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Sample records for pipes conveying pulsating

  1. Transition to turbulence in pulsating pipe flow

    NASA Astrophysics Data System (ADS)

    Xu, Duo; Warnecke, Sascha; Hof, Bjoern; Avila, Marc

    2014-11-01

    We report an experimental investigation of the transition to turbulence in a pulsating pipe flow. This flow is a prototype of various pulsating flows in both nature and engineering, such as in the cardiovascular system where the onset of turbulence is often possibly related to various diseases (e.g., the formation of aneurysms). The experiments are carried out in a straight rigid pipe using water with a sinusoidal modulation of the flow rate. The governing parameters, Reynolds number, Womersley number α (dimensionless pulsating frequency) and the pulsating amplitude A, cover a wide range 3 < α < 23 and 0 < A < 1 . To characterize the transition to turbulence, we determine how the characteristic lifetime of turbulent spots (/puffs) are affected by the pulsation. While at high pulsation frequencies (α > 12) lifetimes of turbulent spots are entirely unaffected by the pulsation, at lower frequencies they are substantially affected. With decreasing frequency much larger Reynolds numbers are needed to obtain spots of the same characteristic lifetime. Hence at low frequency transition is delayed significantly. In addition the effect of the pulsation amplitude on the transition delay is quantified. Duo Xu would like to acknowledge the support from Humboldt Foundation.

  2. Modeling of pulsating heat pipes.

    SciTech Connect

    Givler, Richard C.; Martinez, Mario J.

    2009-08-01

    This report summarizes the results of a computer model that describes the behavior of pulsating heat pipes (PHP). The purpose of the project was to develop a highly efficient (as compared to the heat transfer capability of solid copper) thermal groundplane (TGP) using silicon carbide (SiC) as the substrate material and water as the working fluid. The objective of this project is to develop a multi-physics model for this complex phenomenon to assist with an understanding of how PHPs operate and to be able to understand how various parameters (geometry, fill ratio, materials, working fluid, etc.) affect its performance. The physical processes describing a PHP are highly coupled. Understanding its operation is further complicated by the non-equilibrium nature of the interplay between evaporation/condensation, bubble growth and collapse or coalescence, and the coupled response of the multiphase fluid dynamics among the different channels. A comprehensive theory of operation and design tools for PHPs is still an unrealized task. In the following we first analyze, in some detail, a simple model that has been proposed to describe PHP behavior. Although it includes fundamental features of a PHP, it also makes some assumptions to keep the model tractable. In an effort to improve on current modeling practice, we constructed a model for a PHP using some unique features available in FLOW-3D, version 9.2-3 (Flow Science, 2007). We believe that this flow modeling software retains more of the salient features of a PHP and thus, provides a closer representation of its behavior.

  3. Transition to turbulence in pulsating pipe flow

    NASA Astrophysics Data System (ADS)

    Hof, Bjorn; Warnecke, Sascha; Xu, Duo

    2013-11-01

    We report an experimental study of the transition to turbulence in a pulsating pipe flow the most important example of pulsating flows is the cardiovascular system where the onset of fluctuations and turbulence can be a possible cause for various diseases such as the formation of aneurysms. The present study is limited to a straight rigid pipe, sinusoidal modulation of the flow rate and a Newtonian fluid. The dimensionless parameters (Womersley and Reynolds numbers) were chosen to include the parameter range encountered in larger arteries. We observe that at large frequencies the critical point for the onset of turbulence remains completely unaffected by pulsation for all amplitudes investigated (up to 40%). However for smaller frequencies (Womersley numbers below 10) the critical point considerably increases. Furthermore we investigate how the transition scenario is affected for a fixed frequency and increasing amplitudes (approaching oscillatory flow).

  4. Flow induced pulsations in pipe systems

    NASA Astrophysics Data System (ADS)

    Bruggeman, Jan Cornelis

    1987-12-01

    The aeroacoustic behavior of a low Mach number, high Reynolds number flow through a pipe with closed side branches was investigated. Sound is generated by coherent structures of concentrated vorticity formed periodically in the separated flow in the T-shaped junctions of side branches and the main pipe. The case of moderate pulsation amplitudes was investigated. It appears that the vortical flow in a T-joint is an aeroacoustic source of constant strength when acoustic energy losses due to radiation and friction are small but not negligible. When acoustic energy losses due to radiation and friction are negligible, the nonlinear character of vortex damping is the amplitude limiting mechanism. It is stressed that aeroacoustic sources should not be neglected in studies of the response of a piping lay-out with flow to, e.g., the pulsating output of a compressor.

  5. Design of a Hydrogen Pulsating Heat Pipe

    NASA Astrophysics Data System (ADS)

    Liu, Yumeng; Deng, Haoren; Pfotenhauer, John; Gan, Zhihua

    In order to enhance the application of a cryocooler that provides cooling capacity at the cold head location, and effectively spread that cooling over an extended region, one requires an efficient heat transfer method. The pulsating heat pipe affords a highly effective heat transfer component that has been extensively researched at room temperature, but is recently being investigated for cryogenic applications. This paper describes the design. The experimental setup is designed to characterize the thermal performance of the PHP as a function of the applied heat, number of turns, filling ratio, inclination angle, and length of adiabatic section.

  6. Computational model of miniature pulsating heat pipes.

    SciTech Connect

    Martinez, Mario J.; Givler, Richard C.

    2013-01-01

    The modeling work described herein represents Sandia National Laboratories (SNL) portion of a collaborative three-year project with Northrop Grumman Electronic Systems (NGES) and the University of Missouri to develop an advanced, thermal ground-plane (TGP), which is a device, of planar configuration, that delivers heat from a source to an ambient environment with high efficiency. Work at all three institutions was funded by DARPA/MTO; Sandia was funded under DARPA/MTO project number 015070924. This is the final report on this project for SNL. This report presents a numerical model of a pulsating heat pipe, a device employing a two phase (liquid and its vapor) working fluid confined in a closed loop channel etched/milled into a serpentine configuration in a solid metal plate. The device delivers heat from an evaporator (hot zone) to a condenser (cold zone). This new model includes key physical processes important to the operation of flat plate pulsating heat pipes (e.g. dynamic bubble nucleation, evaporation and condensation), together with conjugate heat transfer with the solid portion of the device. The model qualitatively and quantitatively predicts performance characteristics and metrics, which was demonstrated by favorable comparisons with experimental results on similar configurations. Application of the model also corroborated many previous performance observations with respect to key parameters such as heat load, fill ratio and orientation.

  7. Heat transfer characteristics of pulsated turbulent pipe flow

    NASA Astrophysics Data System (ADS)

    Habib, M. A.; Said, S. A. M.; Al-Farayedhi, A. A.; Al-Dini, S. A.; Asghar, A.; Gbadebo, S. A.

    Heat Transfer characteristics of pulsated turbulent pipe flow under different conditions of pulsation frequency, amplitude and Reynolds number were experimentally investigated. The pipe wall was kept at uniform heat flux. Reynolds number was varied from 5000 to 29 000 while frequency of pulsation ranged from 1 to 8 Hz. The results show an enhancement in the local Nusselt number at the entrance region. The rate of enhancement decreased as Re increased. Reduction of heat transfer coefficient was observed at higher frequencies and the effect of pulsation is found to be significant at high Reynolds number. It can be concluded that the effect of pulsation on the mean Nusselt numbers is insignificant at low values of Reynolds number.

  8. Convective heat transfer characteristics of laminar pulsating pipe air flow

    NASA Astrophysics Data System (ADS)

    Habib, M. A.; Attya, A. M.; Eid, A. I.; Aly, A. Z.

    Heat transfer characteristics to laminar pulsating pipe flow under different conditions of Reynolds number and pulsation frequency were experimentally investigated. The tube wall of uniform heat flux condition was considered. Reynolds number was varied from 780 to 1987 while the frequency of pulsation ranged from 1 to 29.5Hz. The results showed that the relative mean Nusselt number is strongly affected by pulsation frequency while it is slightly affected by Reynolds number. The results showed enhancements in the relative mean Nusselt number. In the frequency range of 1-4Hz, an enhancement up to 30% (at Reynolds number of 1366 and pulsation frequency of 1.4Hz) was obtained. In the frequency range of 17-25Hz, an enhancement up to 9% (at Reynolds number of 1366 and pulsation frequency of 17.5Hz) was indicated. The rate of enhancement of the relative mean Nusselt number decreased as pulsation frequency increased or as Reynolds number increased. A reduction in relative mean Nusselt number occurred outside these ranges of pulsation frequencies. A reduction in relative mean Nusselt number up to 40% for pulsation frequency range of 4.1-17Hz and a reduction up to 20% for pulsation frequency range of 25-29.5Hz for Reynolds numbers range of 780-1987 were considered. This reduction is directly proportional to the pulsation frequency. Empirical dimensionless equations have been developed for the relative mean Nusselt number that related to Reynolds number (750

  9. Experimental investigation of coarse particle conveying in pipes

    NASA Astrophysics Data System (ADS)

    Vlasak, Pavel; Chara, Zdenek; Konfrst, Jiri; Krupička, Jan

    2015-05-01

    The advanced knowledge of particle-water mixture flow behaviour is important for safe, reliable, and economical design and operation of the freight pipelines. The effect of the mixture velocity and concentration on the coarse particle - water mixtures flow behaviour was experimentally investigated on an experimental pipe loop of inner diameter D = 100 mm with horizontal, vertical, and inclined pipe sections. Narrow particle size distribution basalt pebbles were used as model of coarse-grained solid particles. The radiometric method was used to measure particle concentration distribution in pipe cross-section. Mixture flow behaviour and particles motion along the pipe invert were studied in a pipe viewing section. The study revealed that the coarse particlewater mixtures in the horizontal and inclined pipe sections were significantly stratified. The particles moved principally in a layer close to the pipe invert. However, for higher and moderate flow velocities the particles moved also in the central part of the pipe cross-section, and particle saltation was found to be dominant mode of particle conveying.

  10. Experimental investigation on a pulsating heat pipe with hydrogen

    NASA Astrophysics Data System (ADS)

    Deng, H. R.; Liu, Y. M.; Ma, R. F.; Han, D. Y.; Gan, Z. H.; Pfotenhauer, J. M.

    2015-12-01

    The pulsating heat pipe (PHP) has been increasingly studied in cryogenic application, for its high transfer coefficient and quick response. Compared with Nb3Sn and NbTi, MgB2 whose critical transformation temperature is 39 K, is expected to replace some high-temperature superconducting materials at 25 K. In order to cool MgB2, this paper designs a Hydrogen Pulsating Heat Pipe, which allows a study of applied heat, filling ratio, turn number, inclination angle and length of adiabatic section on the thermal performance of the PHP. The thermal performance of the hydrogen PHP is investigated for filling ratios of 35%, 51%, 70% at different heat inputs, and provides information regarding the starting process is received at three filling ratios.

  11. Experimental research on heat transfer of pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Li, Jia; Yan, Li

    2008-06-01

    Experimental research was conducted to understand heat transfer characteristic of pulsating heat pipe in this paper, and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appears in top heating condition. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred from bulk flow to semi-annular flow and annular flow, and the performance of heat transfer is improved for down heating case. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

  12. Influence of gravity on flutter of cantilevered pipes conveying fluid

    NASA Astrophysics Data System (ADS)

    Rivero, Javier; Perez-Saborid, Miguel

    2012-11-01

    We have considered the dynamics of the nonlinear interaction between a flexible pipe and the conveyed fluid in the presence of gravity. The stability of the system (fllutter and buckling) depends on parameters such as the dimensionless fluid flow rate, the gravity to bending stiffness ratio and the fluid to pipe mass ratio and it has been studied in detail both numerically and experimentally. It has also been found that the stabilizing or destabilizing effects of fluid flow depends crucially on the direction of gravity respect to the undeformed midline of the pipe. We have also computed the post-critical behavior of the system by solving the full nonlinear equations of the problem and analyzed the transfer of energy within the system in the nonlinear regime. We have formulated the problem in terms of the angles of the midline of the pipe instead of its transverse displacements, so that we can deal with large deflections without recurring to the quasi-linear approximations concerning the pipe curvature usually made in the literature. Supported by the Ministerio de Educación, Cultura y Deportes of Spain under grant DPI 2010-20450 C03-02.

  13. Instabilities of a spatial system of articulated pipes conveying fluid

    NASA Technical Reports Server (NTRS)

    Bohn, M. P.; Herrmann, G.

    1974-01-01

    A spatial system of two articulated pipes conveying fluid is examined analytically and experimentally. As the flow rate is increased, stable equilibrium may be lost by either divergence (static buckling) or by flutter (oscillations with increasing amplitude), depending upon the value of an angle beta which measures the 'out-of-planeness' of the system. It is found that in the range O less than beta less than 90 deg there exists a transition value below which stability is lost by flutter and above which stability is lost by divergence.

  14. A Novel Pre-cooling System for a Cryogenic Pulsating Heat Pipe

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Liu, Huiming; Gong, Linghui; Xu, Xiangdong; Li, Laifeng

    To reduce the influence of the pipe material on the measurement of effective thermal conductivity, the pipe of a cryogenic pulsating heat pipe is generally made of stainless steel. Because of the low thermal conductivity of stainless steel, the pre-cooling of the evaporator in cryogenic pulsating heat pipe using helium as working fluid at 4.2 K is a problem. We designed a mechanical-thermal switch between the cryocooler and the evaporator, which was on during the pre-cooling process and off during the test process. By using the pre-cooling system, the cool down time of the cryogenic pulsating heat pipe was reduced significantly.

  15. Experimental study on the start up performance of flat plate pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Hu, Chaofa; Jia, Li

    2011-06-01

    An experimental system of flat plate pulsating heat pipe was established and experimental research was carried out in this system to know the mechanism of heat transfer, start-up and operating characteristics. The factors, such as filling rate, heating power, heating method etc, which have great influence on the thermal performance of the plate pulsating heat pipe were discussed. The results indicate that heating power and filling rate are the important factors for the start-up of the plate pulsating heat pipe. The different start-up power is needed with different filling rate, and the start-up of the heat pipe in case of bottom heated is much easier than that of top heated. Increasing the heating power and enlarging the heating area can make the start-up easier. Heating power can also affect the start-up time of heat pipe under the condition of bottom heated, while it does not have some influence to the heat pipe of top heated. The thermal resistance of plate pulsating heat pipe is related with the heating power, and the higher the heating power is, the smaller the thermal resistance is. But the best filling rate which the heat pipe needs is different with different heating methods, and the performance of the heat pipe in the case of bottom heated is better than the others.

  16. Heat transfer mechanisms in pulsating heat-pipes with nanofluid

    NASA Astrophysics Data System (ADS)

    Gonzalez, Miguel; Kelly, Brian; Hayashi, Yoshikazu; Kim, Yoon Jo

    2015-01-01

    In this study, the effect of silver nanofluid on a pulsating heat-pipe (PHP) thermal performance was experimentally investigated to figure out how nanofluid works with PHP. A closed loop PHP was built with 3 mm diameter tubes. Thermocouples and pressure transducers were installed for fluid and surface temperature and pressure measurements. The operating temperature of the PHP varied from 30-100 °C, with power rates of 61 W and 119 W. The fill ratio of 30%, 50%, and 70% were tested. The results showed that the evaporator heat transfer performance was degraded by the addition of nanoparticles due to increased viscosity at high power rate, while the positive effects of high thermal conductivity and enhanced nucleate boiling worked better at low power rate. In the condenser section, owing to the relatively high liquid content, nanofluid more effectively improved the heat transfer performance. However, since the PHP performance was dominantly affected by evaporator heat transfer performance, the overall benefit of enhanced condenser section performance was greatly limited. It was also observed that the poor heat transfer performance with nanofluid at the evaporator section led to lower operating pressure of PHP.

  17. A helium based pulsating heat pipe for superconducting magnets

    NASA Astrophysics Data System (ADS)

    Fonseca, Luis Diego; Miller, Franklin; Pfotenhauer, John

    2014-01-01

    This study was inspired to investigate an alternative cooling system using a helium-based pulsating heat pipes (PHP), for low temperature superconducting magnets. In addition, the same approach can be used for exploring other low temperature applications. The advantages of PHP for transferring heat and smoothing temperature profiles in various room temperature applications have been explored for the past 20 years. An experimental apparatus has been designed, fabricated and operated and is primarily composed of an evaporator and a condenser; in which both are thermally connected by a closed loop capillary tubing. The main goal is to measure the heat transfer properties of this device using helium as the working fluid. The evaporator end of the PHP is comprised of a copper winding in which heat loads up to 10 watts are generated, while the condenser is isothermal and can reach 4.2 K via a two stage Sumitomo RDK408A2 GM cryocooler. Various experimental design features are highlighted. Additionally, performance results in the form of heat transfer and temperature characteristics are provided as a function of average condenser temperature, PHP fill ratio, and evaporator heat load. Results are summarized in the form of a dimensionless correlation and compared to room temperature systems. Implications for superconducting magnet stability are highlighted.

  18. Experimental study on rack cooling system based on a pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Lu, Qianyi; Jia, Li

    2016-02-01

    A rack cooling system based on a large scale flat plate pulsating heat pipe is proposed. The heat generated from IT equipment in a closed rack is transferred by the rear door pulsating heat pipe to the chilled air passage and is avoided to release into the room. The influence of the start-up performance of the heat pipe, the load of the rack and the load dissipation to the temperature and the velocity distribution in the rack are discussed. It is found that the temperature would be lower and the temperature distribution would be more uniform in the rack when the pulsating heat pipe is in operation. Also, the effect of rack electricity load on temperature distribution is analyzed. It is indicated that higher velocity of chilled air will improve heat transfer of the rack.

  19. A contribution to the stability of an overhanging pipe conveying fluid

    NASA Astrophysics Data System (ADS)

    De Bellis, Maria Laura; Ruta, Giuseppe C.; Elishakoff, Isaac

    2015-09-01

    We investigate the dynamic stability of a pipe that conveys fluid, clamped or pinned at one end and with an intermediate support, thus exhibiting an overhang. The model of the pipe incorporates both Euler-Bernoulli and Bresse-Timoshenko schemes as well as transverse inertia. Material and external damping mechanisms are taken into account, while the conveyed fluid is supposed to be in fully turbulent flow. The pipe can rest on a linear elastic Winkler soil. The influence of all the physical quantities and of the overhang length on the critical velocity of the fluid front is investigated. Some numerical results are presented and discussed.

  20. An experimental investigation of heat transfer to pulsating pipe air flow with different amplitudes

    NASA Astrophysics Data System (ADS)

    Zohir, A. E.; Habib, M. A.; Attya, A. M.; Eid, A. I.

    2006-05-01

    Heat transfer characteristics to both laminar and turbulent pulsating pipe flows under different conditions of Reynolds number, pulsation frequency, pulsator location and tube diameter were experimentally investigated. The tube wall of uniform heat flux condition was considered for both cases. Reynolds number varied from 750 to 12,320 while the frequency of pulsation ranged from 1 to 10 Hz. With locating the pulsator upstream of the inlet of the test section tube, results showed an increase in heat transfer rate due to pulsation by as much as 30% with flow Reynolds number of 1,643 and pulsation frequency of 1 Hz, depending on the upstream location of the pulsator valve. Closer the valve to the tested section inlet, the better improvement in the heat transfer coefficient is achieved. Upon comparing the heat transfer results of the upstream and the downstream pulsation, at Reynolds number of 1,366 and 1,643, low values of the relative mean Nusselt number were obtained with the upstream pulsation. Comparing the heat transfer results of the two studied test sections tubes for Reynolds number range from 8,000 to 12,000 and pulsation frequency range from 1.0 to 10 Hz showed that more improvement in heat transfer rate was observed with a larger tube diameter. For Reynolds number ranging from 8,000 to 12,000 and pulsation frequency of 10 Hz, an improvement in the relative mean Nusselt number of about 50% was obtained at Reynolds number of 8,000 for the large test section diameter of 50 mm. While, for the small test section diameter of 15 mm, at same conditions of Reynolds number and frequency, a reduction in the relative mean Nusselt number of up to 10% was obtained.

  1. Experimental study on heat transfer performance of pulsating heat pipe with refrigerants

    NASA Astrophysics Data System (ADS)

    Wang, Xingyu; Jia, Li

    2016-10-01

    The effects of different refrigerants on heat transfer performance of pulsating heat pipe (PHP) are investigated experimentally. The working temperature of pulsating heat pipe is kept in the range of 20°C-50°C. The startup time of the pulsating heat pipe with refrigerants can be shorter than 4 min, when heating power is in the range of 10W?100W. The startup time decreases with heating power. Thermal resistances of PHP with filling ratio 20.55% were obviously larger than those with other filling ratios. Thermal resistance of the PHP with R134a is much smaller than that with R404A and R600a. It indicates that the heat transfer ability of R134a is better. In addition, a correlation to predict thermal resistance of PHP with refrigerants was suggested.

  2. Experimental research on the local resistance characteristics of branch pipe in dense phase pneumatic conveying desulfurized gypsum

    NASA Astrophysics Data System (ADS)

    Liu, Zong Ming; Pan, Hong Li; Duan, Guang Bin; Wang, Yong

    2014-04-01

    Pneumatic conveying experiment was carried out in branch pipe branch whose angle would change. In the paper, compressed air was conveying power while dry desulfurized gypsum was conveying materials. The trend of local resistance whose gas-solid flow come through branches with different geometric structure was investigated with different gas-solid flow velocity and solids loading ratio. The result showed that the local resistance loss of branch pipe would increase with the increment of the angle between the branch pipe and the main pipe, the ratio of solid-gas in the pipe and the superficial gas velocity.

  3. Heat transfer from a fully-developed pulsating flow in a curved pipe

    NASA Astrophysics Data System (ADS)

    Chung, Jae Hwa; Hyun, Jae Min

    1994-01-01

    Numerical studies are made of the flow and heat transfer characteristics of a fully-developed pulsating flow in a strongly curved pipe. Emphasis is placed on delineating the effects of the Reynolds number, and pulsation amplitude and frequency. By using a toroidal coordinate system, the complete, time-dependent incompressible Navier-Stokes equations are formulated. The peripherally-uniform temperature condition is imposed on the pipe wall. Particular attention is given to heat transfer properties over substantially extended parameter ranges of the Reynolds number Re and the Womersley number Wo. Use is made of a well-established numerical solution procedure, with minor amendments. The computed results on the flow field are in close agreement with the existing data in the overlapping parameter ranges. The spatial distributions of axial and secondary flows are depicted. The time variations of flow structure are displayed. The numerical results on the spatial and temporal variations of the thermal field are presented. The circumferential profiles of local Nusselt number are plotted at selected instants. When Wo is small, the time- and space-averaged Nusselt numbers, bar-Nu(sub w), is lower for a pulsating flow than for a corresponding non-pulsating flow. At moderate and high Wo, however, the difference in bar-Nu(sub w) between a pulsating and a non-pulsating flow is insignificant.

  4. Average Nusselt number correlation in the thermal entrance region of steady and pulsating turbulent pipe flows

    NASA Astrophysics Data System (ADS)

    Gbadebo, S. A.; Said, S. A. M.; Habib, M. A.

    Empirical correlation has been developed for local and average Nusselt numbers in the thermal entrance region of steady and pulsating turbulent air-flows in a pipe. The correlation was based on experimental data obtained from experiment carried out on a pipe heated under uniform heat flux conditions. The rate of flow was periodically varied at frequencies ranging from 1Hz to 13Hz while the average Reynolds number varied from 6400 to 42000.

  5. Dynamic analysis of a vertically deploying/retracting cantilevered pipe conveying fluid

    NASA Astrophysics Data System (ADS)

    Huo, Yinlei; Wang, Zhongmin

    2016-01-01

    Based on Euler-Bernoulli beam theory and Hamilton's principle, the differential equation of a vertical cantilevered pipe conveying fluid is derived when the pipe has deploying or retracting motion. The resulting equation is discretized via the Galerkin method in which the eigenfunctions of a clamped-free Euler-Bernoulli beam are utilized. Then, the dynamic responses and stability are discussed with regard to the deploying or retracting speed, mass ratio, and fluid velocity. Numerical results reveal that the dynamical behavior of the system is mainly affected by the flow velocity, instantaneous length of pipe, gravity, and mass ratio. For the small flow velocity, the fluid and higher mass ratio helps to stabilize the transverse vibration of the cantilevered pipe conveying fluid in both deployment and retraction modes, and the system will lose stability with the further increase of flow velocity. The critical flow velocity is mainly influenced by the instantaneous length of pipe. The additional restoring force due to gravity causes critical flow velocity to be higher for the vertically cantilevered pipe conveying fluid. Therefore, gravity is conducive to the stability the transverse vibration of the system in both deployment and retraction modes.

  6. Effects of Tip Mass on Stability of Rotating Cantilever Pipe Conveying Fluid with Crack

    NASA Astrophysics Data System (ADS)

    Son, In Soo; Yoon, Han Ik; Lee, Sang Pil; Kim, Dong Jin

    In this paper, the dynamic stability of a rotating cantilever pipe conveying fluid with a crack and tip mass is investigated by numerical method. That is, the effects of the rotating the rotating angular velocity, the mass ratio, the crack and tip mass on the critical flow velocity for flutter instability of system are studied. The equations of motion of rotating pipe are derived by using the extended Hamilton's principle. The crack section of pipe is represented by a local flexibility matrix connecting two undamaged pipe segments. The crack is assumed to be in the first mode of fracture and always opened during the vibrations. Finally, the stability maps of the cracked rotating pipe system as a rotating angular velocity and mass ratio β are presented.

  7. Analytical predictions for vibration phase shifts along fluid-conveying pipes due to Coriolis forces and imperfections

    NASA Astrophysics Data System (ADS)

    Thomsen, Jon Juel; Dahl, Jonas

    2010-07-01

    Resonant vibrations of a fluid-conveying pipe are investigated, with special consideration to axial shifts in vibration phase accompanying fluid flow and various imperfections. This is relevant for understanding elastic wave propagation in general, and for the design and trouble-shooting of phase-shift measuring devices such as Coriolis mass flowmeters in particular. Small imperfections related to elastic and dissipative support conditions are specifically addressed, but the suggested approach is readily applicable to other kinds of imperfection, e.g. non-uniform stiffness or mass, non-proportional damping, weak nonlinearity, and flow pulsation. A multiple time scaling perturbation analysis is employed for a simple model of an imperfect fluid-conveying pipe. This leads to simple analytical expressions for the approximate prediction of phase shift, providing direct insight into which imperfections affect phase shift, and in which manner. The analytical predictions are tested against results obtained by pure numerical analysis using a Galerkin expansion, showing very good agreement. For small imperfections the analytical predictions are thus comparable in accuracy to numerical simulation, but provide much more insight. This may aid in creating practically useful hypotheses that hold more generally for real systems of complex geometry, e.g. that asymmetry or non-proportionality in axial distribution of damping will induce phase shifts in a manner similar to that of fluid flow, while the symmetric part of damping as well as non-uniformity in mass or stiffness do not affect phase shift. The validity of such hypotheses can be tested using detailed fluid-structure interaction computer models or laboratory experiments.

  8. Vortex-induced vibrations of pipes conveying fluid in the subcritical and supercritical regimes

    NASA Astrophysics Data System (ADS)

    Dai, H. L.; Wang, L.; Qian, Q.; Ni, Q.

    2013-05-01

    In this paper, the vortex-induced vibrations of a hinged-hinged pipe conveying fluid are examined, by considering the internal fluid velocities ranging from the subcritical to the supercritical regions. The nonlinear coupled equations of motion are discretized by employing a four-mode Galerkin method. Based on numerical simulations, diagrams of the displacement amplitude versus the external fluid reduced velocity are constructed for pipes transporting subcritical and supercritical fluid flows. It is shown that when the internal fluid velocity is in the subcritical region, the pipe is always vibrating periodically around the pre-buckling configuration and that with increasing external fluid reduced velocity the peak amplitude of the pipe increases first and then decreases, with jumping phenomenon between the upper and lower response branches. When the internal fluid velocity is in the supercritical region, however, the pipe displays various dynamical behaviors around the post-buckling configuration such as inverse period-doubling bifurcations, periodic and chaotic motions. Moreover, the bifurcation diagrams for vibration amplitude of the pipe with varying internal fluid velocities are constructed for each of the lowest four modes of the pipe in the lock-in conditions. The results show that there is a significant difference between the vibrations of the pipe around the pre-buckling configuration and those around the post-buckling configuration.

  9. Heat transfer in pulsating laminar flow in a pipe - A constant wall temperature

    NASA Astrophysics Data System (ADS)

    Kita, Y.; Hirose, K.; Hayashi, T.

    1982-02-01

    An analytical model of heat transfer in a pulsating laminar pipe flow with a constant wall temperature is presented. Governing equations for the velocity profile and the wall shear stress are defined and the temperature field is studied for an instantaneous Nusselt number. Cases of steady and unsteady temperature fields are considered, along with the heat flux in the unsteady state, and a ratio for the Nusselt number in the steady state to that in the pulsating flow is obtained. A method for deriving the instantaneous pipe friction factor is demonstrated and the range of the pressure-gradient amplitudes is determined. Finally, conditions are formulated in which the temperature field, including the heat flux, at the wall are equal to that of the steady state.

  10. A steady-state equilibrium configuration in the dynamic analysis of a curved pipe conveying fluid

    NASA Astrophysics Data System (ADS)

    Jung, Duhan; Chung, Jintai

    2006-06-01

    This paper discusses a steady-state equilibrium configuration and a set of linearized equations of motion for the dynamic analysis of a semi-circular fluid-conveying pipe. Through application of the perturbation method to the equations of motion for a semi-circular pipe, new nonlinear equilibrium equations were derived and the equations of motion were linearized around the equilibrium configuration of the pipe. The equilibrium configurations obtained from the derived nonlinear equilibrium equations were compared to configurations from the linear equilibrium equations of other researchers. Additionally, the natural frequencies computed in this study were compared with the frequencies presented in a previous study. It was found that the steady-state equilibrium configuration should be determined using the proposed nonlinear equilibrium equations rather than previous linear equilibrium equations. Furthermore, it was shown that the natural frequencies computed with the proposed equilibrium equations were more accurate than the frequencies of other studies.

  11. Design and Operation of a Cryogenic Nitrogen Pulsating Heat Pipe

    NASA Astrophysics Data System (ADS)

    Diego Fonseca, Luis; Miller, Franklin; Pfotenhauer, John

    2015-12-01

    We report the design, experimental setup and successful test results using an innovative passive cooling system called a “Pulsating Heat Pipe” (PHP) operating at temperatures ranging from 77 K to 80 K and using nitrogen as the working fluid. PHPs, which transfer heat by two phase flow mechanisms through a closed loop tubing have the advantage that no electrical pumps are needed to drive the fluid flow. In addition, PHPs have an advantage over copper straps and thermal conductors since they are lighter in weight, exhibit lower temperature gradients and have higher heat transfer rates. PHPs consist of an evaporator section, thermally anchored to a solid, where heat is received at the saturation temperature where the liquid portion of the two-phase flow evaporates, and a condenser where heat is rejected at the saturation temperature where the vapor is condensed. The condenser section in our experiment has been thermally interfaced to a CT cryocooler from SunPower that has a cooling capacity of 10 W at 77 K. Alternating regions of liquid slugs and small vapor plugs fill the capillary tubing, with the vapor regions contracting in the condenser section and expanding in the evaporator section due to an electric heater that will generate heat loads up to 10 W. This volumetric expansion and contraction provides the oscillatory flow of the fluid throughout the capillary tubing thereby transferring heat from one end to the other. The thermal performance and temperature characteristics of the PHP will be correlated as a function of average condenser temperature, PHP fill liquid ratio, and evaporator heat load. The experimental data show that the heat transfer between the evaporator and condenser sections can produce an effective thermal conductivity up to 35000 W/m-K at a 3.5 W heat load.

  12. Dynamic behavior of continuous cantilevered pipes conveying fluid near critical velocities

    NASA Technical Reports Server (NTRS)

    Rousselet, J.; Herrmann, G.

    1981-01-01

    The plane motion of a cantilevered pipe conveying fluid is examined when the flow velocity is in the neighborhood of that generating flutter. In contrast to previous studies, the flow velocity is not prescribed as a constant, but is determined from the laws of motion. A system of two nonlinear partial differential equations which are coupled through the nonlinear terms is thereby obtained. The solution is found by the use of the Krylov-Bogoliubov averaging method and the results are discussed indicating the effect of nonlinearities.

  13. Dynamics and stability of short fluid-conveying Timoshenko element pipes

    NASA Astrophysics Data System (ADS)

    Pramila, A.; Laukkanen, J.; Liukkonen, S.

    1991-02-01

    Timoshenko beam elements are used in this paper to analyze vibration and stability of fluid conveying pipes. Also very short pipes—slenderness ratio L/i about 12—are studied. The theoretical background is presented and results are compared with results obtained by Paidoussis et al. In undamped cases only a few elements are needed obtain critical velocities which differ less than 1% from the above-mentioned results. Even in damped cases differences are well below 5%, although slightly different damping assumptions are used.

  14. Simulation and optimization of a pulsating heat pipe using artificial neural network and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Jokar, Ali; Godarzi, Ali Abbasi; Saber, Mohammad; Shafii, Mohammad Behshad

    2016-11-01

    In this paper, a novel approach has been presented to simulate and optimize the pulsating heat pipes (PHPs). The used pulsating heat pipe setup was designed and constructed for this study. Due to the lack of a general mathematical model for exact analysis of the PHPs, a method has been applied for simulation and optimization using the natural algorithms. In this way, the simulator consists of a kind of multilayer perceptron neural network, which is trained by experimental results obtained from our PHP setup. The results show that the complex behavior of PHPs can be successfully described by the non-linear structure of this simulator. The input variables of the neural network are input heat flux to evaporator (q″), filling ratio (FR) and inclined angle (IA) and its output is thermal resistance of PHP. Finally, based upon the simulation results and considering the heat pipe's operating constraints, the optimum operating point of the system is obtained by using genetic algorithm (GA). The experimental results show that the optimum FR (38.25 %), input heat flux to evaporator (39.93 W) and IA (55°) that obtained from GA are acceptable.

  15. Simulation and optimization of a pulsating heat pipe using artificial neural network and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Jokar, Ali; Godarzi, Ali Abbasi; Saber, Mohammad; Shafii, Mohammad Behshad

    2016-01-01

    In this paper, a novel approach has been presented to simulate and optimize the pulsating heat pipes (PHPs). The used pulsating heat pipe setup was designed and constructed for this study. Due to the lack of a general mathematical model for exact analysis of the PHPs, a method has been applied for simulation and optimization using the natural algorithms. In this way, the simulator consists of a kind of multilayer perceptron neural network, which is trained by experimental results obtained from our PHP setup. The results show that the complex behavior of PHPs can be successfully described by the non-linear structure of this simulator. The input variables of the neural network are input heat flux to evaporator (q″), filling ratio (FR) and inclined angle (IA) and its output is thermal resistance of PHP. Finally, based upon the simulation results and considering the heat pipe's operating constraints, the optimum operating point of the system is obtained by using genetic algorithm (GA). The experimental results show that the optimum FR (38.25 %), input heat flux to evaporator (39.93 W) and IA (55°) that obtained from GA are acceptable.

  16. The Dynamic Analysis of a Multispan Fluid-Conveying Pipe Subjected to External Load

    NASA Astrophysics Data System (ADS)

    WU, J.-S.; SHIH, P.-Y.

    2001-01-01

    Instead of the “functional” mode shapes (defined by the admissible, comparison or eigen-functions) employed by the classical assumed mode (or modal analysis) method, the lowest several “numerical” (or vector) mode shapes and the associated natural frequencies of a “non-periodic” multispan pipe with the prescribed supporting conditions and filled with the “stationary” fluid (with velocity U=0) are determined by means of the transfer matrix method (TMM). Using the last mode shapes together with the natural frequencies and incorporating with the expansion theorem, the partial differential equation of motion for the infinite degree-of-freedom (d.o.f.) continuous multispan pipe filled with “flowing” fluid (with U≠0) is converted into a matrix equation. Solving the last matrix equation with the direct integration method gives the dynamic responses of the fluid-conveying pipe. Since the order of the transfer matrix for either each pipe segment or the entire piping system is 4×4, which is independent of the number of the spans for the system, the presented approach is simpler than the existing techniques, particularly for the piping systems with large number of spans. It is also noted that the classical assumed mode (or modal analysis) method is easily applicable only to the special cases where the functions for the approximate mode shapes are obtainable, such as the “single-span” beams or the “periodical” multispan beams (with identical spans and identical constraints). However, the presented “numerical” (or vector) mode method is suitable for many practical engineering problems.

  17. Thermal performance of an open loop closed end pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Saha, Manabendra; Feroz, C. M.; Ahmed, F.; Mujib, T.

    2012-02-01

    This paper presents an experimental study of an open loop pulsating heat pipe (OLPHP) of 0.9 mm inner diameter. The performance characterization has been done using four working fluids at vertical and horizontal orientations. Water, Methanol, 2-Propanol and Acetone has been employed as the working fluid with 50% fill ratio. The experimental results indicate a strong influence of gravity and thermo physical properties of the working fluids on the performance of OLPHP. Considering all the working fluids used, Water has shown better thermal performance in vertical orientation while Methanol has shown better performance in horizontal orientation. All the working fluids perform better at horizontal orientation.

  18. Study on transient local entropy generation in pulsating fully developed laminar flow through an externally heated pipe

    NASA Astrophysics Data System (ADS)

    Yapıcı, Hüseyin; Kayataş, Nesrin; Baştürk, Gamze; Kahraman, Nafiz

    2006-11-01

    This study presents the investigation of transient local entropy generation rate in pulsating fully developed laminar flow through an externally heated pipe. The flow inlet to the pipe is considered as pulsating at a constant period and amplitude (only the velocity oscillates). The simulations are extended to include different pulsating flow cases (sinusoidal flow, step flow, and saw-down flow). To determine the effects of the mean velocity, the period and the amplitude of the pulsating flow on the entropy generation rate, the pulsating flow is examined for various cases of these parameters. Two-dimensional flow and temperature fields are computed numerically with the help of the fluent computational fluid dynamics (CFD) code. In addition to this CFD code, a computer program has been developed to calculate numerically the entropy generation and other thermodynamic parameters by using the results of the calculations performed for the flow and temperature fields. In all investigated cases, the irreversibility due to the heat transfer dominates. The step flow constitutes the highest temperature (about 919 K) and generates the highest total entropy rate (about 0.033 W/K) within the pipe. The results of this study indicate that in the considered situations, the inverse of square of temperature (1/ T 2) is more dominant on the entropy generation than the temperature gradients, and that the increase of the mean velocity of the pulsating flow has an adverse effect on the ratio of the useful energy transfer rate to irreversibility rate.

  19. Theoretical research of helium pulsating heat pipe under steady state conditions

    NASA Astrophysics Data System (ADS)

    Xu, D.; Liu, H. M.; Li, L. F.; Huang, R. J.; Wang, W.

    2015-12-01

    As a new-type heat pipe, pulsating heat pipe (PHP) has several outstanding features, such as great heat transport ability, strong adjustability, small size and simple construction. PHP is a complex two-phase flow system associated with many physical subjects and parameters, which utilizes the pressure and temperature changes in volume expansion and contraction during phase changes to excite the pulsation motion of liquid plugs and vapor bubbles in the capillary tube between the evaporator and the condenser. At present time, some experimental investigation of helium PHP have been done. However, theoretical research of helium PHP is rare. In this paper, the physical and mathematical models of operating mechanism for helium PHP under steady state are established based on the conservation of mass, momentum, and energy. Several important parameters are correlated and solved, including the liquid filling ratio, flow velocity, heat power, temperature, etc. Based on the results, the operational driving force and flow resistances of helium PHP are analysed, and the flow and heat transfer is further studied.

  20. Pulsating Heat pipe Only for Space (PHOS): results of the REXUS 18 sounding rocket campaign

    NASA Astrophysics Data System (ADS)

    Creatini, F.; Guidi, G. M.; Belfi, F.; Cicero, G.; Fioriti, D.; Di Prizio, D.; Piacquadio, S.; Becatti, G.; Orlandini, G.; Frigerio, A.; Fontanesi, S.; Nannipieri, P.; Rognini, M.; Morganti, N.; Filippeschi, S.; Di Marco, P.; Fanucci, L.; Baronti, F.; Mameli, M.; Manzoni, M.; Marengo, M.

    2015-11-01

    Two Closed Loop Pulsating Heat Pipes (CLPHPs) are tested on board REXUS 18 sounding rocket in order to obtain data over a relatively long microgravity period (approximately 90 s). The CLPHPs are partially filled with FC-72 and have, respectively, an inner tube diameter larger (3 mm) and slightly smaller (1.6 mm) than the critical diameter evaluated in static Earth gravity conditions. On ground, the small diameter CLPHP effectively works as a Pulsating Heat Pipe (PHP): the characteristic slug and plug flow pattern forms inside the tube and the heat exchange is triggered by thermally driven self-sustained oscillations of the working fluid. On the other hand, the large diameter CLPHP works as a two- phase thermosyphon in vertical position and doesn't work in horizontal position: in this particular condition, the working fluid stratifies within the device as the surface tension force is no longer able to balance buoyancy. Then, the idea to test the CLPHPs in reduced gravity conditions: as the gravity reduces the buoyancy forces becomes less intense and it is possible to recreate the typical PHP flow pattern also for larger inner tube diameters. This allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience low gravity conditions due to a failure in the yoyo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described.

  1. PHOS Experiment: Thermal Response of a Large Diameter Pulsating Heat Pipe on Board REXUS-18 Rocket

    NASA Astrophysics Data System (ADS)

    Creatini, F.; Guidi, G. M.; Belfi, F.; Cicero, G.; Fioriti, D.; Di Prizio, D.; Piacquadio, S.; Becatti, G.; Orlandini, G.; Frigerio, A.; Fontanesi, S.; Nannipieri, P.; Rognini, M.; Morganti, N.; Filippeschi, S.; Di Marco, P.; Fanucci, L.; Baronti, F.; Mameli, M.; Marengo, M.; Manzoni, M.

    2015-09-01

    In the present work, the results of two Closed Loop Pulsating Heat Pipes (CLPHPs) tested on board REXUS-1 8 sounding rocket in order to get experimental data over a relatively broad reduced gravity period (about 90 s) are thoroughly discussed. The CLPHPs are partially filled with refrigerant FC-72 and have, respectively, an inner tube diameter larger (3 .0 mm) and slightly smaller (1 .6 mm) than a critical diameter defined on Earth gravity conditions. On ground, the small diameter CLPHP works as a real Pulsating Heat Pipe (PHP): the typical capillary slug flow pattern forms inside the device and the heat exchange is triggered by self-sustained thermally driven oscillations of the working fluid. Conversely, the large diameter CLPHP behaves like a two-phase thermosyphon in vertical position while does not operate in horizontal position as the working fluid stratifies within the tube and surface tension is not able to balance buoyancy. Then, the idea to test the CLPHPs under reduced gravity conditions: as soon as gravity reduces, buoyancy becomes less intense and the typical capillary slug flow pattern can also forms within a tube with a larger diameter. Moreover, this allows to increase the heat transfer rate and, consequently, to decrease the overall thermal resistance. Even though it was not possible to experience the expected reduced gravity conditions due to a failure of the yo-yo de-spin system, the thermal response to the peculiar acceleration field (hyper-gravity) experienced on board are thoroughly described.

  2. The dynamic behavior of articulated pipes conveying fluid with periodic flow rate.

    NASA Technical Reports Server (NTRS)

    Bohn, M. P.; Herrmann, G.

