

  17. Studies on proper simulation during static testing of forward speed effects on fan noise

    NASA Technical Reports Server (NTRS)

    Peracchio, A. A.; Ganz, U. W.; Gedge, M. R.; Robbins, K.

    1980-01-01

    Significant differences exist in the noise generated by engines in flight and engines operating on the test stand. It was observed that these differences can be reduced by the use of an inflow control structure (ICS) in the static test configuration. The results of the third phase of a three phase program are described. The work performed in the first two phases which dealt with the development of a model for atmospheric turbulence, studies of fan noise generated by rotor turbulence interaction, and the development of an inflow control structure design system are summarized. The final phase of the program covers procedures for performing static testing with an ICS projecting the resulting static test data to actual flight test data. Included is a procedures report which covers the design system and techniques for static testing and projecting the static data to flight.

  18. The Neglect of Monotone Comparative Statics Methods

    ERIC Educational Resources Information Center

    Tremblay, Carol Horton; Tremblay, Victor J.

    2010-01-01

    Monotone methods enable comparative static analysis without the restrictive assumptions of the implicit-function theorem. Ease of use and flexibility in solving comparative static and game-theory problems have made monotone methods popular in the economics literature and in graduate courses, but they are still absent from undergraduate…

  19. Static Material Strength Determined Using a DAC

    SciTech Connect

    Cynn, H; Evans, W; Klepeis, J P; Lipp, M; Liermann, P; Yang, W

    2009-06-04

    By measuring sample thickness and pressure gradient using x-ray absorption and x-ray diffraction, respectively, the accurate static yield strengths of Ta and Fe were determined at high pressure. This improved method has several advantages over other similar methods to quantitatively determine static material strength.

  20. Comparing Techniques for Certified Static Analysis

    NASA Technical Reports Server (NTRS)

    Cachera, David; Pichardie, David

    2009-01-01

    A certified static analysis is an analysis whose semantic validity has been formally proved correct with a proof assistant. The recent increasing interest in using proof assistants for mechanizing programming language metatheory has given rise to several approaches for certification of static analysis. We propose a panorama of these techniques and compare their respective strengths and weaknesses.

  1. 49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Static Noise Test Protocols-In-Cab Static H Appendix H to Part 229 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Pt. 229, App. H Appendix H to Part 229—Static Noise...

  2. Remote histology learning from static versus dynamic microscopic images.

    PubMed

    Mione, Sylvia; Valcke, Martin; Cornelissen, Maria

    2016-05-01

    Histology is the study of microscopic structures in normal tissue sections. Curriculum redesign in medicine has led to a decrease in the use of optical microscopes during practical classes. Other imaging solutions have been implemented to facilitate remote learning. With advancements in imaging technologies, learning material can now be digitized. Digitized microscopy images can be presented in either a static or dynamic format. This study of remote histology education identifies whether dynamic pictures are superior to static images for the acquisition of histological knowledge. Test results of two cohorts of second-year Bachelor in Medicine students at Ghent University were analyzed in two consecutive academic years: Cohort 1 (n = 190) and Cohort 2 (n = 174). Students in Cohort 1 worked with static images whereas students in Cohort 2 were presented with dynamic images. ANCOVA was applied to study differences in microscopy performance scores between the two cohorts, taking into account any possible initial differences in prior knowledge. The results show that practical histology scores are significantly higher with dynamic images as compared to static images (F (1,361) = 15.14, P < 0.01), regardless of student's gender and performance level. Several reasons for this finding can be explained in accordance with cognitivist learning theory. Since the findings suggest that knowledge construction with dynamic pictures is stronger as compared to static images, dynamic images should be introduced in a remote setting for microscopy education. Further implementation within a larger electronic learning management system needs to be explored in future research. Anat Sci Educ 9: 222-230. © 2015 American Association of Anatomists. PMID:26441000

  3. Static and Dynamic Moduli of Malm Carbonate: A Poroelastic Correlation

    NASA Astrophysics Data System (ADS)

    Hassanzadegan, Alireza; Guérizec, Romain; Reinsch, Thomas; Blöcher, Guido; Zimmermann, Günter; Milsch, Harald

    2016-06-01

    The static and poroelastic moduli of a porous rock, e.g., the drained bulk modulus, can be derived from stress-strain curves in rock mechanical tests, and the dynamic moduli, e.g., dynamic Poisson's ratio, can be determined by acoustic velocity and bulk density measurements. As static and dynamic elastic moduli are different, a correlation is often required to populate geomechanical models. A novel poroelastic approach is introduced to correlate static and dynamic bulk moduli of outcrop analogues samples, representative of Upper-Malm reservoir rock in the Molasse basin, southwestern Germany. Drained and unjacketed poroelastic experiments were performed at two different temperature levels (30 and 60°). For correlating the static and dynamic elastic moduli, a drained acoustic velocity ratio is introduced, corresponding to the drained Poisson's ratio in poroelasticity. The strength of poroelastic coupling, i.e., the product of Biot and Skempton coefficients here, was the key parameter. The value of this parameter decreased with increasing effective pressure by about 56 ~% from 0.51 at 3 MPa to 0.22 at 73 MPa. In contrast, the maximum change in P- and S-wave velocities was only 3 % in this pressure range. This correlation approach can be used in characterizing underground reservoirs, and can be employed to relate seismicity and geomechanics (seismo-mechanics).

  4. Static aeroelastic analysis of a three-dimensional generic wing

    NASA Technical Reports Server (NTRS)

    Green, John A.; Lee, IN; Miura, Hirokazu

    1990-01-01

    A continuation of research on the static aeroelastic analysis of a generic wing configuration is presented. Results of the study of the asymmetric oblique wing model developed by Rockwell International, in conjunction with the NASA Oblique Wing Research Aircraft Program, are reported. The capability to perform static aeroelastic analyses of an oblique wing at arbitrary skew positions is demonstrated by applying the MSC/NASTRAN static analysis scheme modified by the aerodynamic influence coefficient matrix created by the NASA Ames aerodynamic panel codes. The oblique wing is studied at two skew angles, and in particular, the capability to calculate 3-D thickness effects on the aerodynamic properties of the wing is investigated. The ability to model asymmetric wings in both subsonic and supersonic Mach numbers is shown. The aerodynamic influence coefficient matrix computed by the external programs is inserted in MSC/NASTRAN static aeroelasticity analysis run stream to compute the aeroelastic deformation and internal forces. Various aerodynamic coefficients of the oblique wing were computed for two Mach numbers, 0.7 and 1.4, and the angle of attach -5 through 15 deg.

  5. Static aeroelastic analysis of a three-dimensional oblique wing

    NASA Technical Reports Server (NTRS)

    Lee, I.; Miura, H.; Chargin, M. K.

    1990-01-01

    A capability to perform static aeroelastic analyses of an oblique wing at arbitrary skew positions was developed based on the framework of the MSC/NASTRAN static aeroelastic analysis. By means of DMAP alterations, a portion of the subsonic static aeroelastic analysis scheme was modified to insert an aerodynamic influence coefficient matrix created externally by the NASA-Ames aerodynamic panel codes. The modified scheme can cover the subsonic as well as the supersonic range for both symmetric and asymmetric configurations. Static aeroelastic responses of the oblique wing are studied at two skew angles and, in particular, the capability to calculate 3D camber effects on the aerodynamic properties of the wing is investigated. Various aerodynamic coefficients of the rigid oblique wing are computed for two Mach numbers, 0.7 and 1.4, and the angle of attack is varied from -5 through 15 deg. Also, the wing flexibility effects on the aerodynamic coefficients and the displacement are examined at a Mach number of 0.7 for a 45-deg swept wing.

  6. Static and Dynamic Moduli of Malm Carbonate: A Poroelastic Correlation

    NASA Astrophysics Data System (ADS)

    Hassanzadegan, Alireza; Guérizec, Romain; Reinsch, Thomas; Blöcher, Guido; Zimmermann, Günter; Milsch, Harald

    2016-08-01

    The static and poroelastic moduli of a porous rock, e.g., the drained bulk modulus, can be derived from stress-strain curves in rock mechanical tests, and the dynamic moduli, e.g., dynamic Poisson's ratio, can be determined by acoustic velocity and bulk density measurements. As static and dynamic elastic moduli are different, a correlation is often required to populate geomechanical models. A novel poroelastic approach is introduced to correlate static and dynamic bulk moduli of outcrop analogues samples, representative of Upper-Malm reservoir rock in the Molasse basin, southwestern Germany. Drained and unjacketed poroelastic experiments were performed at two different temperature levels (30 and 60°C). For correlating the static and dynamic elastic moduli, a drained acoustic velocity ratio is introduced, corresponding to the drained Poisson's ratio in poroelasticity. The strength of poroelastic coupling, i.e., the product of Biot and Skempton coefficients here, was the key parameter. The value of this parameter decreased with increasing effective pressure by about 56 ~% from 0.51 at 3 MPa to 0.22 at 73 MPa. In contrast, the maximum change in P- and S-wave velocities was only 3 % in this pressure range. This correlation approach can be used in characterizing underground reservoirs, and can be employed to relate seismicity and geomechanics (seismo-mechanics).

  7. Interpretational conflicts between the static and non-static forms of the de Sitter metric.

    PubMed

    Mitra, Abhas

    2012-01-01

    The de-Sitter metric is a special form of the non-static Friedmann metric, and appears to be genuinely non-static since it describes the initial exponential expansion of the Big Bang universe. However, the de Sitter metric appears to be perfectly static in the Schwarzschild frame where the vacuum fluid is supposed to be in motion. Here we highlight the conflicts between the static and non-static versions of the de-Sitter metric from a physical perspective. In particular, while the "Principle of Energy Conservation" is honored in one case, the same is badly violated for the other. However, we offer a partial resolution of such conflicts by deriving the static de Sitter metric by solving the relevant field equations. It is seen that, it is the very special vacuum equation of state pressure = -density which results in the static form even when the vacuum fluid is supposed to be in motion. PMID:23213359

  8. Martian Atmospheric Pressure Static Charge Elimination Tool

    NASA Technical Reports Server (NTRS)

    Johansen, Michael R.

    2014-01-01

    A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

  9. Modeling of Long-Range Atmospheric Lasercom Links Between Static and Mobile Platforms

    SciTech Connect

    Scharlemann, E T; Breitfeller, E F; Henderson, J R; Kallman, J S; Morris, J R; Ruggiero, A J

    2003-07-29

    We describe modeling and simulation of long-range terrestrial laser communications links between static and mobile platforms. Atmospheric turbulence modeling, along with pointing, tracking and acquisition models are combined to provide an overall capability to estimate communications link performance.

  10. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the correlation between air pressure in the static pressure system and true ambient atmospheric static... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static pressure system. 23.1325 Section 23...: Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure...

  11. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the correlation between air pressure in the static pressure system and true ambient atmospheric static... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static pressure system. 23.1325 Section 23...: Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure...

  12. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the correlation between air pressure in the static pressure system and true ambient atmospheric static... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static pressure system. 23.1325 Section 23...: Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure...

  13. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the correlation between air pressure in the static pressure system and true ambient atmospheric static... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static pressure system. 23.1325 Section 23...: Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure...

  14. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the correlation between air pressure in the static pressure system and true ambient atmospheric static... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static pressure system. 23.1325 Section 23...: Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure...

  15. Static conversion systems. [for space power reactors

    NASA Technical Reports Server (NTRS)

    Ewell, R.; Mondt, J.

    1985-01-01

    Historically, all space power systems that have actually flown in space have relied on static energy conversion technology. Thus, static conversion is being considered for space nuclear power systems as well. There are four potential static conversion technologies which should be considered. These include: the alkali metal thermoelectric converter (AMTEC), the thermionic converter, the thermoelectric converter, and the thermophotovoltaic converter (TPV). These four conversion technologies will be described in brief detail along with their current status and development needs. In addition, the systems implications of using each of these conversion technologies with a space nuclear reactor power system will be evaluated and some comparisons made.

  16. Quasi-Static Viscoelasticity Loading Measurements of an Aircraft Tire

    NASA Technical Reports Server (NTRS)

    Mason, Angela J.; Tanner, John A.; Johnson, Arthur R.

    1997-01-01

    Stair-step loading, cyclic loading, and long-term relaxation tests were performed on an aircraft tire to observe the quasi-static viscoelastic response of the tire. The data indicate that the tire continues to respond viscoelastically even after it has been softened by deformation. Load relaxation data from the stair-step test at the 15,000-lb loading was fit to a monotonically decreasing Prony series.

  17. Delaminations in composite plates under transverse static loads - Experimental results

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; He, Yi-Fei; Springer, George S.

    1992-01-01

    Tests were performed measuring the damage initiation loads and the locations, shapes, and sizes of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static loads. The data were compared to the results of the Finn-Springer model, and good agreements were found between the measured and calculated delamination lengths and widths.

  18. Dynamic simulation of Static Var Compensators in distribution systems

    SciTech Connect

    Koessler, R.J. )

    1992-08-01

    This paper is a system study guide for the correction of voltage dips due to large motor startups with Static Var Compensators (SVCs). The method utilizes time simulations, which are an important aid in the equipment design and specification. The paper illustrates the process of setting-up a computer model and performing time simulations. The study process is demonstrated through an example, the Shawnee feeder in the Niagara Mohawk Power Corporation service area.

  19. Cooperation among Wirelessly Connected Static and Mobile Sensor Nodes for Surveillance Applications

    PubMed Central

    de Freitas, Edison Pignaton; Heimfarth, Tales; Vinel, Alexey; Wagner, Flávio Rech; Pereira, Carlos Eduardo; Larsson, Tony

    2013-01-01

    This paper presents a bio-inspired networking strategy to support the cooperation between static sensors on the ground and mobile sensors in the air to perform surveillance missions in large areas. The goal of the proposal is to provide low overhead in the communication among sensor nodes, while allocating the mobile sensors to perform sensing activities requested by the static ones. Simulations have shown that the strategy is efficient in maintaining low overhead and achieving the desired coordination. PMID:24072028

  20. Comparison of hemodynamic responses to static and dynamic exercise.

    PubMed

    Bezucha, G R; Lenser, M C; Hanson, P G; Nagle, F J

    1982-12-01

    Eight healthy male adults (25-34 yr) were studied to compare hemodynamic responses to static exercise (30% MVC in leg extension), static-dynamic exercise (one-arm cranking, 66 and 79% VO2 max-arm), and dynamic exercise (two-leg cycling, 58 and 82% VOmax-legs). Leg extension (LE) strength was measured by a spring scale. Cranking and cycling were performed on a Quinton bicycle ergometer. VO2 was measured using an automated open-circuit system. Heart rate (HR) was monitored from a CM-5 ECG lead, and arterial pressure (Pa) was measured from an indwelling brachial artery catheter. Cardiac output (Q) was measured using a CO2-rebreathing procedure. Total peripheral resistance (TPR) was calculated using the mean arterial pressure (Pa) as the systemic pressure gradient. In 30% LE, a significant (P less than 0.05) Pa increase occurred (pressor response) mediated primarily by an increase in Q. One-arm cranking and two-leg cycling at similar relative VO2 demands resulted in nearly identical increases in Pa due to different contributions of Q and TPR. Q and the arteriovenous O2 difference varied as a function of VO2 regardless of the mode of exercise (static or dynamic). On the other hand, the HR response, which accounted for increased Q in the exercises containing a static component, and Pa varied with mode of exercise. Any generalized scheme of cardiovascular control during exercise must account for the potential influence of dynamic and static components of the exercise. PMID:7153155

  1. Teaching Comparative Statics with Microsoft Excel.

    ERIC Educational Resources Information Center

    Barreto, Humberto

    2001-01-01

    Describes a Web site that makes use of the Comparative Statics Wizard add-in feature for Microsoft Excel. Enables students to focus on economic problems involving optimality, rate of change, and equilibrium solutions. (JEH)

  2. Static solutions for fourth order gravity

    SciTech Connect

    Nelson, William

    2010-11-15

    The Lichnerowicz and Israel theorems are extended to higher order theories of gravity. In particular it is shown that Schwarzschild is the unique spherically symmetric, static, asymptotically flat, black-hole solution, provided the spatial curvature is less than the quantum gravity scale outside the horizon. It is then shown that in the presence of matter (satisfying certain positivity requirements), the only static and asymptotically flat solutions of general relativity that are also solutions of higher order gravity are the vacuum solutions.

