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Sample records for actuated propellant orientation

  1. Computational Modeling of Magnetically Actuated Propellant Orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    sufficient performance to support cryogenic propellant management tasks. In late 1992, NASA MSFC began a new investigation in this technology commencing with the design of the Magnetically-Actuated Propellant Orientation (MAPO) experiment. A mixture of ferrofluid and water is used to simulate the paramagnetic properties of LOX and the experiment is being flown on the KC-135 aircraft to provide a reduced gravity environment. The influence of a 0.4 Tesla ring magnet on flow into and out of a subscale Plexiglas tank is being recorded on video tape. The most efficient approach to evaluating the feasibility of MAPO is to compliment the experimental program with development of a computational tool to model the process of interest. The goal of the present research is to develop such a tool. Once confidence in its fidelity is established by comparison to data from the MAPO experiment, it can be used to assist in the design of future experiments and to study the parameter space of the process. Ultimately, it is hoped that the computational model can serve as a design tool for full-scale spacecraft applications.

  2. Computational modeling of magnetically actuated propellant orientation

    NASA Technical Reports Server (NTRS)

    Hochstein, John I.

    1996-01-01

    Unlike terrestrial applications where gravity positions liquid at the 'bottom' of the tank, the location of liquid propellant in spacecraft tanks is uncertain unless specific actions are taken or special features are built into the tank. Some mission events require knowledge of liquid position prior to a particular action: liquid must be positioned over the tank outlet prior to starting the main engines and must be moved away from the tank vent before vapor can be released overboard to reduce pressure. It may also be desirable to positively position liquid to improve propulsion system performance: moving liquid away from the tank walls will dramatically decrease the rate of heat transfer to the propellant, suppressing the boil-off rate, thereby reducing overall mission propellant requirements. The process of moving propellant to a desired position is referred to as propellant orientation or reorientation. Several techniques have been developed to positively position propellant in spacecraft tanks and each technique imposes additional requirements on vehicle design. Propulsive reorientation relies on small auxiliary thrusters to accelerate the tank. The inertia of the liquid causes it to collect in the aft-end of the tank if the acceleration is forward. This technique requires that additional thrusters be added to the vehicle, that additional propellant be carried in the vehicle, and that an additional operational maneuver be executed. Another technique uses Liquid Acquisition Devices (LAD's) to positively position propellants. These devices rely on surface tension to hold the liquid within special geometries (i.e. vanes, wire-mesh channels, start-baskets). While avoiding some of the penalties of propulsive orientation, this technique requires the addition of complicated hardware inside the propellant tank and performance for long duration missions is uncertain. The subject of the present research is an alternate technique for positively positioning liquid within

  3. Magnetically Actuated Propellant Orientation, Controlling Fluids in a Low-Gravity Environment

    NASA Technical Reports Server (NTRS)

    Martin, James J.; Holt, James B.

    2000-01-01

    Cryogenic fluid management (CFM) is a technology area common to virtually every space transportation propulsion concept envisioned. Storage, supply, transfer and handling of sub-critical cryogenic fluids are basic capabilities that have long been needed by multiple programs and the need is expected to continue in the future. The use of magnetic fields provides another method, which could replace or augment current/traditional approaches, potentially simplifying vehicle operational constraints. The magnetically actuated propellant orientation (MAPO) program effort focused on the use of magnetic fields to control fluid motion as it relates to positioning (i.e. orientation and acquisition) of a paramagnetic substance such as LO2. Current CFM state- of-the-art systems used to control and acquire propellant in low gravity environments rely on liquid surface tension devices which employ vanes, fine screen mesh channels and baskets. These devices trap and direct propellant to areas where it's needed and have been used routinely with storable (non-cryogenic) propellants. However, almost no data exists r,egarding their operation in cryogenics and the use of such devices confronts designers with a multitude of significant technology issues. Typical problems include a sensitivity to screen dry out (due to thermal loads and pressurant gas) and momentary adverse accelerations (generated from either internal or external sources). Any of these problems can potentially cause the acquisition systems to ingest or develop vapor and fail. The use of lightweight high field strength magnets may offer a valuable means of augmenting traditional systems potentially mitigating or at least easing operational requirements. Two potential uses of magnetic fields include: 1) strategically positioning magnets to keep vent ports clear of liquid (enabling low G vented fill operations), and 2) placing magnets in the center or around the walls of the tank to create an insulating vapor pocket (between

  4. Propeller pitch change actuation system

    SciTech Connect

    Kusiak, E.H.

    1988-06-28

    An apparatus is described for adjusting the pitch of a variable pitch propeller blade characterized by: an actuator for setting the pitch of the propeller blade the actuator having; a rotatable screw for setting propeller pitch, a nut mounted for longitudinal motion along the screw as the screw is rotated, means for connecting the nut to the propeller blade to adjust the pitch of the propeller blade as the screw rotates, and a rotatable means mounted within the nut for locking the nut against longitudinal motion if the rotatable means is not rotating with the longitudinal motion of the nut and for allowing the nut to move longitudinally if the rotatable means is rotating with the longitudinal motion of the nut.

  5. Electromechanical propellant control system actuator

    NASA Technical Reports Server (NTRS)

    Myers, W. Neill; Weir, Rae Ann

    1990-01-01

    New control mechanism technologies are currently being sought to provide alternatives to hydraulic actuation systems. The Propulsion Laboratory at Marshall Space Flight Center (MSFC) is involved in the development of electromechanical actuators (EMA's) for this purpose. Through this effort, an in-house designed electromechanical propellant valve actuator has been assembled and is presently being evaluated. This evaluation will allow performance comparisons between EMA and hydraulics systems. The in-house design consists of the following hardware: a three-phase brushless motor, a harmonic drive, and an output spline which will mate with current Space Shuttle Main Engine (SSME) propellant control valves. A resolver and associated electronics supply position feedback for the EMA. System control is provided by a solid-state electronic controller and power supply. Frequency response testing has been performed with further testing planned as hardware and test facilities become available.

  6. Propellant-powered actuator for gas generators

    NASA Technical Reports Server (NTRS)

    Makowski, M. J.

    1972-01-01

    Hydrazine operated monopropellant generators are used for spacecraft rocket engines and propellant pressurization systems. Measured work output of monopropellant actuators compares favorably with output of squib-type actuators.

  7. 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.

  8. Propellant actuated nuclear reactor steam depressurization valve

    DOEpatents

    Ehrke, Alan C.; Knepp, John B.; Skoda, George I.

    1992-01-01

    A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

  9. Lead-Free Propellant for Propellant Actuated Devices

    NASA Technical Reports Server (NTRS)

    Goodwin, John L.

    2000-01-01

    Naval Surface Warfare Center, Indian Head Division's CAD/PAD Department has been working to remove toxic compounds from our products for about a decade. In 1992, we embarked on an effort to develop a lead-free double base propellant to replace that of a foreign sole source. At the time there were availability concerns. In 1995, the department developed a strategic proposal to include a wider range of products. Efforts included such efforts as removing lead sheathing from linear explosives and replacing lead azide and lead styphnate compounds. This paper will discuss efforts specifically related to developing non-leaded double base propellant for use in various Propellant Actuated Devices (PADs) for aircrew escape systems. The propellants can replace their leaded counterparts, mitigating lead handling, processing, or toxic exposure to the environment and personnel. This work eliminates the use of leaded compounds, replacing them with a more environmentally benign metal-organic salt. Historically double-base propellants have held an advantage over other families of energetic materials through their relative insensitivity of the burning rate to changes in temperature and pressure. This desirable ballistic effect has been obtained with the use of a lead-organic salt alone or in a physical mixture with a copper-organic salt, or more recently with a lead-copper complex. These ballistic modifiers are typically added to the double-base 'paste' prior to gelatinization on heated calendars or one type or another. The effect of constant burning rate over a pressure range is called a 'plateau' while an even more beneficial effect of decreasing burning rate with increasing pressure is termed a 'mesa.' The latter effect results in very low temperature sensitivity of the propellant burning rate. Propellants with such effects are ideal tactical rocket motor propellants. The use of lead compounds poses a concern for the environment and personnel safety due to the metal's toxic

  10. Magnetically Actuated Propellant Orientation Experiment, Controlling Fluid Motion With Magnetic Fields in a Low-Gravity Environment

    NASA Technical Reports Server (NTRS)

    Martin, J. J.; Holt, J. B.

    2000-01-01

    This report details the results of a series of fluid motion experiments to investigate the use of magnets to orient fluids in a low-gravity environment. The fluid of interest for this project was liquid oxygen (LO2) since it exhibits a paramagnetic behavior (is attracted to magnetic fields). However, due to safety and handling concerns, a water-based ferromagnetic mixture (produced by Ferrofluidics Corporation) was selected to simplify procedures. Three ferromagnetic fluid mixture strengths and a nonmagnetic water baseline were tested using three different initial fluid positions with respect to the magnet. Experiment accelerometer data were used with a modified computational fluid dynamics code termed CFX-4 (by AEA Technologies) to predict fluid motion. These predictions compared favorably with experiment video data, verifying the code's ability to predict fluid motion with and without magnetic influences. Additional predictions were generated for LO2 with the same test conditions and geometries used in the testing. Test hardware consisted of a cylindrical Plexiglas tank (6-in. bore with 10-in. length), a 6,000-G rare Earth magnet (10-in. ring), three-axis accelerometer package, and a video recorder system. All tests were conducted aboard the NASA Reduced-Gravity Workshop, a KC-135A aircraft.

  11. LAM actuated propellant flow control device

    NASA Astrophysics Data System (ADS)

    Reinicke, Robert H.; Cust, Kevin M.

    1992-02-01

    An advanced design LAM (limited angle motor) positions an integral flow control element for bi-level flow control of storable propellants. The LAM incorporates permanent magnet latching to maintain the flow control element in either the low or high flow position without continuous electrical energization. The LAM stator and rotor are fully sheathed within stainless steel. This construction method permits the LAM to control storable propellants without using dynamic seals to isolate the LAM from the propellants. All welded construction prevents external leakage. The design concept selection rationale and the computer FEA (finite element analysis) methods employed to optimize design characteristics are presented. Correlations of analyses to test results are described.

  12. Propellant-Flow-Actuated Rocket Engine Igniter

    NASA Technical Reports Server (NTRS)

    Wollen, Mark

    2013-01-01

    A rocket engine igniter has been created that uses a pneumatically driven hammer that, by specialized geometry, is induced into an oscillatory state that can be used to either repeatedly impact a piezoelectric crystal with sufficient force to generate a spark capable of initiating combustion, or can be used with any other system capable of generating a spark from direct oscillatory motion. This innovation uses the energy of flowing gaseous propellant, which by means of pressure differentials and kinetic motion, causes a hammer object to oscillate. The concept works by mass flows being induced through orifices on both sides of a cylindrical tube with one or more vent paths. As the mass flow enters the chamber, the pressure differential is caused because the hammer object is supplied with flow on one side and the other side is opened with access to the vent path. The object then crosses the vent opening and begins to slow because the pressure differential across the ball reverses due to the geometry in the tube. Eventually, the object stops because of the increasing pressure differential on the object until all of the kinetic energy has been transferred to the gas via compression. This is the point where the object reverses direction because of the pressure differential. This behavior excites a piezoelectric crystal via direct impact from the hammer object. The hammer strikes a piezoelectric crystal, then reverses direction, and the resultant high voltage created from the crystal is transferred via an electrode to a spark gap in the ignition zone, thereby providing a spark to ignite the engine. Magnets, or other retention methods, might be employed to favorably position the hammer object prior to start, but are not necessary to maintain the oscillatory behavior. Various manifestations of the igniter have been developed and tested to improve device efficiency, and some improved designs are capable of operation at gas flow rates of a fraction of a gram per second (0

  13. Propellant Flow Actuated Piezoelectric Igniter for Combustion Engines

    NASA Technical Reports Server (NTRS)

    Wollen, Mark A. (Inventor)

    2015-01-01

    A propellant flow actuated piezoelectric igniter device using one or more hammer balls retained by one or more magnets, or other retaining method, until sufficient fluid pressure is achieved to release and accelerate the hammer ball, such that it impacts a piezoelectric crystal to produce an ignition spark. Certain preferred embodiments provide a means for repetitively capturing and releasing the hammer ball after it impacts one or more piezoelectric crystals, thereby oscillating and producing multiple, repetitive ignition sparks. Furthermore, an embodiment is presented for which oscillation of the hammer ball and repetitive impact to the piezoelectric crystal is maintained without the need for a magnet or other retaining mechanism to achieve this oscillating impact process.

  14. Study of hydraulic actuation system for Space Shuttle main engine propellant valves

    NASA Technical Reports Server (NTRS)

    Ewel, Bob (Editor)

    1993-01-01

    Recent performance concerns involving the Space Shuttle Main Engine Propellant Valve Actuator assemblies prompted the NASA Marshall Space Flight Center to request an independent design assessment. Moog Inc. responded to this request and received a study contract with objectives of increasing valve reliability, decreasing maintenance costs while preserving the existing design interfaces. The results of the Propellant Valve Actuation System review focus on contamination control and the bypass valve design. Three proof of concept bypass valves employing design changes were built and successfully tested. Test results are presented.

  15. The triathlon of magnetic actuation: Rolling, propelling, swimming with a single magnetic material

    PubMed Central

    Vach, Peter J.; Faivre, Damien

    2015-01-01

    Magnetic actuation of microscopic devices in a liquid environment has been achieved in various ways, which can be grouped into rolling, propelling and swimming. Previous actuators were designed with a focus on one particular type of magnetic actuation. We have shown earlier that efficient magnetic propellers can be selected from randomly shaped magnetic nanostructures synthesized in solution. Here we show that these synthesized nanostructures can be used for all three types of magnetic actuation. Whereas it might not be surprising that single structures can roll in addition to propelling, swimming is unexpectedly also observed using the same material. In this case, however, the magnetically guided self-assembly of several individual particles into chain-like structures is necessary to obtain swimmers, since individual rigid nanostructures cannot swim. Interestingly, the direction of the swimming motion is not necessarily parallel to the long axis of the chain-like assembly, a finding that had been theoretically expected but experimentally not observed so far. Our findings show that the range of structures that can be effectively actuated by external magnetic fields is much broader than assumed until now. This could open up new opportunities for the design of magnetically actuated devices. PMID:25791721

  16. The triathlon of magnetic actuation: Rolling, propelling, swimming with a single magnetic material

    NASA Astrophysics Data System (ADS)

    Vach, Peter J.; Faivre, Damien

    2015-03-01

    Magnetic actuation of microscopic devices in a liquid environment has been achieved in various ways, which can be grouped into rolling, propelling and swimming. Previous actuators were designed with a focus on one particular type of magnetic actuation. We have shown earlier that efficient magnetic propellers can be selected from randomly shaped magnetic nanostructures synthesized in solution. Here we show that these synthesized nanostructures can be used for all three types of magnetic actuation. Whereas it might not be surprising that single structures can roll in addition to propelling, swimming is unexpectedly also observed using the same material. In this case, however, the magnetically guided self-assembly of several individual particles into chain-like structures is necessary to obtain swimmers, since individual rigid nanostructures cannot swim. Interestingly, the direction of the swimming motion is not necessarily parallel to the long axis of the chain-like assembly, a finding that had been theoretically expected but experimentally not observed so far. Our findings show that the range of structures that can be effectively actuated by external magnetic fields is much broader than assumed until now. This could open up new opportunities for the design of magnetically actuated devices.

  17. The triathlon of magnetic actuation: rolling, propelling, swimming with a single magnetic material.

    PubMed

    Vach, Peter J; Faivre, Damien

    2015-03-20

    Magnetic actuation of microscopic devices in a liquid environment has been achieved in various ways, which can be grouped into rolling, propelling and swimming. Previous actuators were designed with a focus on one particular type of magnetic actuation. We have shown earlier that efficient magnetic propellers can be selected from randomly shaped magnetic nanostructures synthesized in solution. Here we show that these synthesized nanostructures can be used for all three types of magnetic actuation. Whereas it might not be surprising that single structures can roll in addition to propelling, swimming is unexpectedly also observed using the same material. In this case, however, the magnetically guided self-assembly of several individual particles into chain-like structures is necessary to obtain swimmers, since individual rigid nanostructures cannot swim. Interestingly, the direction of the swimming motion is not necessarily parallel to the long axis of the chain-like assembly, a finding that had been theoretically expected but experimentally not observed so far. Our findings show that the range of structures that can be effectively actuated by external magnetic fields is much broader than assumed until now. This could open up new opportunities for the design of magnetically actuated devices.

  18. Mechanical actuators at the nanoscale: molecular propellers, paddles and wheels

    NASA Astrophysics Data System (ADS)

    Vukovic, Lela; Wang, Boyang; Kral, Petr

    2010-03-01

    We model by molecular dynamics simulations nanosystems that could realize mechanical action in nanofluidics. First, we study molecular propellers formed by carbon nanotube rotors with attached aromatic blades that can pump liquids with efficiency dependent on the chemistry of the liquid-blade interface [1]. Next, we investigate nanorods with photoactive surfaces that can roll on water when driven by light [2]. Their rolling motion is realized when chromophores attached to their surfaces become anisotropically polarized by light and attracted to water. Finally, we examine nanoscale pumping induced by deformable nanoscale blades [3]. We show that the length, polarity, frequency and amplitude of oscillations of the nanoblades control their efficiency of water pumping.[4pt] [1] B. Wang and P. Kr'al, . Rev. Lett. 98, 266102 (2007).[0pt] [2] L. Vukovic and P. Kr'al, submitted.[0pt] [3] L. Vukovic, D. Astumian and P. Kr'al, in preparation.

  19. Development of the MC3462A pyrotechnic - propellant actuated reefing line cutter

    SciTech Connect

    Craig, J.R.

    1982-06-01

    A pyrotechnic-propellant actuated reefing line cutter was developed to sever a 60 kN loaded Kevlar parachute reefing line cord. Dereefing occurs after a time interval of approximately 0.875 second which is provided by an electronic timer module that is an integral part of the cutter. Other design features include a hermetically sealed actuator which is threaded and O-ring sealed into the body, a stainless steel solid cylindrical cutter blade having an attached elastomer obturator that provides a reliable dynamic gas seal throughout the blade stroke and teflon inserts having a semi-circular configuration which are used to center and shroud the reefing line of the design. Variation in the average function time for the cutter is less than 4% at temperature extremes of -55/sup 0/C and 80/sup 0/C. Average depth of penetration of the blade into the aluminum anvil of the cutter is 2 mm.

  20. Nanorobots: the ultimate wireless self-propelled sensing and actuating devices.

    PubMed

    Sánchez, Samuel; Pumera, Martin

    2009-09-01

    Natural motor proteins, "bionanorobots," have inspired researchers to develop artificial nanomachines (nanorobots) able to move autonomously by the conversion of chemical to mechanical energy. Such artificial nanorobots are self-propelled by the electrochemical decomposition of the fuel (up to now, hydrogen peroxide). Several approaches have been developed to provide nanorobots with some functionality, such as for controlling their movement, increasing their power output, or transporting different cargo. In this Focus Review we will discuss the recent advances in nanorobots based on metallic nanowires, which can sense, deliver, and actuate in complex environments, looking towards real applications in the not-too-distant future.

  1. Design-oriented aeroservoelastic optimization of strain-actuated aircraft

    NASA Astrophysics Data System (ADS)

    Jackson, Timothy W.

    An integrated design-oriented aeroservoelastic optimization capability for strain-actuated aircraft is presented. This capability is called SMART and it encompasses a suite of computer applications created for conceptual and preliminary design of aircraft augmented with "smart" actuation technologies. The SMART suite of applications includes: (1) a dedicated pre-processor for vehicle geometry, material, actuator, mechanism, and sensor layout; (2) a dedicated finite element automesher for conventional and strain-actuated flight vehicles; (3) integration of structural dynamics with a state of the art commercial unsteady aerodynamics code (ZAERO) via automated pre- and post-processors; (4) a database architecture for analyzing multiple designs and flight conditions; and (5) automated open- and closed-loop aeroservoelastic (ASE) model preparation. The analysis techniques used as the basis for SMART are suitable (within the range of application of linear theory) for modeling real flight vehicles with real large-scale structural, aerodynamic, and control systems. These techniques include: (6) dedicated linear finite element infrastructure for modeling conventional and strain-actuated (temperature and voltage induced) flight structures; (7) dedicated static and dynamic finite element solvers; (8) state space stability analysis for coupled aeroservoelastic systems; (9) computational tools for LQR controller design; and (10) analysis tools for the calculation of random response of linear systems to random inputs. SMART can compute: (11) static aeroelastic deformations and stresses in trimmed maneuvering elastic airplanes; (12) open-loop aeroelastic poles; (13) closed-loop (control by LQR) aeroservoelastic poles; (14) gust response (random gusts) of the open-loop and closed-loop aeroservoelastic system, and, also, when aerodynamic loads are not present; and (15) deformation and stresses of passive or actively-controlled structures subject to dynamic and static loads. To

  2. Temporary cavity created by free-flying projectiles propelled from a powder-actuated nail gun.

    PubMed

    Frank, Matthias; Schönekeß, Holger C; Jäger, Frank; Hertel, Heinz; Ekkernkamp, Axel; Bockholdt, Britta

    2012-09-01

    Nails and driving pins discharged from powder-actuated fastening tools bear some special ballistic characteristics. Compared to the usual pistol or revolver projectiles, the sectional density (S) of fastening pins is extremely high. The general prevailing opinion is that the kinetic energy delivered by fastening tools is not high enough to cause a temporary cavity. Therefore, it was the aim of this study to investigate the wound morphology due to fastening bolts discharged from a powder-actuated direct-acting nail gun (where, in contrast to modern piston-type tools, the expanding gases act directly on the fastener) using ballistic soap blocks as simulants. For test shots, a direct-acting powder-actuated nail gun which features three interchangeable barrels (caliber (cal.) 6, 8, and 10 mm) was used. The average kinetic energy was 537, 532, and 694 J for the 6-, 8-, and 10-mm cal. bolts, respectively. Test shots on the ballistic soap blocks demonstrated that free-flying projectiles discharged from direct-acting fastening tools are able to create a temporary cavity. PMID:22797891

  3. Temporary cavity created by free-flying projectiles propelled from a powder-actuated nail gun.

    PubMed

    Frank, Matthias; Schönekeß, Holger C; Jäger, Frank; Hertel, Heinz; Ekkernkamp, Axel; Bockholdt, Britta

    2012-09-01

    Nails and driving pins discharged from powder-actuated fastening tools bear some special ballistic characteristics. Compared to the usual pistol or revolver projectiles, the sectional density (S) of fastening pins is extremely high. The general prevailing opinion is that the kinetic energy delivered by fastening tools is not high enough to cause a temporary cavity. Therefore, it was the aim of this study to investigate the wound morphology due to fastening bolts discharged from a powder-actuated direct-acting nail gun (where, in contrast to modern piston-type tools, the expanding gases act directly on the fastener) using ballistic soap blocks as simulants. For test shots, a direct-acting powder-actuated nail gun which features three interchangeable barrels (caliber (cal.) 6, 8, and 10 mm) was used. The average kinetic energy was 537, 532, and 694 J for the 6-, 8-, and 10-mm cal. bolts, respectively. Test shots on the ballistic soap blocks demonstrated that free-flying projectiles discharged from direct-acting fastening tools are able to create a temporary cavity.

  4. Note: Background Oriented Schlieren as a diagnostics for airflow control by plasma actuators.

    PubMed

    Biganzoli, I; Capone, C; Barni, R; Riccardi, C

    2015-02-01

    Background Oriented Schlieren (BOS) is an optical technique sensitive to the first spatial derivative of the refractive index inside a light-transmitting medium. Compared to other Schlieren-like techniques, BOS is more versatile and allows to capture bi-dimensional gradients rather than just one spatial component. We propose to adopt BOS for studying the capabilities of surface dielectric barrier discharges to work like plasma actuators in flow control applications. The characteristics of the BOS we implemented at this purpose are discussed, together with few results concerning the ionic wind produced by the discharge in absence of an external airflow.

  5. Note: Background Oriented Schlieren as a diagnostics for airflow control by plasma actuators

    NASA Astrophysics Data System (ADS)

    Biganzoli, I.; Capone, C.; Barni, R.; Riccardi, C.

    2015-02-01

    Background Oriented Schlieren (BOS) is an optical technique sensitive to the first spatial derivative of the refractive index inside a light-transmitting medium. Compared to other Schlieren-like techniques, BOS is more versatile and allows to capture bi-dimensional gradients rather than just one spatial component. We propose to adopt BOS for studying the capabilities of surface dielectric barrier discharges to work like plasma actuators in flow control applications. The characteristics of the BOS we implemented at this purpose are discussed, together with few results concerning the ionic wind produced by the discharge in absence of an external airflow.

  6. Application-oriented simplification of actuation mechanism and physical model for ionic polymer-metal composites

    NASA Astrophysics Data System (ADS)

    Zhu, Zicai; Wang, Yanjie; Liu, Yanfa; Asaka, Kinji; Sun, Xiaofei; Chang, Longfei; Lu, Pin

    2016-07-01

    Water containing ionic polymer-metal composites (IPMCs) show complex deformation properties with water content. In order to develop a simple application-oriented model for engineering application, actuation mechanisms and model equations should be simplified as necessary. Beginning from our previous comprehensive multi-physical model of IPMC actuator, numerical analysis was performed to obtain the main factors influencing the bending deformation and the corresponding simplified model. In this paper, three aspects are mainly concerned. (1) Regarding mass transport process, the diffusion caused by concentration gradient mainly influences the concentrations of cation and water at the two electrode boundaries. (2) By specifying the transport components as hydrated cation and free water in the model, at the cathode, the hydrated cation concentration profile is more flat, whereas the concentrations of both free water and the total water show drastic changes. In general, the two influence the redistribution of cation and water but have little impact on deformation prediction. Thus, they can be ignored in the simplification. (3) An extended osmotic pressure is proposed to cover all eigen stresses simply with an effective osmotic coefficient. Combining with a few other linearized methods, a simplified model has been obtained by sacrificing the prediction precision on the transport process. Furthermore, the improved model has been verified by fitting with IPMC deformation evolved with water content. It shows that the simplified model has the ability to predict the complex deformations of IPMCs.

  7. An Orientation Measurement Method Based on Hall-effect Sensors for Permanent Magnet Spherical Actuators with 3D Magnet Array

    PubMed Central

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-01-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators. PMID:25342000

  8. An Orientation Measurement Method Based on Hall-effect Sensors for Permanent Magnet Spherical Actuators with 3D Magnet Array

    NASA Astrophysics Data System (ADS)

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

    2014-10-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  9. An orientation measurement method based on Hall-effect sensors for permanent magnet spherical actuators with 3D magnet array.

    PubMed

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-10-24

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  10. End to end assembly of CaO and ZnO nanosheets to propeller-shaped architectures by orientation attachment approaches

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Liu, Fang

    2015-06-01

    Inspired by the agitation effect of propellers, heterogeneous propeller- shaped CaO/ZnO architectures were assembled in aqueous solution. Preferred nucleation and growth of CaO and ZnO nuclei resulted in their hexagonal nanosheets, and they were end to end combined into propeller-shaped architectures by oriented rotation and attachment reactions. When propeller-shaped CaO/ZnO product was used as solid base catalyst to synthesize biodiesel, a high biodiesel yield of 97.5% was achieved. The predominant exposure of active O2- on CaO(0 0 2) and ZnO(0 0 0 2) planes in propeller-shaped CaO/ZnO, led to good catalytic activity and high yield of biodiesel.

  11. The dynamics and control of large flexible space structures, 2. Part A: Shape and orientation control using point actuators

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Reddy, A. S. S. R.

    1979-01-01

    The equations of planar motion for a flexible beam in orbit which includes the effects of gravity gradient torques and control torques from point actuators located along the beam was developed. Two classes of theorems are applied to the linearized form of these equations to establish necessary conditions for controlability for preselected actuator configurations. The feedback gains are selected: (1) based on the decoupling of the original coordinates and to obtain proper damping, and (2) by applying the linear regulator problem to the individual model coordinates separately. The linear control laws obtained using both techniques were evaluated by numerical integration of the nonlinear system equations. Numerical examples considering pitch and various number of modes with different combination of actuator numbers and locations are presented. The independent model control concept used earlier with a discretized model of the thin beam in orbit was reviewed for the case where the number of actuators is less than the number of modes. Results indicate that although the system is controllable it is not stable about the nominal (local vertical) orientation when the control is based on modal decoupling. An alternate control law not based on modal decoupling ensures stability of all the modes.

  12. Utility-oriented placement of actuator nodes with a collaborative serving scheme for facilitated business and working environments.

    PubMed

    Lei, Chi-Un; Chong, Woon Kian; Man, Ka Lok

    2014-01-01

    Places to be served by cyber-physical systems (CPS) are usually distributed unevenly over the area. Thus, different areas usually have different importance and values of serving. In other words, serving power can be excessive or insufficient in practice. Therefore, actuator nodes (ANs) in CPS should be focused on serving around points of interest (POIs) with considerations of "service utility." In this paper, a utility-oriented AN placement framework with a collaborative serving scheme is proposed. Through spreading serving duties among correctly located ANs, deployment cost can be reduced, utility of ANs can be fully utilized, and the system longevity can be improved. The problem has been converted into a binary integer linear programming optimization problem. Service fading, 3D placements, multiscenario placements, and fault-tolerant placements have been modeled in the framework. An imitated example of a CPS deployment in a smart laboratory has been used for evaluations. PMID:25110746

  13. Utility-Oriented Placement of Actuator Nodes with a Collaborative Serving Scheme for Facilitated Business and Working Environments

    PubMed Central

    2014-01-01

    Places to be served by cyber-physical systems (CPS) are usually distributed unevenly over the area. Thus, different areas usually have different importance and values of serving. In other words, serving power can be excessive or insufficient in practice. Therefore, actuator nodes (ANs) in CPS should be focused on serving around points of interest (POIs) with considerations of “service utility.” In this paper, a utility-oriented AN placement framework with a collaborative serving scheme is proposed. Through spreading serving duties among correctly located ANs, deployment cost can be reduced, utility of ANs can be fully utilized, and the system longevity can be improved. The problem has been converted into a binary integer linear programming optimization problem. Service fading, 3D placements, multiscenario placements, and fault-tolerant placements have been modeled in the framework. An imitated example of a CPS deployment in a smart laboratory has been used for evaluations. PMID:25110746

  14. Superconducting linear actuator

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce; Hockney, Richard

    1993-01-01

    Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.

  15. Solid propellants.

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Hutchison, J. J.

    1972-01-01

    The basic principles underlying propulsion by rocket motor are examined together with the configuration of a solid propellant motor. Solid propellants and their preparation are discussed, giving attention to homogeneous propellants, composite propellants, energetic considerations in choosing a solid propellant, the processing of composite propellants, and some examples of new developments. The performance of solid propellants is investigated, taking into account characteristics velocity, the specific impulse, and performance calculations. Aspects of propellant development considered include nonperformance requirements for solid propellants, the approach to development, propellant mechanical properties, and future trends.

  16. Application of Service Oriented Architecture for Sensors and Actuators in District Heating Substations

    PubMed Central

    Gustafsson, Jonas; Kyusakov, Rumen; Mäkitaavola, Henrik; Delsing, Jerker

    2014-01-01

    Hardwired sensor installations using proprietary protocols found in today's district heating substations limit the potential usability of the sensors in and around the substations. If sensor resources can be shared and re-used in a variety of applications, the cost of sensors and installation can be reduced, and their functionality and operability can be increased. In this paper, we present a new concept of district heating substation control and monitoring, where a service oriented architecture (SOA) is deployed in a wireless sensor network (WSN), which is integrated with the substation. IP-networking is exclusively used from sensor to server; hence, no middleware is needed for Internet integration. Further, by enabling thousands of sensors with SOA capabilities, a System of Systems approach can be applied. The results of this paper show that it is possible to utilize SOA solutions with heavily resource-constrained embedded devices in contexts where the real-time constrains are limited, such as in a district heating substation. PMID:25196165

  17. Application of service oriented architecture for sensors and actuators in district heating substations.

    PubMed

    Gustafsson, Jonas; Kyusakov, Rumen; Mäkitaavola, Henrik; Delsing, Jerker

    2014-08-21

    Hardwired sensor installations using proprietary protocols found in today's district heating substations limit the potential usability of the sensors in and around the substations. If sensor resources can be shared and re-used in a variety of applications, the cost of sensors and installation can be reduced, and their functionality and operability can be increased. In this paper, we present a new concept of district heating substation control and monitoring, where a service oriented architecture (SOA) is deployed in a wireless sensor network (WSN), which is integrated with the substation. IP-networking is exclusively used from sensor to server; hence, no middleware is needed for Internet integration. Further, by enabling thousands of sensors with SOA capabilities, a System of Systems approach can be applied. The results of this paper show that it is possible to utilize SOA solutions with heavily resource-constrained embedded devices in contexts where the real-time constrains are limited, such as in a district heating substation.

  18. Application of service oriented architecture for sensors and actuators in district heating substations.

    PubMed

    Gustafsson, Jonas; Kyusakov, Rumen; Mäkitaavola, Henrik; Delsing, Jerker

    2014-01-01

    Hardwired sensor installations using proprietary protocols found in today's district heating substations limit the potential usability of the sensors in and around the substations. If sensor resources can be shared and re-used in a variety of applications, the cost of sensors and installation can be reduced, and their functionality and operability can be increased. In this paper, we present a new concept of district heating substation control and monitoring, where a service oriented architecture (SOA) is deployed in a wireless sensor network (WSN), which is integrated with the substation. IP-networking is exclusively used from sensor to server; hence, no middleware is needed for Internet integration. Further, by enabling thousands of sensors with SOA capabilities, a System of Systems approach can be applied. The results of this paper show that it is possible to utilize SOA solutions with heavily resource-constrained embedded devices in contexts where the real-time constrains are limited, such as in a district heating substation. PMID:25196165

  19. The dynamics and control of large flexible space structures, 3. Part A: Shape and orientation control of a platform in orbit using point actuators

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Reddy, A. S. S. R.; Krishna, R.; James, P. K.

    1980-01-01

    The dynamics, attitude, and shape control of a large thin flexible square platform in orbit are studied. Attitude and shape control are assumed to result from actuators placed perpendicular to the main surface and one edge and their effect on the rigid body and elastic modes is modelled to first order. The equations of motion are linearized about three different nominal orientations: (1) the platform following the local vertical with its major surface perpendicular to the orbital plane; (2) the platform following the local horizontal with its major surface normal to the local vertical; and (3) the platform following the local vertical with its major surface perpendicular to the orbit normal. The stability of the uncontrolled system is investigated analytically. Once controllability is established for a set of actuator locations, control law development is based on decoupling, pole placement, and linear optimal control theory. Frequencies and elastic modal shape functions are obtained using a finite element computer algorithm, two different approximate analytical methods, and the results of the three methods compared.

  20. Plants control the properties and actuation of their organs through the orientation of cellulose fibrils in their cell walls.

    PubMed

    Burgert, Ingo; Fratzl, Peter

    2009-07-01

    Plants use the orientation of cellulose microfibrils to create cell walls with anisotropic properties related to specific functions. This enables organisms to control the shape and size of cells during growth, to adjust the mechanical performance of tissues, and to perform bending movements of organs. We review the key function of cellulose orientation in defining structural-functional relationships in cell walls from a biomechanics perspective, and illustrate this by examples mainly from our own work. First, primary cell-wall expansion largely depends on the organization of cellulose microfibrils in newly deposited tissue and model calculations allow an estimate of how their passive re-orientation may influence the growth of cells. Moreover, mechanical properties of secondary cell walls depend to a large extent on the orientation of cellulose fibrils and we discuss strategies whereby plants utilize this interrelationship for adaptation. Lastly, we address the question of how plants regulate complex organ movements by designing appropriate supramolecular architectures at the level of the cell wall. Several examples, from trees to grasses, show that the cellulose architecture in the cell wall may be used to direct the swelling or shrinking of cell walls and thereby generate internal growth stress or movement of organs.

  1. Shape-Memory-Alloy Actuator For Flight Controls

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    1995-01-01

    Report proposes use of shape-memory-alloy actuators, instead of hydraulic actuators, for aerodynamic flight-control surfaces. Actuator made of shape-memory alloy converts thermal energy into mechanical work by changing shape as it makes transitions between martensitic and austenitic crystalline phase states of alloy. Because both hot exhaust gases and cryogenic propellant liquids available aboard launch rockets, shape-memory-alloy actuators exceptionally suited for use aboard such rockets.

  2. Propellant isolation shutoff valve program

    NASA Technical Reports Server (NTRS)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  3. Propeller injuries.

    PubMed

    Mann, R J

    1976-05-01

    Water skiing, boat racing, skin and scuba diving, and pleasure boat cruising are increasing in popularity. As a result the incidence of injuries secondary to motor propellers is becoming more frequent. In a ten-year period from 1963 to 1973, I collected a total of nine cases. In some amputations were necessary, and in other cases amputations occurred at the time of injury. Problems with bacterial flora occurring in open sea water versus salt water enclosed near docks and fresh lake water are discussed. A review of the orthopedic literature revealed sparse information regarding propeller injuries.

  4. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2014-04-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings [5, 8]. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~ 100m in size) have been identified in Saturn's A ring through their propeller signature in the images [10, 7, 9, 11]. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring [6, 2]. In this paper we present our new results about by now classical A ring propellers and more enigmatic B ring population. Due to the presence of self-gravity wakes the analysis of propeller brightness in ISS images always bears some ambiguity [7, 9] and consequently the exact morphology of propellers is not a settled issue. In 2008 we obtained a fortunate Cassini Ultraviolet Imaging Spectrograph (UVIS) occultation of the largest A ring propeller Bleriot. Utilizing Cassini ISS images we obtain Bleriot orbit and demonstrate that UVIS Persei Rev42 occultation did cut across Bleriot about 100km downstream from the center. The occultation itself shows a prominent partial gap and higher density outer flanking wakes, while their orientation is consistent with a downstream cut. While in the UVIS occultation the partial gap is more prominent than the flanking wakes, the features mostly seen in Bleriot images are actually flanking wakes. One of the most interesting aspects of the A ring propellers are their wanderings, or longitudinal deviations from a pure circular orbit [11]. We numerically investigated the possibility of simple moon

  5. Linear actuation using milligram quantities of CL-20 and TAGDNAT.

    SciTech Connect

    Snedigar, Shane; Salton, Jonathan Robert; Tappan, Alexander Smith; Ball, James Patrick; Basiliere, Marc; Fischer, Gary John

    2009-07-01

    There are numerous applications for small-scale actuation utilizing pyrotechnics and explosives. In certain applications, especially when multiple actuation strokes are needed, or actuator reuse is required, it is desirable to have all gaseous combustion products with no condensed residue in the actuator cylinder. Toward this goal, we have performed experiments on utilizing milligram quantities of high explosives to drive a millimeter-diameter actuator with a stroke of 30 mm. Calculations were performed to select proper material quantities to provide 0.5 J of actuation energy. This was performed utilizing the thermochemical code Cheetah to calculate the impetus for numerous propellants and to select quantities based on estimated efficiencies of these propellants at small scales. Milligram quantities of propellants were loaded into a small-scale actuator and ignited with an ignition increment and hot wire ignition. Actuator combustion chamber pressure was monitored with a pressure transducer and actuator stroke was monitored using a laser displacement meter. Total actuation energy was determined by calculating the kinetic energy of reaction mass motion against gravity. Of the materials utilized, the best performance was obtained with a mixture of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and bis-triaminoguanidinium(3,3{prime}dinitroazotriazolate) (TAGDNAT).