    1973-01-01

    The plane motion of two rigid, straight articulated pipes conveying fluid is examined. In contrast to previous work, the flow rate is not taken as constant, but is allowed to have small periodic oscillations about a mean value, as would be expected in a pump-driven system. It is shown that in the presence of such disturbances, both parametric and combination resonances are possible. When the system can also admit loss of stability by static buckling or by flutter, it is found that the presence of small periodic disturbances constitutes a destabilizing effect. Floquet theory and converging infinite determinant expansions are used to illustrate a basic difference between systems which lose stability by divergence and those that lose stability by flutter. An algebraic criterion is obtained for the minimum amplitude of flow-rate oscillation required for the system to be affected by the presence of small disturbances.

  3. Development and test of a cryogenic pulsating heat pipe and a pre-cooling system

    NASA Astrophysics Data System (ADS)

    Bonnet, Fabien; Gully, Philippe; Nikolayev, Vadim

    2012-06-01

    The needs of thermal links in cryogenic applications are increasing, especially because of the use of cryocoolers which offer a reduced size cold finger. The Pulsating Heat Pipe (PHP) is a passive two-phase high performance thermal link. Like the conventional heat pipe, it features a closed tube filled with a two-phase fluid able to transfer heat from its hot part (evaporator) to the cold part (condenser). A general problem for any two-phase cryogenic thermal link is the pre-cooling of the evaporator to ensure the presence of liquid inside the evaporator to start the flow motion. In conventional heat pipes, this problem is by passed by the wick but in the case of PHPs it has to be specially addressed. We have designed, manufactured and tested a helium PHP associated to a novel pre-cooling system. The cool down time of the PHP evaporator is reduced significantly. The maximum transferred power of the PHP is 145 mW with a cold source at 4.2 K.

  4. The effect of pressure pulsations and vibrations on fully developed pipe flow

    NASA Astrophysics Data System (ADS)

    Barnett, D. O.

    1981-08-01

    An analysis is presented of the effect of longitudinal pressure pulsations or vibrations on the velocity distribution in laminar or turbulent fully developed pipe flow. Specifically, the Reynolds equations are formulated in a noninertial reference frame so that the influence of pressure pulsations, vibrations, or a combined pressure and vibrational oscillation can be obtained from a single solution. For axisymmetric developed flow of a constant property (incompressible) fluid, the radial and circumferential momentum equations can be solved and the axial momentum equation is linearized so that the velocity field can be obtained as the sum of a steady and a time-dependent component. By obtaining a solution for the case where the pressure (or amplitude of vibration) varies sinusoidally, one obtains the solution for disturbances of arbitrary waveform through a Fourier series expansion of the disturbance. Results are presented that show that the velocity field is dependent upon the mean flow Reynolds number, a vibrational Reynolds number, and the amplitude of the forcing function. In general, the fluid response to differing waveforms is similar to that obtained for simple harmonic oscillations with respect to the various parameters explored.

  5. Ability of newly emerged adult Culex quinquefasciatus (Diptera: Culicidae) mosquitoes to exit belowground stormwater treatment systems via lateral conveyance pipes.

    PubMed

    Metzger, Marco E; Harbison, Justin E; Burns, Joseph E; Hu, Renjie

    2012-03-01

    Culex quinquefasciatus Say mosquitoes flourish in belowground stormwater systems in the southern United States. Recent evidence suggests that oviposition-site-seeking females may have difficulties locating, entering, and ovipositing inside permanent water chambers when surface entry through pickholes in manhole covers are sealed. It remains unknown, however, if newly emerged adults are able to detect cues necessary to exit these partly sealed systems via lateral conveyance pipes or if they perish belowground. Fourth instar Cx. quinquefasciatus were placed within proprietary belowground stormwater treatment systems to determine the percentage of newly emerged adults able to escape treatment chambers via a single lateral conveyance pipe. Overall, 56% of deployed mosquitoes were captured in adult exit traps with an 1:1 male:female ratio. The percentage of adults captured varied significantly among chambers, but was not associated with structural site characteristics such as the chamber depth or the length and course of conveyance pipe to the exit trap. Empirical observations suggested that longbodied cellar spiders, Pholcus phalangioides (Fuesslin), ubiquitous in these structures, may have reduced adult trap capture. Findings demonstrate that newly emerged Cx. quinquefasciatus can exit subterranean chambers under potentially difficult structural conditions but suggest that a portion may perish in the absence of surface exit points in manhole shafts.

  6. An experimental investigation on heat transfer performance of nanofluid pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Jia, Hongwei; Jia, Li; Tan, Zetao

    2013-10-01

    The effect of SiO2 particles on heat transfer performance of a pulsating heat pipe (PHP) was investigated experimentally. DI water was used as the base fluid and contrast medium for the PHP. In order to study and measure the character, there are SiO2/H2O nanofluids with different concentration and applying with various heating powers during the experiment investigation. According to the experimental result, the high fraction of SiO2/H2O will deteriorate the performance of PHP compared with DI water, i.e. the thermal resistance and the temperature of evaporation section increases. It is in contrary in the case of low fraction of SiO2/H2O. Finally, the comparison of the thermal performances between the normal operation system and the static settlement system is given. It is found that both the thermal resistance of nanofluid PHP and the temperature of the evaporation section increase after standing for a period, and it is the same trend for the temperature fluctuation at the identical heating power for PHP.

  7. Start-up and steady thermal oscillation of a pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Xu, J. L.; Zhang, X. M.

    2005-06-01

    As a novel electronic cooling device, pulsating heat pipes (PHPs) have been received attention in recent years. However, literature survey shows that no studies were carried out on the start-up and steady thermal oscillation of the PHPs. In the present paper, the copper capillary tube was being bended to form the snake-shaped PHP. Heating power was applied on the heating section, and transferred to the condensation section and dissipated to the environment by the pure natural convection. The inside diameter of the capillary tube is 2.0 mm and the working fluid is selected as FC-72. A high speed data acquisition system was used to detect the start-up and steady thermal oscillation of the PHP. Two types of the start-up process were observed: a sensible heat receiving start-up process accompanying an apparent temperature overshoot followed by the steady thermal oscillation at low heating power, and a smooth sensible heat receiving start-up process incorporating a smooth oscillation period at high heating power. For the steady thermal oscillation, also two types were found: the random thermal oscillation with a wide frequency range, indicating the random distribution of the vapor plug and liquid slug inside the capillary tube at low heating power, and the quasi periodic thermal oscillation with the same characteristic frequency for both heating section and condensation section, indicating the uniform distribution of the vapor plug and liquid slug inside the capillary tube at high heating power. The power spectral density (PSD) was used to analyze the thermal oscillation waves. The frequency corresponds to the time that a couple of adjacent vapor plug and liquid slug passing through a specific wall surface.

  8. Understanding thermo-fluidic characteristics of a glass tube closed loop pulsating heat pipe: flow patterns and fluid oscillations

    NASA Astrophysics Data System (ADS)

    Karthikeyan, V. K.; Ramachandran, K.; Pillai, B. C.; Brusly Solomon, A.

    2015-12-01

    An experimental program has been carried out to understand the thermo-fluidic characterization of deionized (DI) water charged closed loop pulsating heat pipe (CLPHP) with flow patterns and fluid oscillations. The CLPHP is examined under vertical and horizontal heating modes with varying heat power. The flow patterns along with fluid oscillations are correlated with thermal performance of the CLPHP. Further, the CLPHP with copper oxide nanofluid study is carried out to understand operational behavior of the device. Fast Fourier frequencies, average frequency of the internal fluid temperature are investigated. Several important features of CLPHP operation are identified by the visual study.

  9. Evaluation of environmental impacts of two common restoration methodologies for pipes that convey stormwater runoff.

    PubMed

    Ren, Dianjun E; Smith, James A

    2012-09-01

    This study investigated the environmental impact of two commercial stormwater pipe-repair technologies (Ultraliner and Troliner). These technologies use liners believed to contain three plasticizers of potential environmental concern: bisphenol A (BPA), di-(2-ethylhexyl) phthalate (DEHP), and benzyl butyl phthalate (BBP). The release of these two products was investigated both experimentally and mathematically. Kinetic batch experiments were conducted to determine if contaminants were leaching from Ultraliner, Troliner, and the grout (used with Troliner) into water. In all cases for all incubation times up to 48 h, none of the three plasticizers were detected in water in contact with any of the pipe-repair materials. A generic GC-FID scan did not detect any unidentified compounds relative to control samples. In addition, a mathematical model of plasticizer leaching from the pipe-liner material was developed. Under various pipe geometries, simulated aqueous concentrations of the plasticizers were less than regulatory limits.

  10. The impact of boundary conditions and fluid velocity on damping for a fluid conveying pipe in a viscous fluid

    NASA Astrophysics Data System (ADS)

    Kjolsing, Eric; Todd, Michael

    2016-04-01

    The hydrocarbon industry has expressed interest in developing vibration based energy harvesting systems that can be deployed downhole and supplement or replace existing power sources. The energy output of such harvesters is highly dependent on the level of damping in the supporting structure which, in this case, would drive the systems vibrational input. A first step towards optimizing an energy harvester configuration is then to understand how key variables influence system damping. To this end an investigation was undertaken to identify how changing system boundary conditions effect damping in a fluid conveying pipe confined by a viscous fluid (i.e. a producing hydrocarbon well). The key variables investigated included the rotational boundary springs, the velocity of the conveyed fluid, and the viscosity of the annulus fluid. The system was modeled using Euler-Bernoulli beam theory and included a hydrodynamic forcing function to capture the effects of the viscous annulus fluid. The natural frequencies of the system were solved in the frequency domain with the system damping subsequently calculated. Lower damping ratios were observed: in stiffer systems, for lower conveyed fluid velocities, and for lower annulus fluid viscosities. A numeric example is provided to illustrate the interaction between the three variables of interest. These results are of direct interest to researchers and engineers developing vibrational energy harvesting systems for downhole deployment. Approved for publication, LAUR-16-21227.

  11. An experimental study on the performance of closed loop pulsating heat pipe (CLPHP) with methanol as a working fluid

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Lutfor; Nourin, Farah Nazifa; Salsabil, Zaimaa; Yasmin, Nusrat; Ali, Mohammad

    2016-07-01

    Thermal control is an important topic for thermal management of small electrical and electronic devices. Closed loop pulsating heat pipe (CLPHP) arises as the best solution for thermal control. The aim of this experimental study is to search a CLPHP of better thermal performance for cooling different electrical and electronic devices. In this experiment, methanol is used as working fluid. The effect of using methanol as a working fluid is studied on thermal performance in different filling ratios and angles of inclination. A copper capillary tube is used where the inner diameter is 2mm,outer diameter is 2.5mm and 250mm long. The CLPHP has 8 loops where the evaporation section is 50mm, adiabatic section is 120mm and condensation section is 80mm. The experiment is done using FR of 40%-70% with 10% of interval and angles of inclination 0° (vertical), 30°, 45°, 60° varying heat input. The results are compared on the basis of evaporator temperature, condenser temperature and their differences, thermal resistance, heat transfer co-efficient, power input and pulsating time. The results demonstrate the effect of methanol in different filling ratios and angles of inclination. M ethanol shows better performance at 30° inclination with 40% FR.

  12. Effect of working fluids on thermal performance of closed loop pulsating heat pipe

    NASA Astrophysics Data System (ADS)

    Kolková, Zuzana; Malcho, Milan

    2014-08-01

    Improving the performance of electrical components needs higher heat removal from these systems. One of the solutions available is to use a sealed heat pipe with a throbbing filling, where development meets the current requirements for intensification of heat removal and elimination of moving parts cooling systems. Heat pipes operate using phase change working fluid, and it is evaporation and condensation. They have a meandering shape and are characterized by high intensity of heat transfer, high durability and reliability. Advantage of these tubes is that it is not necessary to create the internal capillary structure for transporting liquid and they need any pump to the working fluid circulation. They have a simple structure, low cost, high performance, and they can be used for various structural applications. The choice of working fluid volume and performance affects thermal performance. Distilled water, ethanol and acetone were used in the performance ranges 0-80%.

  13. Effect of filling ratio and orientation on the thermal performance of closed loop pulsating heat pipe using ethanol

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Lutfor; Chowdhury, Mehrin; Islam, Nawshad Arslan; Mufti, Sayed Muhammad; Ali, Mohammad

    2016-07-01

    Pulsating heat pipe (PHP) is a new, promising yet ambiguous technology for effective heat transfer of microelectronic devices where heat is carried by the vapor plugs and liquid slugs of the working fluid. The aim of this research paper is to better understand the operation of PHP through experimental investigations and obtain comparative results for different parameters. A series of experiments are conducted on a closed loop PHP (CLPHP) with 8 loops made of copper capillary tube of 2 mm inner diameter. Ethanol is taken as the working fluid. The operating characteristics are studied for the variation of heat input, filling ratio (FR) and orientation. The filling ratios are 40%, 50%, 60% and 70% based on its total volume. The orientations are 0° (vertical), 30°, 45° and 60°. The results clearly demonstrate the effect of filling ratio and inclination angle on the performance, operational stability and heat transfer capability of ethanol as working fluid of CLPHP. Important insight of the operational characteristics of CLPHP is obtained and optimum performance of CLPHP using ethanol is thus identified. Ethanol works best at 50-60%FR at wide range of heat inputs. At very low heat inputs, 40%FR can be used for attaining a good performance. Filling ratio below 40%FR is not suitable for using in CLPHP as it gives a low performance. The optimum performance of the device can be obtained at vertical position.

  14. Effect of using acetone and distilled water on the performance of open loop pulsating heat pipe (OLPHP) with different filling ratios

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Lutfor; Afrose, Tonima; Tahmina, Halima Khatun; Rinky, Rumana Parvin; Ali, Mohammad

    2016-07-01

    Pulsating heat pipe (PHP) is a new innovation in the modern era of miniaturizes thermal management system for its higher heating and cooling capacity. The objective of this experiment is to observe the performance of open loop pulsating heat pipe using two fluids at different filling ratios. This OLPHP is a copper capillary tube of 2.5mm outer diameter and 2mm inner diameter. It consists of 8 loops where the evaporative section is 50mm, adiabatic section is 120mm and condensation section is 80mm. The experiment is conducted with distilled water and acetone at 40%, 50%, 60%, and 70% filling ratios where 0° (vertical) is considered as definite angle of inclination. Distilled water and acetone are selected as working fluids considering their different latent heat of vaporization and surface tension. It is found that acetone shows lower thermal resistance than water at all heat inputs. Best performance of acetone is attained at 70% filling ratio. Water displays better heat transfer capability at 50% filling ratio.

  15. Experimental investigation on thermal performance of a closed loop pulsating heat pipe (CLPHP) using methanol and distilled water at different filling ratios

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Lutfor; Swarna, Anindita Dhar; Ahmed, Syed Nasif Uddin; Perven, Sanjida; Ali, Mohammad

    2016-07-01

    Pulsating Heat Pipes, the new two-phase heat transfer devices, with no counter current flow between liquid and vapor have become a modern topic for research in the field of thermal management. This paper focuses on the performance of methanol and distilled water as working fluid in a closed loop pulsating heat pipe (CLPHP). This performances are compared in terms of thermal resistance, heat transfer co-efficient, and evaporator and condenser wall temperature with variable heat inputs. Methanol and Distilled water are selected for their lower surface tension, dynamic viscosity and sensible heat. A closed loop PHP made of copper with 2mm ID and 2.5mm OD having total 8 loops are supplied with power input varied from 10W to 60W. During the experiment the PHP is kept vertical, while the filling ratio (FR) is increased gradually from 40% to 70% with 10% increment. The optimum filling ratio for a minimum thermal resistance is found to be 60% and 40% for distilled water and methanol respectively and methanol is found to be the better working fluid compared to distilled water in terms of its lower thermal resistance and higher heat transfer coefficient.

  16. Effect of using ethanol and methanol on thermal performance of a closed loop pulsating heat pipe (CLPHP) with different filling ratios

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Lutfor; Salsabil, Zaimaa; Yasmin, Nusrat; Nourin, Farah Nazifa; Ali, Mohammad

    2016-07-01

    This paper presents an experimental study of a closed loop Pulsating Heat Pipe (CLPHP) as the demand of smaller and effective heat transfer devices is increasing day by day. PHP is a two phase heat transfer device suited for heat transfer applications, especially suited for handling moderate to high heat fluxes in different applications. A copper made Pulsating Heat Pipe (PHP) of 250 mm length is used in this experimental work with 2 mm ID and 3 mm OD, closed end-to-end in 8 looped, evacuated and then partially filled with working fluids. The evaporation section is 50 mm, adiabatic section is 120 mm and condensation section is 80 mm. The performance characterization is done for two working fluids at Vertical (0°) orientations. The working fluids are Methanol and Ethanol and the filling ratios are 40%, 50%, 60% & 70% based on total volume, respectively. The results show that the influence of various parameters, the heat input flux, and different filling ratios on a heat transfer performance of CLPHP. Methanol shows better performance as working fluid in PHP than ethanol at present orientation for a wide range of heat inputs and can be used at high heat input conditions. Ethanol is better choice to be used in low heat input conditions.

  17. Pulsating Stars

    NASA Astrophysics Data System (ADS)

    Catelan, M.; Smith, H. A.

    2015-03-01

    This book surveys our understanding of stars which change in brightness because they pulsate. Pulsating variable stars are keys to distance scales inside and beyond the Milky Way galaxy. They test our understanding not only of stellar pulsation theory but also of stellar structure and evolution theory. Moreover, pulsating stars are important probes of the formation and evolution of our own and neighboring galaxies. Our understanding of pulsating stars has greatly increased in recent years as large-scale surveys of pulsating stars in the Milky Way and other Local Group galaxies have provided a wealth of new observations and as space-based instruments have studied particular pulsating stars in unprecedented detail.

  18. Electrodynamic pulsator

    SciTech Connect

    Myslinski, A.; Semeniuk, B.; Kasprzycka-Guttman, T. . Dept. of Chemistry)

    1993-11-01

    An electrodynamic pulsator, designed for the reciprocation of liquids in an pulsed extractor, is described. Application of the pulsator is illustrated by its performance in connection with a laboratory packed column used for extraction of citric acid from aqueous solutions by cyclohexanone. A schematic of the pulsator is shown. This pulsator was designed to avoid the indirect, stepwise, mechanical regulation systems used in pulsed extractors which employ an external device such as a piston pump.

  19. Erosion resistant elbow for solids conveyance

    DOEpatents

    Not Available

    An elvow and process for fabrication for use in particulate material conveying comprising a curved outer pipe, a curved inner pipe having the same radius of curvature as the outer pipe, concentric with and internal to the outer pipe, comprising an outer layer comprised of a first material and an inner layer comprised of a second material wherein said first material is characterized by high erosion resistance when impinged by particulate material and wherein said second material is characterized by high tensile strength and flexibility, and an inner pipe supporting means for providing support to said inner pipe, disposed between said inner pipe and said outer pipe. 4 figures.

  20. Analysis of pressure drop characteristics and methods for calculating gas and gas-solid flow in horizontal pipes for dilute coal conveying system

    SciTech Connect

    Weiguo Pan; Zuohe Chi; Yongjing Liao

    1997-07-01

    This article reported pressure drop characteristics and methods for calculating friction factors {lambda} 0 and {lambda}{sub {mu}} for gas and gas-solids flows, respectively, in straight horizontal pipes are summarized advantages seed. The and disadvantages of calculating friction factor {lambda}{sub {mu}} through dimensional analysis in comparison with model simulation are analyzed. It is pointed out that model simulation is more suitable to engineering use than dimensional analysis. According to experimental results of dilute gas-coal powder flow in straight horizontal pipes of the coal pulverization system in a power plant; an empirical formula and a theoretical formula for calculating friction factor {lambda}{sub {mu}} in straight horizontal pipes transporting dilute coal powder are obtained.

  1. Some spectral and pulsation characteristics of the horizontal flow of a gas-liquid suspension

    NASA Astrophysics Data System (ADS)

    Krokovnyi, P. M.

    1980-02-01

    In the experiments described, the turbulence characteristics of a two-phase gas-liquid pipe flow were studied, using a 6 m long, 19-mm-diam tube. The inlet temperature of the suspension was maintained at 25 C. The friction energy spectra and the relative intensity of the friction pulsations were measured. The spectral and pulsation characteristics were obtained by an electrodiffusion technique which provided reliable data on the pulsations of the wall shear stress.

  2. Some spectral and pulsation characteristics of a horizontal gas-liquid stream

    NASA Astrophysics Data System (ADS)

    Krokovnyi, P. M.

    1980-07-01

    In the experiments described, the turbulence characteristics of a two-phase gas-liquid pipe flow were studied, using a 6 m long, 19-mm-diam tube. The inlet temperature of the suspension was maintained at 25 C. The friction energy spectra and the relative intensity of the friction pulsations were measured. The spectral and pulsation characteristics were obtained by an electrodiffusion technique which provided reliable data on the pulsations of the wall shear stress.

  3. On conveying and not conveying expertise.

    PubMed

    Rappert, Brian; Coopmans, Catelijne

    2015-08-01

    This article attends to the movement between disclosing and non-disclosing in accounts of expertise. While referencing discussions about tacit knowledge ('experts know more than they can say') and the politics of non-disclosure ('withholding can help as well as harm the credibility of experts'), in the main it considers how experts move between conveying and not conveying in order to make their proficiencies recognized and accessible to others. The article examines this movement through a form that partakes in it, thus drawing attention to conventions and tensions in how authors make themselves accountable, and their subject matter available, to audiences. It thereby proposes to explore the possibilities of careful, and generative, non-disclosure as part of expert writing practices. PMID:26502661

  4. A study of the pulsation driving mechanism in pulsating combustors

    NASA Astrophysics Data System (ADS)

    Goldman, Y.; Timnat, Y. M.

    Experiments performed in a facility consisting of a Schmidt-type pulsating combustor, in which high-speed photographs were taken and pressure, temperature and gas composition measured, showed that the air supply conditions at the inlet and the volume of the combustor strongly influence the oscillation frequency. From the measurements, the existence of two separate regions, one containing cold air and the other containing fuel-rich gas, was found, and a pressure-volume diagram was drawn, showing the effect of chemical energy release and heat supply during the compression stroke and differentiating it from the expansion. A model of the interaction between the cyclic combustion process and the acoustic oscillations of the gas volume within the chamber and the tail-pipe is presented. The conditions for chemical energy release that result in high-pressure amplitude are described.

  5. Investigations of Pressure Drops during Piston Flow Pneumatic Conveying of Ice Cubes and Applying It to High Density Conveying of Cold Energy

    NASA Astrophysics Data System (ADS)

    Ohira, Akiyoshi; Yanadori, Michio; Tsubota, Yuji

    To overcome the defect of conventional chilled water systems, we propose pneumatic conveying of ice cubes. We conducted experiments to investigate the pressure drops during pneumatic conveying of ice cubes in a prototype conveyance pipe, and obtained the following results : (1)The mean velocity of the ice cubes is proportional to the mean velocity of the conveying air flow regardless of balls in the pipe or the volume fraction of the ice cubes. (2) Difference in the velocity of the air flow cause variations in the density of ice cubes. If we convey ice cubes with balls, it is possible to convey a higher density. (3) The volume fraction of this method is about 10 times that of the previous experimental results. (4)The pump power of this proposed conveyance system is reduced to about 0.71 to 0.59 times that of the conventional chilled water systems.

  6. Optimizing pneumatic conveying of biomass materials

    NASA Astrophysics Data System (ADS)

    DiCianni, Matthew Edward Michael

    2011-12-01

    Biomass is a readily available but underutilized energy resource. One of the main challenges is the inability of biomass feed stocks like corn stover or wood chips to flow freely without intermittent jamming. This research integrated an automated pneumatic conveying system to efficiently transport biomass into a biomass reactor. Material was held in a storage container until an end effector attached to a 3-axis controller engaged the material to flow through pneumatic vacuum in the carrier fluid of air. The material was disengaged from the carrier fluid through centripetal forces induced by a cyclone separator. As the air was pulled out of the cyclone, the biomass drops out the bottom due to gravitational forces and fell into a secondary storage hopper. The second storage container was for testing purposes only, where the actual apparatus would use a vertically oriented lock hopper to feed material into the biomass reactor. In the experimental test apparatus, sensors measured the storage hopper weight (mass-flow rate), pressure drop from the blower, and input power consumption of the motor. Parameters that were adjusted during testing include pipe diameter, material type, and motor speed. Testing indicated that decreasing the motor speed below its maximum still allows for conveyance of the material without blockage forming in the piping. The data shows that the power consumption of the system can be reduced based on the size and weight of the material introduced to the conveying pipe. Also, conveying certain materials proved to be problematic with particular duct diameters. Ultimately, an optimal duct diameter that can perform efficiently for a broad range of materials was chosen for the given system. Through these improvements, the energy return on investment will be improved for biomass feed stocks, which is taking a step in the right direction to secure the nation's energy independence.

  7. Characteristics of Pulsating Aurora

    NASA Astrophysics Data System (ADS)

    Humberset, B. K.; Gjerloev, J. W.; Mann, I. R.; Samara, M.; Michell, R.

    2013-12-01

    We have investigated the spatiotemporal characteristics of pulsating auroral patches observed with an all-sky imager located at Poker Flat, Alaska. Pulsating aurora often covers the entire sky with intermixed large and small-scale patches that vary in intensity or disappear and reappear on different time scales and timings. The broad definition of pulsating aurora covers patches and bands from tens to several tens of km which have a quasi-periodic temporal variation from 1 s to tens of seconds. In this paper we examine >15 patches from different events. We analyze all-sky movies (557.7 nm, 3.31 Hz) with a simple, yet robust, technique that allows us to determine the scale size dependent variability of the >15 individual patches. A spatial 2D Fourier Transform is used to separate the aurora into different horizontal scale sizes, and by correlating each patch for all image separations and available scale sizes smaller than the patch itself, we reveal what scale sizes are pulsating and their variability. The patches are found to be persistent, meaning that we can follow them for typically 5 minutes. The period of the pulsations is often remarkably variable and it seems that only certain scale sizes pulsate (typically the size of the patch). The patches drift with the background ExB plasma drift indicating that the magnetospheric source mechanism drifts with the field lines.

  8. Vertical-Screw-Auger Conveyer Feeder

    NASA Technical Reports Server (NTRS)

    Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

    2016-01-01

    A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger. Additional scoops are possible by adding a cylindrical section above the conical funnel section. Such then allows the unit to collect material from swaths larger in diameter than the enclosing casing pipe of the screw auger. A third element includes a flexible screw auger. All three can be used in combination in microgravity and zero atmosphere environments to drill and recover a wide area of subsurface regolith and entrained volatiles through a single access point on the surface.

  9. Le couplage pulsation-convection.

    NASA Astrophysics Data System (ADS)

    Poyet, J.-P.

    Contents: Quelques problèmes Boussinesq bien definis. Les théories de couplage pulsation radiale-convection. Quelques pas dans le domaine du couplage des pulsations non radiales avec la convection. Conclusion.

  10. Stellar Pulsation: an Overview

    NASA Astrophysics Data System (ADS)

    Kurtz, D. W.

    2006-04-01

    Twenty-five hundred years ago the Pythagorean Brotherhood invented the idea of the Music of the Spheres. That idea languished in scientific thought from the time of Kepler 400 years ago, until the 1970s when real sounds were found and recognised in the sun and stars. Stars pulsate both with sound waves in pressure modes and in gravity modes with buoyancy as the restoring force. Those pulsations allow us literally to see inside the stars to know their interiors. Oscillations in 1-D and 2-D are introduced here, leading to 3-D descriptions of the changing shapes of pulsating star. Some properties of pressure modes and gravity modes are explained, and a simple explanation of asteroseismology is given. Some selected cases illustrate amazing discoveries from our new ability to see inside the stars.

  11. Stellar pulsation: an overview

    NASA Astrophysics Data System (ADS)

    Kurtz, D. W.

    2006-01-01

    Twenty-five hundred years ago the Pythagorean Brotherhood invented the idea of the Music of the Spheres. That idea languished in scientific thought from the time of Kepler 400 years ago, until the 1970s when real sounds were found and recognised in the sun and stars. Stars pulsate both with sound waves in pressure modes and in gravity modes with buoyancy as the restoring force. Those pulsations allow us literally to see inside the stars to know their interiors. Oscillations in 1-D and 2-D are introduced here, leading to 3-D descriptions of the changing shapes of pulsating star. Some properties of pressure modes and gravity modes are explained, and a simple explanation of asteroseismology is given. Some selected cases illustrate amazing discoveries from our new ability to see inside the stars.

  12. Dynamic study of piping systems for reciprocating compressors

    SciTech Connect

    Wakabayashi, A.; Arai, S.; Yamada, S.

    1995-12-01

    Recently the authors have developed the direct method to study vibration of piping systems for reciprocating compressors, based on the requirement by API-618 Design Approach-3. They have examined the reliability of this direct method by some experiments with a test piping system, by pressure pulsation and nodal vibration measurements. Overall pressure pulsation amplitude and its frequency components at each measurement point were proved.to agree with the results by digital analysis. Close evaluation of ``pipe-supports` stiffness``, as well as boundary conditions, was confirmed to be a necessary condition to proceed the dynamic analysis of the piping system in relation to the pressure pulsation Generated by the reciprocating compressor, which affected the accuracy of final estimation of nodal displacement distribution of the piping system. Field data evaluation is also discussed in this paper.

  13. Computational astrophysics: Pulsating stars

    NASA Astrophysics Data System (ADS)

    Davis, C. G.

    The field of computational astrophysics in pulsating star studies has grown considerably since the advent of the computer. Initially calculations were done on the IBM 704 with 32K of memory and now we use the CRAY YMP computers with considerably more memory. Our early studies were for models of pulsating stars using a 1D Lagrangian hydrodynamic code (SPEC) with radiation diffusion. The radiative transfer was treated in the equilibrium diffusion approximation and the hydrodynamics was done utilizing the approximation of artificial viscosity. The early calculations took many hours of 704 CPU time. Early in 1965 we decided to improve on the usual treatment of the radiative transfer used in our codes by utilizing the method of moments, the so-called variable Eddington approximation. In this approximation the material energy field is uncoupled from the radiation energy field and the angular dependence is introduced through the Eddington factor. A multigroup frequency dependent method may also be applied. The Eddington factor is determined by snapshots of the stars structure utilizing a y-line approximation. The full radiative transfer approximation appears necessary in order to understand the light curves for W Virginia stars and may be important for the light curves of RR Lyrae stars. A detailed radiative transfer method does not appear to be necessary for the understanding of Cepheid light curves. A recent improvement to our models for pulsating stars is in the use of an adaptive mesh scheme to resolve the sharp features in the nonlinear hydrodynamic structure. From these improved structures, better analysis of the radius, velocity, and light curves could be obtained.

  14. Nonperiodic eddy pulsations

    USGS Publications Warehouse

    Rubin, David M.; McDonald, Richard R.

    1995-01-01

    Recirculating flow in lateral separation eddies is typically weaker than main stem flow and provides an effective environment for trapping sediment. Observations of recirculating flow and sedimentary structures demonstrate that eddies pulsate in size and in flow velocity even when main stem flow is steady. Time series measurements of flow velocity and location of the reattachment point indicate that these pulsations are nonperiodic. Nonperiodic flow in the lee of a channel margin constriction is grossly different from the periodic flow in the lee of a cylinder that is isolated in a flow. Our experiments demonstrate that placing a flow-parallel plate adjacent to a cylinder is sufficient to cause the leeside flow to change from a periodic sequence of vortices to a nonperiodically pulsating lateral separation eddy, even if flow conditions are otherwise unchanged. Two processes cause the leeside flow to become nonperiodic when the plate is added. First, vortices that are shed from the cylinder deform and become irregular as they impact the plate or interfere with remnants of other vortices near the reattachment point. Second, these deformed vortices and other flow structures are recirculated in the lateral separation eddy, thereby influencing the future state (pressure and momentum distribution) of the recirculating flow. The vortex deformation process was confirmed experimentally by documenting spatial differences in leeside flow; vortex shedding that is evident near the separation point is undetectable near the reattachment point. Nonlinear forecasting techniques were used in an attempt to distinguish among several possible kinds of nonperiodic flows. The computational techniques were unable to demonstrate that any of the nonperiodic flows result from low-dimensional nonlinear processes.

  15. OGLE and pulsating stars

    NASA Astrophysics Data System (ADS)

    Udalski, A.

    2016-05-01

    OGLE-IV is currently one of the largest sky variability surveys worldwide, focused on the densest stellar regions of the sky. The survey covers over 3000 square degrees and monitors regularly over a billion sources. The main targets include the inner Galactic bulge and the Magellanic System. Supplementary shallower Galaxy Variability Survey covers the extended Galactic bulge and 2/3 of the whole Galactic disk. The current status, prospects, and the latest results of the OGLE-IV survey focused on pulsating stars, in particular RR Lyrae variables, are presented.

  16. Pulsation driving and convection

    NASA Astrophysics Data System (ADS)

    Antoci, Victoria

    2015-08-01

    Convection in stellar envelopes affects not only the stellar structure, but has a strong impact on different astrophysical processes, such as dynamo-generated magnetic fields, stellar activity and transport of angular momentum. Solar and stellar observations from ground and space have shown that the turbulent convective motion can also drive global oscillations in many type of stars, allowing to study stellar interiors at different evolutionary stages. In this talk I will concentrate on the influence of convection on the driving of stochastic and coherent pulsations across the Hertzsprung-Russell diagram and give an overview of recent studies.

  17. Heat pipes - Thermal diodes

    NASA Astrophysics Data System (ADS)

    Aptekar, B. F.; Baum, J. M.; Ivanovskii, M. N.; Kolgotin, F. F.; Serbin, V. I.

    The performance concept and peculiarities of the new type of thermal diode with the trap and with the wick breakage are dealt with in the report. The experimental data were obtained and analysed for the working fluid mass and the volume of the liquid in the wick on the forward-mode limiting heat transfer. The flow rate pulsation of the working fluid in the wick was observed visually on the setup with the transparent wall. The quantitative difference on the data on the investigated thermal diode and on the identical heat pipes without the wick breakage is found experimentally concerning the forward-mode limiting heat transfer.

  18. Total pressure averaging in pulsating flows

    NASA Technical Reports Server (NTRS)

    Krause, L. N.; Dudzinski, T. J.; Johnson, R. C.

    1972-01-01

    A number of total-pressure tubes were tested in a non-steady flow generator in which the fraction of period that pressure is a maximum is approximately 0.8, thereby simulating turbomachine-type flow conditions. Most of the tubes indicated a pressure which was higher than the true average. Organ-pipe resonance which further increased the indicated pressure was encountered within the tubes at discrete frequencies. There was no obvious combination of tube diameter, length, and/or geometry variation used in the tests which resulted in negligible averaging error. A pneumatic-type probe was found to measure true average pressure, and is suggested as a comparison instrument to determine whether nonlinear averaging effects are serious in unknown pulsation profiles. The experiments were performed at a pressure level of 1 bar, for Mach number up to near 1, and frequencies up to 3 kHz.

  19. 30. DETAIL OF PIPE FEED SYSTEM TO CLASSIFIER, LOOKING EAST. ...

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

    30. DETAIL OF PIPE FEED SYSTEM TO CLASSIFIER, LOOKING EAST. THIS PIPE WAS MOUNTED ALONG THE JOISTS AT TOP, ALIGNING WITH THE TWO SMALLER PIPES PROTRUDING DOWNWARD FROM THE JOISTS. THESE PIPES CONVEYED PULP MATERIAL FROM THE STAMP APRONS ON THE UPPER FLOOR TO THE CLASSIFIER, SEEN IN THE DISTANCE AT CENTER. THE STRUCTURAL SUPPORTS AT CENTER LEFT WREE ADDED AS PART OF THE MILL STABILIZATION BY THE PARK SERVICE IN 1993-4. THIS WOUND AND RIVITED PIPE IS IDENTICAL TO THE 23-MILE PIPELINE THAT CONVEYED WATER TO THE MILL FROM TELESCOPE PEAK. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

  20. An optical method for measuring the thickness of a falling condensate in gravity assisted heat pipe

    NASA Astrophysics Data System (ADS)

    Kasanický, Martin; Lenhard, Richard; Kaduchová, Katarína; Malcho, Milan

    2015-05-01

    A large number of variables is the main problem of designing systems which uses heat pipes, whether it is a traditional - gravity, or advanced - capillary, pulsating, advanced heat pipes. This article is a methodology for measuring the thickness of the falling condensate in gravitational heat pipes, with using the optical triangulation method, and the evaluation of risks associated with this method.

  1. Numerical study of unsteady convective heat transfer in pulsating duct flows

    NASA Astrophysics Data System (ADS)

    Stosic, N.; Hanjalic, K.

    Numerical study results are presented for hydrodynamic parameters and heat transfer in a periodic gas flow, within a circular pipe in which flow oscillations were generated by pressure variation at one of the pipe ends. A comparison of experimental and numerical results has demonstrated satisfactory agreement, as well as the significant augmentation of the heat transfer coefficient under those resonant conditions in which the flow pulsation incitement frequencies correspond to the natural frequencies of the duct.

  2. Characterizing Accreting White Dwarf Pulsators

    NASA Astrophysics Data System (ADS)

    Szkody, Paula; Mukadam, Anjum

    2014-02-01

    Understanding the population, mass distribution, and evolution of accreting white dwarfs impacts the entire realm of binary interaction, including the creation of Type Ia supernovae. We are concentrating on accreting white dwarf pulsators, as the pulsation properties allow us a view of how the accretion affects the interior of the star. Our ground- based photometry on 11 accreting pulsators with corresponding temperatures from HST UV spectra suggest a broad instability strip in the range of 10500 to 16000K. Additionally, tracking a post-outburst heated white dwarf as it cools and crosses the blue edge and resumes pulsation provides an independent method to locate the empirical instability strip. Determining a post-outburst cooling curve yields an estimate of the amount of heating and the accreted mass during the outburst. We request additional photometry of 2 objects that present unique properties: GW Lib which has not yet returned to its pre-outburst pulsation spectrum after 6 yrs, and EQ Lyn which returned to its pre- outburst pulsation after 3 yrs but is now turning on and off without ongoing outbursts. Following the pulsation spectrum changes over stretches of several nights in a row will provide specific knowledge of the stability of the observed modes.

  3. An investigation into pulsating aurora

    NASA Astrophysics Data System (ADS)

    Williams, John Denis

    2002-01-01

    On March 13, 1997 a sounding rocket equipped to study pulsating aurora was launched into the recovery phase of a small magnetic substorm. The launch originated from Poker Flat, Alaska and moved northward, reaching a apogee of 385 km and crossing field lines from L = 5.6 to L = 8. This sounding rocket was the first to have instruments designed to measure the upgoing and downgoing electron precipitation in the region over a pulsating auroral event. Nine pulsations were observed during the course of the 10 minute flight. This dissertation discusses the design, fabrication and calibration of the particle detection instruments, which include solid state telescopes (SST's) and an electrostatic analyzer (ESA). Observations led to an inferred parallel electric field above the rocket, the first time such a field had been associated with pulsating aurora. The data showed that there were no pulsations for electrons with energies less than 5 keV for pitch-angles between 22° and 90° but pulsations were seen for electrons from 5 keV down to 1 keV for field aligned precipitating electrons and for all upgoing electrons. Furthermore, the greatest change between background and pulsation occurred for electrons between 10 and 20 keV with pitch-angles between 50° and 90°. Observations also showed anomolous pitch-angle distributions, with larger than expected fluxes of high energy electrons leaving the ionosphere. Also missing from the data is evidence of either velocity dispersed arrival of electrons or 3 Hz oscillations. The data analysis of the measurements provided many new insights into pulsating aurora and has raised questions about the source of the pulsating mechanism and the mechanism itself. The data are compared to three current theoretical models and we find that they cannot adequately describe the observations. Other models are discussed and also discarded as being unable to explain all of the observations.

  4. Pulsating incinerator hearth

    SciTech Connect

    Basic, J.N. Sr.

    1984-10-09

    A pulsating hearth for an incinerator wherein the hearth is suspended on a fixed frame for movement in a limited short arc to urge random size particles burning in a pile on the hearth in a predetermined path intermittently across the surface of the heart. Movement is imparted to the hearth in periodic pulses preferably by inflating sets of air bags mounted on the frame, which stroke the hearth to move it a short distance from an initial position and jar it against the frame, thus impelling the burning particles a short distance by inertia and concurrently stoking the burning pile upon each stroke, and then returning the hearth to its initial position. The hearth may also have a plurality of nozzles connected to a source of air for delivering gently flowing air to the burning pile on the hearth.

  5. Ground Observations of ULF Pulsations During Pulsating Aurora

    NASA Astrophysics Data System (ADS)

    Kim, H.; Lessard, M.; Jones, S.; Engebretson, M.

    2008-12-01

    The ROPA (Rocket Observations of Pulsating Aurora) sounding rocket was launched northward from Poker Flat, crossing the poleward boundary of a region of pulsating aurora. In association with ground support (incoherent scatter radar, ULF search-coil magnetometer, fluxgate magnetometer, and all sky imager), pulsating auroral signatures have been observed on the ground and in space. During or before the periods of pulsating aurora, the observations of ULF waves revealed two signatures. A narrow band signal, which exhibits an abrupt onset and a rising tone from 0.1 to 0.3 Hz over the course of an hour or two, precedes the pulsating aurora in 4 of 5 events studied but is not observed in the 5th event. Following the narrow band signature, or possibly beginning while the narrow band signal is still observed, broad band waves (characterized by noisy spectral structure) are observed that are strongly modulated (in all of the events) with a period on the order of 10 15 minutes. In this presentation, we discuss the nature of these waves such as polarization (predominantly right handed). Some of the events show double band spectral signatures where the upper ones rise and lower ones fall with periodic spectral signatures (4 - 5 min) and harmonic structures. It is also discussed how they are generated and what role they might play in pulsating aurora.

  6. Organ pipe resonance induced vibration in piping system

    SciTech Connect

    Wang, T.

    1996-12-01

    Acoustic-induced vibration is a fluid-structure interaction phenomenon. The feedback mechanism between the acoustic pressure pulsation and the structure movements determines the excited acoustic modes which, in turn, amplify the structure response when confidence frequency and mode shape matching occurs. The acoustic modes are not determined from the acoustic boundary conditions alone, structure feedback is as responsible for determining the acoustic modes and shaping the resulting forcing functions. Acoustic-induced piping vibration, when excited, does not attenuate much with distance. Pressure pulsation can be transmitted throughout the piping system and its branch connections. It is this property that makes vibration monitoring difficult, because vibration can surface at locations far away from the acoustic source when resonance occurs. For a large piping system with interconnected branches, the monitoring task can be formidable, particularly when there is no indication what the real source is. In organ pipe resonance induced vibration, the initiating acoustic source may be inconspicuous or unavoidable during operation. In these situations, the forcing function approach can offer an optimal tool for vibration assessment. The forcing function approach was used in the evaluation of a standby steam piping vibration problem. Monitoring locations and instrument specifications were determined from the acoustic eigenfunction profiles. Measured data confirmed the presence of coherent vibrations in the large bore piping. The developed forcing function permits design evaluation of the piping system, which leads to remedial actions and enables fatigue life determination, thus providing confidence to system operation. The forcing function approach is shown to be useful in finding potential vibration area and verifying the integrity of weak structure links. Application is to steam lines at BWR plants.

  7. Generation and control of pressure pulsations emitted from centrifugal pumps: A review

    SciTech Connect

    Rzentkowski, G.