  3. Economics of static VAR compensation. Final report

    SciTech Connect

    Alvarado, F.L.; DeMarco, C.; Jung, T.H.

    1992-09-01

    This project was initiated in anticipation of widened use of static VAR (volt-ampere-reactive) compensation on US bulk-power transmission systems to increase levels of secure power transfer. Project objectives were to deten-nine power system cost savings and reliability benefits resulting from such use. System operating cost and stability probabilities were compared with and without static VAR compensation, applying simulation techniques. For the particular system model studied, there was a 21.4 percent reduction in operating costs taking into account losses added by the static VAR compensator. A procedure was developed to compare instability probabilities for various loadings and static VAR compensator sizes on a power system. For the particular system model studied, the static VAR compensator provided a significant increase in stability but over a narrow range of loading. Static VAR compensation is one of a number of promising FACTS (Flexible AC Transmission System) technologies for handling the demands of increased power transfers on power systems where transmission lines cannot be built or as a short-term altemative to building additional lines.

  4. Performance.

    PubMed

    Chambers, David W

    2006-01-01

    High performance is difficult to maintain because it is dynamic and not well understood. Based on a synthesis of many sources, a model is proposed where performance is a function of the balance between capacity and challenge. Too much challenge produces coping (or a crash); excess capacity results in boredom. Over time, peak performance drifts toward boredom. Performance can be managed by adjusting our level of ability, our effort, the opportunity to perform, and the challenge we agree to take on. Coping, substandard but acceptable performance, is common among professionals and its long-term side effects can be debilitating. A crash occurs when coping mechanisms fail. PMID:17020177

  5. Development of a static feed water electrolysis system

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Lantz, J. B.; Hallick, T. M.

    1982-01-01

    A one person level oxygen generation subsystem was developed and production of the one person oxygen metabolic requirements, 0.82 kg, per day was demonstrated without the need for condenser/separators or electrolyte pumps. During 650 hours of shakedown, design verification, and endurance testing, cell voltages averaged 1.62 V at 206 mA/sq cm and at average operating temperature as low as 326 K, virtually corresponding to the state of the art performance previously established for single cells. This high efficiency and low waste heat generation prevented maintenance of the 339 K design temperature without supplemental heating. Improved water electrolysis cell frames were designed, new injection molds were fabricated, and a series of frames was molded. A modified three fluid pressure controller was developed and a static feed water electrolysis that requires no electrolyte in the static feed compartment was developed and successfully evaluated.

  6. Gait recognition under carrying condition: a static dynamic fusion method

    NASA Astrophysics Data System (ADS)

    Yu, Guan; Li, Chang-Tsun; Hu, Yongjian

    2012-06-01

    When an individual carries an object, such as a briefcase, conventional gait recognition algorithms based on average silhouette/Gait Energy Image (GEI) do not always perform well as the object carried may have the potential of being mistakenly regarded as a part of the human body. To solve such a problem, in this paper, instead of directly applying GEI to represent the gait information, we propose a novel dynamic feature template for classification. Based on this extracted dynamic information and some static feature templates (i.e., head part and trunk part), we cast gait recognition on the large USF (University of South Florida) database by adopting a static/dynamic fusion strategy. For the experiments involving carrying condition covariate, significant improvements are achieved when compared with other classic algorithms.

  7. Matlab Stability and Control Toolbox: Trim and Static Stability Module

    NASA Technical Reports Server (NTRS)

    Crespo, Luis G.; Kenny, Sean P.

    2006-01-01

    This paper presents the technical background of the Trim and Static module of the Matlab Stability and Control Toolbox. This module performs a low-fidelity stability and control assessment of an aircraft model for a set of flight critical conditions. This is attained by determining if the control authority available for trim is sufficient and if the static stability characteristics are adequate. These conditions can be selected from a prescribed set or can be specified to meet particular requirements. The prescribed set of conditions includes horizontal flight, take-off rotation, landing flare, steady roll, steady turn and pull-up/ push-over flight, for which several operating conditions can be specified. A mathematical model was developed allowing for six-dimensional trim, adjustable inertial properties, asymmetric vehicle layouts, arbitrary number of engines, multi-axial thrust vectoring, engine(s)-out conditions, crosswind and gyroscopic effects.

  8. Anisotropic energy transfers in quasi-static magnetohydrodynamic turbulence

    SciTech Connect

    Reddy, K. Sandeep; Kumar, Raghwendra; Verma, Mahendra K.

    2014-10-15

    We perform direct numerical simulations of quasi-static magnetohydrodynamic turbulence and compute various energy transfers including the ring-to-ring and conical energy transfers, and the energy fluxes of the perpendicular and parallel components of the velocity field. We show that the rings with higher polar angles transfer energy to ones with lower polar angles. For large interaction parameters, the dominant energy transfer takes place near the equator (polar angle θ≈(π)/2 ). The energy transfers are local both in wavenumbers and angles. The energy flux of the perpendicular component is predominantly from higher to lower wavenumbers (inverse cascade of energy), while that of the parallel component is from lower to higher wavenumbers (forward cascade of energy). Our results are consistent with earlier results, which indicate quasi two-dimensionalization of quasi-static magnetohydrodynamic flows at high interaction parameters.

  9. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    PubMed Central

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  10. Some observations on loss of static strength due to fatigue cracks

    NASA Technical Reports Server (NTRS)

    Illg, Walter; Hardrath, Herbert F

    1955-01-01

    Static tensile tests were performed on simple notched specimens containing fatigue cracks. Four types of aluminum alloys were investigated: 2024-T3(formerly 24S-T3) and 7075-T6(formerly 75S-T6) in sheet form, and 2024-T4(formerly 24S-T4) and 7075-T6(formerly 75S-T6) in extruded form. The cracked specimens were tested statically under four conditions: unmodified and with reduced eccentricity of loading by three methods. Results of static tests on C-46 wings containing fatigue cracks are also reported.

  11. Methodology for determining elevon deflections to trim and maneuver the DAST vehicle with negative static margin

    NASA Technical Reports Server (NTRS)

    Perry, B., III

    1982-01-01

    The relationships between elevon deflection and static margin using elements from static and dynamic stability and control and from classical control theory are emphasized. Expressions are derived and presented for calculating elevon deflections required to trim the vehicle in lg straight-and-level flight and to perform specified longitudinal and lateral maneuvers. Applications of this methodology are made at several flight conditions for the ARW-2 wing. On the basis of these applications, it appears possible to trim and maneuver the vehicle with the existing elevons at -15% static margin.

  12. Static second-order polarizabilities of aminobenzophenones and nitrobenzophenones

    NASA Technical Reports Server (NTRS)

    Moore, Craig E.; Cardelino, Beatriz H.

    1991-01-01

    Static-field theoretical studies on molecular second-order polarizabilities (beta) of benzophenone derivatives were performed. Calculations were based on the use of shaped electric fields and semiempirical Hamiltonians. Either an electron-donating (amine) or an electron-withdrawing (nitro) substituent was incorporated into a phenyl ring of benzophenone; the phenyl rings of benzophenone were oriented either coplanar or perpendicular to the carbonyl. The change in charge transfer with respect to the electrophilic character of the carbonyl group was monitored to determine its effect on the molecular second-order polarizability. Calculations were performed for all constitutional isomers of the two benzophenone derivatives.

  13. Miniaturized double latching solenoid valve

    NASA Technical Reports Server (NTRS)

    Smith, James T. (Inventor)

    2010-01-01

    A valve includes a generally elongate pintle; a spacer having a rounded surface that bears against the pintle; a bulbous tip fixed to the spacer; and a hollow, generally cylindrical collar fixed to the pintle, the collar enclosing the spacer and the tip and including an opening through which a portion of the tip extends, the opening in the collar and interior of the collar being of a size such that the tip floats therein.

  14. Hydraulic latch scram release mechanism

    SciTech Connect

    Noyes, R. C.; Zaman, S. U.

    1980-02-05

    A poison bundle release mechanism within a safety assembly of a liquid metal nuclear reactor. A baffle consisting of a plate with recesses in fluid communication with low pressure coolant is formed in the upper portion of the safety assembly. A plug attached to the upper end of the poison bundle fits snugly against the recesses and is held up against the plate by the coolant pressure difference acting on the lower and upper sides of the plug. A conduit and valve arrangement is provided within the plug whereby the actuation of the valve permits high pressure coolant to enter the recessed region, reducing the pressure difference across the plug and producing rapid disengagement thereof from the plate.

  15. Visualization study on the static flow field around a straight-bladed vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Li, Yan; Tagawa, Kotaro

    2010-03-01

    Visual experiments based on the smoke wire way were carried out on a small model of Straight-blade Vertical Axis Wind Turbine (SB-VAWT) to invest the relationship between the static flow field characteristics and the rotor azimuth angle. The test rotor had 3 blades with NACA0018 aerofoil. The rotor diameter and blade chord were 0.3m and 0.07m, respectively. Visual photos of the static flow path lines in and around the rotor were obtained at every 5 degrees of the azimuth angle. Further, numerical computations of the static flow filed were also carried out for comparison with the same situation as the visual tests and the static torques at different azimuth angles were calculated. According to the results of visual tests and computations, the dependence of the starting performance on the azimuth angle was discussed. The solidity is an important factor affecting the starting performance of the SB-VAWT.

  16. Visualization study on the static flow field around a straight-bladed vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Li, Yan; Tagawa, Kotaro

    2009-12-01

    Visual experiments based on the smoke wire way were carried out on a small model of Straight-blade Vertical Axis Wind Turbine (SB-VAWT) to invest the relationship between the static flow field characteristics and the rotor azimuth angle. The test rotor had 3 blades with NACA0018 aerofoil. The rotor diameter and blade chord were 0.3m and 0.07m, respectively. Visual photos of the static flow path lines in and around the rotor were obtained at every 5 degrees of the azimuth angle. Further, numerical computations of the static flow filed were also carried out for comparison with the same situation as the visual tests and the static torques at different azimuth angles were calculated. According to the results of visual tests and computations, the dependence of the starting performance on the azimuth angle was discussed. The solidity is an important factor affecting the starting performance of the SB-VAWT.

  17. Acceleration of a Static Observer Near the Event Horizon of a Static Isolated Black Hole.

    ERIC Educational Resources Information Center

    Doughty, Noel A.

    1981-01-01

    Compares the magnitude of the proper acceleration of a static observer in a static, isolated, spherically symmetric space-time region with the Newtonian result including the situation in the interior of a perfect-fluid star. This provides a simple physical interpretation of surface gravity and illustrates the global nature of the event horizon.…

  18. 49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (Reaffirmed 2001) in this section in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain a copy... 49 Transportation 4 2011-10-01 2011-10-01 false Static Noise Test Protocols-In-Cab Static H Appendix H to Part 229 Transportation Other Regulations Relating to Transportation (Continued)...

  19. Control law development for a close-coupled canard, relaxed static stability fighter

    NASA Technical Reports Server (NTRS)

    Klein, R. W.; Lapins, M.; Martorella, R. P.; Sturm, M.

    1982-01-01

    The performance benefits to be gained from relaxed static stability (RSS) are illustrated for M = 0.9 and M = 2.0 flight conditions. The longitudinal, directional, and lateral control system structure is developed. The effect of static margin, bandwidth, and canard-wing interaction on canard rate requirements is analyzed. Control and maneuver limiter functions are developed and implemented about all three axes; simulation results strikingly demonstrate the concomitant improvement in energy management and improved resistance to departure and spin.

  20. Sawja: Static Analysis Workshop for Java

    NASA Astrophysics Data System (ADS)

    Hubert, Laurent; Barré, Nicolas; Besson, Frédéric; Demange, Delphine; Jensen, Thomas; Monfort, Vincent; Pichardie, David; Turpin, Tiphaine

    Static analysis is a powerful technique for automatic verification of programs but raises major engineering challenges when developing a full-fledged analyzer for a realistic language such as Java. Efficiency and precision of such a tool rely partly on low level components which only depend on the syntactic structure of the language and therefore should not be redesigned for each implementation of a new static analysis. This paper describes the Sawja library: a static analysis workshop fully compliant with Java 6 which provides OCaml modules for efficiently manipulating Java bytecode programs. We present the main features of the library, including i) efficient functional data-structures for representing a program with implicit sharing and lazy parsing, ii) an intermediate stack-less representation, and iii) fast computation and manipulation of complete programs. We provide experimental evaluations of the different features with respect to time, memory and precision.

  1. Thermal static bending of deployable interlocked booms

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L.; Predmore, R. E.

    1973-01-01

    Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

  2. A static investigation of several STOVL exhaust system concepts

    NASA Technical Reports Server (NTRS)

    Romine, B. M., Jr.; Meyer, B. E.; Re, R. J.

    1989-01-01

    A static cold flow scale model test was performed in order to determine the internal performance characteristics of various STOVL exhaust systems. All of the concepts considered included a vectorable cruise nozzle and a separate vectorable vertical thrust ventral nozzle mounted on the tailpipe. The two ventral nozzle configurations tested featured vectorable constant thickness cascade vanes for area control and improved performance during transition and vertical lift flight. The best transition performance was achieved using a butterfly door type ventral nozzle and a pitch vectoring 2DCD or axisymmetric cruise nozzle. The clamshell blocker type of ventral nozzle had reduced transition performance due to the choking of the tailpipe flow upstream of the cruise nozzle.

  3. A cumulant functional for static and dynamic correlation.

    PubMed

    Hollett, Joshua W; Hosseini, Hessam; Menzies, Cameron

    2016-08-28

    A functional for the cumulant energy is introduced. The functional is composed of a pair-correction and static and dynamic correlation energy components. The pair-correction and static correlation energies are functionals of the natural orbitals and the occupancy transferred between near-degenerate orbital pairs, rather than the orbital occupancies themselves. The dynamic correlation energy is a functional of the statically correlated on-top two-electron density. The on-top density functional used in this study is the well-known Colle-Salvetti functional. Using the cc-pVTZ basis set, the functional effectively models the bond dissociation of H2, LiH, and N2 with equilibrium bond lengths and dissociation energies comparable to those provided by multireference second-order perturbation theory. The performance of the cumulant functional is less impressive for HF and F2, mainly due to an underestimation of the dynamic correlation energy by the Colle-Salvetti functional. PMID:27586903

  4. 30 CFR 57.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...