  6. Piezoelectric actuated gimbal

    DOEpatents

    Tschaggeny, Charles W.; Jones, Warren F.; Bamberg, Eberhard

    2011-09-13

    A gimbal is described and which includes a fixed base member defining an axis of rotation; a second member concentrically oriented relative to the axis of rotation; a linear actuator oriented in immediate, adjoining force transmitting relation relative to the base member or to the second member, and which applies force along a linear axis which is tangential to the axis of rotation so as to cause the second member to rotate coaxially relative to the fixed base member; and an object of interest mounted to the second member such that the object of interest is selectively moved relative to the base member about the axis of rotation.

  7. Actuated atomizer

    NASA Technical Reports Server (NTRS)

    Tilton, Charles (Inventor); Weiler, Jeff (Inventor); Palmer, Randall (Inventor); Appel, Philip (Inventor)

    2008-01-01

    An actuated atomizer is adapted for spray cooling or other applications wherein a well-developed, homogeneous and generally conical spray mist is required. The actuated atomizer includes an outer shell formed by an inner ring; an outer ring; an actuator insert and a cap. A nozzle framework is positioned within the actuator insert. A base of the nozzle framework defines swirl inlets, a swirl chamber and a swirl chamber. A nozzle insert defines a center inlet and feed ports. A spool is positioned within the coil housing, and carries the coil windings having a number of turns calculated to result in a magnetic field of sufficient strength to overcome the bias of the spring. A plunger moves in response to the magnetic field of the windings. A stop prevents the pintle from being withdrawn excessively. A pintle, positioned by the plunger, moves between first and second positions. In the first position, the head of the pintle blocks the discharge passage of the nozzle framework, thereby preventing the atomizer from discharging fluid. In the second position, the pintle is withdrawn from the swirl chamber, allowing the atomizer to release atomized fluid. A spring biases the pintle to block the discharge passage. The strength of the spring is overcome, however, by the magnetic field created by the windings positioned on the spool, which withdraws the plunger into the spool and further compresses the spring.

  8. Actuator mechanism

    NASA Technical Reports Server (NTRS)

    Stange, W. C. (Inventor)

    1978-01-01

    An actuator mechanism is described, having a frame with a rotatable shaft supported in the frame, a positioning mechanism coupled to the shaft for rotating the shaft in two rotary positions, disposed approximately 180 degrees apart, and a pair of plungers coupled to the shaft. Each plunger is responsive to a control signal for applying bi-directional rotation to the shaft.

  9. Solid propellant rocket motor

    NASA Technical Reports Server (NTRS)

    Dowler, W. L.; Shafer, J. I.; Behm, J. W.; Strand, L. D. (Inventor)

    1973-01-01

    The characteristics of a solid propellant rocket engine with a controlled rate of thrust buildup to a desired thrust level are discussed. The engine uses a regressive burning controlled flow solid propellant igniter and a progressive burning main solid propellant charge. The igniter is capable of operating in a vacuum and sustains the burning of the propellant below its normal combustion limit until the burning propellant surface and combustion chamber pressure have increased sufficiently to provide a stable chamber pressure.

  10. Modular droplet actuator drive

    NASA Technical Reports Server (NTRS)

    Pollack, Michael G. (Inventor); Paik, Philip (Inventor)

    2011-01-01

    A droplet actuator drive including a detection apparatus for sensing a property of a droplet on a droplet actuator; circuitry for controlling the detection apparatus electronically coupled to the detection apparatus; a droplet actuator cartridge connector arranged so that when a droplet actuator cartridge electronically is coupled thereto: the droplet actuator cartridge is aligned with the detection apparatus; and the detection apparatus can sense the property of the droplet on a droplet actuator; circuitry for controlling a droplet actuator coupled to the droplet actuator connector; and the droplet actuator circuitry may be coupled to a processor.

  11. Memory metal actuator

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F. (Inventor)

    1985-01-01

    A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

  12. Carbon nanotube actuators

    PubMed

    Baughman; Cui; Zakhidov; Iqbal; Barisci; Spinks; Wallace; Mazzoldi; De Rossi D; Rinzler; Jaschinski; Roth; Kertesz

    1999-05-21

    Electromechanical actuators based on sheets of single-walled carbon nanotubes were shown to generate higher stresses than natural muscle and higher strains than high-modulus ferroelectrics. Like natural muscles, the macroscopic actuators are assemblies of billions of individual nanoscale actuators. The actuation mechanism (quantum chemical-based expansion due to electrochemical double-layer charging) does not require ion intercalation, which limits the life and rate of faradaic conducting polymer actuators. Unlike conventional ferroelectric actuators, low operating voltages of a few volts generate large actuator strains. Predictions based on measurements suggest that actuators using optimized nanotube sheets may eventually provide substantially higher work densities per cycle than any previously known technology.

  13. Settled Cryogenic Propellant Transfer

    NASA Technical Reports Server (NTRS)

    Kutter, Bernard F.; Zegler, Frank; Sakla, Steve; Wall, John; Hopkins, Josh; Saks, Greg; Duffey, Jack; Chato, David J.

    2006-01-01

    Cryogenic propellant transfer can significantly benefit NASA s space exploration initiative. LMSSC parametric studies indicate that "Topping off" the Earth Departure Stage (EDS) in LEO with approx.20 mT of additional propellant using cryogenic propellant transfer increases the lunar delivered payload by 5 mT. Filling the EDS to capacity in LEO with 78 mT of propellants increases the delivered payload by 20 mT. Cryogenic propellant transfer is directly extensible to Mars exploration in that it provides propellant for the Mars Earth Departure stage and in-situ propellant utilization at Mars. To enable the significant performance increase provided by cryogenic propellant transfer, the reliability and robustness of the transfer process must be guaranteed. By utilizing low vehicle acceleration during the cryogenic transfer the operation is significantly simplified and enables the maximum use of existing, reliable, mature upper stage cryogenic-fluid-management (CFM) techniques. Due to settling, large-scale propellant transfer becomes an engineering effort, and not the technology development endeavor required with zero-gravity propellant transfer. The following key CFM technologies are all currently implemented by settling on both the Centaur and Delta IV upper stages: propellant acquisition, hardware chilldown, pressure control, and mass gauging. The key remaining technology, autonomous rendezvous and docking, is already in use by the Russians, and must be perfected for NASA whether the use of propellant transfer is utilized or not.

  14. OMS engine shutoff valve and actuation system design and evaluation. [for space shuttles

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1974-01-01

    Shutoff valve and actuation system concepts that are most suitable for the Orbital Maneuvering Systems engine application were determined. Emphasis was placed on the ten year and 100 mission life requirement, propellant and propellant residue compatibility and weight. It was found that poppet or ball valves utilizing electric or electropneumatic actuation were most applicable. Preliminary design layouts of a number of valve and actuation concepts were prepared and analyzed to make the optimum concept selection. Pneumatic actuation systems were required to feature their own pneumatic supply so that for the quad redundant valve, it was necessary to include two pneumatic supply systems, one for each of the series legs of the quad redundant package. The requirement for the pneumatic package placed heavy reliability, weight, and maintenance penalties upon electropneumatic actuation systems. The two valve and actuation systems concepts selected featured electric torque motor operation and a poppet as well as a ball valve concept with a retractable seal.

  15. Biomimetic actuator

    NASA Astrophysics Data System (ADS)

    Bouda, Vaclav; Boudova, Lea; Haluzikova, Denisa

    2005-05-01

    The aim of the presentation is to propose an alternative model of mammalian skeletal muscle function, which reflects the simplicity of nature and can be applied in engineering. Van der Waals attractive and repulsive electrostatic forces are assumed to control the design of internal structures and functions of contractile units of the muscles - sarcomere. The role of myosin heads is crucial for the higher order formation. The model of the myosin head lattice is the working model for the sarcomere contraction interpretation. The contraction is interpreted as a calcium induced phase transition of the lattice, which results in relative actin-myosin sliding and/or force generation. The model should provide the engineering science with a simple analogy to technical actuators of high performance.

  16. Solid propellant motor

    NASA Technical Reports Server (NTRS)

    Shafer, J. I.; Marsh, H. E., Jr. (Inventor)

    1978-01-01

    A case bonded end burning solid propellant rocket motor is described. A propellant with sufficiently low modulus to avoid chamber buckling on cooling from cure and sufficiently high elongation to sustain the stresses induced without cracking is used. The propellant is zone cured within the motor case at high pressures equal to or approaching the pressure at which the motor will operate during combustion. A solid propellant motor with a burning time long enough that its spacecraft would be limited to a maximum acceleration of less than 1 g is provided by one version of the case bonded end burning solid propellant motor of the invention.

  17. Propeller/wing interaction

    NASA Technical Reports Server (NTRS)

    Witkowski, David P.; Johnston, Robert T.; Sullivan, John P.

    1989-01-01

    The present experimental investigation of the steady-state and unsteady-state effects due to the interaction between a tractor propeller's wake and a wing employs, in the steady case, wind tunnel measurements at low subsonic speed; results are obtained which demonstrate wing performance response to variations in configuration geometry. Other steady-state results involve the propeller-hub lift and side-force due to the wing's influence on the propeller. The unsteady effects of interaction were studied through flow visualization of propeller-tip vortex distortion over a wing, again using a tractor-propeller configuration.

  18. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  19. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  20. A Flight Dynamics Model for a Multi-Actuated Flexible Rocket Vehicle

    NASA Technical Reports Server (NTRS)

    Orr, Jeb S.

    2011-01-01

    A comprehensive set of motion equations for a multi-actuated flight vehicle is presented. The dynamics are derived from a vector approach that generalizes the classical linear perturbation equations for flexible launch vehicles into a coupled three-dimensional model. The effects of nozzle and aerosurface inertial coupling, sloshing propellant, and elasticity are incorporated without restrictions on the position, orientation, or number of model elements. The present formulation is well suited to matrix implementation for large-scale linear stability and sensitivity analysis and is also shown to be extensible to nonlinear time-domain simulation through the application of a special form of Lagrange s equations in quasi-coordinates. The model is validated through frequency-domain response comparison with a high-fidelity planar implementation.

  1. Controller modeling and evaluation for PCV electro-mechanical actuator

    NASA Astrophysics Data System (ADS)

    Parker, Joey K.

    1993-11-01

    Hydraulic actuators are currently used to operate the propellant control valves (PCV) for the space shuttle main engine (SSME) and other rocket engines. These actuators are characterized by large power to weight ratios, large force capabilities, and rapid accelerations, which favor their use in control valve applications. However, hydraulic systems are also characterized by susceptibility to contamination, which leads to frequent maintenance requirements. The Control Mechanisms Branch (EP34) of the Component Development Division of the Propulsion Laboratory at the Marshall Space Flight Center (MSFC) has been investigating the application of electromechanical actuators as replacements for the hydraulic units in PCV's over the last few years. This report deals with some testing and analysis of a PCV electromechanical actuator (EMA) designed and fabricated by HR Textron, Inc. This prototype actuator has undergone extensive testing by EP34 personnel since early 1993. At this time, the performance of the HR Textron PCV EMA does not meet requirements for position tracking.

  2. Controller modeling and evaluation for PCV electro-mechanical actuator

    NASA Technical Reports Server (NTRS)

    Parker, Joey K.

    1993-01-01

    Hydraulic actuators are currently used to operate the propellant control valves (PCV) for the space shuttle main engine (SSME) and other rocket engines. These actuators are characterized by large power to weight ratios, large force capabilities, and rapid accelerations, which favor their use in control valve applications. However, hydraulic systems are also characterized by susceptibility to contamination, which leads to frequent maintenance requirements. The Control Mechanisms Branch (EP34) of the Component Development Division of the Propulsion Laboratory at the Marshall Space Flight Center (MSFC) has been investigating the application of electromechanical actuators as replacements for the hydraulic units in PCV's over the last few years. This report deals with some testing and analysis of a PCV electromechanical actuator (EMA) designed and fabricated by HR Textron, Inc. This prototype actuator has undergone extensive testing by EP34 personnel since early 1993. At this time, the performance of the HR Textron PCV EMA does not meet requirements for position tracking.

  3. Microprocessor controlled force actuator

    NASA Technical Reports Server (NTRS)

    Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

    1986-01-01

    The mechanical and electrical design of a prototype force actuator for vibration control of large space structures (LSS) is described. The force actuator is an electromagnetic system that produces a force by reacting against a proof-mass. The actuator has two colocated sensors, a digital microcontroller, and a power amplifier. The total weight of actuator is .998 kg. The actuator has a steady state force output of approximately 2.75 N from approximately 2 Hz to well beyond 1000 Hz.

  4. Integrated piezoelectric actuators in deep drawing tools

    NASA Astrophysics Data System (ADS)

    Neugebauer, R.; Mainda, P.; Drossel, W.-G.; Kerschner, M.; Wolf, K.

    2011-04-01

    The production of car body panels are defective in succession of process fluctuations. Thus the produced car body panel can be precise or damaged. To reduce the error rate, an intelligent deep drawing tool was developed at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in cooperation with Audi and Volkswagen. Mechatronic components in a closed-loop control is the main differentiating factor between an intelligent and a conventional deep drawing tool. In correlation with sensors for process monitoring, the intelligent tool consists of piezoelectric actuators to actuate the deep drawing process. By enabling the usage of sensors and actuators at the die, the forming tool transform to a smart structure. The interface between sensors and actuators will be realized with a closed-loop control. The content of this research will present the experimental results with the piezoelectric actuator. For the analysis a production-oriented forming tool with all automotive requirements were used. The disposed actuators are monolithic multilayer actuators of the piezo injector system. In order to achieve required force, the actuators are combined in a cluster. The cluster is redundant and economical. In addition to the detailed assembly structures, this research will highlight intensive analysis with the intelligent deep drawing tool.

  5. Cryogenic Propellant Densification Study

    NASA Technical Reports Server (NTRS)

    Ewart, R. O.; Dergance, R. H.

    1978-01-01

    Ground and vehicle system requirements are evaluated for the use of densified cryogenic propellants in advanced space transportation systems. Propellants studied were slush and triple point liquid hydrogen, triple point liquid oxygen, and slush and triple point liquid methane. Areas of study included propellant production, storage, transfer, vehicle loading and system requirements definition. A savings of approximately 8.2 x 100,000 Kg can be achieved in single stage to orbit gross liftoff weight for a payload of 29,484 Kg by utilizing densified cryogens in place of normal boiling point propellants.

  6. Piezoceramic Actuator Placement for Acoustic Control of Panels

    NASA Technical Reports Server (NTRS)

    Bevan, Jeffrey S.

    2000-01-01

    Optimum placement of multiple traditional piezoceramic actuators is determined for active structural acoustic control of flat panels. The structural acoustic response is determined using acoustic radiation filters and structural surface vibration characteristics. Linear Quadratic Regulator (LQR) control is utilized to determine the optimum state feedback gain for active structural acoustic control. The optimum actuator location is determined by minimizing the structural acoustic radiated noise using a modified genetic algorithm. Experimental tests are conducted and compared to analytical results. Anisotropic piezoceramic actuators exhibit enhanced performance when compared to traditional isotropic piezoceramic actuators. As a result of the inherent isotropy, these advanced actuators develop strain along the principal material axis. The orientation of anisotropic actuators is investigated on the effect of structural vibration and acoustic control of curved and flat panels. A fully coupled shallow shell finite element formulation is developed to include anisotropic piezoceramic actuators for shell structures.

  7. Piezoceramic Actuator Placement for Acoustic Control of Panels

    NASA Technical Reports Server (NTRS)

    Bevan, Jeffrey S.; Turner, Travis L. (Technical Monitor)

    2001-01-01

    Optimum placement of multiple traditional piezoceramic actuators is determined for active structural acoustic control of flat panels. The structural acoustic response is determined using acoustic radiation filters and structural surface vibration characteristics. Linear Quadratic Regulator (LQR) control is utilized to determine the optimum state feedback gain for active structural acoustic control. The optimum actuator location is determined by minimizing the structural acoustic radiated noise using a modified genetic algorithm. Experimental tests are conducted and compared to analytical results. Anisotropic piezoceramic actuators exhibits enhanced performance when compared to traditional isotropic piezoceramic actuators. As a result of the inherent isotropy, these advanced actuators develop strain along the principal material axis. The orientation of anisotropic actuators is investigated on the effect of structural vibration and acoustic control of curved and flat panels. A fully coupled shallow shell finite element formulation is developed to include anisotropic piezoceramic actuators for shell structures.

  8. Micromachined electrostatic vertical actuator

    DOEpatents

    Lee, Abraham P.; Sommargren, Gary E.; McConaghy, Charles F.; Krulevitch, Peter A.

    1999-10-19

    A micromachined vertical actuator utilizing a levitational force, such as in electrostatic comb drives, provides vertical actuation that is relatively linear in actuation for control, and can be readily combined with parallel plate capacitive position sensing for position control. The micromachined electrostatic vertical actuator provides accurate movement in the sub-micron to micron ranges which is desirable in the phase modulation instrument, such as optical phase shifting. For example, compact, inexpensive, and position controllable micromirrors utilizing an electrostatic vertical actuator can replace the large, expensive, and difficult-to-maintain piezoelectric actuators. A thirty pound piezoelectric actuator with corner cube reflectors, as utilized in a phase shifting diffraction interferometer can be replaced with a micromirror and a lens. For any very precise and small amplitudes of motion` micromachined electrostatic actuation may be used because it is the most compact in size, with low power consumption and has more straightforward sensing and control options.

  9. 3-D viscous flow CFD analysis of the propeller effect on an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1993-01-01

    The time-marching Navier-Stokes code PARC3D was used to study the 3D viscous flow associated with an advanced ducted propeller subsonic inlet at take-off operating conditions. At a free stream Mach number of 0.2, experimental data for the inlet-with-propeller test model indicated that the airflow was attached on the cowl windward lip at an angle of attack of 25 deg became unstable at 29 deg, and separated at 30 deg. An experimental study with a similar inlet and without propeller (through-flow) indicated that flow separation occurred at an angle of attack a few degrees below the value observed when the inlet was tested with the propeller, indicating the propeller's favorable effect on inlet performance. In the present numerical study, flow blockage analogous to the propeller was modeled via a PARC3D computational boundary condition (BC), the 'screen BC', based on 1-1/2 dimension actuator disk theory. The application of the screen BC in this numerical study provided results similar to those of past experimental efforts in which either the blockage device or the propeller was used.

  10. Mobile propeller dynamometer validation

    NASA Astrophysics Data System (ADS)

    Morris, Mason Wade

    With growing interest in UAVs and OSU's interest in propeller performance and manufacturing, evaluating UAV propeller and propulsion system performance has become essential. In attempts to evaluate these propellers a mobile propeller dynamometer has been designed, built, and tested. The mobile dyno has been designed to be cost effective through the ability to load it into the back of a test vehicle to create simulated forward flight characteristics. This allows much larger propellers to be dynamically tested without the use of large and expensive wind tunnels. While evaluating the accuracy of the dyno, several improvements had to be made to get accurate results. The decisions made to design and improve the mobile propeller dyno will be discussed along with attempts to validate the dyno by comparing its results against known sources. Another large part of assuring the accuracy of the mobile dyno is determining if the test vehicle will influence the flow going into the propellers being tested. The flow into the propeller needs to be as smooth and uniform as possible. This is determined by characterizing the boundary layer and accelerated flow over the vehicle. This evaluation was accomplished with extensive vehicle aerodynamic measurements with the use of full-scale tests using a pitot-rake and the actual test vehicle. Additional tests were conducted in Oklahoma State University's low speed wind tunnel with a 1/8-scale model using qualitative flow visualization with smoke. Continuing research on the mobile dyno will be discussed, along with other potential uses for the dyno.

  11. Liquid propellant densification

    NASA Technical Reports Server (NTRS)

    Lak, Tibor I. (Inventor); Petrilla, Steve P. (Inventor); Lozano, Martin E. (Inventor)

    1997-01-01

    Super cooling the cryogenic liquid propellant in a vehicle propellant tank densities the propellant allowing the vehicle propellant tank to carry more fuel in the same volume tank while lowering the vapor pressure and thus the tank operating pressure. Lowering the tank operating pressure reduces the stress and therefore allows the walls of the tank to be thinner. Both the smaller tank volume and thinner tank wall results in an overall smaller and lighter vehicle with increased payload capability. The cryogenic propellant can be supercooled well below the normal boiling point temperature level by transporting the liquid propellant from the vehicle tanks to a ground based cooling unit which utilizes a combination of heat exchanger and compressor. The compressor lowers the coolant fluid bath pressure resulting in a low temperature boiling liquid which is subsequently used to cool the recirculating liquid. The cooled propellant is then returned to the vehicle propellant tank. In addition to reducing the vehicle size and weight the invention also allows location of the vent valve on the ground, elimination of on-board recirculation pumps or bleed systems, smaller and lighter engine pumps and valves, lighter and more stable ullage gas, and significant reduction in tank fill operation. All of these mentioned attributes provide lower vehicle weight and cost.

  12. Return of the propeller

    SciTech Connect

    Not Available

    1987-05-01

    Resurrecting the propeller-driven airplane could help save fuel if there is another oil crisis like in the 1970s. This article discusses the new propeller engine, propfans, which are being developed for commercial airplanes. It discusses the three types of propfan engines and the advantages and disadvantages of each. It also tells about the propfan airplanes several companies are developing.

  13. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  14. Carbon nanotube array actuators

    NASA Astrophysics Data System (ADS)

    Geier, S.; Mahrholz, T.; Wierach, P.; Sinapius, M.

    2013-09-01

    Experimental investigations of highly vertically aligned carbon nanotubes (CNTs), also known as CNT-arrays, are the main focus of this paper. The free strain as result of an active material behavior is analyzed via a novel experimental setup. Previous test experiences of papers made of randomly oriented CNTs, also called Bucky-papers, reveal comparably low free strain. The anisotropy of aligned CNTs promises better performance. Via synthesis techniques like chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD), highly aligned arrays of multi-walled carbon nanotubes (MWCNTs) are synthesized. Two different types of CNT-arrays are analyzed, morphologically first, and optically tested for their active characteristics afterwards. One type of the analyzed arrays features tube lengths of 750-2000 μm with a large variety of diameters between 20 and 50 nm and a wave-like CNT-shape. The second type features a maximum, almost uniform, length of 12 μm and a constant diameter of 50 nm. Different CNT-lengths and array types are tested due to their active behavior. As result of the presented tests, it is reported that the quality of orientation is the most decisive property for excellent active behavior. Due to their alignment, CNT-arrays feature the opportunity to clarify the actuation mechanism of architectures made of CNTs.

  15. Subminiature hydraulic actuator

    NASA Technical Reports Server (NTRS)

    Sevart, F. D.

    1978-01-01

    Subminiature, single-vane rotary actuator for wind-tunnel test-model control-surface actuation systems presents severe torque and system band-pass requirements with stringent space and weight limitations. Actuator has very low leakage of fluid from one side to other, permitting use in precision position servo-systems.

  16. AMSD Cryo Actuator Testing

    NASA Technical Reports Server (NTRS)

    Mullette, Mark; Matthews, Gary; Russell, Kevin (Technical Monitor)

    2002-01-01

    The actuator technology required for AMSD and subsequently NGST are critical in the successful development for future cryogenic systems. Kodak has undertaken an extensive test plan to determine the performance of the force actuators developed under the AMSD program. These actuators are currently in testing at MSFC and are expected to finish this test cycle in early June 2002.

  17. Propellant-remaining modeling

    NASA Technical Reports Server (NTRS)

    Torgovitsky, S.

    1991-01-01

    A successful satellite mission is predicted upon the proper maintenance of the spacecraft's orbit and attitude. One requirement for planning and predicting the orbit and attitude is the accurate estimation of the propellant remaining onboard the spacecraft. Focuss is on the three methods that were developed for calculating the propellant budget: the errors associated with each method and the uncertainties in the variables required to determine the propellant remaining that contribute to these errors. Based on these findings, a strategy is developed for improved propellant-remaining estimation. The first method is based on Boyle's law, which related the values of pressure, volume, and temperature (PVT) of an ideal gas. The PVT method is used for the monopropellant and the bipropellant engines. The second method is based on the engine performance tests, which provide data that relate thrust and specific impulse associated with a propellant tank to that tank's pressure. Two curves representing thrust and specific impulse as functions of pressure are then generated using a polynomial fit on the engine performance data. The third method involves a computer simulation of the propellant system. The propellant flow is modeled by creating a conceptual model of the propulsion system configuration, taking into account such factors as the propellant and pressurant tank characteristics, thruster functionality, and piping layout. Finally, a thrust calibration technique is presented that uses differential correction with the computer simulation method of propellant-remaining modeling. Thrust calibration provides a better assessment of thruster performance and therefore enables a more accurate estimation of propellant consumed during a given maneuver.

  18. Nitramine propellants. [gun propellant burning rate

    NASA Technical Reports Server (NTRS)

    Cohen, N. S.; Strand, L. D. (Inventor)

    1978-01-01

    Nitramine propellants without a pressure exponent shift in the burning rate curves are prepared by matching the burning rate of a selected nitramine or combination of nitramines within 10% of burning rate of a plasticized active binder so as to smooth out the break point appearance in the burning rate curve.

  19. Omnidirectional Actuator Handle

    NASA Technical Reports Server (NTRS)

    Moetteli, John B.

    1995-01-01

    Proposed actuator handle comprises two normally concentric rings, cables, and pulleys arranged such that relative displacement of rings from concentricity results in pulling of cable and consequent actuation of associated mechanism. Unlike conventional actuator handles like levers on farm implements, actuated from one or two directions only, proposed handle reached from almost any direction and actuated by pulling or pushing inner ring in any direction with respect to outer ring. Flanges installed on inner ring to cover gap between inner ring and housing to prevent clothing from being caught.

  20. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  1. Nitramine smokeless propellant research

    NASA Technical Reports Server (NTRS)

    Cohen, N. S.; Strand, L. P.

    1977-01-01

    A transient ballistics and combustion model is derived to represent the closed vessel experiment that is widely used to characterize propellants. A computer program is developed to solve the time-dependent equations, and is applied to explain aspects of closed vessel behavior. In the case of nitramine propellants the cratering of the burning surface associated with combustion above break-point pressures augments the effective burning rate as deduced from the closed vessel experiment. Low pressure combustion is significantly affected by the ignition process and, in the case of nitramine propellants, by the developing and changing surface structure. Thus, burning rates deduced from the closed vessel experiment may or may not agree with those measured in the equilibrium strand burner. Series of T burner experiments are performed to compare the combustion instability characteristics of nitramine (HMX) containing propellants and ammonium perchlorate (AP)propellants. Although ash produced by more fuel rich propellants could have provided mechanical suppression, results from clean-burning propellants permit the conclusion that HMX reduces the acoustic driving.

  2. Microgravity liquid propellant management

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1990-01-01

    The requirement to settle or to position liquid fluid over the outlet end of a spacecraft propellant tank prior to main engine restart, poses a microgravity fluid behavior problem. Resettlement or reorientation of liquid propellant can be accomplished by providing optimal acceleration to the spacecraft such that the propellant is reoriented over the tank outlet without any vapor entrainment, any excessive geysering, or any other undersirable fluid motion for the space fluid management under microgravity environment. The most efficient technique is studied for propellant resettling through the minimization of propellant usage and weight penalties. Both full scale and subscale liquid propellant tank of Space Transfer Vehicle were used to simulate flow profiles for liquid hydrogen reorientation over the tank outlet. In subscale simulation, both constant and impulsive resettling acceleration were used to simulate the liquid flow reorientation. Comparisons between the constant reverse gravity acceleration and impulsive reverse gravity acceleration to be used for activation of propellant resettlement shows that impulsive reverse gravity thrust is superior to constant reverse gravity thrust.

  3. Automated Propellant Blending

    NASA Technical Reports Server (NTRS)

    Hohmann, Carl W. (Inventor); Harrington, Douglas W. (Inventor); Dutton, Maureen L. (Inventor); Tipton, Billy Charles, Jr. (Inventor); Bacak, James W. (Inventor); Salazar, Frank (Inventor)

    2000-01-01

    An automated propellant blending apparatus and method that uses closely metered addition of countersolvent to a binder solution with propellant particles dispersed therein to precisely control binder precipitation and particle aggregation is discussed. A profile of binder precipitation versus countersolvent-solvent ratio is established empirically and used in a computer algorithm to establish countersolvent addition parameters near the cloud point for controlling the transition of properties of the binder during agglomeration and finishing of the propellant composition particles. The system is remotely operated by computer for safety, reliability and improved product properties, and also increases product output.

  4. Automated Propellant Blending

    NASA Technical Reports Server (NTRS)

    Hohmann, Carl W. (Inventor); Harrington, Douglas W. (Inventor); Dutton, Maureen L. (Inventor); Tipton, Billy Charles, Jr. (Inventor); Bacak, James W. (Inventor); Salazar, Frank (Inventor)

    1999-01-01

    An automated propellant blending apparatus and method uses closely metered addition of countersolvent to a binder solution with propellant particles dispersed therein to precisely control binder precipitation and particle aggregation. A profile of binder precipitation versus countersolvent-solvent ratio is established empirically and used in a computer algorithm to establish countersolvent addition parameters near the cloud point for controlling the transition of properties of the binder during agglomeration and finishing of the propellant composition particles. The system is remotely operated by computer for safety, reliability and improved product properties, and also increases product output.

  5. High temperature propellant development

    NASA Technical Reports Server (NTRS)

    Anderson, F. A.

    1981-01-01

    It is reported that the neccessary technology has been developed and demonstrated for the manufacture of heat-sterilizable solid propellants which meet specific ballistic goals. It is shown that: (1) phosphate doping of ammonium perchlorate significantly enhances the thermal stability of the substance; (2) grinding the ammonium perchlorate to reduce particle size further increases thermal stability; and (3) unsaturated polymers such as the polybutadienes can be successfully used in a heat-sterilizable propellant system. Among the topics considered by the study are oxidizers, dopants, binders, and the thermal cycling of 70 lb and 600 lb propellant grains.

  6. Nitramine smokeless propellant research

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A transient ballistics and combustion model was derived to represent the closed vessel experiment that is widely used to characterize propellants. The model incorporates the nitramine combustion mechanisms. A computer program was developed to solve the time dependent equations, and was applied to explain aspects of closed vessel behavior. It is found that the rate of pressurization in the closed vessel is insufficient at pressures of interest to augment the burning rate by time dependent processes. Series of T-burner experiments were performed to compare the combustion instability characteristics of nitramine (HMX) containing propellants and ammonium perchlorate (AP) propellants. It is found that the inclusion of HMX consistently renders the propellant more stable.

  7. Electropneumatic actuator, phase 1

    NASA Astrophysics Data System (ADS)

    Bloomfield, D. P.

    1989-10-01

    The program demonstrated the feasibility of an electropneumatic actuator which can be used in manufacturing applications. The electropneumatic actuator, an alternative to the electric, hydraulic, and pneumatic actuators used in industry, consists of an electrochemical compressor, a power supply, and an actuator. The electrochemical compressor working fluid is hydrogen and a solvent such as water or ammonia. The compressor has no moving parts and runs on low voltage DC. The actuator is a conventional, commercially available unit. Researchers designed, constructed, and tested the electrochemical compressor in conjunction with the actuator, power supply, and computerized control. The one inch actuator can lift a fifty pound weight a distance of ten inches in about 1.5 minutes. The electrochemically powered system is capable of driving its loaded actuator to a prescribed location at a controlled rate. A defined set of design changes will combine the compressor and actuator in the same housing, and will develop two orders of magnitude increased actuator speed at the same or higher force levels.

  8. Advanced propeller research

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.; Bober, Lawrence J.

    1987-01-01

    Resent results of aerodynamic and acoustic research on both single and counter-rotation propellers are reviewed. Data and analytical results are presented for three propellers: SR-7A, the single rotation design used in the NASA Propfan Test Assessment (PTA); and F7-A7, the 8+8 counterrotating design used in the proof-of-concept Unducted Fan (UDF) engine. In addition to propeller efficiencies, cruise and takeoff noise, and blade pressure data, off-design phenomena involving formation of leading edge vortices are described. Aerodynamic and acoustic computational results derived from three-dimensional Euler and acoustic radiation codes are presented. Research on unsteady flows, which are particularly important for understanding counterrotation interaction noise, unsteady loading effects on acoustics, and flutter or forced response is described. The first results of three-dimensional unsteady Euler solutions are illustrated for a single rotation propeller at an angle of attack and for a counterrotation propeller. Basic experimental and theoretical results from studies of the unsteady aerodynamics of oscillating cascades are outlined. Finally, advanced concepts involving swirl recovery vanes and ultra bypass ducted propellers are discussed.

  9. Modeling liquid crystal elastomers: actuators, pumps, and robots

    NASA Astrophysics Data System (ADS)

    Selinger, Robin L. B.; Mbanga, Badel L.; Selinger, Jonathan V.

    2008-02-01

    We model the dynamics of shape evolution of liquid crystal elastomers (LCE) in three dimensions using finite element elastodynamics. The model predicts the macroscopic mechanical response induced by changes in nematic order, e.g. by heating or cooling through the isotropic/nematic transition or, in azo-doped materials, by exposure to light. We model the performance of LCE actuator devices including multicomponent actuators, peristaltic pumps and self-propelled robots. The goal of this work is to build a bridge between basic soft matter theory and practical materials engineering/device design. Supported by NSF-DMR-0605889.

  10. Circular motion of asymmetric self-propelling particles.

    PubMed

    Kümmel, Felix; ten Hagen, Borge; Wittkowski, Raphael; Buttinoni, Ivo; Eichhorn, Ralf; Volpe, Giovanni; Löwen, Hartmut; Bechinger, Clemens

    2013-05-10

    Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft lithography and study their circular motion on a substrate and near channel boundaries. Our experimental observations are in full agreement with a theory of Brownian dynamics for asymmetric self-propelled particles, which couples their translational and orientational motion. PMID:23705745

  11. Circular Motion of Asymmetric Self-Propelling Particles

    NASA Astrophysics Data System (ADS)

    Kümmel, Felix; ten Hagen, Borge; Wittkowski, Raphael; Buttinoni, Ivo; Eichhorn, Ralf; Volpe, Giovanni; Löwen, Hartmut; Bechinger, Clemens

    2013-05-01

    Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft lithography and study their circular motion on a substrate and near channel boundaries. Our experimental observations are in full agreement with a theory of Brownian dynamics for asymmetric self-propelled particles, which couples their translational and orientational motion.

  12. Propellant Readiness Level: A Methodological Approach to Propellant Characterization

    NASA Technical Reports Server (NTRS)

    Bossard, John A.; Rhys, Noah O.

    2010-01-01

    A methodological approach to defining propellant characterization is presented. The method is based on the well-established Technology Readiness Level nomenclature. This approach establishes the Propellant Readiness Level as a metric for ascertaining the readiness of a propellant or a propellant combination by evaluating the following set of propellant characteristics: thermodynamic data, toxicity, applications, combustion data, heat transfer data, material compatibility, analytical prediction modeling, injector/chamber geometry, pressurization, ignition, combustion stability, system storability, qualification testing, and flight capability. The methodology is meant to be applicable to all propellants or propellant combinations; liquid, solid, and gaseous propellants as well as monopropellants and propellant combinations are equally served. The functionality of the proposed approach is tested through the evaluation and comparison of an example set of hydrocarbon fuels.

  13. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~<500m in size) have been indirectly identified in Saturn's A ring through their propeller signature in the images. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring. In this paper we present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B

  14. MEMS fluidic actuator

    DOEpatents

    Kholwadwala, Deepesh K.; Johnston, Gabriel A.; Rohrer, Brandon R.; Galambos, Paul C.; Okandan, Murat

    2007-07-24

    The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

  15. Q-ball imaging with PROPELLER EPI acquisition.

    PubMed

    Chou, Ming-Chung; Huang, Teng-Yi; Chung, Hsiao-Wen; Hsieh, Tsyh-Jyi; Chang, Hing-Chiu; Chen, Cheng-Yu

    2013-12-01

    Q-ball imaging (QBI) is an imaging technique that is capable of resolving intravoxel fiber crossings; however, the signal readout based on echo-planar imaging (EPI) introduces geometric distortions in the presence of susceptibility gradients. This study proposes an imaging technique that reduces susceptibility distortions in QBI by short-axis PROPELLER EPI acquisition. Conventional QBI and PROPELLER QBI data were acquired from two 3T MR scans of the brains of five healthy subjects. Prior to the PROPELLER reconstruction, residual distortions in single-blade low-resolution b0 and diffusion-weighted images (DWIs) were minimized by linear affine and nonlinear diffeomorphic demon registrations. Subsequently, the PROPELLER keyhole reconstruction was applied to the corrected DWIs to obtain high-resolution PROPELLER DWIs. The generalized fractional anisotropy and orientation distribution function maps contained fewer distortions in PROPELLER QBI than in conventional QBI, and the fiber tracts more closely matched the brain anatomy depicted by turbo spin-echo (TSE) T2-weighted imaging (T2WI). Furthermore, for fixed T(E), PROPELLER QBI enabled a shorter scan time than conventional QBI. We conclude that PROPELLER QBI can reduce susceptibility distortions without lengthening the acquisition time and is suitable for tracing neuronal fiber tracts in the human brain.

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

    NASA Technical Reports Server (NTRS)

    Gummin, Mark A.

    2013-01-01

    Shape memory alloy (SMA) actuators provide the highest force-to-weight ratio of any known actuator. They can be designed for a wide variety of form factors from flat, thin packages, to form-matching packages for existing actuators. SMA actuators can be operated many thousands of times, so that ground testing is possible. Actuation speed can be accurately controlled from milliseconds to position and hold, and even electronic velocity-profile control is possible. SMA actuators provide a high degree of operational flexibility, and are truly smart actuators capable of being accurately controlled by onboard microprocessors across a wide range of voltages. The Miga Aero actuator is a SMA actuator designed specifically for spaceflight applications. Providing 13 mm of stroke with either 20- or 40-N output force in two different models, the Aero actuator is made from low-outgassing PEEK (polyether ether ketone) plastic, stainless steel, and nickel-titanium SMA wires. The modular actuator weighs less than 28 grams. The dorsal output attachment allows the Aero to be used in either PUSH or PULL modes by inverting the mounting orientation. The SPA1 actuator utilizes commercially available SMA actuator wire to provide 3/8-in. (approx. =.1 cm) of stroke at a force of over 28 lb (approx. = .125 N). The force is provided by a unique packaging of the single SMA wire that provides the output force of four SMA wires mechanically in parallel. The output load is shared by allowing the SMA wire to slip around the output attachment end to adjust or balance the load, preventing any individual wire segment from experiencing high loads during actuation. A built-in end limit switch prevents overheating of the SMA element following actuation when used in conjunction with the Miga Analog Driver [a simple MOSFET (metal oxide semiconductor field-effect transistor) switching circuit]. A simple 2D machined mechanical binary latch has been developed to complement the capabilities of SMA wire

  17. Understanding the Space Shuttle Main Engine Hydraulic Actuation System and Reviewing Its Evolution

    NASA Technical Reports Server (NTRS)

    McWade, Robert J.; Minor, Robert B.; McNutt, Leslie M.

    2010-01-01

    The complex engine start and thrust control requirements of the Space Shuttle Main Engine (SSME) require unique valve, actuator and control system hardware. The Hydraulic Actuation System (HAS) was designed, developed, and now operates to meet tight engine control requirement limits to assure safe, reliable and correct engine thrust at all times. The actuator is designed to be fail safe and fail operate in the areas where redundancy is important. The HAS has an additional pneumatic operating capability that insures a safe sequential closure of all actuators and propellant valves in the event of the loss of hydraulic system pressure or loss of electrical closed loop control of the actuator. The objective of this paper is to provide a complete description of the actuator s internal operating system, along with its interaction with all SSME system interfaces. Additionally the paper addresses the challenges, problems identified, and corrected, and lessons learned, during the course of the almost 35 years of engine operation.

  18. Improved Electrohydraulic Linear Actuators

    NASA Technical Reports Server (NTRS)

    Hamtil, James

    2004-01-01

    A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also adaptable to many industrial uses, such as steam turbines, process control valves, dampers, motion control, etc. The advantageous features of the improved electrohydraulic linear actuators are best described with respect to shortcomings of prior electrohydraulic linear actuators that the improved ones are intended to supplant. The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal (a current having a value between 4 and 20 mA) from a supervisory control system of the facility. As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position.