    1996-12-01

    Pressure pulsations emitted by centrifugal pumps may strongly interact with a piping system, leading to excessive vibration and alternating stresses beyond endurance limits. Several cases of this nature were reported, especially in chemical, petro-chemical and power generation industries, causing costly repairs and loss of power. In the past, research attention was primary focused on corrective actions involving the design and installation of piping elements to absorb acoustic energy emitted by pumps. Currently, more emphasis is placed on developing analytical tools to predict piping system acoustics and avoid undesirable resonance effects. Little attention has been directed towards preventive actions, leading to a better understanding of pumps as an acoustic source. This paper provides an overview of the underlying excitation mechanisms and modelling techniques, and explores the role of pump design parameters in controlling pressure pulsations. The application here is to primary heat transport system of CANDU reactor.

  8. Underground pipe inspection device and method

    SciTech Connect

    Germata, Daniel Thomas

    2009-02-24

    A method and apparatus for inspecting the walls of an underground pipe from inside the pipe in which an inspection apparatus having a circular planar platform having a plurality of lever arms having one end pivotably attached to one side of the platform, having a pipe inspection device connected to an opposite end, and having a system for pivoting the lever arms is inserted into the underground pipe, with the inspection apparatus oriented with the planar platform disposed perpendicular to the pipe axis. The plurality of lever arms are pivoted toward the inside wall of the pipe, contacting the inside wall with each inspection device as the apparatus is conveyed along a length of the underground pipe.

  9. Pulsating Star Mystery Solved

    NASA Astrophysics Data System (ADS)

    2010-11-01

    By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. Up to now astronomers had two incompatible theoretical predictions of Cepheid masses. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations. The new results, from a team led by Grzegorz Pietrzyński (Universidad de Concepción, Chile, Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Poland), appear in the 25 November 2010 edition of the journal Nature. Grzegorz Pietrzyński introduces this remarkable result: "By using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile, along with other telescopes, we have measured the mass of a Cepheid with an accuracy far greater than any earlier estimates. This new result allows us to immediately see which of the two competing theories predicting the masses of Cepheids is correct." Classical Cepheid Variables, usually called just Cepheids, are unstable stars that are larger and much brighter than the Sun [1]. They expand and contract in a regular way, taking anything from a few days to months to complete the cycle. The time taken to brighten and grow fainter again is longer for stars that are more luminous and shorter for the dimmer ones. This remarkably precise relationship makes the study of Cepheids one of the most effective ways to measure the distances to nearby galaxies and from there to map out the scale of the whole Universe [2]. Unfortunately, despite their importance, Cepheids are not fully understood. Predictions of their masses derived from the theory of pulsating stars are 20-30% less than predictions from the theory of the

  10. Impact of sorption phenomena on multiphase conveying processes

    NASA Astrophysics Data System (ADS)

    Hatesuer, Florian; Groth, Tillmann; Reichwage, Mark; Mewes, Dieter; Luke, Andrea

    2011-08-01

    Twin-screw multiphase pumps are employed increasingly to convey multiphase mixtures of crude oil, accompanying fluids, associated gas and solid particles. They are positive displacement pumps and suitable for handling products containing liquid accompanied by large amounts of gas. Experimental investigations on the conveying characteristic, namely measuring the delivered volume flow as a function of the pressure difference, provide results for selected mixtures. By means of the on hand work, the influence of sorption phenomena occurring due to pressure variations alongside the conveying process on the conveying characteristics of twin-screw pumps delivering mixtures of oil and gases is measured. The employed gases are air and carbon dioxide, which differ strongly in solubility in oil. All experiments are conducted in a closed loop test facility, where oil and gas volume flows are mixed before the inlet and separated after the outlet of the multiphase pump. In order to simulate the influence of the suction side pressure drop in the reservoir on the conveying characteristic, packed beds are employed as oil-filed model. Sorption processes inside of the oil-field model and within the multiphase pump affect the conveying behaviour significantly. The two-phase flow in the inlet and outlet pipe is visualised by means of a capacitance tomography system. Results show that the oil fraction of the total delivered volume flow is decreased due to desorption at the pump inlet. The gas fraction at the pump outlet is further decreased due to absorption. Experimental results are compared to calculated solubilities of the on-hand gases in oil and to the theoretically derived gas volume flow fraction expected at the multiphase pump.

  11. High latitude pulsating aurorae revisited

    SciTech Connect

    Wu, Q.; Rosenberg, T.J. )

    1992-01-03

    Dayside auroral pulsations (10-40 s periods) have been studied for different levels of geomagnetic disturbance with N{sub 2}{sup +} 427.8 nm emission data obtained at South Pole station, Antarctica ({minus}74.2{degree} MLAT). The occurrence distribution exhibits a single peak at magnetic noon under geomagnetically quiet conditions (0 {le} Kp < 1). With increased Kp, the distribution shifts to earlier times, the peak occurring at 1000-1030 MLT for 1 {le} Kp < 4. At these higher Kp levels a secondary occurrence peak is evident in the afternoon sector between 1400 and 1600 MLT, occurring earlier as Kp increases. These results are compared with those obtained separately for pre-noon pulsations observed at Ny Alesund and post-noon pulsations observed at Ny Alesund and post-noon pulsations observed at Davis, northern and southern hemisphere sites at approximately the same magnetic latitude as South Pole. South Pole and Ny Alesund observe morning peaks at the same time and with a similar lack of Kp dependence; South Pole and Davis observe afternoon peaks with similar Kp dependence, though the peak occurs earlier at Davis. In contrast to the results from the earlier studies, the South Pole observations show larger pulsation amplitudes in the morning sector and significantly higher occurrence rates overall.

  12. [Bachelard and the mathematical pulsation].

    PubMed

    Guitart, René

    2015-01-01

    The working mathematician knows a specific gesture named « mathematical pulsation », a necessary creative moving in diagrams of thoughts and interpretations of mathematical writings. In this perspective the fact of being an object is definitely undecided, and related to the game of relations. The purpose of this paper today is to construct this pulsation, starting from the epistemology of Bachelard, concerning mathematics as well as mathematical physics. On the way, we recover links between ideas of Bachelard and more recent specific propositions by Gilles Ch-let, Charles Alunni, or René Guitart. Also are used authors like Jacques Lacan, Arthur Koestler, Alfred N. Whitehead, Charles S. Peirce. We conclude that the mathematical work consists with pulsative moving in the space of diagrams; we claim that this view is well compatible with the Bachelard's analysis of scientific knowledge: the intellectual or formal mathematical data preceeds the empirical objects, and in some sense these objects result from the pulsative gestures of the thinkers. So we finish with a categorical scheme of the pulsation.

  13. [Bachelard and the mathematical pulsation].

    PubMed

    Guitart, René

    2015-01-01

    The working mathematician knows a specific gesture named « mathematical pulsation », a necessary creative moving in diagrams of thoughts and interpretations of mathematical writings. In this perspective the fact of being an object is definitely undecided, and related to the game of relations. The purpose of this paper today is to construct this pulsation, starting from the epistemology of Bachelard, concerning mathematics as well as mathematical physics. On the way, we recover links between ideas of Bachelard and more recent specific propositions by Gilles Ch-let, Charles Alunni, or René Guitart. Also are used authors like Jacques Lacan, Arthur Koestler, Alfred N. Whitehead, Charles S. Peirce. We conclude that the mathematical work consists with pulsative moving in the space of diagrams; we claim that this view is well compatible with the Bachelard's analysis of scientific knowledge: the intellectual or formal mathematical data preceeds the empirical objects, and in some sense these objects result from the pulsative gestures of the thinkers. So we finish with a categorical scheme of the pulsation. PMID:26223414

  14. Experimental Identification of the Transmittance Matrix for any Element of the Pulsating Gas Manifold

    NASA Astrophysics Data System (ADS)

    CYKLIS, P.

    2001-07-01

    In positive-displacement compressor manifolds there are pressure pulsations due to their cyclic operation. The analysis of pressure pulsations in the compressor manifolds is important for various reasons: they directly affect the quantity of energy required for medium compression due to dynamic pressure charging, or inversely, dynamic suppression of suction and discharge processes; they cause mechanical vibrations of compressed gas piping network, they cause aerodynamic and mechanical noise; they affect the dynamics of working valves in valve compressors, they intensify the process of heat convection in heat exchangers in the gas network. The Helmholtz model used so far, which is the basis for users, who deal with pressure pulsation damping, contains many simplifying assumptions. This is because; a straight pipe segment substitutes each element of the piping system. In many cases this model is insufficient. An attempt of the analysis of other shapes was presented in references [1-3] but only simple geometry elements were considered. In other papers [4-8] the influence of the mean flow velocity caused problems. In the presented method, on the basis of pressure pulsation measurement results, firstly a division into the forward and backward going wave is determined, then the elements of the scattering (transmittance) matrix are calculated defining the installation element. This allows introducing the correction for gas mean velocity. The results of the method using correction for the gas mean velocity have been compared with the results without correction and Helmholtz model showing better accuracy.

  15. Pulsating aurora: The importance of the ionosphere

    SciTech Connect

    Stenbaek-Nielsen, H.C.

    1980-05-01

    A number of different, but mainly optical, observations made in pulsating auroras are presented. These observations indicate that active ionospheric processes are likely to play an important role in causing and/or modifying pulsating aurora.

  16. Pulsation effects on orifice measurement

    SciTech Connect

    Doelling, C. )

    1992-02-01

    The natural gas transmission industry has historically relied on the orifice as the contractual standard for custody transfer. The simplicity, reliability, low maintenance, rangeability (afforded by changing plate beta ratios) and repeatability of the orifice, together with reliable secondary systems, has dispelled flow measurement replacement attempts. While an influx of other meter types has occurred in recent years, the dominance of orifice meters dictate that any serious attempt at improved gas measurement accuracy must emphasize all phases of orifice meter installation. This paper reports on unsteady flow (pulsation) which can compromise orifice system accuracy. Instruments and error calculations for pulsation are reviewed.

  17. Pipe support

    DOEpatents

    Pollono, Louis P.

    1979-01-01

    A pipe support for high temperature, thin-walled piping runs such as those used in nuclear systems. A section of the pipe to be supported is encircled by a tubular inner member comprised of two walls with an annular space therebetween. Compacted load-bearing thermal insulation is encapsulated within the annular space, and the inner member is clamped to the pipe by a constant clamping force split-ring clamp. The clamp may be connected to pipe hangers which provide desired support for the pipe.

  18. The pulsating laminar flow in a rectangular channel

    NASA Astrophysics Data System (ADS)

    Valueva, E. P.; Purdin, M. S.

    2015-11-01

    The finite difference method is used to solve the task of the developed pulsating laminar flow in a rectangular channel. The optimum of the difference scheme parameters was determined. Data on the amplitude and phase of the longitudinal velocity oscillations, the hydraulic and friction drag coefficients, the shear stress on the wall have been obtained. Using the dimensionless value of the frequency pulsations two characteristic regimes — the quasisteady-state regime and the high-frequency regime have been identified. In the quasi-steady-state regime, the values of all hydrodynamic quantities at each instant of time correspond to the velocity value averaged over the cross section at a given moment of time. It is shown that in the high-frequency regime, the dependences on the dimensionless oscillation frequency of oscillating components of hydrodynamic quantities are identical for rectilinear channels with a different cross-sectional form (round pipe, flat and a rectangular channels). The effect of the aspect ratio of the rectangular channel sides channel on the pulsating flow dynamics has been analyzed.

  19. Erosion resistant elbow for solids conveyance

    DOEpatents

    Everett, J.W.

    1984-10-23

    An elbow and process for fabrication for use in particulate material conveyancing comprises a curved outer pipe, a curved inner pipe having the same radius of curvature as the outer pipe, concentric with and internal to the outer pipe, comprising an outer layer comprised of a first material and an inner layer comprised of a second material wherein said first material is characterized by high erosion resistance when impinged by particulate material and wherein said second material is characterized by high tensile strength and flexibility, and an inner pipe supporting means for providing support to said inner pipe, disposed between said inner pipe and said outer pipe. 4 figs.

  20. Erosion resistant elbow for solids conveyance

    DOEpatents

    Everett, James W.

    1984-10-23

    An elbow and process for fabrication for use in particulate material conveyancing comprising a curved outer pipe, a curved inner pipe having the same radius of curvature as the outer pipe, concentric with and internal to the outer pipe, comprising an outer layer comprised of a first material and an inner layer comprised of a second material wherein said first material is characterized by high erosion resistance when impinged by particulate material and wherein said second material is characterized by high tensile strength and flexibility, and an inner pipe supporting means for providing support to said inner pipe, disposed between said inner pipe and said outer pipe.

  1. Pipe Dreams.

    ERIC Educational Resources Information Center

    Milshtein, Amy

    2002-01-01

    Discusses the importance of attention to plumbing in college facilities, offering examples from various campuses. Addresses preventive maintenance, technology, and piping materials, including the debate between cast iron and PVC for drain pipes. (EV)

  2. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... and Birds to the United States § 14.107 Conveyance. (a) The animal cargo space of a conveyance used to... ensure the humane and healthful transport of the animals. (b) The cargo space shall be constructed and.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  3. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... and Birds to the United States § 14.107 Conveyance. (a) The animal cargo space of a conveyance used to... ensure the humane and healthful transport of the animals. (b) The cargo space shall be constructed and.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  4. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... and Birds to the United States § 14.107 Conveyance. (a) The animal cargo space of a conveyance used to... ensure the humane and healthful transport of the animals. (b) The cargo space shall be constructed and.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  5. 36 CFR 254.24 - Conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Conveyance. 254.24 Section 254.24 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS National Forest Townsites § 254.24 Conveyance. (a) Conveyance of the approved tract(s) may be...

  6. 36 CFR 254.24 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Conveyance. 254.24 Section 254.24 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS National Forest Townsites § 254.24 Conveyance. (a) Conveyance of the approved tract(s) may be...

  7. 36 CFR 254.24 - Conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Conveyance. 254.24 Section 254.24 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS National Forest Townsites § 254.24 Conveyance. (a) Conveyance of the approved tract(s) may be...

  8. 36 CFR 254.24 - Conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Conveyance. 254.24 Section 254.24 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS National Forest Townsites § 254.24 Conveyance. (a) Conveyance of the approved tract(s) may be...

  9. 36 CFR 254.24 - Conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Conveyance. 254.24 Section 254.24 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE LANDOWNERSHIP ADJUSTMENTS National Forest Townsites § 254.24 Conveyance. (a) Conveyance of the approved tract(s) may be...

  10. 47 CFR 13.8 - Authority conveyed.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Authority conveyed. 13.8 Section 13.8 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL RADIO OPERATORS General § 13.8 Authority conveyed. Licenses, certificates and permits issued under this part convey authority for the...

  11. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and Birds to the United States § 14.107 Conveyance. (a) The animal cargo space of a conveyance used to... ensure the humane and healthful transport of the animals. (b) The cargo space shall be constructed and.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  12. A finite element for the vibration analysis of a fluid-conveying Timoshenko beam

    NASA Astrophysics Data System (ADS)

    Stack, C. P.; Garnett, R. B.; Pawlas, G. E.

    1993-04-01

    A finite element was developed for use in the vibration analysis of fluid-conveying pipes. The pipe was represented as a Timoshenko beam possessing stiffness and mass while the fluid was idealized as incompressible and inviscid. With these simplifications the equations of motion were derived by the use of Hamilton's principle. Coriolis and centripetal terms in the equation of motion were the result of the fluid flowing in a moving frame of reference (i.e. the vibrating pipe). Formulation of a two-node, C sup 0 continuous, fluid-conveying beam element followed from the weak form of the equation of motion. Inclusion of the Coriolis term is what made this element unique with respect to previous work. Verification of the element was accomplished by modeling Coriolis mass flowmeters and then predicting their frequency and relative phase delay for the mode of operation. Results compared favorably to experimental data for commercially available Coriolis mass flowmeters.

  13. Heat transfer during nonlinear gas oscillations in a pipe open at one end

    NASA Astrophysics Data System (ADS)

    Khalimov, G. G.; Galiullin, R. G.; Podymov, V. N.

    1983-02-01

    The results of an experimental study of heat transfer in a pipe open at one end in which gas oscillations are generated by a flat piston moving harmonically are presented. The oscillograms of pressure and velocity pulsations in those sections of the pipe that are near the linear and second nonlinear resonance provide evidence of pressure and velocity discontinuities. The frequency distributions of the velocity half-amplitudes and Nusselt numbers have a resonant character, and the resonant frequencies are coincident. Heat transfer in pipes open at one end under nonlinear pulsations with the generation of periodic shock waves is adequately described by a quasi-stationary theory with allowance for thermoacoustic effects.

  14. Chaotic pulsations in stellar models

    SciTech Connect

    Buchler, J.R. )

    1990-12-01

    The irregular behavior of large-amplitude pulsating stars undergoing radial oscillations is examined theoretically, with a focus on hydrodynamic simulations of the W Virginis population II Cepheids (stars which show both regular and RV Tau characteristics). Sequences of models are constructed as one-parameter families (with luminosity, mass, and composition fixed and Teff as the control parameter) and analyzed to derive a systematic map of the bifurcation set; i.e., of the possible types of pulsations. The results are presented graphically, and it is shown that both cascades of period doubling (via destabilization of an overtone through a half-integer-type resonance) and tangent bifurcation are possible routes to chaos in these systems, depending on the stellar parameters. The general robustness of the chaotic behavior and the existence of a 'chaotic blue edge' in stellar-parameter space are demonstrated. 55 refs.

  15. Auroral pulsations from ionospheric winds

    NASA Technical Reports Server (NTRS)

    Nakada, M. P.

    1989-01-01

    The possibility that auroral pulsations are due to oscillatory electrical circuits in the ionosphere that are driven by the negative resistance of jet stream winds is examined. For the condenser plates, the highly conducting surfaces above the edges of the jet stream are postulated. The dielectric constant of the plasma between the plates is quite large. The current that is driven perpendicular to and by the jet stream closes along the plates and through Pedersen currents in the F region above the stream. This closed loop gives the inductance and resistance for the circuit. Periods of oscillation for this circuit appear to be in the range of Pc 1 to Pc 3. In accord with observations, this circuit appears to be able to limit the brightness of pulsations.

  16. Pulsating bead-based assay.

    PubMed

    Thompson, Jason A; Bau, Haim H

    2011-04-15

    In recent years, there has been a growing interest in using porous microbeads such as agarose beads as solid supports to bind target molecules from complex fluid samples. Porous beads have large surface area to volume ratios and high receptor concentrations, and they facilitate relatively high sensitivity detection and multiplexing. Unfortunately, to take full advantage of the porous beads' attributes, long incubation times are needed due to the relatively slow mass transfer of target molecules from the exterior solution into the beads' interior. To accelerate the mass transfer process, we propose a novel assay in which functionalized porous beads are periodically compressed and expanded. Preliminary experiments were carried out to compare the performance of the pulsating beads with that of conventional, nonpulsating beads. These experiments indicate that the pulsating beads significantly accelerate binding rates with minimal increase in nonspecific binding. Thus, pulsing has the potential of significantly reducing assay time.

  17. Heat transfer investigation in pipe by IR thermography

    NASA Astrophysics Data System (ADS)

    Koppel, Tiit; Ainola, Leo; Ekholm, Ari; Lahdeniemi, Matti

    2000-03-01

    The IR-thermography has proved to be a useful contactless instrument in fluid flow research, especially for investigation of heat transfer processes. Series of experimental measurements of suddenly accelerated and pulsating pipe flow were made at Satakunta Polytechnic, Technology in Pori, Finland, with this aim.

  18. Pulsating Helium Atmosphere White Dwarfs

    NASA Astrophysics Data System (ADS)

    Provencal, Judith; Montgomery, Michael H.; Bischoff-Kim, Agnes; Shipman, Harry; Nitta, Atsuko; Whole Earth Telescope Collaboration

    2015-08-01

    The overwhelming majority of all stars currently on the main sequence as well as those from earlier generations will or have ended their stellar lives as white dwarf stars. White dwarfs are rich forensic laboratories linking the history and future evolution of our Galaxy. Their structure and atmospheric composition provide evidence of how the progenitors lived, how they evolved, and how they died. This information reveals details of processes governing the behavior of contemporary main sequence stars. Combined with their distribution in luminosity/temperature, white dwarfs strongly constrain models of galactic and cosmological evolution.GD358 is among the brightest (mv =13.7) and best studied of the pulsating white dwarfs. This helium atmoshere pulsator (DBV) has an extensive photometric database spanning 30 years, including nine multisite Whole Earth Telescope campaigns. GD358 exhibits a range of behaviors, from drastic changes in excited pulsation modes to variable multiplet splittings. We use GD358 as a template for an examination of the DBV class, combining photometric results with recent COS spectroscopy. The results present new questions concerning DB formation and evolution.

  19. Pulsating Hot Subdwarfs in Omega Centauri

    NASA Astrophysics Data System (ADS)

    Randall, S. K.; Calamida, A.; Fontaine, G.; Monelli, M.; Bono, G.; Alonso, M. L.; Van Grootel, V.; Brassard, P.; Chayer, P.; Catelan, M.; Littlefair, S.; Dhillon, V. S.; Marsh, T. R.

    2016-06-01

    We recently discovered the first globular cluster hot subdwarf pulsators in Omega Centauri (ω Cen). These stars were initially thought to belong to the class of rapidly pulsating subdwarf B stars, which are well established among the field star population and have become showcases for asteroseismology. However, our spectroscopic analysis revealed the ω Cen variables to be significantly hotter than expected, indicating that they form a new class of subdwarf O pulsators clustered around 50 000 K, not known among the field star population. Non-adiabatic pulsation modelling suggests that the driver for the pulsations occurs via the same iron opacity mechanism that is at work in the rapidly pulsating subdwarf B stars.

  20. The morphology of displays of pulsating auroras.

    NASA Technical Reports Server (NTRS)

    Cresswell, G. R.

    1972-01-01

    An auroral substorm generates displays of pulsating auroras in ways which show a dependence upon both local time and latitude relative to the auroral oval. For several hours after midnight pulsating auroras can be observed in the wake of poleward expansions or within equatorward spreading diffuse envelopes of meridional extent of several hundred kilometers. As the dawn meridian is approached the displays of pulsating auroras tend increasingly to be comprised of distinct eastward drifting patches easily recorded by all-sky cameras.

  1. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

  2. Characteristics of low-temperature short heat pipes with a nozzle-shaped vapor channel

    NASA Astrophysics Data System (ADS)

    Seryakov, A. V.

    2016-01-01

    This paper presents the results of experimental and numerical studies of heat transfer and swirling pulsating flows in short low-temperature heat pipes whose vapor channels have the form of a conical nozzle. It has been found that as the evaporator of the heat pipe is heated, pressure pulsations occur in the vapor channel starting at a certain threshold value of the heat power, which is due to the start of boiling in the evaporator. The frequency of the pulsations has been measured, and their dependence on the superheat of the evaporator has been determined. It has been found that in heat pipes with a conical vapor channel, pulsations occur at lower evaporator superheats and the pulsation frequency is greater than in heat pipes of the same size with a standard cylindrical vapor channel. It has been shown that the curve of the heat-transfer coefficient versus thermal load on the evaporator has an inflection corresponding to the start of boiling in the capillary porous evaporator of the heat pipe.

  3. Flutter of articulated pipes at finite amplitude

    NASA Technical Reports Server (NTRS)

    Rousselet, J.; Herrmann, G.

    1975-01-01

    Previous studies of the behavior of pipes conveying fluid have assumed that the fluid velocity relative to the pipe is a known quantity and is unaffected by the motion of the pipe. This approach eliminates the need to find the flow equations of motion, and is adequate for infinitesimal transverse amplitudes of motion of the pipe system, but is incapable of predicting what will be the effect of larger amplitudes. This last shortcoming may be of importance when flow velocities are near critical velocities, that is, velocities at which the system begins to flutter. It is the purpose of the present study to investigate in greater detail the dynamic behavior of pipes in the vicinity of critical velocities.

  4. Pipe connector

    DOEpatents

    Sullivan, Thomas E.; Pardini, John A.

    1978-01-01

    A safety test facility for testing sodium-cooled nuclear reactor components includes a reactor vessel and a heat exchanger submerged in sodium in the tank. The reactor vessel and heat exchanger are connected by an expansion/deflection pipe coupling comprising a pair of coaxially and slidably engaged tubular elements having radially enlarged opposed end portions of which at least a part is of spherical contour adapted to engage conical sockets in the ends of pipes leading out of the reactor vessel and in to the heat exchanger. A spring surrounding the pipe coupling urges the end portions apart and into engagement with the spherical sockets. Since the pipe coupling is submerged in liquid a limited amount of leakage of sodium from the pipe can be tolerated.

  5. 36 CFR 17.8 - Conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... leasehold or freehold interest shall be by lease or deed, as appropriate, at the highest bid price, but not less than fair market value. All conveyance of leasehold or freehold interests shall contain such terms... protect the natural, historic, cultural or other values present on the lands. All conveyances shall...

  6. 36 CFR 17.8 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... leasehold or freehold interest shall be by lease or deed, as appropriate, at the highest bid price, but not less than fair market value. All conveyance of leasehold or freehold interests shall contain such terms... protect the natural, historic, cultural or other values present on the lands. All conveyances shall...

  7. 36 CFR 17.8 - Conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Conveyance. 17.8 Section 17.8 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR CONVEYANCE OF... with the purpose for which the area was authorized by Congress. The conveyancing or leasing...

  8. Total-pressure-tube averaging in pulsating flows.

    NASA Technical Reports Server (NTRS)

    Krause, L. N.

    1973-01-01

    A number of total-pressure tubes were tested in a nonsteady flow generator in which the fraction of period that pressure is a maximum is approximately 0.8, thereby simulating turbomachine-type flow conditions. The tests were performed at a pressure level of 1 bar, for Mach numbers up to near 1, and frequencies up to 3 kHz. Most of the tubes indicated a pressure which was higher than the true average. Organ-pipe resonances which further increased the indicated pressure were encountered within the tubes at discrete frequencies. There was no obvious combination of tube diameter, length, and/or geometry variation used in the tests which resulted in negligible averaging error. A pneumatic-type probe was found to measure true average pressure, and is suggested as a comparison instrument to determine whether nonlinear averaging effects are serious in unknown pulsation profiles.

  9. Models of cylindrical bubble pulsation

    PubMed Central

    Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hay, Todd A.; Hamilton, Mark F.

    2012-01-01

    Three models are considered for describing the dynamics of a pulsating cylindrical bubble. A linear solution is derived for a cylindrical bubble in an infinite compressible liquid. The solution accounts for losses due to viscosity, heat conduction, and acoustic radiation. It reveals that radiation is the dominant loss mechanism, and that it is 22 times greater than for a spherical bubble of the same radius. The predicted resonance frequency provides a basis of comparison for limiting forms of other models. The second model considered is a commonly used equation in Rayleigh-Plesset form that requires an incompressible liquid to be finite in extent in order for bubble pulsation to occur. The radial extent of the liquid becomes a fitting parameter, and it is found that considerably different values of the parameter are required for modeling inertial motion versus acoustical oscillations. The third model was developed by V. K. Kedrinskii [Hydrodynamics of Explosion (Springer, New York, 2005), pp. 23–26] in the form of the Gilmore equation for compressible liquids of infinite extent. While the correct resonance frequency and loss factor are not recovered from this model in the linear approximation, it provides reasonable agreement with observations of inertial motion. PMID:22978863

  10. A Planet Found by Pulsations

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-10-01

    Searching for planets around very hot stars is much more challenging than looking around cool stars. For this reason, the recent discovery of a planet around a main-sequence A star is an important find both because of its unique position near the stars habitable zone, and because of the way in which the planet was discovered.Challenges in VariabilityIn the past three decades, weve discovered thousands of exoplanets yet most of them have been found around cool stars (like M dwarfs) or moderate stars (like G stars like our Sun). Very few of the planets that weve found orbit hot stars; in fact, weve only discovered ~20 planets orbiting the very hot, main-sequence A stars.The instability strip, indicated on an H-R diagram. Stellar classification types are listed across the bottom of the diagram. Many main-sequence A stars reside in the instability strip. [Rursus]Why is this? We dont expect that main-sequence A stars host fewer planets than cooler stars. Instead, its primarily because the two main techniques that we use to find planets namely, transits and radial velocity cant be used as effectively on the main-sequence A stars that are most likely to host planets, because the luminosities of these stars are often variable.These stars can lie on whats known as the classical instability strip in the Herzsprung-Russell diagram. Such variable stars pulsate due to changes in the ionization state of atoms deep in their interiors, which causes the stars to puff up and then collapse back inward. For variable main-sequence A stars, the periods for these pulsations can be several to several tens of times per day.These very pulsations that make transits and radial-velocity measurements so difficult, however, can potentially be used to detect planets in a different way. Led by Simon Murphy (University of Sydney, Australia and Aarhus University, Denmark), a team of scientists has recently detected the first planet ever to be discovered around a main-sequence A star from the timing

  11. Nonlinear Analysis of Pulsating White Dwarf Lightcurves

    NASA Astrophysics Data System (ADS)

    Provencal, J. L.; Montgomery, M. H.; Shipman, H.; WET TEam

    2015-06-01

    Convection remains one of the largest sources of theoretical uncertainty in our understanding of stellar physics. For example, Bergeron (1995) show that basic parameters such as flux, line profiles, energy distribution, color indices, and equivalent widths are extremely sensitive to the assumed convective parameterization. This is compelling, since we use our knowledge of these basic parameters to calibrate white dwarf cooling sequences, provide detailed estimates for the ages of individual white dwarfs, and determine the age of the Galactic disk. The Whole Earth Telescope (WET) is engaged in a long term project to empirically calibrate the physical properties of convection in pulsating white dwarfs by combining asteroseismology and analysis of nonlinear light curves. Nonsinusoidal distortions, in the form of narrow peaks and wider valleys, are observed in many pulsating white dwarf light curves. These are a reflection of the local depth of the convection zone, a value which varies during a pulsation cycle. Applying asteroseismology and convective light curve fitting to a wide sample of pulsating white dwarfs provides an empirical map of how the convective response time (the convection zone “depth”) varies as a function of effective temperature, and this can be compared with theoretical models, both MLT and hydrodynamic. This project has resulted in a large database of white dwarf lightcurves and pulsation frequencies. We present current results for DA and DB pulsators, and provide a few examples of interesting pulsation behavior seen along the way.

  12. CHARACTERIZING PULSATING MIXING OF SLURRIES

    SciTech Connect

    Bamberger, Judith A.; Meyer, Perry A.

    2007-12-01

    This paper describes the physical properties for defining the operation of a pulse jet mixing system. Pulse jet mixing operates with no moving parts located in the vessel to be mixed. Pulse tubes submerged in the vessel provide a pulsating flow due to a controlled combination of applied pressure to expel the fluid from the pulse tube nozzle followed by suction to refill the pulse tube through the same nozzle. For mixing slurries nondimensional parameters to define mixing operation include slurry properties, geometric properties and operational parameters. Primary parameters include jet Reynolds number and Froude number; alternate parameters may include particle Galileo number, particle Reynolds number, settling velocity ratio, and hindered settling velocity ratio. Rating metrics for system performance include just suspended velocity, concentration distribution as a function of elevation, and blend time.

  13. Pipe downchute stormwater drainage system

    SciTech Connect

    Gross, W.E.

    1995-12-31

    SCS Engineers (SCS) was provided with the challenge of developing a completely enclosed pipe downchute system for stormwater drainage at the Fresh Kills Landfill in New York City, the largest landfill in the world. With a total landfill drainage subshed totaling over 1000 acres, and an average yearly precipitation at the site of approximately 4.2 feet, the final constructed stormwater drainage system would capture and convey over 591 million gallons of stormwater runoff per year, and discharge it into 17 stormwater basins.This paper describes the drainage system.

  14. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than $57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was $28,706, and that figures out to a cost reduction.

  15. Solar wind controlled pulsations: A review

    SciTech Connect

    Odera, T.J.

    1986-02-01

    Studies of the solar wind controlled Pc 3, 4 pulsations by early and recent researchers are highlighted. The review focuses on the recent observations, which cover the time during the International Magnetospheric Study (IMS). Results from early and recent observations agree on one point, that is, that the Pc 3, 4 pulsations are influenced by three main solar wind parameters, namely, the solar wind velocity V/sub 5w/, the IMF orientation theta/sub x/B, and magnitude B. The results can be interpreted, preferably, in terms of an external origin for Pc 3, 4 pulsations. This implies, essentially, the signal model, which means that the pulsations originate in the upstream waves (in the interplanetary medium) and are transported by convection to the magnetopause, where they couple to oscillations of the magnetospheric field lines.

  16. Small-scale Features in Pulsating Aurora

    NASA Astrophysics Data System (ADS)

    Jones, S.; Jaynes, A. N.; Knudsen, D. J.; Trondsen, T.; Lessard, M.

    2011-12-01

    A field study was conducted from March 12-16, 2002 using a narrow-field intensified CCD camera installed at Churchill, Manitoba. The camera was oriented along the local magnetic zenith where small-scale black auroral forms are often visible. This analysis focuses on such forms occurring within a region of pulsating aurora. The observations show black forms with irregular shape and nonuniform drift with respect to the relatively stationary pulsating patches. The pulsating patches occur within a diffuse auroral background as a modulation of the auroral brightness in a localized region. The images analyzed show a decrease in the brightness of the diffuse background in the region of the pulsating patch at the beginning of the 'off' phase of the modulation. Throughout the off phase the brightness of the diffuse aurora gradually increases back to the average intensity. The time constant for this increase is measured as the first step toward determining the physical process.

  17. A motion picture presentation of magnetic pulsations

    NASA Technical Reports Server (NTRS)

    Suzuki, A.; Kim, J. S.; Sugura, M.; Nagano, H.

    1981-01-01

    Using the data obtained from the IMS North American magnetometer network stations at high latitudes, a motion picture was made by a computer technique, describing time changes of Pc5 and Pi3 magnetic pulsation vectors. Examples of pulsation characteristics derived from this presentation are regional polarization changes including shifts of polarization demarcation lines, changes in the extent of an active region and its movement with time.

  18. Spectral element modelling and analysis of a pipeline conveying internal unsteady fluid

    NASA Astrophysics Data System (ADS)

    Lee, U.; Park, J.

    2006-02-01

    In this paper, a spectral element model is developed for the uniform straight pipelines conveying internal unsteady fluid. Four coupled pipe-dynamics equations are derived first by using the Hamilton's principle and the principles of fluid mechanics. The transverse displacement, the axial displacement, the fluid pressure and the fluid velocity are all considered as the dependent variables. The coupled pipe-dynamics equations are then linearized about the steady-state values of the fluid pressure and velocity. As the final step, the spectral element model represented by the exact dynamic stiffness matrix, which is often called spectral element matrix, is formulated by using the frequency-domain solutions of the linearized pipe-dynamics equations. The fast Fourier transform (FFT)-based spectral dynamic analyses are conducted to evaluate the accuracy of the present spectral element model and also to investigate the structural dynamic characteristics and the internal fluid transients of an example pipeline system.

  19. Two new extremely hot pulsating white dwarfs

    NASA Technical Reports Server (NTRS)

    Bond, H. E.; Grauer, A. D.; Green, R. F.; Liebert, J. W.

    1984-01-01

    High speed photometry of the extremely hot, nearly degenerate stars PG 1707 + 427 and PG 2131 + 066 reveals that they are low-amplitude pulsating variables. Power spectral analysis shows both to be multiperiodic, with dominant periods of 7.5 and 6.4-6.9 minutes, respectively. Together with the known pulsators PG 1159 - 035 and the central star of the planetary nebula Kohoutek 1-16, these objects define a new pulsational instability strip at the hot edge of the H-R diagram. The variations of these objects closely resemble those of the much cooler pulsating ZZ Ceti DA white dwarfs; both groups are probably nonradial g-mode pulsators. Evolutionary contraction of the PG 1159 - 035 variables may lead to period changes that would be detectable in as little as 1 year. The optical and IUE spectra of the PG 1159 - 035 variables are characterized by absorption lines of C IV and other CNO ions, indicating radiative levitation of species heavier than helium. He II is also present in the spectra, but the hydrogen Balmer lines are absent. Effective temperatures near 100,000 K are required, and the He II 4686 A profiles indicate log g greater than 6. These helium-rich pulsators form the hottest known subgroup of the DO white dwarfs.

  20. Piping Connector

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A complex of high pressure piping at Stennis Space Center carries rocket propellants and other fluids/gases through the Center's Component Test Facility. Conventional clamped connectors tend to leak when propellant lines are chilled to extremely low temperatures. Reflange, Inc. customized an existing piping connector to include a secondary seal more tolerant of severe thermal gradients for Stennis. The T-Con connector solved the problem, and the company is now marketing a commercial version that permits testing, monitoring or collecting any emissions that may escape the primary seal during severe thermal transition.

  1. Pipe gripper

    DOEpatents

    Moyers, S.M.

    1975-12-16

    A device for gripping the exterior surface of a pipe or rod is described which has a plurality of wedges, each having a concave face which engages the outer surface of the pipe and each having a smooth face opposing the concave face. The wedges are seated on and their grooved concave faces are maintained in circular alignment by tapered axial segments of an opening extending through a wedge-seating member. The wedges are allowed to slide across the tapered axial segments so that such a sliding movement acts to vary the diameter of the circular alignment.

  2. Heat Pipes

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

  3. Self-sustained aero-acoustic pulsations in gas transport systems: Experimental study of the influence of closed side branches

    NASA Astrophysics Data System (ADS)

    Bruggeman, J. C.; Hirschberg, A.; van Dongen, M. E. H.; Wijnands, A. P. J.; Gorter, J.

    1991-11-01

    A theoretical model is proposed for the aero-acoustic sources responsible for low-frequency self-sustained pulsations in pipes with closed side branches. The theory successfully explains the acoustic and hydrodynamic conditions for resonance in experiments with a single side branch. It also predicts the order of magnitude of the pulsation amplitude and the effect of losses due to friction and radiation. A high pulsation level, with acoustic velocities of the order of magnitude of the main flow, is observed in a double side branch set-up when the edges at the junctions are rounded. When in the double side branch set-up the rounded upstream edge of the second T-joint is replaced by a sharp edge, the pulsation amplitude is reduced by a factor of five. This effect, which can be explained with the theory of vortex sound, leads us to the design of spoilers. Various "spoilers" have been tested in scale model and full scale experiments. Some of these reduce the pulsation level by 40 dB.

  4. Russian Pulsating Mixer Pump Deployment in the Gunite and Associated Tanks at ORNL

    SciTech Connect

    Hatchell, Brian K.; Lewis, Ben; Johnson, Marshall A.; Randolph, J. G.

    2001-03-01

    In FY 1998, Pulsating Mixer Pump (PMP) technology, consisting of a jet mixer powered by a reciprocating air supply, was selected for deployment in one of the Gunite and Associated Tanks at Oak Ridge National Laboratory (ORNL) to mobilize settled solids. The pulsating mixer pump technology was identified during FY 1996 and FY 1997 technical exchanges between the U.S. Department of Energy (DOE) Tanks Focus Area Retrieval and Closure program, the DOE Environmental Management International Programs, and delegates from Russia as a promising technology that could be implemented in the DOE complex. During FY 1997, the pulsating mixer pump technology, provided by the Russian Integrated Mining Chemical Company, was tested at Pacific Northwest National Laboratory (PNNL) to observe its ability to suspend settled solids. Based on the results of this demonstration, ORNL and DOE staff determined that a modified pulsating mixer pump would meet project needs for remote sludge mobilization of Gunite tank sludge and reduce the cost of operation and maintenance of more expensive mixing systems. The functions and requirements of the system were developed by combining the results and recommendations from the pulsating mixer pump demonstration at PNNL with the requirements identified by staff at ORNL involved with the remediation of the Gunite and Associated Tanks. The PMP is comprised of a pump chamber, check valve, a working gas supply pipe, a discharge manifold, and four jet nozzles. The pump uses two distinct cycles, fill and discharge, to perform its mixing action. During the fill cycle, vacuum is applied to the pump chamber by an eductor, which draws liquid into the pump. When the liquid level inside the chamber reaches a certain level, the chamber is pressurized with compressed air to discharge the liquid through the jet nozzles and back into the tank to mobilize sludge and settled solids.

  5. 24 CFR 203.401 - Amount of payment-conveyed and non-conveyed properties.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Amount of payment-conveyed and non-conveyed properties. 203.401 Section 203.401 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND...

  6. Predictions of fully developed pulsating flow with the aid of low-Reynolds number turbulence models

    NASA Astrophysics Data System (ADS)

    Bartosik, A. S.; Sobocinski, R.; Wanik, A. J.

    Four low-Reynolds-number turbulence models are studied to investigate the fully developed pulsating turbulent flow of an incompressible Newtonian fluid in a circular pipe. In these models, the Reynolds stress is related to the local velocity gradient by the turbulent viscosity, and the turbulent viscosity is determined using modeled transport equations for the kinetic energy of turbulence and its dissipation rate. The models of Launder and Sharma (1974) and Chien (1982) are found to perform better than those of Hassid and Poreh (1978 and 1975).

  7. DEVICE FOR CONVEYING AND ROTATING OBJECTS

    DOEpatents

    Frantz, C.E.; Roslund, J.

    1958-01-21

    A device is described for conveying cylindrical material with a combined rotary and axial motion. The material rides on a series of balls which are retained in a guide plate and rotated by bearing against a rotating drum. The drum has a series of conical sections or grooves cut in its outer surface on which the balls ride. The grooves and balls match in such a way that all the balls are caused to rotate about an axis at an angle to the drum axis. This skewed rotation of the ball imparts a longitudinal as well as a rotary motion to the cylinders being conveyed.

  8. 9 CFR 88.3 - Standards for conveyances.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION OF EQUINES FOR SLAUGHTER § 88.3 Standards for conveyances. (a) The animal cargo space of... conveyance that has the animal cargo space divided into two or more stacked levels, except that conveyances... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Standards for conveyances....

  9. 9 CFR 88.3 - Standards for conveyances.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION OF EQUINES FOR SLAUGHTER § 88.3 Standards for conveyances. (a) The animal cargo space of... conveyance that has the animal cargo space divided into two or more stacked levels, except that conveyances... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Standards for conveyances....

  10. 24 CFR 203.366 - Conveyance of marketable title.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Conveyance of marketable title. 203... Conveyance of marketable title. (a) Satisfactory conveyance of title and transfer of possession. The mortgagee shall tender to the Commissioner a satisfactory conveyance of title and transfer of possession...

  11. HST spectrophotometry of accreting white dwarf pulsators

    NASA Astrophysics Data System (ADS)

    Mukadam, Anjum S.; Szkody, Paula; Gaensicke, Boris T.

    2015-01-01

    The discovery of non-radial pulsations in cataclysmic variables has opened a new venue of opportunity to probe the stellar parameters of accreting variable white dwarfs using asteroseismic techniques. A unique model fit to the observed periods of the variable white dwarf can reveal information about the stellar mass, core composition, age, rotation rate, magnetic field strength, and distance. Mode identification is an essential step in determining an unambiguous model fit, that could be achieved by determining optical and ultra-violet pulsation amplitudes. We will be presenting our results on ultra-violet HST observations acquired with contemporaneous ground based optical data for several cataclysmic variables. The HST spectrophotometry also yields the effective temperatures of the accreting white dwarfs, allowing us to improve our present determination of the instability strip for accreting pulsators. We thank NASA for the grant HST-GO12870 that has supported this research.

  12. 33 CFR 211.147 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Conveyance. 211.147 Section 211.147 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION WITH CIVIL WORKS PROJECTS...