  5. 30 CFR 57.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...

  6. 30 CFR 57.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...

  7. 30 CFR 57.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...

  8. 30 CFR 57.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static electricity dissipation during loading... MINES Explosives Extraneous Electricity-Surface and Underground § 57.6602 Static electricity dissipation... generates a static electricity hazard— (a) An evaluation of the potential static electricity hazard shall...

  9. Comments on Static vs Kinetic Friction

    NASA Astrophysics Data System (ADS)

    Kessler, Gabriel

    2009-09-01

    I'm writing to comment on the article published in the March edition of The Physics Teacher titled "Choose Wisely: Static or Kinetic Friction—The Power of Dimensionless Plots." As I was reading the article, something caught my eye that I couldn't reconcile with. It was the phrase on page 160 in the first column near the bottom. The statement was that the experimental value for the coefficient of kinetic friction was "unexpectedly greater than the coefficient of static friction!"

  10. A foundational methodology for determining system static complexity using notional lunar oxygen production processes

    NASA Astrophysics Data System (ADS)

    Long, Nicholas James

    This thesis serves to develop a preliminary foundational methodology for evaluating the static complexity of future lunar oxygen production systems when extensive information is not yet available about the various systems under consideration. Evaluating static complexity, as part of a overall system complexity analysis, is an important consideration in ultimately selecting a process to be used in a lunar base. When system complexity is higher, there is generally an overall increase in risk which could impact the safety of astronauts and the economic performance of the mission. To evaluate static complexity in lunar oxygen production, static complexity is simplified and defined into its essential components. First, three essential dimensions of static complexity are investigated, including interconnective complexity, strength of connections, and complexity in variety. Then a set of methods is developed upon which to separately evaluate each dimension. Q-connectivity analysis is proposed as a means to evaluate interconnective complexity and strength of connections. The law of requisite variety originating from cybernetic theory is suggested to interpret complexity in variety. Secondly, a means to aggregate the results of each analysis is proposed to create holistic measurement for static complexity using the Single Multi-Attribute Ranking Technique (SMART). Each method of static complexity analysis and the aggregation technique is demonstrated using notional data for four lunar oxygen production processes.

  11. GPS and Glonass Combined Static Precise Point Positioning (ppp)

    NASA Astrophysics Data System (ADS)

    Pandey, D.; Dwivedi, R.; Dikshit, O.; Singh, A. K.

    2016-06-01

    With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs), satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP), especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment gLAB 2.2.7 as well as magicGNSS software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP) by more than 30%.

  12. Transcranial static magnetic field stimulation of the human motor cortex.

    PubMed

    Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

    2011-10-15

    The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

  13. Static and dynamic deformation effects in the fusion cross section of light heavy ions at sub-barrier energies

    SciTech Connect

    Hussein, M.S.; Canto, L.F.; Donangelo, R.

    1980-02-01

    The static and dynamic deformation effects on the sub-barrier fusion cross section of light heavy ions are investigated by performing a coupled channel calculation for the system /sup 12/C+/sup 16/O. It is found that dynamic effects are negligible whereas static effects could be important, and they appear to show up partly through absorption under the barrier.

  14. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, C. LEE COOK DIVISION, DOVER CORPORATION, STATIC PAC (TM) SYSTEM, PHASE II REPORT

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the Static Pac System, Phase II, natural gas reciprocating compressor rod packing manufactured by the C. Lee Cook Division, Dover Corporation. The Static Pac System is designed to seal th...

  15. Interpretational conflicts between the static and non-static forms of the de Sitter metric

    PubMed Central

    Mitra, Abhas

    2012-01-01

    The de-Sitter metric is a special form of the non-static Friedmann metric, and appears to be genuinely non-static since it describes the initial exponential expansion of the Big Bang universe. However, the de Sitter metric appears to be perfectly static in the Schwarzschild frame where the vacuum fluid is supposed to be in motion. Here we highlight the conflicts between the static and non-static versions of the de-Sitter metric from a physical perspective. In particular, while the “Principle of Energy Conservation” is honored in one case, the same is badly violated for the other. However, we offer a partial resolution of such conflicts by deriving the static de Sitter metric by solving the relevant field equations. It is seen that, it is the very special vacuum equation of state pressure = –density which results in the static form even when the vacuum fluid is supposed to be in motion. PMID:23213359

  16. INTRODUCTION AND STATIC ELECTRICITY, VOLUME 1.

    ERIC Educational Resources Information Center

    KLAUS, DAVID J.; AND OTHERS

    THIS VOLUME, PART OF A TWO-VOLUME SET, PROVIDES AUTOINSTRUCTION IN PHYSICS. THE MATERIAL COVERS UNITS ON (1) STATIC ELECTRICITY AND ELECTRICAL CHARGES, (2) COULOMB'S LAW, (3) DISTRIBUTION OF CHARGE AND FLOW OF CURRENT, (4) DIFFERENCE OF POTENTIAL, (5) BATTERIES AND CIRCUITS, (6) RESISTANCE AND RESISTORS, (7) POTENTIAL DIVIDER AND WHEATSTONE…

  17. Static and evolutionary quantum public goods games

    NASA Astrophysics Data System (ADS)

    Liao, Zeyang; Qin, Gan; Hu, Lingzhi; Li, Songjian; Xu, Nanyang; Du, Jiangfeng

    2008-05-01

    We apply the continuous-variable quantization scheme to quantize public goods game and find that new pure strategy Nash equilibria emerge in the static case. Furthermore, in the evolutionary public goods game, entanglement can also contribute to the persistence of cooperation under various population structures without altruism, voluntary participation, and punishment.

  18. Onthe static and spherically symmetric gravitational field

    NASA Astrophysics Data System (ADS)

    Gottlieb, Ioan; Maftei, Gheorghe; Mociutchi, Cleopatra

    Starting from a generalization of Einstein 's theory of gravitation, proposed by one of the authors (Cleopatra Mociutchi), the authors study a particular spherical symmetric case. Among other one obtain the compatibility conditions for the existence of the static and spherically symmetruic gravitational filed in the case of extended Einstein equation.

  19. A Progression of Static Equilibrium Laboratory Exercises

    ERIC Educational Resources Information Center

    Kutzner, Mickey; Kutzner, Andrew

    2013-01-01

    Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…

  20. Effects of insoles contact on static balance

    PubMed Central

    Shin, Ju Yong; Ryu, Young Uk; Yi, Chae Woo

    2016-01-01

    [Purpose] This study examined the effect of the degree of the contact area between the insoles and soles on static balance. [Subjects and Methods] Thirteen healthy male and female adults voluntarily participated. All of the subjects wore three different types of insoles (no orthotic insole, partial contact, full contact) in the present experiment. The subjects were instructed to place both feet parallel to each other and maintain static balance for 30 seconds. Center of pressure parameters (range, total distance, and mean velocity) were analyzed. [Results] The results show that the anteroposterior range and mediolateral (ML) total distance and velocity decreased when orthotic insoles with partial contact or full contact were used in comparison to when a flat insole (no orthotic insole) was used. Also, the ML range and total distance were lower with full contact than in the other two conditions. These results indicate that static balance improves as the degree of contact between the soles and insoles increases. [Conclusion] The results of this study suggests that using insoles with increased sole contact area would improve static balance ability. PMID:27190460

  1. Model of the static universe within GR

    SciTech Connect

    Karbanovski, V. V. Tarasova, A. S.; Salimova, A. S.; Bilinskaya, G. V.; Sumbulov, A. N.

    2011-01-15

    Within GR, the problems of the Robertson-Walker universe are discussed. The approach based on transition to a nondiagonal line element is suggested. Within the considered approach, the static universe model is investigated. The possibility of constructing scenarios without an initial singularity and 'exotic' matter is discussed. Accordance of the given model to the properties of the observable universe is discussed.

  2. Static Abstractions and the Teaching of Writing.

    ERIC Educational Resources Information Center

    Connors, Robert J.

    The element of static abstractions (SAs)--any pseudoheuristic listing of derived nominals whose purpose is to define good structure in prose writing--is one of the important historical components of the current traditional rhetoric inherited from the nineteenth century. SAs, of which unity, coherence, and emphasis are the best known examples, have…

  3. Static var compensators stabilize power voltages

    SciTech Connect

    Burch, R.

    1996-06-01

    This article discusses the operation of a static var compensator as installed by Alabama Power near a steel mill with a large arc furnace load. This is expected to result in a number of benefits, including flicker reduction, dynamic power factor correction, harmonics filtering and a reduction in system losses.

  4. Static black hole uniqueness and Penrose inequality

    SciTech Connect

    Mizuno, Ryosuke; Shiromizu, Tetsuya; Ohashi, Seiju

    2010-02-15

    Under certain conditions, we offer a new way to prove the uniqueness of the static black hole in higher dimensional asymptotically flat spacetimes. In the proof, the Penrose inequality plays a key role in higher dimensions as well as four dimensions.

  5. Device measures static friction of magnetic tape

    NASA Technical Reports Server (NTRS)

    Cole, P. T.

    1967-01-01

    Device measures the coefficient of static friction of magnetic tape over a range of temperatures and relative humidities. It uses a strain gage to measure the force of friction between a reference surface and the tape drawn at a constant velocity of approximately 0.0001 inch per second relative to the reference surface.

  6. Hard thermal loops in static external fields

    SciTech Connect

    Frenkel, J.; Takahashi, N.; Pereira, S. H.

    2009-04-15

    We examine, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop integral at zero external energies and momenta.

  7. Static & Dynamic Response of 3D Solids

    Energy Science and Technology Software Center (ESTSC)

    1996-07-15

    NIKE3D is a large deformations 3D finite element code used to obtain the resulting displacements and stresses from multi-body static and dynamic structural thermo-mechanics problems with sliding interfaces. Many nonlinear and temperature dependent constitutive models are available.

  8. Cardiorespiratory deconditioning with static and dynamic leg exercise during bed rest

    NASA Technical Reports Server (NTRS)

    Stremel, R. W.; Convertino, V. A.; Bernauer, E. M.; Greenleaf, J. E.

    1976-01-01

    Results are presented for an experimental study designed to compare the effects of heavy static and dynamic exercise training during 14 days of bed rest on the cardiorespiratory responses to submaximal and maximal exercise performed by seven healthy men aged 19-22 yr. The parameters measured were submaximal and maximal oxygen uptake, minute ventilation, heart rate, and plasma volume. The results indicate that exercise alone during bed rest reduces but does not eliminate the reduction in maximal oxygen uptake. An additional positive hydrostatic effect is therefore necessary to restore maximal oxygen uptake to ambulatory control levels. The greater protective effect of static exercise on maximal oxygen uptake is probably due to a greater hydrostatic component from the isometric muscular contraction. Neither the static nor the dynamic exercise training regimes are found to minimize the changes in all the variables studied, thereby suggesting a combination of static and dynamic exercises.

  9. Summary of static load test of the Mod-0 blade

    NASA Technical Reports Server (NTRS)

    Miller, D. R.

    1978-01-01

    A static load test was performed on the spare Mod-0 wind turbine blade to define load transfer at the root end of the blade, and to validate stress analysis of this particular type of blade construction (frame and stringer). Analysis of the load transfer from the airfoil skin to the shank tube predicted a step change in spanwise stress in the airfoil skin at station 81.5 inches (STA 81.5). For flatwise bending a 40% reduction in spanwise stress was predicted, and for edgewise bending a 6% reduction. Experimental results verified the 40% reduction for flatwise bending, but indicated about a 30% reduction for edgewise bending.

  10. Diagnosing Intermittent and Persistent Faults using Static Bayesian Networks

    NASA Technical Reports Server (NTRS)

    Megshoel, Ole Jakob

    2010-01-01

    Both intermittent and persistent faults may occur in a wide range of systems. We present in this paper the introduction of intermittent fault handling techniques into ProDiagnose, an algorithm that previously only handled persistent faults. We discuss novel algorithmic techniques as well as how our static Bayesian networks help diagnose, in an integrated manner, a range of intermittent and persistent faults. Through experiments with data from the ADAPT electrical power system test bed, generated as part of the Second International Diagnostic Competition (DXC-10), we show that this novel variant of ProDiagnose diagnoses intermittent faults accurately and quickly, while maintaining strong performance on persistent faults.

  11. Decomposition products of TATB under high static pressure

    NASA Astrophysics Data System (ADS)

    Crowhurst, Jonathan; Stavrou, Elissaios; Zaug, Joseph

    We have investigated the decomposition products of 2,4,6-triamino-1,3,5-trinitrobenzene (TATB) at static pressures up to 50 GPa using Raman and IR absorption spectroscopy. Decomposition was driven by various continuous wave and pulsed laser drives. We compare decomposition behavior and products obtained at the different pressures. Preliminary results at lower pressures indicate the formation of carbon dioxide, nitrogen, amorphous carbon and possibly hydrogen. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344

  12. Classification of schizophrenia and bipolar patients using static and dynamic resting-state fMRI brain connectivity.

    PubMed

    Rashid, Barnaly; Arbabshirani, Mohammad R; Damaraju, Eswar; Cetin, Mustafa S; Miller, Robyn; Pearlson, Godfrey D; Calhoun, Vince D

    2016-07-01

    Recently, functional network connectivity (FNC, defined as the temporal correlation among spatially distant brain networks) has been used to examine the functional organization of brain networks in various psychiatric illnesses. Dynamic FNC is a recent extension of the conventional FNC analysis that takes into account FNC changes over short periods of time. While such dynamic FNC measures may be more informative about various aspects of connectivity, there has been no detailed head-to-head comparison of the ability of static and dynamic FNC to perform classification in complex mental illnesses. This paper proposes a framework for automatic classification of schizophrenia, bipolar and healthy subjects based on their static and dynamic FNC features. Also, we compare cross-validated classification performance between static and dynamic FNC. Results show that the dynamic FNC significantly outperforms the static FNC in terms of predictive accuracy, indicating that features from dynamic FNC have distinct advantages over static FNC for classification purposes. Moreover, combining static and dynamic FNC features does not significantly improve the classification performance over the dynamic FNC features alone, suggesting that static FNC does not add any significant information when combined with dynamic FNC for classification purposes. A three-way classification methodology based on static and dynamic FNC features discriminates individual subjects into appropriate diagnostic groups with high accuracy. Our proposed classification framework is potentially applicable to additional mental disorders. PMID:27118088

  13. A quasi-static polynomial nodal method for nuclear reactor analysis

    SciTech Connect

    Gehin, J.C.