  19. Comprehensive piezoceramic actuator review

    NASA Astrophysics Data System (ADS)

    Taylor, Chris J.; Washington, Gregory N.

    2002-07-01

    Piezoceramic actuation has become an area of increased interest in the past ten years. Having been used for many years as sensors in such applications as pressure transducers and smoke detectors, piezoceramics are now being used as prime movers in fuel injectors and valve lifters. In an effort to aid the engineering community, this paper will conduct a comprehensive review of several piezoceramic actuators. Classical design parameters will be derived for each actuator such as blocked force and free stroke. In addition, more esoteric entities such as mechanical efficiency and energy density will also be derived. The result will be design metrics of popular piezoceramic actuators containing vital design equations, validated with empirical data. Of the many different configurations of piezoceramic actuators, this paper will investigate the bimorph and unimorph bender. These actuator types are finding increased use in semi-active structural damping, energy harvesting and vibration control. The work in this paper will show experimental verification of various actuator types as well as theoretical derivations. In addition to unimorphs, bimorphs and stack actuators a novel type of unimorph bender, the THUNDER actuator (developed and licensed by NASA) will be included in the review.

  20. The 3-D viscous flow CFD analysis of the propeller effect on an advanced ducted propeller subsonic inlet

    NASA Technical Reports Server (NTRS)

    Iek, Chanthy; Boldman, Donald R.; Ibrahim, Mounir

    1993-01-01

    A time marching Navier-Stokes code called PARC3D was used to study the 3-D viscous flow associated with an advanced ducted propeller (ADP) subsonic inlet at take-off operating conditions. At a free stream Mach number of 0.2, experimental data for the inlet-with-propeller test model indicated that the airflow was attached on the cowl windward lip at an angle of attack of 25 degrees became unstable at 29 degrees, and separated at 30 degrees. An experimental study with a similar inlet and with no propeller (through-flow) indicated that flow separation occurred at an angle of attack a few degrees below the value observed when the inlet was tested with the propeller. This tends to indicate that the propeller exerts a favorable effect on the inlet performance. During the through-flow experiment a stationary blockage device was used to successfully simulate the propeller effect on the inlet flow field at angles of attack. In the present numerical study, this flow blockage was modeled via a PARC3D computational boundary condition (BC) called the screen BC. The principle formulation of this BC was based on the one-and-half dimension actuator disk theory. This screen BC was applied at the inlet propeller face station of the computational grid. Numerical results were obtained with and without the screen BC. The application of the screen BC in this numerical study provided results which are similar to the results of past experimental efforts in which either the blockage device or the propeller was used.

  1. Line Fluid Actuated Valve Development Program. [for application on the space shuttle

    NASA Technical Reports Server (NTRS)

    Lynch, R. A.

    1975-01-01

    The feasibility of a line-fluid actuated valve design for potential application as a propellant-control valve on the space shuttle was examined. Design and analysis studies of two prototype valve units were conducted and demonstrated performance is reported. It was shown that the line-fluid actuated valve concept offers distinct weight and electrical advantages over alternate valve concepts. Summaries of projected performance and design goals are also included.

  2. Advanced propeller research

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.; Bober, Lawrence J.

    1990-01-01

    Recent results of aerodynamic and acoustic research on both single rotation and counterrotation propellers are reviewed. Data and analytical results are presented for three propellers: SR-7A, the single rotation design used in the NASA Propfan Test Assessment (PTA) flight program; CRP-X1, the initial 5+5 Hamilton Standard counterrotating design; and F7-A7, the 8+8 counterrotating G.E. design used in the proof of concept Unducted Fan (UDF) engine. In addition to propeller efficiencies, cruise and takeoff noise, and blade pressure data, off-design phenomena involving formation of leading edge vortexes are described. Aerodynamic and acoustic computational results derived from 3-D Euler and acoustic radiation codes are presented. Research on unsteady flows which are particularly important for understanding counterrotation interaction noise, unsteady loading effects on acoustics, and flutter or forced response is described. The first results of 3-D unsteady Euler solutions are illustrated for a single rotation propeller at angle of attack and for a counterrotation propeller. Basic experimental and theoretical results from studies on the unsteady aerodynamics of oscillating cascades are outlined.

  3. Aeroacoustics of advanced propellers

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.

    1990-01-01

    The aeroacoustics of advanced, high speed propellers (propfans) are reviewed from the perspective of NASA research conducted in support of the Advanced Turboprop Program. Aerodynamic and acoustic components of prediction methods for near and far field noise are summarized for both single and counterrotation propellers in uninstalled and configurations. Experimental results from tests at both takeoff/approach and cruise conditions are reviewed with emphasis on: (1) single and counterrotation model tests in the NASA Lewis 9 by 15 (low speed) and 8 by 6 (high speed) wind tunnels, and (2) full scale flight tests of a 9 ft (2.74 m) diameter single rotation wing mounted tractor and a 11.7 ft (3.57 m) diameter counterrotation aft mounted pusher propeller. Comparisons of model data projected to flight with full scale flight data show good agreement validating the scale model wind tunnel approach. Likewise, comparisons of measured and predicted noise level show excellent agreement for both single and counterrotation propellers. Progress in describing angle of attack and installation effects is also summarized. Finally, the aeroacoustic issues associated with ducted propellers (very high bypass fans) are discussed.

  4. Actuating Fibers: Design and Applications.

    PubMed

    Stoychev, Georgi V; Ionov, Leonid

    2016-09-21

    Actuators are devices capable of moving or controlling objects and systems by applying mechanical force on them. Among all kinds of actuators with different shapes, fibrous ones deserve particular attention. In spite of their apparent simplicity, actuating fibers allow for very complex actuation behavior. This review discusses different approaches for the design of actuating fibers, and their advantages and disadvantages. We also discuss the prospects for the design of fibers with advanced architectures and complex actuation behavior. PMID:27571481

  5. Lock for hydraulic actuators

    NASA Technical Reports Server (NTRS)

    Wood, R. H.

    1981-01-01

    Two clamps hold rod in fixed extension from cylinder even when power is off, converting actuator into stiff structural member. Locked actuator is useful as mechanical support or linkage or as fail-safe device in case of loss of hydraulic pressure. Potential applications include manufacturing processes and specialized handling and holding devices.

  6. Propeller pitch change mechanism

    SciTech Connect

    Hora, P.

    1992-10-13

    This patent describes an aircraft propulsion system. It comprises: a first turbine carrying a first set of propeller blades; a second turbine carrying a second set of propeller blades; a gear system carried by the first turbine for changing pitch of the first set of propeller blades, which includes a pair of ring gears, both coaxial with the first turbine; a first set of planet gears which engage both ring gears and which induce pitch change when the planet gears rotate; a sun gear which drives the planet gears; a second set of planet gears which are carried by a planet gear carrier affixed to the second turbine and which drive the sun gear in order to change pitch by causing relative motion between the sung ear and the first turbine; and means for preventing a change in speed of the planet gear carrier from causing a change in pitch.

  7. Fundamental investigations of carbon nanotubes working as actuators

    NASA Astrophysics Data System (ADS)

    Geier, Sebastian; Schnoor, Thea; Riemenschneider, Johannes; Mahrholz, Thorsten; Wierach, Peter; Schulte, Karl; Sinapius, Michael

    2011-04-01

    Excellent properties like low density, high mechanical stiffness as well as an outstanding thermal and electrical conductivity make researchers focusing on carbon nanotubes (CNTs) since years. Beside that it is found that structures made of CNTs can be actuated when they are set up like a capacitor. Usually two dimensional (2D) CNT-papers with randomly oriented CNTs, called Bucky-papers, are used. They are charged and divided by an electrically insulating but ionic conductible electrolyte. Experiments demonstrate low voltages for actuation (+/-1V). Although the mechanism of CNT-actuation is still an open issue theoretical studies suggest a charge and ion induced lengthening of the C-bonds, which predict theoretical strains up to 1%. These characteristics make CNTs a potential candidate for lightweight and powerful actuators of future adaptive aerospace applications. The presented work gives an overview of possible CNT-actuator configurations. Comprehensive analysis tools for 2D mats of randomly oriented CNTs have been developed to guarantee a consistent data base for the comparison of different CNT-configurations. It is focused on the electro-mechanical properties with respect to the processing and configuration of CNT-actuators. For a more efficient use of the mechanical advantages of the CNT-geometry a new aligning manufacturing approach is presented, to get highly oriented 2D CNT-papers. Their properties are compared with randomly oriented CNT-papers. Finally a new test set-up will be introduced, which enables deflection measurements directly on the top of vertically aligned CNTs (CNT-arrays). The buildup and necessary prework are shown, as well as results of the first experiments. The method of measuring along the axis of aligned CNTs qualifies this set-up to get a deeper understanding about the actuation mechanism of CNTs. Vertically aligned CNTs promise to be a more efficient actuator configuration because of their high stiffness in direction of actuation.

  8. Fast electrochemical actuator

    NASA Astrophysics Data System (ADS)

    Uvarov, I. V.; Postnikov, A. V.; Svetovoy, V. B.

    2016-03-01

    Lack of fast and strong microactuators is a well-recognized problem in MEMS community. Electrochemical actuators can develop high pressure but they are notoriously slow. Water electrolysis produced by short voltage pulses of alternating polarity can overcome the problem of slow gas termination. Here we demonstrate an actuation regime, for which the gas pressure is relaxed just for 10 μs or so. The actuator consists of a microchamber filled with the electrolyte and covered with a flexible membrane. The membrane bends outward when the pressure in the chamber increases. Fast termination of gas and high pressure developed in the chamber are related to a high density of nanobubbles in the chamber. The physical processes happening in the chamber are discussed so as problems that have to be resolved for practical applications of this actuation regime. The actuator can be used as a driving engine for microfluidics.

  9. Optimum propeller wind turbines

    NASA Astrophysics Data System (ADS)

    Sanderson, R. J.; Archer, R. D.

    1983-12-01

    The Prandtl-Betz-Theodorsen theory of heavily loaded airscrews has been adapted to the design of propeller windmills which are to be optimized for maximum power coefficient. It is shown that the simpler, light-loading, constant-area wake assumption can generate significantly different 'optimum' performance and geometry, and that it is therefore not appropriate to the design of propeller wind turbines when operating in their normal range of high-tip-speed-to-wind-speed ratio. Design curves for optimum power coefficient are presented and an example of the design of a typical two-blade optimum rotor is given.

  10. Active synchrophasing of propeller unbalance

    NASA Technical Reports Server (NTRS)

    Kaptein, Dick

    1992-01-01

    The results of a survey are presented to reduce the inflight propeller unbalance vibrations in the cabin of the Fokker 50 airplanes. Several approaches have been investigated. Active synchrophasing of the unbalance vibrations of both propellers appears to be successful.

  11. Ducted propeller design and analysis

    SciTech Connect

    Weir, R.J.

    1987-10-01

    The theory and implementation of the design of a ducted propeller blade are presented and discussed. Straightener (anti-torque) vane design is also discussed. Comparisons are made to an existing propeller design and the results and performance of two example propeller blades are given. The inflow velocity at the propeller plane is given special attention and two dimensionless parameters independent of RPM are discussed. Errors in off-design performance are also investigated. 11 refs., 26 figs.

  12. Position Sensor Integral with a Linear Actuator

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Alhorn, Dean C.

    2004-01-01

    A noncontact position sensor has been designed for use with a specific two-dimensional linear electromagnetic actuator. To minimize the bulk and weight added by the sensor, the sensor has been made an integral part of the actuator: that is to say, parts of the actuator structure and circuitry are used for sensing as well as for varying position. The actuator (see Figure 1) includes a C-shaped permanent magnet and an armature that is approximately centered in the magnet gap. The intended function of the actuator is to cause the permanent magnet to translate to, and/or remain at, commanded x and y coordinates, relative to the armature. In addition, some incidental relative motion along the z axis is tolerated but not controlled. The sensor is required to measure the x and y displacements from a nominal central position and to be relatively insensitive to z displacement. The armature contains two sets of electromagnet windings oriented perpendicularly to each other and electrically excited in such a manner as to generate forces in the x,y plane to produce the required motion. Small sensor excitation coils are mounted on the pole tips of the permanent magnet. These coils are excited with a sine wave at a frequency of 20 kHz. This excitation is transformer-coupled to the armature windings. The geometric arrangement of the excitation coils and armature windings is such that the amplitudes of the 20-kHz voltages induced in the armature windings vary nearly linearly with x and y displacements and do not vary significantly with small z displacements. Because the frequency of 20 kHz is much greater than the maximum frequency characteristic of the actuation signals applied to the armature windings, there is no appreciable interference between actuator and sensor functions of the armature windings.

  13. Curved Piezoelectric Actuators for Stretching Optical Fibers

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.

  14. MEMS Actuated Deformable Mirror

    SciTech Connect

    Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M

    2005-11-10

    This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.

  15. Cryogenic Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  16. Propeller Research Tunnel

    NASA Technical Reports Server (NTRS)

    1926-01-01

    This picture shows a general view of the Propeller Research Tunnel engine room under construction. Workmen were installing the two submarine diesel engines that would power the PRT. The room was constructed of concrete with corrugated metal siding and roofing with the intention of making the engine room as fireproof as possible.

  17. Silicone containing solid propellant

    NASA Technical Reports Server (NTRS)

    Ramohalli, K. N. R. (Inventor)

    1980-01-01

    The addition of a small amount, for example 1% by weight, of a liquid silicone oil to a metal containing solid rocket propellant provides a significant reduction in heat transfer to the inert nozzle walls. Metal oxide slag collection and blockage of the nozzle are eliminated and the burning rate is increased by about 5% to 10% thus improving ballistic performance.

  18. New Propellants and Cryofuels

    NASA Technical Reports Server (NTRS)

    Palasezski, Bryan; Sullivan, Neil S.; Hamida, Jaha; Kokshenev, V.

    2006-01-01

    The proposed research will investigate the stability and cryogenic properties of solid propellants that are critical to NASA s goal of realizing practical propellant designs for future spacecraft. We will determine the stability and thermal properties of a solid hydrogen-liquid helium stabilizer in a laboratory environment in order to design a practical propellant. In particular, we will explore methods of embedding atomic species and metallic nano-particulates in hydrogen matrices suspended in liquid helium. We will also measure the characteristic lifetimes and diffusion of atomic species in these candidate cryofuels. The most promising large-scale advance in rocket propulsion is the use of atomic propellants; most notably atomic hydrogen stabilized in cryogenic environments, and metallized-gelled liquid hydrogen (MGH) or densified gelled hydrogen (DGH). The new propellants offer very significant improvements over classic liquid oxygen/hydrogen fuels because of two factors: (1) the high energy-release, and (ii) the density increase per unit energy release. These two changes can lead to significant reduced mission costs and increased payload to orbit weight ratios. An achievable 5 to 10 percent improvement in specific impulse for the atomic propellants or MGH fuels can result in a doubling or tripling of system payloads. The high-energy atomic propellants must be stored in a stabilizing medium such as solid hydrogen to inhibit or delay their recombination into molecules. The goal of the proposed research is to determine the stability and thermal properties of the solid hydrogen-liquid helium stabilizer. Magnetic resonance techniques will be used to measure the thermal lifetimes and the diffusive motions of atomic species stored in solid hydrogen grains. The properties of metallic nano-particulates embedded in hydrogen matrices will also be studied and analyzed. Dynamic polarization techniques will be developed to enhance signal/noise ratios in order to be able to

  19. Reversible switching of hydrogel-actuated nanostructures into complex micropatterns.

    PubMed

    Sidorenko, Alexander; Krupenkin, Tom; Taylor, Ashley; Fratzl, Peter; Aizenberg, Joanna

    2007-01-26

    Responsive behavior, which is intrinsic to natural systems, is becoming a key requirement for advanced artificial materials and devices, presenting a substantial scientific and engineering challenge. We designed dynamic actuation systems by integrating high-aspect-ratio silicon nanocolumns, either free-standing or substrate-attached, with a hydrogel layer. The nanocolumns were put in motion by the "muscle" of the hydrogel, which swells or contracts depending on the humidity level. This actuation resulted in a fast reversible reorientation of the nanocolumns from tilted to perpendicular to the surface. By further controlling the stress field in the hydrogel, the formation of a variety of elaborate reversibly actuated micropatterns was demonstrated. The mechanics of the actuation process have been assessed. Dynamic control over the movement and orientation of surface nanofeatures at the micron and submicron scales may have exciting applications in actuators, microfluidics, or responsive materials.

  20. Electrothermal linear actuator

    NASA Technical Reports Server (NTRS)

    Derr, L. J.; Tobias, R. A.

    1969-01-01

    Converting electric power into powerful linear thrust without generation of magnetic fields is accomplished with an electrothermal linear actuator. When treated by an energized filament, a stack of bimetallic washers expands and drives the end of the shaft upward.

  1. Rotary series elastic actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2012-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  2. Rotary Series Elastic Actuator

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)

    2013-01-01

    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  3. Magnetically Actuated Seal

    NASA Technical Reports Server (NTRS)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  4. Muscle Motion Solenoid Actuator

    NASA Astrophysics Data System (ADS)

    Obata, Shuji

    It is one of our dreams to mechanically recover the lost body for damaged humans. Realistic humanoid robots composed of such machines require muscle motion actuators controlled by all pulling actions. Particularly, antagonistic pairs of bi-articular muscles are very important in animal's motions. A system of actuators is proposed using the electromagnetic force of the solenoids with the abilities of the stroke length over 10 cm and the strength about 20 N, which are needed to move the real human arm. The devised actuators are based on developments of recent modern electro-magnetic materials, where old time materials can not give such possibility. Composite actuators are controlled by a high ability computer and software making genuine motions.

  5. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III

    1994-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The linear proof mass actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (mass, upper housing, lower housing, and center support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operating testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  6. Linear Proof Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, S. E., III

    1995-01-01

    This paper describes the mechanical design, analysis, fabrication, testing, and lessons learned by developing a uniquely designed spaceflight-like actuator. The Linear Proof Mass Actuator (LPMA) was designed to attach to both a large space structure and a ground test model without modification. Previous designs lacked the power to perform in a terrestrial environment while other designs failed to produce the desired accelerations or frequency range for spaceflight applications. Thus, the design for a unique actuator was conceived and developed at NASA Langley Research Center. The basic design consists of four large mechanical parts (Mass, Upper Housing, Lower Housing, and Center Support) and numerous smaller supporting components including an accelerometer, encoder, and four drive motors. Fabrication personnel were included early in the design phase of the LPMA as part of an integrated manufacturing process to alleviate potential difficulties in machining an already challenging design. Operational testing of the LPMA demonstrated that the actuator is capable of various types of load functions.

  7. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  8. Inertial Linear Actuators

    NASA Technical Reports Server (NTRS)

    Laughlin, Darren

    1995-01-01

    Inertial linear actuators developed to suppress residual accelerations of nominally stationary or steadily moving platforms. Function like long-stroke version of voice coil in conventional loudspeaker, with superimposed linear variable-differential transformer. Basic concept also applicable to suppression of vibrations of terrestrial platforms. For example, laboratory table equipped with such actuators plus suitable vibration sensors and control circuits made to vibrate much less in presence of seismic, vehicular, and other environmental vibrational disturbances.

  9. Electrostatic Linear Actuator

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr.; Curry, Kenneth C.

    1990-01-01

    Electrically charged helices attract or repel each other. Proposed electrostatic linear actuator made with intertwined dual helices, which holds charge-bearing surfaces. Dual-helix configuration provides relatively large unbroken facing charged surfaces (relatively large electrostatic force) within small volume. Inner helix slides axially in outer helix in response to voltages applied to conductors. Spiral form also makes components more rigid. Actuator conceived to have few moving parts and to be operable after long intervals of inactivity.

  10. Combustion powered linear actuator

    DOEpatents

    Fischer, Gary J.

    2007-09-04

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  11. Actuation of polypyrrole nanowires

    NASA Astrophysics Data System (ADS)

    Lee, Alexander S.; Peteu, Serban F.; Ly, James V.; Requicha, Aristides A. G.; Thompson, Mark E.; Zhou, Chongwu

    2008-04-01

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  12. Actuation of polypyrrole nanowires.

    PubMed

    Lee, Alexander S; Peteu, Serban F; Ly, James V; Requicha, Aristides A G; Thompson, Mark E; Zhou, Chongwu

    2008-04-23

    Nanoscale actuators are essential components of the NEMS (nanoelectromechanical systems) and nanorobots of the future, and are expected to become a major area of development within nanotechnology. This paper demonstrates for the first time that individual polypyrrole (PPy) nanowires with diameters under 100 nm exhibit actuation behavior, and therefore can potentially be used for constructing nanoscale actuators. PPy is an electroactive polymer which can change volume on the basis of its oxidation state. PPy-based macroscale and microscale actuators have been demonstrated, but their nanoscale counterparts have not been realized until now. The research reported here answers positively the fundamental question of whether PPy wires still exhibit useful volume changes at the nanoscale. Nanowires with a 50 nm diameter and a length of approximately 6 µm, are fabricated by chemical polymerization using track-etched polycarbonate membranes as templates. Their actuation response as a function of oxidation state is investigated by electrochemical AFM (atomic force microscopy). An estimate of the minimum actuation force is made, based on the displacement of the AFM cantilever.

  13. Hybrid electromechanical actuator and actuation system

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Xu, Tian-Bing (Inventor)

    2008-01-01

    A hybrid electromechanical actuator has two different types of electromechanical elements, one that expands in a transverse direction when electric power is applied thereto and one that contracts in a transverse direction when electric power is applied thereto. The two electromechanical elements are (i) disposed in relation to one another such that the transverse directions thereof are parallel to one another, and (ii) mechanically coupled to one another at least at two opposing edges thereof. Electric power is applied simultaneously to the elements.

  14. The screw propeller

    NASA Astrophysics Data System (ADS)

    Larrabee, E. E.

    1980-07-01

    Marine and air screw propellers are considered in terms of theoretical hydrodynamics as developed by Joukowsky, Prandtl, and Betz. Attention is given to the flow around wings of finite span where spanwise flow exists and where lift and the bound vorticity must all go smoothly to zero at the wing tips. The concept of a trailing vortex sheet made up of infinitesimal line vortexes roughly aligned with the direction of flight is discussed in this regard. Also considered is induced velocity, which tends to convect the sheet downward at every stage in the roll-up process, the vortex theory of propellers and the Betz-Prandtl circulation distribution. The performance of the Gossamer Albatross and of a pedal-driven biplane called the Chrysalis are also discussed.

  15. Propellers and windmills

    SciTech Connect

    Newnham, J.H.

    1983-04-12

    The present invention provides a propeller or windmill blank comprising a planar sheet of material having markings defining, or being shaped to have, a central or hub region and two blades extending in opposite directions along imaginary lines; and wherein the blank has a marking or line of preferential folding inclined to the first mentioned lines which, when the blank is bent therealong, will result in pitch being applied to the blades.

  16. Numerical simulation of shrouded propellers

    NASA Technical Reports Server (NTRS)

    Afjeh, Abdollah A.

    1991-01-01

    A numerical model was developed for the evaluation of the performance characteristics of a shrouded propeller. Using this model, a computational study was carried out to investigate the feasibility of improving the aerodynamic performance of a propeller by encasing it in a shroud. The propeller blade was modeled by a segmented bound vortex positioned along the span of the blade at its quarter-chord-line. The shroud was modeled by a number of discrete vortex rings. Due to the mutual dependence of shroud and propeller vortex strengths and the propeller vortex wake an iterative scheme was employed. Three shroud configurations were considered: a cylindrical and two conical shrouds. The computed performance of the shrouded propeller was compared with that of a free propeller of identical propeller geometry. The numerical results indicated that the cylindrical shroud outperformed the conical shroud configurations for the cases considered. Furthermore, when compared to the free propeller performance, the cylindrical shroud showed a considerable performance enhancement over the free propeller. However, the improvements were found to decrease with an increase in the advance ratio and to virtually diminish at advance ratios of about 2.5.

  17. NASA advanced propeller research

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.; Bober, Lawrence J.

    1988-01-01

    Acoustic and aerodynamic research at NASA Lewis Research Center on advanced propellers is reviewed including analytical and experimental results on both single and counterrotation. Computational tools used to calculate the detailed flow and acoustic fields are described along with wind tunnel tests to obtain data for code verification. Results from two kinds of experiments are reviewed: (1) performance and near field noise at cruise conditions as measured in the NASA Lewis 8- by 6-foot Wind Tunnel; and (2) far field noise and performance for takeoff/approach conditions as measured in the NASA Lewis 9- by 15-foot Anechoic Wind Tunnel. Detailed measurements of steady blade surface pressures are described along with vortex flow phenomena at off-design conditions. Near field noise at cruise is shown to level out or decrease as tip relative Mach number is increased beyond 1.15. Counterrotation interaction noise is shown to be a dominant source at takeoff but a secondary source at cruise. Effects of unequal rotor diameters and rotor-to-rotor spacing on interaction noise are also illustrated. Comparisons of wind tunnel acoustic measurements to flight results are made. Finally, some future directions in advanced propeller research such as swirl recovery vanes, higher sweep, forward sweep, and ducted propellers are discussed.

  18. NASA Advanced Propeller Research

    NASA Technical Reports Server (NTRS)

    Groeneweg, John F.; Bober, Lawrence J.

    1988-01-01

    Acoustic and aerodynamic research at NASA Lewis Research Center on advanced propellers is reviewed including analytical and experimental results on both single and counterrotation. Computational tools used to calculate the detailed flow and acoustic i e l d s a r e described along with wind tunnel tests to obtain data for code verification . Results from two kinds of experiments are reviewed: ( 1 ) performance and near field noise at cruise conditions as measured in the NASA Lewis 8-by 6-Foot Wind Tunnel and ( 2 ) farfield noise and performance for takeoff/approach conditions as measured in the NASA Lewis 9-by 15-Font Anechoic Wind Tunnel. Detailed measurements of steady blade surface pressures are described along with vortex flow phenomena at off design conditions . Near field noise at cruise is shown to level out or decrease as tip relative Mach number is increased beyond 1.15. Counterrotation interaction noise is shown to be a dominant source at take off but a secondary source at cruise. Effects of unequal rotor diameters and rotor-to-rotor spacing on interaction noise a real so illustrated. Comparisons of wind tunnel acoustic measurements to flight results are made. Finally, some future directions in advanced propeller research such as swirl recovery vanes, higher sweep, forward sweep, and ducted propellers are discussed.

  19. Helium Saturation of Liquid Propellants

    NASA Technical Reports Server (NTRS)

    Yavrouian, A. H.; Moran, Clifford M.

    1990-01-01

    The research is in three areas which are: (1) techniques were devised for achieving the required levels of helium (He) saturation in liquid propellants (limited to monomethylhydrazine (MMH) and nitrogen tetroxide (NTO)); (2) the values were evaluated for equilibrium solubilities of He in liquid propellants as currently used in the industry; and (3) the He dissolved in liquid propellants were accurately measured. Conclusions drawn from these studies include: (1) Techniques for dissolving He in liquid propellants depending upon the capabilities of the testing facility (Verification of the quantity of gas dissolved is essential); (2) Until greater accuracy is obtained, the equilibrium solubility values of He in MMH and NTO as cited in the Air Force Propellant Handbooks should be accepted as standard (There are still enough uncertainties in the He saturation values to warrant further basic experimental studies); and (3) The manometric measurement of gas volume from a frozen sample of propellant should be the accepted method for gas analysis.

  20. Study of the supersonic propeller

    NASA Technical Reports Server (NTRS)

    Fabri, Jean; Siestrunck, Raymond

    1953-01-01

    In this paper a propeller having all sections operating at supersonic speeds is designated a supersonic propeller regardless of flight speed. Analyses assume subsonic flight speeds but very high rotational speeds. A very elementary analysis of the efficiency of a jet-propeller system is presented. A propeller analysis based on conventional vortex blade element theory is presented and reduced to a single point method which leads to an expression for optimum advance ratio in terms of hub-tip diameter ratio and airfoil fineness ratio. An expression for propeller efficiency in terms of advance ratio, hub-tip diameter ratio, and airfoil thickness ratio is also presented. Use is made of theoretical airfoil characteristics at supersonic speeds. A study of blade section interference, blade shock and expansion fields, at supersonic section speeds is presented. An example taken indicates that an efficiency of seventy percent can be obtained with a propeller having a tip Mach number of 2.3.

  1. Performance optimization of marine propellers

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Sup; Choi, Young-Dal; Ahn, Byoung-Kwon; Shin, Myoung-Sup; Jang, Hyun-Gil

    2010-12-01

    Recently a Wide Chord Tip (WCT) propeller has been developed and applied to a commercial ship by STX Offshore & Shipbuilding. It is reported that the WCT propeller significantly reduces pressure fluctuations and also ship's noise and vibration. On the sea trial, vibration magnitude in the accommodations at NCR was measured at 0.9mm/sec which is only 10% of international allowable magnitude of vibration (9mm/sec). In this paper, a design method for increasing performance of the marine propellers including the WCT propeller is suggested. It is described to maximize the performance of the propeller by adjusting expanded areas of the propeller blade. Results show that efficiency can be increased up to over 2% through the suggested design method.

  2. Digital Actuator Technology

    SciTech Connect

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst

    2014-09-01

    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator

  3. 14 CFR 23.905 - Propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propellers. 23.905 Section 23.905... Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated. (c) Each featherable...

  4. 14 CFR 23.905 - Propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propellers. 23.905 Section 23.905... Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated. (c) Each featherable...

  5. 14 CFR 23.905 - Propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propellers. 23.905 Section 23.905... Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated. (c) Each featherable...

  6. 14 CFR 23.905 - Propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propellers. 23.905 Section 23.905... Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated. (c) Each featherable...

  7. 14 CFR 35.22 - Feathering propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Feathering propellers. 35.22 Section 35.22... STANDARDS: PROPELLERS Design and Construction § 35.22 Feathering propellers. (a) Feathering propellers are... feathering and unfeathering limitations must be documented in the appropriate manuals. (b) Propeller...

  8. 14 CFR 35.22 - Feathering propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Feathering propellers. 35.22 Section 35.22... STANDARDS: PROPELLERS Design and Construction § 35.22 Feathering propellers. (a) Feathering propellers are... feathering and unfeathering limitations must be documented in the appropriate manuals. (b) Propeller...

  9. 14 CFR 35.22 - Feathering propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Feathering propellers. 35.22 Section 35.22... STANDARDS: PROPELLERS Design and Construction § 35.22 Feathering propellers. (a) Feathering propellers are... feathering and unfeathering limitations must be documented in the appropriate manuals. (b) Propeller...

  10. 14 CFR 35.22 - Feathering propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Feathering propellers. 35.22 Section 35.22... STANDARDS: PROPELLERS Design and Construction § 35.22 Feathering propellers. (a) Feathering propellers are... feathering and unfeathering limitations must be documented in the appropriate manuals. (b) Propeller...

  11. 14 CFR 23.905 - Propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propellers. 23.905 Section 23.905... Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the limits for which the propeller is certificated. (c) Each featherable...

  12. 14 CFR 35.22 - Feathering propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Feathering propellers. 35.22 Section 35.22... STANDARDS: PROPELLERS Design and Construction § 35.22 Feathering propellers. (a) Feathering propellers are... feathering and unfeathering limitations must be documented in the appropriate manuals. (b) Propeller...

  13. A biomimetic robotic jellyfish (Robojelly) actuated by shape memory alloy composite actuators.

    PubMed

    Villanueva, Alex; Smith, Colin; Priya, Shashank

    2011-09-01

    An analysis is conducted on the design, fabrication and performance of an underwater vehicle mimicking the propulsion mechanism and physical appearance of a medusa (jellyfish). The robotic jellyfish called Robojelly mimics the morphology and kinematics of the Aurelia aurita species. Robojelly actuates using bio-inspired shape memory alloy composite actuators. A systematic fabrication technique was developed to replicate the essential structural features of A. aurita. Robojelly's body was fabricated from RTV silicone having a total mass of 242 g and bell diameter of 164 mm. Robojelly was able to generate enough thrust in static water conditions to propel itself and achieve a proficiency of 0.19 s(-1) while the A. aurita achieves a proficiency of around 0.25 s(-1). A thrust analysis based on empirical measurements for a natural jellyfish was used to compare the performance of the different robotic configurations. The configuration with best performance was a Robojelly with segmented bell and a passive flap structure. Robojelly was found to consume an average power on the order of 17 W with the actuators not having fully reached a thermal steady state. PMID:21852714

  14. Composite propellant combustion modeling studies

    NASA Technical Reports Server (NTRS)

    Ramohalli, K.

    1977-01-01

    A review is presented of theoretical and experimental studies of composite propellant combustion. The theoretical investigations include a model of the combustion of a nonmetallized ammonium perchlorate (AP) propellant (noting time scales for vapor-phase combustion and the condensed phase) and response functions in pressure-coupled oscillations. The experimental studies are discussed with reference to scale-modeling apparatus, flame standoff distance versus velocity as a function of pressure, and results from T-burner firings of a nonmetallized AP/polysulfide propellant. Research applications including problems with nitramine propellants, the feasibility of stop-restart rockets with salt quench, and combustion problems in large boosters are outlined.

  15. Propeller Analysis from Experimental Data

    NASA Technical Reports Server (NTRS)

    Stickle, George W; Crigler, John L

    1941-01-01

    The operation of the propeller is analyzed by the use of the distribution of forces along the radius, combined with theoretical equations. The data were obtained in the NACA 20-foot wind tunnel on a 4-foot-diameter, two-blade propeller, operating in front of four body shapes, ranging from a small shaft to support the propeller to conventional NACA cowling. A method of estimating the axial and the rotational energy in the wake as a fractional part of the propeller power is given. A knowledge of the total thrust and torque is necessary for the estimation.

  16. Resonance vibrations of aircraft propellers

    NASA Technical Reports Server (NTRS)

    Liebers, Fritz

    1932-01-01

    On the basis of the consideration of various possible kinds of propeller vibrations, the resonance vibrations caused by unequal impacts of the propeller blades appear to be the most important. Their theoretical investigation is made by separate analysis of torsional and bending vibrations. This method is justified by the very great difference in the two natural frequencies of aircraft propeller blades. The calculated data are illustrated by practical examples. Thereby the observed vibration phenomenon in the given examples is explained by a bending resonance, for which the bending frequency of the propeller is equal to twice the revolution speed.

  17. A hybrid actuated microrobot using an electromagnetic field and flagellated bacteria for tumor-targeting therapy.

    PubMed

    Li, Donghai; Choi, Hyunchul; Cho, Sunghoon; Jeong, Semi; Jin, Zhen; Lee, Cheong; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-08-01

    In this paper, we propose a new concept for a hybrid actuated microrobot for tumor-targeting therapy. For drug delivery in tumor therapy, various electromagnetic actuated microrobot systems have been studied. In addition, bacteria-based microrobot (so-called bacteriobot), which use tumor targeting and the therapeutic function of the bacteria, has also been proposed for solid tumor therapy. Compared with bacteriobot, electromagnetic actuated microrobot has larger driving force and locomotive controllability due to their position recognition and magnetic field control. However, because electromagnetic actuated microrobot does not have self-tumor targeting, they need to be controlled by an external magnetic field. In contrast, the bacteriobot uses tumor targeting and the bacteria's own motility, and can exhibit self-targeting performance at solid tumors. However, because the propulsion forces of the bacteria are too small, it is very difficult for bacteriobot to track a tumor in a vessel with a large bloodstream. Therefore, we propose a hybrid actuated microrobot combined with electromagnetic actuation in large blood vessels with a macro range and bacterial actuation in small vessels with a micro range. In addition, the proposed microrobot consists of biodegradable and biocompatible microbeads in which the drugs and magnetic particles can be encapsulated; the bacteria can be attached to the surface of the microbeads and propel the microrobot. We carried out macro-manipulation of the hybrid actuated microrobot along a desired path through electromagnetic field control and the micro-manipulation of the hybrid actuated microrobot toward a chemical attractant through the chemotaxis of the bacteria. For the validation of the hybrid actuation of the microrobot, we fabricated a hydrogel microfluidic channel that can generate a chemical gradient. Finally, we evaluated the motility performance of the hybrid actuated microrobot in the hydrogel microfluidic channel. We expect

  18. A hybrid actuated microrobot using an electromagnetic field and flagellated bacteria for tumor-targeting therapy.

    PubMed

    Li, Donghai; Choi, Hyunchul; Cho, Sunghoon; Jeong, Semi; Jin, Zhen; Lee, Cheong; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-08-01

    In this paper, we propose a new concept for a hybrid actuated microrobot for tumor-targeting therapy. For drug delivery in tumor therapy, various electromagnetic actuated microrobot systems have been studied. In addition, bacteria-based microrobot (so-called bacteriobot), which use tumor targeting and the therapeutic function of the bacteria, has also been proposed for solid tumor therapy. Compared with bacteriobot, electromagnetic actuated microrobot has larger driving force and locomotive controllability due to their position recognition and magnetic field control. However, because electromagnetic actuated microrobot does not have self-tumor targeting, they need to be controlled by an external magnetic field. In contrast, the bacteriobot uses tumor targeting and the bacteria's own motility, and can exhibit self-targeting performance at solid tumors. However, because the propulsion forces of the bacteria are too small, it is very difficult for bacteriobot to track a tumor in a vessel with a large bloodstream. Therefore, we propose a hybrid actuated microrobot combined with electromagnetic actuation in large blood vessels with a macro range and bacterial actuation in small vessels with a micro range. In addition, the proposed microrobot consists of biodegradable and biocompatible microbeads in which the drugs and magnetic particles can be encapsulated; the bacteria can be attached to the surface of the microbeads and propel the microrobot. We carried out macro-manipulation of the hybrid actuated microrobot along a desired path through electromagnetic field control and the micro-manipulation of the hybrid actuated microrobot toward a chemical attractant through the chemotaxis of the bacteria. For the validation of the hybrid actuation of the microrobot, we fabricated a hydrogel microfluidic channel that can generate a chemical gradient. Finally, we evaluated the motility performance of the hybrid actuated microrobot in the hydrogel microfluidic channel. We expect

  19. Torsional Ratcheting Actuating System

    SciTech Connect

    BARNES,STEPHEN MATTHEW; MILLER,SAMUEL L.; RODGERS,M. STEVEN; BITSIE,FERNANDO

    2000-01-24

    A new type of surface micromachined ratcheting actuation system has been developed at the Microelectronics Development Laboratory at Sandia National Laboratories. The actuator uses a torsional electrostatic comb drive that is coupled to an external ring gear through a ratcheting scheme. The actuator can be operated with a single square wave, has minimal rubbing surfaces, maximizes comb finger density, and can be used for open-loop position control. The prototypes function as intended with a minimum demonstrated operating voltage of 18V. The equations of motion are developed for the torsional electrostatic comb drive. The resonant frequency, voltage vs. displacement and force delivery characteristics are predicted and compared with the fabricated device's performance.

  20. Actuating critical care therapeutics.

    PubMed

    Stone, David J; Csete, Marie

    2016-10-01

    Viewing the intensive care unit (ICU) as a control system with inputs (patients) and outputs (outcomes), we focus on actuation (therapies) of the system and how to enhance our understanding of status of patients and their trajectory in the ICU. To incorporate the results of these analytics meaningfully, we feel that a reassessment of predictive scoring systems and of ways to optimally characterize and display the patient's "state space" to clinicians is important. Advances in sensing (diagnostics) and computation have not yet led to significantly better actuation, and so we focus on ways that data can be used to improve actuation in the ICU, in particular by following therapeutic burden along with disease severity. This article is meant to encourage discussion about how the critical care community can best deal with the data they see each day, and prepare for recommendations that will inevitably arise from application of major federal and state initiatives in big data analytics and precision medicine.