  13. 33 CFR 211.80 - Conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Conveyance. 211.80 Section 211.80 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION WITH CIVIL WORKS PROJECTS Sale of Lands in Reservoir...

  14. 33 CFR 211.80 - Conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Conveyance. 211.80 Section 211.80 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION WITH CIVIL WORKS PROJECTS Sale of Lands in Reservoir...

  15. 33 CFR 211.80 - Conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Conveyance. 211.80 Section 211.80 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION WITH CIVIL WORKS PROJECTS Sale of Lands in Reservoir...

  16. Pneumatic conveying of pulverized solvent refined coal

    DOEpatents

    Lennon, Dennis R.

    1984-11-06

    A method for pneumatically conveying solvent refined coal to a burner under conditions of dilute phase pneumatic flow so as to prevent saltation of the solvent refined coal in the transport line by maintaining the transport fluid velocity above approximately 95 ft/sec.

  17. Buried pipe design

    SciTech Connect

    Mosler, A.P.

    1990-01-01

    This book covers basic information on proper, cost-effective design of buried-pipe systems for underground fluid transportation. Examines various pipe products available. Discusses soil engineering and piping mechanics. Specific topics include pipe-wall stresses and strains; design bases; rigid- and flexible-pipe analysis; soil pressure; and longitudinal, wheel, expansive-soil, and frost loading.

  18. Benefit of pulsation in soft corals.

    PubMed

    Kremien, Maya; Shavit, Uri; Mass, Tali; Genin, Amatzia

    2013-05-28

    Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (Movie S1), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsation motions thrust water upward and enhance mixing across the coral-water boundary layer. The induced upward motion effectively prevents refiltration of water by neighboring polyps, while the intensification of mixing, together with the upward flow, greatly enhances the coral's photosynthesis. A series of controlled laboratory experiments with the common xeniid coral Heteroxenia fuscescens showed that the net photosynthesis rate during pulsation was up to an order of magnitude higher than during the coral's resting, nonpulsating state. This enhancement diminished when the concentration of oxygen in the ambient water was artificially raised, indicating that the enhancement of photosynthesis was due to a greater efflux of oxygen from the coral tissues. By lowering the internal oxygen concentration, pulsation alleviates the problem of reduced affinity of ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) to CO2 under conditions of high oxygen concentrations. The photosynthesis-respiration ratio of the pulsating H. fuscescens was markedly higher than the ratios reported for nonpulsating soft and stony corals. Although pulsation is commonly used for locomotion and filtration in marine mobile animals, its occurrence in sessile (bottom-attached) species is limited to members of the ancient phylum Cnidaria, where it is used to accelerate water and enhance physiological processes.

  19. Benefit of pulsation in soft corals

    PubMed Central

    Kremien, Maya; Shavit, Uri; Mass, Tali; Genin, Amatzia

    2013-01-01

    Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (Movie S1), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsation motions thrust water upward and enhance mixing across the coral–water boundary layer. The induced upward motion effectively prevents refiltration of water by neighboring polyps, while the intensification of mixing, together with the upward flow, greatly enhances the coral’s photosynthesis. A series of controlled laboratory experiments with the common xeniid coral Heteroxenia fuscescens showed that the net photosynthesis rate during pulsation was up to an order of magnitude higher than during the coral’s resting, nonpulsating state. This enhancement diminished when the concentration of oxygen in the ambient water was artificially raised, indicating that the enhancement of photosynthesis was due to a greater efflux of oxygen from the coral tissues. By lowering the internal oxygen concentration, pulsation alleviates the problem of reduced affinity of ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO) to CO2 under conditions of high oxygen concentrations. The photosynthesis–respiration ratio of the pulsating H. fuscescens was markedly higher than the ratios reported for nonpulsating soft and stony corals. Although pulsation is commonly used for locomotion and filtration in marine mobile animals, its occurrence in sessile (bottom-attached) species is limited to members of the ancient phylum Cnidaria, where it is used to accelerate water and enhance physiological processes. PMID:23610420

  20. Linear nonradial pulsation theory. Lecture 7

    SciTech Connect

    Cox, A.N.

    1983-03-14

    Many of the upper main-sequence stars pulsate in spheroidal nonradial modes. We know this to be true in numerous cases, as we have tabulated for the ..beta.. Cephei and delta Scuti variables in previous lectures. However, we cannot identify the actual mode for any star except for the low-order pressure p and f modes of our sun. It remains a great challenge to clearly state what really is occurring, in the process we learn more about how stars evolve and pulsate.

  1. A model for dynamic analysis of buried and partially buried piping systems

    SciTech Connect

    Zhou, Z.J.; Harvey, D.P.

    1996-12-31

    Compressor station yard piping may be subject to low frequency excitation forces due to acoustical resonance with flow generated sources. Compression facility yard piping in the gas transmission system of NOVA Gas Transmission Ltd. (NGTL) consists of a combination of above ground and buried piping with nominal sizes ranging from 8 to 48 inches. Vibration control is implemented at the design state by attenuation of pulsation sources, acoustic detuning through adjustment of piping the configuration, and stiffness modification through piping supports. Dynamic analysis is often required to determine the need for vibration control and the best design option. This paper reviews the dynamic analysis model employed at NGTL at the present time and presents a proposed model for dynamic analysis of buried and partially buried piping systems. The model is based on beam and soil spring models. Emphasis is on determination of dynamic soil properties and soil spring constants. The effects of dynamic soil behavior are demonstrated by a simple example.

  2. Observations of ''granular jump'' in the pneumatic conveying system

    SciTech Connect

    Jaworski, Artur J.; Dyakowski, Tomasz

    2007-08-15

    This paper presents a preliminary study of a previously unreported phenomenon of the ''gas driven granular jump'', observed in the gas-solids flow within the pneumatic conveying system. From the phenomenological point of view, it resembles the already known processes such as hydraulic jumps in shallow water or granular jumps in granular flows in chutes or avalanches (although it seems most appropriate to explain it by analogy to a propagating granular bore). Clearly, unlike in classical phenomena of this type, the flow itself is driven by the aerodynamic forces related to the gas flow and the behaviour of the front of the ''jump'' is modified significantly by their presence. A series of high-speed camera visualisations are presented, which focus on this unusual behaviour of the flow on the border-line between cluster and stratified flow regimes in a horizontal pipe. Some similarities are drawn between the observed phenomenon and the broader class of problems exhibiting transition between super- and sub-critical flows. The fluid dynamical aspects and possible mechanisms behind the new phenomenon are discussed and the results obtained are compared quantitatively with simple theoretical models. (author)

  3. X-ray Pulsation Searches with NICER

    NASA Astrophysics Data System (ADS)

    Ray, Paul S.; Arzoumanian, Zaven

    2016-04-01

    The Neutron Star Interior Composition Explorer (NICER) is an X-ray telescope with capabilities optimized for the study of the structure, dynamics, and energetics of neutron stars through high-precision timing of rotation- and accretion-powered pulsars in the 0.2-12 keV band. It has large collecting area (twice that of the XMM-Newton EPIC-pn camera), CCD-quality spectral resolution, and high-precision photon time tagging referenced to UTC through an onboard GPS receiver. NICER will begin its 18-month prime mission as an attached payload on the International Space Station around the end of 2016. I will describe the science planning for the pulsation search science working group, which is charged with searching for pulsations and studying flux modulation properties of pulsars and other neutron stars. A primary goal of our observations is to detect pulsations from new millisecond pulsars that will contribute to NICER’s studies of the neutron star equation of state through pulse profile modeling. Beyond that, our working group will search for pulsations in a range of source categories, including LMXBs, new X-ray transients that might be accreting millisecond pulsars, X-ray counterparts to unassociated Fermi LAT sources, gamma-ray binaries, isolated neutron stars, and ultra-luminous X-ray sources. I will survey our science plans and give an overview of our planned observations during NICER’s prime mission.

  4. Blackworms, Blood Vessel Pulsations and Drug Effects.

    ERIC Educational Resources Information Center

    Lesiuk, Nalena M.; Drewes, Charles D.

    1999-01-01

    Introduces the freshwater oligochaete worm, lumbriculus variegatus (common name: blackworms), an organism that is well suited for classroom study because of its closed circulatory system. Describes a set of simple, fast, noninvasive, and inexpensive methods for observing pulsations of the worm's dorsal blood vessels under baseline conditions, and…

  5. VOLUME COMPENSATING MEANS FOR PULSATING PUMPS

    DOEpatents

    Weaver, D.L.W.; MacCormack, R.S. Jr.

    1959-12-01

    A double diaphragm, two-liquid pulsating pump for remote control use, having as an improvement an apparatus for maintaining constant the volume of the liquid such as kerosene between the two diaphragms is described. Phase difficulties encountered in the operation of such pumps when the volume of the liquid is altered by changes in temperature are avoided.

  6. Ultrasonic pipe assessment

    DOEpatents

    Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

    2003-12-23

    An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

  7. 9 CFR 88.3 - Standards for conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION OF EQUINES FOR SLAUGHTER § 88.3 Standards for conveyances. (a) The animal cargo space of... slaughtering facilities must not be transported in any conveyance that has the animal cargo space divided into... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Standards for conveyances....

  8. 38 CFR 3.808 - Automobiles or other conveyances; certification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... necessary to assist the eligible person into or out of the automobile or other conveyance, regardless of... conveyances; certification. 3.808 Section 3.808 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility...

  9. 38 CFR 36.4323 - Election to convey security.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Election to convey... Election to convey security. (a) If the holder acquires the property that secured the guaranteed loan at... accept conveyance of the property if the holder fails to notify the Secretary of its election within...

  10. 38 CFR 36.4323 - Election to convey security.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2012-07-01 2012-07-01 false Election to convey... Election to convey security. (a) If the holder acquires the property that secured the guaranteed loan at... accept conveyance of the property if the holder fails to notify the Secretary of its election within...

  11. 38 CFR 36.4323 - Election to convey security.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2014-07-01 2014-07-01 false Election to convey... Election to convey security. (a) If the holder acquires the property that secured the guaranteed loan at... accept conveyance of the property if the holder fails to notify the Secretary of its election within...

  12. 9 CFR 88.3 - Standards for conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION OF EQUINES FOR SLAUGHTER § 88.3 Standards for conveyances. (a) The animal cargo space of... slaughtering facilities must not be transported in any conveyance that has the animal cargo space divided into... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Standards for conveyances....

  13. 19 CFR 162.22 - Seizure of conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... applicability. If it shall appear to any officer authorized to board conveyances and make seizures that there... conveyance, or any merchandise on board of or imported by such vessel, vehicle, aircraft, or other conveyance... bareboat charter by the Maritime Administration and operated for its account becomes liable for the...

  14. 30 CFR 56.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Lowering conveyances by the brakes. 56.19065... Hoisting Hoisting Procedures § 56.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  15. 30 CFR 57.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Lowering conveyances by the brakes. 57.19065... Hoisting Hoisting Procedures § 57.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  16. 30 CFR 56.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Lowering conveyances by the brakes. 56.19065... Hoisting Hoisting Procedures § 56.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  17. 30 CFR 57.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Lowering conveyances by the brakes. 57.19065... Hoisting Hoisting Procedures § 57.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  18. 30 CFR 56.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Lowering conveyances by the brakes. 56.19065... Hoisting Hoisting Procedures § 56.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  19. 30 CFR 57.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Lowering conveyances by the brakes. 57.19065... Hoisting Hoisting Procedures § 57.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  20. 30 CFR 57.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lowering conveyances by the brakes. 57.19065... Hoisting Hoisting Procedures § 57.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  1. 30 CFR 56.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Lowering conveyances by the brakes. 56.19065... Hoisting Hoisting Procedures § 56.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  2. 30 CFR 57.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Lowering conveyances by the brakes. 57.19065... Hoisting Hoisting Procedures § 57.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  3. 30 CFR 56.19065 - Lowering conveyances by the brakes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Lowering conveyances by the brakes. 56.19065... Hoisting Hoisting Procedures § 56.19065 Lowering conveyances by the brakes. Conveyances shall not be lowered by the brakes alone except during emergencies....

  4. Evaluation of hydro-mechanical pulsation for rocket injector research

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew B.

    The Propulsion Research Center at the University of Alabama in Huntsville has designed and built a hydro-mechanical pulsator to simulate the pressure fluctuations created by high frequency combustion instability. The pressure response characteristics were evaluated in an atmospheric test rig using filtered de-ionized water as the working fluid. The outlet of the pulsator was connected to a swirl injector post to provide downstream flow resistance. Previous low pressure and mass flow experimental data revealed a complex relationship between the control parameters and the pulsation response. For each test, the average mass flow rates of the waste water, water lost through the seals, and injector mass flow rates are measured. A dynamic pressure transducer at the pulsator exit measures and records the pressure waveform. Pulsation magnitude, reliability, repeatability, pulsation effects, and detailed variable control are examined. The data shows the pulsator is capable of generating 30% pulsation at 1575 Hz input. The repeatability of the pulsator is questionable because the standard deviations exceeded 40% of the average. The detailed data obtained during this research provides is sufficient to develop a pulsator tuning procedure for future applications.

  5. Theory of unidirectional spin heat conveyer

    SciTech Connect

    Adachi, Hiroto Maekawa, Sadamichi

    2015-05-07

    We theoretically investigate the unidirectional spin heat conveyer effect recently reported in the literature that emerges from the Damon-Eshbach spin wave on the surface of a magnetic material. We develop a simple phenomenological theory for heat transfer dynamics in a coupled system of phonons and the Damon-Eshbach spin wave, and demonstrate that there arises a direction-selective heat flow as a result of the competition between an isotropic heat diffusion by phonons and a unidirectional heat drift by the spin wave. The phenomenological approach can account for the asymmetric local temperature distribution observed in the experiment.

  6. Pulsating White Dwarf Star GD99

    NASA Astrophysics Data System (ADS)

    Chynoweth, K. M.; Thompson, S.; Mullally, F.; Yeates, C.

    2004-12-01

    We present 15 hours of time-series photometry of the variable white dwarf star GD99. These data were obtained at the McDonald Observatory 2.1m Otto Struve Telescope in January 2003, using the Argos CCD photometer. We achieved a noise level as low as 0.07 %, as measured from the power spectrum of our first night. Our observations confirm that GD99 is a unique pulsating white dwarf whose modes show characteristics of both the hot and cold type of DA variable stars. Additionally, GD99 has a large number of modes, making it a good candidate for asteroseismological study. Our preliminary results indicate that this star merits further study to decipher its abundant set of unusual modes. With such a rich period structure, longer continuous data sets will be required to fully resolve the pulsation spectrum.

  7. Underground storage tanks soft waste dislodging and conveyance

    SciTech Connect

    Wellner, A.F.

    1993-10-01

    Currently 140 million liters (37 million gallons) of waste are stored in the single shell underground storage tanks (SSTs) at Hanford. The wastes contain both hazardous and radioactive constituents. This paper focuses on the Westinghouse Hanford Company`s testing program for soft waste dislodging and conveyance technology. This program was initialized to investigate methods of dislodging and conveying soft waste. The main focus was on using air jets, water jets, and/or mechanical blades to dislodge the waste and air conveyance to convey the dislodged waste. These waste dislodging and conveyance technologies would be used in conjunction with a manipulator based retrieval system.

  8. Location of Decimetric Pulsations in Solar Flares

    NASA Astrophysics Data System (ADS)

    Benz, Arnold O.; Battaglia, Marina; Vilmer, Nicole

    This work investigates the spatial relation between coronal X-ray sources and coherent radio emissions, both generally thought to be signatures of particle acceleration. Two limb events were selected during which the radio emission was well correlated in time with hard X-rays. The radio emissions were of the type of decimetric pulsations as determined from the spectrogram observed by Phoenix-2 of ETH Zurich. The radio positions were measured from observations with the Nançay Radioheliograph between 236 and 432 MHz and compared to the position of the coronal X-ray source imaged with RHESSI. The radio pulsations originated at least 30 - 240 Mm above the coronal hard X-ray source. The altitude of the radio emission increases generally with lower frequency. The average positions at different frequencies are on a line pointing approximately to the coronal hard X-ray source. Thus, the pulsations cannot be caused by electrons trapped in the flare loops, but are consistent with emission from a current sheet above the coronal source.

  9. Location of Decimetric Pulsations in Solar Flares

    NASA Astrophysics Data System (ADS)

    Benz, Arnold O.; Battaglia, Marina; Vilmer, Nicole

    2011-11-01

    This work investigates the spatial relation between coronal X-ray sources and coherent radio emissions, both generally thought to be signatures of particle acceleration. Two limb events were selected during which the radio emission was well correlated in time with hard X-rays. The radio emissions were of the type of decimetric pulsations as determined from the spectrogram observed by Phoenix-2 of ETH Zurich. The radio positions were measured from observations with the Nançay Radioheliograph between 236 and 432 MHz and compared to the position of the coronal X-ray source imaged with RHESSI. The radio pulsations originated at least 30 - 240 Mm above the coronal hard X-ray source. The altitude of the radio emission increases generally with lower frequency. The average positions at different frequencies are on a line pointing approximately to the coronal hard X-ray source. Thus, the pulsations cannot be caused by electrons trapped in the flare loops, but are consistent with emission from a current sheet above the coronal source.

  10. DISCOVERY OF AN ULTRAMASSIVE PULSATING WHITE DWARF

    SciTech Connect

    Hermes, J. J.; Castanheira, Barbara G.; Winget, D. E.; Montgomery, M. H.; Harrold, Samuel T.; Kepler, S. O.; Gianninas, A.; Brown, Warren R.

    2013-07-01

    We announce the discovery of the most massive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12, 030 {+-} 210 K WD with a log g =9.08 {+-} 0.06, which corresponds to a mass of 1.20 {+-} 0.03 M{sub Sun }. Stellar evolution models indicate that the progenitor of such a high-mass WD endured a stable carbon-burning phase, producing an oxygen-neon-core WD. The discovery of pulsations in GD 518 thus offers the first opportunity to probe the interior of a WD with a possible oxygen-neon core. Such a massive WD should also be significantly crystallized at this temperature. The star exhibits multi-periodic luminosity variations at timescales ranging from roughly 425 to 595 s and amplitudes up to 0.7%, consistent in period and amplitude with the observed variability of typical ZZ Ceti stars, which exhibit non-radial g-mode pulsations driven by a hydrogen partial ionization zone. Successfully unraveling both the total mass and core composition of GD 518 provides a unique opportunity to investigate intermediate-mass stellar evolution, and can possibly place an upper limit to the mass of a carbon-oxygen-core WD, which in turn constrains Type Ia supernovae progenitor systems.

  11. Conveying Movement in Music and Prosody

    PubMed Central

    Hedger, Stephen C.; Nusbaum, Howard C.; Hoeckner, Berthold

    2013-01-01

    We investigated whether acoustic variation of musical properties can analogically convey descriptive information about an object. Specifically, we tested whether information from the temporal structure in music interacts with perception of a visual image to form an analog perceptual representation as a natural part of music perception. In Experiment 1, listeners heard music with an accelerating or decelerating temporal pattern, and then saw a picture of a still or moving object and decided whether it was animate or inanimate – a task unrelated to the patterning of the music. Object classification was faster when musical motion matched visually depicted motion. In Experiment 2, participants heard spoken sentences that were accompanied by accelerating or decelerating music, and then were presented with a picture of a still or moving object. When motion information in the music matched motion information in the picture, participants were similarly faster to respond. Fast and slow temporal patterns without acceleration and deceleration, however, did not make participants faster when they saw a picture depicting congruent motion information (Experiment 3), suggesting that understanding temporal structure information in music may depend on specific metaphors about motion in music. Taken together, these results suggest that visuo-spatial referential information can be analogically conveyed and represented by music and can be integrated with speech or influence the understanding of speech. PMID:24146920

  12. Conveying movement in music and prosody.

    PubMed

    Hedger, Stephen C; Nusbaum, Howard C; Hoeckner, Berthold

    2013-01-01

    We investigated whether acoustic variation of musical properties can analogically convey descriptive information about an object. Specifically, we tested whether information from the temporal structure in music interacts with perception of a visual image to form an analog perceptual representation as a natural part of music perception. In Experiment 1, listeners heard music with an accelerating or decelerating temporal pattern, and then saw a picture of a still or moving object and decided whether it was animate or inanimate--a task unrelated to the patterning of the music. Object classification was faster when musical motion matched visually depicted motion. In Experiment 2, participants heard spoken sentences that were accompanied by accelerating or decelerating music, and then were presented with a picture of a still or moving object. When motion information in the music matched motion information in the picture, participants were similarly faster to respond. Fast and slow temporal patterns without acceleration and deceleration, however, did not make participants faster when they saw a picture depicting congruent motion information (Experiment 3), suggesting that understanding temporal structure information in music may depend on specific metaphors about motion in music. Taken together, these results suggest that visuo-spatial referential information can be analogically conveyed and represented by music and can be integrated with speech or influence the understanding of speech.

  13. Radial pulsation stability as a function of hydrogen abundance

    NASA Astrophysics Data System (ADS)

    Jeffery, Simon; Saio, Hideyuki

    2015-08-01

    Following the discovery of pulsation in an extremely low-mass pre-white dwarf by Maxted et al. (2011, 2013), Jeffery & Saio (2013) showed that pulsations in such stars would be excited in high radial overtones provided that the driving zone was sufficiently depleted in hydrogen. Following previous work which shows that pulsations are more easily excited in stars where the damping effects of hydrogen are somehow reduced (Jeffery & Saio 2006), we have completed a survey of radial pulsation stability across a substantially larger parameter space. The object is to identify new regions of the HR diagram where stars should be unstable to radial pulsations, or where closely related p-modes might be excited. These would enable targeted surveys for new classes of pulsating variable. This poster reports the survey results and the identification of new instability regions.

  14. Insulated pipe clamp design

    SciTech Connect

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized.

  15. Flexible ocean upwelling pipe

    DOEpatents

    Person, Abraham

    1980-01-01

    In an ocean thermal energy conversion facility, a cold water riser pipe is releasably supported at its upper end by the hull of the floating facility. The pipe is substantially vertical and has its lower end far below the hull above the ocean floor. The pipe is defined essentially entirely of a material which has a modulus of elasticity substantially less than that of steel, e.g., high density polyethylene, so that the pipe is flexible and compliant to rather than resistant to applied bending moments. The position of the lower end of the pipe relative to the hull is stabilized by a weight suspended below the lower end of the pipe on a flexible line. The pipe, apart from the weight, is positively buoyant. If support of the upper end of the pipe is released, the pipe sinks to the ocean floor, but is not damaged as the length of the line between the pipe and the weight is sufficient to allow the buoyant pipe to come to a stop within the line length after the weight contacts the ocean floor, and thereafter to float submerged above the ocean floor while moored to the ocean floor by the weight. The upper end of the pipe, while supported by the hull, communicates to a sump in the hull in which the water level is maintained below the ambient water level. The sump volume is sufficient to keep the pipe full during heaving of the hull, thereby preventing collapse of the pipe.

  16. On the pulsation and evolutionary properties of helium burning radially pulsating variables

    NASA Astrophysics Data System (ADS)

    Bono, G.; Pietrinferni, A.; Marconi, M.; Braga, V. F.; Fiorentino, G.; Stetson, P. B.; Buonanno, R.; Castellani, M.; Dall'Ora, M.; Fabrizio, M.; Ferraro, I.; Giuffrida, G.; Iannicola, G.; Marengo, M.; Magurno, D.; Martinez-Vazquez, C. E.; Matsunaga, N.; Monelli, M.; Neeley, J.; Rastello, S.; Salaris, M.; Short, L.; Stellingwerf, R. F.

    2016-05-01

    We discuss pulsation and evolutionary properties of low- (RR Lyrae, Type II Cepheids) and intermediate-mass (Anomalous Cepheids) radial variables. We focus our attention on the topology of the instability strip and the distribution of the quoted variables in the Hertzsprung-Russell diagram. We discuss their evolutionary status and the dependence on the metallicity. Moreover, we address the diagnostics (period derivative, difference in luminosity, stellar mass) that can provide solid constraints on their progenitors and on the role that binarity and environment have in shaping their current pulsation characteristics. Finally, we briefly outline their use as standard candles.

  17. Large-Scale Aspects and Temporal Evolution of Pulsating Aurora

    NASA Technical Reports Server (NTRS)

    Jones, S. L.; Lessard, M. R.; Rychert, K.; Spanswick, E.; Donovan, E.

    2010-01-01

    Pulsating aurora is a common phenomenon generally believed to occur mainly in the aftermath of a, substorm, where dim long-period pulsating patches appear. The study determines the temporal and spatial evolution of pulsating events using two THEN IIIS ASI stations, at Gillam (66.18 mlat, 332.78 mlon, magnetic midnight at 0634 UT) and Fort Smith, (67.38 mlat, 306.64 mlon, magnetic midnight at, 0806 UT) along roughly the same invariant latitude. Parameters have been calculated from a database of 74 pulsating aurora events from 119 days of good optical data within the period from September 2007 through March 2008 as identified with the Gillam camera. It is shown that the source region of pulsating aurora drifts or expands eastward, away from magnetic midnight, for pre-midnight onsets and that the spatial evolution is more complicated for post midnight onsets, which has implications for the source mechanism. The most probable duration of a pulsating aurora event is roughly 1.5 hours while the distribution of possible event durations includes many long (several hours) events. This may suggest that pulsating aurora is not strictly a substorm recovery phase phenomenon but rather a persistent, long-lived phenomenon that may be temporarily disrupted by auroral substorms. Observations from the Gillam station show that in fact, pulsating aurora is quite common with the occurrence rate increasing to around 60% for morning hours, with 6910 of pulsating aurora onsets occurring after substorm breakup.

  18. DRIVING G-MODE PULSATIONS IN GAMMA DORADUS VARIABLES

    SciTech Connect

    J. GUZIK; A. KAYE; ET AL

    2000-10-10

    The {gamma} Doradus stars are a newly-discovered class of gravity-mode pulsators which lie just at or beyond the red edge of the {delta} Scuti instability strip. We present the results of calculations which predict pulsation instability of high-order g-modes with periods between 0.4 and 3 days, as observed in these stars. The pulsations are driven by the modulation of radiative flux by convection at the base of a deep envelope convection zone. Pulsation instability is predicted only for models with temperatures at the convection zone base between {approximately}200,000 and {approximately}480,000 K. The estimated shear dissipation due to turbulent viscosity within the convection zone, or in an overshoot region below the convection zone, can be comparable to or even exceed the predicted driving, and is likely to reduce the number of unstable modes, or possibly to quench the instability. Additional refinements in the pulsation modeling are required to determine the outcome. A few Doradus stars have been observed that also pulsate in {delta} Scuti-type p-modes, and at least two others have been identified as chemically peculiar. Since our calculated driving region is relatively deep, Doradus pulsations are not necessarily incompatible with surface abundance peculiarities or with {delta} Scuti p-mode pulsations driven by the H and He-ionization {kappa} effect. Such stars will provide useful observational constraints on the proposed Doradus pulsation mechanism.

  19. Reusable pipe flange covers

    DOEpatents

    Holden, James Elliott; Perez, Julieta

    2001-01-01

    A molded, flexible pipe flange cover for temporarily covering a pipe flange and a pipe opening includes a substantially round center portion having a peripheral skirt portion depending from the center portion, the center portion adapted to engage a front side of the pipe flange and to seal the pipe opening. The peripheral skirt portion is formed to include a plurality of circumferentially spaced tabs, wherein free ends of the flexible tabs are formed with respective through passages adapted to receive a drawstring for pulling the tabs together on a back side of the pipe flange.

  20. Study on blood flow pulsation using laser speckle contrast imaging

    NASA Astrophysics Data System (ADS)

    Yuan, Shuai; Chen, Yu; Preza, Chrysanthe; Tang, Cha-Min

    2011-03-01

    Laser speckle contrast imaging (LSCI) is becoming an established method for full-field imaging of blood flow dynamics in animal models. Blood flow pulsation originated from heart beat affects blood flow measurement results of LSCI and it is considered as major physiology noise source for most biomedical applications. But in some biomedical applications, the details of the pulsation process might provide useful information for disease diagnostics. In this study, we investigated the ability as well as the limitation of LSCI in monitoring flow pulsation in phantom study. Both intralipid (2% - 5%) and human whole blood samples are used in phantom study. A syringe pump is controlled by a computer-programmable motor controller and liquid phantom is pushed through a 400 μm ID capillary tube by the pump at different pulsation patterns, varied in frequency (1-7 Hz), valley-to-peak ratio (10%-50%), acceleration/deceleration rate, etc. Speckle contrast images are acquired at 15-30 frames-per-seconds. Our results show: (1) it is very hard for LSCI to pick up signals from high frequency pulsation (5-7 Hz), which is close to the heart back frequency of rats. This might be caused by the nature of fluid dynamics of blood during pulsation. LSCI might not work well for animal models in detecting pulsation. (2) With low frequency pulsation (1 Hz, close to human normal pulsation rate), our experimental results shows from most pulsation patterns, LSCI could catch the fine details of the blood flow change in a cycle. LSCI might be used for studying human blood flow pulsation.

  1. Construction of Database for Pulsating Variable Stars

    NASA Astrophysics Data System (ADS)

    Chen, B. Q.; Yang, M.; Jiang, B. W.

    2011-07-01

    A database for the pulsating variable stars is constructed for Chinese astronomers to study the variable stars conveniently. The database includes about 230000 variable stars in the Galactic bulge, LMC and SMC observed by the MACHO (MAssive Compact Halo Objects) and OGLE (Optical Gravitational Lensing Experiment) projects at present. The software used for the construction is LAMP, i.e., Linux+Apache+MySQL+PHP. A web page is provided to search the photometric data and the light curve in the database through the right ascension and declination of the object. More data will be incorporated into the database.

  2. Ultraviolet Pulsations from X-Ray Pulsars

    NASA Astrophysics Data System (ADS)

    Bless, Robert

    1991-07-01

    We propose to obtain high-speed photometry at ultraviolet wavelengths of all the pulsing X-ray heated stellar atmospheres of the companion stars to the neutron stars in the binaries and to create list of X-ray pulsars with optical pulsations that can be further observed for such purposes as determining the mass ratios of the binary system. Revision History: Prepared for future cycles submission-- BJW 4/24/92; Cycle 3 to cycle 2; PRISM to SINGLE-- BJW 8/27/92;

  3. Optical multichannel sensing of skin blood pulsations

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis; Erts, Renars; Kukulis, Indulis; Ozols, Maris; Prieditis, Karlis

    2004-09-01

    Time resolved detection and analysis of the skin back-scattered optical signals (reflection photoplethysmography or PPG) provide information on skin blood volume pulsations and can serve for cardiovascular assessment. The multi-channel PPG concept has been developed and clinically verified in this study. Portable two- and four-channel PPG monitoring devices have been designed for real-time data acquisition and processing. The multi-channel devices were successfully applied for cardiovascular fitness tests and for early detection of arterial occlusions in extremities. The optically measured heartbeat pulse wave propagation made possible to estimate relative arterial resistances for numerous patients and healthy volunteers.

  4. Pipe-to-pipe impact program

    SciTech Connect

    Alzheimer, J.M.; Bampton, M.C.C.; Friley, J.R.; Simonen, F.A.

    1984-06-01

    This report documents the tests and analyses performed as part of the Pipe-to-Pipe Impact (PTPI) Program at the Pacific Northwest Laboratory. This work was performed to assist the NRC in making licensing decisions regarding pipe-to-pipe impact events following postulated breaks in high energy fluid system piping. The report scope encompasses work conducted from the program's start through the completion of the initial hot oil tests. The test equipment, procedures, and results are described, as are analytic studies of failure potential and data correlation. Because the PTPI Program is only partially completed, the total significance of the current test results cannot yet be accurately assessed. Therefore, although trends in the data are discussed, final conclusions and recommendations will be possible only after the completion of the program, which is scheduled to end in FY 1984.

  5. Heat pipes. [technology utilization

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The development and use of heat pipes are described, including space requirements and contributions. Controllable heat pipes, and designs for automatically maintaining a selected constant temperature, are discussed which would add to the versatility and usefulness of heat pipes in industrial processing, manufacture of integrated circuits, and in temperature stabilization of electronics.

  6. Transient modeling of the thermohydraulic behavior of high temperature heat pipes for space reactor applications

    NASA Technical Reports Server (NTRS)

    Hall, Michael L.; Doster, Joseph M.

    1986-01-01

    Many proposed space reactor designs employ heat pipes as a means of conveying heat. Previous researchers have been concerned with steady state operation, but the transient operation is of interest in space reactor applications due to the necessity of remote startup and shutdown. A model is being developed to study the dynamic behavior of high temperature heat pipes during startup, shutdown and normal operation under space environments. Model development and preliminary results for a hypothetical design of the system are presented.

  7. GW Lib: a Unique Laboratory for White Dwarf Pulsations

    NASA Astrophysics Data System (ADS)

    Toloza, Odette; Gänsicke, Boris T.; Hermes, JJ; Townsley, Dean M.; Szkody, Paula; Beuermann, K.; Bildsten, Lars; de Martino, D.; Godon, Patrick; Henden, Arne A.; Hubeny, Ivan; Knigge, Christian; Long, Knox S.; Marsh, T. R.; Patterson, Joseph; Schreiber, M. R.; Sion, Edward M.; Zorotovic, Monica

    2015-06-01

    Non-radial pulsations have been identified in a number of accreting white dwarfs in cataclysmic variables. These stars offer insight into the excitation of pulsation modes in mixed H/He/Z atmospheres, and the response of these modes to changes in the white dwarf temperature. Among all pulsating cataclysmic variable white dwarfs, GW Lib stands out by having a well-established observational record of three independent pulsation modes that were wiped out during its 2007 outburst. We have obtained new HST ultraviolet observations in May 2013 that show an unexpected behaviour: besides some activity near the ˜280 s period that has been observed in the past, the white dwarf underwent a large-amplitude brightening. We demonstrate that the brightening is related to an increase of the photospheric temperature, argue against an accretion episode as explanation, and discuss this event in the context of non-radial pulsations on a rapidly rotating star.

  8. Statistical properties of geomagnetic pulsations at the Observatory of Fuerstenfeldbruck determined with the aid of pulsation indices. Part 2: Periodicity in the occurrence of pulsations

    NASA Astrophysics Data System (ADS)

    Strestik, J.

    The records of the Furstenfeldbrock observatory (FRG) for the years of 1960-1971 were processed using the method of pulsation indices, based on the mean diurnal amplitude of the pulsations in the frequency ranges Pc2, Pc3, Pc4 and Pc5. The variation in the occurrence of pulsations in the course of the solar cycle, the seasonal variational variation and the periods associated with the Sun's rotation were studied for pulsations in all frequency ranges and in both horizontal components. Long-term variations were determined for calm as well as disturbed days. The changes of periodicities in the course of the solar cycle were investigated. The ratio of the intensities of the annual and the semi-annual variations, as well as the ratio of the intensities of the 27-day variation and of variations with shorter periods were studied. The periodicities were determined with the aid of power spectra and expressed graphically.

  9. BNL piping research

    SciTech Connect

    Bezler, P.; Subudhi, M.; Wang, Y.K.; Shteyngart, S.

    1985-01-01

    Brookhaven National Laboratory (BNL) has assisted in the development of methods to evaluate the analysis methods used by industry to qualify nuclear power piping. Through FY 1985 these efforts were conducted under the Mechanical Piping Benchmarks project while current and future efforts will be performed under the Combination Procedures for piping project. Under these projects BNL has developed analytical benchmark problems for piping systems evaluated using uniform or independent support motion response spectrum methods, investigated the adequacy and limitations of linear piping analysis methods by comparison to test results and evaluated and developed criteria for new and alternate methods of analysis. A summary description of the status of these efforts is provided.

  10. Pipe Line Control

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The array of tanks, pipes and valves in the photo below is a petroleum tank farm in Georgia, part of a petrochemical pipe line system that moves refined petroleum products from Texas and Louisiana to the mid-Eastern seaboard. The same pipes handle a number of different products, such as gasoline, kerosene, jet fuel or fuel oil. The fluids are temporarily stored in tanks, pumped into the pipes in turn and routed to other way stations along the pipe line. The complex job of controlling, measuring and monitoring fuel flow is accomplished automatically by a computerized control and communications system which incorporates multiple space technologies.

  11. Determination of discharge during pulsating flow

    USGS Publications Warehouse

    Thompson, T.H.

    1968-01-01

    Pulsating flow in an open channel is a manifestation of unstable-flow conditions in which a series of translatory waves of perceptible magnitude develops and moves rapidly downstream. Pulsating flow is a matter of concern in the design and operation of steep-gradient channels. If it should occur at high stages in a channel designed for stable flow, the capacity of the channel may be inadequate at a discharge that is much smaller than that for which the channel was designed. If the overriding translatory wave carries an appreciable part of the total flow, conventional stream-gaging procedures cannot be used to determine the discharge; neither the conventional instrumentation nor conventional methodology is adequate. A method of determining the discharge during pulsating flow was tested in the Santa Anita Wash flood control channel in Arcadia, Calif., April 16, 1965. Observations of the dimensions and velocities of translatory waves were made during a period of controlled reservoir releases of about 100, 200, and 300 cfs (cubic feet per second). The method of computing discharge was based on (1) computation of the discharge in the overriding waves and (2) computation of the discharge in the shallow-depth, or overrun, part of the flow. Satisfactory results were obtained by this method. However, the procedure used-separating the flow into two components and then treating the shallow-depth component as though it were steady--has no theoretical basis. It is simply an expedient for use until laboratory investigation can provide a satisfactory analytical solution to the problem of computing discharge during pulsating flow. Sixteen months prior to the test in Santa Anita Wash, a robot camera had been designed .and programmed to obtain the data needed to compute discharge by the method described above. The photographic equipment had been installed in Haines Creek flood control channel in Los Angeles, Calif., but it had not been completely tested because of the infrequency of

  12. Impedance modelling of pipes

    NASA Astrophysics Data System (ADS)

    Creasy, M. Austin

    2016-03-01

    Impedance models of pipes can be used to estimate resonant frequencies of standing waves and model acoustic pressure of closed and open ended pipes. Modelling a pipe with impedance methods allows additional variations to the pipe to be included in the overall model as a system. Therefore an actuator can be attached and used to drive the system and the impedance model is able to include the dynamics of the actuator. Exciting the pipe system with a chirp signal allows resonant frequencies to be measured in both the time and frequency domain. The measurements in the time domain are beneficial for introducing undergraduates to resonances without needing an understanding of fast Fourier transforms. This paper also discusses resonant frequencies in open ended pipes and how numerous texts incorrectly approximate the resonant frequencies for this specific pipe system.

  13. An experimental study on an oscillating loop heat pipe consisting of three interconnected columns

    NASA Astrophysics Data System (ADS)

    Özdemir, Mustafa

    2007-04-01

    This paper presents some experimental results of an extensive research on a novel oscillating heat pipe. The heat pipe is formed of three interconnected columns as different from the pulsating heat pipe designs. The dimensions of the heat pipe considered in this study are large enough to neglect the effect of capillary forces. Thus, the self-oscillation of the system is driven by the gravitational force and the phase lag between the evaporation and condensation processes. The overall heat transfer coefficient is found to be approximately constant irrespective of heat load for the experimental cases considered. The results are also compared with the previously published data by other investigators for water as the working fluid and for the same heat input range. The experimental data for the time variation of the liquid column heights and the vapor pressure are correlated algebraically, convenient for practical uses.

  14. 30 CFR 56.19068 - Orderly conduct in conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Orderly conduct in conveyances. 56.19068 Section 56.19068 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 56.19068 Orderly conduct in conveyances. Persons shall enter, ride,...

  15. 30 CFR 57.19068 - Orderly conduct in conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Orderly conduct in conveyances. 57.19068 Section 57.19068 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoisting Procedures § 57.19068 Orderly conduct in conveyances. Persons shall enter, ride,...

  16. Pneumatic Conveying of Seed Cotton: Minimum Velocity and Pressure Drop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electricity is major cost for cotton gins, representing approximately 20% of the industry’s variable costs. Fans used for pneumatic conveying consume the majority of electricity at cotton gins. Development of control systems to reduce the air velocity used for conveying seed cotton could significant...

  17. Pneumatic Conveying of Seed Cotton: Minimum Velocity and Pressure Drop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electricity is a major cost for cotton gins, representing approximately 20% of variable costs. Fans used for pneumatic conveying consume the majority of electricity at cotton gins. Development of control systems to reduce the air velocity used for conveying seed cotton could significantly decrease e...

  18. 30 CFR 56.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Conveying explosives by hand. 56.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6205 Conveying explosives by hand. Closed, nonconductive containers shall be used to...

  19. 30 CFR 57.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Conveying explosives by hand. 57.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6205 Conveying explosives by hand. Closed, nonconductive...

  20. 30 CFR 56.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Conveying explosives by hand. 56.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6205 Conveying explosives by hand. Closed, nonconductive containers shall be used to...

  1. 30 CFR 56.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Conveying explosives by hand. 56.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6205 Conveying explosives by hand. Closed, nonconductive containers shall be used to...

  2. 30 CFR 56.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveying explosives by hand. 56.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6205 Conveying explosives by hand. Closed, nonconductive containers shall be used to...

  3. 30 CFR 56.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Conveying explosives by hand. 56.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6205 Conveying explosives by hand. Closed, nonconductive containers shall be used to...

  4. 30 CFR 57.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Conveying explosives by hand. 57.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6205 Conveying explosives by hand. Closed, nonconductive...

  5. 30 CFR 57.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Conveying explosives by hand. 57.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6205 Conveying explosives by hand. Closed, nonconductive...

  6. 30 CFR 57.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveying explosives by hand. 57.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6205 Conveying explosives by hand. Closed, nonconductive...

  7. 30 CFR 57.6205 - Conveying explosives by hand.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Conveying explosives by hand. 57.6205 Section... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6205 Conveying explosives by hand. Closed, nonconductive...

  8. 21 CFR 1240.90 - Approval of treatment aboard conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COMMUNICABLE DISEASES Source and Use of Potable Water § 1240.90 Approval of treatment aboard conveyances. (a) The treatment of water aboard conveyances shall be approved by the Commissioner of Food and Drugs if... produce, potable water. (b) The Commissioner of Food and Drugs may base his approval or disapproval of...

  9. 9 CFR 88.3 - Standards for conveyances.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION OF EQUINES FOR SLAUGHTER § 88.3 Standards for conveyances. (a) The animal cargo space of..., and maintained in a manner that at all times protects the health and well-being of the equines being... conveyance that has the animal cargo space divided into two or more stacked levels, except that...

  10. 19 CFR 148.45 - Vehicles and other conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Vehicles and other conveyances. 148.45 Section 148.45 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF... Vehicles and other conveyances. Nonresidents are entitled to entry free of duty and internal revenue...

  11. 19 CFR 162.22 - Seizure of conveyances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Seizure of conveyances. 162.22 Section 162.22 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Seizures § 162.22 Seizure of conveyances. (a)...

  12. 21 CFR 1240.90 - Approval of treatment aboard conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... health authorities of contiguous foreign nations. (c) Overboard water treated on vessels shall be from... COMMUNICABLE DISEASES Source and Use of Potable Water § 1240.90 Approval of treatment aboard conveyances. (a) The treatment of water aboard conveyances shall be approved by the Commissioner of Food and Drugs...

  13. 32 CFR 644.439 - Sale and conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Sale and conveyance. 644.439 Section 644.439... ESTATE HANDBOOK Disposal Disposal of Fee-Owned Real Property and Easement Interests § 644.439 Sale and conveyance. Sales procedure, including advertising, will be in accordance with §§ 644.540 through...