    1992-09-01

    Modern nodal methods are currently available which can accurately and efficiently solve the static and transient neutron diffusion equations. Most of the methods, however, are limited to two energy groups for practical application. The objective of this research is the development of a static and transient, multidimensional nodal method which allows more than two energy groups and uses a non-linear iterative method for efficient solution of the nodal equations. For both the static and transient methods, finite-difference equations which are corrected by the use of discontinuity factors are derived. The discontinuity factors are computed from a polynomial nodal method using a non-linear iteration technique. The polynomial nodal method is based upon a quartic approximation and utilizes a quadratic transverse-leakage approximation. The solution of the time-dependent equations is performed by the use of a quasi-static method in which the node-averaged fluxes are factored into shape and amplitude functions. The application of the quasi-static polynomial method to several benchmark problems demonstrates that the accuracy is consistent with that of other nodal methods. The use of the quasi-static method is shown to substantially reduce the computation time over the traditional fully-implicit time-integration method. Problems involving thermal-hydraulic feedback are accurately, and efficiently, solved by performing several reactivity/thermal-hydraulic updates per shape calculation.

  14. Comparative static curing versus dynamic curing on tablet coating structures.

    PubMed

    Gendre, Claire; Genty, Muriel; Fayard, Barbara; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

    2013-09-10

    Curing is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24h of static curing and 4h of dynamic curing, both performed at 60°C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions. PMID:23792043

  15. Static and dynamic analyses of tensegrity structures

    NASA Astrophysics Data System (ADS)

    Nishimura, Yoshitaka

    Tensegrity structures are a class of truss structures consisting of a continuous set of tension members (cables) and a discrete set of compression members (bars). Since tensegrity structures are light weight and can be compactly stowed and deployed, cylindrical tensegrity modules have been proposed for space structures. From a view point of structural dynamics, tensegrity structures pose a new set of problems, i.e., initial shape finding. Initial configurations of tensegrity structures must be computed by imposing a pre-stressability condition to initial equilibrium equations. There are ample qualitative statements regarding the initial geometry of cylindrical and spherical tensegrity modules. Quantitative initial shape anlyses have only been performed on one-stage and two-stage cylindrical modules. However, analytical expressions for important geometrical parameters such as twist angles and overlap ratios lack the definition of the initial shape of both cylindrical and spherical tensegrity modules. In response to the above needs, a set of static and dynamic characterization procedures for tensegrity modules was first developed. The procedures were subsequently applied to Buckminster Fuller's spherical tensegrity modules. Both the initial shape and the corresponding pre-stress mode were analytically obtained by using the graphs of the tetrahedral, octahedral (cubic), and icosahedral (dodecahedral) groups. For pre-stressed configurations, modal analyses were conducted to classify a large number of infinitesimal mechanism modes. The procedures also applied tocyclic cylindrical tensegrity modules with an arbitrary number of stages. It was found that both the Maxwell number and the number of infinitesimal mechanism modes are independent of the number of stages in the axial direction. A reduced set of equilibrium equations was derived by incorporating cyclic symmetry and the flip, or quasi-flip, symmetry of the cylindrical modules. For multi-stage modules with more than

  16. Comparison of Static and Dynamic Balance in Female Collegiate Soccer, Basketball, and Gymnastics Athletes

    PubMed Central

    Bressel, Eadric; Yonker, Joshua C; Kras, John; Heath, Edward M

    2007-01-01

    Context: How athletes from different sports perform on balance tests is not well understood. When prescribing balance exercises to athletes in different sports, it may be important to recognize performance variations. Objective: To compare static and dynamic balance among collegiate athletes competing or training in soccer, basketball, and gymnastics. Design: A quasi-experimental, between-groups design. Independent variables included limb (dominant and nondominant) and sport played. Setting: A university athletic training facility. Patients or Other Participants: Thirty-four female volunteers who competed in National Collegiate Athletic Association Division I soccer (n = 11), basketball (n = 11), or gymnastics (n = 12). Intervention(s): To assess static balance, participants performed 3 stance variations (double leg, single leg, and tandem leg) on 2 surfaces (stiff and compliant). For assessment of dynamic balance, participants performed multidirectional maximal single-leg reaches from a unilateral base of support. Main Outcome Measure(s): Errors from the Balance Error Scoring System and normalized leg reach distances from the Star Excursion Balance Test were used to assess static and dynamic balance, respectively. Results: Balance Error Scoring System error scores for the gymnastics group were 55% lower than for the basketball group (P = .01), and Star Excursion Balance Test scores were 7% higher in the soccer group than the basketball group (P = .04). Conclusions: Gymnasts and soccer players did not differ in terms of static and dynamic balance. In contrast, basketball players displayed inferior static balance compared with gymnasts and inferior dynamic balance compared with soccer players. PMID:17597942

  17. Static investigation of circular-to-rectangular transition ducts for high-aspect-ratio nonaxisymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Burley, J. R., II; Bangert, L. S.; Carlson, J. R.

    1986-01-01

    An investigation was conducted in the static-test facility of the Langley 16-Foot Transonic Tunnel to determine the internal performance of a high-aspect-ratio nonaxisymmetric nozzle with five circular-to-rectangular transition ducts of varying design. Nozzle pressure ratio was varied from 1.5 to 5.3, and nozzle performance parameters were recorded.

  18. Static shape control for flexible structures

    NASA Technical Reports Server (NTRS)

    Rodriguez, G.; Scheid, R. E., Jr.

    1986-01-01

    An integrated methodology is described for defining static shape control laws for large flexible structures. The techniques include modeling, identifying and estimating the control laws of distributed systems characterized in terms of infinite dimensional state and parameter spaces. The models are expressed as interconnected elliptic partial differential equations governing a range of static loads, with the capability of analyzing electromagnetic fields around antenna systems. A second-order analysis is carried out for statistical errors, and model parameters are determined by maximizing an appropriate defined likelihood functional which adjusts the model to observational data. The parameter estimates are derived from the conditional mean of the observational data, resulting in a least squares superposition of shape functions obtained from the structural model.

  19. Shock and Static Compression of Nitrobenzene

    NASA Astrophysics Data System (ADS)

    Kozu, Naoshi; Arai, Mitsuru; Tamura, Masamitsu; Fujihisa, Hiroshi; Aoki, Katsutoshi; Yoshida, Masatake

    2000-08-01

    The Hugoniot and static compression curve (isotherm) were investigated using explosive plane wave generators and diamond anvil cells, respectively. The obtained Hugoniot from the shock experiments is represented by two linear lines: Us=2.52+1.23 up (0.8static high pressure over 7 GPa, nitrobenzene undergoes a reaction that is expected to be polymerization. Considering the Hugoniot and the isotherm, it is plausible that shocked nitrobenzene (<15 GPa) is in the liquid state.

  20. Variational approach for static mirror structures

    SciTech Connect

    Kuznetsov, E. A.; Passot, T.; Sulem, P. L.; Ruban, V. P.

    2015-04-15

    Anisotropic static plasma equilibria where the parallel and perpendicular pressures are only functions of the amplitude of the local magnetic field are shown to be amenable to a variational principle with a free energy density given by the parallel tension. This approach is used to demonstrate that two-dimensional small-amplitude static magnetic holes constructed from a Grad-Shafranov type equation slightly below the (subcritical) mirror instability threshold identify with lump solitons of KPII equation, but turn out to be unstable. Differently, large-amplitude magnetic structures, which are stable as they realize a minimum of the free energy, are computed using a gradient method within two-dimensional numerical simulations where the regularizing effect of finite Larmor radius corrections is retained. Interestingly, these structures transform from stripes to bubbles when the angle of the magnetic field with the coordinate plane is increased.

  1. Static spherically symmetric wormholes with isotropic pressure

    NASA Astrophysics Data System (ADS)

    Cataldo, Mauricio; Liempi, Luis; Rodríguez, Pablo

    2016-06-01

    In this paper we study static spherically symmetric wormhole solutions sustained by matter sources with isotropic pressure. We show that such spherical wormholes do not exist in the framework of zero-tidal-force wormholes. On the other hand, it is shown that for the often used power-law shape function there are no spherically symmetric traversable wormholes sustained by sources with a linear equation of state p = ωρ for the isotropic pressure, independently of the form of the redshift function ϕ (r). We consider a solution obtained by Tolman at 1939 for describing static spheres of isotropic fluids, and show that it also may describe wormhole spacetimes with a power-law redshift function, which leads to a polynomial shape function, generalizing a power-law shape function, and inducing a solid angle deficit.

  2. Automated static perimetry to evaluate diabetic retinopathy.

    PubMed Central

    Federman, J L; Lloyd, J

    1984-01-01

    The Octopus automated static perimeter was used to evaluate patients with early diabetic retinopathy. It showed islands of threshold sensitivity depression that were equal to areas of nonperfusion seen on fluorescein angiography. The geographic area of the fundus at risk of developing these field defects was found to be between 20 and 45 degrees, representing the central area of the midperiphery. This procedure has potential as an excellent screening test for early diabetic retinopathy. Images FIGURE 1 (Cont'd) C PMID:6549516

  3. Analyzing Static Loading of Complex Structures

    NASA Technical Reports Server (NTRS)

    Gallear, D. C.

    1986-01-01

    Critical loading conditions determined from analysis of each structural element. Automated Thrust Structures Loads and Stresses (ATLAS) system is series of programs developed to analyze elements of complex structure under static-loading conditions. ATLAS calculates internal loads, beam-bending loads, column- and web-buckling loads, beam and panel stresses, and beam-corner stresses. Programs written in FORTRAN IV and Assembler for batch execution.

  4. Generating static fluid spheres by conformal transformations

    SciTech Connect

    Loranger, Jonathan; Lake, Kayll

    2008-12-15

    We generate an explicit four-fold infinity of physically acceptable exact perfect fluid solutions of Einstein's equations by way of conformal transformations of physically unacceptable solutions (one way to view the use of isotropic coordinates). Special cases include the Schwarzschild interior solution and the Einstein static universe. The process we consider involves solving two equations of the Riccati type coupled by a single generating function rather than a specification of one of the two metric functions.

  5. Manipulating Cells with Static Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Valles, J. M.; Guevorkian, K.

    2005-07-01

    We review our investigations of the use of static magnetic fields, B, for manipulating cells and cellular processes. We describe how B fields modify the cell division pattern of frog embryos and consequently can be used to probe the pattern determinants. We also observe that magnetic fields modify the swimming behavior of Paramecium Caudatum. We describe these modifications and their potential application to investigations of their swimming behavior.

  6. Geodesics in the static Mallett spacetime

    SciTech Connect

    Olum, Ken D.

    2010-06-15

    Mallett has exhibited a cylindrically symmetric spacetime containing closed timelike curves produced by a light beam circulating around a line singularity. I analyze the static version of this spacetime obtained by setting the intensity of the light to zero. Some null geodesics can escape to infinity, but all timelike geodesics in this spacetime originate and terminate at the singularity. Freely falling matter originally at rest quickly attains relativistic velocity inward and is destroyed at the singularity.

  7. Calibration of a pitot-static rake

    NASA Technical Reports Server (NTRS)

    Stump, H. P.

    1977-01-01

    A five-element pitot-static rake was tested to confirm its accuracy and determine its suitability for use at Langley during low-speed tunnel calibration primarily at full-scale tunnel. The rake was tested at one airspeed of 74 miles per hour (33 meters per second) and at pitch and yaw angles of 0 to + or - 20 degrees in 4 deg increments.

  8. Recent studies using static simulation techniques

    NASA Astrophysics Data System (ADS)

    Catlow, C. R. A.; Freeman, C. M.; Royle, R. L.

    1985-08-01

    We review contemporary applications of static simulation methods based on energy minimisation techniques. The scope and limitations of the techniques are described. Particular attention is paid to the nature of the interatomic potentials used in such calculations. Applications are described to (i) modelling of SiO 2; (ii) prediction of conformations of the polypeptide enkephalin; (iii) the properties of impurities in TiO 2.

  9. Static forces in a superconducting magnet bearing

    SciTech Connect

    Stoye, P.; Fuchs, G.; Gawalek, W.; Goernert, P.; Gladun, A.

    1995-11-01

    Static levitation forces and stiffnesses in a superconducting bearing consisting of concentric ring magnets and a superconducting YBaCuO ring are investigated. In the field-cooled mode a levitation force of 20 N has been achieved. The axial and radial stiffnesses have values of 15 N/mm and 10 N/mm, respectively. An arrangement with two bearings supporting a high speed shaft is now under development. A possible application of superconducting magnetic bearings is flywheels for energy storage.

  10. 4500 V SPT+ IGBT optimization on static and dynamic losses

    NASA Astrophysics Data System (ADS)

    Qingyun, Dai; Xiaoli, Tian; Wenliang, Zhang; Shuojin, Lu; Yangjun, Zhu

    2015-09-01

    This paper concerns the need for improving the static and dynamic performance of the high voltage insulated gate bipolar transistor (HV IGBTs). A novel structure with a carrier stored layer on the cathode side, known as an enhanced planar IGBT of the 4500 V voltage class is investigated. With the adoption of a soft punch through (SPT) concept as the vertical structure and an enhanced planar concept as the top structure, signed as SPT+ IGBT, the simulation results indicate the turn-off switching waveform of the 4500 V SPT+ IGBT is soft and also realizes an improved trade-off relationship between on-state voltage drop (Von) and turn-off loss (Eoff) in comparison with the SPT IGBT. Attention is also paid to the influences caused by different carrier stored layer doping dose on static and dynamic performances, to optimize on-state and switching losses of SPT+ IGBT. Project supported by the National Major Science and Technology Special Project of China (No. 2011ZX02504-002).

  11. Propfan test assessment propfan propulsion system static test report

    NASA Technical Reports Server (NTRS)

    Orourke, D. M.

    1987-01-01

    The propfan test assessment (PTA) propulsion system successfully completed over 50 hours of extensive static ground tests, including a 36 hour endurance test. All major systems performed as expected, verifying that the large-scale 2.74 m diameter propfan, engine, gearbox, controls, subsystems, and flight instrumentation will be satisfactory with minor modifications for the upcoming PTA flight tests on the GII aircraft in early 1987. A test envelope was established for static ground operation to maintain propfan blade stresses within limits for propfan rotational speeds up to 105 percent and power levels up to 3880 kW. Transient tests verified stable, predictable response of engine power and propfan speed controls. Installed engine TSFC was better than expected, probably due to the excellent inlet performance coupled with the supercharging effect of the propfan. Near- and far-field noise spectra contained three dominant components, which were dependent on power, tip speed, and direction. The components were propfan blade tones, propfan random noise, and compressor/propfan interaction noise. No significant turbine noise or combustion noise was evident.

  12. Slinky Mechanics: Static Shapes and Unstable States

    NASA Astrophysics Data System (ADS)

    Holmes, Douglas; Borum, Andy; Moore, Billy; Plaut, Raymond; Dillard, David

    2014-03-01

    The floppy nature of a tumbling Slinky has captivated children and adults alike for over half a century. Highly flexible, the spring will walk down stairs, turn over in your hands, and-much to the chagrin of children everywhere-become easily entangled. The Slinky is an educational tool for demonstrating standing waves, and a structural inspiration due to its ability to extend to many times beyond its initial length without imparting plastic strain on the material. In this work, we provide a mechanical model that captures the static equilibrium configurations of the Slinky in terms of its geometric and material properties. We present both continuous and discrete models to capture a Slinky's static equilibria and unstable transitions. We compare these with experimental results obtained for the Slinky's static equilibrium shapes. We emphasize the importance of modeling coil contact, and determine the critical criteria for the Slinky to topple over in terms of a tilt angle, and the vertical displacement of one bale of coils. Finally, we provide a general description of highly flexible helical springs by considering the nondimensional potential energy of the spring, which characterizes the ``Slinkiness'' of a spring.