  1. 78 FR 41283 - Airworthiness Directives; Dowty Propellers Propellers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... (75 FR 51656, August 23, 2010), and adding the following new AD: 2010-17-11R1 Dowty Propellers... (75 FR 51656, August 23, 2010). (c) Applicability This AD applies to Dowty Propellers R408/6-123-F/17... to revise AD 2010-17-11, Amendment 39-16403 (75 FR 51656, August 23, 2010). That AD applies to...

  2. 78 FR 9005 - Airworthiness Directives; Dowty Propellers Propellers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-07

    ... AD Was Issued Since we issued AD 2010-17-11 (75 FR 51656, August 23, 2010), Dowty Propellers... 39-16403 (75 FR 51656, August 23, 2010), and adding the following new AD: Dowty Propellers (formerly.... Discussion On August 5, 2010, we issued AD 2010-17-11, Amendment 39-16403 (75 FR 51656, August 23, 2010),...

  3. 78 FR 18255 - Airworthiness Directives; Hartzell Propeller, Inc. Propellers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ... 12866, (2) Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Hartzell Propeller, Inc. Propellers AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...

  4. Hydraulic involute cam actuator

    DOEpatents

    Love, Lonnie J.; Lind, Randall F.

    2011-11-01

    Mechanical joints are provided in which the angle between a first coupled member and a second coupled member may be varied by mechanical actuators. In some embodiments the angle may be varied around a pivot axis in one plane and in some embodiments the angle may be varied around two pivot axes in two orthogonal planes. The joints typically utilize a cam assembly having two lobes with an involute surface. Actuators are configured to push against the lobes to vary the rotation angle between the first and second coupled member.

  5. Fault tolerant linear actuator

    DOEpatents

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  6. Propeller blade retention system

    NASA Technical Reports Server (NTRS)

    Elston, III, Sidney B. (Inventor); Simon, III, Victor H. (Inventor); Tseng, Wu-Yang (Inventor); Butler, Lawrence (Inventor)

    1993-01-01

    The invention concerns the mounting of propeller blades to a ring-shaped rotor. The blades are of the variable pitch type, and the shank of each blade extends through a respective hole in the rotor. Each hole contains an annular shelf which is fastened to the wall of the hole and surrounds each shank. Each shank bears a pair of bearing races which sandwich the annular shelf in order to connect the blade to the rotor. Bearing rollers are positioned between the annular shelf and the bearing races.

  7. Applications of dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Pelrine, Ron; Sommer-Larsen, Peter; Kornbluh, Roy D.; Heydt, Richard; Kofod, Guggi; Pei, Qibing; Gravesen, Peter

    2001-07-01

    Dielectric elastomer actuators, based on the field-induced deformation of elastomeric polymers with compliant electrodes, can produce a large strain response, combined with a fast response time and high electromechanical efficiency. This unique performance, combined with other factors such as low cost, suggests many potential applications, a wide range of which are under investigation. Applications that effectively exploit the properties of dielectric elastomers include artificial muscle actuators for robots; low-cost, lightweight linear actuators; solid- state optical devices; diaphragm actuators for pumps and smart skins; acoustic actuators; and rotary motors. Issues that may ultimately determine the success or failure of the actuation technology for specific applications include the durability of the actuator, the performance of the actuator under load, operating voltage and power requirements, and electronic driving circuitry, to name a few.

  8. A power-autonomous self-rolling wheel using ionic and capacitive actuators

    NASA Astrophysics Data System (ADS)

    Must, Indrek; Kaasik, Toomas; Baranova, Inna; Johanson, Urmas; Punning, Andres; Aabloo, Alvo

    2015-04-01

    Ionic electroactive polymer (IEAP) laminates are often considered as perspective actuator technology for mobile robotic appliances; however, only a few real proof-of-concept-stage robots have been built previously, a majority of which are dependent on an off-board power supply. In this work, a power-autonomous robot, propelled by four IEAP actuators having carbonaceous electrodes, is constructed. The robot consists of a light outer section in the form of a hollow cylinder, and a heavy inner section, referred to as the rim and the hub, respectively. The hub is connected to the rim using IEAP actuators, which form `spokes' of variable length. The effective length of the spokes is changed via charging and discharging of the capacitive IEAP actuators and a change in the effective lengths of the spokes eventuate in a rolling motion of the robot. The constructed IEAP robot takes advantage of the distinctive properties of the IEAP actuators. The IEAP actuators transform the geometry of the whole robot, while being soft and compliant. The low-voltage IEAP actuators in the robot are powered directly from an embedded single-cell lithium-ion battery, with no voltage regulation required; instead, only the input current is regulated. The charging of the actuators is commuted correspondingly to the robot's transitory position using an on-board control electronics. The constructed robot is able to roll for an extended period on a smooth surface. The locomotion of the IEAP robot is analyzed using video recognition.

  9. Phytotreatment of propellant contamination.

    PubMed

    Riefler, R Guy; Medina, Victor F

    2006-05-01

    Nitroglycerine (NG) and 2,4-dinitrotoluene (2,4-DNT) are propellants often found in soil and groundwater at military firing ranges. Because of the need for training with live ammunition, control or cleanup of these contaminants may be necessary for the continued use of these firing ranges. One inexpensive approach for managing sites exposed to these contaminants is the use phytoremedation, particularly using common or native grasses. In this study, the uptake of NG and 2,4-DNT from water by three common grasses, yellow nutsedge (Cyperus escalantus), yellow foxtail (Setaria glauca), and common rush (Juncus effusus), was investigated using hydroponic reactors. Rapid removal from solution by all grasses was observed, with yellow nutsedge removal rates being the highest. NG or 2,4-DNT accumulated in the tissues in all of the plants, except yellow foxtail did not accumulate NG. Higher concentrations were observed in killed roots, demonstrating the presence of plant-based enzymes actively transforming the contaminants. Yellow nutsedge was also grown in 2,4-DNT spiked soil. Significant uptake into the plants roots and leaves was observed and concentrations in the soil decreased rapidly, although 2,4-DNT concentration also decreased in the unplanted controls. In summary, the three grasses tested appear to be good candidates for phytoremediation of propellant contamination.

  10. Recent Advancements in Propellant Densification

    NASA Technical Reports Server (NTRS)

    McNelis, Nancy B.; Tomsik, Thomas M.

    1998-01-01

    Next-generation launch vehicles demand several technological improvements to achieve lower cost and more reliable access to space. One technology area whose performance gains may far exceed others is densified propellants. The ideal rocket engine propellant is characterized by high specific impulse, high density, and low vapor pressure. A propellant combination of liquid hydrogen and liquid oxygen (LH2/LOX) is one of the highest performance propellants, but LH2 stored at standard conditions has a relatively low density and high vapor pressure. Propellant densification can significantly improve this propellant's properties relative to vehicle design and engine performance. Vehicle performance calculations based on an average of existing launch vehicles indicate that densified propellants may allow an increase in payload mass of up to 5 percent. Since the NASA Lewis Research Center became involved with the National Aerospace Plane program in the 1980's, it has been leading the way in making densified propellants a viable fuel for next-generation launch vehicles. Lewis researchers have been working to provide a method and critical data for continuous production of densified hydrogen and oxygen.

  11. 21 CFR 700.23 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.23 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in cosmetics as propellants in self-pressurized containers is prohibited...

  12. 21 CFR 700.23 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.23 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in cosmetics as propellants in self-pressurized containers is prohibited...

  13. 21 CFR 700.23 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.23 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in cosmetics as propellants in self-pressurized containers is prohibited...

  14. 21 CFR 700.23 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.23 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in cosmetics as propellants in self-pressurized containers is prohibited...

  15. 21 CFR 700.23 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.23 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in cosmetics as propellants in self-pressurized containers is prohibited...

  16. "Mighty Worm" Piezoelectric Actuator

    NASA Technical Reports Server (NTRS)

    Bamford, Robert M.; Wada, Ben K.; Moore, Donald M.

    1994-01-01

    "Mighty Worm" piezoelectric actuator used as adjustable-length structural member, active vibrator or vibration suppressor, and acts as simple (fixed-length) structural member when inactive. Load force not applied to piezoelectric element in simple-structural-member mode. Piezoelectric element removed from load path when not in use.

  17. Shape Memory Alloy Actuator

    NASA Technical Reports Server (NTRS)

    Baumbick, Robert J. (Inventor)

    2000-01-01

    The present invention discloses and teaches a unique, remote optically controlled micro actuator particularly suitable for aerospace vehicle applications wherein hot gas, or in the alternative optical energy, is employed as the medium by which shape memory alloy elements are activated. In gas turbine powered aircraft the source of the hot gas may be the turbine engine compressor or turbine sections.

  18. Piezoelectric actuator renaissance

    NASA Astrophysics Data System (ADS)

    Uchino, Kenji

    2015-03-01

    This paper resumes the content of the invited talk of the author, read at the occasion of the International Workshop on Relaxor Ferroelectrics, IWRF 14, held on October 12-16, 2014 in Stirin, Czech Republic. It reviews the recent advances in materials, designing concepts, and new applications of piezoelectric actuators, as well as the future perspectives of this area.

  19. Electromechanical flight control actuator

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The feasibility of using an electromechanical actuator (EMA) as the primary flight control equipment in aerospace flight is examined. The EMA motor design is presented utilizing improved permanent magnet materials. The necessary equipment to complete a single channel EMA using the single channel power electronics breadboard is reported. The design and development of an improved rotor position sensor/tachometer is investigated.

  20. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, James G.

    1999-01-01

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing.

  1. Bistable microelectromechanical actuator

    DOEpatents

    Fleming, J.G.

    1999-02-02

    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing. 49 figs.

  2. Photomechanical actuation in polymer-nanotube composites.

    PubMed

    Ahir, Samit V; Terentjev, Eugene M

    2005-06-01

    For some systems, energy from an external source can trigger changes in the internal state of the structure, leading to a mechanical response much larger than the initial input. The ability to unlock this internal work in a solid-state structure is of key importance for many potential applications. We report a novel phenomenon of photo-induced mechanical actuation observed in a polymer-nanotube composite when exposed to infrared radiation. At small strains the sample tends to expand, when stimulated by photons, by an amount that is orders of magnitude greater than the pristine polymer. Conversely, at larger applied pre-strain, it will contract under identical infrared excitation. The behaviour is modelled as a function of orientational ordering of nanotubes induced by the uniaxial extension. It is thought that no other materials can display this continuously reversible response of so large a magnitude, making rubber nanocomposites important for actuator applications. PMID:15880115

  3. Thermally Actuated Hydraulic Pumps

    NASA Technical Reports Server (NTRS)

    Jones, Jack; Ross, Ronald; Chao, Yi

    2008-01-01

    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  4. Low acid producing solid propellants

    NASA Technical Reports Server (NTRS)

    Bennett, Robert R.

    1995-01-01

    The potential environmental effects of the exhaust products of conventional rocket propellants have been assessed by various groups. Areas of concern have included stratospheric ozone, acid rain, toxicity, air quality and global warming. Some of the studies which have been performed on this subject have concluded that while the impacts of rocket use are extremely small, there are propellant development options which have the potential to reduce those impacts even further. This paper discusses the various solid propellant options which have been proposed as being more environmentally benign than current systems by reducing HCI emissions. These options include acid neutralized, acid scavenged, and nonchlorine propellants. An assessment of the acid reducing potential and the viability of each of these options is made, based on current information. Such an assessment is needed in order to judge whether the potential improvements justify the expenditures of developing the new propellant systems.

  5. Dielectric Actuation of Polymers

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofan

    Dielectric polymers are widely used in a plurality of applications, such as electrical insulation, dielectric capacitors, and electromechanical actuators. Dielectric polymers with large strain deformations under an electric field are named dielectric elastomers (DE), because of their relative low modulus, high elongation at break, and outstanding resilience. Dielectric elastomer actuators (DEA) are superior to traditional transducers as a muscle-like technology: large strains, high energy densities, high coupling efficiency, quiet operation, and light weight. One focus of this dissertation is on the design of DE materials with high performance and easy processing. UV radiation curing of reactive species is studied as a generic synthesis methodology to provide a platform for material scientists to customize their own DE materials. Oligomers/monomers, crosslinkers, and other additives are mixed and cured at appropriate ratios to control the stress-strain response, suppress electromechanical instability of the resulting polymers, and provide stable actuation strains larger than 100% and energy densities higher than 1 J/g. The processing is largely simplified in the new material system by removal of the prestretching step. Multilayer stack actuators with 11% linear strain are demonstrated in a procedure fully compatible with industrial production. A multifunctional DE derivative material, bistable electroactive polymer (BSEP), is invented enabling repeatable rigid-to-rigid deformation without bulky external structures. Bistable actuation allows the polymer actuator to have two distinct states that can support external load without device failure. Plasticizers are used to lower the glass transition temperature to 45 °C. Interpenetrating polymer network structure is established inside the BSEP to suppress electromechanical instability, providing a breakdown field of 194 MV/m and a stable bistable strain as large as 228% with a 97% strain fixity. The application of BSEP

  6. [Actuator placement for active sound and vibration control

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two refereed journal publications and ten talks given at conferences, seminars, and colloquia resulted from research supported by NASA. They are itemized in this report. The two publications were entitled "Reactive Tabu and Search Sensor Selection in Active Structural Acoustic Control Problems" and "Quelling Cabin Noise in Turboprop Aircraft via Active Control." The conference presentations covered various aspects of actuator placement, including location problems, for active sound and vibration control of cylinders, of commuter jets, of propeller driven or turboprop aircraft, and for quelling aircraft cabin or interior noise.

  7. Propellers: Theory and observation

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.

    2007-12-01

    The question on the origin and evolution of planetary rings is one of the prominent unsolved problems of planetary sciences with direct implications for planet-forming processes in preplanetary disks. The recent detection of four propeller-shaped features in Saturn's A ring (Tiscareno et al., 2006) proved the presence of large boulder-sized moonlets in the rings (Spahn & Sremcevic, 2000). Their very existence favors a ring creation in a catastrophic disruption of an icy satellite (Sremcevic et al., 2007) rather than a co-genetic origin with Saturn, since bodies of this size can hardly have accreted inside the rings. Here we will review the current state of theoretical modeling and Cassini observations.

  8. Micarta propellers I : materials

    NASA Technical Reports Server (NTRS)

    Caldwell, F W; Clay, N S

    1924-01-01

    Here, values for tension, compression edgewise of laminations, and transverse flatwise of laminations are given for Micarta made with various kinds of sheet material. The corresponding values for white oak are given for comparison. It was found by destructive and service tests that Micarta made with a good grade of cotton duck will give satisfactory service with most designs. In propellers having detachable blades, it is desirable that the root of the blade be of a small cross section to decrease the weight of the metal hub. Here the use of the special fabric or wood veneer offers advantages due to greater tensile strength. These materials, especially the wood veneer, produce stiffer blades than duck. This is also a value in controllable and reversible pitch designs where it is desirable that the plan form of the blades be symmetrical.

  9. Optimal Navigation of Self-Propelled Colloids in Microstructured Mazes

    NASA Astrophysics Data System (ADS)

    Yang, Yuguang; Bevan, Michael

    Controlling navigation of self-propelled microscopic `robots' subject to random Brownian motion in complex microstructured environments (e.g., porous media, tumor vasculature) is important to many emerging applications (e.g., enhanced oil recovery, drug delivery). In this work, we design an optimal feedback policy to navigate an active self-propelled colloidal rod in complex mazes with various obstacle types. Actuation of the rods is modelled based on a light-controlled osmotic flow mechanism, which produces different propulsion velocities along the rod's long axis. Actuator-parameterized Langevin equations, with soft rod-obstacle repulsive interactions, are developed to describe the system dynamics. A Markov decision process (MDP) framework is used for optimal policy calculations with design goals of colloidal rods reaching target end points in minimum time. Simulations show that optimal MDP-based policies are able to control rod trajectories to reach target regions order-of-magnitudes faster than uncontrolled rods, which diverges as maze complexity increases. An efficient multi-graph based implementation for MDP is also presented, which scales linearly with the maze dimension.

  10. Environmentally compatible solid rocket propellants

    NASA Technical Reports Server (NTRS)

    Jacox, James L.; Bradford, Daniel J.

    1995-01-01

    Hercules' clean propellant development research is exploring three major types of clean propellant: (1) chloride-free formulations (no chlorine containing ingredients), being developed on the Clean Propellant Development and Demonstration (CPDD) contract sponsored by Phillips Laboratory, Edwards Air Force Base, CA; (2) low HCl scavenged formulations (HCl-scavenger added to propellant oxidized with ammonium perchlorate (AP)); and (3) low HCl formulations oxidized with a combination of AN and AP (with or without an HCl scavenger) to provide a significant reduction (relative to current solid rocket boosters) in exhaust HCl. These propellants provide performance approaching that of current systems, with less than 2 percent HCl in the exhaust, a significant reduction (greater than or equal to 70 percent) in exhaust HCl levels. Excellent processing, safety, and mechanical properties were achieved using only readily available, low cost ingredients. Two formulations, a sodium nitrate (NaNO3) scavenged HTPB and a chloride-free hydroxy terminated polyether (HTPE) propellant, were characterized for ballistic, mechanical, and rheological properties. In addition, the hazards properties were demonstrated to provide two families of class 1.3, 'zero-card' propellants. Further characterization is planned which includes demonstration of ballistic tailorability in subscale (one to 70 pound) motors over the range of burn rates required for retrofit into current Hercules space booster designs (Titan 4 SRMU and Delta 2 GEM).

  11. A vacuum-driven peristaltic micropump with valved actuation chambers

    NASA Astrophysics Data System (ADS)

    Cui, Jianguo; Pan, Tingrui

    2011-06-01

    This paper presents a simple peristaltic micropump design incorporated with valved actuation chambers and propelled by a pulsed vacuum source. The vacuum-driven peristaltic micropump offers high pumping rates, low backflow, appreciable tolerance to air bubbles, and minimal destruction to fluid contents. The pumping device, fabricated by laser micromachining and plasma bonding of three polydimethylsiloxane (PDMS) layers, includes a pneumatic network, actuation membranes, and microfluidic channels. As the key to peristaltic motion, the sequential deflection of the elastic membranes is achieved by periodic pressure waveforms (negative) traveling through the pneumatic network, provided by a vacuum source regulated by an electromagnetic valve. This configuration eliminates the complicated control logic typically required in peristaltic motion. Importantly, the valved actuation chambers substantially reduce backflow and improve the pumping rates. In addition, the pneumatic network with negative pressure provides a means to effectively remove air bubbles present in the microflow through the gas-permeable PDMS membrane, which can be highly desired in handling complex fluidic samples. Experimental characterization of the micropump performance has been conducted by controlling the resistance of the pneumatic network, the number of normally closed valves, the vacuum pressure, and the frequency of pressure pulses. A maximal flow rate of 600 µL min-1 has been optimized at the pulsed vacuum frequency of 30 Hz with a vacuum pressure of 50 kPa, which is comparable to that of compressed air-actuated peristaltic micropumps.

  12. Propellant acquisition for single-stage rocket technology

    NASA Astrophysics Data System (ADS)

    Grayson, G.; Distefano, E.

    1993-06-01

    An analytical design approach defines the liquid oxygen (LO2) propellant-acquisition system for the vertical-take-off and vertical-landing DC-X flight test vehicle. The DC-X trajectory includes a rotation maneuver in which the vehicle pitches from a nose-first to a tail-first orientation. The 8-ft diameter LO2 tank accommodates outflow rates as high as 120 lbm/sec, while vehicle drag forces result in a lateral acceleration approaching 25 ft/sq sec during rotation. FLOW-3D computational results show that, without propellant control, these conditions cause the LO2 to slosh within the tank and expose the outlet to ullage gas during the rotation maneuver. Using FLOW 3-D simulations of several baffle configurations, one propellant acquisition concept is selected. In this concept, a simple cone-shaped containment baffle compartmentalizes the tank and an outlet extension offsets the outlet to where the propellant is biased. The final design incorporates a factor of safety greater than 2 resulting in continuous coverage of the outlet by propellant as validated by FLOW-3D simulation.

  13. Casting propellant in rocket engine

    NASA Technical Reports Server (NTRS)

    Roach, J. E.; Froehling, S. C. (Inventor)

    1976-01-01

    A method is described for casting a solid propellant in the casing of a rocket engine having a continuous wall with a single opening which is formed by leaves of a material which melt at a temperature of the propellant and with curved edges concentric to the curvature of the spherical casing. The leaves are inserted into the spherical casing through the opening forming a core having a greater width than the width of the single opening and with curved peripheral edges. The cast propellant forms a solid mass and then heated to melt the leaves and provide a central opening with radial projecting flutes.

  14. The Source of Propeller Noise

    NASA Technical Reports Server (NTRS)

    Ernsthausen, W

    1937-01-01

    A two blade propeller of 40 cm diameter and zero pitch was explored for its noise development; it could be whirled up to 17,000 rpm - i.e., a tip speed of 355 meters/second. To obtain the power loss N(sub m) of the propeller for comparison with the produced acoustical power N(sub A) the engine performance characteristics were measured with and without propeller. The result is the sought-for relation c, that is, curve c' after correction with the engine efficiency.

  15. Electrical Actuation Technology Bridging

    NASA Technical Reports Server (NTRS)

    Hammond, Monica (Compiler); Sharkey, John (Compiler)

    1993-01-01

    This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document.

  16. Solar actuated drain system

    SciTech Connect

    Sarver, G. E.; Worstell, B. W.

    1985-04-30

    A temperature actuated drain system is provided that comprises a siphon that has an inlet end for immersing in a pool of water to be drained from a roof surface and a discharge end communicating with a pressure-responsive one-way valve. A solar actuated enclosed chamber that contains a solar heat energy collector is located on the roof surface and is in open communication with the siphon by means of a tubular member that has its inlet end positioned closely adjacent the bottom of the interior of the chamber. The arrangement causes any appreciable amounts of water that accumulate within the chamber to be discharged from the chamber during the pumping action created by the heating and cooling of air within the chamber.

  17. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, M.A.; Ciarlo, D.R.; Lee, A.P.; Krulevitch, P.A.

    1997-07-08

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The ``micro`` size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed. 22 figs.

  18. Microfabricated therapeutic actuator mechanisms

    DOEpatents

    Northrup, Milton A.; Ciarlo, Dino R.; Lee, Abraham P.; Krulevitch, Peter A.

    1997-01-01

    Electromechanical microstructures (microgrippers), either integrated circuit (IC) silicon-based or precision machined, to extend and improve the application of catheter-based interventional therapies for the repair of aneurysms in the brain or other interventional clinical therapies. These micromechanisms can be specifically applied to release platinum coils or other materials into bulging portions of the blood vessels also known as aneurysms. The "micro" size of the release mechanism is necessary since the brain vessels are the smallest in the body. Through a catheter more than one meter long, the micromechanism located at one end of the catheter can be manipulated from the other end thereof. The microgripper (micromechanism) of the invention will also find applications in non-medical areas where a remotely actuated microgripper or similar actuator would be useful or where micro-assembling is needed.

  19. Microfabricated therapeutic actuators

    DOEpatents

    Lee, Abraham P.; Northrup, M. Allen; Ciarlo, Dino R.; Krulevitch, Peter A.; Benett, William J.

    1999-01-01

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.

  20. Microfabricated therapeutic actuators

    DOEpatents

    Lee, A.P.; Northrup, M.A.; Ciarlo, D.R.; Krulevitch, P.A.; Benett, W.J.

    1999-06-15

    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use. 8 figs.

  1. Automatic rotary valve actuator

    SciTech Connect

    Cook, W.E.

    1985-03-28

    This report describes the design, construction, and operation of a microcomputer-controlled valve actuator for operating test valves requiring rotary motion of the valve stem. An AIM 65 microcomputer, using a FORTH language program, controls an air motor and air clutch mounted within an oven to accomplish testing at elevated temperatures. The valve actuator closes the test valve until a preset torque is reached and then opens the valve to its initial starting point. The number of cycles and extremes of rotation are tallied and printed as the test progresses. Provisions are made to accept remote signals to stop the test and to indicate to a remote device when the test has been stopped.

  2. Scissor thrust valve actuator

    DOEpatents

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

    2006-08-29

    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  3. Dissolution actuated sample container

    DOEpatents

    Nance, Thomas A.; McCoy, Frank T.

    2013-03-26

    A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

  4. Linear mass actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)

    1992-01-01

    A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.

  5. Shape memory alloy actuator

    DOEpatents

    Varma, Venugopal K.

    2001-01-01

    An actuator for cycling between first and second positions includes a first shaped memory alloy (SMA) leg, a second SMA leg. At least one heating/cooling device is thermally connected to at least one of the legs, each heating/cooling device capable of simultaneously heating one leg while cooling the other leg. The heating/cooling devices can include thermoelectric and/or thermoionic elements.

  6. Thermally actuated thermionic switch

    DOEpatents

    Barrus, D.M.; Shires, C.D.

    1982-09-30

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  7. Thermally actuated thermionic switch

    DOEpatents

    Barrus, Donald M.; Shires, Charles D.

    1988-01-01

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  8. Passively actuated valve

    DOEpatents

    Modro, S. Michael; Ougouag, Abderrafi M.

    2005-09-20

    A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

  9. Influence of fuselage on propeller design

    NASA Technical Reports Server (NTRS)

    Troller, Theodor

    1928-01-01

    In the present paper I shall not consider the problem of the best arrangement of airplane and propeller, but only a simple method for designing a propeller for a given arrangement of airplane parts. The inflow to the propeller and hence the efficiency of the propeller is affected most by the fuselage.

  10. Application of theory to propeller design

    NASA Technical Reports Server (NTRS)

    Cox, G. G.; Morgan, W. B.

    1974-01-01

    The various theories concerning propeller design are discussed. The use of digital computers to obtain specific blade shapes to meet appropriate flow conditions is emphasized. The development of lifting-line and lifting surface configurations is analyzed. Ship propulsive performance and basic propeller design considerations are investigated. The characteristics of supercavitating propellers are compared with those of subcavitating propellers.

  11. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller configuration. 35.2 Section 35.2... STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the... design of the propeller to be approved under § 21.31 of this chapter....

  12. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller configuration. 35.2 Section 35.2... STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the... design of the propeller to be approved under § 21.31 of this chapter....

  13. 14 CFR 25.905 - Propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propellers. 25.905 Section 25.905... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.905 Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the...

  14. 14 CFR 25.905 - Propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propellers. 25.905 Section 25.905... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.905 Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the...

  15. 14 CFR 25.905 - Propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propellers. 25.905 Section 25.905... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.905 Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the...

  16. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller configuration. 35.2 Section 35.2... STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the... design of the propeller to be approved under § 21.31 of this chapter....

  17. 14 CFR 25.905 - Propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propellers. 25.905 Section 25.905... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.905 Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the...

  18. 14 CFR 21.129 - Tests: propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Tests: propellers. 21.129 Section 21.129... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.129 Tests: propellers. Each person manufacturing propellers under a type certificate must give each variable pitch propeller an...

  19. 14 CFR 25.905 - Propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propellers. 25.905 Section 25.905... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.905 Propellers. (a) Each propeller must have a type certificate. (b) Engine power and propeller shaft rotational speed may not exceed the...

  20. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller configuration. 35.2 Section 35.2... STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the... design of the propeller to be approved under § 21.31 of this chapter....

  1. 14 CFR 21.129 - Tests: propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tests: propellers. 21.129 Section 21.129... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate Only § 21.129 Tests: propellers. Each person manufacturing propellers under a type certificate only shall give each variable pitch propeller...

  2. 14 CFR 35.2 - Propeller configuration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller configuration. 35.2 Section 35.2... STANDARDS: PROPELLERS General § 35.2 Propeller configuration. The applicant must provide a list of all the... design of the propeller to be approved under § 21.31 of this chapter....

  3. Cylindrical Piezoelectric Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  4. Microelectromechanical (MEM) thermal actuator

    DOEpatents

    Garcia, Ernest J.; Fulcher, Clay W. G.

    2012-07-31

    Microelectromechanical (MEM) buckling beam thermal actuators are disclosed wherein the buckling direction of a beam is constrained to a desired direction of actuation, which can be in-plane or out-of-plane with respect to a support substrate. The actuators comprise as-fabricated, linear beams of uniform cross section supported above the substrate by supports which rigidly attach a beam to the substrate. The beams can be heated by methods including the passage of an electrical current through them. The buckling direction of an initially straight beam upon heating and expansion is controlled by incorporating one or more directional constraints attached to the substrate and proximal to the mid-point of the beam. In the event that the beam initially buckles in an undesired direction, deformation of the beam induced by contact with a directional constraint generates an opposing force to re-direct the buckling beam into the desired direction. The displacement and force generated by the movement of the buckling beam can be harnessed to perform useful work, such as closing contacts in an electrical switch.

  5. Propellant gaging for geostationary satellites

    NASA Astrophysics Data System (ADS)

    Orazietti, A. J.; Orton, G. F.; Schreib, R.

    1986-06-01

    Evaluations were performed to select four gaging concepts for ground tests and low-g tests in the NASA KC-135 aircraft. The selected concepts were an ultrasonic point sensor system, a nucleonic gaging system, an ultrasonic torsional wave guide, and an ultrasonic flowmeter. The first three systems provide a direct measurement of propellant quantity remaining, while the fourth system integrates (totalizes) the propellant flow to the engines and infers propellant remaining based on a known initial propellant load. As a result of successful ground and KC-135 tests, two concepts (the ultrasonic point sensor and nucleonic systems) were selected for orbital test in a Shuttle Get-Away-Special experiment. These systems offer high end-of-life accuracy potential, are nonintrusive (external to the tanks and feedlines), and are low in risk because of their good technology base. The Shuttle Get-Away-Special experiment has been assembled and passed flight certification testing in late April 1986.

  6. Generic Propellants Transfer Unit (GPTU)

    NASA Technical Reports Server (NTRS)

    Cook, Christopher A.

    1992-01-01

    The Generic Propellants Transfer Unit (GPTU) is being designed to support spacecraft liquid propellant operations at the Kennedy Space Center (KSC) and Eastern Test Range (ETR). The GPTU will have a 500 gallon capacity and be Department Of Transportation (DOT) approved for over-the-road transportation of hypergolic propellants. The use of these containers will allow the users to increase efficiency and reduce the following costs: design/construction, transportation (to/from the launch site), propellant transfer operations, and decontamination operations. The user also acquires the flexibility of transporting to an offsite location for processing or storage without obtaining special exemptions or permits. These containers will incorporate their own quantity gaging and temperature sensing systems, and be integrated onto a transport trailer which contains work platforms and a fluid transfer system.

  7. Propeller speed and phase sensor

    NASA Technical Reports Server (NTRS)

    Collopy, Paul D. (Inventor); Bennett, George W. (Inventor)

    1992-01-01

    A speed and phase sensor counterrotates aircraft propellers. A toothed wheel is attached to each propeller, and the teeth trigger a sensor as they pass, producing a sequence of signals. From the sequence of signals, rotational speed of each propeller is computer based on time intervals between successive signals. The speed can be computed several times during one revolution, thus giving speed information which is highly up-to-date. Given that spacing between teeth may not be uniform, the signals produced may be nonuniform in time. Error coefficients are derived to correct for nonuniformities in the resulting signals, thus allowing accurate speed to be computed despite the spacing nonuniformities. Phase can be viewed as the relative rotational position of one propeller with respect to the other, but measured at a fixed time. Phase is computed from the signals.

  8. Propeller aircraft interior noise model

    NASA Technical Reports Server (NTRS)

    Pope, L. D.; Wilby, E. G.; Wilby, J. F.

    1984-01-01

    An analytical model was developed to predict the interior noise of propeller-driven aircraft. The fuselage model is that of a cylinder with a structurally-integral floor. The cabin sidewall is stiffened by stringers and ring frames, and the floor by longitudinal beams. The cabin interior is covered with a sidewall treatments consisting of layers of porous material and an impervious trim septum. Representation of the propeller pressure field is utilized as input data in the form of the propeller noise signature at a series of locations on a grid over the fuselage structure. Results obtained from the analytical model are compared with test data measured by NASA in a scale model cylindrical fuselage excited by a model propeller.

  9. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  10. High power thrust vector actuation

    NASA Astrophysics Data System (ADS)

    Kittock, M. J.

    1993-06-01

    Modern missile programs are frequently favoring electro-mechanical (EM) thrust vector actuation (TVA) over hydraulic for a variety of reasons. However, actuation system performance requirements are not relaxed for EM systems. Thus the development of EM systems with greater power output is required. The configuration of EM actuator studied consists of a DC brushless motor driving a spur gear train, which drives a ballscrew that converts rotary motion to rectilinear motion. This design produces an actuator with high levels of performance in a compact mechanical package. Design for manufacturability and assembly (DFMA) was part of the design process, resulting in an actuator that can be assembled easily and will operate reliably. This paper will discuss the mechanical details of the resultant actuator and report test results on a prototype derivative.

  11. Linear Proof-Mass Actuator

    NASA Technical Reports Server (NTRS)

    Holloway, Sidney E., III; Crossley, Edward A.; Miller, James B.; Jones, Irby W.; Davis, C. Calvin; Behun, Vaughn D.; Goodrich, Lewis R., Sr.

    1995-01-01

    Linear proof-mass actuator (LPMA) is friction-driven linear mass actuator capable of applying controlled force to structure in outer space to damp out oscillations. Capable of high accelerations and provides smooth, bidirectional travel of mass. Design eliminates gears and belts. LPMA strong enough to be used terrestrially where linear actuators needed to excite or damp out oscillations. High flexibility designed into LPMA by varying size of motors, mass, and length of stroke, and by modifying control software.

  12. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  13. Direct drive field actuator motors

    DOEpatents

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  14. Fault-tolerant rotary actuator

    DOEpatents

    Tesar, Delbert

    2006-10-17

    A fault-tolerant actuator module, in a single containment shell, containing two actuator subsystems that are either asymmetrically or symmetrically laid out is provided. Fault tolerance in the actuators of the present invention is achieved by the employment of dual sets of equal resources. Dual resources are integrated into single modules, with each having the external appearance and functionality of a single set of resources.

  15. Experimental aeroacoustic study of a landing gear in the unsteady flow induced by a propeller

    NASA Astrophysics Data System (ADS)

    Chekiri, Rafik

    An aeroacoustic study of a two-strut, two-wheel, nacelle-mounted landing gear was conducted to investigate the effects of an upstream propeller on the radiated noise. The development of a 1:10.8 scale model based on a Bombardier Q400 aircraft, consisting of a propeller, motor, nacelle, and landing gear assembly is discussed. Comparisons are made between cases with and without an actuated upstream propeller. Far-field microphone measurements out of the airstream are presented to characterize the acoustic effects of each model component. The main strut and wheels of the model were equipped with surface-mounted microphones to measure unsteady pressures. It is shown that the noise signature of the landing gear cannot be observed over the tunnel background noise in the far-field. Unsteady surface pressures on the main strut show dominant peaks related to vortex shedding from the drag strut for both steady and unsteady upstream conditions.

  16. Solid propellant environmental issues

    SciTech Connect

    Le, M.D.

    1998-07-01

    The objective of the Solid Propellant Environmental Issues (SPEI) project is to demonstrate environmentally acceptable technologies that will enhance the continued production of solid rocket motors (SRMs) by complying with current and anticipated environmental regulations. Phase 1 of the project identifies current and anticipated environmental regulations that may affect SRMs manufacturing in the future and identify emerging process technologies which comply with these regulations. Phase 2 of the project established a baseline database by fabricating a 363 kg motor using the current manufacturing process. In Phase 3, environmentally acceptable process technologies were evaluated, ranked, and selected for demonstration using criteria developed by the team. The results for Phase 1--3 have previously been presented. This paper will present data obtained to date on Phase 4. In Phase 4, the alternate process technologies were evaluated for compatibility, cleaning effectiveness, and waste minimization/pollution prevention. The best performing candidate for each application area was selected for demonstration. The selected process technologies will be inserted into the baseline manufacturing process from Phase 2. The new manufacturing process will be demonstrated and evaluated through the scale-up and fabrication of two 363 kg solid rocket motors.

  17. Aircraft Propeller Hub Repair

    SciTech Connect

    Muth, Thomas R.; Peter, William H.

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  18. Satellite Propellant Pump Research

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Veres, Joseph P.; Hah, Chunill; Nerone, Anthony L.; Cunningham, Cameron C.; Kraft, Thomas G.; Tavernelli, Paul F.; Fraser, Bryan

    2005-01-01

    NASA Glenn initiated a satellite propellant pump technology demonstration program. The goal was to demonstrate the technologies for a 60 percent efficient pump at 1 gpm flow rate and 500 psia pressure rise. The pump design and analysis used the in-house developed computer codes named PUMPA and HPUMP3D. The requirements lead to a 4-stage impeller type pump design with a tip diameter of 0.54 inches and a rotational speed of 57,000 rpm. Analyses indicated that flow cavitation was not a problem in the design. Since the flow was incompressible, the stages were identical. Only the 2-stage pump was designed, fabricated, assembled, and tested for demonstration. Water was selected as the surrogate fluid for hydrazine in this program. Complete mechanical design including stress and dynamic analyses were conducted. The pump was driven by an electric motor directly coupled to the impellers. Runs up to 57,000 rpm were conducted, where a pressure rise of 200 psia at a flow rate of 0.8 gpm was measured to validate the design effort.

  19. Propellant Management in Booster and Upper Stage Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Fisher, Mark F.

    1997-01-01

    A summary review of some of the technical issues which surround the design of the propulsion systems for Booster and Upper Stage systems are presented. The work focuses on Propellant Geyser, Slosh, and Orientation. A brief description of the concern is given with graphics which help the reader to understand the physics of the situation. The most common solutions to these problems are given with there respective advantages and disadvantages.

  20. Dual-Actuator Active Vibration-Control System

    NASA Technical Reports Server (NTRS)

    Kascak, Albert F.; Kiraly, Louis J.; Montague, Gerald T.; Palazzolo, Alan B.; Manchala, Daniel

    1994-01-01

    Dual-actuator active vibration-control (DAAVC) system is developmental system of type described in "Active Vibration Dampers for Rotating Machinery" (LEW-15427). System features sensors and actuators positioned and oriented at bearings to measure and counteract vibrations of shaft along either of two axes perpendicular to axis of rotation. Effective in damping vibrations of helicopter-engine test stand, making it safer to operate engine at speeds near and above first resonance of engine/test-stand system. Opens new opportunities for engine designers to draw more power from engine, and concept applicable to other rotating machines.

  1. Sensor/Actuator Selection for Gust and Turbulence Control

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.

    1998-01-01

    From aircraft fuselages and space stations to vacuum cleaners and automobiles, active control of noise and/or vibration has come of age. Determining the number of active control devices (e.g. actuators) to be placed and where they are to be placed is the prototypical location problem. However, unlike typical location problems, where the customer is readily identified and is actively engaged in the assessment of the performance of the chosen locations, the customers that active control devices serve are not so easily identified and their impact on system performance issues may be unclear. For example, consider the problem of where to locate actuators to attenuate cabin noise in a propeller driven aircraft. Clearly, the ultimate customers are the passengers who will travel in these aircraft. But to decide whether one set of actuator locations is better than another it is unlikely we will ask passengers to fly in the aircraft and fill out a questionnaire about noise levels. Instead a set of sensors (pseudo-customers) are placed and the system performance of the actuators, as measured by these sensors, is recorded. Hence, we have yet another location problem. How many sensors should there be and where should they be located? In many instances collocation of sensors and actuators is the answer but in other instances it is not. A variety of approaches have been taken to address these sensor/actuator location problems. With regard to damping vibrations in truss structures (space station prototypes) it was formulated a new noxious location problem and generated high-quality solutions with a combination of LP-relaxations and heuristic search procedures. Other related efforts are summarized the actuator location problem for a single frequency interior noise control problem was examined for an idealized aircraft cabin. A tabu search procedure was shown to generate better locations for the actuators than a modal decomposition approach. The model was extended to include multi

  2. Passive orientation apparatus

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Martinez, Michael A.