  14. 43 CFR 2653.8-1 - Acreage to be conveyed.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Acreage to be conveyed. 2653.8-1 Section... Selections § 2653.8-1 Acreage to be conveyed. A Native may secure title to the surface estate of only a single tract not to exceed 160 acres under the provisions of this subpart, and shall be limited to...

  15. 43 CFR 2653.8-1 - Acreage to be conveyed.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Acreage to be conveyed. 2653.8-1 Section... Selections § 2653.8-1 Acreage to be conveyed. A Native may secure title to the surface estate of only a single tract not to exceed 160 acres under the provisions of this subpart, and shall be limited to...

  16. 43 CFR 2653.8-1 - Acreage to be conveyed.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Acreage to be conveyed. 2653.8-1 Section... Selections § 2653.8-1 Acreage to be conveyed. A Native may secure title to the surface estate of only a single tract not to exceed 160 acres under the provisions of this subpart, and shall be limited to...

  17. 43 CFR 2653.8-1 - Acreage to be conveyed.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Acreage to be conveyed. 2653.8-1 Section... Selections § 2653.8-1 Acreage to be conveyed. A Native may secure title to the surface estate of only a single tract not to exceed 160 acres under the provisions of this subpart, and shall be limited to...

  18. Methods of conveying fluids and methods of sublimating solid particles

    DOEpatents

    Turner, Terry D; Wilding, Bruce M

    2013-10-01

    A heat exchanger and associated methods for sublimating solid particles therein, for conveying fluids therethrough, or both. The heat exchanger includes a chamber and a porous member having a porous wall having pores in communication with the chamber and with an interior of the porous member. A first fluid is conveyed into the porous member while a second fluid is conveyed into the porous member through the porous wall. The second fluid may form a positive flow boundary layer along the porous wall to reduce or eliminate substantial contact between the first fluid and the interior of the porous wall. The combined first and second fluids are conveyed out of the porous member. Additionally, the first fluid and the second fluid may each be conveyed into the porous member at different temperatures and may exit the porous member at substantially the same temperature.

  19. Low Reynolds number multiple-time-scale turbulence model and calculations of steady and pulsating shear layers

    NASA Technical Reports Server (NTRS)

    Kim, Sang-Wook

    1992-01-01

    A low Reynolds number multiple-time-scale turbulence model (LMS) and its application to fully developed turbulent channel flows and pulsating pipe flows are presented. The LMS can describe the inequilibrium turbulence phenomena down to the viscous sublayer. The calculated fluid flow and turbulence fields for the channel flows are in better agreement with the direct numerical simulation (DNS) results than those obtained using a Reynolds stress turbulence model, and the calculated near-wall dissipation rates are in qualitatively correct agreement with the DNS results. The LMS also successfully predicts the rapidly varying phase-lead of the wall shearing stress that occurs in a narrow range of the dimensionless frequency omega (+) = (omega x nu)/(upsilon x tau(exp2)) for the pulsating pipe flows while various other turbulence models fail to predict this phenomenon, and the LMS yields significantly improved numerical results for a wide range of the dimensionless frequency compared with those obtained using a rapid distortion theory (RDT).

  20. Conveying Global Circulation Patterns in HDTV

    NASA Astrophysics Data System (ADS)

    Gardiner, N.; Janowiak, J.; Kinzler, R.; Trakinski, V.

    2006-12-01

    The American Museum of Natural History has partnered with the National Centers for Environmental Prediction (NCEP) to educate general audiences about weather and climate using high definition video broadcasts built from half-hourly global mosaics of infrared (IR) data from five geostationary satellites. The dataset being featured was developed by NCEP to improve precipitation estimates from microwave data that have finer spatial resolution but poorer temporal coverage. The IR data span +/-60 degrees latitude and show circulation patterns at sufficient resolution to teach informal science center visitors about both weather and climate events and concepts. Design and editorial principles for this media program have been guided by lessons learned from production and annual updates of visualizations that cover eight themes in both biological and Earth system sciences. Two formative evaluations on two dates, including interviews and written surveys of 480 museum visitors ranging in age from 13 to over 60, helped refine the design and implementation of the weather and climate program and demonstrated that viewers understood the program's initial literacy objectives, including: (1) conveying the passage of time and currency of visualized data; (2) geographic relationships inherent to atmospheric circulation patterns; and (3) the authenticity of visualized data, i.e., their origin from earth-orbiting satellites. Surveys also indicated an interest and willingness to learn more about weather and climate principles and events. Expanded literacy goals guide ongoing, biweekly production and distribution of global cloud visualization pieces that reach combined audiences of approximately 10 million. Two more rounds of evaluation are planned over the next two years to assess the effectiveness of the media program in addressing these expanded literacy goals.

  1. Pulsational Modes of Mira Variables Examined through IR Interferometry

    NASA Astrophysics Data System (ADS)

    Creech-Eakman, M. J.; Thompson, R. R.; van Belle, G. T.

    1999-12-01

    We have undertaken a program with the Palomar Testbed Interferometer (PTI) to measure the angular size variations, with respect to pulsational phase, of a group of about 20 mainly O-rich Mira variables. While previous groups have attempted to measure angular size with phase (van Belle et al. 1996, 1997; Tej et al. 1999) these are the first dedicated, spatially-resolved K band observations designed to detect size variations in a large sample of Miras at regular intervals over their pulsation periods. Our first goal has been the unambiguous detection of the mira pulsational cycle with phase, already shown in previous work to be as much as 35% of the radial size over the course of a pulsational period (van Belle et al. 1996; Burns et al. 1997; Tuthill et al. 1995; Perrin et al. 1999 ). We will ultimately use these data, along with the best estimates of stellar distance and effective temperatures for these sources, to determine the mode of pulsation. There has long been a debate as to whether Mira variables pulsate in their fundamental or first-overtone mode (Barthes 1999; Feast 1998; Wood and Sebo 1996). Determination of the pulsation behavior of Mira variables may eventually render them suitable as standard candles for distance determination.

  2. There and Back Again?: The Disappearing Pulsations of CS 1246

    NASA Astrophysics Data System (ADS)

    Vasquez Soto, Alan; Barlow, Brad

    2016-01-01

    Hot subdwarf stars were once main sequence stars, like the sun, that deviated from normal stellar evolution due to binary interactions and evolved into extreme horizontal branch stars. Several of these stars exhibit rapid pulsations driven by iron opacity instabilities. CS 1246 is a rapidly pulsating hot subdwarf discovered in 2009 that is dominated by a single 371 second pulsation. At the time of its discovery, the pulsational amplitude was one of the largest known, making CS 1246 an ideal candidate for follow up studies. Observations in 2013 implied that the pulsational amplitude had decreased significantly. Since then we have continued monitoring the star using the robotic SKYNET telescopes in Chile, in order to further characterize any changes. Our recent observations show that the pulsational amplitude has gone down by a factor of six: CS 1246 is barely a pulsator anymore. The decay in amplitude over time is reminiscent of a damped harmonic oscillator. Here we present six years of photometry for CS 1246 and discuss possible scenarios that might explain its interesting behavior.

  3. New pulsating casing collar to improve cementing quality

    SciTech Connect

    Chen, P.; He, K.; Wu, J.

    1998-12-31

    This paper presents the design and test results of a new pulsating casing collar which improves cementing quality. The new pulsating casing collar (PCC) is designed according to the Helmholtz oscillator to generate a pulsating jet flow by self-excitation in the cementing process. By placing this new pulsating casing collar at the bottom of casing string, the generated pulsating jet flow transmits vibrating pressure waves up through the annulus and helps remove drilling mud in the annulus. It can therefore improve cementing quality, especially when eccentric annulus exists due to casing eccentricity where the mud is difficult to remove. The new pulsating casing collar consists of a top nozzle, a resonant chamber, and a bottom nozzle. It can be manufactured easily and is easy to use in the field. It has been tested in Jianghan oil-field, P.R. China. The field-test results support the theoretical analysis and laboratory test, and the cementing quality is shown greatly improved by using the new pulsating casing collar.

  4. 65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL ...

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

    65. FIRE SUPPRESSION PIPES BEHIND FLAME BUCKET. PIPES TO UMBILICAL MAST IN LOWER LEFT CORNER; PIPES TO LAUNCHER IN UPPER LEFT CORNER; PIPES TO FLAME BUCKET IN LOWER RIGHT CORNER OF PHOTOGRAPH. POTABLE WATER PIPING IN UPPER RIGHT CORNER OF PHOTO. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  5. A numerical approach for flow-induced vibration of pipe structures

    NASA Astrophysics Data System (ADS)

    Ting, E. C.; Hosseinipour, A.

    1983-06-01

    A structural impedance approach is extended for the dynamic analysis of pipe structures conveying fluid flow. The method is efficient in computation and convenient for studying transient responses. Thus, it is possible to study the transition from a stable condition to an unstable condition of the pipe structure as the flow speed increases. The structure may also exhibit different modes of instability. The present approach predicts the mode without prior assumption. Numerical examples are given for a hanging cantilever and a simply supported pipe. The critical speed associated with the dynamic stability is calculated and compared with available analytical and experimental results.

  6. A Novel Approach to Solve Linearized Stellar Pulsation Equations

    NASA Astrophysics Data System (ADS)

    Bard, Christopher; Teitler, S.

    2011-01-01

    We present a new approach to modeling linearized, non-radial pulsations in differentially rotating, massive stars. As a first step in this direction, we consider adiabatic pulsations and adopt the Cowling approximation that perturbations of the gravitational potential and its radial derivative are negligible. The angular dependence of the pulsation modes is expressed as a series expansion of associated Legendre polynomials; the resulting coupled system of differential equations is then solved by finding the eigenfrequencies at which the determinant of a characteristic matrix vanishes. Our method improves on previous treatments by removing the requirement that an arbitrary normalization be applied to the eigenfunctions; this brings the benefit of improved numerical robustness.

  7. White dwarf evolution - Cradle-to-grave constraints via pulsation

    NASA Technical Reports Server (NTRS)

    Kawaler, Steven D.

    1990-01-01

    White dwarf evolution, particularly in the early phases, is not very strongly constrained by observation. Fortunately, white dwarfs undergo nonradial pulsation in three distinct regions of the H-R diagram. These pulsations provide accurate masses, surface compositional structure and rotation velocities, and help constrain other important physical properties. We demonstrate the application of the tools of stellar seismology to white dwarf evolution using the hot white dwarf star PG 1159-035 and the cool DAV (or ZZ Ceti) stars as examples. From pulsation studies, significant challenges to the theory of white dwarf evolution emerge.

  8. Heat transfer coefficients for drying in pulsating flows

    SciTech Connect

    Fraenkel, S.L.

    1998-05-01

    Pulsating flows generated by a Rijke type combustor are studied for drying of grains and food particles. It is assumed that the velocity fluctuations are the main factor in the enhancement of the drying process. The heat transfer coefficients for drying in vibrating beds are utilized to estimate the heat transfer coefficients of fixed beds in pulsating and permeating flows and are compared to the steady flow heat transfer coefficients obtained for solid porous bodies, after perturbing the main flow. The cases considered are compared to the convective heat transfer coefficients employed in non-pulsating drying.

  9. Optical noninvasive monitoring of skin blood pulsations

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis

    2005-04-01

    Time-resolved detection and analysis of skin backscattered optical signals (remission photoplethysmography or PPG) provide rich information on skin blood volume pulsations and can serve for reliable cardiovascular assessment. Single- and multiple-channel PPG concepts are discussed. Simultaneous data flow from several locations on the human body allows us to study heartbeat pulse-wave propagation in real time and to evaluate vascular resistance. Portable single-, dual-, and four-channel PPG monitoring devices with special software have been designed for real-time data acquisition and processing. The prototype devices have been clinically studied, and their potential for monitoring heart arrhythmias, drug-efficiency tests, steady-state cardiovascular assessment, body fitness control, and express diagnostics of the arterial occlusions has been confirmed.

  10. THE PULSATION MODE OF THE CEPHEID POLARIS

    SciTech Connect

    Turner, D. G.; Kovtyukh, V. V.; Usenko, I. A.; Gorlova, N. I.

    2013-01-01

    A previously derived photometric parallax of 10.10 {+-} 0.20 mas, d = 99 {+-} 2 pc, is confirmed for Polaris by a spectroscopic parallax derived using line ratios in high dispersion spectra for the Cepheid. The resulting estimates for the mean luminosity of (M{sub V} ) = -3.07 {+-} 0.01 s.e., average effective temperature of (T{sub eff}) = 6025 {+-} 1 K s.e., and intrinsic color of ((B) - (V)){sub 0} = +0.56 {+-} 0.01 s.e., which match values obtained previously from the photometric parallax for a space reddening of E{sub B-V} = 0.02 {+-} 0.01, are consistent with fundamental mode pulsation for Polaris and a first crossing of the instability strip, as also argued by its rapid rate of period increase. The systematically smaller Hipparcos parallax for Polaris appears discrepant by comparison.

  11. Numerical Modelling of Pulse Combustor Tail Pipe Heat Transfer.

    NASA Astrophysics Data System (ADS)

    Thyageswaran, Sridhar

    1994-01-01

    Computational fluid dynamics analysis was used to perform multi-dimensional simulations of flow in a pulse combustor tail pipe. The tail pipe flow is complicated by periodic reversals amid large rates of turbulent heat transfer. The primary objectives were to understand the mechanisms causing heat transfer enhancement under pulsing flow conditions, and to develop a flow-based model capable of predicting heat transfer rates over a broad range of operating conditions. The experiments of Dec et al. (Combustion and Flame, 77, 80 and 83), in a square cross-section tail pipe, were used as the reference. The research focussed on modelling the near-wall turbulence transport, by treating the tail pipe as a two-dimensional channel. An experimental baseline pulsing case was simulated using the wall-function model, and an alternative near -wall turbulence model known as the Boundary Layer Wall Model. The latter uses an algebraically prescribed wall layer turbulence length scale, and allows much greater phase resolution between the near-wall and the bulk flow. Heat transfer predictions from these quasi-steady models compare poorly with the time-resolved measurements, and fail to match the observed increase in the instantaneous heat transfer during times of flow reversal. An unsteady wall layer model, with a robust prescription for the length scale damping factor, A^ {+}, was developed. Allowing A ^{+} to vary with the wall layer parameter, u^{+}p ^{+}, helps to model the effects of adverse and favourable pressure gradients on the wall layer turbulence during a pulsation cycle. A sequence of lag equations is also used, to incorporate the delayed response of the wall layer turbulence to the time-varying pressure gradient. Simulations of many operating conditions, spanning a range of pulsation frequencies, amplitudes and mean flow Reynolds numbers, indicate that the improved model is capable of capturing the essential trends observed by Dec et al.

  12. Deployable Heat Pipe Radiator

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1975-01-01

    A 1.2- by 1.8-m variable conductance heat pipe radiator was designed, built, and tested. The radiator has deployment capability and can passively control Freon-21 fluid loop temperatures under varying loads and environments. It consists of six grooved variable conductance heat pipes attached to a 0.032-in. aluminum panel. Heat is supplied to the radiator via a fluid header or a single-fluid flexible heat pipe header. The heat pipe header is an artery design that has a flexible section capable of bending up to 90 degrees. Radiator loads as high as 850 watts were successfully tested. Over a load variation of 200 watts, the outlet temperature of the Freon-21 fluid varied by 7 F. An alternate control system was also investigated which used a variable conductance heat pipe header attached to the heat pipe radiator panel.

  13. Dehumidifying Heat Pipe

    NASA Technical Reports Server (NTRS)

    Khattar, Mukesh K.

    1993-01-01

    U-shaped heat pipe partly dehumidifies air leaving air conditioner. Fits readily in air-handling unit of conditioner. Evaporator and condenser sections of heat pipe consist of finned tubes in comb pattern. Each tube sealed at one end and joined to manifold at other. Sections connected by single pipe carrying vapor to condenser manifold and liquid to evaporator manifold. Simple on/off or proportional valve used to control flow of working fluid. Valve actuated by temperature/humidity sensor.

  14. Abrasion resistant heat pipe

    DOEpatents

    Ernst, Donald M.

    1984-10-23

    A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  15. Abrasion resistant heat pipe

    DOEpatents

    Ernst, D.M.

    1984-10-23

    A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  16. A one-dimensional model for gas-solid heat transfer in pneumatic conveying

    NASA Astrophysics Data System (ADS)

    Smajstrla, Kody Wayne

    A one-dimensional ODE model reduced from a two-fluid model of a higher dimensional order is developed to study dilute, two-phase (air and solid particles) flows with heat transfer in a horizontal pneumatic conveying pipe. Instead of using constant air properties (e.g., density, viscosity, thermal conductivity) evaluated at the initial flow temperature and pressure, this model uses an iteration approach to couple the air properties with flow pressure and temperature. Multiple studies comparing the use of constant or variable air density, viscosity, and thermal conductivity are conducted to study the impact of the changing properties to system performance. The results show that the fully constant property calculation will overestimate the results of the fully variable calculation by 11.4%, while the constant density with variable viscosity and thermal conductivity calculation resulted in an 8.7% overestimation, the constant viscosity with variable density and thermal conductivity overestimated by 2.7%, and the constant thermal conductivity with variable density and viscosity calculation resulted in a 1.2% underestimation. These results demonstrate that gas properties varying with gas temperature can have a significant impact on a conveying system and that the varying density accounts for the majority of that impact. The accuracy of the model is also validated by comparing the simulation results to the experimental values found in the literature.

  17. External artery heat pipe

    NASA Technical Reports Server (NTRS)

    Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

    1989-01-01

    An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

  18. Introduction to Heat Pipes

    NASA Technical Reports Server (NTRS)

    Ku, Jentung

    2015-01-01

    This is the presentation file for the short course Introduction to Heat Pipes, to be conducted at the 2015 Thermal Fluids and Analysis Workshop, August 3-7, 2015, Silver Spring, Maryland. NCTS 21070-15. Course Description: This course will present operating principles of the heat pipe with emphases on the underlying physical processes and requirements of pressure and energy balance. Performance characterizations and design considerations of the heat pipe will be highlighted. Guidelines for thermal engineers in the selection of heat pipes as part of the spacecraft thermal control system, testing methodology, and analytical modeling will also be discussed.

  19. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1972-01-01

    The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

  20. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  1. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  2. Heat Pipe Materials Compatibility

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  3. Pipe crawler apparatus

    DOEpatents

    Hovis, Gregory L.; Erickson, Scott A.; Blackmon, Bruce L.

    2002-01-01

    A pipe crawler apparatus particularly useful for 3-inch and 4-inch diameter pipes is provided. The pipe crawler apparatus uses a gripping apparatus in which a free end of a piston rod is modified with a bearing retaining groove. Bearings, placed within the groove, are directed against a camming surface of three respective pivoting support members. The non-pivoting ends of the support members carry a foot-like gripping member that, upon pivoting of the support member, engages the interior wall of the pipe.

  4. Heat Pipe Planets

    NASA Technical Reports Server (NTRS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  5. An investigation of swirl flow field in pneumatic conveying duct

    NASA Astrophysics Data System (ADS)

    Huang, Xijun; Dong, Jinzhong

    1992-10-01

    The swirl flow field of a pneumatic conveying system is investigated experimentally. The swirl is imparted to the flow by the use of swirl vanes. A five-hole probe is used for measuring the tangential angle of flow, axial velocity, static pressure of flow, and swirl number in the flow sections of a conveying system. It is shown that the existence of a central screw conveyer produces the contrary swirl flow under some of the swirl vane angle conditions. The larger axial velocity is produced in the outer annular layer of flow. The maximum value of the swirl number in the flow sections agrees with a simplified theoretical relation.

  6. Photometric study of the pulsating, eclipsing binary OO DRA

    SciTech Connect

    Zhang, X. B.; Deng, L. C.; Tian, J. F.; Wang, K.; Yan, Z. Z.; Luo, C. Q.; Sun, J. J.; Liu, Q. L.; Xin, H. Q.; Zhou, Q.; Luo, Z. Q.

    2014-12-01

    We present a comprehensive photometric study of the pulsating, eclipsing binary OO Dra. Simultaneous B- and V-band photometry of the star was carried out on 14 nights. A revised orbital period and a new ephemeris were derived from the data. The first photometric solution of the binary system and the physical parameters of the component stars are determined. They reveal that OO Dra could be a detached system with a less-massive secondary component nearly filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. A frequency analysis of the residual light yields two confident pulsation modes in both B- and V-band data with the dominant frequency detected at 41.865 c/d. A brief discussion concerning the evolutionary status and the pulsation nature of the binary system is finally given.

  7. Unilateral Loss of Spontaneous Venous Pulsations in an Astronaut

    NASA Technical Reports Server (NTRS)

    Mader, Thomas H.; Gibson, C. Robert; Lee, Andrew G.; Patel, Nimesh; Hart, Steven; Pettit, Donald R.

    2014-01-01

    Spontaneous venous pulsations seen on the optic nerve head (optic disc) are presumed to be caused by fluctuations in the pressure gradient between the intraocular and retrolaminar venous systems. The disappearance of previously documented spontaneous venous pulsations is a well-recognized clinical sign usually associated with a rise in intracranial pressure and a concomitant bilateral elevation of pressure in the subarachnoid space surrounding the optic nerves. In this correspondence we report the unilateral loss of spontaneous venous pulsations in an astronaut 5 months into a long duration space flight. We documented a normal lumbar puncture opening pressure 8 days post mission. The spontaneous venous pulsations were also documented to be absent 21 months following return to Earth.. We hypothesize that these changes may have resulted from a chronic unilateral rise in optic nerve sheath pressure caused by a microgravity-induced optic nerve sheath compartment syndrome.

  8. Pulsations of B stars: A review of observations and theories

    SciTech Connect

    Cox, A.N.

    1986-01-01

    The observational and theoretical status are discussed for several classes of variable B stars. The older classes now seem to be better understood in terms of those stars that probably have at least one radial mode and those that have only nonradial modes. The former are the ..beta.. Cephei variables, and the latter are the slowly rotating 53 Persei and the rapidly rotating zeta Ophiuchi variables. It seems that in this last class there are also some Be stars that show nonradial pulsations from the variations of the line shapes and their light. Among the nonradial pulsators, we must also include the supergiants which show pulsations with very short lifetimes. A review of the present observational and theoretical problems is given. The most persistent problem of the cause for the pulsations is briefly discussed, and many proposed mechanisms plus some new thoughts are presented. 57 refs., 4 figs.

  9. Report of geomagnetic pulsation indices for space weather applications

    USGS Publications Warehouse

    Xu, Z.; Gannon, Jennifer L.; Rigler, Erin J.

    2013-01-01

    The phenomenon of ultra-low frequency geomagnetic pulsations was first observed in the ground-based measurements of the 1859 Carrington Event and has been studied for over 100 years. Pulsation frequency is considered to be “ultra” low when it is lower than the natural frequencies of the plasma, such as the ion gyrofrequency. Ultra-low frequency pulsations are considered a source of noise in some geophysical analysis techniques, such as aeromagnetic surveys and transient electromagnetics, so it is critical to develop near real-time space weather products to monitor these geomagnetic pulsations. The proper spectral analysis of magnetometer data, such as using wavelet analysis techniques, can also be important to Geomagnetically Induced Current risk assessment.

  10. Canards in a rheodynamic model of cardiac pressure pulsations

    NASA Astrophysics Data System (ADS)

    Xie, Feng; Chen, Xian-Feng

    2007-09-01

    This paper reports on the canard phenomenon occurring in a rheodynamic model of cardiac pressure pulsations. By singular perturbation techniques the corresponding parameter value at which canards exist is obtained. The physiological significance of canards in this model is given.

  11. Return of Pulsations in SDSS 0745+4538

    NASA Astrophysics Data System (ADS)

    Mukadam, Anjum S.; Townsley, D. M.; Szkody, P.; Gänsicke, B. T.; Winget, D. E.; Hermes, J. J.; Howell, Steve B.; Teske, J.; Patterson, Joseph; Kemp, Jonathan; Armstrong, Eve

    2010-11-01

    Nonradial pulsations had ceased in the accreting white dwarf SDSS J074531.92+453829.6 subsequent to its October 2006 outburst. We recently acquired optical high-speed time-series photometry on this cataclysmic variable more than three years after its outburst to find that pulsations have now returned to the primary white dwarf. Moreover, the observed pulsation periods agree with pre-outburst periods within the uncertainties of 1-2 s. This discovery is both remarkable and significant because it indicates that the outburst did not affect the interior stellar structure, which dictates the observed pulsation frequencies. Using this discovery in addition to an HST ultra-violet temperature measurement obtained one year after outburst, we have also been able to constrain the matter accreted during the 2006 outburst.

  12. Atomic diffusion and observations of pulsating A stars

    NASA Astrophysics Data System (ADS)

    Kurtz, D. W.

    2013-12-01

    Atomic diffusion - important in many contexts in stellar astrophysics and an important thread running through this meeting - is most spectacularly observable in the atmospheres of some A stars. The magnetic Ap stars and the non-magnetic Am stars show directly abundance anomalies caused by gravitational settling and radiative levitation. Over the last decade spectroscopic studies have begun to provide maps of abundance distributions in the magnetic Ap stars in three dimensions. Interestingly, high radial overtone p-mode pulsations in roAp stars have also given three-dimensional views of the stellar atmospheres with studies of rotational and line profile variations of pulsation amplitudes and phases. These detailed looks at the effects of microscopic atmospheric changes in the strongly non-LTE and magnetic upper atmospheric layers of Ap stars provide perhaps the most exciting challenge to atomic diffusion theory in terms of detailed explanation and prediction. Am stars were at one time thought not to pulsate because of gravitational settling of He from the He ii ionization zone that provides the κ-mechanism driving for δ Sct pulsations in A stars. In the last few years we have found with SuperWASP and Kepler observations that many Am stars do pulsate. More than half of all A stars pulsate at Kepler micromagnitude precision, yet there is a subset of A stars that truly do not pulsate at that level. Are these Am stars with the strongest signature of atomic diffusion? Is atomic diffusion the reason for the pulsational stability of these stars? The answers are not yet known.

  13. Pulsation-Driven Mass Loss in Luminous Blue Variables

    NASA Astrophysics Data System (ADS)

    Guzik, J. A.; Cox, A. N.; Despain, K. M.

    2005-09-01

    We use a nonlinear hydrodynamics code (Cox & Ostlie 1993) that includes a nonlocal time-dependent convection treatment to explore the pulsation of massive star models (Mo=50 and 80 M⊙) (see also Guzik et al. 1997, 1998, 1999). We find that for high-mass models near the Humphreys-Davidson limit, pulsations can grow to large amplitudes, exceeding 100 km/sec in radial velocity. The pulsations are similar to those of the LBV microvariations, with periods of 5 to 50 days, and light curve variations of about 0.1 mag. Ionization of Fe-group elements is occurring in the envelope at 200,000-500,000 K, producing a convective region that transports a varying amount of the emergent luminosity during the pulsation cycle. Because convection takes some time to turn on and off during a pulsation cycle, the outgoing radiation is periodically dammed up, and the Eddington limit is exceeded locally for that part of the pulsation cycle. The impulse imparted to the outer layers causes a large abrupt increase in their outward motion, which may be the beginning of an LBV `outburst'. Rotation (not included in these models) will also lower the effective gravitational binding of the outer layers. Since the envelopes of these stars contain only ˜10-4 M⊙, this mechanism perhaps could initiate mass loss of at most a few times x 10-4 M⊙/yr, in agreement with observed mass loss rates of LBV stars during an outburst. It is likely that the mass loss rate would be variable, modulated by the build-up of pulsation amplitude, requiring several pulsation cycles to accelerate, and would occur in shells or clumps. We suggest that this mechanism is responsible for the winds and outbursts of `normal' LBV stars such as S Dor or AG Car (Humphreys & Davidson 1994).

  14. 3D Convection-pulsation Simulations with the HERACLES Code

    NASA Astrophysics Data System (ADS)

    Felix, S.; Audit, E.; Dintrans, B.

    2015-10-01

    We present 3D simulations of the coupling between surface convection and pulsations due to the κ-mechanism in classical Cepheids of the red edge of Hertzsprung-Russell diagram's instability strip. We show that 3D convection is less powerful than 2D convection and does not quench the radiative pulsations, leading to an efficient 3D κ-mechanism. Thus, the 3D instability strip is closer to the observed one than the 1D or 2D were.

  15. An Update on the Quirks of Pulsating, Accreting White Dwarfs

    NASA Astrophysics Data System (ADS)

    Szkody, Paula; Mukadam, Anjum S.; Gänsicke, Boris T.; Hermes, J. J.; Toloza, Odette

    2015-06-01

    At the 18th European White Dwarf Workshop, we reported results for several dwarf novae containing pulsating white dwarfs that had undergone an outburst in 2006-2007. HST and optical data on the white dwarfs in GW Lib, EQ Lyn and V455 And all showed different behaviors in the years following their outbursts. We continued to follow these objects for the last 2 years, providing timescales of 6-7 years past outburst. All three reached their optical quiescent values within 4 years but pulsational stability has not returned. EQ Lyn showed its pre-outburst pulsation period after 3 years, but it continues to show photometric variability that alternates between pulsation and disk superhump periods while remaining at quiescence. V455 And has almost reached its pre-outburst pulsation period, while GW Lib still remains heated and with a different pulsation spectrum than at quiescence. These results indicate that asteroseismology provides a unique picture of the effects of outburst heating on the white dwarf.

  16. Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

    NASA Technical Reports Server (NTRS)

    Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

    1997-01-01

    Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

  17. a Search for Radial Pulsations in White Dwarfs

    NASA Astrophysics Data System (ADS)

    Kawaler, Steven

    1991-07-01

    Several classes of NONRADIALLY pulsating white dwarfs are known, with pulsation periods of several minutes. Theoretical work predicts that DB and DA white dwarfs that are slightly hotter than the known nonradial instability strips should be unstable to RADIAL pulsations with periods of about 0.1--1 second. However, ground-based observations have failed to reveal such periodicities. We propose to use HST's High Speed Photometer to search for the predicted radial pulsations in DB and DA white dwarfs. UV high-speed photometry offers the advantages of larger stellar fluxes (the effective temperatures of our three targets are 13,000--30,000 K) and significantly larger pulsation amplitudes (factors of 2 to 3) compared to ground-based photometry, along with freedom from atmospheric scintillation, giving HST a distinct gain over any ground-based facility. The presence (or absence) of the predicted rapid oscillations will provide significant new information for (or challenges to) the theory of white-dwarf pulsations, structure, and evolution.

  18. Influence of pulsation on start-up of UASB reactors.

    PubMed

    Franco, A; Gresia, G; Roca, E; Rozzi, A; Lema, J M

    2002-01-01

    The aim of this work is to study the influence of pulsation on the start-up of lab-scale UASB reactors. Pulsation was produced by an Elastic Membrane Pulsator (EMP). The application of this device in previous works improved the performance of continuous fixed-bed fermentors and reduced the formation of preferential pathways, the retention of gas metabolites within the bed and the resistance to mass transfer. These characteristics seem to be suitable for feeding UASB reactors. In this work, the influence of pulsation frequency was studied in two pulsed UASB reactors operated in parallel with a non-pulsed one. One of them (P1) operated at high frequencies (periods of 50 and 200 s between each pulsation) and the other (P2) at low frequencies (periods of 3600 and 900 s between each pulsation). An important improvement of the removal efficiency for pulsed reactors with respect to the non-pulsed one was obtained. The structure of the biomass was observed at the end of the process by scanning electron microscopy. In general, granulation of biomass was improved when operating in pulsing form.

  19. 45. INTERIOR VIEW SHOWING CONVEYOR BELT SYSTEM WHICH CONVEY THE ...

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

    45. INTERIOR VIEW SHOWING CONVEYOR BELT SYSTEM WHICH CONVEY THE HARDENED NAILS TO THE DRAWBACK TUBE FOR TEMPERING; MOTIONED STOPPED - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

  20. 19 CFR 123.24 - Sealing of conveyances or compartments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...; DEPARTMENT OF THE TREASURY CUSTOMS RELATIONS WITH CANADA AND MEXICO Shipments in Transit Through Canada or Mexico § 123.24 Sealing of conveyances or compartments. (a) Sealing required. Merchandise in...

  1. 27 CFR 19.588 - Construction of bulk conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... compartment) shall be so arranged that it can be completely drained. (3) Each tank car or tank truck shall... device, for carrying required marks or brands shall be provided on each bulk conveyance. (6)...

  2. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  3. These Pipes Are "Happening"

    ERIC Educational Resources Information Center

    Skophammer, Karen

    2010-01-01

    The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

  4. Unstable heat pipes

    SciTech Connect

    McGuinness, M.J.; Pruess, K.

    1987-10-01

    Heat pipes are an important feature of models of vapor-dominated geothermal reservoirs. Numerical experiments reveal that a vapor-dominated heat pipe is unstable if pressure is controlled at shallow levels. This instability is discussed in physical terms, and some implications for geothermal reservoirs are considered. 9 refs., 10 figs.

  5. PULSATION FREQUENCIES AND MODES OF GIANT EXOPLANETS

    SciTech Connect

    Le Bihan, Bastien; Burrows, Adam E-mail: burrows@astro.princeton.edu

    2013-02-10

    We calculate the eigenfrequencies and eigenfunctions of the acoustic oscillations of giant exoplanets and explore the dependence of the characteristic frequency {nu}{sub 0} and the eigenfrequencies on several parameters: the planet mass, the planet radius, the core mass, and the heavy element mass fraction in the envelope. We provide the eigenvalues for degree l up to 8 and radial order n up to 12. For the selected values of l and n, we find that the pulsation eigenfrequencies depend strongly on the planet mass and radius, especially at high frequency. We quantify this dependence through the calculation of the characteristic frequency {nu}{sub 0} which gives us an estimate of the scale of the eigenvalue spectrum at high frequency. For the mass range 0.5 M{sub J} {<=} M{sub P} {<=} 15 M{sub J} , and fixing the planet radius to the Jovian value, we find that {nu}{sub 0} {approx} 164.0 Multiplication-Sign (M{sub P} /M{sub J} ){sup 0.48}{mu}Hz, where M{sub P} is the planet mass and M{sub J} is Jupiter's mass. For the radius range from 0.9 to 2.0 R{sub J} , and fixing the planet's mass to the Jovian value, we find that {nu}{sub 0} {approx} 164.0 Multiplication-Sign (R{sub P} /R{sub J} ){sup -2.09}{mu}Hz, where R{sub P} is the planet radius and R{sub J} is Jupiter's radius. We explore the influence of the presence of a dense core on the pulsation frequencies and on the characteristic frequency of giant exoplanets. We find that the presence of heavy elements in the envelope affects the eigenvalue distribution in ways similar to the presence of a dense core. Additionally, we apply our formalism to Jupiter and Saturn and find results consistent with both the observational data of Gaulme et al. and previous theoretical work.

  6. Waste dislodging and conveyance testing summary and conclusions to date

    SciTech Connect

    Rinker, M.W.; Hatchell, B.K.; Mullen, O.D.

    1994-09-01

    This document summarizes recent work performed by the Waste Dislodging and Conveyance technology development program to provide assistance with the retrieval of wastes from the Hanford single-shell tanks (SSTs). This work is sponsored by the Underground Storage Tank-Integrated Demonstration (UST-ID) Office with the U.S. Department of Energy (DOE) Office of Technology Development. A baseline technology of high-pressure water-jet dislodging and pneumatic conveyance integrated as a scarifier is proposed as a means of retrieval. The tests and studies described were performed to demonstrate that at least one robust technology exists that could be effectively used with low water-addition arm-based systems. These results are preliminary and do not represent an optimized baseline. The Waste Dislodging and Conveyance work thus far has demonstrated that waterjet mobilization and air conveyance can mobilize and convey SST waste simulants at the target rates while operating within the space envelope and the dynamic loading constraints of deployment devices. The recommended technologies are well proven in industrial applications and are quite robust, yet lightweight and relatively benign to the retrieval environment. The baseline approach has versatility to continuously dislodge and convey a broad range of waste forms, from hard wastes to soft sludge wastes. The approach also has the major advantage of being noncontact with the waste surface under normal operation.

  7. Extendable pipe crawler

    DOEpatents

    Hapstack, Mark

    1991-01-01

    A pipe crawler having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by "inchworm"-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward.

  8. Extendable pipe crawler

    DOEpatents

    Hapstack, M.

    1991-05-28

    A pipe crawler is described having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by inchworm'-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward. 5 figures.

  9. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    PubMed

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

  10. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    PubMed

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes. PMID:26322761

  11. Some simple properties of stellar pulsation modes

    NASA Technical Reports Server (NTRS)

    Wolff, C. L.

    1979-01-01

    Except for the lowest harmonics, small-amplitude stellar pulsation modes possess many simple properties whose evaluation does not require numerical integration of the fourth-order equations of motion. All antinodes tend to have the same total kinetic energy except for those lying near physical or geometric boundaries. However, when kinetic energy per unit volume is considered, order-of-magnitude enhancements are seen in antinodes lying near the center of the star, and factor-of-2 enhancements occur near the polar axis. The nodes are distributed very regularly along the radius. They follow an exponential law in g-regions, and their separation is proportional to the sound travel time in p-regions. A simple graphical procedure is described for surveying the oscillation frequencies of a new stellar model. A precise condition is derived giving the division of energy between radial and angular motion. Another condition gives the fractional contribution to the velocity field of its two sources, the divergence and the curl. Certain simplifying results of weak coupling among the linear modes are briefly described.

  12. Sher 25: pulsating but apparently alone

    NASA Astrophysics Data System (ADS)

    Taylor, William D.; Evans, Christopher J.; Simón-Díaz, Sergio; Sana, Hugues; Langer, Norbert; Smith, Nathan; Smartt, Stephen J.

    2014-08-01

    The blue supergiant Sher 25 is surrounded by an asymmetric, hourglass-shaped circumstellar nebula, which shows similarities to the triple-ring structure seen around SN 1987A. From optical spectroscopy over six consecutive nights, we detect periodic radial velocity variations in the stellar spectrum of Sher 25 with a peak-to-peak amplitude of ˜12 km s-1 on a time-scale of about 6 d, confirming the tentative detection of similar variations by Hendry et al. From consideration of the amplitude and time-scale of the signal, coupled with observed line profile variations, we propose that the physical origin of these variations is related to pulsations in the stellar atmosphere, rejecting the previous hypothesis of a massive, short-period binary companion. The radial velocities of two other blue supergiants with similar bipolar nebulae, SBW1 and HD 168625, were also monitored over the course of six nights, but these did not display any significant radial velocity variations.

  13. Characterization of ULF Pulsations by THEMIS

    NASA Astrophysics Data System (ADS)

    Sarris, T. E.; Liu, W.; Kabin, K.; Li, X.; Elkington, S.; Ergun, R.; Rankin, R.; Angelopoulos, V.; Bonnel, J.; Glassmeier, K.; Auster, U.

    2008-12-01

    This paper reports the first use of THEMIS to determine the polarization properties of ULF waves in a non- dipolar magnetic topology: The instrumentation and the alignment at close distances (less than 1 RE) among some of the THEMIS probes (particularly in the first period of its mission) provides unique opportunities to characterize ULF pulsations in the magnetosphere and enables us to validate and parameterize existing models. In the case study presented, electric and magnetic field fluctuations are identified as field line resonances and their modes of oscillation are compared to model estimates. Out of the various modes predicted by the model, the second fundamental mode, or toroidal mode, appears to have most similarities to the measured polarizations. Furthermore, phase-difference calculations using the probes' small separations allow estimates of mode number and propagation characteristics. It is shown that these observations give an excellent source for the verification of model estimates of frequency and polarization of the various modes of field line resonances in the magnetosphere.

  14. Ionospheric signatures of cusp latitude Pc 3 pulsations

    SciTech Connect

    Engebretson, M.J.; Anderson, B.J. ); Cahill, L.J. Jr. ); Arnoldy, R.L. ); Rosenberg, T.J. ); Carpenter, D.L. ); Gail, W.B. ); Eather, R.H. )

    1990-03-01

    The authors have compared search coil magnetometer, riometer, photometer, and ELF-VLF receiver data obtained at South Pole Station and McMurdo, Antarctica, during selected days in March and April 1986. Narrow-band magnetic pulsations in the Pc 3 period range are observed simultaneously at both stations in the dayside sector during times of low interplanetary magnetic field (IMF) cone angle, but are considerably stronger at South Pole, which is located at a latitude near the nominal foot point of the daysie cusp/cleft region. Pulsations in auroral light a 427.8 nm wavelength are often observed with magnetic pulsations at South Pole, but such optical pulsations are not observed at McMurdo. When Pc 3 pulsations are present, they exhibit nearly identical frequencies, proportional to the magnitude of the IMF, in magnetometer, photometer, and ELF-VLF receiver signals at South Pole Station and in magnetometer signals at McMurdo. Singals from the 30-MHz riometer at South Pole are modulated in concert with the magnetic and optical variations during periods of broadband pulsation activity, but no riometer variations are noted during periods of narrow-band activity. Because riometers are sensitive to electrons of auroral energies (several keV and above), while the 427.8-nm photometer is sensitive to precipitation with much lower energies, they interpret these observatons as showing that precipitating magnetosheathlike electrons (with energies {le} 1 keV) at nominal dayside cleft latitudes are at times modulated with frequencies similar to those of upstream waves. They suggest that these particles may play an important role, via modification of ionospheric currents and conductivities, in the transmission of upstream wave signals into the magnetosphere and in the generation of dayside high-latitude Pc 3 pulsations.

  15. Constraining the neutrino magnetic dipole moment from white dwarf pulsations

    SciTech Connect

    Córsico, A.H.; Althaus, L.G.; García-Berro, E. E-mail: althaus@fcaglp.unlp.edu.ar E-mail: kepler@if.ufrgs.br

    2014-08-01

    Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μ{sub ν}) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pidot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pidot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μ{sub ν} ∼< 10{sup -11} μ{sub B}. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.

  16. Flexible ultrasonic pipe inspection apparatus

    DOEpatents

    Jenkins, C.F.; Howard, B.D.

    1994-01-01

    Pipe crawlers, pipe inspection {open_quotes}rabbits{close_quotes} and similar vehicles are widely used for inspecting the interior surfaces of piping systems, storage tanks and process vessels for damaged or flawed structural features. This paper describes the design of a flexible, modular ultrasonic pipe inspection apparatus.

  17. Experimenting with a "Pipe" Whistle

    ERIC Educational Resources Information Center

    Stafford, Olga

    2012-01-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

  18. An electrohydrodynamic heat pipe.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1972-01-01

    A heat pipe of new design, using an electrode structure to orient and guide the dielectric liquid phase flow, is proposed. Analysis indicates that the operation of the electrohydrodynamic heat pipe is in direct analogy to capillary devices, with the polarization force acting in place of capillarity. Advantages of these new heat pipes include greatly reduced liquid friction, electrohydrodynamically enhanced evaporation and condensation heat transfer, and a possible voltage-controlled on/off feature. Preliminary calculations indicate that relatively high performance devices are possible.

  19. Electrohydrodynamic heat pipes.

    NASA Technical Reports Server (NTRS)

    Jones, T. B.

    1973-01-01

    An electrohydrodynamic heat pipe of radical design is proposed which substitutes polarization electrohydrodynamic force effects for capillarity in collecting, guiding, and pumping a condensate liquid phase. The discussed device is restricted to the use of dielectric liquids as working fluids. Because of the relatively poor thermal transport properties of these liquids, capillary heat pipes using these liquids have not been high performance devices. The employment of the electrohydrodynamic concept should enhance this performance and help fill the performance gap that exists in the temperature range from 250 F to 750 F for 'conventional' capillary heat pipes.