  13. Characterization of Space Shuttle Reusable Rocket Motor Static Test Stand Thrust Measurements

    NASA Technical Reports Server (NTRS)

    Cook, Mart L.; Gruet, Laurent; Cash, Stephen F. (Technical Monitor)

    2003-01-01

    Space Shuttle Reusable Solid Rocket Motors (RSRM) are static tested at two ATK Thiokol Propulsion facilities in Utah, T-24 and T-97. The newer T-97 static test facility was recently upgraded to allow thrust measurement capability. All previous static test motor thrust measurements have been taken at T-24; data from these tests were used to characterize thrust parameters and requirement limits for flight motors. Validation of the new T-97 thrust measurement system is required prior to use for official RSRM performance assessments. Since thrust cannot be measured on RSRM flight motors, flight motor measured chamber pressure and a nominal thrust-to-pressure relationship (based on static test motor thrust and pressure measurements) are used to reconstruct flight motor performance. Historical static test and flight motor performance data are used in conjunction with production subscale test data to predict RSRM performance. The predicted motor performance is provided to support Space Shuttle trajectory and system loads analyses. Therefore, an accurate nominal thrust-to-pressure (F/P) relationship is critical for accurate RSRM flight motor performance and Space Shuttle analyses. Flight Support Motors (FSM) 7, 8, and 9 provided thrust data for the validation of the T-97 thrust measurement system. The T-97 thrust data were analyzed and compared to thrust previously measured at T-24 to verify measured thrust data and identify any test-stand bias. The T-97 FIP data were consistent and within the T-24 static test statistical family expectation. The FSMs 7-9 thrust data met all NASA contract requirements, and the test stand is now verified for future thrust measurements.

  14. Adjoint Optimization of Multistage Axial Compressor Blades with Static Pressure Constraint at Blade Row Interface

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Ji, Lucheng; Li, Weiwei; Yi, Weilin

    2016-06-01

    Adjoint method is an important tool for design refinement of multistage compressors. However, the radial static pressure distribution deviates during the optimization procedure and deteriorates the overall performance, producing final designs that are not well suited for realistic engineering applications. In previous development work on multistage turbomachinery blade optimization using adjoint method and thin shear-layer N-S equations, the entropy production is selected as the objective function with given mass flow rate and total pressure ratio as imposed constraints. The radial static pressure distribution at the interfaces between rows is introduced as a new constraint in the present paper. The approach is applied to the redesign of a five-stage axial compressor, and the results obtained with and without the constraint on the radial static pressure distribution at the interfaces between rows are discussed in detail. The results show that the redesign without the radial static pressure distribution constraint (RSPDC) gives an optimal solution that shows deviations on radial static pressure distribution, especially at rotor exit tip region. On the other hand, the redesign with the RSPDC successfully keeps the radial static pressure distribution at the interfaces between rows and make sure that the optimization results are applicable in a practical engineering design.

  15. The effects of deuterium on static posture control

    NASA Technical Reports Server (NTRS)

    Layne, Charles S.

    1990-01-01

    A significant operational problem impacting upon the Space Shuttle program involves the astronaut's ability to safely egress from the Orbiter during an emergency situation. Following space flight, astronauts display significant movement problems. One variable which may contribute to increased movement ataxia is deuterium (D2O). Deuterium is present in low levels within the Orbiter's water supply but may accumulate to significant physiological levels during lengthy missions. Deuterium was linked to a number of negative physiological responses, including motion sickness, decreased metabolism, and slowing of neural conduction velocity. The effects of D2O on static postural control in response to a range of dosage levels were investigated. Nine sugjects were divided into three groups of three subjects each. The groups were divided into a low, medium, and a high D2O dosage group. The subjects static posture was assessed with the use of the EquiTest systems, a commercially available postural control evaluation system featuring movable force plates and a visual surround that can be servoed to the subject's sway. In addition to the force plate information, data about the degree of subject sway about the hips and shoulders was obtained. Additionally, surface electromyographic (EMG) data from the selected lower limb muscles were collected along with saliva samples used to determine the amount of deuterium enrichment following D2O ingestion. Two baseline testing sessions were performed using the EquiTest testing protocol prior to ingestion of the D2O. Thirty minutes after dosing, subjects again performed the tests. Two more post-dosing tests were run with an interest interval of one hour. Preliminary data anlaysis indicates that only subjects in the igh dose group displayed any significant static postural problems. Future analyses of the sway and EMG is expected to reveal significant variations in the subject's postural control strategy following D2O dosing. While

  16. On Static Pressure Fluctuation between Sirocco Fan Blades in a Car Air-Conditioning System

    NASA Astrophysics Data System (ADS)

    Sakai, Yasuhiko; Kato, Takaaki; Moriguchi, Yuu; Sakai, Masaharu; Ito, Kouji; Mitsuishi, Yasushi; Nagata, Kouji; Kubo, Takashi

    In this study, special attention is directed to static pressure fluctuation in a sirocco fan for a car air-conditioning system, because it is expected that there is a close connection between the fluid noise and the pressure fluctuation. The final purpose of this study is to clarify the relationship between the static pressure fluctuation between fan blades and the sound noise emitted to the outside of the fan, and to develop an air-conditioning system with highly low noise level. For this purpose, first of all, a new micro probe for the measurement of static pressure fluctuation has been developed. This new micro probe is composed of an L-type static pressure tube (the outer diameter is 0.5 mm and the inner diameter is 0.34 mm) and a very small pressure transducer. This probe exhibits a flat frequency response until approximately 2,000 Hz, and it is set between the blades of the fan rotating at 1,500 rpm. The measurements of the static pressure fluctuation between the blades have been performed, and the intensity of sound source was quantified from the second derivative of the phase-averaged static pressure fluctuation signals on the basis of Ribner's formula (Ribner 1962). The experiments have been made in two different modes, i.e., the cooling mode (FACE MODE) and the heating mode (FOOT MODE). It is shown that the static pressure increases rapidly as the blade approaches to the nose of the casing. It is also found that the sound source for FACE MODE shows the larger value than that for FOOT MODE as a whole. In particular, the largest intensity of sound source is observed when the blade approaches to the nose. From these results, it is confirmed that the present new static pressure probe is useful to specify the distributions of sound source in a sirocco fan.

  17. A multimode DLL with trade-off between multiphase and static phase error

    NASA Astrophysics Data System (ADS)

    Dandan, Zhang; Wenrui, Zhu; Wei, Li; Zhihong, Huang; Lijiang, Gao; Haigang, Yang

    2014-05-01

    A multimode DLL with trade-off between multiphase and static phase error is presented. By adopting a multimode control circuit to regroup the delay line, a better static phase error performance can be achieved while reducing the number of output phases. The DLL accomplishes three operation modes: mode1 with a four-phase output, mode2 with a two-phase output and a better static phase error performance, and mode3 with only a one-phase output but the best static phase error performance. The proposed DLL has been fabricated in 0.13 μm CMOS technology and measurement results show that the static phase errors of mode1, mode2 and mode3 are -18.2 ps, 11.8 ps and -6:44 ps, respectively, at 200 MHz. The measured RMS and peak-to-peak jitters of mode1, mode2 and mode3 are 2.0 ps, 2.2 ps, 2.1 ps and 10 ps, 9.3 ps, 10 ps respectively.

  18. What Sexual Recidivism Rates Are Associated With Static-99R and Static-2002R Scores?

    PubMed

    Hanson, R Karl; Thornton, David; Helmus, Leslie-Maaike; Babchishin, Kelly M

    2016-04-01

    Empirical actuarial risk tools are routinely used to assess the recidivism risk of adult sexual offenders. Compared with other forms of risk assessment, one advantage of actuarial risk tools is that they provide recidivism rate estimates. Previous research, however, suggests that there is considerable variability in the recidivism rates associated with the most commonly used sexual offender risk assessment tools (Static-99/R, Static-2002/R). The current study examined the extent to which the variability in the recidivism rates across 21 Static-99R studies (N = 8,805) corresponded to the normative groups proposed by the STATIC development group (routine, treatment, high risk/high need). We found strong evidence that routine (i.e., complete) samples were, on average, less likely to reoffend with a sexual offense than offenders in the high-risk/high-need samples (i.e., those explicitly preselected on risk-relevant variables external to STATIC scales). The differences between routine/complete and high-risk/high-need samples, however, were only consistently observed for offenders with low or moderate scores; for offenders with high STATIC scores, the 5-year sexual recidivism rates for these two groups were not meaningfully different. There was only limited evidence to support treatment samples as a distinct sample type; consequently, the use of separate normative tables for treatment samples is not recommended. The current results reinforce the value of regularly updating the norms for empirical actuarial risk tools. Options are discussed on how STATIC scores could be used to inform recidivism rates estimates in applied assessments. PMID:25810478

  19. WINDROW AND STATIC PILE COMPOSTING OF MUNICIPAL SEWAGE SLUDGES

    EPA Science Inventory

    Research was conducted on composting anaerobically digested and centrifuge dewatered sewage sludge from 1975 through 1980. Windrow and static pile composting processes were evaluated; new methods were employed using deeper windrows and aerated static piles were constructed withou...

  20. Static tensile and tensile creep testing of four boron nitride coated ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Coguill, Scott L.; Adams, Donald F.; Zimmerman, Richard S.

    1989-01-01

    Six types of uncoated ceramic fibers were static tensile and tensile creep tested at various elevated temperatures. Three types of boron nitride coated fibers were also tested. Room temperature static tensile tests were initially performed on all fibers, at gage lengths of 1, 2, and 4 inches, to determine the magnitude of end effects from the gripping system used. Tests at one elevated temperature, at gage lengths of 8 and 10 inches, were also conducted, to determine end effects at elevated temperatures. Fiber cross sectional shapes and areas were determined using scanning electron microscopy. Creep testing was typically performed for 4 hours, in an air atmosphere.

  1. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  2. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  3. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static pressure systems. 25.1325 Section 25... pressure systems. (a) Each instrument with static air case connections must be vented to the...

  4. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  5. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static pressure systems. 25.1325 Section 25... pressure systems. (a) Each instrument with static air case connections must be vented to the...

  6. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static pressure systems. 25.1325 Section 25... pressure systems. (a) Each instrument with static air case connections must be vented to the...

  7. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  8. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  9. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static pressure systems. 25.1325 Section 25... pressure systems. (a) Each instrument with static air case connections must be vented to the...

  10. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static pressure systems. 25.1325 Section 25... pressure systems. (a) Each instrument with static air case connections must be vented to the...

  11. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  12. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  13. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  14. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  15. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  16. 14 CFR 27.610 - Lightning and static electricity protection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk...

  17. 30 CFR 56.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...

  18. 14 CFR 27.610 - Lightning and static electricity protection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk...

  19. 30 CFR 56.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...

  20. The Static Ladder Problem with Two Sources of Friction

    ERIC Educational Resources Information Center

    Bennett, Jonathan; Mauney, Alex

    2011-01-01

    The problem of a ladder leaning against a wall in static equilibrium is a classic example encountered in introductory mechanics texts. Most discussions of this problem assume that the static frictional force between the ladder and wall can be ignored. A few authors consider the case where the static friction coefficients between ladder/wall…

  1. 14 CFR 27.610 - Lightning and static electricity protection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk...

  2. 14 CFR 27.610 - Lightning and static electricity protection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk...

  3. 14 CFR 27.610 - Lightning and static electricity protection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Lightning and static electricity protection....610 Lightning and static electricity protection. (a) The rotorcraft must be protected against... static electricity must— (1) Minimize the accumulation of electrostatic charge; (2) Minimize the risk...

  4. 30 CFR 56.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...

  5. 30 CFR 56.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...

  6. 30 CFR 56.6602 - Static electricity dissipation during loading.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static electricity dissipation during loading... Explosives Extraneous Electricity § 56.6602 Static electricity dissipation during loading. When explosive material is loaded pneumatically into a blasthole in a manner that generates a static electricity...

  7. 17 CFR 229.1105 - (Item 1105) Static pool information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 2 2011-04-01 2011-04-01 false (Item 1105) Static pool....1105 (Item 1105) Static pool information. (a) For amortizing asset pools, unless the registrant determines that such information is not material: (1) Provide static pool information, to the extent...

  8. Static Enforcement of Static Separation-of-Duty Policies in Usage Control Authorization Models

    NASA Astrophysics Data System (ADS)

    Lu, Jianfeng; Li, Ruixuan; Hu, Jinwei; Xu, Dewu

    Separation-of-Duty (SoD) is a fundamental security principle for prevention of fraud and errors in computer security. It has been studied extensively in traditional access control models. However, the research of SoD policy in the recently proposed usage control (UCON) model has not been well studied. This paper formulates and studies the fundamental problem of static enforcement of static SoD (SSoD) policies in the context of UCONA, a sub-model of UCON only considering authorizations. Firstly, we define a set-based specification of SSoD policies, and the safety checking problem for SSoD in UCONA. Secondly, we study the problem of determining whether an SSoD policy is enforceable. Thirdly, we show that it is intractable (coNP-complete) to direct statically enforce SSoD policies in UCONA, while checking whether a UCONA state satisfies a set of static mutually exclusive attribute (SMEA) constraints is efficient, which provides a justification for using SMEA constraints to enforce SSoD policies. Finally, we introduce a indirect static enforcement for SSoD policies in UCONA. We show how to generate the least restrictive SMEA constraints for enforcing SSoD policies in UCONA, by using the attribute-level SSoD requirement as an intermediate step. The results are fundamental to understanding SSoD policies in UCON.

  9. Effect of environmental humidity on static foam stability.

    PubMed

    Li, Xueliang; Karakashev, Stoyan I; Evans, Geoffrey M; Stevenson, Paul

    2012-03-01

    The quality of foaming products (such as beer and shampoo) and the performance of industrial processes that harness foam (such as the froth flotation of minerals or the foam fractionation of proteins) depend upon foam stability. In this study, experiments are performed to study the effect of environmental humidity on the collapse of static foams. The dependency of the rate at which a foam collapses upon humidity is demonstrated, and we propose a hypothesis for bubble bursting due to Marangoni instability induced by nonuniform evaporation to help explain the dependency. This hypothesis is supported by direct experimental observations of the bursting process of isolated bubbles by high speed video recording and the thinning of isolated foam films under different values of humidity and temperature by microinterferometric methods. PMID:22303917

  10. Ccaffeine framework : composing and debugging applications interactively and running them statically.

    SciTech Connect

    Armstrong, Robert C.; Allan, Benjamin A.