    2001-01-01

    An apparatus that can return a payload to a known orientation after unknown motion, without requiring external power or complex mechanical systems. The apparatus comprises a faceted cage that causes the system to rest in a stable position and orientation after arbitrary motion. A gimbal is mounted with the faceted cage and holds the payload, allowing the payload to move relative to the stable faceted cage. The payload is thereby placed in a known orientation by the interaction of gravity with the geometry of the faceted cage, the mass of the system, and the motion of the payload and gimbal. No additional energy, control, or mechanical actuation is required. The apparatus is suitable for use in applications requiring positioning of a payload to a known orientation after arbitrary or uncontrolled motion, including remote sensing and mobile robot applications.

  3. Pneumatically actuated micropipetting device

    NASA Astrophysics Data System (ADS)

    Szita, Nicolas; Buser, Rudolf A.

    1998-03-01

    We have realized a valveless micropipetting device with an integrated sensor which can aspirate and dispense liquid volumes without any valves, hence without any reflow or dead volume. With an external pneumatic actuation, we have demonstrated aspirating and dispensing from 190nl of 6 (mu) l of water. Measurements showed a standard deviation of down to 1 percent. An integrated capacitive sensor will allow monitoring of the pressure throughout the pipetting process and detect malfunctions, e.g. clotting of the pipetting tip. It is our intention to use this demonstrated precise aspiration mechanism in combination with a micromachined reaction chamber and a miniaturized optical analysis system.

  4. Lead screw linear actuator

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A linear actuator which can apply high forces is described, which includes a reciprocating rod having a threaded portion engaged by a nut that is directly coupled to the rotor of an electric motor. The nut is connected to the rotor in a manner that minimizes loading on the rotor, by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded rod portion, with an oilcarrying groove in the nut being interrupted.

  5. Actuator operated microvalves

    NASA Technical Reports Server (NTRS)

    Okojie, Robert S. (Inventor)

    2008-01-01

    An actuator operated microvalve and the method of making same is disclosed and claimed. The microvalve comprises a SiC housing which includes a first lower portion and a second upper portion. The lower portion of the SiC housing includes a passageway therethrough, a microvalve seat, and a moveable SiC diaphragm. The SiC diaphragm includes a centrally located boss and radially extending corrugations which may be sinusoidally shaped. The boss of the SiC diaphragm moves and modulates in a range of positions between a closed position wherein the boss interengages said microvalve seat prohibiting communication of fluid through the passageway and a fully open position when the boss is spaced apart from the seat at its maximum permitting communication of fluid through said passageway. The actuator includes a SiC top plate affixed to the boss of the diaphragm and a first electrode and the second upper portion of the SiC housing further includes a second electrode.

  6. A bioinspired soft actuated material.

    PubMed

    Roche, Ellen T; Wohlfarth, Robert; Overvelde, Johannes T B; Vasilyev, Nikolay V; Pigula, Frank A; Mooney, David J; Bertoldi, Katia; Walsh, Conor J

    2014-02-26

    A class of soft actuated materials that can achieve lifelike motion is presented. By embedding pneumatic actuators in a soft material inspired by a biological muscle fibril architecture, and developing a simple finite element simulation of the same, tunable biomimetic motion can be achieved with fully soft structures, exemplified here by an active left ventricle simulator.

  7. Smart actuators with piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Janocha, Hartmut; Jendritza, Daniel J.; Scheer, Peter

    1996-04-01

    Piezoelectric solid-state actuators continue to gain in technical and economic significance for a great variety of applications such as quick fine-positioning tasks, control of structural stability and active noise and vibration control due to the high driving forces, short reaction times and compact construction of these actuators. Microelectronics and signal processing must be combined intelligently to form `smart actuators' in order to do justice to the growing demand for precision, miniaturization, efficiency and cost. Energy transducers with piezoelectric PZT ceramics (PZT: lead-zirconate-titanate) simultaneously possess actuator and sensor capacities. An important requirement for the construction of smart actuators is fulfilled by separating the sensor information (charge approximately external force) from the actuator control quantities (elongation approximately electric field strength). A closed-loop control structure with digital signal processing and a voltage controlled power amplifier were developed to enable nearly load-independent linearization of the actuator's response characteristic (elongation-voltage curve) even under dynamic operating conditions by making use of the `self-sensing' effect and without using extra force or displacement sensors. The effectiveness of the developed approach for realizing smart actuators was verified and specified with the help of a computerized large-signal measurement set-up using a low-voltage piezoelectric ceramic stack as an example.

  8. Bi-stable optical actuator

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  9. Rotary actuator for space applications

    NASA Astrophysics Data System (ADS)

    Andión, J. A.; Burgui, C.; Migliorero, G.

    2005-07-01

    SENER is developing a rotary actuator for space applications. The activity, partially funded under ESA GSTP contract, aims at the design, development and performance testing of an innovative rotary actuator concept for space applications. An engineering model has been manufactured and has been tested to demonstrate the compliance with the requirements specification.

  10. Actuated Hybrid Mirror Telescope

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory; Redding, David; Lowman, Andrew; Cohen, David; Ohara, Catherine

    2005-01-01

    The figure depicts the planned Actuated Hybrid Mirror Telescope (AHMT), which is intended to demonstrate a new approach to the design and construction of wide-aperture spaceborne telescopes for astronomy and Earth science. This technology is also appropriate for Earth-based telescopes. The new approach can be broadly summarized as using advanced lightweight mirrors that can be manufactured rapidly at relatively low cost. More specifically, it is planned to use precise replicated metallic nanolaminate mirrors to obtain the required high-quality optical finishes. Lightweight, dimensionally stable silicon carbide (SiC) structures will support the nanolaminate mirrors in the required surface figures. To enable diffraction- limited telescope performance, errors in surface figures will be corrected by use of mirror-shape-control actuators that will be energized, as needed, by a wave-front-sensing and control system. The concepts of nanolaminate materials and mirrors made from nanolaminate materials were discussed in several previous NASA Tech Briefs articles. Nanolaminates constitute a relatively new class of materials that can approach theoretical limits of stiffness and strength. Nanolaminate mirrors are synthesized by magnetron sputter deposition of metallic alloys and/or compounds on optically precise master surfaces to obtain optical-quality reflector surfaces backed by thin shell structures. As an integral part of the deposition process, a layer of gold that will constitute the reflective surface layer is deposited first, eliminating the need for a subsequent and separate reflective-coating process. The crystallographic textures of the nanolaminate will be controlled to optimize the performance of the mirror. The entire deposition process for making a nanolaminate mirror takes less than 100 hours, regardless of the mirror diameter. Each nanolaminate mirror will be bonded to its lightweight SiC supporting structure. The lightweight nanolaminate mirrors and Si

  11. Erosive burning of solid propellants

    NASA Technical Reports Server (NTRS)

    King, Merrill K.

    1993-01-01

    Presented here is a review of the experimental and modeling work concerning erosive burning of solid propellants (augmentation of burning rate by flow of product gases across a burning surface). A brief introduction describes the motor design problems caused by this phenomenon, particularly for low port/throat area ratio motors and nozzleless motors. Various experimental techniques for measuring crossflow sensitivity of solid propellant burning rates are described, with the conclusion that accurate simulation of the flow, including upstream flow development, in actual motors is important since the degree of erosive burning depends not only on local mean crossflow velocity and propellant nature, but also upon this upstream development. In the modeling area, a brief review of simplified models and correlating equations is presented, followed by a description of more complex numerical analysis models. Both composite and double-base propellant models are reviewed. A second generation composite model is shown to give good agreement with data obtained in a series of tests in which composite propellant composition and heterogeneity (particle size distribution) were systematically varied. Finally, the use of numerical models for the development of erosive burning correlations is described, and a brief discussion of scaling is presented.

  12. Assay of potentially contaminated propellant

    SciTech Connect

    Koster, J.E.; Williams, H.E. III; Scott, W.S.

    1995-02-01

    One of the decontamination and decommissioning projects within DOD is demilitarization of an aging stockpile of munitions. A large portion of the stockpile contains depleted uranium (DU) as an armor piercing core and so these munitions must be assayed for the presence of uranium in other components. The assay method must be fast and preferably easy to implement. Presence of DU is indicated by its alpha decay. The alpha particles in turn produce ions in the ambient air. If a significant fraction of these ions can escape the quantity of propellant, the ions can be detected instead of the alpha particles. As a test of the feasibility of detecting alpha emissions from DU somewhere within a cartridge of propellant, the transmission of ions through layers of real propellant was measured. The propellant is in the form of graphite-coated cylindrical pellets. A 105nun cartridge was modified for use as a pellet chamber. A check source served as an ion source. The ion detector consisted of a grid held at 300V coupled to an ammeter. Results confirm that this is a promising technique for testing the propellant for the presence of DU quickly yet with sensitivity.

  13. Reliability studies of electrostrictive actuators

    SciTech Connect

    Kumar, U.; Randall, M.; Hock, J.; Ritter, A.

    1994-12-31

    Multilayer electrostrictive actuators have numerous applications. Frequently these applications involve harsh mechanical and electrical loads. Furthermore, it is typically expected that these loads be incurred for >10{sup 8} repetitions (ideally for an infinite number of cycles). This paper describes the electrical and electro-mechanical analyses used at AVX Corporation to assess the performance characteristics of multilayer ceramic actuators, and addresses the effects of electro-mechanical cycling on selected device properties. In this study, lead magnesium niobate based multilayer electrostrictive actuators were subjected to a.c. fields at rated device voltage. Capacitance, dissipation factor, displacement vs. voltage, displacement hysteresis, electro-mechanical quality factor, and resonant frequency were monitored as a function of electro-mechanical cycling. The actuators exhibited highly stable displacements throughout the investigation. Changes observed in other properties indicate a possibility of using them as NDE techniques to assess the actuator reliability.

  14. Actuator-valve interface optimization

    SciTech Connect

    Burchett, O.L.; Jones, R.L.

    1986-01-01

    A computer code, Actuator Valve Response (AVR), has been developed to optimize the explosive actuator-valve interface parameters so that the valve plunger velocity is at a maximum when the plunger reaches the valve tubes. The code considers three forces to act on the valve plunger before the plunger reaches the valve tubes. These are the pressure force produced by the actuator, the shear force necessary to shear the seal disks on the actuator and the valve plunger, and the friction force caused by friction between the plunger and the plunger bore. The three forces are modeled by expressions that are explicitly functions of the plunger displacement. A particular actuator-valve combination was analyzed with the computer code AVR with four different combinations of valve plunger seal disk shear strength and initial friction force. (LEW)

  15. Reversible thermosensitive biodegradable polymeric actuators based on confined crystallization.

    PubMed

    Stroganov, Vladislav; Al-Hussein, Mahmoud; Sommer, Jens-Uwe; Janke, Andreas; Zakharchenko, Svetlana; Ionov, Leonid

    2015-03-11

    We discovered a new and unexpected effect of reversible actuation of ultrathin semicrystalline polymer films. The principle was demonstrated on the example of thin polycaprolactone-gelatin bilayer films. These films are unfolded at room temperature, fold at temperature above polycaprolactone melting point, and unfold again at room temperature. The actuation is based on reversible switching of the structure of the hydrophobic polymer (polycaprolactone) upon melting and crystallization. We hypothesize that the origin of this unexpected behavior is the orientation of polycaprolactone chains parallel to the surface of the film, which is retained even after melting and crystallization of the polymer or the "crystallization memory effect". In this way, the crystallization generates a directed force, which causes bending of the film. We used this effect for the design of new generation of fully biodegradable thermoresponsive polymeric actuators, which are highly desirable for bionano-technological applications such as reversible encapsulation of cells and design of swimmers.

  16. Fine-Water-Mist Multiple-Orientation-Discharge Fire Extinguisher

    NASA Technical Reports Server (NTRS)

    Butz, James R.; Turchi, Craig S.; Kimball, Amanda; McKinnon, Thomas; Riedel, Edward

    2010-01-01

    A fine-water-mist fire-suppression device has been designed so that it can be discharged uniformly in any orientation via a high-pressure gas propellant. Standard fire extinguishers used while slightly tilted or on their side will not discharge all of their contents. Thanks to the new design, this extinguisher can be used in multiple environments such as aboard low-gravity spacecraft, airplanes, and aboard vehicles that may become overturned prior to or during a fire emergency. Research in recent years has shown that fine water mist can be an effective alternative to Halons now banned from manufacture. Currently, NASA uses carbon dioxide for fire suppression on the International Space Station (ISS) and Halon chemical extinguishers on the space shuttle. While each of these agents is effective, they have drawbacks. The toxicity of carbon dioxide requires that the crew don breathing apparatus when the extinguishers are deployed on the ISS, and Halon use in future spacecraft has been eliminated because of international protocols on substances that destroy atmospheric ozone. A major advantage to the new system on occupied spacecraft is that the discharged system is locally rechargeable. Since the only fluids used are water and nitrogen, the system can be recharged from stores of both carried aboard the ISS or spacecraft. The only support requirement would be a pump to fill the water and a compressor to pressurize the nitrogen propellant gas. This system uses a gaseous agent to pressurize the storage container as well as to assist in the generation of the fine water mist. The portable fire extinguisher hardware works like a standard fire extinguisher with a single storage container for the agents (water and nitrogen), a control valve assembly for manual actuation, and a discharge nozzle. The design implemented in the proof-of-concept experiment successfully extinguished both open fires and fires in baffled enclosures.

  17. Combustion chemistry of solid propellants

    NASA Technical Reports Server (NTRS)

    Baer, A. D.; Ryan, N. W.

    1974-01-01

    Several studies are described of the chemistry of solid propellant combustion which employed a fast-scanning optical spectrometer. Expanded abstracts are presented for four of the studies which were previously reported. One study of the ignition of composite propellants yielded data which suggested early ammonium perchlorate decomposition and reaction. The results of a study of the spatial distribution of molecular species in flames from uncatalyzed and copper or lead catalyzed double-based propellants support previously published conclusions concerning the site of action of these metal catalysts. A study of the ammonium-perchlorate-polymeric-fuel-binder reaction in thin films, made by use of infrared absorption spectrometry, yielded a characterization of a rapid condensed-phase reaction which is likely important during the ignition transient and the burning process.

  18. Wave energy propelling marine ship

    SciTech Connect

    Kitabayashi, S.

    1982-06-29

    A wave energy propelling marine ship comprises a cylindrical ship body having a hollow space therein for transporting fluid material therewithin, a ship body disposed in or on the sea; a propeller attached to the ship body for the purpose of propelling the marine ship for sailing; a rudder for controlling the moving direction of the marine ship; at least one rotary device which includes a plurality of compartments which are each partitioned into a plurality of water chambers by a plurality of radial plates, and a plurality of water charge and/or discharge ports, wherein wave energy is converted into mechanical energy; and device for adjusting buoyancy of the marine ship so that the rotary device is positioned advantageously on the sea surface.

  19. Electromechanical actuation for thrust vector control applications

    NASA Astrophysics Data System (ADS)

    Roth, Mary Ellen

    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type

  20. Frequency-weighted feedforward control for dynamic compensation in ionic polymer-metal composite actuators

    NASA Astrophysics Data System (ADS)

    Shan, Yingfeng; Leang, Kam K.

    2009-12-01

    Ionic polymer-metal composites (IPMCs) are innovative materials that offer combined sensing and actuating ability in lightweight and flexible package. IPMCs have been exploited in robotics and a wide variety of biomedical devices, for example, as sensors for teleoperation, as actuators for positioning in active endoscopy, as fins for propelling aquatic robots, and as an injector for drug delivery. In the actuation mode, one of the main challenges is precise position control. In particular, IPMC actuators exhibit relaxation behavior and nonlinearities; and at relatively high operating frequencies dynamic effects limit accuracy and positioning bandwidth. A frequency-weighted feedforward controller is designed to account for the IPMC's structural dynamics to enable fast positioning. The control method is applied to a custom-made Nafion-based IPMC actuator. The controller takes into account the magnitude of the control input to avoid generating excessively large voltages which can damage the IPMC actuator. To account for unmodeled effects not captured by the dynamics model, a feedback controller is integrated with the feedforward controller. Experimental results show a significant improvement in the tracking performance when feedforward control is used. For instance, the feedforward controller shows over 75% reduction in the tracking error compared to the case without feedforward compensation. Finally, the integrated feedforward and feedback control system reduces the tracking error to less than 10% for tracking an 18-Hz triangle-like trajectory. Some of the advantages of feedforward control as well as its limitations are also discussed.

  1. T-Slide Linear Actuators

    NASA Technical Reports Server (NTRS)

    Vranish, John

    2009-01-01

    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  2. Free swimming of an internally actuated elastic swimmer

    NASA Astrophysics Data System (ADS)

    Yeh, Peter; Erturk, Alper; Alexeev, Alexander

    2013-11-01

    We use fully coupled three-dimensional simulations to examine the underwater locomotion of an internally powered elastic swimmer. The swimmer is modeled as a thin, rectangular, elastic plate with two sections. The first section is internally powered by an oscillating internal moment that produces bending. The second section, a passive fin, undergoes bending oscillations in response to the actuated section. We measure the forward swimming velocity and performance for our hybrid swimmer. We find that the hybrid swimmer with the passive component swims at a higher velocity than that of a fully actuated one. This is in agreement with experiments involving piezoelectric internally powered swimmers. The experiments have shown that thrust is increased when a passive fin is attached to a fully internally actuated swimmer. We investigate the details of the flow structures and bending pattern of the swimmer and show how they affect the forward motion. The results are useful for designing self-propelling bio-inspired robots with internally powered fins.

  3. RSRM Propellant Grain Geometry Modification

    NASA Technical Reports Server (NTRS)

    Schorr, Andrew A.; Endicott, Joni B.; McCool, Alex (Technical Monitor)

    2000-01-01

    This document is composed of viewgraphs about the RSRM propellant grain geometry modification project, which hopes to improve personnel and system safety by modifying propellant grain geometry to improve structural factors of safety. Using techniques such as Finite Element Analysis to determine blend radii required to reduce localized stresses, and ballistic predictions to ensure that the ballistics, ignition transient and Block Model have not been adversely affected, the project hopes to build and test FSM-10 with a new design, and determine flight effectivity pending successful test evaluation.

  4. Characteristics of Five Propellers in Flight

    NASA Technical Reports Server (NTRS)

    Crowley, J W , Jr; Mixson, R E

    1928-01-01

    This investigation was made for the purpose of determining the characteristics of five full-scale propellers in flight. The equipment consisted of five propellers in conjunction with a VE-7 airplane and a Wright E-2 engine. The propellers were of the same diameter and aspect ratio. Four of them differed uniformly in thickness and pitch and the fifth propeller was identical with one of the other four with exception of a change of the airfoil section. The propeller efficiencies measured in flight are found to be consistently lower than those obtained in model tests. It is probable that this is mainly a result of the higher tip speeds used in the full-scale tests. The results show also that because of differences in propeller deflections it is difficult to obtain accurate comparisons of propeller characteristics. From this it is concluded that for accurate comparisons it is necessary to know the propeller pitch angles under actual operating conditions. (author)

  5. Solid Propellant Grain Structural Integrity Analysis

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The structural properties of solid propellant rocket grains were studied to determine the propellant resistance to stresses. Grain geometry, thermal properties, mechanical properties, and failure modes are discussed along with design criteria and recommended practices.

  6. 78 FR 45052 - Airworthiness Directives; Hartzell Propeller, Inc. Propellers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-26

    ... considered the comment received. Hartzell Propeller, Inc. supports the NPRM (78 FR 18255, dated March 26... specified products. The NPRM published in the Federal Register on March 26, 2013 (78 FR 18255). The NPRM... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will...

  7. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W.; Schively, Dixon P.

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

  8. Actuation performance of cellulose based electro-active papers

    NASA Astrophysics Data System (ADS)

    Kim, Jaehwan; Song, Chunseok; Bae, Seung-Hun

    2005-05-01

    Electro-Active Paper (EAPap) is attractive as an EAP actuator material due to its merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and low power consumption. This paper presents the fabrication and performance test of EAPap actuators. EAPap material has been made from cellulose materials. Cellulose fiber is dissolved into a solution and made into a sheet by using a spin coater. Thin electrodes are deposited on the cellophane sheet to comprise an EAPap. Next the EAPap is made into plate or beam specimens cut along a specific orientation to enhance the actuator performance. The EAPap is clamped on electric power connector and placed in an environmental chamber and the tip displacement of EAPap is measured with laser sensor. Also the blocking force of EAPap sample is measured. The measured force is compared with a theoretical beam model. These measurements are performed under a variety of environmental and input factors including frequency, actuation voltage, temperature and humidity. Characteristics of EAPap in terms of fibrous nature, their crystallinity, and mechanical, physical and electrochemical characteristics are presented.

  9. Stabilization of boundary layer streaks by plasma actuators

    NASA Astrophysics Data System (ADS)

    Riherd, Mark; Roy, Subrata

    2014-03-01

    A flow's transition from laminar to turbulent leads to increased levels of skin friction. In recent years, dielectric barrier discharge actuators have been shown to be able to delay the onset of turbulence in boundary layers. While the laminar to turbulent transition process can be initiated by several different instability mechanisms, so far, only stabilization of the Tollmien-Schlichting path to transition has received significant attention, leaving the stabilization of other transition paths using these actuators less explored. To fill that void, a bi-global stability analysis is used here to examine the stabilization of boundary layer streaks in a laminar boundary layer. These streaks, which are important to both transient and by-pass instability mechanisms, are damped by the addition of a flow-wise oriented plasma body force to the boundary layer. Depending on the magnitude of the plasma actuation, this damping can be up to 25% of the perturbation's kinetic energy. The damping mechanism appears to be due to highly localized effects in the immediate vicinity of the body force, and when examined using a linearized Reynolds-averaged Navier-Stokes energy balance, indicate negative production of the perturbation's kinetic energy. Parametric studies of the stabilization have also been performed, varying the magnitude of the plasma actuator's body force and the spanwise wavenumber of the actuation. Based on these parametric studies, the damping of the boundary layer streaks appears to be linear with respect to the total amount of body force applied to the flow.

  10. Note on the Effects of First-Order Aerodynamic Loads on Propeller Shaft Loads with Emphasis on Counterrotating Propellers

    NASA Technical Reports Server (NTRS)

    Rogallo, Vernon L.; McCloud, John L., III; Yaggy, Paul F.

    1954-01-01

    An investigation of the 1XP excitation of inclined single-rotation propellers has indicated a new concept for determining propeller shaft forces and moments of an inclined propeller. This report presents preliminary results, in particular to the counterrotating propeller.

  11. Fatal propeller injuries: three autopsy case reports.

    PubMed

    Ihama, Yoko; Ninomiya, Kenji; Noguchi, Masamichi; Fuke, Chiaki; Miyazaki, Tetsuji

    2009-10-01

    Most propeller injuries occur at water recreational facilities such as those with provision for water skiing, boat racing, skin and scuba diving. Propeller injuries resulting from nautical accidents can be fatal. The sharp blades of propellers rotating at high speeds cause multiple and serious injuries such as deep laceration, chop wounds, bone fractures and mutilation of extremities. We present the autopsy reports of three people who died after colliding with boat propellers.

  12. Micarta propellers IV : technical methods of design

    NASA Technical Reports Server (NTRS)

    Caldwell, F W; Clay, N S

    1924-01-01

    A description is given of the methods used in design of Micarta propellers. The most direct method for working out the design of a Micarta propeller is to start with the diameter and blade angles of a wooden propeller suited for a particular installation and then to apply one of the plan forms suitable for Micarta propellers. This allows one to obtain the corresponding blade widths and to then use these angles and blade widths for an aerodynamic analysis.

  13. Mechanically Oriented, Low-Curie-Temperature Materials

    NASA Technical Reports Server (NTRS)

    Boltich, Edward B.

    1991-01-01

    Proposed fabrication process produces permanent magnets of greater flux density, intended for use at temperatures far below room temperature. Such magnets parts of electrical motors and other electromechanical actuators operating in cryogenic systems. Performances of actuators increase with flux densities available from their magnets. Based on use of mechanical metallurgical techniques to make oriented magnets of Dy3Al2, because these techniques produce alignments above Curie temperature.

  14. Explosive laser light initiation of propellants

    DOEpatents

    Piltch, M.S.

    1993-05-18

    A improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  15. Explosive laser light initiation of propellants

    DOEpatents

    Piltch, Martin S.

    1993-01-01

    A improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  16. Aerosol propellant interference with clinical mass spectrometers.

    PubMed

    Kharasch, E D; Sivarajan, M

    1991-04-01

    Metered dose inhalers containing halogenated propellants may interfere with mass spectrometer quantitation of halogenated inhalation anesthetics. We identify the propellant(s) in a commercially available metered dose inhaler that caused erroneous mass spectrometer readings. In addition, we identify the causes of different types of interference in different mass spectrometers. PMID:2072131

  17. 21 CFR 801.417 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Chlorofluorocarbon propellants. 801.417 Section... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.417 Chlorofluorocarbon propellants. The use of chlorofluorocarbon in devices as propellants in self-pressurized containers...

  18. 21 CFR 801.417 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Chlorofluorocarbon propellants. 801.417 Section... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.417 Chlorofluorocarbon propellants. The use of chlorofluorocarbon in devices as propellants in self-pressurized containers...

  19. 21 CFR 801.417 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Chlorofluorocarbon propellants. 801.417 Section... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.417 Chlorofluorocarbon propellants. The use of chlorofluorocarbon in devices as propellants in self-pressurized containers...

  20. 21 CFR 300.100 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Chlorofluorocarbon propellants. 300.100 Section 300.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human drugs as propellants in...

  1. 21 CFR 189.191 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Chlorofluorocarbon propellants. 189.191 Section... Generally Prohibited From Direct Addition or Use as Human Food § 189.191 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human food as propellants in self-pressurized containers is...

  2. 21 CFR 801.417 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Chlorofluorocarbon propellants. 801.417 Section... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.417 Chlorofluorocarbon propellants. The use of chlorofluorocarbon in devices as propellants in self-pressurized containers...

  3. 21 CFR 300.100 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Chlorofluorocarbon propellants. 300.100 Section 300.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human drugs as propellants in...

  4. 21 CFR 300.100 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Chlorofluorocarbon propellants. 300.100 Section 300.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human drugs as propellants in...

  5. 21 CFR 801.417 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Chlorofluorocarbon propellants. 801.417 Section... (CONTINUED) MEDICAL DEVICES LABELING Special Requirements for Specific Devices § 801.417 Chlorofluorocarbon propellants. The use of chlorofluorocarbon in devices as propellants in self-pressurized containers...

  6. 21 CFR 300.100 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Chlorofluorocarbon propellants. 300.100 Section 300.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human drugs as propellants in...

  7. 21 CFR 300.100 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Chlorofluorocarbon propellants. 300.100 Section 300.100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human drugs as propellants in...

  8. 21 CFR 189.191 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chlorofluorocarbon propellants. 189.191 Section 189... Generally Prohibited From Direct Addition or Use as Human Food § 189.191 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human food as propellants in self-pressurized containers is...

  9. 21 CFR 189.191 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Chlorofluorocarbon propellants. 189.191 Section... Generally Prohibited From Direct Addition or Use as Human Food § 189.191 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human food as propellants in self-pressurized containers is...

  10. 21 CFR 189.191 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Chlorofluorocarbon propellants. 189.191 Section... Generally Prohibited From Direct Addition or Use as Human Food § 189.191 Chlorofluorocarbon propellants. The use of chlorofluorocarbons in human food as propellants in self-pressurized containers is...

  11. 14 CFR 23.925 - Propeller clearance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the...

  12. 14 CFR 25.929 - Propeller deicing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller deicing. 25.929 Section 25.929... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes... accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b)...

  13. 14 CFR 25.929 - Propeller deicing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller deicing. 25.929 Section 25.929... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes... accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b)...

  14. 14 CFR 25.929 - Propeller deicing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller deicing. 25.929 Section 25.929... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes... accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b)...

  15. 14 CFR 25.925 - Propeller clearance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most...

  16. 14 CFR 23.925 - Propeller clearance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the...

  17. 14 CFR 25.925 - Propeller clearance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most...

  18. 14 CFR 25.925 - Propeller clearance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most...

  19. 14 CFR 23.925 - Propeller clearance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the...

  20. 14 CFR 23.925 - Propeller clearance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the...

  1. 14 CFR 25.925 - Propeller clearance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most...

  2. 14 CFR 25.929 - Propeller deicing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller deicing. 25.929 Section 25.929... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes... accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b)...

  3. 14 CFR 25.925 - Propeller clearance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller clearance. 25.925 Section 25.925... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most...

  4. 14 CFR 23.925 - Propeller clearance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller clearance. 23.925 Section 23.925... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant General § 23.925 Propeller clearance. Unless smaller clearances are substantiated, propeller clearances, with the airplane at the...

  5. 14 CFR 25.929 - Propeller deicing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller deicing. 25.929 Section 25.929... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant General § 25.929 Propeller deicing. (a) For airplanes... accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b)...

  6. Micarta Propellers II : Method of Construction

    NASA Technical Reports Server (NTRS)

    Caldwell, F W; Clay, N S

    1924-01-01

    The methods used in manufacturing Micarta propellers differ considerably from those employed with wood propellers on account of the hardness of the materials. The propellers must be formed accurately to size in a mold and afterwards balanced without the customary trimming of the material from the tips. Described here are the pressing and molding processes, filing, boring, balancing, and curing.

  7. Gear-Driven Turnbuckle Actuator

    NASA Technical Reports Server (NTRS)

    Rivera, Ricky N.

    2010-01-01

    This actuator design allows the extension and contraction of turnbuckle assemblies. It can be operated manually or remotely, and is extremely compact. It is ideal for turnbuckles that are hard to reach by conventional tools. The tool assembly design solves the problem of making accurate adjustments to the variable geometry guide vanes without having to remove and reinstall the actuator system back on the engine. The actuator does this easily by adjusting the length of the turnbuckles while they are still attached to the engine.

  8. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

    1993-10-05

    Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

  9. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, Douglas B.; Shahinpoor, Mohsen; Segalman, Daniel J.; Witkowski, Walter R.

    1993-01-01

    Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

  10. A Study of Fluid Interface Configurations in Exploration Vehicle Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory A.; Asipauskas, Marius; Chen, Yongkang; Weislogel, Mark M.

    2010-01-01

    The equilibrium shape and location of fluid interfaces in spacecraft propellant tanks while in low-gravity is of interest to system designers, but can be challenging to predict. The propellant position can affect many aspects of the spacecraft such as the spacecraft center of mass, response to thruster firing due to sloshing, liquid acquisition, propellant mass gauging, and thermal control systems. We use Surface Evolver, a fluid interface energy minimizing algorithm, to investigate theoretical equilibrium liquid-vapor interfaces for spacecraft propellant tanks similar to those that have been considered for NASA's new class of Exploration vehicles. The choice of tank design parameters we consider are derived from the NASA Exploration Systems Architecture Study report. The local acceleration vector employed in the computations is determined by estimating low-Earth orbit (LEO) atmospheric drag effects and centrifugal forces due to a fixed spacecraft orientation with respect to the Earth or Moon, and rotisserie-type spacecraft rotation. Propellant/vapor interface positions are computed for the Earth Departure Stage and Altair lunar lander descent and ascent stage tanks for propellant loads applicable to LEO and low-lunar orbit. In some of the cases investigated the vapor ullage bubble is located at the drain end of the tank, where propellant management device hardware is often located.

  11. Liquid propellant rocket combustion instability

    NASA Technical Reports Server (NTRS)

    Harrje, D. T.

    1972-01-01

    The solution of problems of combustion instability for more effective communication between the various workers in this field is considered. The extent of combustion instability problems in liquid propellant rocket engines and recommendations for their solution are discussed. The most significant developments, both theoretical and experimental, are presented, with emphasis on fundamental principles and relationships between alternative approaches.

  12. The Propeller and the Frog

    NASA Astrophysics Data System (ADS)

    Pan, Margaret; Chiang, Eugene

    2010-10-01

    "Propellers" in planetary rings are disturbances in ring material excited by moonlets that open only partial gaps. We describe a new type of co-orbital resonance that can explain the observed non-Keplerian motions of propellers. The resonance is between the moonlet underlying the propeller and co-orbiting ring particles downstream of the moonlet where the gap closes. The moonlet librates within the gap about an equilibrium point established by co-orbiting material and stabilized by the Coriolis force. In the limit of small libration amplitude, the libration period scales linearly with the gap azimuthal width and inversely as the square root of the co-orbital mass. The new resonance recalls but is distinct from conventional horseshoe and tadpole orbits; we call it the "frog" resonance, after the relevant term in equine hoof anatomy. For a ring surface density and gap geometry appropriate for the propeller Blériot in Saturn's A ring, our theory predicts a libration period of ~4 years, similar to the ~3.7 year period over which Blériot's orbital longitude is observed to vary. These librations should be subtracted from the longitude data before any inferences about moonlet migration are made.

  13. Novel sequences propel familiar folds.

    PubMed

    Jawad, Zahra; Paoli, Massimo

    2002-04-01

    Recent structure determinations have made new additions to a set of strikingly different sequences that give rise to the same topology. Proteins with a beta propeller fold are characterized by extreme sequence diversity despite the similarity in their three-dimensional structures. Several fold predictions, based in part on sequence repeats thought to match modular beta sheets, have been proved correct.

  14. THE PROPELLER AND THE FROG

    SciTech Connect

    Pan, Margaret; Chiang, Eugene

    2010-10-20

    'Propellers' in planetary rings are disturbances in ring material excited by moonlets that open only partial gaps. We describe a new type of co-orbital resonance that can explain the observed non-Keplerian motions of propellers. The resonance is between the moonlet underlying the propeller and co-orbiting ring particles downstream of the moonlet where the gap closes. The moonlet librates within the gap about an equilibrium point established by co-orbiting material and stabilized by the Coriolis force. In the limit of small libration amplitude, the libration period scales linearly with the gap azimuthal width and inversely as the square root of the co-orbital mass. The new resonance recalls but is distinct from conventional horseshoe and tadpole orbits; we call it the 'frog' resonance, after the relevant term in equine hoof anatomy. For a ring surface density and gap geometry appropriate for the propeller Bleriot in Saturn's A ring, our theory predicts a libration period of {approx}4 years, similar to the {approx}3.7 year period over which Bleriot's orbital longitude is observed to vary. These librations should be subtracted from the longitude data before any inferences about moonlet migration are made.

  15. Propeller dynamic and aeroelastic effects

    NASA Technical Reports Server (NTRS)

    Mccormick, B. W.

    1980-01-01

    Various aspects of propeller blade dynamics are considered including those factors which are exciting the blades and the dynamic response of the blades to the excitations. Methods for treating this dynamic system are described and problems are discussed which may arise with advanced turboprop designs employing thin, swept blades.

  16. Liquid Bismuth Propellant Flow Sensor

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Stanojev, B. J.; Korman, V.

    2007-01-01

    Quantifying the propellant mass flow rate in liquid bismuth-fed electric propulsion systems has two challenging facets. First, the flow sensors must be capable of providing a resolvable measurement at propellant mass flow rates on the order of 10 mg/see with and uncertainty of less that 5%. The second challenge has to do with the fact that the materials from which the flow sensors are fabricated must be capable of resisting any of the corrosive effects associated with the high-temperature propellant. The measurement itself is necessary in order to properly assess the performance (thrust efficiency, Isp) of thruster systems in the laboratory environment. The hotspot sensor[I] has been designed to provide the bismuth propellant mass flow rate measurement. In the hotspot sensor, a pulse of thermal energy (derived from a current pulse and associated joule heating) is applied near the inlet of the sensor. The flow is "tagged" with a thermal feature that is convected downstream by the flowing liquid metal. Downstream, a temperature measurement is performed to detect a "ripple" in the local temperature associated with the passing "hotspot" in the propellant. By measuring the time between the upstream generation and downstream detection of the thermal feature, the flow speed can be calculated using a "time of flight" analysis. In addition, the system can be calibrated by measuring the accumulated mass exiting the system as a-function of time and correlating this with the time it takes the hotspot to convect through the sensor. The primary advantage of this technique is that it doesn't depend on an absolute measurement of temperature but, instead, relies on the observation of thermal features. This makes the technique insensitive to other externally generated thermal fluctuations. In this paper, we describe experiments performed using the hotspot flow sensor aimed at quantifying the resolution of the sensor technology. Propellant is expelled onto an electronic scale to

  17. Enzyme actuated bioresponsive hydrogels

    NASA Astrophysics Data System (ADS)

    Wilson, Andrew Nolan

    Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, model systems may be used which seek to interrogate the system dynamics by uni-variable experimentation and limit confounding phenomena such as: polymer-solute interactions, polymer swelling dynamics and biomolecular reaction-diffusion concerns. To this end, a model system, alpha-chymotrypsin (Cht) (a protease) and a cleavable peptide-chromogen (pro-drug) covalently incorporated into a hydrogel, was investigated to understand the mechanisms of covalent loading and release by enzymatic cleavage in bio-responsive delivery systems. Using EDC and Sulfo-NHS, terminal carboxyl groups of N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a cleavable chromogen, were conjugated to primary amines of a hydrated poly(HEMA)-based hydrogel. Hydrogel discs were incubated in buffered Cht causing enzyme-mediated cleavage of the peptide and concomitant release of the chromophore for monitoring. To investigate substrate loading and the effects of hydrogel morphology on the system, the concentration of the amino groups (5, 10, 20, and 30 mol%) and the cross-linked density (1, 5, 7, 9 and 12 mol%) were independently varied. Loading-Release Efficiency of the chromogen was shown to exhibit a positive relation to increasing amino groups (AEMA). The release rates demonstrated a

  18. Variable Valve Actuation

    SciTech Connect

    Jeffrey Gutterman; A. J. Lasley

    2008-08-31

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of the

  19. Firewater system inadvertent actuation frequencies

    SciTech Connect

    Schroeder, J.A.; Eide, S.A.

    1993-04-01

    This paper presents some recommended generic values for fire protection system inadvertent actuation frequencies. The frequencies are based on actual data from Department of Energy and commercial reactor plant facilities.

  20. Firewater system inadvertent actuation frequencies

    SciTech Connect

    Schroeder, J.A. ); Eide, S.A. )

    1993-01-01

    This paper presents some recommended generic values for fire protection system inadvertent actuation frequencies. The frequencies are based on actual data from Department of Energy and commercial reactor plant facilities.

  1. Hydraulically actuated well shifting tool

    SciTech Connect

    Roth, B.A.

    1992-10-20

    This patent describes a hydraulically actuated shifting tool for actuating a sliding member in a well tool. It comprises: a housing having a hydraulic fluid bore therein; shifting dog means positioned on the housing for movement away and toward the housing; locking dog means positioned on the housing for movement away and toward the body; shifting dog hydraulic actuating means in fluid communication with the bore for causing engagement of the shifting dogs with the sliding member; locking dog hydraulic actuating means in communication with the bore for causing engagement of the locking dogs with the locking means; and hydraulic shifting means in communication with the bore for causing relative movement between the shifting dog means and the locking dog means for shifting the sliding sleeve.