  20. Gas pipe explorer robot

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian (Inventor)

    2004-01-01

    A gas pipe explorer formed of a plurality of connecting elements, and an articulation element between the connected elements. The connected elements include drive capabilities, and the articulation element allows the connected elements to traverse gas pipes of arbitrary shapes and sizes. A sensor may sends the characteristics of the gas pipe, and the communication element may send back those sends characteristics. The communication can be wired, over a tether connecting the device to a remote end. Alternatively, the connection can be wireless, driven by either a generator or a battery.

  1. AutoPIPE Extract Program

    SciTech Connect

    Cline, Barbara E.

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straight pipe, branch lines and ring geometries.

  2. AutoPIPE Extract Program

    1993-07-02

    The AutoPIPE Extract Program (APEX) provides an interface between CADAM (Computer Aided Design and Manufacturing) Release 21 drafting software and the AutoPIPE, Version 4.4, piping analysis program. APEX produces the AutoPIPE batch input file that corresponds to the piping shown in a CADAM model. The card image file contains header cards, material cards, and pipe cross section cards as well as tee, bend, valve, and flange cards. Node numbers are automatically generated. APEX processes straightmore » pipe, branch lines and ring geometries.« less

  3. Improved Thin, Flexible Heat Pipes

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Gernert, Nelson J.; Sarraf, David B.; Wollen, Peter J.; Surina, Frank C.; Fale, John E.

    2004-01-01

    Flexible heat pipes of an improved type are fabricated as layers of different materials laminated together into vacuum- tight sheets or tapes. In comparison with prior flexible heat pipes, these flexible heat pipes are less susceptible to leakage. Other advantages of these flexible heat pipes, relative to prior flexible heat pipes, include high reliability and greater ease and lower cost of fabrication. Because these heat pipes are very thin, they are highly flexible. When coated on outside surfaces with adhesives, these flexible heat pipes can be applied, like common adhesive tapes, to the surfaces of heat sinks and objects to be cooled, even if those surfaces are curved.

  4. Nonlinear convective pulsation models of type II Cepheids

    NASA Astrophysics Data System (ADS)

    Smolec, Radoslaw

    2015-08-01

    We present a grid of nonlinear convective pulsation models of type-II Cepheids: BL Her stars, W Vir stars and RV Tau stars. The models cover a wide range of masses, luminosities, effective temperatures and chemical compositions. The most interesting result is detection of deterministic chaos in the models. Different routes to chaos are detected (period doubling, intermittent route) as well as variety of phenomena intrinsic to chaotic dynamics (periodic islands within chaotic bands, crisis bifurcation, type-I and type-III intermittency). Some of the phenomena (period doubling in BL Her and in RV Tau stars, irregular pulsation of RV Tau stars) are well known in the pulsation of type-II Cepheids. Prospects of discovering the other are briefly discussed. Transition from BL Her type pulsation through W Vir type till RV Tau type is analysed. In the most luminous models a dynamical instability is detected, which indicates that pulsation driven mass loss is important process occurring in type-II Cepheids.

  5. Structure of Black Aurora Associated With Pulsating Aurora

    NASA Astrophysics Data System (ADS)

    Kenward, D. R.; Fritz, B.; Lessard, M.; Fernandes, P. A.; Blandin, M.

    2015-12-01

    Morphological behavior of black aurora as it relates to pulsating aurora is investigated by examining a collection of ground-based observations from January 2007 in support of the ROPA rocket campaign. Images were sampled from video recorded by a Xybion intensified camera (30 fps) at Poker Flat Research Range, AK. The primary observations of black aurora were observed during the substorm recovery phase and separate patches of pulsating aurora as well as pulsating aurora from diffuse aurora. In these observations the black aurora forms an apparent firm boundary between the auroral forms in a new behavior that is in contrast with previously reported observations. Also presented for the first time are black curls in conjunction with pulsating aurora. Curl structures that indicate shear plasma flows in the ionosphere may be used as a proxy for converging/diverging electric fields in and above the ionosphere. This new subset of black auroral behavior may provide visual evidence of black aurora as an ionospheric feedback mechanism as related to pulsating aurora.

  6. THE DISCOVERY OF PULSATING HOT SUBDWARFS IN NGC 2808

    SciTech Connect

    Brown, Thomas M.; Landsman, Wayne B.; Randall, Suzanna K.; Sweigart, Allen V.; Lanz, Thierry E-mail: Wayne.Landsman@nasa.gov E-mail: allen.sweigart@gmail.com

    2013-11-10

    We present the results of a Hubble Space Telescope program to search for pulsating hot subdwarfs in the core of NGC 2808. These observations were motivated by the recent discovery of such stars in the outskirts of ω Cen. Both NGC 2808 and ω Cen are massive globular clusters exhibiting complex stellar populations and large numbers of extreme horizontal branch stars. Our far-UV photometric monitoring of over 100 hot evolved stars has revealed six pulsating subdwarfs with periods ranging from 85 to 149 s and UV amplitudes of 2.0%-6.8%. In the UV color-magnitude diagram of NGC 2808, all six of these stars lie immediately below the canonical horizontal branch, a region populated by the subluminous 'blue-hook' stars. For three of these six pulsators, we also have low-resolution far-UV spectroscopy that is sufficient to broadly constrain their atmospheric abundances and effective temperatures. Curiously, and in contrast to the ω Cen pulsators, the NGC 2808 pulsators do not exhibit the spectroscopic or photometric uniformity one might expect from a well-defined instability strip, although they all fall within a narrow band (0.2 mag) of far-UV luminosity.

  7. The Discovery of Pulsating Hot Subdwarfs in NGC 2808

    NASA Technical Reports Server (NTRS)

    Brown, Thomas M.; Landsman, Wayne B.; Randall, Suzanna K.; Sweigert, Allen V.; Lanz, Thierry

    2013-01-01

    We present the results of a Hubble Space Telescope program to search for pulsating hot subdwarfs in the core of NGC 2808. These observations were motivated by the recent discovery of such stars in the outskirts of Omega Cen. Both NGC 2808 and ? Cen are massive globular clusters exhibiting complex stellar populations and large numbers of extreme horizontal branch stars. Our far-UV photometric monitoring of over 100 hot evolved stars has revealed six pulsating subdwarfs with periods ranging from 85 to 149 s and UV amplitudes of 2.0%-6.8%. In the UV color-magnitude diagram of NGC 2808, all six of these stars lie immediately below the canonical horizontal branch, a region populated by the subluminous "blue-hook" stars. For three of these six pulsators, we also have low-resolution far-UV spectroscopy that is sufficient to broadly constrain their atmospheric abundances and effective temperatures. Curiously, and in contrast to the ? Cen pulsators, the NGC 2808 pulsators do not exhibit the spectroscopic or photometric uniformity one might expect from a well-defined instability strip, although they all fall within a narrow band (0.2 mag) of far-UV luminosity.

  8. The Effects of Pulsating Flow on Eruption Column Dynamics

    NASA Astrophysics Data System (ADS)

    Black, T.; Dufek, J.; Benage, M. C.

    2015-12-01

    Pulsating flow, at frequencies ranging from 10-2 to 101 Hz, has been recorded in explosive eruptions through video, thermal imagery, and infrasonic and seismic data. Such pulsating flow can be generated from instabilities in bubbly magma, and from granular instabilities in post-fragmentation conduit flow. Variable fluxes of gas and particles at the vent can alter entrainment conditions, and consequently affect eruption column stability. However, volcanic eruption models typically assume steady flow from the vent, and regime diagrams of eruption column stability are based on such steady flow assumptions. Using Eulerian-Eulerian multiphase numerical simulations of eruption columns with both steady and pulsating sources, we compared the relative behavior of steady and pulsed columns across a range of pulse frequencies and mass fluxes at the vent (mass flux is time-averaged for pulsating cases). Preliminary results suggest that pulsating flow increases air entrainment into the column relative to steady flow for otherwise constant eruption conditions, and that entrainment increases with decreasing pulse frequency. Increased entrainment at low frequency implies that low-frequency pulsed columns are more buoyant and potentially more stable than their steady counterparts, for a given mass flux. This effect disrupts the steady flow-based understanding of eruption column stability regimes and may be a factor to consider for future assessment of volcanic hazards and interpreting mass flux conditions from deposits.

  9. Non-adiabatic pulsations in %delta; Scuti stars

    NASA Astrophysics Data System (ADS)

    Moya, A.; Garrido, R.; Dupret, M. A.

    2004-01-01

    For δ Scuti stars, phase differences and amplitude ratios between the relative effective temperature variation and the relative radial displacement can be derived from multicolor photometric observations. The same quantities can be also calculated from theoretical non-adiabatic pulsation models. We present here these theoretical results, which indicate that non-adiabatic quantities depend on the mixing length parameter α used to treat the convection in the standard Mixing Length Theory (MLT). This dependence can be used to test and to constrain, through multicolor observations, the way MLT describes convection in the outermost layers of the star. We will use the equilibrium models provided by the CESAM evolutionary code. The pulsational observables are calculated by using a non-adiabatic pulsation code developed by R. Garridon and A. Moya. In the evolutionary and pulsation codes, a complete reconstruction of the non-grey atmosphere (Kurucz models) is included. The interaction between pulsation and atmosphere, as described by Dupret et al. (2002), is also included in the code.

  10. Lattice melting and rotation in perpetually pulsating equilibria

    SciTech Connect

    Pichon, C.; Lynden-Bell, D.; Pichon, J.; Lynden-Bell, R.

    2007-01-15

    Systems whose potential energies consists of pieces that scale as r{sup -2} together with pieces that scale as r{sup 2}, show no violent relaxation to Virial equilibrium but may pulsate at considerable amplitude forever. Despite this pulsation these systems form lattices when the nonpulsational ''energy'' is low, and these disintegrate as that energy is increased. The ''specific heats'' show the expected halving as the ''solid'' is gradually replaced by the ''fluid'' of independent particles. The forms of the lattices are described here for N{<=}18 and they become hexagonal close packed for large N. In the larger N limit, a shell structure is formed. Their large N behavior is analogous to a {gamma}=5/3 polytropic fluid with a quasigravity such that every element of fluid attracts every other in proportion to their separation. For such a fluid, we study the ''rotating pulsating equilibria'' and their relaxation back to uniform but pulsating rotation. We also compare the rotating pulsating fluid to its discrete counterpart, and study the rate at which the rotating crystal redistributes angular momentum and mixes as a function of extra heat content.

  11. Proposed method for measurement of flow rate in turbulent periodic pipe flow

    NASA Astrophysics Data System (ADS)

    Werzner, E.; Ray, S.; Trimis, D.

    2011-12-01

    The present investigation deals with a previously proposed flow metering technique for laminar, fully-developed, time-periodic pipe flow. Employing knowledge of the pulsation frequency-dependent relationship between the mass flow rate and the pressure gradient, the method allows reconstruction of the instantaneous mass flow rate on the basis of a recorded pressure gradient time series. In order to explore if the procedure can be extended for turbulent flows, numerical simulations for turbulent, fully-developed, sinusoidally pulsating pipe flow with low pulse amplitude have been carried out using a ν2-f turbulence model. The study covers pulsation frequencies, ranging from the quasi-steady up to the inertia-dominated frequency regime, and three cycle-averaged Reynolds numbers of 4360, 9750 and 15400. After providing the theoretical background of the flow rate reconstruction principle, the numerical model and an experimental facility for the verification of simulations are explained. The obtained results, presented in time and frequency domain, show good agreement with each other and indicate a frequency dependence, similar to that used for the signal reconstruction for laminar flows. A modified dimensionless frequency definition has been introduced, which allows a generalised representation of the results considering the influence of Reynolds number.

  12. Epsilon Aur monitoring during predicted pulsation phase

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.; Templeton, Matthew R.

    2014-09-01

    Dr. Robert Stencel (University of Denver Astronomy Program) has requested that AAVSO observers monitor epsilon Aurigae from now through the end of the observing season. "Studies of the long-term, out-of-eclipse photometry of this enigmatic binary suggest that intervals of coherent pulsation occur at roughly 1/3 of the 27.1-year orbital period. Kloppenborg, et al. noted that stable variation patterns develop at 3,200-day intervals' implying that 'the next span of dates when such events might happen are circa JD ~2457000 (2014 December)'. "These out-of-eclipse light variations often have amplitudes of ~0.1 magnitude in U, and ~0.05 in V, with characteristic timescales of 60-100 days. The AAVSO light curve data to the present may indicate that this coherent phenomenon has begun, but we encourage renewed efforts by observers...to help deduce whether these events are internal to the F star, or externally-driven by tidal interaction with the companion star." Nightly observations or one observation every few days (CCD/PEP/DSLR, VUBR (amplitude too small for visual)) are requested. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. Epsilon Aur was the subject of major international campaigns and the AAVSO's Citizen Sky project as it went through its 27.1-year eclipse in 2009-2011. Over 700 observers worldwide submitted over 20,000 multicolor observations to the AAVSO International Database for this project. Much information on eps Aur is available from the AAVSO, including material on the Citizen Sky website (http://www.aavso.org/epsilon-aurigae and http://www.citizensky.org/content/star-our-project). The Journal of the AAVSO, Volume 40, No. 2 (2012) was devoted to discussion of and research results from this event. See full Alert Notice for more details and observations.

  13. Heat pipe manufacturing study

    NASA Technical Reports Server (NTRS)

    Edelstein, F.

    1974-01-01

    Heat pipe manufacturing methods are examined with the goal of establishing cost effective procedures that will ultimately result in cheaper more reliable heat pipes. Those methods which are commonly used by all heat pipe manufacturers have been considered, including: (1) envelope and wick cleaning, (2) end closure and welding, (3) mechanical verification, (4) evacuation and charging, (5) working fluid purity, and (6) charge tube pinch off. The study is limited to moderate temperature aluminum and stainless steel heat pipes with ammonia, Freon-21 and methanol working fluids. Review and evaluation of available manufacturers techniques and procedures together with the results of specific manufacturing oriented tests have yielded a set of recommended cost-effective specifications which can be used by all manufacturers.

  14. The pipes of pan.

    PubMed

    Chalif, David J

    2004-12-01

    The pipes of pan is the crowning achievement of Pablo Picasso's neoclassical period of the 1920s. This monumental canvas depicts a mythological Mediterranean scene in which two sculpted classical giants stare out, seemingly across the centuries, toward a distant and lost Arcadia. Picasso was influenced by Greco-Roman art during his travels in Italy, and his neoclassical works typically portray massive, immobile, and pensive figures. Pan and his pipes are taken directly from Greek mythological lore by Picasso and placed directly into 20th century art. He frequently turned to various mythological figures throughout his metamorphosing periods. The Pipes of Pan was also influenced by the painter's infatuation with the beautiful American expatriate Sara Murphy, and the finished masterpiece represents a revision of a previously conceived neoclassical work. The Pipes of Pan now hangs in the Musee Picasso in Paris.

  15. Ceramic heat pipe development

    NASA Astrophysics Data System (ADS)

    Merrigan, M.

    1980-09-01

    Ceramic materials used in conventional brickwork heat exchanger configurations increase allowable temperatures; however, joint leakage problems limit use of these designs. Ceramic tube heat exchanger designs reduce these problems but still require sliding joints and compliant tube end seals. Ceramic heat pipe based recuperator designs eliminate the sealing problems that limited the high temperature heat recovery installations. Heat pipe recuperators offer high corrosion and abrasion resistance, high temperature capability, reduced leakage, element redundancy, and simplified replacement and cleaning. The development of ceramic heat pipe recuperator elements involves the selection and test of materials and fabrication techniques having production potential, evaluation of technology in subscale tests, design and test of components for full scale recuperator applications, and demonstration of heat pipes in subscale and full scale recuperator installation.

  16. Miniature pipe crawler tractor

    SciTech Connect

    McKay, M.D.; Anderson, M.O.; Ferrante, T.A.; Willis, W.D.

    2000-03-14

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  17. Heat Pipe Systems

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The heat pipe was developed to alternately cool and heat without using energy or any moving parts. It enables non-rotating spacecraft to maintain a constant temperature when the surface exposed to the Sun is excessively hot and the non Sun-facing side is very cold. Several organizations, such as Tropic-Kool Engineering Corporation, joined NASA in a subsequent program to refine and commercialize the technology. Heat pipes have been installed in fast food restaurants in areas where humid conditions cause materials to deteriorate quickly. Moisture removal was increased by 30 percent in a Clearwater, FL Burger King after heat pipes were installed. Relative humidity and power consumption were also reduced significantly. Similar results were recorded by Taco Bell, which now specifies heat pipe systems in new restaurants in the Southeast.

  18. Miniature pipe crawler tractor

    DOEpatents

    McKay, Mark D.; Anderson, Matthew O.; Ferrante, Todd A.; Willis, W. David

    2000-01-01

    A pipe crawler tractor may comprise a half tractor assembly having a first base drive wheel, a second base drive wheel, and a top drive wheel. The drive wheels are mounted in spaced-apart relation so that the top drive wheel is positioned between the first and second base drive wheels. The mounting arrangement is also such that the first and second base drive wheels contact the inside surface of the pipe at respective first and second positions and so that the top drive wheel contacts the inside surface of the pipe at a third position, the third position being substantially diametrically opposed to the first and second positions. A control system connected to the half tractor assembly controls the rotation of the first base wheel, the second base wheel, and the top drive wheel to move the half tractor assembly within the pipe.

  19. Freezable heat pipe

    DOEpatents

    Ernst, Donald M.; Sanzi, James L.

    1981-02-03

    A heat pipe whose fluid can be repeatedly frozen and thawed without damage to the casing. An additional part is added to a conventional heat pipe. This addition is a simple porous structure, such as a cylinder, self-supporting and free standing, which is dimensioned with its diameter not spanning the inside transverse dimension of the casing, and with its length surpassing the depth of maximum liquid.

  20. Silicon Heat Pipe Array

    NASA Technical Reports Server (NTRS)

    Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

    2013-01-01

    Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better

  1. ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE ...

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

    ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE MINES ABOVE AT THE RIDGELINE AND TO THE RIGHT WAS CONVEYED TO THIS AREA AND DUMPED INTO THE SHAFT AT CENTER. THIS SHAFT OPENS INTO THE ADIT AT BOTTOM CENTER. THERE IS ANOTHER SHAFT OPENING INTO THE ADIT JUST ABOVE THE ADIT BEHIND THE STONE WALL. THE ORE WAS LOADED INTO TRAM CARS INSIDE THE ADIT AND CONVEYED ON TRACKS TO THE TRESTLE LEADING TO THE PRIMARY ORE BIN AT THE TRAM TERMINAL. TRACKS CAN BE SEEN LEADING FROM THE ADIT AND TO THE LEFT. THE ORE WAS THEN DUMPED INTO A CHUTE AT THE END OF THE TRESTLE CARRYING IT INTO THE ORE BIN AT THE TRAM TERMINAL(SEE CHUTE ON CA-291-30). - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  2. Heat pipe dynamic behavior

    NASA Technical Reports Server (NTRS)

    Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

    1988-01-01

    The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

  3. Water Conveyance Infrastructure Research Needs: An EPA/ORD Perspective

    EPA Science Inventory

    This is a Powerpoint presentation that identifies pipe/pipeline related research needs that have been identified in several Agency Research programs including Safe & Sustainable Water Research, Aging Water Infrastucture Research, & Distribution Systems Research and Information Co...

  4. Exhaust pressure pulsation observation from turbocharger instantaneous speed measurement

    NASA Astrophysics Data System (ADS)

    Macián, V.; Luján, J. M.; Bermúdez, V.; Guardiola, C.

    2004-06-01

    In internal combustion engines, instantaneous exhaust pressure measurements are difficult to perform in a production environment. The high temperature of the exhaust manifold and its pulsating character make its application to exhaust gas recirculation control algorithms impossible. In this paper an alternative method for estimating the exhaust pressure pulsation is presented. A numerical model is built which enables the exhaust pressure pulses to be predicted from instantaneous turbocharger speed measurements. Although the model is data based, a theoretical description of the process is also provided. This combined approach makes it possible to export the model for different engine operating points. Also, compressor contribution in the turbocharger speed pulsation is discussed extensively. The compressor contribution is initially neglected, and effects of this simplified approach are analysed.

  5. Ultra-low-frequency magnetic pulsations in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Anderson, Brian J.

    1990-01-01

    Spacecraft observations have shown that geomagnetic pulsations originating in magnetospheric processes, in spite of their small amplitude on the ground, have amplitudes in space relative to the local magnetic field of 5-10 percent and occasionally up to about 50 percent. It is noted that by studying geomagnetic pulsations, a detailed comparison can be made between plasma physics theory and observations that are not possible in laboratory experiments. Also geomagnetic pulsations play a role in magnetospheric dynamics and energy transport, and their study forms an integral part of enhancing the knowledge of the magnetosphere. The importance of spacecraft observations are discussed and attention is given to such topics as waves in the magnetosphere, field-line resonances, the quantitative analysis of a dipole field, plasma instabilities, and energy flow.

  6. Ground magnetic field fluctuations associated with pulsating aurora

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Samara, M.

    2015-10-01

    A case study of an intense pulsating auroral event is presented where the large-scale (100-200 km) optical intensity variations are anticorrelated with fluctuations in the ground magnetometer data at a frequency of 0.1 Hz. The auroral event occurred over Poker Flat, Alaska, on 1 March 2012 and was imaged optically with several different fields of view and filters. The fluctuations in the magnetometer data were most prominent in the D component and had magnitudes of 1 to 5 nT. The auroral intensity variations had amplitudes of 200 to 400 R, comprising 25% to 50% of the total auroral luminosity at 427.8 nm. The direction of the magnetometer deflections is consistent with a south-to-north ionospheric current present when each pulsation is on, thus providing closure for the field-aligned currents associated with each of the pulsating patches.

  7. Outbursts in Two New Cool Pulsating DA White Dwarfs

    NASA Astrophysics Data System (ADS)

    Bell, Keaton J.; Hermes, J. J.; Montgomery, M. H.; Gentile Fusillo, N. P.; Raddi, R.; Gänsicke, B. T.; Winget, D. E.; Dennihy, E.; Gianninas, A.; Tremblay, P.-E.; Chote, P.; Winget, K. I.

    2016-10-01

    The unprecedented extent of coverage provided by Kepler observations recently revealed outbursts in two hydrogen-atmosphere pulsating white dwarfs (DAVs) that cause hours-long increases in the overall mean flux of up to 14%. We have identified two new outbursting pulsating white dwarfs in K2, bringing the total number of known outbursting white dwarfs to four. EPIC 211629697, with {T}{eff} = 10,780 ± 140 K and {log} g = 7.94 ± 0.08, shows outbursts recurring on average every 5.0 days, increasing the overall flux by up to 15%. EPIC 229227292, with {T}{eff} = 11,190 ± 170 K and {log} g = 8.02 ± 0.05, has outbursts that recur roughly every 2.4 days with amplitudes up to 9%. We establish that only the coolest pulsating white dwarfs within a small temperature range near the cool, red edge of the DAV instability strip exhibit these outbursts.

  8. On the Stenbaek-Nielsen and Hallinan pulsating auroras

    SciTech Connect

    D'Angelo, N. )

    1991-02-01

    Stenbaek-Nielsen and Hallinan (1979) argued that if the pulsating auroras are caused by precipitating electrons, the data suggest that noncollisional interactions, localized in the lower E region (90-107 km), where most of the pulsations are observed, may play a dominant role in thermalizing the particles. They also stated that one type of process that comes to mind is a wave-particle interaction in the ionosphere. If, through one or more instabilities, waves grow at the expense of beam energy and, in turn, energize ambient electrons, the energized ambient electrons could ionize the background gas and, in process, produce luminosity. The exceptionally thin pulsating auroral patches observed by Stenbaek-Nielsen and Hallinan (1979) may be caused by an ionization instability occurring at the end of the range of precipitating electrons. A comparison is made to laboratory results reported by Johnson et al. (1990).

  9. On the Role of Resonances in Nonradial Pulsators

    NASA Technical Reports Server (NTRS)

    Buchler, J. R.; Goupil, M. J.; Hansen, C. J.

    1997-01-01

    Resonances or near resonances are ubiquitous among the excited nonradial pulsation modes of variable stars and they must play an important role in determining their pulsational behavior. Here in a first step at nonlinear asteroseismology, we explore some of the consequences of resonances by means of the amplitude equation formalism. We show how parity and angular momentum constraints can be used to eliminate many of the possible nonlinear resonant couplings between modes (and multiplets of modes), and how the amplitude equations can thus be simplified. Even when we may not be able, nor wish, to make an ab initio computation of the values of the coupling coefficients, it is still possible to obtain constraints on the nature of the excited modes if a resonance between observed frequencies can be identified. Resonances can cause nonlinear frequency locking of modes. This means that the observed frequencies appear in exact resonance even though the linear frequencies are only approximately in resonance. The nonlinear frequency lock, when it occurs, it does so over a range of departures from linear resonance, and it is accompanied by constant pulsation amplitudes. The locked, nonlinear frequencies can differ noticeably from their nonresonant counterparts which are usually used in seismology. This is particularly true for multiplets of modes split by rotation. Beyond the regime of the frequency lock, amplitude and frequency modulations can appear in the pulsations. Far from the resonance condition one recovers the regime of steady pulsations with nonresonant frequencies for which the seismological studies, as they are presently carried out, are justified (provided furthermore, of course, that nonlinear frequency shifts are negligible). Success in identifying a resonance in an observed power spectrum depends on the quality of the data. While keeping this limitation in mind, ew discuss the possible existence of peculiar resonances the pulsations specific variable white

  10. Generation of traveling atmospheric disturbances during pulsating geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Gardner, Larry; Schunk, Robert

    Traveling Atmospheric Disturbances (TADs) are effective in transporting momentum and en-ergy deposited at high latitudes to the mid and low latitude regions of the thermosphere. They also act to transport momentum and energy from the lower thermosphere into the upper ther-mosphere. Previously, model studies have been conducted to determine the characteristics of isolated, single-pulse TADs, but the generation of multiple TADs excited during pulsating storms have not been considered before. Here, a high-resolution global thermosphere-ionosphere model was used to study the basic characteristic of multiple TADs excited during pulsating storms, including idealized weak and strong pulsating storms, and an approximation of the May 4, 1998 pulsating storm. For all three pulsating storm simulations, multiple TADs were excited that propagated away form the auroral oval both toward the poles and toward the equator at all longitudes, with the maximum amplitudes between midnight and dawn. The TAD amplitudes were a maximum near the poles, diminished towards the equator and were larger on the nightside than on the dayside. The TADs propagated at a slight upward angle to the horizontal, with the result that the lower boundary of the TADs increased with decreas-ing latitude. The TADs crossed the equator and propagated to mid-latitudes in the opposite hemisphere, where wave interference occurred for the strong pulsating storm cases. The TAD wavelengths vary from 2500-3000 km and the phase speeds from 800-1000 m/s. The maximum TAD perturbations are 20% for the mass density 14% for the neutral temperature and 100 m/s for the winds.

  11. Generation of traveling atmospheric disturbances during pulsating geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Gardner, L. C.; Schunk, R. W.

    2010-08-01

    Traveling atmospheric disturbances (TADs) are effective in transporting momentum and energy deposited at high latitudes to the midlatitude and low-latitude regions of the thermosphere. They also act to transport momentum and energy from the lower thermosphere into the upper thermosphere. Previously, model studies have been conducted to determine the characteristics of isolated, single-pulse TADs, but the generation of multiple TADs excited during pulsating storms have not been considered before. Here a high-resolution global thermosphere-ionosphere model was used to study the basic characteristics of multiple TADs excited during pulsating storms, including idealized weak and strong pulsating storms, and an approximation of the 4 May 1998 pulsating storm. For all three pulsating storm simulations, multiple TADs that propagated away from the auroral oval toward both the poles and the equator at all longitudes, with the maximum amplitudes between midnight and dawn, were excited. The TAD amplitudes were at maximum near the poles and diminished toward the equator and were larger on the nightside than on the dayside. The TADs propagated at a slightly upward angle to the horizontal, with the result that the lower boundary of the TADs increased with decreasing latitude. The TADs crossed the equator and propagated to midlatitudes in the opposite hemisphere, where wave interference occurred for the strong pulsating storm cases. The TAD wavelengths vary from 2500 to 3000 km and the phase speeds vary from 800 to 1000 m/s. The maximum TAD perturbations are 20% for the mass density, 14% for the neutral temperature, and 100 m/s for the winds.

  12. MOST photometry of the enigmatic PMS pulsator HD 142666

    NASA Astrophysics Data System (ADS)

    Zwintz, K.; Kallinger, T.; Guenther, D. B.; Gruberbauer, M.; Huber, D.; Rowe, J.; Kuschnig, R.; Weiss, W. W.; Matthews, J. M.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov, D.; Walker, G. A. H.; Casey, M. P.

    2009-02-01

    Context: Modeling of pre-main sequence (PMS) stars through asteroseismology of PMS p-mode pulsators has only recently become possible, and spacebased photometry is one of the important sources of data for these efforts. We present precise photometry of the pulsating Herbig Ae star HD 142666 obtained in two consecutive years with the MOST (Microvariability & Oscilations of STars) satellite. Aims: Previously, only a single pulsation period was known for HD 142666. The MOST photometry reveals that HD 142666 is multi-periodic. However, the unique identification of pulsation frequencies is complicated by the presence of irregular variability caused by the star's circumstellar dust disk. The two light curves obtained with MOST in 2006 and 2007 provided data of unprecedented quality to study the pulsations in HD 142666 and also to monitor the circumstellar variability. Methods: Frequency analysis was performed using the routine sigspec and the results from the 2006 and 2007 campaigns were then compared to each other with the software cinderella to identify frequencies common to both light curves. The correlated frequencies were then submitted to an asteroseismic analysis. Results: We attribute 12 frequencies to pulsation. Model fits to the three frequencies with the highest amplitudes lie well outside the uncertainty box for the star's position in the HR diagram based on published values. Some of the frequencies appear to be rotationally split modes. Conclusions: The models suggest that either (1) the published estimate of the luminosity of HD 142666, based on a relation between circumstellar disk radius and stellar luminosity, is too high and/or (2) additional physics such as mass accretion may be needed in our models to accurately fit both the observed frequencies and HD 142666's position in the HR diagram. Based on data from the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute for Aerospace Studies

  13. 27 CFR 19.391 - Removals by bulk conveyances or pipelines.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... conveyances or pipelines. 19.391 Section 19.391 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX....391 Removals by bulk conveyances or pipelines. When the spirits in the processing accounts are to be removed in bulk conveyances or by pipeline, the proprietor shall record the filling of the conveyance...

  14. Spectral peculiarities of turbulent pulsations of submerged water jets

    NASA Astrophysics Data System (ADS)

    Znamenskaya, I. A.; Koroteeva, E. Yu.; Novinskaya, A. M.; Sysoev, N. N.

    2016-07-01

    The spectra of turbulent jet temperature pulsations at 1-40 Hz frequencies have been experimentally studied based on high-speed thermography of the water boundary layer: the region where an impact jet interacts with a surface transparent to IR radiation, as well as the near-wall region where two submerged jets interact in a disc-shaped tee-joint. It has been indicated that the slopes of the spectra of impact submerged jet turbulent pulsations are close to-5/3 and a double inertial interval exists in a quasi-2D turbulent flow that is formed when two jets mix.

  15. Latitude distribution of nonradial pulsations in rapidly rotating B stars

    NASA Astrophysics Data System (ADS)

    Jankov, S.; Mathias, P.; Domiciano de Souza, A., Jr.; Uytterhoeven, K.; Aerts, C.

    2004-05-01

    We present a method for the analysis of latitude distribution associated with temperature and/or velocity perturbations of the stellar surface due to non-radial pulsation (NRP) modes in rapidly rotating B stars. The technique is applied together with Fourier Doppler Imaging (FDI) to high resolution and high signal-to-noise ratio spectroscopic observations of ɛ Per. The main advantage of this approach is that it decomposed complex multi-periodic line profile variations into single components, allowing the detailed analysis of each mode seperately. We study the 10.6-d-1 frequency that is particularly important for modal analysis of non-radial pulsations in the star.

  16. Search for optical pulsations in PSR J0337+1715

    DOE PAGES

    Strader, M. J.; Archibald, A. M.; Meeker, S. R.; Szypryt, P.; Walter, A. B.; van Eyken, J. C.; Ulbricht, G.; Stoughton, C.; Bumble, B.; Kaplan, D. L.; et al

    2016-03-20

    In this study, we report on a search for optical pulsations from PSR J0337+1715 at its observed radio pulse period. PSR J0337+1715 is a millisecond pulsar (2.7 ms spin period) in a triple hierarchical system with two white dwarfs, and has a known optical counterpart with g-band magnitude 18. The observations were done with the Array Camera for Optical to Near-IR Spectrophotometry (ARCONS) at the 200" Hale telescope at Palomar Observatory. No significant pulsations were found in the range 4000-11000 angstroms, and we can limit pulsed emission in g-band to be fainter than 25 mag.

  17. Cycles of self-pulsations in a photonic integrated circuit.

    PubMed

    Karsaklian Dal Bosco, Andreas; Kanno, Kazutaka; Uchida, Atsushi; Sciamanna, Marc; Harayama, Takahisa; Yoshimura, Kazuyuki

    2015-12-01

    We report experimentally on the bifurcation cascade leading to the appearance of self-pulsation in a photonic integrated circuit in which a laser diode is subjected to delayed optical feedback. We study the evolution of the self-pulsing frequency with the increase of both the feedback strength and the injection current. Experimental observations show good qualitative accordance with numerical results carried out with the Lang-Kobayashi rate equation model. We explain the mechanism underlying the self-pulsations by a phenomenon of beating between successive pairs of external cavity modes and antimodes.

  18. Resonant self-pulsations in coupled nonlinear microcavities

    SciTech Connect

    Grigoriev, Victor; Biancalana, Fabio

    2011-04-15

    A different point of view on the phenomenon of self-pulsations is presented, which shows that they are a balanced state formed by two counteracting processes: beating of modes and bistable switching. A structure based on two coupled nonlinear microcavities provides a generic example of a system with enhanced ability to support this phenomenon. The specific design of such a structure in the form of multilayered media is proposed, and the coupled-mode theory is applied to describe its dynamical properties. It is emphasized that the frequency of self-pulsations is related to the frequency splitting between resonant modes and can be adjusted over a broad range.

  19. Mode identification from spectroscopy of gravity-mode pulsators

    NASA Astrophysics Data System (ADS)

    Pollard, K. R.; Brunsden, E.; Cottrell, P. L.; Davie, M.; Greenwood, A.; Wright, D. J.; De Cat, P.

    2014-02-01

    The gravity modes present in γ Doradus stars probe the deep stellar interiors and are thus of particular interest in asteroseismology. For the MUSICIAN programme at the University of Canterbury, we obtain extensive high-resolution echelle spectra of γ Dor stars from the Mt John University Observatory in New Zealand. We analyze these to obtain the pulsational frequencies and identify these with the multiple pulsational modes excited in the star. A summary of recent results from our spectroscopic mode-identification programme is given.

  20. Heat Pipe Integrated Microsystems

    SciTech Connect

    Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.

    1999-03-30

    The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to

  1. 14 CFR 49.21 - Return of original conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Return of original conveyance. 49.21 Section 49.21 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... the applicant stamped with the date and time of recording. The copy must be imprinted on...

  2. 7 CFR 766.354 - Voluntary conveyance of chattel.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... income and potential earning ability; (4) A bill of sale including each item and titles to all vehicles... subpart B of 7 CFR part 1956 before or in conjunction with the voluntary conveyance offer if the value of... will credit the borrower's account in the amount of the market value of the chattel....

  3. 21 CFR 1250.51 - Railroad conveyances; discharge of wastes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Section 1250.51 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...; discharge of wastes. (a) New railroad conveyances. Human wastes, garbage, waste water, or other polluting... Commissioner of Food and Drugs. In lieu of retention pending discharge at approved servicing areas,...

  4. 21 CFR 1250.51 - Railroad conveyances; discharge of wastes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Section 1250.51 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...; discharge of wastes. (a) New railroad conveyances. Human wastes, garbage, waste water, or other polluting... Commissioner of Food and Drugs. In lieu of retention pending discharge at approved servicing areas,...

  5. 21 CFR 1250.51 - Railroad conveyances; discharge of wastes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Railroad conveyances; discharge of wastes. 1250.51 Section 1250.51 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION...

  6. 21 CFR 1250.51 - Railroad conveyances; discharge of wastes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Railroad conveyances; discharge of wastes. 1250.51 Section 1250.51 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION...

  7. 7 CFR 330.401 - Garbage generated onboard a conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and vegetables... countries designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and...; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Garbage § 330.401 Garbage generated onboard a conveyance....

  8. 7 CFR 330.209 - Permits for means of conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Permits for means of conveyance. 330.209 Section 330.209 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS;...

  9. 7 CFR 330.401 - Garbage generated onboard a conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and vegetables... countries designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and...; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Garbage § 330.401 Garbage generated onboard a conveyance....

  10. 7 CFR 330.209 - Permits for means of conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Permits for means of conveyance. 330.209 Section 330.209 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS;...

  11. 7 CFR 330.401 - Garbage generated onboard a conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and vegetables... countries designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and...; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Garbage § 330.401 Garbage generated onboard a conveyance....

  12. 7 CFR 330.209 - Permits for means of conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Permits for means of conveyance. 330.209 Section 330.209 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS;...

  13. 7 CFR 330.401 - Garbage generated onboard a conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and vegetables... countries designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and...; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Garbage § 330.401 Garbage generated onboard a conveyance....

  14. 7 CFR 330.209 - Permits for means of conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Permits for means of conveyance. 330.209 Section 330.209 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS;...

  15. 7 CFR 330.209 - Permits for means of conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Permits for means of conveyance. 330.209 Section 330.209 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS;...

  16. 7 CFR 330.401 - Garbage generated onboard a conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and vegetables... countries designated in 9 CFR 94.1 as those in which foot-and-mouth disease exists; all fresh fruits and...; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Garbage § 330.401 Garbage generated onboard a conveyance....

  17. Schoolchildren's Use of Poetry and Paintings in Conveying Environmental Messages

    ERIC Educational Resources Information Center

    Gebbels, Susan; Hunter, Jo; Nunoo, Francis K. E.; Tagoe, E.; Evans, Stewart M.

    2012-01-01

    Pupils aged 12-14 from the University of Ghana Primary and Junior High School conducted studies off the coast adjacent to Accra, including a field visit to explore the effects of climate change on the country's biology, ecology and physical environment. They composed poems and made paintings about the coast and sea as means of conveying their…

  18. Conveying, Assessing, and Learning (Strategies for) Structural Knowledge.

    ERIC Educational Resources Information Center

    Jonassen, David H.; And Others

    Diagrams showing the components of structural knowledge and the theoretical basis for structural knowledge introduce four tables presenting information on: (1) implicit strategies for conveying cognitive structure, including content/structures signalling (Meyer), frames/slots (Armbruster and Anderson), and Elaboration Theory (Reigeluth and…

  19. 21 CFR 1250.51 - Railroad conveyances; discharge of wastes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...; discharge of wastes. (a) New railroad conveyances. Human wastes, garbage, waste water, or other polluting... wastes, garbage, waste water, or other polluting materials that have been suitably treated to prevent the... first time after July 1, 1972, and the terms “waste water or other polluting materials” do not...

  20. PHASE I PILOT AIR CONVEYANCE SYSTEM DESIGN, CLEANING, AND CHARACTERIZATION

    EPA Science Inventory

    The report gives results of a project to develop and refine surface and airborne contamination
    measurement techniques that can be used to evaluate air conveyance system (ACS) cleaning.
    (NOTE: ACS cleaning is advertized to homeowners as a service having a number of benefits...

  1. An Instructional Method Suggestion: Conveying Stories through Origami (Storigami)

    ERIC Educational Resources Information Center

    Oguz, Aysegul

    2016-01-01

    The purpose of this study was to elucidate how to convey stories through origami and suggest its use in education with the help of pre-service elementary teachers' opinions. The participants of the study were 103 elementary teacher candidates from a state university in the 2014-2015 academic year. In this qualitative study, the data were collected…

  2. Wedgethread pipe connection

    DOEpatents

    Watts, John D.

    2003-06-17

    Several embodiments of a wedgethread pipe connection are disclosed that have improved makeup, sealing, and non-loosening characteristics. In one embodiment, an open wedgethread is disclosed that has an included angle measured in the gap between the stab flank and the load flank to be not less than zero, so as to prevent premature wedging between mating flanks before the position of full makeup is reached, as does occur between trapped wedgethreads wherein the included angle is less than zero. The invention may be used for pipe threads large or small, as a flush joint, with collars, screwed into plates or it may even be used to reversibly connect such as solid posts to base members where a wide makeup torque range is desired. This Open wedgethread, as opposed to trapped wedgethreads, provides a threaded pipe connection that: is more cost-effective; can seal high pressure gas; can provide selectively a connection strength as high as the pipe strength; assures easy makeup to the desired position of full makeup within a wide torque range; may have a torque strength as high as the pipe torque strength; is easier to manufacture; is easier to gage; and is less subject to handling damage.

  3. Remotely operated pipe connector

    DOEpatents

    Josefiak, Leonard J.; Cramer, Charles E.

    1988-01-01

    An apparatus for remotely assembling and disassembling a Graylock type coctor between a pipe and a closure for the pipe includes a base and a receptacle on the base for the closure. The pipe is moved into position vertically above the closure by a suitable positioning device such that the flange on the pipe is immediately adjacent and concentric with the flange on the closure. A moving device then moves two semicircular collars from a position free of the closure to a position such that the interior cam groove of each collar contacts the two flanges. Finally, a tensioning device automatically allows remote tightening and loosening of a nut and bolt assembly on each side of the collar to cause a seal ring located between the flanges to be compressed and to seal the closure. Release of the pipe and the connector is accomplished in the reverse order. Preferably, the nut and bolt assembly includes an elongate shaft portion on which a removable sleeve is located.

  4. Low-altitude satellite measurements of pulsating auroral electrons

    NASA Astrophysics Data System (ADS)

    Samara, M.; Michell, R. G.; Redmon, R. J.

    2015-09-01

    We present observations from the Defense Meteorological Satellite Program and Reimei satellites, where common-volume high-resolution ground-based auroral imaging data are available. These satellite overpasses of ground-based all-sky imagers reveal the specific features of the electron populations responsible for different types of pulsating aurora modulations. The energies causing the pulsating aurora mostly range from 3 keV to 20 keV but can at times extend up to 30 keV. The secondary, low-energy electrons (<1 keV) are diminished from the precipitating distribution when there are strong temporal variations in auroral intensity. There are often persistent spatial structures present inside regions of pulsating aurora, and in these regions there are secondary electrons in the precipitating populations. The reduction of secondary electrons is consistent with the strongly temporally varying pulsating aurora being associated with field-aligned currents and hence parallel potential drops of up to 1 kV.

  5. Discovery of X-ray pulsations from a massive star.

    PubMed

    Oskinova, Lidia M; Nazé, Yael; Todt, Helge; Huenemoerder, David P; Ignace, Richard; Hubrig, Swetlana; Hamann, Wolf-Rainer

    2014-01-01

    X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star ξ(1) CMa. This star is a variable of β Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism. PMID:24892504

  6. Constraints on pre-main-sequence evolution from stellar pulsations

    NASA Astrophysics Data System (ADS)

    Casey, M. P.; Zwintz, K.; Guenther, D. B.