    2005-02-01

    Ccaffeine is a Common Component Architecture (CCA) framework devoted to high-performance computing. In this note we give an overview of the system features of Ccaffeine and CCA that support component-based HPC application development. Object-oriented, single-threaded and lightweight, Ccaffeine is designed to get completely out of the way of the running application after it has been composed from components. Ccaffeine is one of the few frameworks, CCA or otherwise, that can compose and run applications on a parallel machine interactively and then automatically generate a static, possibly self-tuning, executable for production runs. Users can experiment with and debug applications interactively, improving their productivity. When the application is ready, a script is automatically generated, parsed and turned into a static executable for production runs. Within this static executable, dynamic replacement of components can be performed by self-tuning applications.

  11. Acceleration of a static observer near the event horizon of a static isolated black hole

    NASA Astrophysics Data System (ADS)

    Doughty, Noel A.

    1981-05-01

    The magnitude of the proper acceleration of a static observer (or test particle) in a static, isolated, spherically symmetric space-time region is compared with the Newtonian result including the situation in the interior of a perfect-fluid star. The calculation shows that the proper acceleration diverges on the event horizon of a spherically symmetric black hole. The 'surface gravity' of a spherically symmetric black hole, as used in descriptions of the Hawking radiation, is then explicitly related to the accelerations of such static observers, thus providing a simple physical interpretation of the surface gravity and illustrating the global (nonlocal) nature of the event horizon. The calculations are presented in the SI physical equations used almost exclusively by many students and teachers of physics.

  12. LLNL small-scale static spark machine: static spark sensitivity test

    SciTech Connect

    Foltz, M F; Simpson, L R

    1999-08-23

    Small-scale safety testing of explosives and other energetic materials is done in order to determine their sensitivity to various stimuli, such as friction, static spark, and impact. Typically this testing is done to discover potential handling problems that may exist for either newly synthesized materials of unknown behavior, or materials that have been stored for long periods of time. This report describes the existing ''Static Spark Test Apparatus'' at Lawrence Livermore National Laboratory (LLNL), as well as the method used to evaluate the relative static spark sensitivity of energetic materials. The basic design, originally developed by the Picatinny Arsenal in New Jersey, is discussed. The accumulated data for the materials tested to date is not included here, with the exception of specific examples that have yielded interesting or unusual results during the tests.

  13. Relieving the effect of static load errors in nonlinear vibration isolation mounts through stiffness asymmetries

    NASA Astrophysics Data System (ADS)

    Shaw, A. D.; Neild, S. A.; Friswell, M. I.

    2015-03-01

    High Static Low Dynamic Stiffness (HSLDS) mounts consist of nonlinear springs that support a high static load with low static displacement, whilst maintaining locally low stiffness near equilibrium, to give a low natural frequency and consequently good isolation properties. Recent analysis has investigated such devices when the force-displacement relationship is an odd function about the equilibrium position, and analysed the consequences of different shapes of these functions. However many devices that have the HSLDS characteristic do not meet the assumptions of this analysis, in that the force-displacement relationship is generally asymmetric about equilibrium. Furthermore, even devices that do meet this assumption may be subject to significant adjustment error, particularly in the context of air vehicles where manoeuvres such as banked turns can cause an apparent variation in gravitational acceleration, and a consequent variation in the weight of the payload. This change in static load moves the payload away from its intended region of low stiffness. The current paper provides analysis of these situations, and shows that the performance of a mount with a symmetric stiffness-displacement relationship is highly sensitive to errors in the static loading. It is then shown that a mount with an asymmetric stiffness-displacement function can offer significant performance advantages when there are adjustment errors in the loading of the mount.

  14. Modeling static and dynamic detection of humans in rural terrain

    NASA Astrophysics Data System (ADS)

    Flug, Eric

    2014-05-01

    Historically, the focus of detection experiments and modeling at the Night Vision and Electronic Sensors Directorate (NVESD) has been on detecting military vehicles in rural terrains. A gap remains in understanding the detection of human targets in rural terrains and how it might differ from detection of vehicles. There are also improvements that can be made in how to quantify the effect of human movement on detectability. Two experiments were developed to look at probability of detection and time to detect fully exposed human targets in a low to moderate clutter environment in the infrared waveband. The first test uses static images of standing humans while the second test uses videos of humans walking across the scene at various ranges and speeds. Various definitions of target and background areas are explored to calculated contrast and target size. Ultimately, task difficulty parameters (V50s) are calculated to calibrate NVESD sensor performance models, specifically NVThermIP and NV-IPM, for the human detection task. The focus of the analysis in this paper is primarily on the static detection task since the analysis for the dynamic detection experiment is still in the early stages. Results will be presented as well as a plan for future work in this area.

  15. Static stress triggering explains the empirical aftershock distance decay

    NASA Astrophysics Data System (ADS)

    Hainzl, Sebastian; Moradpour, Javad; Davidsen, Jörn

    2014-12-01

    The shape of the spatial aftershock decay is sensitive to the triggering mechanism and thus particularly useful for discriminating between static and dynamic stress triggering. For California seismicity, it has been recently recognized that its form is more complicated than typically assumed consisting of three different regimes with transitions at the scale of the rupture length and the thickness of the crust. The intermediate distance range is characterized by a relative small decay exponent of 1.35 previously declared to relate to dynamic stress triggering. We perform comprehensive simulations of a simple clock-advance model, in which the number of aftershocks is just proportional to the Coulomb-stress change, to test whether the empirical result can be explained by static stress triggering. Similarly to the observations, the results show three scaling regimes. For simulations adapted to the depths and focal mechanisms observed in California, we find a remarkable agreement with the observation over the whole distance range for a fault distribution with fractal dimension of 1.8, which is shown to be in good agreement with an independent analysis of California seismicity.

  16. Auxetic compliant flexible PU foams: static and dynamic properties

    NASA Astrophysics Data System (ADS)

    Scarpa, F.; Pastorino, P.; Garelli, A.; Patsias, S.; Ruzzene, M.

    2005-03-01

    The paper describes the manufacturing and tensile testing of auxetic (negative Poisson's ratio) thermoplastic polyurethane foams, both under constant strain rate and sinusoidal excitation. The foams are produced from conventional flexible polyurethane basis following a manufacturing route developed in previous works. The Poisson's ratio behaviour over tensile strain has been analyzed using an Image Data processing technique based on Edge Detection from digital images recorded during quasi-static tensile test. The samples have been subjected to tensile and compressive tests at quasi-static and constant strain-rate values (up to 12 s-1). Analogous tests have been performed over iso-volumetric foams samples, i.e., foams subjected to the same volumetric compression of the auxetic ones, exhibiting a near zero Poisson's ratio behaviour. The auxetic and non-auxetic foams have been also tested under sinusoidal cycling load up to 10 Hz, with maximum pre-strain applied of 12%. The hysteresis of the cycling loading curve has been measured to determine the damping hysteretic loss factor for the various foams. The measurements indicate that auxetic foams have increased damping loss factor of 20% compared to the conventional foams. The energy dissipation is particularly relevant in the tensile segment of the curve, with effects given by the pre-strain level imposed on the samples.

  17. Technology advancement of the static feed water electrolysis process

    NASA Technical Reports Server (NTRS)

    Jensen, F. C.; Schubert, F. H.

    1977-01-01

    Some results are presented of a research and development program to continue the development of a method to generate oxygen for crew metabolic consumption during extended manned space flights. The concept being pursued is that of static feed water electrolysis. Specific major results of the work included: (1) completion of a 30-day electrode test using a Life Systems, Inc.-developed high performance catalyst. During startup the cell voltages were as low as 1.38 V at current densities of 108 mA/sq cm (100 ASF) and temperatures of 355 K (180 F). At the end of 30 days of testing the cell voltages were still only 1.42 V at 108 mA/sq cm, (2) determination that the Static Feed Water Electrolysis Module does not release an aerosol of the cell electrolyte into the product gas streams after a break-in period of 24 hours following a new electrolyte charge, and (3) completion of a detailed design analysis of an electrochemical Oxygen Generation Subsystem at a three-man level (4.19 kg/day (9.24 lb/day) of oxygen).

  18. Static and kinematic positioning using WADGPS from geostationary satellites

    NASA Astrophysics Data System (ADS)

    Cefalo, R.; Gatti, M.

    2003-04-01

    STATIC AND KINEMATIC POSITIONING USING WADGPS CORRECTIONS FROM GEOSTATIONARY SATELLITES Cefalo R. (1), Gatti M (2) (1) Department of Civil Engineering, University of Trieste, P.le Europa 1, 34127 Trieste, Italy, cefalo@dic.univ.trieste.it, (2) Department of Engineering, University of Ferrara, via Saragat 1, 44100 Ferrara, Italy, mgatti@ing.unife.it ABSTRACT. Starting from February 2000, static and kinematic experiments have been performed at the Department of Civil Engineering of University of Trieste, Italy and the Department of Engineering of University of Ferrara, Italy, using the WADGPS (Wide Area Differential GPS) corrections up linked by Geostationary Satellites belonging to the American WAAS and European EGNOS. Recently, a prototypal service by ESA (European Space Agency) named SISNet (Signal In Space through Internet), has been introduced using Internet to diffuse the messages up linked through AOR-E and IOR Geostationary Satellites. This service will overcome the problems relative to the availability of the corrections in urban areas. This system is currently under tests by the authors in order to verify the latency of the message and the applicability and accuracies obtainable in particular in dynamic applications.

  19. Cygnus Pressurized Cargo Module (PCM) Flight Inertial Load Static Tests

    NASA Astrophysics Data System (ADS)

    Murgia, Giovanni; Mancini, Simone; Palmieri, Paolo; Rutigliano, Luigi

    2012-07-01

    Cygnus PCM Flight Inertial Load Static Test campaign has been performed by Thales Alenia Space - Italy (TAS-I) to achieve the Static Qualification of its Primary Structure. A “Proto-flight Approach” has been followed (as per [1] and [2]), thus the first flight unit, the PCM0, has been tested up to qualification level (qualification/acceptance factor equivalent to 1.2 [1]). The PCM0 has been constrained to a dummy Service Module (the second member of Cygnus Spacecraft), representative in terms of interfaces provisions, and flight load conditions have been reproduced with proper forces that have been applied by means of hydraulic jacks at internal PCM secondary structure interfaces. Test load cases have been defined in order to simulate load paths and relevant stress fields associated to the worst flight load conditions by using the FE model analyses. Tests have been monitored by means of gauges and displacement transducers and results have been utilized to correlate the PCM FEM following [3] requirements.

  20. Static tests of the propulsion system. [Propfan Test Assessment program

    NASA Technical Reports Server (NTRS)

    Withers, C. C.; Bartel, H. W.; Turnberg, J. E.; Graber, E. J.

    1987-01-01

    Advanced, highly-loaded, high-speed propellers, called propfans, are promising to revolutionize the transport aircraft industry by offering a 15- to 30-percent fuel savings over the most advanced turbofans without sacrificing passenger comfort or violating community noise standards. NASA Lewis Research Center and industry have been working jointly to develop the needed propfan technology. The NASA-funded Propfan Test Assessment (PTA) Program represents a key element of this joint program. In PTA, Lockheed-Georgia, working in concert with Hamilton Standard, Rohr Industries, Gulfstream Aerospace, and Allison, is developing a propfan propulsion system which will be mounted on the left wing of a modified Gulfstream GII aircraft and flight tested to verify the in-flight characteristics of a 9-foot diameter, single-rotation propfan. The propfan, called SR-7L, was designed and fabricated by Hamilton Standard under a separate NASA contract. Prior to flight testing, the PTA propulsion system was static tested at the Rohr Brown Field facility. In this test, propulsion system operational capability was verified and data was obtained on propfan structural response, system acoustic characteristics, and system performance. This paper reports on the results of the static tests.

  1. Heterogeneous patterns enhancing static and dynamic texture classification

    NASA Astrophysics Data System (ADS)

    Rosa da Silva, Núbia; Martinez Bruno, Odemir

    2013-02-01

    Some mixtures, such as colloids like milk, blood, and gelatin, have homogeneous appearance when viewed with the naked eye, however, to observe them at the nanoscale is possible to understand the heterogeneity of its components. The same phenomenon can occur in pattern recognition in which it is possible to see heterogeneous patterns in texture images. However, current methods of texture analysis can not adequately describe such heterogeneous patterns. Common methods used by researchers analyse the image information in a global way, taking all its features in an integrated manner. Furthermore, multi-scale analysis verifies the patterns at different scales, but still preserving the homogeneous analysis. On the other hand various methods use textons to represent the texture, breaking texture down into its smallest unit. To tackle this problem, we propose a method to identify texture patterns not small as textons at distinct scales enhancing the separability among different types of texture. We find sub patterns of texture according to the scale and then group similar patterns for a more refined analysis. Tests were performed in four static texture databases and one dynamical one. Results show that our method provide better classification rate compared with conventional approaches both in static and in dynamic texture.

  2. Single-asperity friction during quasi-static sliding

    NASA Astrophysics Data System (ADS)

    Sharp, Tristan; Pastewka, Lars; Robbins, Mark

    2015-03-01

    The static friction of an asperity is investigated using atomic-scale simulations. We explore scale effects by varying the sphere radius R and the contact radius a from nanometers to micrometers. We first consider commensurate contact between bare lattices with repulsive interactions across the interface. In small contacts, all contacting atoms move coherently and the friction coefficient μ is independent of contact radius and load. In larger contacts, interfacial slip is mediated by localized dislocations, and the static friction coefficient μ ~ (Ra0/a2) 2 / 3 , where a0 is the nearest-neighbor spacing. In very large contacts μ stops decreasing and begins to increase with a, at fixed R. The results are in sharp contrast to Cattaneo-Mindlin continuum theory where μ is independent of contact size. Separate simulations are performed to connect the results to the dislocation-based models of contact-size effects due to Hurtado and Kim, and Gao, which assume adhesive interactions between surfaces and find μ ~ (a0/a)1/2. Simulations for incommensurate contacts show a transition from superlubricity for rigid contacts to a finite friction associated with the Peierls stress in very large contacts. Support from: DMR-1006805; NSF IGERT-0801471; OCI-0963185; CMMI-0923018

  3. Static investigation of several yaw vectoring concepts on nonaxisymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Mason, M. L.; Berrier, B. L.

    1985-01-01

    A test has been conducted in the static test facility of the Langley 16-Foot Transonic Tunnel to determine the flow-turning capability and the effects on nozzle internal performance of several yaw vectoring concepts. Nonaxisymmetric convergent-divergent nozzles with throat areas simulating dry and afterburning power settings and single expansion ramp nozzles with a throat area simulating a dry power setting were modified for yaw thrust vectoring. Forward-thrust and pitch-vectored nozzle configurations were tested with each yaw vectoring concept. Four basic yaw vectoring concepts were investigated on the nonaxisymmetric convergent-divergent nozzles: (1) translating sidewall; (2) downstream (of throat) flaps; (3) upstream (of throat) port/flap; and (4) powered rudder. Selected combinations of the rudder with downstream flaps or upstream port/flap were also tested. A single yaw vectoring concept, post-exit flaps, was investigated on the single expansion ramp nozzles. All testing was conducted at static (no external flow) conditions and nozzle pressure ratios varied from 2.0 up to 10.0.