  2. Flexure-based nanomagnetic actuators

    NASA Astrophysics Data System (ADS)

    Vasquez, Daniel James

    Nanometer-scale actuators powered through applied-magnetic fields have been designed, fabricated, and tested. These actuators consist of one or more ferromagnetic elements attached to a mechanical flexure. Two types of flexures were studied including a cantilever beam that is fixed on one end, and free on the other. The free end of the cantilever is attached to a, ferromagnetic element allowing a bending torque to be applied by a magnetic field. The second type of actuator design uses a set of torsion beams that are each anchored on one end, and attached to the magnetic element on the other end. The torsion beams are designed such that the application of a magnetic field will result in a twist along the long axis of the beam with little to no bending. The smallest fabricated and tested device is a cantilever-based ferromagnetic actuator that consists of a single 1.5-mum-long, 338-nm-wide, and 50-nm-thick nickel element, and a 2.2-mum-long, 110-nm-wide, and 30-nm-thick gold cantilever beam. A deflection of over 17° was measured for this actuator, while a similar one with a 10.1-mum long cantilever beam experienced measured deflections up to 57°. Torsion-based ferromagnetic actuators have been fabricated and tested with 110-nm-wide, and 50-rim-thick magnetic elements. Such magnetic elements contain only a single saturated magnetic domain. The ultimate scalability of ferromagnetic actuation is limited by the ability of thermal noise to affect the temporal stability of a nanometer-scale magnet. Theory to describe thermal noise and ultimate scalability of the ferromagnetic actuators has been developed. The size of the ferromagnetic actuators studied in this manuscript are smaller than most plant and animal cells. This enables the possibility of such actuators to manipulate a, living cell on an intracellular level. Other potential applications of such small actuators include MHz, to GHz frequency resonators, and tunable optical filters.

  3. Magnetostrictive Actuators For Cryogenic Applications

    NASA Technical Reports Server (NTRS)

    Dolgin, Benjamin P.

    1996-01-01

    Linear-translation motors containing magnetostrictive actuator elements proposed for use in making fine position adjustments on scientific instruments at temperatures from near absolute zero to room temperature. Actuators produce small increments of linear motion and operate in "set-and-forget" mode in sense they automatically lock themselves against motion when power not applied. Do not consume or dissipate power when stationary. Proposed linear-translation motors also made to produce large maximum displacements.

  4. Sensors, actuators, and smart materials

    NASA Astrophysics Data System (ADS)

    Troiler-McKinstry, S.; Newnham, R. E.

    1993-04-01

    Electroceramic materials are presently noted to have a wide array of sensing and actuating functions which can be incorporated into smart-material designs. The sensor types extend to temperature, piezoelectricity and piezoresistivity, and the presence of oxygen. Attention is given to the prospects for developing composite smart materials that encompass various sensing and actuating functions; these may ultimately reach a level of complexity and sophistication that may be termed 'biomimetric' in its approximation to the functions of the living tissues of organisms.

  5. Effects of Proplet on Propeller Efficiency

    NASA Astrophysics Data System (ADS)

    Xu, J. H.; Song, W. P.; Yang, X. D.

    2011-09-01

    Many studies have proved the validation of winglets on improving aerodynamic efficiency. Similar to winglet, a suitable proplet can improve the efficiency of a propeller. The effect of proplet on propeller performance is investigated in this paper. With a cell-centered finite-volume scheme, Reynolds-Averaged Navier-Stokes (RANS) equations are solved on a chimera grid system to simulate the flow around propeller to obtain the aerodynamic performance. A propeller designed for high altitude at 20 km with a diameter of 6.8 m is used as a baseline propeller. The effect of chord length and incidence angle of proplet tip on 8the efficiency of the propeller are also considered. The simulation results demonstrate that a proper proplet leads to weaker blade tip vortex, which is helpful to improve the efficiency of the propeller.

  6. Large Scale Magnetostrictive Valve Actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A.; Holleman, Elizabeth; Eddleman, David

    2008-01-01

    Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

  7. Explosive actuated valve

    DOEpatents

    Byrne, Kenneth G.

    1983-01-01

    1. A device of the character described comprising the combination of a housing having an elongate bore and including a shoulder extending inwardly into said bore, a single elongate movable plunger disposed in said bore including an outwardly extending flange adjacent one end thereof overlying said shoulder, normally open conduit means having an inlet and an outlet perpendicularly piercing said housing intermediate said shoulder and said flange and including an intermediate portion intersecting and normally openly communicating with said bore at said shoulder, normally closed conduit means piercing said housing and intersecting said bore at a location spaced from said normally open conduit means, said elongate plunger including a shearing edge adjacent the other end thereof normally disposed intermediate both of said conduit means and overlying a portion of said normally closed conduit means, a deformable member carried by said plunger intermediate said flange and said shoulder and normally spaced from and overlying the intermediate portion of said normally open conduit means, and means on the housing communicating with the bore to retain an explosive actuator for moving said plunger to force the deformable member against the shoulder and extrude a portion of the deformable member out of said bore into portions of the normally open conduit means for plugging the same and to effect the opening of said normally closed conduit means by the plunger shearing edge substantially concomitantly with the plugging of the normally open conduit means.

  8. Quick actuating closure

    NASA Technical Reports Server (NTRS)

    White, III, Dorsey E. (Inventor); Updike, deceased, Benjamin T. (Inventor); Allred, Johnny W. (Inventor)

    1989-01-01

    A quick actuating closure for a pressure vessel 80 in which a wedge ring 30 with a conical outer surface 31 is moved forward to force shear blocks 40, with conical inner surfaces 41, radially outward to lock an end closure plug 70 within an opening 81 in the pressure vessel 80. A seal ring 60 and a preload ramp 50 sit between the shear blocks 40 and the end closure plug 70 to provide a backup sealing capability. Conical surfaces 44 and 55 of the preload ramp 50 and the shear blocks 40 interact to force the seal ring 60 into shoulders 73 and 85 in the end closure plug 70 and opening 81 to form a tight seal. The end closure plug 70 is unlocked by moving the wedge ring 30 rearward, which causes T-bars 32 of the wedge ring 30 riding within T -slots 42 of the shear blocks 40 to force them radially inward. The end closure plug 70 is then removed, allowing access to the interior of the pressure vessel 80.

  9. Downhole hydraulic actuated pump

    SciTech Connect

    Roeder, G.K.

    1988-09-06

    This patent describes a downhole hydraulically actuated pump assembly of the type having a main housing within which an engine and pump is enclosed; a connecting rod, an engine piston, a pump plunger, means by which the engine and connecting rod reciprocate the pump plunger and thereby produces fluid; the main housing has a lower end having a formation fluid inlet; and upper end having a power fluid inlet; and, a produced fluid outlet; the plunger divides one marginal end of the housing into upper and lower production chambers; the lower end of the connecting rod is hollow and extends through the plunger into fluid communication with the formation fluid inlet to provide a source of formation fluid for the upper and lower production chambers; a traveling value assembly contained within the plunger and arranged to transfer formation fluid from the hollow rod, through the plunger, and into the upper and lower production chambers, respectively, as the plunger upstrokes and downstrokes; produced fluid valve means by which fluid flows from the upper and lower production chambers and through the produced fluid outlet.

  10. Multiple switch actuator

    DOEpatents

    Beyer, Edward T.

    1976-01-06

    The present invention relates to switches and switch actuating devices to be operated for purposes of arming a bomb or other missile as it is dropped or released from an aircraft. The particular bomb or missile in which this invention is applied is one in which there is a plurality of circuits which are to be armed by the closing of switches upon dropping or releasing of the bomb. The operation of the switches to closed position is normally accomplished by means of a pull-out wire; that is, a wire which is withdrawn from the bomb or missile at the time of release of the bomb, one end of the wire being attached to the aircraft. The conditions to be met are that the arming switches must be positively and surely maintained in open position until the bomb is released and the arming action is effected. The action of the pull-out wire in achieving the arming action must be sure and positive with minimum danger of malfunctioning, jamming or binding.

  11. Development of a novel actuator concept for position control of segmented mirrors of ELT

    NASA Astrophysics Data System (ADS)

    Janssen, H.; Geurink, R.; Teuwen, M.; v. Bree, B.

    2006-06-01

    Currently, a number of astrophysical institutes all over the world are working on the design of Extremely Large Telescopes (ELT). Due to the enormous size of the primary mirror these telescopes make use of segmented mirrors. These segments have to be positioned with respect to each other with nanometer accuracy in spite of all kind of external disturbances such as wind loads, thermal loads, deformation of the base frame, varying orientation with respect to the field of gravity, etc. Janssen Precision Engineering (JPE) developed a revolutionary position actuator called the HiPAC which is able to fulfill the demanding requirements for this kind of actuators. The actuator is based on an integrated system of a pneumatic actuator, an electric voice coil and smart control strategy and has the following features: high positioning accuracy performance due to play-free and frictionless actuation; high reliability and maintenance free operation due to flexure-based frictionless guiding; system behavior is constant in time, because no parts affected by wear are used in the actuator; low cost, because no highly accurate machined parts required to reach high end performance; the position actuator acts as an integrated vibration isolator which isolates the segmented mirrors from external vibrations induced in the telescope frame; In this paper the design, simulation and measurements of the HiPAC actuator will be presented.

  12. Development of a novel actuator concept for position control of segmented mirrors of ELT

    NASA Astrophysics Data System (ADS)

    Janssen, H.; Geurink, R.; Teuwen, M.; v. Bree, B.

    2008-07-01

    Currently, a number of astrophysical institutes all over the world are working on the design of Extremely Large Telescopes (ELT). Due to the enormous size of the primary mirror these telescopes make use of segmented mirrors. These segments have to be positioned with respect to each other with nanometer accuracy in spite of all kind of external disturbances such as wind loads, thermal loads, deformation of the base frame, varying orientation with respect to the field of gravity, etc. Janssen Precision Engineering (JPE) developed a revolutionary position actuator called the HiPAC which is able to fulfill the demanding requirements for this kind of actuators. The actuator is based on an integrated system of a pneumatic actuator, an electric voice coil and smart control strategy and has the following features: high positioning accuracy performance due to play-free and frictionless actuation; high reliability and maintenance free operation due to flexure-based frictionless guiding; system behavior is constant in time, because no parts affected by wear are used in the actuator; low cost, because no highly accurate machined parts required to reach high end performance; the position actuator acts as an integrated vibration isolator which isolates the segmented mirrors from external vibrations induced in the telescope frame; In this paper the design, simulation and measurements of the HiPAC actuator will be presented.

  13. Hydrogel core flexible matrix composite (H-FMC) actuators: theory and preliminary modelling

    NASA Astrophysics Data System (ADS)

    Dicker, M. P. M.; Weaver, P. M.; Rossiter, J. M.; Bond, I. P.

    2014-09-01

    The underlying theory of a new actuator concept based on hydrogel core flexible matrix composites (H-FMC) is presented. The key principle that underlines the H-FMC actuator operation is that the three-dimensional swelling of a hydrogel is partially constrained in order to improve the amount of useful work done. The partial constraint is applied to the hydrogel by a flexible matrix composite (FMC) that minimizes the hydrogel's volume expansion while swelling. This constraint serves to maximize the fixed charge density and resulting osmotic pressure, the driving force behind actuation. In addition, for certain FMC fibre orientations the Poisson's ratio of the anisotropic FMC laminate converts previously unused hydrogel swelling in the radial and circumferential directions into useful axial strains. The potential benefit of the H-FMC concept to hydrogel actuator performance is shown through comparison of force-stroke curves and evaluation of improvements in useful actuation work. The model used to achieve this couples chemical and electrical components, represented with the Nernst-Plank and Poisson equations, as well as a linear elastic mechanical material model, encompassing limited geometric nonlinearities. It is found that improvements in useful actuation work in the order of 1500% over bare hydrogel performance are achieved by the H-FMC concept. A parametric study is also undertaken to determine the effect of various FMC design parameters on actuator free strain and blocking stress. A comparison to other actuator concepts is also included.

  14. Space Shuttle Orbital Maneuvering Subsystem (OMS) Engine Propellant Leakage Ball-Valve Shaft Seals

    NASA Technical Reports Server (NTRS)

    Lueders, Kathy; Buntain, Nick; Fries, Joseph (Technical Monitor)

    1999-01-01

    Evidence of propellant leakage across ball-valve shaft seals has been noted during the disassembly of five flight engines and one test engine at the NASA Lyndon B. Johnson Space Center, White Sands Test Facility. Based on data collected during the disassembly of these five engines, the consequences of propellant leakage across the ball-valve shaft seals can be divided into four primary areas of concern: Damage to the ball-valve pinion shafts, damage to sleeved bearings inside the ball-valve and actuator assemblies, degradation of the synthetic rubber o-rings used in the actuator assemblies, and corrosion and degradation to the interior of the actuator assemblies. The exact time at which leakage across the ball-valve shaft seals occurs has not been determined, however, the leakage most likely occurs during engine firings when, depending on the specification used, ball-valve cavity pressures range as high as 453 to 550 psia. This potential pressure range for the ball-valve cavities greatly exceeds the acceptance leakage test pressure of 332 psia. Since redesign and replacement of the ball-valve shaft seals is unlikely, the near term solution to prevent damage that occurs from shaft-seal leakage is to implement a routine overhaul and maintenance program for engines in the fleet. Recommended repair, verification, and possible preventative maintenance measures are discussed in the paper.

  15. Effects of the acceleration vector on transient burning rate of an aluminized solid propellant.

    NASA Technical Reports Server (NTRS)

    Northam, G. B.

    1971-01-01

    Experimental results concerning the transient burning-rate augmentation of a 16% aluminum polybutadiene acrylic acid (PBAA) propellant burned in a 2-in. web motor at pressure levels from 300 to 1200 psia with centrifugal accelerations from 0 to 140 g. The orientation of the acceleration vector was varied to determine its effect on the transient burning rate. The burning-rate augmentation was strongly dependent on (1) acceleration level, (2) propellant distance burned (or burn time), and (3) orientation of the acceleration vector with respect to the burning surface. This transient rate augmentation resulted from the retention of molten metallic residue on the burning surface by the normal acceleration loading. The presence of the residue altered the combustion zone heat transfer and caused increased localized burning rates, as evidenced by the pitted propellant surfaces that were observed from extinction tests conducted at various acceleration levels.

  16. Design of an innovative dielectric elastomer actuator for space applications

    NASA Astrophysics Data System (ADS)

    Branz, Francesco; Sansone, Francesco; Francesconi, Alessandro

    2014-03-01

    The capability of Dielectric Elastomers to show large deformations under high voltage loads has been deeply investigated to develop a number of actuators concepts. From a space systems point of view, the advantages introduced by this class of smart materials are considerable and include high conversion efficiency, distributed actuation, self-sensing capability, light weight and low cost. This paper focuses on the design of a solid-state actuator capable of high positioning resolution. The use of Electroactive Polymers makes this device interesting for space mechanisms applications, such as antenna and sensor pointing, solar array orientation, attitude control, adaptive structures and robotic manipulators. In particular, such actuation suffers neither wear, nor fatigue issues and shows highly damped vibrations, thus requiring no maintenance and transferring low disturbance to the surrounding structures. The main weakness of this actuator is the relatively low force/torque values available. The proposed geometry allows two rotational degrees of freedom, and simulations are performed to measure the expected instant angular deflection at zero load and the stall torque of the actuator under a given high voltage load. Several geometric parameters are varied and their influence on the device behaviour is studied. Simplified relations are extrapolated from the numerical results and represent useful predicting tools for design purposes. Beside the expected static performances, the dynamic behaviour of the device is also assessed and the input/output transfer function is estimated. Finally, a prototype design for laboratory tests is presented; the experimental activity aims to validate the preliminary results obtained by numerical analysis.

  17. Experimental research on air propellers

    NASA Technical Reports Server (NTRS)

    Durand, William F

    1918-01-01

    The purposes of the experimental investigation on the performance of air propellers described in this report are as follows: (1) the development of a series of design factors and coefficients drawn from model forms distributed with some regularity over the field of air-propeller design and intended to furnish a basis of check with similar work done in other aerodynamic laboratories, and as a point of departure for the further study of special or individual types and forms; (2) the establishment of a series of experimental values derived from models and intended for later use as a basis for comparison with similar results drawn from certain selected full-sized forms and tested in free flight.

  18. Processing solid propellants for recycling

    SciTech Connect

    Whinnery, L.L.; Griffiths, S.K.; Handrock, J.L.; Lipkin, J.

    1994-05-01

    Rapid evolution in the structure of military forces worldwide is resulting in the retirement of numerous weapon systems. Many of these systems include rocket motors containing highly energetic propellants based on hazardous nitrocellulose/nitroglycerin (NC/NG) mixtures. Even as the surplus quantities of such material increases, however, current disposal methods -- principally open burning and open detonation (OB/OD) -- are coming under close scrutiny from environmental regulators. Environmentally conscious alternatives to disposal of propellant and explosives are thus receiving renewed interest. Recycle and reuse alternatives to OB/OD appear particularly attractive because some of the energetic materials in the inventories of surplus weapon systems represent potentially valuable resources to the commercial explosives and chemical industries. The ability to reclaim such resources is therefore likely to be a key requirement of any successful technology of the future in rocket motor demilitarization. This document consists of view graphs from the poster session.

  19. Propellant resupply of orbiting spacecraft

    NASA Technical Reports Server (NTRS)

    Bloznalis, P. J.; Lupien, R.; Sudbay, M.; Dangelo, M.; Perry, B.; Vidal, M.

    1989-01-01

    The technology to transfer safely and easily fluids in microgravity is necessary to extend the duration of future space missions. The absence of gravity in space causes fluids to behave much differently than on Earth, making propellant resupply extremely difficult. The Gamma Ray Observatory (GRO) is one of the satellites being designed for refueling. The GRO's thrusters are fueled by the monopropellant hydrazine that as a vapor is unstable above 200 F. This has a major impact on refueling system design and operation. A system using high pressure gas and flexible diaphragms to transfer propellant from a supply vehicle to the GRO was proposed and designed. A ground-based system utilizing the transfer technique of ullage recompression was built to investigate the process.

  20. Propeller Study. Part 2: the Design of Propellers for Minimum Noise

    NASA Technical Reports Server (NTRS)

    Ormsbee, A. I.; Woan, C. J.

    1977-01-01

    The design of propellers which are efficient and yet produce minimum noise requires accurate determinations of both the flow over the propeller. Topics discussed in relating aerodynamic propeller design and propeller acoustics include the necessary approximations and assumptions involved, the coordinate systems and their transformations, the geometry of the propeller blade, and the problem formulations including the induced velocity, required in the determination of mean lines of blade sections, and the optimization of propeller noise. The numerical formulation for the lifting-line model are given. Some applications and numerical results are included.

  1. Alternate propellant program, phase 1

    NASA Technical Reports Server (NTRS)

    Anderson, F. A.; West, W. R.

    1979-01-01

    Candidate propellant systems for the shuttle booster solid rocket motor (SRM), which would eliminate, or greatly reduce, the amount of HCl produced in the exhaust of the shuttle SRM were investigated. Ammonium nitrate was selected for consideration as the main oxidizer, with ammonium perchlorate and the nitramine, cyclo-tetramethylene-tetranitramine as secondary oxidizers. The amount of ammonium perchlorate used was limited to an amount which would produce an exhaust containing no more than 3% HCl.

  2. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (Inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  3. Self-propelled Leidenfrost droplets.

    PubMed

    Linke, H; Alemán, B J; Melling, L D; Taormina, M J; Francis, M J; Dow-Hygelund, C C; Narayanan, V; Taylor, R P; Stout, A

    2006-04-21

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid. PMID:16712160

  4. Self-Propelled Leidenfrost Droplets

    NASA Astrophysics Data System (ADS)

    Linke, H.; Alemán, B. J.; Melling, L. D.; Taormina, M. J.; Francis, M. J.; Dow-Hygelund, C. C.; Narayanan, V.; Taylor, R. P.; Stout, A.

    2006-04-01

    We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.

  5. Stable electroosmotically driven actuators

    NASA Astrophysics Data System (ADS)

    Sritharan, Deepa; Motsebo, Mylene; Tumbic, Julia; Smela, Elisabeth

    2013-04-01

    We have previously presented "nastic" actuators based on electroosmotic (EO) pumping of fluid in microchannels using high electric fields for potential application in soft robotics. In this work we address two challenges facing this technology: applying EO to meso-scale devices and the stability of the pumping fluid. The hydraulic pressure achieved by EO increases with as 1/d2, where d is the depth of the microchannel, but the flow rate (which determines the stroke and the speed) is proportional to nd, where n is the number of channels. Therefore to get high force and high stroke the device requires a large number of narrow channels, which is not readily achievable using standard microfabrication techniques. Furthermore, for soft robotics the structure must be soft. In this work we present a method of fabricating a three-dimensional porous elastomer to serve as the array of channels based on a sacrificial sugar scaffold. We demonstrate the concept by fabricating small pumps. The flexible devices were made from polydimethylsiloxane (PDMS) and comprise the 3D porous elastomer flanked on either side by reservoirs containing electrodes. The second issue addressed here involves the pumping fluid. Typically, water is used for EO, but water undergoes electrolysis even at low voltages. Since EO takes place at kV, these systems must be open to release the gases. We have recently reported that propylene carbonate (PC) is pumped at a comparable rate as water and is also stable for over 30 min at 8 kV. Here we show that PC is, however, degraded by moisture, so future EO systems must prevent water from reaching the PC.

  6. The LDCM actuator for vibration suppression

    NASA Technical Reports Server (NTRS)

    Ide, Eric N.; Lindner, Douglas K.

    1988-01-01

    A linear dc motor (LDCM) has been proposed as an actuator for the COFS I mast and the COFS program ground test Mini-Mast. The basic principles of operation of the LDCM as an actuator for vibration suppression in large flexible structures are reviewed. Because of force and stroke limitations, control loops are required to stabilize the actuator, which results in a non-standard actuator-plant configuration. A simulation model that includes LDCM actuator control loops and a finite element model of the Mast is described, with simulation results showing the excitation capability of the actuator.

  7. Actuator selection for large space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Ruan, Mifang

    1990-01-01

    The paper discusses the process of selecting the actuator locations and the determination of the required number of actuators for large space structures. The selection is based on the definitions of the degree of controllability, the independence of actuators, and the effectiveness of the individual actuators. An algorithm is developed that can be used for the selection of the essential number of actuators and for finding some defects of the system, such as the insuffiency of the available actuator locations for effective control of the whole system or a too crowded frequency distribution. The efficiency of the algorithm was demonstrated by an application to the Space Station.

  8. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready...

  9. 14 CFR 25.875 - Reinforcement near propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Reinforcement near propellers. 25.875....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must be... propeller. (b) No window may be near the propeller tips unless it can withstand the most severe ice...

  10. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready...

  11. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready...

  12. 14 CFR 25.875 - Reinforcement near propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Reinforcement near propellers. 25.875....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must be... propeller. (b) No window may be near the propeller tips unless it can withstand the most severe ice...

  13. 14 CFR 25.875 - Reinforcement near propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Reinforcement near propellers. 25.875....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must be... propeller. (b) No window may be near the propeller tips unless it can withstand the most severe ice...

  14. 14 CFR 25.875 - Reinforcement near propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Reinforcement near propellers. 25.875....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must be... propeller. (b) No window may be near the propeller tips unless it can withstand the most severe ice...

  15. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready...

  16. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready...

  17. 14 CFR 25.875 - Reinforcement near propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Reinforcement near propellers. 25.875....875 Reinforcement near propellers. (a) Each part of the airplane near the propeller tips must be... propeller. (b) No window may be near the propeller tips unless it can withstand the most severe ice...

  18. Swarm behavior of self-propelled rods and swimming flagella

    NASA Astrophysics Data System (ADS)

    Yang, Yingzi; Marceau, Vincent; Gompper, Gerhard

    2010-09-01

    Systems of self-propelled particles are known for their tendency to aggregate and to display swarm behavior. We investigate two model systems: self-propelled rods interacting via volume exclusion and sinusoidally beating flagella embedded in a fluid with hydrodynamic interactions. In the flagella system, beating frequencies are Gaussian distributed with a nonzero average. These systems are studied by Brownian-dynamics simulations and by mesoscale hydrodynamics simulations, respectively. The clustering behavior is analyzed as the particle density and the environmental or internal noise are varied. By distinguishing three types of cluster-size probability density functions, we obtain a phase diagram of different swarm behaviors. The properties of clusters such as their configuration, lifetime, and average size are analyzed. We find that the swarm behavior of the two systems, characterized by several effective power laws, is very similar. However, a more careful analysis reveals several differences. Clusters of self-propelled rods form due to partially blocked forward motion and are therefore typically wedge shaped. At higher rod density and low noise, a giant mobile cluster appears, in which most rods are mostly oriented toward the center. In contrast, flagella become hydrodynamically synchronized and attract each other; their clusters are therefore more elongated. Furthermore, the lifetime of flagella clusters decays more quickly with cluster size than of rod clusters.

  19. Characterization of electrostatic glass actuators

    NASA Astrophysics Data System (ADS)

    Moser, R.; Wüthrich, R.; Sache, L.; Higuchi, T.; Bleuler, H.

    2003-06-01

    Electrostatic glass actuators are a promising concept for various applications. The use of the interaction between glassy substances and electrostatic fields allows synchronous propulsion akin to the electret actuator. Even though some properties of electrostatic glass motors have been observed and described, a characterization is still missing. The authors would like to present the experimental work leading to the determination of the optimal glass blend and to the optimal electrode pattern in order to maximize the exploitable forces. An analytical model is also presented, satisfactorily close to the measured data. These measurements and models constitute a tool to design electrostatic glass actuators such as, for example, a miniature disk drive, which is presented as one of several promising applications.

  20. Wellhead with hydraulic pump actuator

    SciTech Connect

    Brown, H.D.; Brown, M.A.; Rohling, L.J.

    1984-07-31

    A wellhead assembly especially suited for oil wells has a wide working pressure range and employs three components which fit together to seal the well casing, hold the tubing against high wellhead pressures, and provide a connection to the tubing through which the sucker rods are operated. The primary casing seal is formed by the mating contact of metal surfaces that are not subject to deterioration. The actuator for the subsurface pump is a vertically disposed hydraulic cylinder unit aligned with the sucker rods and forming the uppermost section of an elongated cylindrical housing, which also has a lowermost section on the wellhead that provides the outlets for the fluid pumped from the well, and an intermediate, control section that contains a spool valve for controlling the hydraulic actuator. The spool is shifted by the piston and rod of the hydraulic actuator at the upper and lower limits of their stroke to thereby reciprocate the sucker rods and operate the subsurface pump.

  1. A Parylene Bellows Electrochemical Actuator

    PubMed Central

    Li, Po-Ying; Sheybani, Roya; Gutierrez, Christian A.; Kuo, Jonathan T. W.; Meng, Ellis

    2011-01-01

    We present the first electrochemical actuator with Parylene bellows for large-deflection operation. The bellows diaphragm was fabricated using a polyethylene-glycol-based sacrificial molding technique followed by coating in Parylene C. Bellows were mechanically characterized and integrated with a pair of interdigitated electrodes to form an electrochemical actuator that is suitable for low-power pumping of fluids. Pump performance (gas generation rate and pump efficiency) was optimized through a careful examination of geometrical factors. Overall, a maximum pump efficiency of 90% was achieved in the case of electroplated electrodes, and a deflection of over 1.5 mm was demonstrated. Real-time wireless operation was achieved. The complete fabrication process and the materials used in this actuator are bio-compatible, which makes it suitable for biological and medical applications. PMID:21318081

  2. Electrochemical corrosion studies in low conductivity propellants

    NASA Technical Reports Server (NTRS)

    Blue, G. D.; Moran, C. M.; Distefano, S.

    1986-01-01

    The Jet Propulsion Laboratory is investigating the possibility of developing advanced electrochemical techniques as accelerated compatibility tests for metal/propellant systems which overcome the problems associated with the low conductivity of the liquid propellants (e.g., hydrazines, nitrogen tetroxide). Both DC techniques and AC electrochemical impedance spectroscopy are being evaluated. Progress has been made in experiments involving stainless steel with hydrazine and nitrogen tetroxide propellants.

  3. Measuring Combustion Advance in Solid Propellants

    NASA Technical Reports Server (NTRS)

    Yang, L. C.

    1986-01-01

    Set of gauges on solid-propellant rocket motor with electrically insulating case measures advance of combustion front and local erosion rates of propellant and insulation. Data furnished by gauges aid in motor design, failure analysis, and performance prediction. Technique useful in determining propellant uniformity and electrical properties of exhaust plum. Gauges used both in flight and on ground. Foilgauge technique also useful in basic research on pulsed plasmas or combustion of solids.

  4. Motion of microbeads propelled by bacterial chemotaxis in a microfluidic platform

    NASA Astrophysics Data System (ADS)

    Kim, Dong Wook; Kim, Young Won; Yoo, Jung Yul

    2009-11-01

    Micro actuators propelled by bacteria are of great interest in recent years, because bacterial chemotaxis has well-presented one of the very promising solutions to the utilization of the motion of flagellated bacteria. In this work, the motion of fluorescent microbeads driven by bacterial chemotaxis has been analyzed by micro-particle tracking velocimetry (μ-PTV). Flagellated bacteria, Serratia Marcescens, are attached to the surface of the polystyrene (PS) microbeads spontaneously in an aqueous culture solution. Then, these particles are injected in the test medium where the linear concentration gradient of L-aspartate is maintained, which is generated by convective and molecular diffusions in a microfluidic platform. It is observed that the particles slowly move toward the high-concentration zone of L-aspartate. This work shows that migration of microbeads using bacterial chemotaxis can be one of the effective tools for the applications to actuators of micro-bio robots.

  5. Flow-mediated interactions between two self-propelled flapping filaments in tandem configuration.

    PubMed

    Zhu, Xiaojue; He, Guowei; Zhang, Xing

    2014-12-01

    The mechanism by which aggregates of active swimmers are formed is an intriguing problem. In this Letter we show that, for two tandem self-propelled filaments driven by harmonic plunging motions of identical frequency and amplitude, stable configurations can be spontaneously formed by locking the trajectories onto the vortex centers. Further analysis indicates that the grouping energetics is also dictated by the wake vortex structure. The rationale behind the energetic advantage of the follower is found to be the interplay among actuation, self-propulsion, and the vortical fluid environment.

  6. Wet air oxidation of propellant wastewaters

    SciTech Connect

    Randall, T.L.; Copa, W.M.; Deitrich, M.J.

    1985-01-01

    Wet Air Oxidation studies have been conducted on a number of propellant wastewaters, to assess destruction levels of specific propellant components. OTTO fuel, used as a torpedo propellant, and hydrazine based rocket fuels were propellants of interest. OTTO fuel wastewaters contain substantial amounts of propylene glycol dinitrate. Hydrazine based rocket fuel wastewaters contain hydrazine and unsymmetrical dimethyl hydrazine. Laboratory Wet Air Oxidation studies on OTTO fuel wastewaters indicated that a 99+ percent destruction of propylene glycol dinitrate can be achieved at an oxidation temperature of 280/sup 0/C.

  7. Catalytic ignitor for regenerative propellant gun

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E. (Inventor); Ferraro, Ned W. (Inventor)

    1994-01-01

    An ignitor initiates combustion of liquid propellant in a gun by utilizing a heated catalyst onto which the liquid propellant is sprayed in a manner which mitigates the occurrence of undesirable combustion chamber oscillations. The heater heats the catalyst sufficiently to provide the activation necessary to initiate combustion of the liquid propellant sprayed thereonto. Two embodiments of the ignitor and three alternative mountings thereof within the combustion chamber are disclosed. The ignitor may also be utilized to dispose of contaminated, excess, or waste liquid propellant in a safe, controlled, simple, and reliable manner.

  8. Catalytic Ignitor for Regenerative Propellant Gun

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E. (Inventor); Ferraro, Ned W. (Inventor)

    1997-01-01

    An ignitor initiates combustion of liquid propellant in a gun by utilizing a heated catalyst onto which the liquid propellant is sprayed in a manner which mitigates the occurrence of undesirable combustion chamber oscillations. The heater heats the catalyst sufficiently to provide the activation necessary to initiate combustion of the liquid propellant sprayed thereonto. Two embodiments of the igniter and three alternative mountings thereof within the combustion chamber are disclosed. The ignitor may also be utilized to dispose of contaminated, excess, or waste liquid propellant in a safe, controlled, simple, and reliable manner.

  9. The design of propeller blade roots

    NASA Technical Reports Server (NTRS)

    Cordes, G

    1942-01-01

    Predicated on the assumption of certain normal conditions for engine and propeller, simple expressions for the static and dynamic stresses of propeller blade roots are evolved. They, in combination with the fatigue strength diagram of the employed material, afford for each engine power one certain operating point by which the state of stress serving as a basis for the design of the root is defined. Different stress cases must be analyzed, depending on the vibration tendency of engine and use of propeller. The solution affords an insight into the possible introduction of different size classes of propeller.

  10. Low speed propellers: Impact of advanced technologies

    NASA Technical Reports Server (NTRS)

    Keiter, I. D.

    1980-01-01

    Sensitivity studies performed to evaluate the potential of several advanced technological elements on propeller performance, noise, weight, and cost for general aviation aircraft are discussed. Studies indicate that the application of advanced technologies to general aviation propellers can reduce fuel consumption in future aircraft an average of ten percent, meeting current regulatory noise limits. Through the use of composite blade construction, up to 25 percent propeller weight reduction can be achieved. This weight reduction in addition to seven percent propeller efficiency improvements through application of advanced technologies result in four percent reduction in direct operating costs, ten percent reduction in aircraft acquisition cost, and seven percent lower gross weight for general aviation aircraft.

  11. Combustion of Gas-Permeable Gun Propellants

    NASA Astrophysics Data System (ADS)

    Li, Yuxiang; Yang, Weitao; Ying, Sanjiu; Peng, Jinhua

    2015-07-01

    Foamed propellants prepared by supercritical fluid foaming show considerably high burning rates due to their porous structures. To further investigate combustion of foamed propellants, quenched combustion experiments and closed-vessel experiments were carried out, Scanning electron microscopy (SEM) was also used to observe their porous morphology. The SEM images show that foamed propellant grains exhibit a porous core and compact skin. The research results show that the porous core is first burned out and the compact skin is burned out at the later burning stage. The results also demonstrate that pore size exerts an important effect on the burning behaviors of foamed propellants.

  12. Fast-acting valve actuator

    DOEpatents

    Cho, Nakwon

    1980-01-01

    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  13. Electrostatically actuatable light modulating device

    DOEpatents

    Koehler, Dale R.

    1991-01-01

    The electrostatically actuatable light modulator utilizes an opaque substrate plate patterned with an array of aperture cells, the cells comprised of physically positionable dielectric shutters and electrostatic actuators. With incorporation of a light source and a viewing screen, a projection display system is effected. Inclusion of a color filter array aligned with the aperture cells accomplishes a color display. The system is realized in terms of a silicon based manufacturing technology allowing fabrication of a high resolution capability in a physically small device which with the utilization of included magnification optics allows both large and small projection displays.

  14. Electrodynamic actuators for rocket engine valves

    NASA Technical Reports Server (NTRS)

    Fiet, O.; Doshi, D.

    1972-01-01

    Actuators, employed in acoustic loudspeakers, operate liquid rocket engine valves by replacing light paper cones with flexible metal diaphragms. Comparative analysis indicates better response time than solenoid actuators, and improved service life and reliability.

  15. Method and apparatus for actuating vehicle transmission

    SciTech Connect

    Ishida, H.; Ishihara, M.; Uriuhara, M.

    1988-11-15

    This patent describes a method of actuating a vehicle parallel-gear transmission having gears and an internal lever for moving shift blocks connected with shift rods and shift forks for changing gear ratios of the transmission, a hydraulically controlled select actuator operatively connected to the internal lever for moving the internal lever in a select direction, a hydraulically controlled shift actuator operatively connected to the internal lever for moving the internal lever in a shift direction substantially normal to the select direction, a hydraulically controlled clutch actuator for connecting and disconnecting a clutch of the transmission, and a common fluid discharge passage connected to fluid discharge ports of the select and shift actuators and a fluid discharge port of the clutch actuator, the select and shift actuators being alternately actuatable to effect a gear changing operation.

  16. New electrode materials for dielectric elastomer actuators

    NASA Astrophysics Data System (ADS)

    Yuan, Wei; Lam, Tuling; Biggs, James; Hu, Liangbing; Yu, Zhibin; Ha, Soonmok; Xi, Dongjuan; Senesky, Matthew K.; Grüner, George; Pei, Qibing

    2007-04-01

    Dielectric elastomer actuators exert strain due to an applied electric field. With advantageous properties such as high efficiency and their light weight, these actuators are attractive for a variety of applications ranging from biomimetic robots, medical prosthetics to conventional pumps and valves. The performance and reliability however, are limited by dielectric breakdown which occurs primarily from localized defects inherently present in the polymer film during actuation. These defects lead to electric arcing, causing a short circuit that shuts down the entire actuator and can lead to actuator failure at fields significantly lower than the intrinsic strength of the material. This limitation is particularly a problem in actuators using large-area films. Our recent studies have shown that the gap between the strength of the intrinsic material and the strength of large-area actuators can be reduced by electrically isolating defects in the dielectric film. As a result, the performance and reliability of dielectric elastomers actuators can be substantially improved.

  17. Anisotropy of Electroactive Strain in Textured Polypyrrole Actuators

    NASA Astrophysics Data System (ADS)

    Pytel, Rachel; Thomas, Edwin; Hunter, Ian

    2006-03-01

    Polypyrrole has been extensively studied as an electroactive material, but these studies have provided little insight to the influence that morphology has on actuation at the nanoscale. By discovering and exploiting the connection between nanoscale transport events and macroscale active strain, we can learn how to process polypyrrole and other conducting polymers for improved electroactive device performance. We show that by controlling polymer chain configuration and packing, a conducting polymer actuator can be engineered that shows a significantly larger macroscopic electroactive response for a given set of driving conditions. We utilize different modes of deformation to impart orientation textures that can be observed via synchrotron x-ray diffraction and electronic and ionic resistance measurements. Certain textures enhance pathways for ion transport between polymer chains, resulting in an anisotropic electroactive strain response that can be harnessed when making polypyrrole-driven devices. This response provides valuable insight to the mechanism of polypyrrole actuation on the nanoscale, supporting a mechanism where counterions migrate to locations between the oriented polymer chains.

  18. Magnetically actuated liquid crystals.

    PubMed

    Wang, Mingsheng; He, Le; Zorba, Serkan; Yin, Yadong

    2014-07-01

    Ferrimagnetic inorganic nanorods have been used as building blocks to construct liquid crystals with optical properties that can be instantly and reversibly controlled by manipulating the nanorod orientation using considerably weak external magnetic fields (1 mT). Under an alternating magnetic field, they exhibit an optical switching frequency above 100 Hz, which is comparable to the performance of commercial liquid crystals based on electrical switching. By combining magnetic alignment and lithography processes, it is also possible to create patterns of different polarizations in a thin composite film and control over the transmittance of light in particular areas. Developing such magnetically responsive liquid crystals opens the door toward various applications, which may benefit from the instantaneous and contactless nature of magnetic manipulation.