    2014-02-01

    Pulsating pre-main-sequence (PMS) stars afford the earliest opportunity in the lifetime of a star to which the concepts of asteroseismology can be applied. PMS stars should be structurally simpler than their evolved counterparts, thus (hopefully!) making any asteroseismic analysis relatively easier. Unfortunately, this isn't necessarily the case. The majority of these stars (around 80) are δ Scuti pulsators, with a couple of γ Doradus, γ Doradus - δ Scuti hybrids, and slowly pulsating B stars thrown into the mix. The majority of these stars have only been discovered within the last ten years, with the community still uncovering the richness of phenomena associated with these stars, many of which defy traditional asteroseismic analysis. A systematic asteroseismic analysis of all of the δ Scuti PMS stars was performed in order to get a better handle on the properties of these stars as a group. Some strange results have been found, including one star pulsating up to the theoretical acoustic cut-off frequency of the star, and a number of stars in which the most basic asteroseismic analysis suggests problems with the stars' positions in the Hertzsprung-Russell diagram. From this we get an idea of the\\break constraints - or lack thereof - that these results can put on PMS stellar evolution.

  7. Large-scale coordinated observations of Pc5 pulsation events

    NASA Astrophysics Data System (ADS)

    Mtumela, Zolile; Walker, Anthony D. M.; Stephenson, Judy A. E.; Kosch, Michael J.

    2016-09-01

    HF (high-frequency) radars belonging to SuperDARN (Super Dual Auroral Radar Network) receive backscatter over substantial fields of view which, when combined, allow for simultaneous returns over extensive regions of the polar caps and midlatitudes. This makes them ideal instruments for the observation of pulsations in the Pc5 (1-5 mHz) frequency band. Relatively few pulsation events observed by multiple radars have been reported in the literature. Here we describe observations of three such events which extend over more than 120° of magnetic longitude in the Northern Hemisphere and one of which is also detected in the Southern Hemisphere. All three events show characteristics of field line resonances. In one case the pulsation has also been observed by magnetometers under or near the radar fields of view. The extensive longitudinal coverage allows accurate determination of azimuthal wave numbers. These are at the upper end of the lower values associated with external sources such as those in the solar wind. Such sources imply antisunward flow. However, the azimuthal wave number is negative, implying westward propagation at magnetic local times on both sides of noon, as would be expected from drift-bounce resonance with positive particles. Quiet conditions and a very low ring current during the events argue against this. The identification of the source of pulsations from a number of different mechanisms remains a problem of interest.

  8. Electron precipitation response to geomagnetic pulsations: Riometer revelation

    NASA Astrophysics Data System (ADS)

    Honary, Farideh; Kavanagh, Andrew

    Electron precipitation modulations by geomagnetic pulsation have been observed in cosmic noise absorption (CNA) as early as 1965 by widebeam riometers (Barcus and Rosenberg, 1965). The first observation of pulsation with high m-number was reported by Kikuchi et al.(1988) em-ploying a scanning narrow-beam riometer to investigate the spatial structure in one dimension with a high resolution. However, the advances in high spatial resolution imaging riometers has provided the ability to observe pulsating cosmic noise absorption with azimuthal wave numbers as high as 380 as well as providing the capability of mapping their structures. These waves are commonly observed during the morning and early afternoon and exhibit eastward propagation. In this presentation a complete generating mechanism for these high m-number waves is dis-cussed as a five step process, beginning with the solar wind as a source for the excitation of dayside magnetospheric cavity modes, mode conversion, energisation of drift-bounce protons by Landau damping, followed by inverse Landau damping as a driving mechanism for the high m number secondary waves that ultimately modulate the electron precipitation. This modulation is observed as pulsations in cosmic noise absorption.

  9. A statistical method for draft tube pressure pulsation analysis

    NASA Astrophysics Data System (ADS)

    Doerfler, P. K.; Ruchonnet, N.

    2012-11-01

    Draft tube pressure pulsation (DTPP) in Francis turbines is composed of various components originating from different physical phenomena. These components may be separated because they differ by their spatial relationships and by their propagation mechanism. The first step for such an analysis was to distinguish between so-called synchronous and asynchronous pulsations; only approximately periodic phenomena could be described in this manner. However, less regular pulsations are always present, and these become important when turbines have to operate in the far off-design range, in particular at very low load. The statistical method described here permits to separate the stochastic (random) component from the two traditional 'regular' components. It works in connection with the standard technique of model testing with several pressure signals measured in draft tube cone. The difference between the individual signals and the averaged pressure signal, together with the coherence between the individual pressure signals is used for analysis. An example reveals that a generalized, non-periodic version of the asynchronous pulsation is important at low load.

  10. Discovery of X-ray pulsations from a massive star.

    PubMed

    Oskinova, Lidia M; Nazé, Yael; Todt, Helge; Huenemoerder, David P; Ignace, Richard; Hubrig, Swetlana; Hamann, Wolf-Rainer

    2014-06-03

    X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star ξ(1) CMa. This star is a variable of β Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism.

  11. On multifractality and synchronization of nonlinear stellar pulsators

    NASA Astrophysics Data System (ADS)

    Bhatraju, Naveen K.; Das, M. K.

    2014-07-01

    Simple models of nonlinear stellar pulsation, whose temporal behavior may reproduce some of the observed features of different classes of variable stars, have been studied. The temporal behavior of dynamical variables of these models exhibits a cascade of period doubling chaos, depending on the specific values of the various control parameters. A multifractal detrended fluctuation analysis (MFDFA) method is further used to identify the scaling behavior of such synthetic time series. The MFDFA of the considered time series, for various models of nonlinear stellar pulsation, shows that the observed multifractal nature is due to long-range correlations. The pulsating star with increased nonadiabaticity and the star with increased convective luminosity, as represented by the simulated data, is shown to possess a strange attractor with noninteger correlation dimension that lies between 2-3. Also the problem of synchronization in coupled nonlinear pulsation models has been investigated using permutation entropy—a complexity measure of the system. The computed order parameter, Γ, representing the correlation of computed permutation entropy for different segments of the simulated time series of displacement of two nonidentical oscillators, has been further used to find the critical coupling parameter for general synchronization of the oscillators.

  12. Heat pipes and use of heat pipes in furnace exhaust

    DOEpatents

    Polcyn, Adam D.

    2010-12-28

    An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

  13. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W. Thor; Appel, D. Keith; Lewis, Gregory W.

    1995-01-01

    A method and apparatus for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher.

  14. Apparatus for moving a pipe inspection probe through piping

    DOEpatents

    Zollinger, W.T.; Appel, D.K.; Lewis, G.W.

    1995-07-18

    A method and apparatus are disclosed for controllably moving devices for cleaning or inspection through piping systems, including piping systems with numerous piping bends therein, by using hydrostatic pressure of a working fluid introduced into the piping system. The apparatus comprises a reservoir or other source for supplying the working fluid to the piping system, a launch tube for admitting the device into the launcher and a reversible, positive displacement pump for controlling the direction and flow rate of the working fluid. The device introduced into the piping system moves with the flow of the working fluid through the piping system. The launcher attaches to the valved ends of a piping system so that fluids in the piping system can recirculate in a closed loop. The method comprises attaching the launcher to the piping system, supplying the launcher with working fluid, admitting the device into the launcher, pumping the working fluid in the direction and at the rate desired so that the device moves through the piping system for pipe cleaning or inspection, removing the device from the launcher, and collecting the working fluid contained in the launcher. 8 figs.

  15. Composite drill pipe

    DOEpatents

    Leslie, James C.; Leslie, II, James C.; Heard, James; Truong, Liem , Josephson; Marvin , Neubert; Hans

    2008-12-02

    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  16. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W. Thor; Appel, D. Keith; Park, Larry R.

    1995-01-01

    An inspection rabbit for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON.RTM.). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system.

  17. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics. PMID:24067709

  18. Apparatus for inspecting piping

    DOEpatents

    Zollingger, W.T.; Appel, D.K.; Park, L.R.

    1995-03-21

    An inspection rabbit is described for inspecting piping systems having severe bends therein. The rabbit consists of a flexible, modular body containing a miniaturized eddy current inspection probe, a self-contained power supply for proper operation of the rabbit, an outer surface that allows ease of movement through piping systems and means for transmitting data generated by the inspection device. The body is preferably made of flexible polyvinyl chloride (PVC) tubing or, alternatively, silicone rubber with a shrink wrapping of polytetrafluoroethylene (TEFLON{trademark}). The body is formed to contain the power supply, preferably a plurality of batteries, and a spool of communication wire that connects to a data processing computer external to the piping system. 6 figures.

  19. Heat Pipe Technology

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  20. Heat-pipe Earth.

    PubMed

    Moore, William B; Webb, A Alexander G

    2013-09-26

    The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics.

  1. Poloidal monochromatic pulsations in Pc4-5 range observed in the Earth magnetosphere

    NASA Astrophysics Data System (ADS)

    Belakhovsky, Vladimir

    Poloidal monochromatic pulsations in Pc4-5 range observed in the Earth magnetosphere Belakhovsky V.B.1, Pilipenko V.A.2 1 - Polar Geophysical Institute, Apatity, Russia 2 - Institute of Physics of the Earth, Moscow, Russia Monochromatic geomagnetic pulsations in the Pc4-5 frequency range in the morning sector for some events in 2007-2008 years were studied using GOES, THEMIS, and ETS spacecrafts. The satellite observations showed that these pulsations are a poloidal-type fundamental mode of Alfven field line oscillations with the dominant radial and field-aligned magnetic components. The observed pulsations are small-scale in azimuthal direction; it excited during the low geomagnetic activity and are quite similar to Pg type pulsations. Contrary to typical Pg, these pulsations practically cannot be seen on the CARISMA magnetometers. The observed magnetic pulsations were accompanied by the simultaneous pulsations in the fluxes of energetic electrons and protons, as seen by LANL satellites with a great modulation depth. A strong increase of the electron density in the magnetosphere was found before the onset of the geomagnetic pulsations. As seen by THEMIS satellites these pulsations propagate in sunward direction, i.e. in the direction of electron drift in the morning sector. We suppose that the injection of energetic electrons may be responsible for the excitation of the poloidal Pc4-5 pulsations at the morning flank of the magnetosphere, though specific excitation mechanism is still unknown.

  2. Radial and Nonradial Pulsations in Hot White Dwarfs -- Cycle 3 Medium

    NASA Astrophysics Data System (ADS)

    Kawaler, Steven

    1992-06-01

    We propose to use the High Speed Photometer to search for the previously unobserved phenomenon of RADIAL pulsations in white dwarfs. Three classes of NONRADIALLY pulsating white dwarfs are known, with pulsation periods ranging from several minutes to half an hour. Theory predicts that stars slightly hotter than the nonradial instability strips for DA, DB, and PG 1159-type white dwarfs should be unstable to radial pulsations, with periods between 0.1 and 10 seconds. We have received Cycle 2 HSP time to search several DA and DB candidates for these predicted rapid pulsations. In Cycle 3 we propose to use HSP to search for the predicted radial pulsations in 3 members of the PG 1159 class. High-speed UV photometry is free from atmospheric scintillation, and takes advantage of the larger stellar fluxes and larger pulsation amplitudes for these extremely hot (above 125,000 K) stars. Our targets are three known nonradial pulsators (two are central stars in planetary nebulae), so that the observations will also provide information on the wavelength dependence of the nonradial pulsation amplitudes. The presence (or absence) of radial pulsations will provide significant new information for (or challenges to) our understanding of white-dwarf pulsations, structure, and evolution.

  3. Superfluid Helium Heat Pipe

    NASA Astrophysics Data System (ADS)

    Gully, P.

    This paper reports on the development and the thermal tests of three superfluid helium heat pipes. Two of them are designed to provide a large transport capacity (4 mW at 1.7 K). They feature a copper braid located inside a 6 mm outer diameter stainless tube fitted with copper ends for mechanical anchoring. The other heat pipe has no copper braid and is designed to get much smaller heat transport capacity (0.5 mW) and to explore lower temperature (0.7 - 1 K). The copper braid and the tube wall is the support of the Rollin superfluid helium film in which the heat is transferred. The low filling pressure makes the technology very simple with the possibility to easily bend the tube. We present the design and discuss the thermal performance of the heat pipes tested in the 0.7 to 2.0 K temperature range. The long heat pipe (1.2 m with copper braid) and the short one (0.25 m with copper braid) have similar thermal performance in the range 0.7 - 2.0 K. At 1.7 K the long heat pipe, 120 g in weight, reaches a heat transfer capacity of 6.2 mW and a thermal conductance of 600 mW/K for 4 mW transferred power. Due to the pressure drop of the vapor flow and Kapitza thermal resistance, the conductance of the third heat pipe dramatically decreases when the temperature decreases. A 3.8 mW/K is obtained at 0.7 K for 0.5 mW transferred power.

  4. Pseudo-nonlinear dynamic analysis of buckled pipes

    NASA Astrophysics Data System (ADS)

    Gültekin Sınır, B.

    2013-02-01

    In this study, the post-divergence behavior of fluid-conveying pipes supported at both ends is investigated using the nonlinear equations of motion. The governing equation exhibits a cubic nonlinearity arising from mid-plane stretching. Exact solutions for post-buckling configurations of pipes with fixed-fixed, fixed-hinged, and hinged-hinged boundary conditions are investigated. The pipe is stable at its original static equilibrium position until the flow velocity becomes high enough to cause a supercritical pitchfork bifurcation, and the pipe loses stability by static divergence. In the supercritical fluid velocity regime, the equilibrium configuration becomes unstable and bifurcates into multiple equilibrium positions. To investigate the vibrations that occur in the vicinity of a buckled equilibrium position, the pseudo-nonlinear vibration problem around the first buckled configuration is solved precisely using a new solution procedure. By solving the resulting eigenvalue problem, the natural frequencies and the associated mode shapes of the pipe are calculated. The dynamic stability of the post-buckling configurations obtained in this manner is investigated. The first buckled shape is a stable equilibrium position for all boundary conditions. The buckled configurations beyond the first buckling mode are unstable equilibrium positions. The natural frequencies of the lowest vibration modes around each of the first two buckled configurations are presented. Effects of the system parameters on pipe behavior as well as the possibility of a subcritical pitchfork bifurcation are also investigated. The results show that many internal resonances might be activated among the vibration modes around the same or different buckled configurations.

  5. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C.

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  6. On the Polarization Properties of Magnetar Giant Flare Pulsating Tails

    NASA Astrophysics Data System (ADS)

    Yang, Yuan-Pei; Zhang, Bing

    2015-12-01

    Three giant flares have been detected so far from soft gamma-ray repeaters, each characterized by an initial short hard spike and a pulsating tail. The observed pulsating tails are characterized by a duration of ˜100 s, an isotropic energy of ˜1044 erg, and a pulse period of a few seconds. The pulsating tail emission likely originates from the residual energy after the intense energy release during the initial spike, which forms a trapped fireball composed of a photon-pair plasma in a closed-field-line region of the magnetars. Observationally the spectra of pulsating tails can be fitted by the superposition of a thermal component and a power-law component, with the thermal component dominating the emission in the early and late stages of the pulsating-tail observations. In this paper, assuming that the trapped fireball is from a closed-field-line region in the magnetosphere, we calculate the atmospheric structure of the optically thick trapped fireball and the polarization properties of the trapped fireball. By properly treating the photon propagation in a hot, highly magnetized, electron-positron pair plasma, we tally photons in two modes (O mode and E mode) at a certain observational angle through Monte Carlo simulations. Our results suggest that the polarization degree depends on the viewing angle with respect to the magnetic axis of the magnetar, and can be as high as Π ≃ 30% in the 1-30 keV band, and Π ≃ 10% in the 30-100 keV band, if the line of sight is perpendicular to the magnetic axis.

  7. Kappa effect pulsational instability for hot extreme helium stars

    SciTech Connect

    Cox, A.N.

    1990-01-01

    A long standing problem for the hydrogen deficient stars has been the mechanism for the pulsation instability for the hottest members of this class. The usual {kappa} mechanism works well for stars that are in the hydrogen and helium ionization instability strip, and this strip extends to perhaps 20,000K at high luminosity. However, several stars are definitely hotter. Investigations for another ionization instability strip, such as for carbon, have always shown that there is not enough carbon to produce a rapid enough increase of opacity with temperature to give the well-known {kappa} effect. This is so even though these hydrogen deficient stars do show enhanced carbon in their spectra. A strong stellar wind can produce the observed hydrogen deficiency. Another popular mechanism is mass loss in a binary system through the Roche lobe. It now is possible that the missing pulsational instability mechanism is the rapid increase of iron lines absorption as the temperature increases above about 150,000K in the low density envelopes of these luminous stars. Recent calculations shows that the n = 3 to n = 3 transitions in iron that were assumed unimportant in the earlier Los Alamos calculations can double or triple the opacity suddenly as the iron lines appear in a very sensitive part of the spectrum of the diffusing photons. It has been proposed that these iron lines also cause the many varieties of normal B star pulsations, and the hydrogen deficient stars are merely another example of this new {kappa} effect for pulsating stars. The extreme helium star V2076 Oph at 31,900K, and 38,900 L{sub {circle dot}} for a mass of 1.4 M{sub {circle dot}} pulsates in the radial fundamental model at about 1 day period with a very large linear growth rate when the iron lines more than double the opacity, but is stable otherwise.

  8. ON THE POLARIZATION PROPERTIES OF MAGNETAR GIANT FLARE PULSATING TAILS

    SciTech Connect

    Yang, Yuan-Pei; Zhang, Bing E-mail: zhang@physics.unlv.edu

    2015-12-10

    Three giant flares have been detected so far from soft gamma-ray repeaters, each characterized by an initial short hard spike and a pulsating tail. The observed pulsating tails are characterized by a duration of ∼100 s, an isotropic energy of ∼10{sup 44} erg, and a pulse period of a few seconds. The pulsating tail emission likely originates from the residual energy after the intense energy release during the initial spike, which forms a trapped fireball composed of a photon-pair plasma in a closed-field-line region of the magnetars. Observationally the spectra of pulsating tails can be fitted by the superposition of a thermal component and a power-law component, with the thermal component dominating the emission in the early and late stages of the pulsating-tail observations. In this paper, assuming that the trapped fireball is from a closed-field-line region in the magnetosphere, we calculate the atmospheric structure of the optically thick trapped fireball and the polarization properties of the trapped fireball. By properly treating the photon propagation in a hot, highly magnetized, electron–positron pair plasma, we tally photons in two modes (O mode and E mode) at a certain observational angle through Monte Carlo simulations. Our results suggest that the polarization degree depends on the viewing angle with respect to the magnetic axis of the magnetar, and can be as high as Π ≃ 30% in the 1–30 keV band, and Π ≃ 10% in the 30–100 keV band, if the line of sight is perpendicular to the magnetic axis.

  9. Heat transfer in pipes

    NASA Technical Reports Server (NTRS)

    Burbach, T.

    1985-01-01

    The heat transfer from hot water to a cold copper pipe in laminar and turbulent flow condition is determined. The mean flow through velocity in the pipe, relative test length and initial temperature in the vessel were varied extensively during tests. Measurements confirm Nusselt's theory for large test lengths in laminar range. A new equation is derived for heat transfer for large starting lengths which agrees satisfactorily with measurements for large starting lengths. Test results are compared with the new Prandtl equation for heat transfer and correlated well. Test material for 200- and to 400-diameter test length is represented at four different vessel temperatures.

  10. Pipe Drafting with CAD. Teacher Edition.

    ERIC Educational Resources Information Center

    Smithson, Buddy

    This teacher's guide contains nine units of instruction for a course on computer-assisted pipe drafting. The course covers the following topics: introduction to pipe drafting with CAD (computer-assisted design); flow diagrams; pipe and pipe components; valves; piping plans and elevations; isometrics; equipment fabrication drawings; piping design…

  11. Radial Stellar Pulsation and Three-dimensional Convection. II. Two-dimensional Convection in Full Amplitude Radial Pulsation

    NASA Astrophysics Data System (ADS)

    Geroux, Chris M.; Deupree, Robert G.

    2013-07-01

    We have developed a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and radial pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light curves. Previous multi-dimensional calculations were prevented from reaching full amplitude because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We have removed this difficulty by defining our radial coordinate flow algorithm to require that the mass in a spherical shell remain constant for every time step throughout the pulsation cycle. We have used our new code to perform two-dimensional (2D) simulations of the interaction of radial pulsation and convection. We have made comparisons between light curves from our 2D convective simulations with observed light curves and find that our 2D simulated light curves are better able to match the observed light curve shape near the red edge of the RR Lyrae instability strip than light curves from previous one-dimensional time-dependent convective models.

  12. Fast modulations of pulsating proton aurora related to subpacket structures of Pc1 geomagnetic pulsations at subauroral latitudes

    DOE PAGES

    Ozaki, M.; Shiokawa, K.; Miyoshi, Y.; Kataoka, R.; Yagitani, S.; Inoue, T.; Ebihara, Y.; Jun, C. -W; Nomura, R.; Sakaguchi, K.; et al

    2016-08-14

    To understand the role of electromagnetic ion cyclotron (EMIC) waves in determining the temporal features of pulsating proton aurora (PPA) via wave-particle interactions at subauroral latitudes, high-time-resolution (1/8 s) images of proton-induced N2>+ emissions were recorded using a new electron multiplying charge-coupled device camera, along with related Pc1 pulsations on the ground. The observed Pc1 pulsations consisted of successive rising-tone elements with a spacing for each element of 100 s and subpacket structures, which manifest as amplitude modulations with a period of a few tens of seconds. In accordance with the temporal features of the Pc1 pulsations, the auroral intensitymore » showed a similar repetition period of 100 s and an unpredicted fast modulation of a few tens of seconds. Furthermore, these results indicate that PPA is generated by pitch angle scattering, nonlinearly interacting with Pc1/EMIC waves at the magnetic equator.« less

  13. RADIAL STELLAR PULSATION AND THREE-DIMENSIONAL CONVECTION. II. TWO-DIMENSIONAL CONVECTION IN FULL AMPLITUDE RADIAL PULSATION

    SciTech Connect

    Geroux, Chris M.; Deupree, Robert G.

    2013-07-10

    We have developed a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and radial pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light curves. Previous multi-dimensional calculations were prevented from reaching full amplitude because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We have removed this difficulty by defining our radial coordinate flow algorithm to require that the mass in a spherical shell remain constant for every time step throughout the pulsation cycle. We have used our new code to perform two-dimensional (2D) simulations of the interaction of radial pulsation and convection. We have made comparisons between light curves from our 2D convective simulations with observed light curves and find that our 2D simulated light curves are better able to match the observed light curve shape near the red edge of the RR Lyrae instability strip than light curves from previous one-dimensional time-dependent convective models.

  14. Effects of self-pulsation on the spray characteristics of gas-liquid swirl coaxial injector

    NASA Astrophysics Data System (ADS)

    Kang, Zhongtao; Li, Qinglian; Cheng, Peng; Zhang, Xinqiao; Wang, Zhen-guo

    2016-10-01

    To understand the influence of self-pulsation on the spray characteristics of gas-liquid swirl coaxial injector, a back-lighting photography technique has been employed to capture the instantaneous self-pulsated spray and stable spray images with a high speed camera. The diameter and velocity of the droplets in the spray have been characterized with a Dantec Phase Doppler Anemometry (PDA) system. The effects of self-pulsation on the spray pattern, primary breakup, spray angle, diameter and velocity distribution and mass flow rate distribution are analyzed and discussed. The results show that the spray morphology is greatly influenced by self-pulsation. The stable spray has a cone shape, while the self-pulsated spray looks like a Christmas tree. The main difference of these two sprays is the primary breakup. The liquid film of stable spray keeps stable while that of self-pulsated spray oscillates periodically. The film width of self-pulsated spray varies in a large range with 'neck' and 'shoulder' features existing. The liquid film of self-pulsated spray breaks up at the second neck, and then the second shoulder begins to breakup into ligaments. The self-pulsated spray produces droplet clusters periodically, varies horizontal spray width and mass flux periodically. From the point of spatial distribution, self-pulsation is good for the spray, it uniformizes the mass flux along radius and increases the spray angle. However, when self-pulsation occurs, the SMD distribution varies from an inverted V shape to a hollow cone shape, and SMD increases at all the measuring points. Namely, from the point of atomization performance, self-pulsation has negative effects even when the breakup length is smaller. The effects of self-pulsation on the diameter and velocity distributions of the spray are mainly in the center part of the spray. The periphery of stable and self-pulsated spray has similar diameter and velocity distribution.

  15. Flat-plate heat pipe

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Fleischman, G. L. (Inventor)

    1977-01-01

    Flat plate (vapor chamber) heat pipes were made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3 to 5 C over the panel surface.

  16. Reusable high-temperature heat pipes and heat pipe panels

    NASA Technical Reports Server (NTRS)

    Camarda, Charles J. (Inventor); Ransone, Philip O. (Inventor)

    1989-01-01

    A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.

  17. Nanomaterial modifications on conductivity of coal conveyer belt

    SciTech Connect

    Zhang, J.C.; Zhang, Y.G.; Wang, T.T.; Yang, L.F.; Liu, S.M.; Yang, D.H.; Zhang, M.; Gao, X.

    2008-08-15

    By analyzing the macro electrical properties and the microscopic structure from SEM of nanomaterials modified mine transmission belt samples. The influences of the filling process of inorganic nano particle-filled rubber and PVC polymer on the physical properties of coal transmission belt is reviewed, as well as PTC and NTC effect on the stability of the physical properties and stability of materials. Influence of nano-materials and polymer materials for rubber and temperature changes in the plastic filled refining process. Crosslinker and major filler changes in the amount and filled plastic chain time on the conductivity of coal conveyer belt is studied. Influence of cure temperature. Cure time on the mechanical performance is studied. The microscopic mechanism of macro conductivity change of conveyer belt is discussed.

  18. Heat pipe investigations

    NASA Technical Reports Server (NTRS)

    Marshburn, J. P.

    1973-01-01

    Techniques associated with thermal-vacuum and bench testing, along with flight testing of the OAO-C spacecraft heat pipes are outlined, to show that the processes used in heat transfer design and testing are adequate for good performance evaluations.

  19. Aeronautical tubes and pipes

    NASA Astrophysics Data System (ADS)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  20. Numerical study of vertical pneumatic conveying: Effect of friction coefficient

    NASA Astrophysics Data System (ADS)

    Li, K.; Kuang, S. B.; Zou, R. P.; Pan, R. H.; Yu, A. B.

    2013-06-01

    This paper presents a numerical study of vertical pneumatic conveying by a combined approach of computational fluid dynamics for gas phase and discrete element method for solid phase. The effects of friction coefficient on the flows in regard with particle flow patterns and their transition, reverse flow, and gas pressure behavior are qualified. The forces acting on particles are analyzed in detail to understand the underlying mechanisms.

  1. The Use of Haiku to Convey Complex Concepts in Neuroscience

    PubMed Central

    Pollack, Alexia E.; Korol, Donna L.

    2013-01-01

    Conveying scientific content with accuracy and fluency takes practice and requires deep understanding of the concepts being conveyed. This depth of knowledge comes from internalizing information and constructing it into a form that is unique and coherent to the individual. Often in science classrooms there is little or no opportunity for students to practice this type of thinking, activities that we believe are fundamental to effective science communication. This article describes the use of haiku – a 17 syllable poem – as a means for students to convey neurobiological concepts in a succinct manner by forcing them to focus on the most salient features of the observed processes. In our assignments haiku writing was successfully paired with explanations of the students’ thought processes (Addiction course) or the scientific evidence to support claims (Neurodegenerative Disease course). We provide examples of student haiku and explanations as evidence of the power of this approach. The coupling of poetry and prose together create rich, accurate descriptions of scientific phenomena by encouraging higher-order thinking. Poetry writing can thus be used across the curriculum to forge comprehension of complex ideas in any discipline and to bridge the arts and the sciences. PMID:24319390

  2. Heat Pipes Cool Power Magnetics

    NASA Technical Reports Server (NTRS)

    Hansen, I.; Chester, M.; Luedke, E.

    1983-01-01

    Configurations originally developed for space use are effective in any orientation. Heat pipes integrated into high-power, high-frequency, highvoltage spaceflight magnetics reduce weight and improve reliability by lowering internal tempertures. Two heat pipes integrated in design of power transformer cool unit in any orientation. Electrostatic shield conducts heat from windings to heat pipe evaporator. Technology allows dramatic reductions in size and weight, while significantly improving reliability. In addition, all attitude design of heat pipes allows operation of heat pipes independent of local gravity forces.

  3. Features of Pc5 pulsations in the geomagnetic field, auroral luminosity, and Riometer absorption

    NASA Astrophysics Data System (ADS)

    Belakhovsky, V. B.; Pilipenko, V. A.; Samsonov, S. N.; Lorentsen, D.

    2016-01-01

    Simultaneous morning Pc5 pulsations ( f ~ 3-5 mHz) in the geomagnetic field, aurora intensities (in the 557.7 and 630.0 nm oxygen emissions and the 471.0 nm nitrogen emission), and riometer absorption, were studied based on the CARISMA, CANMOS, and NORSTAR network data for the event of January 1, 2000. According to the GOES-8 satellite observations, these Pc5 geomagnetic pulsations are observed as incompressible Alfvén waves with toroidal polarization in the magnetosphere. Although the Pc5 pulsation frequencies in auroras, the geomagnetic field, and riometer absorption are close to one another, stable phase relationships are not observed between them. Far from all trains of geomagnetic Pc5 pulsations are accompanied by corresponding auroral pulsations; consequently, geomagnetic pulsations are primary with respect to auroral pulsations. Both geomagnetic and auroral pulsations propagate poleward, and the frequency decreases with increasing geomagnetic latitude. When auroral Pc5 pulsations appear, the ratio of the 557.7/630.0 nm emission intensity sharply increases, which indicates that auroral pulsations result from not simply modulated particle precipitation but also an additional periodic acceleration of auroral electrons by the wave field. A high correlation is not observed between Pc5 pulsations in auroras and the riometer absorption, which indicates that these pulsations have a common source but different generation mechanisms. Auroral luminosity modulation is supposedly related to the interaction between Alfvén waves and the region with the field-aligned potential drop above the auroral ionosphere, and riometer absorption modulation is caused by the scattering of energetic electrons by VLF noise pulsations.

  4. Red-Line (630nm) Pulsating Auroras And Their Possible Magnetospheric Driver

    NASA Astrophysics Data System (ADS)

    Liang, J.; Donovan, E.; Zhang, X.; Spanswick, E.; Gillies, M.; Jackel, B. J.

    2015-12-01

    Pulsating auroras are usually known to be led by the precipitation of energetic electrons from the central plasma sheet, and are thus often displayed in blue-line and/or green-line auroral emission lines. In this study we report the observations of 630nm oxygen red-line auroras by REGO imager, and explore their possible underlying mechanisms. Upon inspecting the temporal/spatial pattern of the red-line pulsating auroras and comparing with concurrent/collocated observations from THEMIS and RAINBOW imagers, we distinguish two types of red-line pulsating auroras. In one type of red-line pulsating aurora, the emission is weak in intensity, but its pulsation is synchronous with that of the collocated green-line pulsating aurora. The other type of red-line pulsating aurora is fairly strong in intensity, but its temporal pattern contains much longer-period components as compared to the green-line pulsating aurora. In both types of pulsating auroras, the spatial dimension and motion speed of the red- and green-line auroral patches are rather comparable. We suggest that the first type of red-line pulsating aurora is caused by secondary electrons and/or a cascading excitation of O(1D) as the byproduct of the primary electron precipitation (and the resulting green-line emission), while the second type of red-line pulsating aurora is directly led by the low-energy part (hundreds of eV) of the electron precipitation in the lower F-region ionosphere. In the latter regard, we present in-situ RBSP observations conjugate to the pulsating auroral patches in a few events, and explore a potential relationship between the red-line pulsating aurora and the electron cyclotron harmonic (ECH) wave, which is capable of scattering the low-energy electrons into the loss-cone in the inner magnetosphere.

  5. The occurrence of non-pulsating stars in the γ Dor and δ Sct pulsation instability regions: Results from Kepler quarter 14–17 data

    DOE PAGES

    Guzik, J. A.; Bradley, P. A.; Jackiewicz, J.; Molenda-Zakowicz, J.; Uytterhoeven, K.; Kinemuchi, K.

    2015-04-21

    In this study, the high precision long time-series photometry of the NASA Kepler spacecraft provides an excellent means to discover and characterize variability in main-sequence stars, and to make progress in interpreting the pulsations to derive stellar interior structure and test stellar models. For stars of spectral types A–F, the Kepler data revealed a number of surprises, such as more hybrid pulsating Sct and Dor pulsators than expected, pulsators lying outside of the instability regions predicted by theory, and stars that were expected to pulsate, but showed no variability. In our 2013 Astronomical Review article, we discussed the statistics ofmore » variability for 633 faint (Kepler magnitude 14–16) spectral type A–F stars observed by Kepler during Quarters 6–13 (June 2010–June 2012).« less

  6. The occurrence of non-pulsating stars in the γ Dor and δ Sct pulsation instability regions: Results from Kepler quarter 14–17 data

    SciTech Connect

    Guzik, J. A.; Bradley, P. A.; Jackiewicz, J.; Molenda-Zakowicz, J.; Uytterhoeven, K.; Kinemuchi, K.

    2015-04-21

    In this study, the high precision long time-series photometry of the NASA Kepler spacecraft provides an excellent means to discover and characterize variability in main-sequence stars, and to make progress in interpreting the pulsations to derive stellar interior structure and test stellar models. For stars of spectral types A–F, the Kepler data revealed a number of surprises, such as more hybrid pulsating Sct and Dor pulsators than expected, pulsators lying outside of the instability regions predicted by theory, and stars that were expected to pulsate, but showed no variability. In our 2013 Astronomical Review article, we discussed the statistics of variability for 633 faint (Kepler magnitude 14–16) spectral type A–F stars observed by Kepler during Quarters 6–13 (June 2010–June 2012).

  7. 76 FR 44402 - Proposed Information Collection (Application for Automobile or Other Conveyance and Adaptive...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ... AFFAIRS Proposed Information Collection (Application for Automobile or Other Conveyance and Adaptive...' eligibility for automobile adaptation equipment or other conveyance allowance. DATES: Written comments and... techniques or the use of other forms of information technology. Title: Application for Automobile or...

  8. HST observations of the pulsating white dwarf GD 358

    NASA Astrophysics Data System (ADS)

    Castanheira, B. G.; Nitta, A.; Kepler, S. O.; Winget, D. E.; Koester, D.

    2005-03-01

    We used time-resolved ultraviolet spectroscopy obtained with the FOS and STIS spectrographs of the Hubble Space Telescope (HST), together with archival IUE observations to measure the effective temperature (Teff), surface gravity (log g) and distance (d) of the pulsating DB white dwarf GD 358 with unprecedented accuracy, and to show that the temperature did not change during the 1996 sforzando, when the star changed basically to a single mode pulsator. We also measured for the first time for a DBV the spherical harmonic degree (ℓ) for two modes, with k=8 and k=9, which was only possible because the stellar light curve was dominated by a single mode in 1996. The independent spectra provide the following values: Teff=24 100± 400 K, log g=7.91±0.26 and d=42.7±2.5 pc. The ultraviolet spectroscopic distance is in better agreement with the seismological value, than the one derived by parallax.

  9. Comparative pulsation calculations with OP and OPAL opacities

    NASA Technical Reports Server (NTRS)

    Kanbur, Shashi M.; Simon, Norman R.

    1994-01-01

    Comparative linear nonadiabatic pulsation calculations are presented using the OPAL and Opacity Project opacities. The two sets of opacities include effects due to intermediate coupling and fine structure as well as new abundances. We used two mass luminosity (M-L) relations, one standard (BIT), and one employing substantial convective core overshoot (COV). The two sets of opacities cannot be differentiated on the basis of the stellar pulsation calculations presented here. The BIT relation can model the beat and bump Cepheids with masses between 4 and 7 solar mass, while if the overshoot relation is used, masses between 2 and 6 solar mass are required. In the RR Lyrae regime, we find the inferred masses of globular cluster RRd stars to be little influenced by the choice of OPAL or OP. Finally, the limited modeling we have done is not able to constrain the Cepheid M-L relation based upon period ratios observed in the beat and bump stars.

  10. The unique dynamical system underlying RR Lyrae pulsations

    NASA Astrophysics Data System (ADS)

    Kollath, Z.

    2016-05-01

    Hydrodynamic models of RR Lyrae pulsation display a very rich behaviour. Contrary to earlier expectations, high order resonances play a crucial role in the nonlinear dynamics representing the interacting modes. Chaotic attractors can be found at different time scales: both in the pulsation itself and in the amplitude equations shaping the possible modulation of the oscillations. Although there is no one-to-one connection between the nonlinear features found in the numerical models and the observed behaviour, the richness of the found phenomena suggests that the interaction of modes should be taken seriously in the study of the still unsolved puzzle of Blazhko effect. One of the main lessons of this complex system is that we should rethink the simple interpretation of the observed effect of resonances.

  11. Are two-fluid effects relevant to ULF pulsations?

    NASA Astrophysics Data System (ADS)

    Wright, Andrew N.; Allan, W.

    1996-11-01

    It has been suggested recently that the traditional single-fluid MHD description of ULF pulsations is wrong and that a two-fluid model (which includes electron inertia) is required [Bellan, 1994]. If this claim is correct, it suggests most previous studies are inadequate and of questionable value. We have examined the appropriate equations and find that two-fluid effects are not important for typical ULF pulsations. Specifically, the time taken to develop spatial scales similar to the electron inertia length far exceeds the lifetime of the waves. We argue that the singular normal modes of single-fluid MHD are important properties of the magnetospheric system that should be studied. They may be employed to calculate the evolution of waves and are also a useful mathematical limit of the more realistic dissipative normal modes.

  12. SEISMOLOGY OF A MASSIVE PULSATING HYDROGEN ATMOSPHERE WHITE DWARF

    SciTech Connect

    Kepler, S. O.; Pelisoli, Ingrid; Pecanha, Viviane; Costa, J. E. S.; Fraga, Luciano; Hermes, J. J.; Winget, D. E.; Castanheira, Barbara; Corsico, A. H.; Romero, A. D.; Althaus, Leandro; Kleinman, S. J.; Nitta, A.; Koester, D.; Kuelebi, Baybars; Kanaan, Antonio

    2012-10-01

    We report our observations of the new pulsating hydrogen atmosphere white dwarf SDSS J132350.28+010304.22. We discovered periodic photometric variations in frequency and amplitude that are commensurate with nonradial g-mode pulsations in ZZ Ceti stars. This, along with estimates for the star's temperature and gravity, establishes it as a massive ZZ Ceti star. We used time-series photometric observations with the 4.1 m SOAR Telescope, complemented by contemporary McDonald Observatory 2.1 m data, to discover the photometric variability. The light curve of SDSS J132350.28+010304.22 shows at least nine detectable frequencies. We used these frequencies to make an asteroseismic determination of the total mass and effective temperature of the star: M{sub *} = 0.88 {+-} 0.02 M{sub Sun} and T{sub eff} = 12, 100 {+-} 140 K. These values are consistent with those derived from the optical spectra and photometric colors.

  13. Quantitative results of stellar evolution and pulsation theories.

    NASA Technical Reports Server (NTRS)

    Fricke, K.; Stobie, R. S.; Strittmatter, P. A.

    1971-01-01

    The discrepancy between the masses of Cepheid variables deduced from evolution theory and pulsation theory is examined. The effect of input physics on evolutionary tracks is first discussed; in particular, changes in the opacity are considered. The sensitivity of pulsation masses to opacity changes and to the ascribed values of luminosity and effective temperature are then analyzed. The Cepheid mass discrepancy is discussed in the light of the results already obtained. Other astronomical evidence, including the mass-luminosity relation for main sequence stars, the solar neutrino flux, and cluster ages are also considered in an attempt to determine the most likely source of error in the event that substantial mass loss has not occurred.

  14. Pulsating aurora induced by upper atmospheric barium releases

    NASA Technical Reports Server (NTRS)

    Deehr, C.; Romick, G.

    1977-01-01

    The paper reports the apparent generation of pulsating aurora by explosive releases of barium vapor near 250 km altitude. This effect occurred only when the explosions were in the path of precipitating electrons associated with the visible aurora. Each explosive charge was a standard 1.5 kg thermite mixture of Ba and CuO with an excess of Ba metal which was vaporized and dispersed by the thermite explosion. Traces of Sr, Na, and Li were added to some of the charges, and monitoring was achieved by ground-based spectrophotometric observations. On March 28, 1976, an increase in emission at 5577 A and at 4278 A was observed in association with the first two bursts, these emissions pulsating with roughly a 10 sec period for approximately 60 to 100 sec after the burst.

  15. Self-Sustained Ultrafast Pulsation in Coupled VCSELs

    NASA Technical Reports Server (NTRS)

    Ning, Cun-Zheng

    2001-01-01

    High frequency, narrow-band self-pulsating operation is demonstrated in two coupled vertical-cavity surface-emitting lasers (VCSELs). The coupled VCSELs provide an ideal source for high-repetition rate (over 40 GHz), sinusoidal-like modulated laser source with Gaussian-like near- and far-field profiles. We also show that the frequency of the modulation can be tuned by the inter-VCSEL separation or by DC-bias level.

  16. Mapping correlated membrane pulsations and fluctuations in human cells.

    PubMed

    Pelling, Andrew E; Veraitch, Farlan S; Pui-Kei Chu, Carol; Nicholls, Brian M; Hemsley, Alexandra L; Mason, Chris; Horton, Michael A

    2007-01-01

    The cell membrane and cytoskeleton are dynamic structures that are strongly influenced by the thermo-mechanical background in addition to biologically driven mechanical processes. We used atomic force microscopy (AFM) to measure the local membrane motion of human foreskin fibroblasts (HFFs) which were found to be governed by random and non-random correlated mechanical processes. Interphase cells displayed distinct membrane pulsations in which the membrane was observed to slowly contract upwards followed by a recovery to its initial position. These pulsations occurred one to three times per minute with variable amplitudes (20-100 pN) separated by periods of random baseline fluctuations with amplitudes of <20 pN. Cells were exposed to actin and microtubule (MT) destabilizing drugs and induced into early apoptosis. Mechanical pulsations (20-80 pN) were not prevented by actin or MT depolymerization but were prevented in early apoptotic cells which only displayed small amplitude baseline fluctuations (<20 pN). Correlation analysis revealed that the cell membrane motion is largely random; however several non-random processes, with time constants varying between approximately 2 and 35 s are present. Results were compared to measured cardiomyocyte motion which was well defined and highly correlated. Employing automated positioning of the AFM tip, interphase HFF correlation time constants were also mapped over a 10 microm2 area above the nucleus providing some insights into the spatial variability of membrane correlations. Here, we are able to show that membrane pulsations and fluctuations can be linked to physiological state and cytoskeletal dynamics through distinct sets of correlation time constants in human cells.

  17. HST Observations of the Pulsating White Dwarf GD 358

    NASA Astrophysics Data System (ADS)

    Castanheira, B. G.; Kepler, S. O.; Nitta, A.; Winget, D. E.; Koester, D.