  4. Engineering mechanics: statics and dynamics. [Textbook

    SciTech Connect

    Sandor, B.I.

    1983-01-01

    The purpose of this textbook is to provide engineering students with basic learning material about statics and dynamics which are fundamental engineering subjects. The chapters contain information on: an introduction to engineering mechanics; forces on particles, rigid bodies, and structures; kinetics of particles, particle systems, and rigid bodies in motion; kinematics; mechanical vibrations; and friction, work, moments of inertia, and potential energy. Each chapter contains introductory material, the development of the essential equations, worked-out example problems, homework problems, and, finally, summaries of the essential methods and equations, graphically illustrated where appropriate. (LCL)

  5. S-IC Static Test Stand

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Constructed in 1964, the S-IC Static Test Stand was designed to develop and test the first stage (S-IC) of the Saturn V launch vehicle. In the 1974 the test stand was modified to test the liquid hydrogen tank on the Space Shuttle External Tank. The facility was again modified in 1986 and its name was changed to the Advanced Engine Test Facility. These modifications were made to accommodate the Technology Test Bed engine which is a derivative of the Space Shuttle Main Engine.

  6. Mobile and static molecular disorder in liquids

    NASA Astrophysics Data System (ADS)

    Huyskens, Pierre L.

    1992-11-01

    The fraction of time during which a molecule of a pure alcohol does not undergo H-bonding, estimated from the vapor pressure, is two orders of magnitude larger than the fraction of molecules that at a given time are not bound by an H-bond to their neighbors, as deduced from IR spectroscopic data. This obviously "anti-ergodic" statement renders questionable all the thermodynamic treatments of H-bonding in liquids, which are based on the usual Boltzmann expression. This expression equates the thermodynamic probability of a system with the static probability of distribution of the various states and, as outlined by Einstein, does not hold for non-ergodic systems. As pointed out by Pais (A. Pais, Subtle is the Lord. The Science and the Life of Albert Einstein, Oxford University Press, 1982), another Boltzmann relation relates the thermodynamic probability of a state to the fraction of time during which the system is found in that state. The latter definition was used by Einstein in his treatment of the ergodic problem. Similarly, the theory of the thermodynamics of mobile order in H-bonded liquids, of Huyskens and Siegel (P.L. Huyskens and G.G. Siegel, Bull. Soc. Chim. Belg., 97 (1988) 821), considers not the static configurations of the liquid, but the fraction of time during which an OH proton follows the oxygen atom of one or another neighboring molecules in its motion through the liquid. This coordination lowers the entropy and this reduction can be evaluated quantitatively. The present paper establishes a distinction between the static disorder, which is due to the possibility of exchange between the positions of the molecules and exists in mixed crystals, and the mobile disorder, which is due to the enlargement of the domain available for the motions of a given molecule, provoked by the mixing of two real gases. The mixing of two liquids allows an exchange in the positions, but also an expansion of the individual domains available for the motions. Thus, the

  7. Static quark potential in three flavor QCD

    SciTech Connect

    Bernard, Claude; Burch, Tom; Orginos, Kostas; Toussaint, Doug; DeGrand, Thomas A.; DeTar, Carleton; Gottlieb, Steven; Heller, Urs M.; Hetrick, James E.; Sugar, Bob

    2000-08-01

    We study the effects of dynamical quarks on the static quark potential at distances shorter than those where string breaking is expected. Quenched calculations and calculations with three flavors of dynamical quarks are done on sets of lattices with the lattice spacings matched within about one percent. The effect of the sea quarks on the shape of the potential is clearly visible. We investigate the consequences of these effects in a very crude model, namely solving Schroedinger's equation in the resulting potential. (c) 2000 The American Physical Society.

  8. Static Scale Conversion Weigh-In-Motion System

    SciTech Connect

    Beshears, D.L.

    2001-05-18

    followed by a fully optimized system to be developed, tested and made ready for commercialization in the FY-2002 timeframe. A further objective of this program will be to bring several DOD organizations together for a common goal, leverage private industry resources and funds, and utilize Tennessee Department of Transportation facilities and support personnel to augment the cost of testing and evaluation activities performed by ORNL. The specific objectives of this initial program were to: (1) Define, develop, and fabricate the initial building block system hardware and software, (2) Demonstrate system principles and basic functionality while interfacing with representative static scales and thereby, validate the static scale conversion concept, (3) Survey up to eight prominent Army and Air Force power projection bases for type and design of the existing static scales and determine if the scales can be converted to a SSC-WIM system, and (4) Document these efforts and findings in a final report and provide cost, schedule, and performance planning data for a follow-on production program.

  9. Static and Dynamic Criticality: Are They Different?

    SciTech Connect

    Cullen, D E; Clouse, C J; Procassini, R; Little, R C

    2003-12-12

    Let us start by stating that this paper does not contain anything new. It only contains material that has been known for decades, but which is periodically forgotten. As such this paper is intended merely to refresh people's memories. We will also mention that this paper is an example of the occasional discrepancy between textbook methodologies and real world applications, in the sense that the conclusions reached here contradict what it says in most textbooks, i.e., most textbooks incorrectly interpret the methods presented here, particularly with respect to the use of importance sampling to maintain population control. This paper is not intended as a general tutorial on criticality calculations. It is intended only to clarify the accuracy of various methods for solving criticality problems, such as a true time dependent dynamic calculation, versus an alpha or K static calculation. In particular, we address the long standing controversy between users of the TART code [1] with the dynamic method, and users of the MCNP code [2] with the alpha static method. In this paper we will prove which methods are accurate and inaccurate.

  10. On static Poincaré-Einstein metrics

    NASA Astrophysics Data System (ADS)

    Galloway, Gregory J.; Woolgar, Eric

    2015-06-01

    The classification of solutions of the static vacuum Einstein equations, on a given closed manifold or an asymptotically flat one, is a long-standing and much-studied problem. Solutions are characterized by a complete Riemannian n-manifold ( M, g) and a positive function N, called the lapse. We study this problem on Asymptotically Poincaré-Einstein n-manifolds, n ≥ 3, when the conformal boundary-at-infinity is either a round sphere, a flat torus or smooth quotient thereof, or a compact hyperbolic manifold. Such manifolds have well-defined Wang mass, and are time-symmetric slices of static, vacuum, asymptotically anti-de Sitter spacetimes. By integrating a mildly generalized form of an identity used by Lindblom, Shen, Wang, and others, we give a mass formula for such manifolds. There are no solutions with positive mass. In consequence, we observe that either the lapse is trivial and ( M, g) is Poincaré-Einstein or the Wang mass is negative, as in the case of time symmetric slices of the AdS soliton. As an application, we use the mass formula to compute the renormalized volume of the warped product ( X, γ) ≃ ( M 3 , g) × N 2 ( S 1 , dt 2).

  11. Static network structure can stabilize human cooperation.

    PubMed

    Rand, David G; Nowak, Martin A; Fowler, James H; Christakis, Nicholas A

    2014-12-01

    The evolution of cooperation in network-structured populations has been a major focus of theoretical work in recent years. When players are embedded in fixed networks, cooperators are more likely to interact with, and benefit from, other cooperators. In theory, this clustering can foster cooperation on fixed networks under certain circumstances. Laboratory experiments with humans, however, have thus far found no evidence that fixed network structure actually promotes cooperation. Here, we provide such evidence and help to explain why others failed to find it. First, we show that static networks can lead to a stable high level of cooperation, outperforming well-mixed populations. We then systematically vary the benefit that cooperating provides to one's neighbors relative to the cost required to cooperate (b/c), as well as the average number of neighbors in the network (k). When b/c > k, we observe high and stable levels of cooperation. Conversely, when b/c ≤ k or players are randomly shuffled, cooperation decays. Our results are consistent with a quantitative evolutionary game theoretic prediction for when cooperation should succeed on networks and, for the first time to our knowledge, provide an experimental demonstration of the power of static network structure for stabilizing human cooperation. PMID:25404308

  12. Static imaging of a rotating object

    NASA Astrophysics Data System (ADS)

    Ogura, Yukiko; Sekihara, Kensuke

    A new method for obtaining a static image of a rotating object has been studied. This method requires only one static field gradient in a fixed direction. The reconstruction technique proposed by Macovski can be applied to this imaging method. The nth sideband in the discrete spectrum obtained using the proposed method represents the magnetization with a point spread function which is equal to Bessel function Jn2 This point spread function can be modified to an appropriate shape using J2 synthesis. To obtain acceptable image quality, all positive-order sidebands should be employed when reconstructing with J2 synthesis. The number of sidebands required increases as spatial resolution improves. The area values of the sidebands rather than their peak values should be used in reconstruction to avoid the influence of main field nonuniformity and field gradient nonlinearity in the proposed method. Experiments show that the rotation frequency has to be set large enough to avoid overlapping the envelopes of neighboring sidebands in the discrete spectrum.

  13. Effect of modified hold-relax stretching and static stretching on hamstring muscle flexibility

    PubMed Central

    Ahmed, Hashim; Iqbal, Amir; Anwer, Shahnawaz; Alghadir, Ahmad

    2015-01-01

    [Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control groups. The modified hold-relax stretching group performed 7 seconds of isometric contraction and then relaxed for 5 seconds, and this was repeated five times daily for five consecutive days. The static stretching group received 10 minutes of static stretching with the help of a pulley and weight system for five consecutive days. The control group received only moist heat for 20 minutes for five consecutive days. A baseline reading of passive knee extension (PKE) was taken prior to the intervention; rest measurements were taken immediate post intervention on day 1, day 3, day 5, and after a 1 week follow-up, i.e., at the 12th day. [Results] On comparing the baseline readings of passive knee extension (PKE), there was no difference noted between the three groups. On comparing the posttest readings on day 5 between the 3 groups, a significant difference was noted. However, post hoc analysis revealed an insignificant difference between the modified hold-relax stretching and static stretching groups. There was a significant difference between the static stretching and control groups and between the modified hold-relax stretching and control groups. [Conclusion] The results of this study indicate that both the modified hold-relax stretching technique and static stretching are equally effective, as there was no significant difference in improving the hamstring muscle flexibility between the two groups. PMID:25729210

  14. Static vs dynamic settlement and adhesion of diatoms to ship hull coatings.

    PubMed

    Zargiel, Kelli A; Swain, Geoffrey W

    2014-01-01

    Many experiments utilize static immersion tests to evaluate the performance of ship hull coatings. These provide valuable data; however, they do not accurately represent the conditions both the hull and fouling organisms encounter while a ship is underway. This study investigated the effect of static and dynamic immersion on the adhesion and settlement of diatoms to one antifouling coating (BRA 640), four fouling-release coatings (Intersleek(®) 700, Intersleek(®) 900, Hempasil X3, and Dow Corning 3140) and one standard surface (Intergard(®) 240 Epoxy). Differences in community composition were observed between the static and dynamic treatments. Achnanthes longipes was present on all coatings under static immersion, but was not present under dynamic immersion. This was also found for diatoms in the genera Bacillaria and Gyrosigma. Melosira moniformis was the only diatom present under dynamic conditions, but not static conditions. Several common fouling diatom genera were present on panels regardless of treatment: Amphora, Cocconeis, Entomoneis Cylindrotheca, Licmophora, Navicula, Nitzschia, Plagiotropis, and Synedra. Biofilm adhesion, diatom abundance and diatom diversity were found to be significantly different between static and dynamic treatments; however, the difference was dependent on coating and sampling date. Several coatings (Epoxy, DC 3140 and IS 700) had significantly higher biofilm adhesion on dynamically treated panels on at least one of the four sampling dates, while all coatings had significantly higher diatom abundance on at least one sampling date. Diversity was significantly greater on static panels than dynamic panels for Epoxy, IS 700 and HX3 at least once during the sampling period. The results demonstrate how hydrodynamic stress will significantly influence the microfouling community. Dynamic immersion testing is required to fully understand how antifouling surfaces will respond to biofilm formation when subjected to the stresses experienced

  15. Quasi-static vapor pressure measurements on reactive systems in inert atmosphere box

    NASA Technical Reports Server (NTRS)

    Fischer, A. K.

    1968-01-01

    Apparatus makes vapor pressure measurements on air-sensitive systems in an inert atmosphere glove box. Once the apparatus is loaded with the sample and all connections made, all measuring operations may be performed outside the box. The apparatus is a single-tube adaptation of the double-tube quasi-static technique.

  16. Static Balance: A Comparative Study of Primary Age Boys and Girls.

    ERIC Educational Resources Information Center

    DiNucci, James M.

    The ability to attain and maintain a body position or balance is considered important in learning and performing motor skills. Static balance is defined as balance in which the body maintains equilibrium for one position; dynamic balance is described as maintaining equilibrium while the body is in motion or changing from one balanced position to…

  17. Recognition of Facial Emotional Expressions from Moving and Static Displays by Individuals with Mental Retardation.

    ERIC Educational Resources Information Center

    Harwood, Natalie K.; Hall, Laura J.; Shinkfield, Alison J.

    1999-01-01

    Adults (N=24) with and without mental retardation were shown moving and static videotaped and photographic displays of posed emotional expressions. Individuals with mental retardation were significantly poorer at identifying anger, fear, disgust, and surprise. Both groups performed significantly better on the moving as opposed to the static…

  18. Mapping of Reservoir Properties and Facies Through Integration of Static and Dynamic Data

    SciTech Connect

    Reynolds, Albert C.; Oliver, Dean S.; Zhang, Fengjun; Dong, Yannong; Skjervheim, Jan Arild; Liu, Ning

    2003-03-10

    The goal of this project was to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem was necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management.

  19. Relationships of Muscular Endurance Among Specific Muscle Groups for Continuous and Intermittent Static Contractions.

    ERIC Educational Resources Information Center

    Hoshizaki, Thomas B.; Massey, B. H.

    1986-01-01

    The static contraction endurance characteristics of five muscle groups were investigated in 38 normal, health, college-aged men. Four parameters of continuous and intermittent contractions were examined. Results support the hypothesis that endurance is unique to each muscle group and specific to the task performed. (Author/MT)

  20. Mapping of Reservoir Properties and Facies Through Integration of Static and Dynamic Data

    SciTech Connect

    Oliver, Dean S.; Reynolds, Albert C.; Zhang, Fengjun; Li, Ruijian; Abacioglu, Yafes; Dong, Yannong

    2002-03-05

    The goal of this project was to develop computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Solution of this problem is necessary for the quantification of uncertainty in future reservoir performance predictions and for the optimization of reservoir management.

  1. A Comparison of Static Picture Prompting and Video Prompting Simulation Strategies Using Group Instructional Procedures

    ERIC Educational Resources Information Center

    Cihak, David; Alberto, Paul A.; Taber-Doughty, Teresa; Gama, Robert I.