  19. Injection dynamics of gelled propellants

    NASA Astrophysics Data System (ADS)

    Yoon, Changjin

    Gel propellants have been recognized as attractive candidates for future propulsion systems due to the reduced tendency to spill and the energy advantages over solid propellants. One of strong benefits emphasized in gel propellant applications is a throttling capability, but the accurate flow control is more complicated and difficult than with conventional Newtonian propellants because of the unique rheological behaviors of gels. This study is a computational effort directed to enhance understanding of the injector internal flow characteristics for gel propellants under rocket injection conditions. In simulations, the emphasized rheology is a shear-thinning which represents a viscosity decrease with increasing a shear rate. It is described by a generalized Newtonian fluid constitutive equation and Carreau-Yasuda model. Using this rheological model, two injection schemes are considered in the present study: axially-fed and cross-fed injection for single-element and multi-element impinging injectors, respectively. An axisymmetric model is developed to describe the axially-fed injector flows and fully three-dimensional model is utilized to simulate cross-fed injector flows. Under axially-fed injection conditions investigated, three distinct modes, an unsteady, steady, and hydraulic flip mode, are observed and mapped in terms of Reynolds number and orifice design. In an unsteady mode, quasi-periodic oscillations occur near the inlet lip leading mass pulsations and viscosity fluctuations at the orifice exit. This dynamic behavior is characterized using a time-averaged discharge coefficient, oscillation magnitude and frequency by a parametric study with respect to an orifice design, Reynolds number and rheology. As a result, orifice exit flows for gel propellants appear to be significantly influenced by a viscous damping and flow resistance due to a shear thinning behavior and these are observed in each factors considered. Under conditions driven by a manifold crossflow

  20. Reformulation of Stmerin(®) D CFC formulation using HFA propellants.

    PubMed

    Murata, Saburo; Izumi, Takashi; Ito, Hideki

    2013-01-01

    Stmerin(®) D was reformulated using hydrofluoroalkanes (HFA-134a and HFA-227) as alternative propellants instead of chlorofluorocarbons (CFCs), where the active ingredients were suspended in mixed CFCs (CFC-11/CFC-12/CFC-114). Here, we report the suspension stability and spray performance of the original CFC formulation and a reformulation using HFAs. We prepared metered dose inhalers (MDI) using HFAs with different surfactants and co-solvents, and investigated the effect on suspension stability by visual testing. We found that the drug suspension stability was poor in both HFAs, but was improved, particularly for HFA-227, by adding a middle chain fatty acid triglycerides (MCT) to the formulation. However, the vapor pressure of HFA-227 is higher than a CFC mixture and this increased the fine particle dose (FPD). Spray performance was adjusted by altering the actuator configuration, and the performance of different actuators was tested by cascade impaction. We found the spray performance could be controlled by the configuration of the actuator. A spray performance comparable to the original formulation was obtained with a 0.8 mm orifice diameter and a 90° cone angle. These results demonstrate that the reformulation of Stmerin(®) D using HFA-227 is feasible, by using MCT as a suspending agent and modifying the actuator configuration. PMID:22519407

  1. Reformulation of Stmerin(®) D CFC formulation using HFA propellants.

    PubMed

    Murata, Saburo; Izumi, Takashi; Ito, Hideki

    2013-01-01

    Stmerin(®) D was reformulated using hydrofluoroalkanes (HFA-134a and HFA-227) as alternative propellants instead of chlorofluorocarbons (CFCs), where the active ingredients were suspended in mixed CFCs (CFC-11/CFC-12/CFC-114). Here, we report the suspension stability and spray performance of the original CFC formulation and a reformulation using HFAs. We prepared metered dose inhalers (MDI) using HFAs with different surfactants and co-solvents, and investigated the effect on suspension stability by visual testing. We found that the drug suspension stability was poor in both HFAs, but was improved, particularly for HFA-227, by adding a middle chain fatty acid triglycerides (MCT) to the formulation. However, the vapor pressure of HFA-227 is higher than a CFC mixture and this increased the fine particle dose (FPD). Spray performance was adjusted by altering the actuator configuration, and the performance of different actuators was tested by cascade impaction. We found the spray performance could be controlled by the configuration of the actuator. A spray performance comparable to the original formulation was obtained with a 0.8 mm orifice diameter and a 90° cone angle. These results demonstrate that the reformulation of Stmerin(®) D using HFA-227 is feasible, by using MCT as a suspending agent and modifying the actuator configuration.

  2. Distributed structural control using multilayered piezoelectric actuators

    NASA Technical Reports Server (NTRS)

    Cudney, Harley H.; Inman, Daniel J.; Oshman, Yaakov

    1990-01-01

    A method of segmenting piezoelectric sensors and actuators is proposed which can preclude the currently experienced cancelation of sensor signals, or the reduction of actuator effectiveness, due to the integration of the property undergoing measurement or control. The segmentation method is demonstrated by a model developed for beam structures, to which multiple layers of piezoelectric materials are attached. A numerical study is undertaken of increasing active and passive damping of a beam using the segmented sensors and actuators over unsegmented sensors and actuators.

  3. Piezoelectric Actuators On A Cold Finger

    NASA Technical Reports Server (NTRS)

    Kuo, Chin-Po; Garba, John A.; Glaser, Robert J.

    1995-01-01

    Developmental system for active suppression of vibrations of cold finger includes three piezoelectric actuators bonded to outer surface. Actuators used to suppress longitudinal and lateral vibrations of upper end of cold finger by applying opposing vibrations. Cold finger in question is part of a cryogenic system associated with an infrared imaging detector. When fully developed, system would be feedback sensor/control/actuator system automatically adapting to changing vibrational environment and suppresses pressure-induced vibrations by imposing compensatory vibrations via actuators.

  4. Active Flow Separation Control on a NACA 0015 Wing Using Fluidic Actuators

    NASA Technical Reports Server (NTRS)

    Melton, Latunia P.

    2014-01-01

    Results are presented from a recent set of wind tunnel experiments using sweeping jet actuators to control ow separation on the 30% chord trailing edge ap of a 30 deg. swept wing model with an aspect ratio (AR) of 4.35. Two sweeping jet actuator locations were examined, one on the flap shoulder and one on the trailing edge flap. The parameters that were varied included actuator momentum, freestream velocity, and trailing edge flap deflection (Delta f ) angle. The primary focus of this set of experiments was to determine the mass flow and momentum requirements for controlling separation on the flap, especially at large flap deflection angles which would be characteristic of a high lift system. Surface pressure data, force and moment data, and stereoscopic particle image velocimetry (PIV) data were acquired to evaluate the performance benefits due to applying active flow control. Improvements in lift over the majority of the wing span were obtained using sweeping jet actuator control. High momentum coefficient, Cu, levels were needed when using the actuators on the ap because they were located downstream of separation. Actuators on the flap shoulder performed slightly better but actuator size, orientation, and spacing still need to be optimized.

  5. Light metal explosives and propellants

    DOEpatents

    Wood, Lowell L.; Ishikawa, Muriel Y.; Nuckolls, John H.; Pagoria, Phillip F.; Viecelli, James A.

    2005-04-05

    Disclosed herein are light metal explosives, pyrotechnics and propellants (LME&Ps) comprising a light metal component such as Li, B, Be or their hydrides or intermetallic compounds and alloys containing them and an oxidizer component containing a classic explosive, such as CL-20, or a non-explosive oxidizer, such as lithium perchlorate, or combinations thereof. LME&P formulations may have light metal particles and oxidizer particles ranging in size from 0.01 .mu.m to 1000 .mu.m.

  6. Low-g propellant gaging

    NASA Astrophysics Data System (ADS)

    Orton, George

    1987-09-01

    A program to develop and demonstrate technology for low gravity propellant gaging on future geostationary satellites is described. Evaluations were performed to select four gaging concepts for ground tests and low gravity tests in the NASA KC-135 aircraft. The selected concepts were: (1) an ultrasonic point sensor system, (2) a nucleonic gaging system, (3) an ultrasonic torsional wave guide, and (4) an ultrasonic flowmeter. As a result of successful ground and KC-135 tests, two concepts (the ultrasonic point sensor and the nucleonic systems) were selected for orbital test in a shuttle Get-Away-Special experiment.

  7. Constitutive equations for solid propellants

    SciTech Connect

    Oezuepek, S.; Becker, E.B.

    1997-04-01

    Mechanical behavior of the Space Shuttle redesigned solid rocket motor (RSRM) propellant is studied from a phenomenological point of view. Motivated by the study of the experimental data three initially isotropic constitutive models have been developed. All models represent the effect of strain rate, superimposed hydrostatic pressure, and cyclic loading on the stress and dilatation response of the material. A particular emphasis is given to the prediction of volume dilatation. The model resulting in the best representation of the available data is calibrated using only a few tests. The predictions of the model are compared with experiments for several loading conditions not used in the calibration.

  8. Analysis of propellant feedline dynamics

    NASA Technical Reports Server (NTRS)

    Holster, J. L.; Astleford, W. J.; Gerlach, C. R.

    1973-01-01

    An analytical model and corresponding computer program for studying disturbances of liquid propellants in typical engine feedline systems were developed. The model includes the effects of steady turbulent mean flow, the influence of distributed compliances, the effects of local compliances, and various factors causing structural-hydraulic coupling. The computer program was set up such that the amplitude and phase of the terminal pressure/input excitation is calculated over any desired frequency range for an arbitrary assembly of various feedline components. A user's manual is included.

  9. Optimized actuators for ultrathin deformable primary mirrors.

    PubMed

    Laslandes, Marie; Patterson, Keith; Pellegrino, Sergio

    2015-05-20

    A novel design and selection scheme for surface-parallel actuators for ultrathin, lightweight mirrors is presented. The actuation system consists of electrodes printed on a continuous layer of piezoelectric material bonded to an optical-quality substrate. The electrodes provide almost full coverage of the piezoelectric layer, in order to maximize the amount of active material that is available for actuation, and their shape is optimized to maximize the correctability and stroke of the mirror for a chosen number of independent actuators and for a dominant imperfection mode. The starting point for the design of the electrodes is the observation that the correction of a figure error that has at least two planes of mirror symmetry is optimally done with twin actuators that have the same optimized shape but are rotated through a suitable angle. Additional sets of optimized twin actuators are defined by considering the intersection between the twin actuators, and hence an arbitrarily fine actuation pattern can be generated. It is shown that this approach leads to actuator systems with better performance than simple, geometrically based actuators. Several actuator patterns to correct third-order astigmatism aberrations are presented, and an experimental demonstration of a 41-actuator mirror is also presented. PMID:26192533

  10. Carbon nanotube-polymer composite actuators

    DOEpatents

    Gennett, Thomas; Raffaelle, Ryne P.; Landi, Brian J.; Heben, Michael J.

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  11. Smart patch piezoceramic actuator issues

    NASA Technical Reports Server (NTRS)

    Griffin, Steven F.; Denoyer, Keith K.; Yost, Brad

    1993-01-01

    The Phillips Laboratory is undertaking the challenge of finding new and innovative ways to integrate sensing, actuation, and the supporting control and power electronics into a compact self-contained unit to provide vibration suppression for a host structure. This self-contained unit is commonly referred to as a smart patch. The interfaces to the smart patch will be limited to standard spacecraft power and possibly a communications line. The effort to develop a smart patch involves both contractual and inhouse programs which are currently focused on miniaturization of the electronics associated with vibrational control using piezoceramic sensors and actuators. This paper is comprised of two distinct parts. The first part examines issues associated with bonding piezoceramic actuators to a host structure. Experimental data from several specimens with varying flexural stiffness are compared to predictions from two piezoelectric/substructure coupling models, the Blocked Force Model and the Uniform Strain Model with Perfect Bonding. The second part of the paper highlights a demonstration article smart patch created using the insights gained from inhouse efforts at the Phillips Laboratory. This demonstration article has self contained electronics on the same order of size as the actuator powered by a voltage differential of approximately 32 volts. This voltage is provided by four rechargeable 8 volt batteries.

  12. Status of Electrical Actuator Applications

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Taylor, Linda M.; Hansen, Irving G.

    1996-01-01

    An ever increasing number of actuation functions historically performed by hydraulics or pneumatics are being accomplished by electric actuation. If 'end to end' systems are considered, electric actuators (EA's) are potentially lighter and more efficient. In general, system redundancies may be more easily implemented and operationally monitored. Typically, electrical components exhibit longer mean times to failure and projected lifetime costs of EA's are potentially much lower than those of other options. EA's have certain characteristics which must be considered in their application. The actual mechanical loadings must be established, for the more easily controlled EA may be operated much closer to its full capabilities. At higher rates of motion, EA's are operating as constant power devices. Therefore, it may be possible to start a movement that can not be stopped. The incorporation of high power electronics into remote locations introduces new concerns of EMI and thermal control. It is the management of these and other characteristics that forms the engineering design challenges. Work is currently in progress on EA's for aircraft and expendable launch vehicles. These applications span from ten to 40+ horsepower. The systematics and status of these actuators will be reported along with current technical trends in this area.

  13. Multilayer Piezoelectric Stack Actuator Characterization

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  14. SMA actuators for morphing wings

    NASA Astrophysics Data System (ADS)

    Brailovski, V.; Terriault, P.; Georges, T.; Coutu, D.

    An experimental morphing laminar wing was developed to prove the feasibility of aircraft fuel consumption reduction through enhancement of the laminar flow regime over the wing extrados. The morphing wing prototype designed for subsonic cruise flight conditions (Mach 0.2 … 0.3; angle of attack - 1 … +2∘), combines three principal subsystems: (1) flexible extrados, (2) rigid intrados and (3) an actuator group located inside the wing box. The morphing capability of the wing relies on controlled deformation of the wing extrados under the action of shape memory alloys (SMA) actuators. A coupled fluid-structure model of the morphing wing was used to evaluate its mechanical and aerodynamic performances in different flight conditions. A 0.5 m chord and 1 m span prototype of the morphing wing was tested in a subsonic wind tunnel. In this work, SMA actuators for morphing wings were modeled using a coupled thermo-mechanical finite element model and they were windtunnel validated. If the thermo-mechanical model of SMA actuators presented in this work is coupled with the previously developed structureaerodynamic model of the morphing wing, it could serve for the optimization of the entire morphing wing system.

  15. Development of actuation system for artificial cilia with magnetic elastomer

    NASA Astrophysics Data System (ADS)

    Tsumori, Fujio; Saijou, Akinori; Osada, Toshiko; Miura, Hideshi

    2015-06-01

    In this paper, we describe the development of magnetically actuated artificial cilia. Natural cilia are a highly efficient device that produces flow under a small-Reynolds-number state. There are two important characteristics of natural cilia; one is asymmetric movement, which is composed of effective and recovery strokes, and the other is the phase difference of a stroke in each cilium in an array that will produce a metachronal wave. In this paper, we propose an actuation system for artificial cilia composed of a silicone elastomer and multiparticle chains of a magnetic material. The applied magnetic field is controlled by rotation of a permanent magnet. This rotating magnetic field induced an asymmetric movement similar to that of a natural cilium. We also changed the orientation angle of multiparticle chains to control the phase difference of a stroke in each artificial cilium. This technique would help to realize metachronal waves of artificial cilia.

  16. Effects of propellant composition variables on acceleration-induced burning-rate augmentation of solid propellants

    NASA Technical Reports Server (NTRS)

    Northam, G. B.

    1972-01-01

    This work was conducted to define further the effects of propellant composition variables on the acceleration-induced burning rate augmentation of solid propellants. The rate augmentation at a given acceleration was found to be a nonlinear inverse function of the reference burning rate and not controlled by binder or catalyst type at a given reference rate. A nonaluminized propellant and a low rate double-base propellant exhibited strong transient rate augmentation due to surface pitting resulting from the retention of hot particles on the propellant surface.

  17. Piezoelectric multilayer actuator life test.

    PubMed

    Sherrit, Stewart; Bao, Xiaoqi; Jones, Christopher M; Aldrich, Jack B; Blodget, Chad J; Moore, James D; Carson, John W; Goullioud, Renaud

    2011-04-01

    Potential NASA optical missions such as the Space Interferometer Mission require actuators for precision positioning to accuracies of the order of nanometers. Commercially available multilayer piezoelectric stack actuators are being considered for driving these precision mirror positioning mechanisms. These mechanisms have potential mission operational requirements that exceed 5 years for one mission life. To test the feasibility of using these commercial actuators for these applications and to determine their reliability and the redundancy requirements, a life test study was undertaken. The nominal actuator requirements for the most critical actuators on the Space Interferometry Mission (SIM) in terms of number of cycles was estimated from the Modulation Optics Mechanism (MOM) and Pathlength control Optics Mechanism (POM) and these requirements were used to define the study. At a nominal drive frequency of 250 Hz, one mission life is calculated to be 40 billion cycles. In this study, a set of commercial PZT stacks configured in a potential flight actuator configuration (pre-stressed to 18 MPa and bonded in flexures) were tested for up to 100 billion cycles. Each test flexure allowed for two sets of primary and redundant stacks to be mechanically connected in series. The tests were controlled using an automated software control and data acquisition system that set up the test parameters and monitored the waveform of the stack electrical current and voltage. The samples were driven between 0 and 20 V at 2000 Hz to accelerate the life test and mimic the voltage amplitude that is expected to be applied to the stacks during operation. During the life test, 10 primary stacks were driven and 10 redundant stacks, mechanically in series with the driven stacks, were open-circuited. The stroke determined from a strain gauge, the temperature and humidity in the chamber, and the temperature of each individual stack were recorded. Other properties of the stacks, including the

  18. Gait planning for a quadruped robot with one faulty actuator

    NASA Astrophysics Data System (ADS)

    Chen, Xianbao; Gao, Feng; Qi, Chenkun; Tian, Xinghua

    2015-01-01

    Fault tolerance is essential for quadruped robots when they work in remote areas or hazardous environments. Many fault-tolerant gaits planning method proposed in the past decade constrained more degrees of freedom(DOFs) of a robot than necessary. Thus a novel method to realize the fault-tolerant walking is proposed. The mobility of the robot is analyzed first by using the screw theory. The result shows that the translation of the center of body(CoB) can be kept with one faulty actuator if the rotations of the body are controlled. Thus the DOFs of the robot body are divided into two parts: the translation of the CoB and the rotation of the body. The kinematic model of the whole robot is built, the algorithm is developed to actively control the body orientations at the velocity level so that the planned CoB trajectory can be realized in spite of the constraint of the faulty actuator. This gait has a similar generation sequence with the normal gait and can be applied to the robot at any position. Simulations and experiments of the fault-tolerant gait with one faulty actuator are carried out. The CoB errors and the body rotation angles are measured. Comparing to the traditional fault-tolerant gait they can be reduced by at least 50%. A fault-tolerant gait planning algorithm is presented, which not only realizes the walking of a quadruped robot with a faulty actuator, but also efficiently improves the walking performances by taking full advantage of the remaining operational actuators according to the results of the simulations and experiments.

  19. Materials characterization of propellants using ultrasonics

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Jones, David

    1993-01-01

    Propellant characteristics for solid rocket motors were not completely determined for its use as a processing variable in today's production facilities. A major effort to determine propellant characteristics obtainable through ultrasonic measurement techniques was performed in this task. The information obtained was then used to determine the uniformity of manufacturing methods and/or the ability to determine non-uniformity in processes.

  20. Recovery of aluminum from composite propellants

    NASA Technical Reports Server (NTRS)

    Shaw, G. C. (Inventor)

    1980-01-01

    Aluminum was recovered from solid rocket propellant containing a small amount of oxidizer by depolymerizing and dissolving propellant binders (containing functional or hydrolyzable groups in a solution of sodium methoxide) in an alcohol solvent optionally containing an aliphatic or aromatic hydrocarbon co-solvent. The solution was filtered to recover substantially all the aluminum in active form.

  1. 14 CFR 21.129 - Tests: propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tests: propellers. 21.129 Section 21.129... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate Only § 21.129 Tests: propellers. Each... acceptable functional test to determine if it operates properly throughout the normal range of operation....

  2. 14 CFR 21.129 - Tests: propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Tests: propellers. 21.129 Section 21.129... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.129 Tests: propellers. Each person... functional test to determine if it operates properly throughout the normal range of operation....

  3. 14 CFR 21.129 - Tests: propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Tests: propellers. 21.129 Section 21.129... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.129 Tests: propellers. Each person... functional test to determine if it operates properly throughout the normal range of operation....

  4. 21 CFR 189.191 - Chlorofluorocarbon propellants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Chlorofluorocarbon propellants. 189.191 Section 189.191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... or Use as Human Food § 189.191 Chlorofluorocarbon propellants. The use of chlorofluorocarbons...

  5. Preventing Growth Of Barnacles On Propellers

    NASA Technical Reports Server (NTRS)

    Parrish, Kemp L.

    1993-01-01

    Possible to prevent barnacles and other marine life from obtaining firm bonds on propellers and other metal parts by coating parts with NEDOX (or equivalent) cavitation-resistant material. Available in several forms; one that works best is mold-release coating. Also provides improved surface hardness, protection against electrolysis, better resistance to abrasion, and less friction between propellers and water.

  6. Composite Solid Propellant Predictability and Quality Assurance

    NASA Technical Reports Server (NTRS)

    Ramohalli, Kumar

    1989-01-01

    Reports are presented at the meeting at the University of Arizona on the study of predictable and reliable solid rocket motors. The following subject areas were covered: present state and trends in the research of solid propellants; the University of Arizona program in solid propellants, particularly in mixing (experimental and analytical results are presented).

  7. Destruction of propellant magazine, November 1982

    NASA Astrophysics Data System (ADS)

    Tozer, N. H.

    1984-08-01

    Details on the destruction of a propellant magazine are given. The properties of single base propellants are discussed. Although single base propellants have been around for one hundred years, production of this type of propellant in Australia only commenced during World War 2 when appropriate plant and know how were provided under the Lend Lease Scheme. Most of the single base propellants made at Mulwala Explosives Factory have been of the IMR type i.e., single perforated tubular granules with their surface coated with DNT for use in small to medium calibre ammunition. Since production started at Mulwala Explosives Factory in 1944 some fourteen different versions of style of propellant have been manufactured. Four versions only were made up until 1957 and these were identified with an IMR type number matching the US propellants from which they were copied. New varieties introduced since 1957 have been identified with an AR aeries number commencing with AR2001 - the original Australian 7.62 mm rifle propellant.

  8. ISRU Propellant Selection for Space Exploration Vehicles

    NASA Technical Reports Server (NTRS)

    Chen, Timothy T.

    2013-01-01

    Chemical propulsion remains the only viable solution as technically matured technology for the near term human space transportation to Lunar and Mars. Current mode of space travel requires us to "take everything we will need", including propellant for the return trip. Forcing the mission designers to carry propellant for the return trip limits payload mass available for mission operations and results in a large and costly (and often unaffordable) design. Producing propellant via In-Situ Resource Utilization (ISRU) will enable missions with chemical propulsion by the "refueling" of return-trip propellant. It will reduce vehicle propellant mass carrying requirement by over 50%. This mass reduction can translates into increased payload to enhance greater mission capability, reduces vehicle size, weight and cost. It will also reduce size of launch vehicle fairing size as well as number of launches for a given space mission and enables exploration missions with existing chemical propulsion. Mars remains the ultimate destination for Human Space Exploration within the Solar System. The Mars atmospheric consist of 95% carbon dioxide (CO2) and the presence of Ice (water) was detected on Mars surfaces. This presents a basic chemical building block for the ISRU propellant manufacturing. However, the rationale for the right propellant to produce via ISRU appears to be limited to the perception of "what we can produce" as oppose to "what is the right propellant". Methane (CH4) is often quoted as a logical choice for Mars ISRU propellant, however; it is believed that there are better alternatives available that can result in a better space transportation architecture. A system analysis is needed to determine on what is the right propellant choice for the exploration vehicle. This paper examines the propellant selection for production via ISRU method on Mars surfaces. It will examine propellant trades for the exploration vehicle with resulting impact on vehicle performance, size

  9. Microprocessor controlled proof-mass actuator

    NASA Technical Reports Server (NTRS)

    Horner, Garnett C.

    1987-01-01

    The objective of the microprocessor controlled proof-mass actuator is to develop the capability to mount a small programmable device on laboratory models. This capability will allow research in the active control of flexible structures. The approach in developing the actuator will be to mount all components as a single unit. All sensors, electronic and control devices will be mounted with the actuator. The goal for the force output capability of the actuator will be one pound force. The programmable force actuator developed has approximately a one pound force capability over the usable frequency range, which is above 2 Hz.

  10. Fish-skeleton visualization of bending actuators

    NASA Astrophysics Data System (ADS)

    Nakshatharan, Sunjai; Punning, Andres; Assi, Siim; Johanson, Urmas; Aabloo, Alvo

    2016-04-01

    We present a novel experimental method for qualitative visualization and quantitative characterization of the time-dependent behavior of bending ionic electroactive polymer actuators. The thin fibers, attached to the actuator, represent the surface normal at the given points of the bending actuator. The structure, formed by the skeleton of many adjacent fibers, amplifies the visual overview about the whole actuator. The four coordinates formed by four tips of two fibers enable determining the axial as well as the bending strains of a bending actuator.

  11. Fish-like propulsion of an airship with planar membrane dielectric elastomer actuators.

    PubMed

    Jordi, C; Michel, S; Fink, E

    2010-06-01

    The goal of our project is to mimic fish-like movement in air, propelling an airship by undulating its hull and a caudal fin. The activation of the fish-like body in air is realized by dielectric elastomers. These actuators are quite unique for their soft light-weight membrane structure and they are therefore very appropriate to the application on inflated structures. The principles of biomimetics for the structural design and movement are discussed and the conception and design of the airship is described. Various development tests, including wind tunnel testing and flight trials, were performed and the results obtained are presented. It can be shown that an 8 m model airship can be propelled in a fish-like manner in air and that the propulsion can be drastically improved by undulating the body as well as the caudal fin contrary to propulsion with only the caudal fin. PMID:20498517

  12. SRM propellant, friction/ESD testing

    NASA Technical Reports Server (NTRS)

    Campbell, L. A.

    1989-01-01

    Following the Pershing 2 incident in 1985 and the Peacekeeper ignition during core removal in 1987, it was found that propellant can be much more sensitive to Electrostatic Discharges (ESD) than ever before realized. As a result of the Peacekeeper motor near miss incident, a friction machine was designed and fabricated, and used to determine friction hazards during core removal. Friction testing with and electrical charge being applied across the friction plates resulted in propellant ignitions at low friction pressures and extremely low ESD levels. The objective of this test series was to determine the sensitivity of solid rocket propellant to combined friction pressure and electrostatic stimuli and to compare the sensitivity of the SRM propellant to Peacekeeper propellant. The tests are fully discussed, summarized and conclusions drawn.

  13. Handbook on Hypergolic Propellant Discharges and Disposal

    NASA Technical Reports Server (NTRS)

    Bowman, T. E.; Sivik, H. E.; Thomas, J. J.

    1977-01-01

    The efficiency of all treatment methods formerly or currently used in treating chemical wastes is assessed with emphasis on the disposal of hypergolic propellants. Maximum focus is on the space shuttle propellants MMH and N2O4. Except for hydrogen peroxide oxidizers, all the propellants are nitrogen based and can be potentially reduced to valuable plant nutrients. In theory, all the propellants can be reduced to carbon, hydrogen, nitrogen, and oxygen, except of fuming nitric acid which contains a small amount of fluorine. Appendices cover: (1) a general design criteria for disposal ponds; (2) thermal aspects of reaction in dilute solution; (3) gas bubble growth, detachment, and rise (4) absorption scrubber fundamentals and descriptions; (5) separation of a propellant vapor from a helium stream by permeation; and (6) atmospheric emission limits.

  14. Storage of solid propellants in space

    NASA Technical Reports Server (NTRS)

    Udlock, D. E.

    1977-01-01

    A test program is described which determines the extent of physical property changes that result from extended space exposure. Primary emphasis was placed on determining the effects of space vacuum. Solid propellants were stored and their physical properties tested in a vacuum and in a dry environment. The storage caused significantly greater increases in the propellants' modulus and maximum tensile strength than occurred in parallel ambient stored samples. The data indicate that the loss of trace amounts of residual moisture from cured propellant is the apparent cause of the observed propellant property changes. Therefore, initial screening tests were carried out under dry storage conditions. Upon completion of the dry storage tests, appropriate propellant samples are exposed to an actual space environment using the Long Duration Exposure Facility (LDEF).

  15. AP reclamation and reuse in RSRM propellant

    NASA Technical Reports Server (NTRS)

    Miks, Kathryn F.; Harris, Stacey A.

    1995-01-01

    A solid propellant ingredient reclamation pilot plant has been evaluated at the Strategic Operations of Thiokol Corporation, located in Brigham City, Utah. The plant produces AP wet cake (95 percent AP, 5 percent water) for recycling at AP vendors. AP has been obtained from two standard propellant binder systems (PBAN and HTPB). Analytical work conducted at Thiokol indicates that the vendor-recrystallized AP meets Space Shuttle propellant specification requirements. Thiokol has processed 1-, 5-, and 600-gallon propellant mixes with the recrystallized AP. Processing, cast, cure, ballistic, mechanical, and safety properties have been evaluated. Phillips Laboratory static-test-fired 70-pound and 800-pound BATES motors. The data indicate that propellant processed with reclaimed AP has nominal properties.

  16. Thrust engine and propellant exhaust arrangement therefor

    SciTech Connect

    Retallick, F.D.

    1981-01-27

    A nuclear engine and nozzle arrangement are described for a nuclear rocket comprising a cluster of elongated fissile fuel bearing and high temperature capacity modules suitably supported in a pressure vessel. The modules have a plurality of coolant-propellant channels extending therethrough, a convergent - divergent nozzle structure of fixed cross-sectional dimensions secured to the end portion of each of said modules, a divergent-only unitary skirt member connected directly to the propellant exit end of said modular cluster in series with and diverging from the divergent ends of said convergent-divergent nozzle structures. The modules are formed to conduct a compressible propellant therethrough at sub-sonic velocities, said nozzle structures being formed to develop supersonic velocities of the propellant and said divergent-only skirt being formed to develop further the supersonic velocities of said propellant.

  17. Annoyance caused by propeller airplane flyover noise

    NASA Technical Reports Server (NTRS)

    Mccurdy, D. A.; Powell, C. A.

    1984-01-01

    Laboratory experiments were conducted to provide information on quantifying the annoyance response of people to propeller airplane noise. The items of interest were current noise metrics, tone corrections, duration corrections, critical band corrections, and the effects of engine type, operation type, maximum takeoff weight, blade passage frequency, and blade tip speed. In each experiment, 64 subjects judged the annoyance of recordings of propeller and jet airplane operations presented at d-weighted sound pressure levels of 70, 80, and 90 dB in a testing room which simulates the outdoor acoustic environment. The first experiment examined 11 propeller airplanes with maximum takeoff weights greater than or equal to 5700 kg. The second experiment examined 14 propeller airplanes weighting 5700 kg or less. Five jet airplanes were included in each experiment. For both the heavy and light propeller airplanes, perceived noise level and perceived level (Stevens Mark VII procedure) predicted annoyance better than other current noise metrics.

  18. The theory of the screw propeller

    NASA Technical Reports Server (NTRS)

    Betz, A

    1922-01-01

    Given here is a brief review of the fundamental principles of the propeller slip-stream theory and its further development through later researches, which demonstrate the connection between the propeller slip-stream theory and Frounde's so-called 'propeller blade theory.' The propeller slip-stream theory, especially in its improved form, now gives us the basis for determining the mutual influence of the parts of the blade, so that, in calculating the shape of the blade, we can get along with certain section characteristics, which have been determined once and for all. It is argued that new theories present the possibility of investigating the phenomena in the vicinity of the propeller, allowing us to calculate its action on the basis of fewer experimental values.

  19. MAST Propellant and Delivery System Design Methods

    NASA Technical Reports Server (NTRS)

    Nadeem, Uzair; Mc Cleskey, Carey M.

    2015-01-01

    A Mars Aerospace Taxi (MAST) concept and propellant storage and delivery case study is undergoing investigation by NASA's Element Design and Architectural Impact (EDAI) design and analysis forum. The MAST lander concept envisions landing with its ascent propellant storage tanks empty and supplying these reusable Mars landers with propellant that is generated and transferred while on the Mars surface. The report provides an overview of the data derived from modeling between different methods of propellant line routing (or "lining") and differentiate the resulting design and operations complexity of fluid and gaseous paths based on a given set of fluid sources and destinations. The EDAI team desires a rough-order-magnitude algorithm for estimating the lining characteristics (i.e., the plumbing mass and complexity) associated different numbers of vehicle propellant sources and destinations. This paper explored the feasibility of preparing a mathematically sound algorithm for this purpose, and offers a method for the EDAI team to implement.

  20. Dielectric elastomer actuators for facial expression

    NASA Astrophysics Data System (ADS)

    Wang, Yuzhe; Zhu, Jian

    2016-04-01

    Dielectric elastomer actuators have the advantage of mimicking the salient feature of life: movements in response to stimuli. In this paper we explore application of dielectric elastomer actuators to artificial muscles. These artificial muscles can mimic natural masseter to control jaw movements, which are key components in facial expressions especially during talking and singing activities. This paper investigates optimal design of the dielectric elastomer actuator. It is found that the actuator with embedded plastic fibers can avert electromechanical instability and can greatly improve its actuation. Two actuators are then installed in a robotic skull to drive jaw movements, mimicking the masseters in a human jaw. Experiments show that the maximum vertical displacement of the robotic jaw, driven by artificial muscles, is comparable to that of the natural human jaw during speech activities. Theoretical simulations are conducted to analyze the performance of the actuator, which is quantitatively consistent with the experimental observations.

  1. How does the presence of a body affect the performance of an actuator disk ?

    NASA Astrophysics Data System (ADS)

    de Oliveira, G.; Pereira, R. B.; Ragni, D.; Avallone, F.; van Bussel, G.

    2016-09-01

    The article seeks to unify the treatment of conservative force interactions between axi-symmetric bodies and actuators in inviscid flow. Applications include the study of hub interference, diffuser augmented wind turbines and boundary layer ingestion propeller configurations. The conservation equations are integrated over infinitesimal streamtubes to obtain an exact momentum model contemplating the interaction between an actuator and a nearby body. No assumptions on the shape or topology of the body are made besides (axi)symmetry. Laws are derived for the thrust coefficient, power coefficient and propulsive efficiency. The proposed methodology is articulated with previous efforts and validated against the numerical predictions of a planar vorticity equation solver. Very good agreement is obtained between the analytical and numerical methods.

  2. Light-Driven Polymeric Bimorph Actuators

    NASA Technical Reports Server (NTRS)

    Adamovsky, Gregory; Sarkisov, Sergey S.; Curley, Michael J.

    2009-01-01

    Light-driven polymeric bimorph actuators are being developed as alternatives to prior electrically and optically driven actuators in advanced, highly miniaturized devices and systems exemplified by microelectromechanical systems (MEMS), micro-electro-optical-mechanical systems (MEOMS), and sensor and actuator arrays in smart structures. These light-driven polymeric bimorph actuators are intended to satisfy a need for actuators that (1) in comparison with the prior actuators, are simpler and less power-hungry; (2) can be driven by low-power visible or mid-infrared light delivered through conventional optic fibers; and (3) are suitable for integration with optical sensors and multiple actuators of the same or different type. The immediate predecessors of the present light-driven polymeric bimorph actuators are bimorph actuators that exploit a photorestrictive effect in lead lanthanum zirconate titanate (PLZT) ceramics. The disadvantages of the PLZT-based actuators are that (1) it is difficult to shape the PLZT ceramics, which are hard and brittle; (2) for actuation, it is necessary to use ultraviolet light (wavelengths < 380 nm), which must be generated by use of high-power, high-pressure arc lamps or lasers; (3) it is difficult to deliver sufficient ultraviolet light through conventional optical fibers because of significant losses in the fibers; (4) the response times of the PLZT actuators are of the order of several seconds unacceptably long for typical applications; and (5) the maximum mechanical displacements of the PLZT-based actuators are limited to those characterized by low strains beyond which PLZT ceramics disintegrate because of their brittleness. The basic element of a light-driven bimorph actuator of the present developmental type is a cantilever beam comprising two layers, at least one of which is a polymer that exhibits a photomechanical effect (see figure). The dominant mechanism of the photomechanical effect is a photothermal one: absorption of

  3. 2-D steering and propelling of acoustic bubble-powered microswimmers.

    PubMed

    Feng, Jian; Yuan, Junqi; Cho, Sung Kwon

    2016-06-21

    This paper describes bi-directional (linear and rotational) propelling and 2-D steering of acoustic bubble-powered microswimmers that are achieved in a centimeter-scale pool (beyond chip level scale). The core structure of a microswimmer is a microtube with one end open in which a gaseous bubble is trapped. The swimmer is propelled by microstreaming flows that are generated when the trapped bubble is oscillated by an external acoustic wave. The bubble oscillation and thus propelling force are highly dependent on the frequency of the acoustic wave and the bubble length. This dependence is experimentally studied by measuring the resonance behaviors of the testing pool and bubble using a laser Doppler vibrometer (LDV) and by evaluating the generated streaming flows. The key idea in the present 2-D steering is to utilize this dependence. Multiple bubbles with different lengths are mounted on a single microswimmer with a variety of arrangements. By controlling the frequency of the acoustic wave, only frequency-matched bubbles can strongly oscillate and generate strong propulsion. By arranging multiple bubbles of different lengths in parallel but with their openings opposite and switching the frequency of the acoustic wave, bi-directionally linear propelling motions are successfully achieved. The propelling forces are calculated by a CFD analysis using the Ansys Fluent® package. For bi-directional rotations, a similar method but with diagonal arrangement of bubbles on a rectangular swimmer is also applied. The rotation can be easily reversed when the frequency of the acoustic wave is switched. For 2-D steering, short bubbles are aligned perpendicular to long bubbles. It is successfully demonstrated that the microswimmer navigates through a T-junction channel under full control with and without carrying a payload. During the navigation, the frequency is the main control input to select and resonate targeted bubbles. All of these operations are achieved by a single

  4. 2-D steering and propelling of acoustic bubble-powered microswimmers.

    PubMed

    Feng, Jian; Yuan, Junqi; Cho, Sung Kwon

    2016-06-21

    This paper describes bi-directional (linear and rotational) propelling and 2-D steering of acoustic bubble-powered microswimmers that are achieved in a centimeter-scale pool (beyond chip level scale). The core structure of a microswimmer is a microtube with one end open in which a gaseous bubble is trapped. The swimmer is propelled by microstreaming flows that are generated when the trapped bubble is oscillated by an external acoustic wave. The bubble oscillation and thus propelling force are highly dependent on the frequency of the acoustic wave and the bubble length. This dependence is experimentally studied by measuring the resonance behaviors of the testing pool and bubble using a laser Doppler vibrometer (LDV) and by evaluating the generated streaming flows. The key idea in the present 2-D steering is to utilize this dependence. Multiple bubbles with different lengths are mounted on a single microswimmer with a variety of arrangements. By controlling the frequency of the acoustic wave, only frequency-matched bubbles can strongly oscillate and generate strong propulsion. By arranging multiple bubbles of different lengths in parallel but with their openings opposite and switching the frequency of the acoustic wave, bi-directionally linear propelling motions are successfully achieved. The propelling forces are calculated by a CFD analysis using the Ansys Fluent® package. For bi-directional rotations, a similar method but with diagonal arrangement of bubbles on a rectangular swimmer is also applied. The rotation can be easily reversed when the frequency of the acoustic wave is switched. For 2-D steering, short bubbles are aligned perpendicular to long bubbles. It is successfully demonstrated that the microswimmer navigates through a T-junction channel under full control with and without carrying a payload. During the navigation, the frequency is the main control input to select and resonate targeted bubbles. All of these operations are achieved by a single

  5. Runtime and Pressurization Analyses of Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Field, Robert E.; Ryan, Harry M.; Ahuja, Vineet; Hosangadi, Ashvin; Lee, Chung P.

    2007-01-01

    Multi-element unstructured CFD has been utilized at NASA SSC to carry out analyses of propellant tank systems in different modes of operation. The three regimes of interest at SSC include (a) tank chill down (b) tank pressurization and (c) runtime propellant draw-down and purge. While tank chill down is an important event that is best addressed with long time-scale heat transfer calculations, CFD can play a critical role in the tank pressurization and runtime modes of operation. In these situations, problems with contamination of the propellant by inclusion of the pressurant gas from the ullage causes a deterioration of the quality of the propellant delivered to the test article. CFD can be used to help quantify the mixing and propellant degradation. During tank pressurization under some circumstances, rapid mixing of relatively warm pressurant gas with cryogenic propellant can lead to rapid densification of the gas and loss of pressure in the tank. This phenomenon can cause serious problems during testing because of the resulting decrease in propellant flow rate. With proper physical models implemented, CFD can model the coupling between the propellant and pressurant including heat transfer and phase change effects and accurately capture the complex physics in the evolving flowfields. This holds the promise of allowing the specification of operational conditions and procedures that could minimize the undesirable mixing and heat transfer inherent in propellant tank operation. It should be noted that traditional CFD modeling is inadequate for such simulations because the fluids in the tank are in a range of different sub-critical and supercritical states and elaborate phase change and mixing rules have to be developed to accurately model the interaction between the ullage gas and the propellant. We show a typical run-time simulation of a spherical propellant tank, containing RP-1 in this case, being pressurized with room-temperature nitrogen at 540 R. Nitrogen

  6. Efficient Hybrid Actuation Using Solid-State Actuators

    NASA Technical Reports Server (NTRS)

    Leo, Donald J.; Cudney, Harley H.; Horner, Garnett (Technical Monitor)

    2001-01-01

    Piezohydraulic actuation is the use of fluid to rectify the motion of a piezoelectric actuator for the purpose of overcoming the small stroke limitations of the material. In this work we study a closed piezohydraulic circuit that utilizes active valves to rectify the motion of a hydraulic end affector. A linear, lumped parameter model of the system is developed and correlated with experiments. Results demonstrate that the model accurately predicts the filtering of the piezoelectric motion caused by hydraulic compliance. Accurate results are also obtained for predicting the unidirectional motion of the cylinder when the active valves are phased with respect to the piezoelectric actuator. A time delay associated with the mechanical response of the valves is incorporated into the model to reflect the finite time required to open or close the valves. This time delay is found to be the primary limiting factor in achieving higher speed and greater power from the piezohydraulic unit. Experiments on the piezohydraulic unit demonstrate that blocked forces on the order of 100 N and unloaded velocities of 180 micrometers/sec are achieved.

  7. Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator.

    PubMed

    Kim, Sung Hoon; Shin, Kyoosik; Hashi, Shuichiro; Ishiyama, Kazushi

    2012-09-01

    This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities. PMID:22550128

  8. Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator.

    PubMed

    Kim, Sung Hoon; Shin, Kyoosik; Hashi, Shuichiro; Ishiyama, Kazushi

    2012-09-01

    This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities.

  9. Characterization, fabrication, and analysis of soft dielectric elastomer actuators capable of complex 3D deformation

    NASA Astrophysics Data System (ADS)

    Lai, William

    framework would aid in designing and optimizing the dielectric elastomer actuator configurations for 3D prescribed deformation configuration. Finally, inspired by the membrane textures of bat wings, a study of utilizing fiber reinforcement on dielectric elastomer actuators were conducted for the mechanical and the coupled electromechanical characteristics. Woven fibers were employed on the surface of actuator membrane with different pre-deformed configurations. Experimentally, actuator stiffness changes were measured for up to four orders of magnitude. The orientation of embedded fibers controlled the level and the triggered phase of stiffness changes. A trade-off between the actuator stiffness and stroke could be controlled during the fabrication stage by the fiber orientation and the prestretch level of the base elastomer membrane. A simplified model using small-strain composite laminate theory was developed and accurately predicted the composite actuator stiffness. Additionally, compliant edge stiffeners were found had to present a marked overall effect on actuator electromechanical response. The developed simplified analytical solutions using Timoshenko-bimaterial laminate solution and composite laminate theory, as well as the developed finite element framework can be utilized in addressing more complex 3D deformation patterns and their electromechanical response.

  10. High performance storable propellant resistojet

    NASA Astrophysics Data System (ADS)

    Vaughan, C. E.

    1992-01-01

    From 1965 until 1985 resistojets were used for a limited number of space missions. Capability increased in stages from an initial application using a 90 W gN2 thruster operating at 123 sec specific impulse (Isp) to a 830 W N2H4 thruster operating at 305 sec Isp. Prior to 1985 fewer than 100 resistojets were known to have been deployed on spacecraft. Building on this base NASA embarked upon the High Performance Storable Propellant Resistojet (HPSPR) program to significantly advance the resistojet state-of-the-art. Higher performance thrusters promised to increase the market demand for resistojets and enable space missions requiring higher performance. During the program three resistojets were fabricated and tested. High temperature wire and coupon materials tests were completed. A life test was conducted on an advanced gas generator.

  11. Physiological response to aerosol propellants.

    PubMed Central

    Stewart, R D; Newton, P E; Baretta, E D; Herrmann, A A; Forster, H V; Soto, R J

    1978-01-01

    Acute exposures to isobutane, propane, F-12, and F-11 in concentrations of 250, 500, or 1000 ppm for periods of 1 min to 8 hr did not produce any untoward physiological effects as determined by the methods employed which included serial EKG's and continuous monitoring of modified V5 by telemetry during exposure. Repetitive exposures to these four propellants were also without measurable untoward physiological effect with the exception of the eight male subjects repetitively exposed to 1000 ppm, F-11, who did show minor decrements in several of the cognitive tests. Of particular importance is the observation that none of the subjects showed any decrement in pulmonary function or alteration in cardiac rhythm as the result of exposure to concentrations of the gases or vapors far greater than encountered in the normal use of aerosol products in the home. PMID:214300

  12. New delivery systems and propellants.

    PubMed

    Dolovich, M

    1999-01-01

    The removal of chlorofluorocarbon (CFC) propellants from industrial and household products has been agreed to by over 165 countries of which more than 135 are developing countries. The timetable for this process is outlined in the Montreal Protocol on Substances that Deplete the Ozone Layer document and in several subsequent amendments. Pressured metered dose inhalers (pMDIs) for medical use have been granted temporary exemptions until replacement formulations, providing the same medication via the same route, and with the same efficacy and safety profiles, are approved for human use. Hydrofluoroalkanes (HFAs) are the alternative propellants for CFCs-12 and -114. Their potential for damage to the ozone layer is nonexistent, and while they are greenhouse gases, their global warming potential is a fraction (one-tenth) of that of CFCs. Replacement formulations for almost all inhalant respiratory medications have been or are being produced and tested; in Canada, it is anticipated that the transition to these HFA or CFC-free pMDIs will be complete by the year 2005. Initially, an HFA pMDI was to be equivalent to the CFC pMDI being replaced, in terms of aerosol properties and effective clinical dose. However, this will not necessarily be the situation, particularly for some corticosteroid products. Currently, only one CFC-free formulation is available in Canada - Airomir, a HFA salbutamol pMDI. This paper discusses the in vitro aerosol characteristics, in vivo deposition and clinical data for several HFA pMDIs for which there are data available in the literature. Alternative delivery systems to the pMDI, namely, dry powder inhalers and nebulizers, are briefly reviewed.

  13. Propellant Chemistry for CFD Applications

    NASA Technical Reports Server (NTRS)

    Farmer, R. C.; Anderson, P. G.; Cheng, Gary C.

    1996-01-01

    Current concepts for reusable launch vehicle design have created renewed interest in the use of RP-1 fuels for high pressure and tri-propellant propulsion systems. Such designs require the use of an analytical technology that accurately accounts for the effects of real fluid properties, combustion of large hydrocarbon fuel modules, and the possibility of soot formation. These effects are inadequately treated in current computational fluid dynamic (CFD) codes used for propulsion system analyses. The objective of this investigation is to provide an accurate analytical description of hydrocarbon combustion thermodynamics and kinetics that is sufficiently computationally efficient to be a practical design tool when used with CFD codes such as the FDNS code. A rigorous description of real fluid properties for RP-1 and its combustion products will be derived from the literature and from experiments conducted in this investigation. Upon the establishment of such a description, the fluid description will be simplified by using the minimum of empiricism necessary to maintain accurate combustion analyses and including such empirical models into an appropriate CFD code. An additional benefit of this approach is that the real fluid properties analysis simplifies the introduction of the effects of droplet sprays into the combustion model. Typical species compositions of RP-1 have been identified, surrogate fuels have been established for analyses, and combustion and sooting reaction kinetics models have been developed. Methods for predicting the necessary real fluid properties have been developed and essential experiments have been designed. Verification studies are in progress, and preliminary results from these studies will be presented. The approach has been determined to be feasible, and upon its completion the required methodology for accurate performance and heat transfer CFD analyses for high pressure, tri-propellant propulsion systems will be available.

  14. Piezoelectric step-motion actuator

    DOEpatents

    Mentesana; Charles P.

    2006-10-10

    A step-motion actuator using piezoelectric material to launch a flight mass which, in turn, actuates a drive pawl to progressively engage and drive a toothed wheel or rod to accomplish stepped motion. Thus, the piezoelectric material converts electrical energy into kinetic energy of the mass, and the drive pawl and toothed wheel or rod convert the kinetic energy of the mass into the desired rotary or linear stepped motion. A compression frame may be secured about the piezoelectric element and adapted to pre-compress the piezoelectric material so as to reduce tensile loads thereon. A return spring may be used to return the mass to its resting position against the compression frame or piezoelectric material following launch. Alternative embodiment are possible, including an alternative first embodiment wherein two masses are launched in substantially different directions, and an alternative second embodiment wherein the mass is eliminated in favor of the piezoelectric material launching itself.

  15. Impact micro-positioning actuator

    NASA Technical Reports Server (NTRS)

    Cuerden, Brian (Inventor); Angel, J. Roger P. (Inventor); Burge, James H. (Inventor); DeRigne, Scott T. (Inventor)

    2006-01-01

    An impact micro-positioning actuator. In one aspect of the invention, a threaded shaft is threadably received in a nut and the nut is impacted by an impacting device, causing the nut first to rotate relative to the shaft by slipping as a result of shaft inertia and subsequently to stick to the shaft as a result of the frictional force therebetween. The nut is returned to its initial position by a return force provided by a return mechanism after impact. The micro-positioning actuator is further improved by controlling at least one and preferably all of the following: the friction, the impact provided by the impacting device, the return force provided by the return mechanism, and the inertia of the shaft. In another aspect of the invention, a threaded shaft is threadably received in a nut and the shaft is impacted by an impacting device, causing the shaft to rotate relative to the nut.

  16. Hydraulically amplified PZT mems actuator

    DOEpatents

    Miles, Robin R.

    2004-11-02

    A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

  17. Launch vehicle performance using metallized propellants

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.; Powell, Richard

    1991-01-01

    Metallized propellant propulsion systems are considered as replacements for the solid rocket boosters and liquid sustainer stages on the current launch vehicles: both the Space Transportation System (STS) and the Titan 4. Liquid rocket boosters for the STS were analyzed as replacements for current solid rocket boosters. These boosters can provide a liquid propulsion system within the volume constraints of a solid rocket booster. A replacement for the Space Shuttle Main Engines using metallized O2/H2/Al was studied. The liquid stages of the Titan 4 were also investigated; the Aerozine-50 (A-50) fuel was replaced with metallized storable A-50/Al. A metallized propellant is similar to a traditional liquid propellant. However, it has metal particles, such as aluminum, that are suspended in a gelled fuel, such as hydrogen, RP-1, A-50 or monomethyl hydrazine (MMH). The fuels then undergo combustion with liquid oxygen or nitrogen tetroxide (NTO). These propellants provide options for increasing the performance of existing launch vehicle chemical propulsion systems by increasing fuel density or specific impulse or both. These increases in density and specific impulse can significantly reduce the propulsion system liftoff weight and allow a liquid rocket booster to fit into the same volume as an existing solid rocket booster. Also, because gelled fuels are akin to liquid propellants, metallized systems can provide enhanced controllability over solid propulsion systems. Gelling of the propellant also reduces the sensitivity to impacts and consequently reduces the propellant explosion hazard.

  18. Launch vehicle performance using metallized propellants

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan; Powell, Richard

    1991-01-01

    Metallized propellant propulsion systems are considered as replacements for the solid rocket boosters and liquid sustainer stages on the current launch vehicles: both the Space Transportation System (STS) and the Titan 4. Liquid rocket boosters for the STS were analyzed as replacements for current solid rocket boosters. These boosters can provide a liquid propulsion system within the volume constraints of a solid rocket booster. A replacement for the Space Shuttle Main Engines using metallized 02/H2/A1 was studied. The liquid stages of the Titan 4 were also investigated; the Aerozine-50 (A-50) fuel was replaced with metallized storable A-50/A1. A metallized propellant is similar to a traditional liquid propellant. However, it has metal particles, such as aluminum, that are suspended in a gelled fuel, such as hydrogen, RP-1, A-50 or monomethyl hydrazine (MMH). The fuels then undergo combustion with liquid oxygen or nitrogen tetroxide (NTO). These propellants provide options for increasing the performance of existing launch vehicle chemical propulsion systems by increasing fuel density or specific impulse or both. These increases in density and specific impulse can significantly reduce the propulsion system liftoff weight and allow a liquid rocket booster to fit into the same volume as an existing solid rocket booster. Also, because gelled fuels are akin to liquid propellants, metallized systems can provide enhanced controllability over solid propulsion systems. Gelling of the propellant also reduces the sensitivity to impacts and consequently reduces the propellant explosion hazard.

  19. Cryogenic Propellant Management Device: Conceptual Design Study

    NASA Technical Reports Server (NTRS)

    Wollen, Mark; Merino, Fred; Schuster, John; Newton, Christopher

    2010-01-01

    Concepts of Propellant Management Devices (PMDs) were designed for lunar descent stage reaction control system (RCS) and lunar ascent stage (main and RCS propulsion) missions using liquid oxygen (LO2) and liquid methane (LCH4). Study ground rules set a maximum of 19 days from launch to lunar touchdown, and an additional 210 days on the lunar surface before liftoff. Two PMDs were conceptually designed for each of the descent stage RCS propellant tanks, and two designs for each of the ascent stage main propellant tanks. One of the two PMD types is a traditional partial four-screen channel device. The other type is a novel, expanding volume device which uses a stretched, flexing screen. It was found that several unique design features simplified the PMD designs. These features are (1) high propellant tank operating pressures, (2) aluminum tanks for propellant storage, and (3) stringent insulation requirements. Consequently, it was possible to treat LO2 and LCH4 as if they were equivalent to Earth-storable propellants because they would remain substantially subcooled during the lunar mission. In fact, prelaunch procedures are simplified with cryogens, because any trapped vapor will condense once the propellant tanks are pressurized in space.

  20. 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.

  1. Actuator device for artificial leg

    NASA Technical Reports Server (NTRS)

    Burch, J. L. (Inventor)

    1976-01-01

    An actuator device is described for moving an artificial leg of a person having a prosthesis replacing an entire leg and hip joint. The device includes a first articulated hip joint assembly carried by the natural leg and a second articulated hip joint assembly carried by the prosthesis whereby energy from the movement of the natural leg is transferred by a compressible fluid from the first hip joint assembly to the second hip joint assembly for moving the artificial leg.

  2. The MJS-77 magnetometer actuator

    NASA Technical Reports Server (NTRS)

    Stange, W. C.

    1977-01-01

    A two-position (0 deg and 180 deg) actuating mechanism (flipper) driven by alternately-heated wax motors (pellets) used to rotate the low field triaxial fluxgate magnetometer experiment on the 1977 Mariner Jupiter-Saturn spacecraft to its 0 deg and 180 deg positions is described. The magnetic field, power requirements, weight and volume of this device are discussed. The problems encountered in design and development of this mechanism are presented.

  3. The MJS-77 magnetometer actuator

    NASA Technical Reports Server (NTRS)

    Stange, W. C.

    1977-01-01

    A two-position (0 deg and 180 deg) actuating mechanism (flipper) driven by alternately-heated wax motors (pellets) will be used to rotate the low field triaxial fluxgate magnetometer experiment on the 1977 Mariner Jupiter-Saturn spacecraft to its 0 deg and 180 deg positions. The magnetic field, power requirements, weight and volume of this device are very restrictive. The problems encountered in design and development of this mechanism are presented.

  4. Analytic Modeling of Pressurization and Cryogenic Propellant

    NASA Technical Reports Server (NTRS)

    Corpening, Jeremy H.

    2010-01-01

    An analytic model for pressurization and cryogenic propellant conditions during all mission phases of any liquid rocket based vehicle has been developed and validated. The model assumes the propellant tanks to be divided into five nodes and also implements an empirical correlation for liquid stratification if desired. The five nodes include a tank wall node exposed to ullage gas, an ullage gas node, a saturated propellant vapor node at the liquid-vapor interface, a liquid node, and a tank wall node exposed to liquid. The conservation equations of mass and energy are then applied across all the node boundaries and, with the use of perfect gas assumptions, explicit solutions for ullage and liquid conditions are derived. All fluid properties are updated real time using NIST Refprop.1 Further, mass transfer at the liquid-vapor interface is included in the form of evaporation, bulk boiling of liquid propellant, and condensation given the appropriate conditions for each. Model validation has proven highly successful against previous analytic models and various Saturn era test data and reasonably successful against more recent LH2 tank self pressurization ground test data. Finally, this model has been applied to numerous design iterations for the Altair Lunar Lander, Ares V Core Stage, and Ares V Earth Departure Stage in order to characterize Helium and autogenous pressurant requirements, propellant lost to evaporation and thermodynamic venting to maintain propellant conditions, and non-uniform tank draining in configurations utilizing multiple LH2 or LO2 propellant tanks. In conclusion, this model provides an accurate and efficient means of analyzing multiple design configurations for any cryogenic propellant tank in launch, low-acceleration coast, or in-space maneuvering and supplies the user with pressurization requirements, unusable propellants from evaporation and liquid stratification, and general ullage gas, liquid, and tank wall conditions as functions of time.

  5. Subsea valve actuator for ultra deepwater

    SciTech Connect

    Ali, S.Z.; Skeels, H.B.; Montemayor, B.K.; Williams, M.R.

    1996-12-31

    This paper reviews the continuing development of gate valve and actuator technology for subsea completions extending into ultra deep water. The basic technical challenges inherent to subsea valve actuators are reviewed, along with the various factors which affect the design and performance of these devices in deepwater applications. The high external ambient pressures which occur in deep water, coupled with high specific gravity hydraulic control fluids, are shown to have a significant impact on the performance of the actuators. This paper presents design and analysis methods and the verification test procedures which are required to develop and qualify new deep water actuator designs. Gate valve actuators of the type described in this paper are currently in use on subsea christmas trees on the world`s deepest subsea wells offshore Brazil (water depths >3,000 feet). New applications of the deepwater actuators are in process for upcoming Gulf of Mexico subsea production systems in water depths approaching 6,000 feet. The actuator/valve development method described in this paper has been confirmed by performance verification testing of full scale valves and actuators using a hyperbaric chamber to simulate ultra deepwater operating conditions. Performance of the test valves and actuators correlated very well with analytical predictions. Test results have confirmed that the new valve actuator designs will satisfy API 17D performance requirements for water depths up to 7,500 feet, well in excess of the upcoming GOM application.

  6. Actuators for a space manipulator

    NASA Technical Reports Server (NTRS)

    Chun, W.; Brunson, P.

    1987-01-01

    The robotic manipulator can be decomposed into distinct subsytems. One particular area of interest of mechanical subsystems is electromechanical actuators (or drives). A drive is defined as a motor with an appropriate transmission. An overview is given of existing, as well as state-of-the-art drive systems. The scope is limited to space applications. A design philosophy and adequate requirements are the initial steps in designing a space-qualified actuator. The focus is on the d-c motor in conjunction with several types of transmissions (harmonic, tendon, traction, and gear systems). The various transmissions will be evaluated and key performance parameters will be addressed in detail. Included in the assessment is a shuttle RMS joint and a MSFC drive of the Prototype Manipulator Arm. Compound joints are also investigated. Space imposes a set of requirements for designing a high-performance drive assembly. Its inaccessibility and cryogenic conditions warrant special considerations. Some guidelines concerning these conditions are present. The goal is to gain a better understanding in designing a space actuator.

  7. Design of high performance piezo composites actuators

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim A.

    Design of high performance piezo composites actuators are developed. Functionally Graded Microstructure (FGM) piezoelectric actuators are designed to reduce the stress concentration at the middle interface existed in the standard bimorph actuators while maintaining high actuation performance. The FGM piezoelectric laminates are composite materials with electroelastic properties varied through the laminate thickness. The elastic behavior of piezo-laminates actuators is developed using a 2D-elasticity model and a modified classical lamination theory (CLT). The stresses and out-of-plane displacements are obtained for standard and FGM piezoelectric bimorph plates under cylindrical bending generated by an electric field throughout the thickness of the laminate. The analytical model is developed for two different actuator geometries, a rectangular plate actuator and a disk shape actuator. The limitations of CLT are investigated against the 2D-elasticity model for the rectangular plate geometry. The analytical models based on CLT (rectangular and circular) and 2D-elasticity are compared with a model based on Finite Element Method (FEM). The experimental study consists of two FGM actuator systems, the PZT/PZT FGM system and the porous FGM system. The electroelastic properties of each layer in the FGM systems were measured and input in the analytical models to predict the FGM actuator performance. The performance of the FGM actuator is optimized by manipulating the thickness of each layer in the FGM system. The thickness of each layer in the FGM system is made to vary in a linear or non-linear manner to achieve the best performance of the FGM piezoelectric actuator. The analytical and FEM results are found to agree well with the experimental measurements for both rectangular and disk actuators. CLT solutions are found to coincide well with the elasticity solutions for high aspect ratios while the CLT solutions gave poor results compared to the 2D elasticity solutions for

  8. Particle behavior in solid propellant rockets

    NASA Technical Reports Server (NTRS)

    Netzer, D. W.; Diloreto, V. D.; Dubrov, E.

    1980-01-01

    The use of holography, high speed motion pictures, light scattering measurements, and post-fire particle collection/scanning electron microscopic examination to study the combustion of composite solid propellants is discussed. The relative advantages and disadvantages of the different experimental techniques for obtaining two-phase flow characteristics within the combustion environment of a solid propellant grain are evaluated. Combustion bomb studies using high speed motion pictures and post-fire residue analysis were completed for six low metal content propellants. Resolution capabilities and the relationships between post-fire residue and motion picture data are determined. Initial testing using a holocamera together with a 2D windowed motor is also described.

  9. Particle size reduction of propellants by cryocycling

    SciTech Connect

    Whinnery, L.; Griffiths, S.; Lipkin, J.

    1995-05-01

    Repeated exposure of a propellant to liquid nitrogen causes thermal stress gradients within the material resulting in cracking and particle size reduction. This process is termed cryocycling. The authors conducted a feasibility study, combining experiments on both inert and live propellants with three modeling approaches. These models provided optimized cycle times, predicted ultimate particle size, and allowed crack behavior to be explored. Process safety evaluations conducted separately indicated that cryocycling does not increase the sensitivity of the propellants examined. The results of this study suggest that cryocycling is a promising technology for the demilitarization of tactical rocket motors.

  10. Metered-dose inhaler formulations with beclomethasone-17,21-dipropionate using the ozone friendly propellant R 134a.

    PubMed

    Steckel, H; Müller, B W

    1998-07-01

    Metered-dose inhalers (MDI) are the most widely prescribed devices in the treatment of lung diseases but the continued use of chlorofluorocarbons (CFC) as propellants has made them unpopular due to their influence on the stratospheric ozone layer. The purpose of this study was to show possibilities of formulating beclomethasone-17,21-dipropionate (BDP) with the alternative propellant R 134a as a solution or as a suspension-type metered-dose inhaler. Influencing factors such as surfactant concentration, cosolvent content and actuator tube design were investigated. Metered-dose inhaler formulations were manufactured using a pressure filling technique. The resulting formulations were characterized with regard to their emitted fine particle fraction using the two-stage impinger, BP 93. Fine particle fraction was found to be independent on the surfactant concentration but highly dependent on the cosolvent content and the actuator tube design. In vitro fine particle fractions of 50% were obtained with solution phase MDIs. Formulating BDP as a suspension resulted in unstable dispersions in most cases because of the partial solubility of the drug in the liquified propellant. Stable suspension formulations gave an in vitro fine particle fraction of about 30%. A comparison with established marketed BDP suspension formulations which were found to emit a fine particle fraction in the range 10-50% showed the equivalence of the new CFC-free formulations.

  11. 14 CFR 25.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering controls. 25.1153... Accessories § 25.1153 Propeller feathering controls. (a) There must be a separate propeller feathering control for each propeller. The control must have means to prevent its inadvertent operation. (b)...

  12. 14 CFR 23.907 - Propeller vibration and fatigue.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a) The applicant must determine the magnitude of the propeller...

  13. 14 CFR 23.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller feathering controls. 23.1153... Powerplant Controls and Accessories § 23.1153 Propeller feathering controls. If there are propeller feathering controls installed, it must be possible to feather each propeller separately. Each control...

  14. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1)...

  15. 14 CFR 23.33 - Propeller speed and pitch limits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch limits. 23.33... Propeller speed and pitch limits. (a) General. The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions. (b) Propellers not controllable in...

  16. 14 CFR 25.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller feathering controls. 25.1153... Accessories § 25.1153 Propeller feathering controls. (a) There must be a separate propeller feathering control for each propeller. The control must have means to prevent its inadvertent operation. (b)...

  17. 14 CFR 25.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller feathering controls. 25.1153... Accessories § 25.1153 Propeller feathering controls. (a) There must be a separate propeller feathering control for each propeller. The control must have means to prevent its inadvertent operation. (b)...

  18. 14 CFR 35.43 - Propeller hydraulic components.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller hydraulic components. 35.43... AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.43 Propeller hydraulic components. Applicants must show by test, validated analysis, or both, that propeller components that contain...

  19. 14 CFR 25.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller feathering controls. 25.1153... Accessories § 25.1153 Propeller feathering controls. (a) There must be a separate propeller feathering control for each propeller. The control must have means to prevent its inadvertent operation. (b)...

  20. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1)...

  1. 14 CFR 23.33 - Propeller speed and pitch limits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch limits. 23.33... Propeller speed and pitch limits. (a) General. The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions. (b) Propellers not controllable in...

  2. 14 CFR 25.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller feathering controls. 25.1153... Accessories § 25.1153 Propeller feathering controls. (a) There must be a separate propeller feathering control for each propeller. The control must have means to prevent its inadvertent operation. (b)...

  3. 14 CFR 35.43 - Propeller hydraulic components.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller hydraulic components. 35.43... AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.43 Propeller hydraulic components. Applicants must show by test, validated analysis, or both, that propeller components that contain...

  4. 14 CFR 23.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller feathering controls. 23.1153... Powerplant Controls and Accessories § 23.1153 Propeller feathering controls. If there are propeller feathering controls installed, it must be possible to feather each propeller separately. Each control...

  5. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Variable and reversible pitch propellers... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and reversible pitch propellers. (a) No single failure or malfunction in the propeller system will result...

  6. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller ratings and operating limitations... AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and operating limitations must: (1) Be established by the applicant and approved by...

  7. 14 CFR 23.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller feathering controls. 23.1153... Powerplant Controls and Accessories § 23.1153 Propeller feathering controls. If there are propeller feathering controls installed, it must be possible to feather each propeller separately. Each control...

  8. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller ratings and operating limitations... AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and operating limitations must: (1) Be established by the applicant and approved by...

  9. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Variable and reversible pitch propellers... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and reversible pitch propellers. (a) No single failure or malfunction in the propeller system will result...

  10. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller ratings and operating limitations... AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and operating limitations must: (1) Be established by the applicant and approved by...

  11. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Variable and reversible pitch propellers... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and reversible pitch propellers. (a) No single failure or malfunction in the propeller system will result...

  12. 14 CFR 23.907 - Propeller vibration and fatigue.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a) The applicant must determine the magnitude of the propeller...

  13. 14 CFR 23.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller feathering controls. 23.1153... Powerplant Controls and Accessories § 23.1153 Propeller feathering controls. If there are propeller feathering controls installed, it must be possible to feather each propeller separately. Each control...

  14. 14 CFR 23.907 - Propeller vibration and fatigue.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a) The applicant must determine the magnitude of the propeller...

  15. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller ratings and operating limitations... AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and operating limitations must: (1) Be established by the applicant and approved by...

  16. 14 CFR 35.43 - Propeller hydraulic components.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller hydraulic components. 35.43... AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.43 Propeller hydraulic components. Applicants must show by test, validated analysis, or both, that propeller components that contain...

  17. 14 CFR 23.907 - Propeller vibration and fatigue.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a) The applicant must determine the magnitude of the propeller...

  18. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Variable and reversible pitch propellers... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and reversible pitch propellers. (a) No single failure or malfunction in the propeller system will result...

  19. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1)...

  20. 14 CFR 35.16 - Propeller critical parts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller critical parts. 35.16 Section 35... AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.16 Propeller critical parts. The integrity of each propeller critical part identified by the safety analysis required by § 35.15 must be...

  1. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1)...

  2. 14 CFR 35.21 - Variable and reversible pitch propellers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Variable and reversible pitch propellers... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Design and Construction § 35.21 Variable and reversible pitch propellers. (a) No single failure or malfunction in the propeller system will result...

  3. 14 CFR 35.43 - Propeller hydraulic components.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller hydraulic components. 35.43... AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.43 Propeller hydraulic components. Applicants must show by test, validated analysis, or both, that propeller components that contain...

  4. 14 CFR 35.5 - Propeller ratings and operating limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller ratings and operating limitations... AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS General § 35.5 Propeller ratings and operating limitations. (a) Propeller ratings and operating limitations must: (1) Be established by the applicant and approved by...

  5. 14 CFR 23.907 - Propeller vibration and fatigue.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller vibration and fatigue. 23.907... General § 23.907 Propeller vibration and fatigue. This section does not apply to fixed-pitch wood propellers of conventional design. (a) The applicant must determine the magnitude of the propeller...

  6. 14 CFR 23.33 - Propeller speed and pitch limits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch limits. 23.33... Propeller speed and pitch limits. (a) General. The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions. (b) Propellers not controllable in...

  7. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1)...

  8. 14 CFR 23.1153 - Propeller feathering controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller feathering controls. 23.1153... Powerplant Controls and Accessories § 23.1153 Propeller feathering controls. If there are propeller feathering controls installed, it must be possible to feather each propeller separately. Each control...

  9. 14 CFR 23.33 - Propeller speed and pitch limits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch limits. 23.33... Propeller speed and pitch limits. (a) General. The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions. (b) Propellers not controllable in...

  10. 14 CFR 23.33 - Propeller speed and pitch limits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch limits. 23.33... Propeller speed and pitch limits. (a) General. The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions. (b) Propellers not controllable in...

  11. Enhanced actuation of nanocrystalline diamond microelectromechanical disk resonators with AlN layers

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Taro; Reusch, Markus; Holc, Katarzyna; Iankov, Dimitre; Zuerbig, Verena; Zukauskaite, Agne; Nebel, Christoph E.; Ambacher, Oliver; Lebedev, Vadim

    2016-04-01

    A great potential of the use of aluminum nitride (AlN) to enhance the actuation of nanocrystalline diamond (NCD) microelectromechanical system disk resonators is revealed. A disk resonator with a unimorph (AlN/NCD) structure is fabricated by depositing a c-axis oriented AlN on a capacitive NCD disk resonator. The unimorph resonator is piezoelectrically actuated with flexural whispering gallery modes with a relatively large electrode gap spacing, i.e., the spacing which is greater than 1 μm, although this is not possible for the capacitive NCD disk resonator. This result is explained by a finite element method simulation where the piezoelectric actuation turns out to be more effective than the capacitive actuation when the electrode gap spacing is >0.8 μm. The simulation also shows that the electrode gap spacing required for the capacitive actuation to be more effective than the piezoelectric actuation exponentially decreases when the resonator dimension is scaled down for higher frequency operations. Our study indicates that the use of AlN is promising to decrease impedance levels of NCD disk resonators especially for their higher frequency operations.

  12. Demonstration of Separation Control Using Glow-Discharge Plasma Actuators

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.; Ashpis, David E.

    2003-01-01

    Active flow control of boundary-layer separation using glow-discharge plasma actuators is studied experimentally. Separation is induced on a flat plate installed in a closed-circuit wind tunnel by a shaped insert on the opposite wall. The flow conditions represent flow over the suction surface of a modem low-pressure-turbine airfoil. The Reynolds number, based on wetted plate length and nominal exit velocity, is varied from 50,000 to 300,000, covering cruise to takeoff conditions. Low (0.2%) and high (2.5%) free-stream turbulence intensities are set using passive grids. A spanwise-oriented phased-plasma-array actuator, fabricated on a printed circuit board, is surface-flush-mounted upstream of the separation point and can provide forcing in a wide frequency range. Static surface pressure measurements and hot-wire anemometry of the base and controlled flows are performed and indicate that the glow-discharge plasma actuator is an effective device for separation control.

  13. Demonstration of Separation Delay with Glow-Discharge Plasma Actuators

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.; Ashpis, David E.

    2004-01-01

    Active flow control of boundary-layer separation using glow-discharge plasma actuators is studied experimentally. Separation is induced on a flat plate installed in a closed-circuit wind tunnel by a shaped insert on the opposite wall. The flow conditions represent flow over the suction surface of a modern low-pressure-turbine airfoil. The Reynolds number, based on wetted plate length and nominal exit velocity, is varied from 50,000 to 300,000, covering cruise to takeoff conditions. Low (0.2 percent) and high (2.5 percent) free-stream turbulence intensities are set using passive grids. A spanwise-oriented phased-plasma-array actuator, fabricated on a printed circuit board, is surface-flush-mounted upstream of the separation point and can provide forcing in a wide frequency range. Static surface pressure measurements and hot-wire anemometry of the base and controlled flows are performed and indicate that the glow-discharge plasma actuator is an effective device for separation control.

  14. Mass and charge transport in IPMC actuators with fractal interfaces

    NASA Astrophysics Data System (ADS)

    Chang, Longfei; Wu, Yucheng; Zhu, Zicai; Li, Heng

    2016-04-01

    Ionic Polymer-Metal Composite (IPMC) actuators have been attracting a growing interest in extensive applications, which consequently raises the demands on the accuracy of its theoretical modeling. For the last few years, rough landscape of the interface between the electrode and the ionic membrane of IPMC has been well-documented as one of the key elements to ensure a satisfied performance. However, in most of the available work, the interface morphology of IPMC was simplified with structural idealization, which lead to perplexity in the physical interpretation on its interface mechanism. In this paper, the quasi-random rough interface of IPMC was described with fractal dimension and scaling parameters. And the electro-chemical field was modeled by Poisson equation and a properly simplified Nernst-Planck equation set. Then, by simulation with Finite Element Method, a comprehensive analysis on he inner mass and charge transportation in IPMC actuators with different fractal interfaces was provided, which may be further adopted to instruct the performance-oriented interface design for ionic electro-active actuators. The results also verified that rough interface can impact the electrical and mechanical response of IPMC, not only from the respect of the real surface increase, but also from mass distribution difference caused by the complexity of the micro profile.

  15. Reducing aerodynamic vibration with piezoelectric actuators: a genetic algorithm optimization

    NASA Astrophysics Data System (ADS)

    Hu, Zhenning; Jakiela, Mark; Pitt, Dale M.; Burnham, Jay K.

    2004-07-01

    Modern high performance aircraft fly at high speeds and high angles of attack. This can result in "buffet" aerodynamics, an unsteady turbulent flow that causes vibrations of the wings, tails, and body of the aircraft. This can result in decreased performance and ride quality, and fatigue failures. We are experimenting with controlling these vibrations by using piezoceramic actuators attached to the inner and outer skin of the aircraft. In this project, a tail or wing is investigated. A "generic" tail finite element model is studied in which individual actuators are assumed to exactly cover individual finite elements. Various optimizations of the orientations and power consumed by these actuators are then performed. Real coded genetic algorithms are used to perform the optimizations and a design space approximation technique is used to minimize costly finite element runs. An important result is the identification of a power consumption threshold for the entire system. Below the threshold, vibration control performance of optimized systems decreases with decreasing values of power supplied to the entire system.

  16. On the design and test of a low noise propeller

    NASA Technical Reports Server (NTRS)

    Succi, G. P.

    1981-01-01

    An extensive review of noise and performance of general aviation propellers was performed. Research was done in three areas: The acoustic and aerodynamic theory of general aviation propellers, wind tunnel tests of three one-quarter scale models of general aviation propellers, and flight test of two low noise propellers. The design and testing of the second propeller is reviewed. The general aerodynamic considerations needed to design a new propeller are described. The design point analysis of low noise propellers is reviewed. The predicted and measured noise levels are compared.

  17. Silkworm protein: its possibility as an actuator

    NASA Astrophysics Data System (ADS)

    Jin, Hyoung-Joon; Myung, Seung Jun; Kim, Heung Soo; Jung, Woochul; Kim, Jaehwan

    2006-03-01

    The possibility of silkworm (Bombyx mori) protein as a base material of biomimetic actuator was investigated in this paper. Silkworm films were prepared from high concentrations of regenerated fibroin in aqueous solution. Films with thickness of about 100 μm were prepared for coating electrodes. The cast silk films were coated by very thin gold electrode on both sides of the film. Tensile test of cast film showed bi-modal trend, which is typical stress-strain relation of polymeric film. As the test of a possible biomimetic actuator, silkworm film actuator provides bending deformations according to the magnitude and frequency of the applied electric filed. Although the present bending deformation of silkworm film actuator is smaller than that of Electro-Active Paper actuator, it provides the possibility of biomimetic actuator.

  18. Microwave Power for Smart Membrane Actuators

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Song, Kyo D.; Golembiewski, Walter T.; Chu, Sang-Hyon; King, Glen C.

    2002-01-01

    The concept of microwave-driven smart membrane actuators is envisioned as the best option to alleviate the complexity associated with hard-wired control circuitry. A large, ultra-light space structure, such as solar sails and Gossamer spacecrafts, requires a distribution of power into individual membrane actuators to control them in an effective way. A patch rectenna array with a high voltage output was developed to drive smart membrane actuators. Networked patch rectenna array receives and converts microwave power into a DC power for an array of smart actuators. To use microwave power effectively, the concept of a power allocation and distribution (PAD) circuit is developed and tested for networking a rectenna/actuator patch array. For the future development, the PAD circuit could be imbedded into a single embodiment of rectenna and actuator array with the thin-film microcircuit embodiment. Preliminary design and fabrication of PAD circuitry that consists of a sixteen nodal elements were made for laboratory testing.

  19. Electromechanical actuator for thrust vector control

    NASA Astrophysics Data System (ADS)

    Zubkow, Zygmunt

    Attention is given to the development and testing of electromechanical actuator (EMA) systems for use in first- and second-stage thrust vector control of rocket engines. An overview of the test program is also presented. Designs for both first- and second-stage actuators employ redundant dc brushless, three-phase rare-earth permanent magnet motors. The first-stage actuator is about 28 hp per motor and uses a roller screw. Second-stage thrust vector control is implemented with a much smaller actuator of about 1 hp per motor. This actuator uses a gear drive with a recycling ball screw mechanism. An operational EMA is presented. This 6.5-in. actuator is capable of a stall force of 1350 pounds per motor and a frequency response of about 5 HZ.

  20. Integrated sensing and actuation of muscle-like actuators

    NASA Astrophysics Data System (ADS)

    Gisby, T. A.; Xie, S.; Calius, E. P.; Anderson, I. A.

    2009-03-01

    The excellent overall performance and compliant nature of Dielectric Elastomer Actuators (DEAs) make them ideal candidates for artificial muscles. Natural muscle however is much more than just an actuator, it provides position feedback to the brain that is essential for the body to maintain balance and correct posture. If DEAs are to truly earn the moniker of "artificial muscles" they need to be able to reproduce, if not improve on, this functionality. Self-sensing DEAs are the ideal solution to this problem. This paper presents a system by which the capacitance of a DEA can be sensed while it is being actuated and used for feedback control. This system has been strongly influenced by the desire for portability i.e. designed for use in a battery operated microcontroller based system. It is capable of controlling multiple independent DEAs using a single high voltage power supply. These features are important developments for artificial muscle devices where accuracy and low mass are important e.g. a prosthetic hand or force-feedback surgical tools. A numerical model of the electrical behaviour of the DEA that incorporates arbitrary leakage currents and the impact of arbitrary variable capacitance has been created to model a DEA system. A robust capacitive self-sensing method that uses a slew-rate controlled Pulse Width Modulation (PWM) signal and compensates for the effects of leakage current and variable capacitance is presented. The numerical model is then used to compare the performance of this new method with an earlier method previously published by the authors.