    2006-01-01

    Two groups of three students with moderate mental retardation were instructed using group procedures to compare static picture and video prompting simulation strategies. An alternating treatments design was used to compare individual student task acquisition and maintenance performances of purchasing and banking skills. The results indicated that…

  2. 12-Month-Old Infants' Perception of Attention Direction in Static Video Images

    ERIC Educational Resources Information Center

    von Hofsten, Claes; Dahlstrom, Emma; Fredriksson, Ylva

    2005-01-01

    Twelve-month-old infants' ability to perceive gaze direction in static video images was investigated. The images showed a woman who performed attention-directing actions by looking or pointing toward 1 of 4 objects positioned in front of her (2 on each side). When the model just pointed at the objects, she looked straight ahead, and when she just…

  3. Degradation of learned skills. Static practice effectiveness for visual approach and landing skill retention

    NASA Technical Reports Server (NTRS)

    Sitterley, T. E.

    1974-01-01

    The effectivess of an improved static retraining method was evaluated for a simulated space vehicle approach and landing under instrument and visual flight conditions. Experienced pilots were trained and then tested after 4 months without flying to compare their performance using the improved method with three methods previously evaluated. Use of the improved static retraining method resulted in no practical or significant skill degradation and was found to be even more effective than methods using a dynamic presentation of visual cues. The results suggested that properly structured open loop methods of flight control task retraining are feasible.

  4. Description of a pressure measurement technique for obtaining surface static pressures of a radial turbine

    NASA Astrophysics Data System (ADS)

    Dicicco, L. D.; Nowlin, Brent C.; Tirres, Lizet

    1992-07-01

    The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

  5. Description of a pressure measurement technique for obtaining surface static pressures of a radial turbine

    NASA Astrophysics Data System (ADS)

    Dicicco, L. Danielle; Nowlin, Brent C.; Tirres, Lizet

    1992-02-01

    The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

  6. Description of a Pressure Measurement Technique for Obtaining Surface Static Pressures of a Radial Turbine

    NASA Technical Reports Server (NTRS)

    Dicicco, L. Danielle; Nowlin, Brent C.; Tirres, Lizet

    1992-01-01

    The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

  7. Description of a pressure measurement technique for obtaining surface static pressures of a radial turbine

    NASA Technical Reports Server (NTRS)

    Dicicco, L. D.; Nowlin, Brent C.; Tirres, Lizet

    1992-01-01

    The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

  8. Development of a low risk augmentation system for an energy efficient transport having relaxed static stability

    NASA Technical Reports Server (NTRS)

    Sizlo, T. R.; Berg, R. A.; Gilles, D. L.

    1979-01-01

    An augmentation system for a 230 passenger, twin engine aircraft designed with a relaxation of conventional longitudinal static stability was developed. The design criteria are established and candidate augmentation system control laws and hardware architectures are formulated and evaluated with respect to reliability, flying qualities, and flight path tracking performance. The selected systems are shown to satisfy the interpreted regulatory safety and reliability requirements while maintaining the present DC 10 (study baseline) level of maintainability and reliability for the total flight control system. The impact of certification of the relaxed static stability augmentation concept is also estimated with regard to affected federal regulations, system validation plan, and typical development/installation costs.

  9. Size effect on the static behavior of electrostatically actuated microbeams

    NASA Astrophysics Data System (ADS)

    Yin, Li; Qian, Qin; Wang, Lin

    2011-06-01

    We present a new analytical model for electrostatically actuatedmicrobeams to explore the size effect by using the modified couple stress theory and the minimum total potential energy principle. A material length scale parameter is introduced to represent the size-dependent characteristics of microbeams. This model also accounts for the nonlinearities associated with the mid-plane stretching force and the electrostatical force. Numerical analysis for microbeams with clamped-clamped and cantilevered conditions has been performed. It is found that the intensity of size effect is closely associated with the thickness of the microbeam, and smaller beam thickness displays stronger size effect and hence yields smaller deflection and larger pull-in voltage. When the beam thickness is comparable to the material length scale parameter, the size effect is significant and the present theoretical model including the material length scale parameter is adequate for predicting the static behavior of microbeam-based MEMS.

  10. Development of a high temperature static strain sensor

    NASA Astrophysics Data System (ADS)

    Hulse, Charles O.; Bailey, Richard S.; Grant, Howard P.

    1986-10-01

    The goal of this program is to develop an electrical resistance strain gage system which will accurately measure the static strains of superalloy blades and vanes in gas turbine engines running on a test stand. Accurate knowledge of these strains is essential to reaching the goals of the HOST program in the selection and experimental verification of the various theoretical models developed to understand and improve the performance of these engines. The specific objective is to develop a complete system capable of making strain measurements of up to + or - 10 percent of full scale during a 50 hour period at temperatures as high as 1250 K. In addition to survival and stability, attaining a low temperature coefficient of resistance, of the order of 20 ppm/K or less, was a major goal. This requirement arises from the presently unavoidable uncertainties in measurement of the exact temperatures inside gas turbines for use in making corrections for apparent strain due to temperature.

  11. Static and dynamic high pressure experiments on cerium

    SciTech Connect

    Jensen, Brian J; Velisavljevic, Nenad; Cherne, Frank J; Stevens, Gerald; Tschauner, Oliver

    2011-01-25

    There is a scientific need to obtain dynamic data to develop and validate multi phase equation-of-state (EOS) models for metals. Experiments are needed to examine the relevant pure phases, to locate phase boundaries and the associated transition kinetics, and other material properties such as strength. Cerium is an ideal material for such work because it exhibits a complex multiphase diagram at relatively moderate pressures readily accessible using standard shock wave methods. In the current work, shock wave (dynamic) and diamond anvil cell (static) experiments were performed to examine the high pressure, low temperature region of the phase diagram to obtain EOS data and to search for the {alpha}-{var_epsilon} boundary. Past work examining the shock-melt transition and the low-pressure {gamma}-{alpha} transition will be presented in brief followed by details of recent results obtained from DAC and double-shock experiments.

  12. Development of a high temperature static strain sensor

    NASA Technical Reports Server (NTRS)

    Hulse, Charles O.; Bailey, Richard S.; Grant, Howard P.

    1986-01-01

    The goal of this program is to develop an electrical resistance strain gage system which will accurately measure the static strains of superalloy blades and vanes in gas turbine engines running on a test stand. Accurate knowledge of these strains is essential to reaching the goals of the HOST program in the selection and experimental verification of the various theoretical models developed to understand and improve the performance of these engines. The specific objective is to develop a complete system capable of making strain measurements of up to + or - 10 percent of full scale during a 50 hour period at temperatures as high as 1250 K. In addition to survival and stability, attaining a low temperature coefficient of resistance, of the order of 20 ppm/K or less, was a major goal. This requirement arises from the presently unavoidable uncertainties in measurement of the exact temperatures inside gas turbines for use in making corrections for apparent strain due to temperature.

  13. Materials and techniques for spacecraft static charge control 2

    NASA Technical Reports Server (NTRS)

    Schmidt, R. E.; Eagles, A. E.

    1979-01-01

    Results of exploratory development on the design, fabrication and testing of transparent conductive coatings, conductive bulk materials and grounding techniques for application to high resistivity spacecraft dielectric materials to obtain control of static charge buildup are presented. Deposition techniques for application of indium oxide, indium/tin oxide and other metal oxide films on Kapton, FEP Teflon, OSR and solar cell coverglasses discussed include RF and Magnetron sputtering and vapor deposition. Development, fabrication and testing of conductive glass tiles for OSR and solar cell coverglass applications is discussed. Several grounding techniques for rapid charge dissipation from the conductively coated polymer and glass dielectrics which were developed and tested in thermal cycled and electron plasma environments are described. The optical and electrical characterization and aging effects of these coatings, bulk materials and grounding techniques are reviewed as they apply to the performance of their design functions in a geosynchronous orbit environment.

  14. Demonstration of relaxed static stability on a commercial transport

    NASA Technical Reports Server (NTRS)

    Rising, J. J.; Davis, W. J.; Willey, C. S.; Cokeley, R. C.

    1984-01-01

    Increasing jet aircraft fuel costs from 25 percent to nearly 60 percent of the aircraft direct operating costs have led to a heavy emphasis on the development of transport aircraft with significantly improved aerodynamic performance. The application of the concept of relaxed static stability (RSS) and the utilization of an active control stability augmentation system make it possible to design an aircraft with reduced aerodynamic trim drag due to a farther-aft cg balance. Reduced aerodynamic parasite drag and lower structural weight due to a smaller horizontal tail surface can also be obtained. The application of RSS has been studied under a NASA-sponsored program to determine ways of improving the energy efficiency in current and future transport aircraft. Attention is given to a near-term pitch active control system, an advanced pitch active control system, and an operational overview.

  15. New nonimaging static concentrators for bifacial photovoltaic solar cells

    NASA Astrophysics Data System (ADS)

    Benitez, Pablo; Hernandez, Maikel; Mohedano Arroyo, Ruben; Minano, Juan C.; Munoz, Fernando

    1999-10-01

    Two new static nonimaging designs for bifacial solar cells are presented. These concentrators have been obtained with the Simultaneous Multiple Surface design method of Nonimaging Optics. The main characteristics of these concentrators are: (1) high compactness, (2) linear symmetry (in order to be made by low cost extrusion), (3) performance close to the thermodynamic limit, and (4) a non-shading sizable gap between at least one of the cell edges and the optically active surfaces. This last feature is interesting because this gap can be used to allocate the interconnections between cells, with no additional optical losses. As an example of the results, one design for an acceptable angle of +/- 30 degrees gets a geometrical concentration of 5.5X, with an average thickness to entry aperture width ratio of 0.24. The 3D ray-tracing analysis of the concentrators is also presented.

  16. Biomagnetic localization from transient quasi-static events

    SciTech Connect

    Mosher, J.C.; Leahy, R.M.; Lewis, P.S. University of Southern California, Los Angeles, CA . Signal and Image Processing Inst.)

    1993-01-01

    Sensory stimuli, such as auditory, visual, or somatosensory, evoke neural responses in very localized regions of the brain. A SQUID biomagnetometer can measure the very weak fields that are generated outside of the head by this response. A simple source and head model of current dipoles inside a conducting sphere is typically used to interpret these magnetic field measurements or magnetoencephalogram (MEG). Locating dipole sources using data recorded from an array of biomagnetic sensors is distinguished from conventional array source localization techniques by the quasi-static transient nature of the data. Here, the basic MEG model is reviewed, then a localization example is given to motivate the need for partitioning the data to improve estimator performance. Tune-eigenspectrum analysis is introduced as a means of partitioning and interpreting spatio-temporal biomagnetic data. Examples using both simulated and somatosensory data are presented.

  17. Biomagnetic localization from transient quasi-static events

    SciTech Connect

    Mosher, J.C.; Leahy, R.M.; Lewis, P.S. |

    1993-02-01

    Sensory stimuli, such as auditory, visual, or somatosensory, evoke neural responses in very localized regions of the brain. A SQUID biomagnetometer can measure the very weak fields that are generated outside of the head by this response. A simple source and head model of current dipoles inside a conducting sphere is typically used to interpret these magnetic field measurements or magnetoencephalogram (MEG). Locating dipole sources using data recorded from an array of biomagnetic sensors is distinguished from conventional array source localization techniques by the quasi-static transient nature of the data. Here, the basic MEG model is reviewed, then a localization example is given to motivate the need for partitioning the data to improve estimator performance. Tune-eigenspectrum analysis is introduced as a means of partitioning and interpreting spatio-temporal biomagnetic data. Examples using both simulated and somatosensory data are presented.

  18. Static Fatigue of Optical Fibers in Bending

    NASA Astrophysics Data System (ADS)

    Roberts, D.; Cuellar, E.; Middleman, L.; Zucker, J.

    1987-02-01

    While delayed fracture, or static fatigue, of optical fibers is well known, it is not well understood, and the prediction of the time to failure under a given set of conditions can be problematic. Unlike short term fracture, which is quite well understood and quantified in terms of the theory of linear elastic fracture mechanics, the long term strength remains empirical. The goal of this study is to determine the design criteria for optical fibers subjected to long term applied mechanical loads. One difficulty in making lifetime predictions, as pointed out by Matthewson (Reference 1) and others, is that predictions made from data taken in tension and in bending do not agree. Another difficulty is the statistical nature of the fracture of glass. In making lifetime predictions it becomes important therefore that one (a) have ample data for statistical analysis and (b) have data for the loading configuration of interest. This is the purpose of our work. Since there is less data available in bending, and since several applications (such as wiring in aircraft and missiles) require bending, the data are taken in that configuration. The most significant finding in our work so far is the very large difference in static fatigue behavior between buffer coatings. Chandan and Kalish (Reference 2) and others have reported static fatigue curves, log (time to failure) versus log (applied stress), which are not linear, but rather bimodal. Our study confirms this result, but so far only for acrylate coated fibers. Silicone coated fibers show unimodal behavior. That is, the log (time to failure) versus log (applied stress) curve is linear, at least on the time scale studied so far. Data for acrylate coated fibers at 80°C in water are linear only for time scales of about one day, where a pronounced "knee" is observed. Data for silicone coated fibers under the same conditions are linear up to at least 6 months. Longer time scale tests and tests on fibers with other buffer materials

  19. Static Analysis Tools, a Practical Approach for Safety-Critical Software Verification

    NASA Astrophysics Data System (ADS)

    Lopes, R.; Vicente, D.; Silva, N.

    2009-05-01

    Static code analysis tools available today range from Lintbased syntax parsers to standards' compliance checkers to tools using more formal methods for verification. As safety critical software complexity is increasing, these tools provide a mean to ensure code quality, safety and dependability attributes. They also provide a mean to introduce further automation in code analysis activities. The features presented by static code analysis tools are particularly interesting for V&V activities. In the scope of Independent Code Verification (IVE), two different static analysis tools have been used during Code Verification activities of the LISA Pathfinder onboard software in order to assess their contribution to the efficiency of the process and quality of the results. Polyspace (The MathWorks) and FlexeLint (Gimpel) tools have been used as examples of high-budget and low-budget tools respectively. Several aspects have been addressed: effort has been categorised for closer analysis (e.g. setup and configuration time, execution time, analysis of the results, etc), reported issues have been categorised according to their type and the coverage of traditional IVE tasks by the static code analysis tools has been evaluated. Final observations have been performed by analysing the previously referred subjects, namely regarding cost effectiveness, quality of results, complementarities between the results of different static code analysis tools and relation between automated code analysis and manual code inspection.

  20. Using Static and Dynamic Visuals to Represent Chemical Change at Molecular Level

    NASA Astrophysics Data System (ADS)

    Ardac, Dilek; Akaygun, Sevil

    2005-09-01

    The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty-two eighth graders (age range 14 15 years) participated in one of the three instructional conditions (dynamic individual, dynamic whole class, and static whole class) designed to improve molecular understanding on chemical change. The results indicated significantly higher performance for students who used dynamic visuals compared with those who used static visuals. Furthermore, students who used dynamic visuals on an individual basis were more consistent in their use of molecular representations compared with students who received whole-class instruction with dynamic or static visuals. The results favour the use of dynamic visuals (preferably on an individual basis) over static visuals when presenting molecular representations. The results also imply that the effectiveness of instruction will improve if teachers challenge and question the inconsistencies and contradictions between verbal explanations and corresponding molecular representations