    2005-07-01

    We used time-resolved ultraviolet spectroscopy obtained with the FOS and STIS spectrographs of the Hubble Space Telescope (HST), together with archival IUE observations to measure the effective temperature (Teff}), surface gravity (log g) and distance (d) of the pulsating DB white dwarf GD 358 with unprecedented accuracy, and to show the temperature did not change during the 1996 sforzando, when the star changed basically to a single mode pulsator. We also measured, for the first time for a DBV, the spherical harmonic degree (ℓ) for two modes, with k=8 and k=9, which was only possible because the stellar light curve was dominated by a single mode in 1996. In addition, we constrain ℓ to be 1 or 2 for the main pulsations in the normal multiperiodic state. The spectra are best fit for Teff}=24 100± 400 K, log g=7.91±0.26 and d=42.7±2.5 pc. The ultraviolet spectroscopic distance is in better agreement with the seismological value, than the one derived by parallax.

  18. Pulsating proton aurora caused by rising tone Pc1 waves

    NASA Astrophysics Data System (ADS)

    Nomura, R.; Shiokawa, K.; Omura, Y.; Ebihara, Y.; Miyoshi, Y.; Sakaguchi, K.; Otsuka, Y.; Connors, M.

    2016-02-01

    We found rising tone emissions with a dispersion of ˜1 Hz per several tens of seconds in the dynamic spectrum of a Pc1 geomagnetic pulsation (Pc1) observed on the ground. These Pc1 rising tones were successively observed over ˜30 min from 0250 UT on 14 October 2006 by an induction magnetometer at Athabasca, Canada (54.7°N, 246.7°E, magnetic latitude 61.7°N). Simultaneously, a Time History of Events and Macroscale Interactions during Substorms panchromatic (THEMIS) all-sky camera detected pulsations of an isolated proton aurora with a period of several tens of seconds, ˜10% variations in intensity, and fine structures of 3° in magnetic longitudes. The pulsations of the proton aurora close to the zenith of ATH have one-to-one correspondences with the Pc1 rising tones. This suggests that these rising tones scatter magnetospheric protons intermittently at the equatorial region. The radial motion of the magnetospheric source, of which the isolated proton aurora is a projection, can explain the central frequency increase of Pc1, but not the shorter period (tens of seconds) frequency increase of ˜1 Hz in Pc1 rising tones. We suggest that EMIC-triggered emissions generate the frequency increase of Pc1 rising tones on the ground and that they also cause the Pc1 pearl structure, which has a similar characteristic time.

  19. Are dayside long-period pulsations related to the cusp?

    NASA Astrophysics Data System (ADS)

    Pilipenko, V.; Belakhovsky, V.; Engebretson, M. J.; Kozlovsky, A.; Yeoman, T.

    2015-03-01

    We compare simultaneous observations of long-period ultra-low-frequency (ULF) wave activity from a Svalbard/IMAGE fluxgate magnetometer latitudinal profile covering the expected cusp geomagnetic latitudes. Irregular Pulsations at Cusp Latitudes (IPCL) and narrowband Pc5 waves are found to be a ubiquitous element of ULF activity in the dayside high-latitude region. To identify the ionospheric projections of the cusp, we use the width of return signal of the Super Dual Auroral Radar Network (SuperDARN) radar covering the Svalbard archipelago, predictions of empirical cusp models, augmented whenever possible by Defense Meteorological Satellite Program (DMSP) identification of magnetospheric boundary domains. The meridional spatial structure of broadband dayside Pc5-6 pulsation spectral power has been found to have a localized latitudinal peak, not under the cusp proper as was previously thought, but several degrees southward from the equatorward cusp boundary. The earlier claims of the dayside monochromatic Pc5 wave association with the open-closed boundary also seems doubtful. Transient currents producing broadband Pc5-6 probably originate at the low-latitude boundary layer/central plasma sheet (LLBL/CPS) interface, though such identification with available DMSP data is not very precise. The occurrence of broadband Pc5-6 pulsations in the dayside boundary layers is a challenge to modelers because so far their mechanism has not been firmly identified.

  20. Temporal characteristics and energy deposition of pulsating auroral patches

    NASA Astrophysics Data System (ADS)

    Humberset, B. K.; Gjerloev, J. W.; Samara, M.; Michell, R. G.; Mann, I. R.

    2016-07-01

    We present a careful statistical analysis of pulsating aurora (PA) using all-sky green line (557.7 nm) images obtained at 3.3 Hz. Six well-defined individual PA patches are identified and extracted using a contouring technique. Quantitative parameters such as the patch duration (on-time and off-time), peak intensity, and integrated intensity are determined for each patch and each pulsation. The resulting characteristics serve as strict observational constraints that any of the many competing theories attempting to explain PA must predict. The purpose of this paper is to determine the characteristics of PA patches in order to provide better observational constraints on the suggested mechanisms. All aspects of the temporal behavior of the individual patches appear to be erratic. Historically, PA has been defined very loosely and we argue that the use of the term "pulsating" is inappropriate since our findings and other published results are not regularly periodic and thus a more appropriate term may be fluctuating aurora. Further, we find that the observational constraints do not fit well with the flow cyclotron maser theory, which in particular is suggested to create PA patches. There is no clear candidate of the suggested mechanisms and drivers to explain the observational constraints set by the PA patches in a satisfactory manner.

  1. Dark Stars: Improved Models and First Pulsation Results

    NASA Astrophysics Data System (ADS)

    Rindler-Daller, T.; Montgomery, M. H.; Freese, K.; Winget, D. E.; Paxton, B.

    2015-02-01

    We use the stellar evolution code MESA to study dark stars (DSs). DSs, which are powered by dark matter (DM) self-annihilation rather than by nuclear fusion, may be the first stars to form in the universe. We compute stellar models for accreting DSs with masses up to 106 M ⊙. The heating due to DM annihilation is self-consistently included, assuming extended adiabatic contraction of DM within the minihalos in which DSs form. We find remarkably good overall agreement with previous models, which assumed polytropic interiors. There are some differences in the details, with positive implications for observability. We found that, in the mass range of 104-105 M ⊙, our DSs are hotter by a factor of 1.5 than those in Freese et al., are smaller in radius by a factor of 0.6, denser by a factor of three to four, and more luminous by a factor of two. Our models also confirm previous results, according to which supermassive DSs are very well approximated by (n = 3)-polytropes. We also perform a first study of DS pulsations. Our DS models have pulsation modes with timescales ranging from less than a day to more than two years in their rest frames, at z ~ 15, depending on DM particle mass and overtone number. Such pulsations may someday be used to identify bright, cool objects uniquely as DSs; if properly calibrated, they might, in principle, also supply novel standard candles for cosmological studies.

  2. Russian Pulsating Mixer Pump. Innovative Technology Summary Report

    SciTech Connect

    2002-03-01

    This sludge mixing/mobilization system was developed in Russia. A prototype system was evaluated by the Tanks Focus Area (TFA) and Industry and University Programs (INDP). The Russian Pulsating Mixer Pump showed promise for mixing highly viscous sludges. This project is to refine the system design (especially the control subsystem) and manufacture the system in Russia in accordance with quality standards required for deployment in radioactive waste storage tanks. Specifications and requirements are being developed by the TFA and INDP. The requirements may call for two or three of the sludge mixing systems to be delivered to Oak Ridge. DOE-Oak Ridge and the Oak Ridge National Laboratory will deploy the pulsating mixing pump system in their Gunite Tanks. These tanks are being emptied and cleaned prior to closure. Oak Ridge has deployed a number of innovative technologies in these efforts. If successful at Oak Ridge, the pulsating mixing pump system has potential application at several other DOE sites, including Savannah River, Hanford, and Idaho.

  3. Mass-spring model of a self-pulsating drop.

    PubMed

    Antoine, Charles; Pimienta, Véronique

    2013-12-01

    Self-pulsating sessile drops are a striking example of the richness of far-from-equilibrium liquid/liquid systems. The complex dynamics of such systems is still not fully understood, and simple models are required to grasp the mechanisms at stake. In this article, we present a simple mass-spring mechanical model of the highly regular drop pulsations observed in Pimienta, V.; Brost, M.; Kovalchuk, N.; Bresch, S.; Steinbock, O. Complex shapes and dynamics of dissolving drops of dichloromethane. Angew. Chem., Int. Ed. 2011, 50, 10728-10731. We introduce an effective time-dependent spreading coefficient that sums up all of the forces (due to evaporation, solubilization, surfactant transfer, coffee ring effect, solutal and thermal Marangoni flows, drop elasticity, etc.) that pull or push the edge of a dichloromethane liquid lens, and we show how to account for the periodic rim breakup. The model is examined and compared against experimental observations. The spreading parts of the pulsations are very rapid and cannot be explained by a constant positive spreading coefficient or superspreading.

  4. THE PULSATION MODE AND DISTANCE OF THE CEPHEID FF AQUILAE

    SciTech Connect

    Turner, D. G.; Kovtyukh, V. V.; Luck, R. E.; Berdnikov, L. N. E-mail: val@deneb1.odessa.ua E-mail: leonid.berdnikov@gmail.com

    2013-07-20

    The determination of pulsation mode and distance for field Cepheids is a complicated problem best resolved by a luminosity estimate. For illustration a technique based on spectroscopic luminosity discrimination is applied to the 4.47 day s-Cepheid FF Aql. Line ratios in high dispersion spectra of the variable yield values of (M{sub V} ) = -3.40 {+-} 0.02 s.e. ({+-}0.04 s.d.), average effective temperature T{sub eff} = 6195 {+-} 24 K, and intrinsic color ((B) - (V)){sub 0} = +0.506 {+-} 0.007, corresponding to a reddening of E{sub B-V} = 0.25 {+-} 0.01, or E{sub B-V}(B0) = 0.26 {+-} 0.01. The skewed light curve, intrinsic color, and luminosity of FF Aql are consistent with fundamental mode pulsation for a small-amplitude classical Cepheid on the blue side of the instability strip, not a sinusoidal pulsator. A distance of 413 {+-} 14 pc is estimated from the Cepheid's angular diameter in conjunction with a mean radius of (R) = 39.0 {+-} 0.7 R{sub Sun} inferred from its luminosity and effective temperature. The dust extinction toward FF Aql is described by a ratio of total-to-selective extinction of R{sub V} = A{sub V} /E(B - V) = 3.16 {+-} 0.34 according to the star's apparent distance modulus.

  5. An Observational Study of Pulsations in Proto-Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Hrivnak, Bruce J.; Lu, Wenxian; Henson, Gary D.; Hillwig, Todd C.

    2016-01-01

    We have been carrying out a long-term monitoring program to study the light variability in proto-planetary nebulae (PPNe). PPNe are post-Asymptotic Giant Branch objects in transition between the AGB and PN phases in the evolution of low and intermediate-mass stars. As such, it is not surprising that they display pulsational variability. We have been carrying out photometric monitoring of 30 of these at the Valparaiso University campus observatory over the last 20 years, with the assistance of undergraduate students. The sample size has been enlarged over the past six years by observations made using telescopes in the SARA consortium at KPNO and CTIO. Periods have been determined for those of F-G spectral types. We have also enlarged the sample with PPNe from outside the Milky Way by determining periods of eight PPNe in the lower metalicity environment of the Magellanic Clouds. Periods for the entire sample range from 35 to 160 days. Some clear patterns have emerged, with those of higher temperature possessing shorter periods and smaller amplitudes, indicating a reduction in period and pulsation amplitude as the objects evolve. Radial velocity monitoring of several of the brightest of these has allowed us to document their changes in brightness, color, and size during a pulsation cycle. The results of this study will be presented. This research is supported by grants from the National Science Foundation (most recently AST 1413660), with additional student support from the Indiana Space Grant Consortium.

  6. Stellar Pulsations Excited by Planetary Tides in WASP-33

    NASA Astrophysics Data System (ADS)

    Cameron, Andrew; Guenther, E.; Matthews, J. M.; Amado, P. J.; McDonald, I.; Shkolnik, E.; Smith, A. M. S.; Telting, J.; Walker, G. A. H.; MOST Science Team

    2011-09-01

    The bright, rapidly-rotating A5 star HD 15082 (= WASP-33) has a transiting gas-giant planet in a 1.22-day retrograde orbit, only 5.5 stellar radii from the stellar photosphere (Collier Cameron et al 2010, MNRAS 407, 507). Time-resolved spectra of the system during several transits revealed a complex pattern of non-radial pulsations of the gamma Dor and/or delta Scuti type. The extreme proximity of the planet to the host star raises the possibility that some of these pulsation modes could be excited by planetary tides (Herrero et al 2011 A&A 526, L10). The system was observed continuously by the MOST satellite(*) from 2010 October 07.0 to October 31.0. The MOST data establish the frequency spectrum of the stellar pulsations, providing a direct test of theories of planetary tidal evolution via excitation of inertial waves in the host star. The ellipsoidal variation of the host star places limits on the mass of the planet. During the MOST run, a ground-based support campaign of time-resolved echelle spectroscopy yielded tomographic data sets suitable for mode identification and precise determination of the orientation of the planet's orbit. (*) MOST is a Canadian Space Agency mission, operated by Microsat Systems Canada Inc. (formerly the space division of Dynacon Inc.), the University of Toronto Institute for Aerospace Studies and the University of British Columbia, with support from the University of Vienna.

  7. Mass-spring model of a self-pulsating drop.

    PubMed

    Antoine, Charles; Pimienta, Véronique

    2013-12-01

    Self-pulsating sessile drops are a striking example of the richness of far-from-equilibrium liquid/liquid systems. The complex dynamics of such systems is still not fully understood, and simple models are required to grasp the mechanisms at stake. In this article, we present a simple mass-spring mechanical model of the highly regular drop pulsations observed in Pimienta, V.; Brost, M.; Kovalchuk, N.; Bresch, S.; Steinbock, O. Complex shapes and dynamics of dissolving drops of dichloromethane. Angew. Chem., Int. Ed. 2011, 50, 10728-10731. We introduce an effective time-dependent spreading coefficient that sums up all of the forces (due to evaporation, solubilization, surfactant transfer, coffee ring effect, solutal and thermal Marangoni flows, drop elasticity, etc.) that pull or push the edge of a dichloromethane liquid lens, and we show how to account for the periodic rim breakup. The model is examined and compared against experimental observations. The spreading parts of the pulsations are very rapid and cannot be explained by a constant positive spreading coefficient or superspreading. PMID:24200165

  8. Drill pipe protector development

    SciTech Connect

    Thomerson, C.; Kenne, R.; Wemple, R.P.

    1996-03-01

    The Geothermal Drilling Organization (GDO), formed in the early 1980s by the geothermal industry and the U.S. Department of Energy (DOE) Geothermal Division, sponsors specific development projects to advance the technologies used in geothermal exploration, drilling, and production phases. Individual GDO member companies can choose to participate in specific projects that are most beneficial to their industry segment. Sandia National Laboratories is the technical interface and contracting office for the DOE in these projects. Typical projects sponsored in the past have included a high temperature borehole televiewer, drill bits, muds/polymers, rotary head seals, and this project for drill pipe protectors. This report documents the development work of Regal International for high temperature geothermal pipe protectors.

  9. 9 CFR 3.114 - Primary conveyances (motor vehicle, rail, air and marine).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... conveyances (motor vehicle, rail, air and marine). (a) The animal cargo space of primary conveyances used in... safety and comfort of the marine mammals contained within at all times. All primary conveyances used must... animal cargo space must be constructed and maintained in a manner that will prevent the ingress of...

  10. Investigations on the Aerodynamic Characteristics and Blade Excitations of the Radial Turbine with Pulsating Inlet Flow

    NASA Astrophysics Data System (ADS)

    Liu, Yixiong; Yang, Ce; Yang, Dengfeng; Zhang, Rui

    2016-04-01

    The aerodynamic performance, detailed unsteady flow and time-based excitations acting on blade surfaces of a radial flow turbine have been investigated with pulsation flow condition. The results show that the turbine instantaneous performance under pulsation flow condition deviates from the quasi-steady value significantly and forms obvious hysteretic loops around the quasi-steady conditions. The detailed analysis of unsteady flow shows that the characteristic of pulsation flow field in radial turbine is highly influenced by the pulsation inlet condition. The blade torque, power and loading fluctuate with the inlet pulsation wave in a pulse period. For the blade excitations, the maximum and the minimum blade excitations conform to the wave crest and wave trough of the inlet pulsation, respectively, in time-based scale. And toward blade chord direction, the maximum loading distributes along the blade leading edge until 20% chord position and decreases from the leading to trailing edge.

  11. Heat Pipe Systems

    NASA Astrophysics Data System (ADS)

    1988-01-01

    Solar Fundamentals, Inc.'s hot water system employs space-derived heat pipe technology. It is used by a meat packing plant to heat water for cleaning processing machinery. Unit is complete system with water heater, hot water storage, electrical controls and auxiliary components. Other than fans and a circulating pump, there are no moving parts. System's unique design eliminates problems of balancing, leaking, corroding, and freezing.

  12. Underground pipeline laying using the pipe-in-pipe system

    NASA Astrophysics Data System (ADS)

    Antropova, N.; Krets, V.; Pavlov, M.

    2016-09-01

    The problems of resource saving and environmental safety during the installation and operation of the underwater crossings are always relevant. The paper describes the existing methods of trenchless pipeline technology, the structure of multi-channel pipelines, the types of supporting and guiding systems. The rational design is suggested for the pipe-in-pipe system. The finite element model is presented for the most dangerous sections of the inner pipes, the optimum distance is detected between the roller supports.

  13. Pipe inspection using the pipe crawler. Innovative technology summary report

    SciTech Connect

    1999-05-01

    The US Department of Energy (DOE) continually seeks safer and more cost-effective remediation technologies for use in the decontamination and decommissioning (D and D) of nuclear facilities. In several of the buildings at the Fernald Site, there is piping that was used to transport process materials. As the demolition of these buildings occur, disposal of this piping has become a costly issue. Currently, all process piping is cut into ten-foot or less sections, the ends of the piping are wrapped and taped to prevent the release of any potential contaminants into the air, and the piping is placed in roll off boxes for eventual repackaging and shipment to the Nevada Test Site (NTS) for disposal. Alternatives that allow for the onsite disposal of process piping are greatly desired due to the potential for dramatic savings in current offsite disposal costs. No means is currently employed to allow for the adequate inspection of the interior of piping, and consequently, process piping has been assumed to be internally contaminated and thus routinely disposed of at NTS. The BTX-II system incorporates a high-resolution micro color camera with lightheads, cabling, a monitor, and a video recorder. The complete probe is capable of inspecting pipes with an internal diameter (ID) as small as 1.4 inches. By using readily interchangeable lightheads, the same system is capable of inspecting piping up to 24 inches in ID. The original development of the BTX system was for inspection of boiler tubes and small diameter pipes for build-up, pitting, and corrosion. However, the system is well suited for inspecting the interior of most types of piping and other small, confined areas. The report describes the technology, its performance, uses, cost, regulatory and policy issues, and lessons learned.

  14. Guidable pipe plug

    DOEpatents

    Glassell, Richard L.; Babcock, Scott M.; Lewis, Benjamin E.

    2001-01-01

    A plugging device for closing an opening defined by an end of a pipe with sealant comprises a cap, an extension, an inner seal, a guide, and at least one stop. The cap has an inner surface which defines a chamber adapted for retaining the sealant. The chamber is dimensioned slightly larger than the end so as to receive the end. The chamber and end define a gap therebetween. The extension has a distal end and is attached to the inner surface opposite the distal end. The inner seal is attached to the extension and sized larger than the opening. The guide is positioned forward of the inner seal and attached to the distal end. The guide is also dimensioned to be inserted into the opening. The stop is attached to the extender, and when the stop is disposed in the pipe, the stop is movable with respect to the conduit in one direction and also prevents misalignment of the cap with the pipe. A handle can also be included to allow the cap to be positioned robotically.

  15. Pipe damping studies

    SciTech Connect

    Ware, A.G.

    1986-01-01

    The Idaho National Engineering Laboratory (INEL) is conducting a research program to assist the United States Nuclear Regulatory Commission (USNRC) in determining best-estimate damping values for use in the dynamic analysis of nuclear power plant piping systems. This paper describes four tasks in the program that were undertaken in FY-86. In the first task, tests were conducted on a 5-in. INEL laboratory piping system and data were analyzed from a 6-in. laboratory system at the ANCO Engineers facility to investigate the parameters influencing damping in the seismic frequency range. Further tests were conducted on 3- and 5-in. INEL laboratory piping systems as the second task to determine damping values representative of vibrations in the 33 to 100 Hz range, typical of hydrodynamic transients. In the third task a statistical evaluation of the available damping data was conduted to determine probability distributions suitable for use in probabilistic risk assessments (PRAs), and the final task evaluated damping data at high strain levels.

  16. Evaluation of the Serpentix Conveying System. Final technical report

    SciTech Connect

    Not Available

    1980-03-01

    The Serpentix Conveying System, a Peabody Coal Company underground continuous face haulage invention, was evaluated to determine its viability in room-and-pillar mining. The Serpentix is a mobile, flexible belt conveyor which is suspended from the mine roof. It was operated in the Illinois No. 6 Mine No. 1 at Marissa, Illinois and Mine No. 10 at pawnee, Illinois. Production rates in excess of 1100 raw tons per eight-hour shift were demonstrated. Conceptual designs were developed to suspend the Serpentix system from chocks for shortwall mining applications.

  17. Product suitable for the storage and conveyance of thermal energy

    SciTech Connect

    Babin, L.; Clausse, D.

    1981-09-01

    This invention concerns the storage and conveyance of thermal energy at low temperature, by using the latent heat produced by a substance during changes of state. This substance consists of a salt producing considerable latent heat during change of state, such as NA/sub 2/SO/sub 4/, 10 H/sub 2/O, combined closely with a nucleating agent such as borax and dispersed in an oil to which an emulsifying agent has been added. This product is particularly suitable for storage of solar energy at low temperature and for heating of enclosed areas.

  18. Heat pipe technology: A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The annual supplement on heat pipe technology for 1971 is presented. The document contains 101 references with abstracts and 47 patents. The subjects discussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design, development, and fabrication of heat pipes, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  19. Substructures with luminosity modulation and horizontal oscillation in pulsating patch: Principal component analysis application to pulsating aurora

    NASA Astrophysics Data System (ADS)

    Nishiyama, Takanori; Miyoshi, Yoshizumi; Katoh, Yuto; Sakanoi, Takeshi; Kataoka, Ryuho; Okano, Shoichi

    2016-03-01

    We observed a mesoscale aurora (100 km × 100 km) with patchy structure and equatorward propagation at Poker Flat Research Range on 1 December 2011. Fast Fourier transform (FFT) analysis revealed that this pulsating patch clearly exhibited temporal variations that can be categorized into two types: on-off pulsation (7.8-10 s) with large amplitudes and luminosity modulations excited during on phase with a frequency of about 3.0 Hz. In addition, we applied principal component analysis (PCA) to time series image data of the pulsating aurora for the first time. Time coefficients were estimated by PCA for the whole patch and the substructures were consistent with those obtained from the FFT analysis, and therefore, we concluded that PCA is capable of decomposing several structures that have different coherent spatiotemporal characteristics. Another new insight in this study is that the rapid variations were highly localized; they were excited in only the substructures embedded in the whole structure. Moreover, the whole patch propagated equatorward because of E × B drift of cold plasma, while the substructures did not show such systematic propagation but rather forward-backward oscillations. The horizontal scale of the substructures was estimated to be no smaller than 410 km at the magnetic equator, which is comparable to that of the wave packet structure of a whistler mode chorus perpendicular to the field line. We suggest that the apparent horizontal oscillation of the substructures is associated with field-aligned propagations of the whistler mode chorus in a duct.

  20. Experimenting with a ``Pipe'' Whistle

    NASA Astrophysics Data System (ADS)

    Stafford, Olga

    2012-04-01

    A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here allows students in a physics of music or introductory physics course to study an example of an "edge tone" device that produces discrete sound frequencies. From their textbooks, students likely know about standing waves produced by pipes or strings, as well as the resonant frequencies for open and closed pipes. To go a bit further, they can also learn how the frequency of the sound wave depends on the orifice-to-edge distance of the wind instrument.

  1. Energies of precipitating electrons during pulsating aurora events derived from ionosonde observations

    NASA Astrophysics Data System (ADS)

    MacDougall, J. W.; Hofstee, J.; Koehler, J. A.

    1981-08-01

    The time-history of particle energies and fluxes associated with pulsating auroras in the morning sector is derived using ionosonde measurements. All the pulsating auroras studied show a similar history with the pulsations occurring during a time interval of the order of an hour during which the average auroral Maxwellian characteristic energy stays relatively constant but the energy flux decreases progressively during the event. A possible explanation for this behavior is suggested in terms of an injection of particles into a magnetospheric 'bottle' near the midnight meridian and the progressive precipitation out of the bottle during the pulsating event.

  2. White Dwarf Period Tables I. Pulsators with hydrogen-dominated atmospheres

    NASA Astrophysics Data System (ADS)

    Bognar, Zs.; Sodor, A.

    2016-09-01

    We aimed at collecting all known white dwarf pulsators with hydrogen-dominated atmospheres and list their main photometric and atmospheric parameters together with their pulsation periods and amplitudes observed at different epochs. For this purpose, we explored the pulsating white dwarf related literature with the systematic use of the SIMBAD and the NASA's Astrophysics Data System (ADS) databases. We summarized our results in four tables listing seven ZZ Ceti stars in detached white dwarf plus main-sequence binaries, seven extremely low-mass DA pulsators, three hot DAVs and 180 ZZ Ceti stars.

  3. Observations of candidate oscillating eclipsing binaries and two newly discovered pulsating variables

    NASA Astrophysics Data System (ADS)

    Liakos, A.; Niarchos, P.

    2009-03-01

    CCD observations of 24 eclipsing binary systems with spectral types ranging between A0-F0, candidate for containing pulsating components, were obtained. Appropriate exposure times in one or more photometric filters were used so that short-periodic pulsations could be detected. Their light curves were analyzed using the Period04 software in order to search for pulsational behaviour. Two new variable stars, namely GSC 2673-1583 and GSC 3641-0359, were discov- ered as by-product during the observations of eclipsing variables. The Fourier analysis of the observations of each star, the dominant pulsation frequencies and the derived frequency spectra are also presented.

  4. First Satellite Imaging of Auroral Pulsations by the Fast Auroral Imager on e-POP

    NASA Astrophysics Data System (ADS)

    Lui, A.; Cogger, L.; Howarth, A. D.; Yau, A. W.

    2015-12-01

    We report the first satellite imaging of auroral pulsations by the Fast Auroral Imager (FAI) onboard the Enhanced Polar Outflow Probe (e-POP) satellite. The near-infrared camera of FAI is capable of providing up to two auroral images per second, ideal for investigation of pulsating auroras. The auroral pulsations were observed within the auroral bulge formed during a substorm interval on 2014 February 19. This first satellite view of these pulsations from FAI reveals that (1) several pulsating auroral channels (PACs) occur within the auroral bulge, (2) periods of the intensity pulsations span over one decade within the auroral bulge, and (3) there is no apparent trend of longer pulsation periods associated with higher latitudes for these PACs. Although PACs resemble in some respect stable pulsating auroras reported previously but they have several important differences in characteristics.PACs are not embedded in or emerging from omega bands or torches and are located at significant distances from the equatorward boundary of the auroral oval, unlike the characteristics of stable pulsating auroras.

  5. Cepheids in Magellanic Cloud star clusters - Fundamental and overtone pulsators in NGC 2157

    NASA Technical Reports Server (NTRS)

    Mateo, Mario; Olszewski, Edward W.; Madore, Barry F.

    1990-01-01

    CCD survey data are employed to examine Cepheids in young Magellanic Cloud star clusters. The properties of three Cepheids observed in NGC 2157 are described. It is detected that the two short-period (3 days) Cepheids have photometric properties that correspond to overtone pulsators and the long-period (7.7 days) Cepheid pulses in the fundamental mode. The pulsational masses for the three Cepheids are calculated to be about 5 solar masses. This mass value does not correlate with the average pulsational mass for Cepheids of 3.0 + or - 0.4 solar masses. The potential cause of this deviation in evolutionary/pulsational mass is investigated.

  6. Insulating Cryogenic Pipes With Frost

    NASA Technical Reports Server (NTRS)

    Stephenson, J. G.; Bova, J. A.

    1985-01-01

    Crystallized water vapor fills voids in pipe insulation. Small, carefully controlled amount of water vapor introduced into dry nitrogen gas before it enters aft fuselage. Vapor freezes on pipes, filling cracks in insulation. Ice prevents gaseous nitrogen from condensing on pipes and dripping on structure, in addition to helping to insulate all parts. Industrial applications include large refrigeration plants or facilities that use cryogenic liquids.

  7. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Astrophysics Data System (ADS)

    McIntosh, Roy

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  8. Thermostructural applications of heat pipes

    NASA Technical Reports Server (NTRS)

    Peeples, M. E.; Reeder, J. C.; Sontag, K. E.

    1979-01-01

    The feasibility of integrating heat pipes in high temperature structure to reduce local hot spot temperature was evaluated for a variety of hypersonic aerospace vehicles. From an initial list of twenty-two potential applications, the single stage to orbit wing leading edge showed the greatest promise and was selected for preliminary design of an integrated heat pipe thermostructural system. The design consisted of a Hastelloy X assembly with sodium heat pipe passages aligned normal to the wing leading edge. A d-shaped heat pipe cross section was determined to be optimum from the standpoint of structural weight.

  9. Cryogenic Heat Pipe Experiment (CRYOHP)

    NASA Technical Reports Server (NTRS)

    Mcintosh, Roy

    1992-01-01

    The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

  10. Perceived facial adiposity conveys information about women's health.

    PubMed

    Tinlin, Rowan M; Watkins, Christopher D; Welling, Lisa L M; DeBruine, Lisa M; Al-Dujaili, Emad A S; Jones, Benedict C

    2013-05-01

    Although several prominent theories of human facial attractiveness propose that some facial characteristics convey information about people's health, empirical evidence for this claim is somewhat mixed. While most previous research into this issue has focused on facial characteristics such as symmetry, averageness, and sexual dimorphism, a recent study reported that ratings of facial adiposity (i.e., perceptions of fatness in the face) were positively correlated with indices of poor physical condition in a sample of young adults (i.e., reported past health problems and measures of cardiovascular fitness). These findings are noteworthy, since they suggest that perceived adiposity is a potentially important facial cue of health that has been overlooked by much of the previous work in this area. Here, we show that ratings of young adult women's facial adiposity are (1) better predicted by their body weight than by their body shape (Studies 1 and 2), (2) correlated with a composite measure of their physical and psychological condition (Study 2), and (3) negatively correlated with their trait (i.e., average) salivary progesterone levels (Study 3). Together, these findings present further evidence that perceived facial adiposity, or a correlate thereof, conveys potentially important information about women's actual health. PMID:23560669

  11. 32 CFR 644.560 - Inspections of civilian component training facilities and other properties conveyed subject to...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... economy. This requirement for inspections extends to properties conveyed by the Secretary of the Army or... National Security Clause, and similar conditions, in deeds conveying industrial properties....

  12. 32 CFR 644.560 - Inspections of civilian component training facilities and other properties conveyed subject to...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... economy. This requirement for inspections extends to properties conveyed by the Secretary of the Army or... National Security Clause, and similar conditions, in deeds conveying industrial properties....

  13. Deployable Pipe-Z

    NASA Astrophysics Data System (ADS)

    Zawidzki, Machi

    2016-10-01

    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the "dead link". A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  14. Large-bore pipe decontamination

    SciTech Connect

    Ebadian, M.A.

    1998-01-01

    The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system.

  15. Ceramic heat pipe wick

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

    1989-01-01

    A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

  16. Removal of Pipe Fouling Inside Pipes Using Ultrasonic Waves

    NASA Astrophysics Data System (ADS)

    Nakagawa, Noritoshi; Fujihara, Masaya; Wu, Chaoqun; Satonobu, Jun

    Since fouling generated inside pipes of chemistry plant equipment, shortens “its life”, periodical maintenance such as cleaning or replacement is needed. Therefore, the development of a safe and sanitary method of preventing a corrosion and blockage inside pipes is desired. In this study, a vibration system, composed of a bolt-clamped Langevin transducer and a pipe, was employed to experimentally study the possibility of fouling removal. In the experiment, a flexural vibration was excited in a pipe containing fouling using ultrasonic waves. When the pipe was made to vibrate, with calcium carbonate or starch used as the fouling, it was shown that the fouling was diffused into the air, and except at the node of the flexural vibration, the fouling was removed completely. Also, the result showed that a higher input voltage to the transducer was more effective in removing the fouling.

  17. The Domains of Instability for the Pulsating PG 1159 Stars

    NASA Astrophysics Data System (ADS)

    Quirion, P.-O.; Fontaine, G.; Brassard, P.; Herwig, F.

    2005-07-01

    The fact that we find pulsating and nonpulsating stars mixed together in the PG 1159 region of the log g-Teff diagram has been a long standing puzzle. The poor understanding of the driving mechanism in those stars has been the reason why it has taken so long to address properly this problem. Following the work of Saio (1996) and Gautchy (1997) based on the OPAL opacities, Quirion et al. (2004) recently showed that we are now able to understand and reproduce the ranges of observed periods in the pulsating PG 1159 stars in terms of the original κ-mechanism associated with the partial ionization of the K-shell electrons of C and O which, along with He, make up the composition of the envelope of those stars. Contrary to others, those three studies agree in that no composition gradients are needed between the atmospheric layers and the driving region. Furthermore, the cohabitation of pulsating and nonpulsating PG 1159 stars is naturally explained in terms of a dispersion in atmospheric parameters and in terms of a variation in surface composition from star to star. In particular, the most He-rich stars tend to be stable. We go beyond the findings discussed by Quirion et al. (2004) in this paper, and present the results of additional calculations aimed at describing better the role of the chemical composition (in particular the role of metallicity) as well as that of the stellar mass on the boundaries of the instability domain in the log g-Teff plane.

  18. 9 Aurigae: strong evidence for non-radial pulsations

    NASA Astrophysics Data System (ADS)

    Krisciunas, K.; Griffin, R. F.; Guinan, E. F.; Luedeke, K. D.; McCook, G. P.

    1995-04-01

    We present further photometric observations of the unusual F0 V star 9 Aurigae and present evidence that this star's radial velocity, spectroscopic line widths and line depths are also variable with the same frequencies as the photometric data (f_1~=0.795 and f_2~=0.345 d^-1). The phases of these sinusoids are stable over time-scales of longer than one year, though the amplitudes can vary, making the prediction of photometric behaviour impossible. Given that a variety of other explanations have already been discounted (e.g. interactions with a close companion, the existence of a lumpy, orbiting ring of dust, or star spots) and that these variations occur on time-scales an order of magnitude slower than the fundamental radial pulsation period, we have very strong evidence that 9 Aurigae exhibits non-radial g-mode pulsations. Since the power spectrum of the radial velocity data shows frequency f_2 but does not clearly show f_1, the present data suggest that f_2 is associated with a low-degree spherical harmonic L=1 or 2), while f_1 is associated with a higher degree harmonic. 9 Aurigae, along with such stars as gamma Doradus, HD 224638, HD 224945, and HD 164615, appears to constitute a new class of pulsating variables. These stars are to be found at or beyond the cool edge of the Cepheid instability strip in the HR Diagram. Prior to this, only much hotter stars have been shown to exhibit non-radial g-modes.

  19. The domains of instability for the pulsating PG1159 stars.

    SciTech Connect

    Quirion, P.-O.; Fontaine, Gilles.; Brassard, Pierre; Herwig, F. H.

    2004-01-01

    The fact that we find pulsating and nonpulsating stars mixed together in the PG 1159 region of the log g - T{sub eff} diagram has been a long standing puzzle. The poor understanding of the driving mechanism in those stars has been the reason why it has taken so long to address properly this problem. Following the work of Saio (1996) and Gautschy (1997) based on the OPAL opacities, Quirion, Fontaine, & Brassard (2004) recently showed that we are now able to understand and reproduce the ranges of observed periods in the pulsating PG 1159 stars in terms of the original {kappa}-mechanism associated with the partial ionization of the K-shell electrons of C and O which, along with He, make up the composition of the envelope of those stars. Contrary to others, those three studies agree in that no composition gradients are needed between the atmospheric layers and the driving region. Furthermore, the cohabitation of pulsating and nonpulsating PG 1159 stars is naturally explained in terms of a dispersion in atmospheric parameters and in terms of a variation in surface composition from star to star. In particular, the most He-rich stars tend to be stable. We go beyond the findings discussed by Quirion et al. (2004) in this paper, and present the results of additional calculations aimed at describing better the role of the chemical composition (in particular the role of metallicity) as well as that of the stellar mass on the boundaries of the instability domain in the log g - T{sub eff} plane.

  20. Alternate high capacity heat pipe

    NASA Technical Reports Server (NTRS)

    Voss, F. E.

    1986-01-01

    The performance predictions for a fifty foot heat pipe (4 foot evaporator - 46 foot condensor) are discussed. These performance predictions are supported by experimental data for a four foot heat pipe. Both heat pipes have evaporators with axial groove wick structures and condensers with powder metal external artery wick structures. The predicted performance of a rectangular axial groove/external artery heat pipe operating in space is given. Heat transport versus groove width is plotted for 100, 200 and 300 grooves in the evaporator. The curves show that maximum power is achieved for groove widths from 0.040 to 0.053 as the number of grooves varies from 300 to 100. The corresponding range of maximum power is 3150 to 2400 watts. The relationships between groove width and heat pipe evaporate diameter for 100, 200 and 300 grooves in the evaporator are given. A four foot heat pipe having a three foot condenser and one foot evaporator was built and tested. The evaporator wick structure used axial grooves with rectangular cross sections, and the condenser wick structure used powder metal with an external artery configuration. Fabrication drawings are enclosed. The predicted and measured performance for this heat pipe is shown. The agreement between predicted and measured performance is good and therefore substantiates the predicted performance for a fifty foot heat pipe.

  1. Building a Copper Pipe "Xylophone."

    ERIC Educational Resources Information Center

    Lapp, David R.

    2003-01-01

    Explains how to use the equation for frequency of vibration of a transversely oscillating bar or pipe with both ends free to vibrate to build a simple and inexpensive xylophone from a 3-meter section of copper pipe. The instrument produces a full major scale and can be used to investigate various musical intervals. (Author/NB)

  2. Demonstrating Sound Impulses in Pipes.

    ERIC Educational Resources Information Center

    Raymer, M. G.; Micklavzina, Stan

    1995-01-01

    Describes a simple, direct method to demonstrate the effects of the boundary conditions on sound impulse reflections in pipes. A graphical display of the results can be made using a pipe, cork, small hammer, microphone, and fast recording electronics. Explains the principles involved. (LZ)

  3. Heat Pipe Blocks Return Flow

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1982-01-01

    Metal-foil reed valve in conventional slab-wick heat pipe limits heat flow to one direction only. With sink warmer than source, reed is forced closed and fluid returns to source side through annular transfer wick. When this occurs, wick slab on sink side of valve dries out and heat pipe ceases to conduct heat.

  4. Pipe crawler with stabilizing midsection

    SciTech Connect

    Zollinger, W.T.; Treanor, R.C.

    1993-09-20

    This invention is comprised of a pipe crawler having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ``inch worm`` fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  5. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe crawler having a midsection that provides the stability and flexibty to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in "inch worm" fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting.

  6. Pipe crawler with stabilizing midsection

    DOEpatents

    Zollinger, W.T.; Treanor, R.C.

    1994-12-27

    A pipe crawler is described having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ''inch worm'' fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting. 5 figures.

  7. Electrodynamic response of the middle atmosphere to auroral pulsations

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Barcus, J. R.

    1990-01-01

    The MAC/EPSILON observational campaign encompassed the use of two Nike Orion rocket payloads which studied the effects of auroral energetics on the middle atmosphere. While one payload was launched during the recovery phase of a moderate magnetic substorm, during fairly stable auroral conditions, the other was launched during highly active postbreakup conditions during which Pc5 pulsations were in progress. The energetic radiation of the first event was composed almost entirely of relativistic electrons below 200 keV, while that of the second was dominated by much softer electrons whose high X-ray fluxes exceeded the cosmic ray background as an ionizing source down to below 30 km.

  8. Optical multichannel monitoring of skin blood pulsations for cardiovascular assessment

    NASA Astrophysics Data System (ADS)

    Spigulis, Janis; Erts, Renars; Ozols, Maris

    2004-07-01

    Time resolved detection and analysis of the skin back-scattered optical signals (reflection photoplethysmography or PPG) provide rich information on skin blood volume pulsations and can serve for cardiovascular assessment. The multichannel PPG concept has been developed and clinically verified in this work. Simultaneous data flow from several body locations allows to study the heartbeat pulse wave propagation in real time and to evaluate the vascular resistance. Portable two- and four-channel PPG monitoring devices and special software have been designed for real-time data acquisition and processing. The multi-channel devices were successfully applied for cardiovascular fitness tests and for early detection of arterial occlusions.

  9. Dissipative double-well potential: Nonlinear stationary and pulsating modes

    SciTech Connect

    Zezyulin, Dmitry A.; Konotop, Vladimir V.; Alfimov, Georgy L.

    2010-11-15

    The analysis of nonlinear modes in a complex absorbing double-well potential supported by linear gain is presented. Families of the nonlinear modes and their bifurcations are found numerically by means of the properly modified 'shooting' method. Linear stability and dynamics of the modes are studied. It is shown that no stable modes exist in the case of attractive nonlinearity, while stable modes, including nonsymmetric ones, are found when the nonlinearity is repulsive. Varying a control parameter (e.g., the height of barrier between the wells) results in switching from one mode to another. Apart from stationary modes we have found pulsating solutions emergent from unstable modes.

  10. Pulsations powered by hydrogen shell burning in white dwarfs

    NASA Astrophysics Data System (ADS)

    Camisassa, M. E.; Córsico, A. H.; Althaus, L. G.; Shibahashi, H.

    2016-10-01

    Context. In the absence of a third dredge-up episode during the asymptotic giant-branch phase, white dwarf models evolved from low-metallicity progenitors have a thick hydrogen envelope, which makes hydrogen shell burning be the most important energy source. Aims: We investigate the pulsational stability of white dwarf models with thick envelopes to see whether nonradial g-mode pulsations are triggered by hydrogen burning, with the aim of placing constraints on hydrogen shell burning in cool white dwarfs and on a third dredge-up during the asymptotic giant-branch evolution of their progenitor stars. Methods: We construct white-dwarf sequences from low-metallicity progenitors by means of full evolutionary calculations that take into account the entire history of progenitor stars, including the thermally pulsing and the post-asymptotic giant-branch phases, and analyze their pulsation stability by solving the linear, nonadiabatic, nonradial pulsation equations for the models in the range of effective temperatures Teff 15 000-8000 K. Results: We demonstrate that, for white dwarf models with masses M⋆ ≲ 0.71 M⊙ and effective temperatures 8500 ≲ Teff ≲ 11 600 K that evolved from low-metallicity progenitors (Z = 0.0001, 0.0005, and 0.001), the dipole (ℓ = 1) and quadrupole (ℓ = 2) g1-modes are excited mostly as a result of the hydrogen-burning shell through the ɛ-mechanism, in addition to other g-modes driven by either the κ - γ or the convective driving mechanism. However, the ɛ mechanism is insufficient to drive these modes in white dwarfs evolved from solar-metallicity progenitors. Conclusions: We suggest that efforts should be made to observe the dipole g1-mode in white dwarfs associated with low-metallicity environments, such as globular clusters and/or the galactic halo, to place constraints on hydrogen shell burning in cool white dwarfs and the third dredge-up episode during the preceding asymptotic giant-branch phase.

  11. Correlated pulsations in auroral light intensity and VLF hiss

    NASA Astrophysics Data System (ADS)

    Duthie, D. D.; Rash, J. P. S.; Scourfield, M. W. J.

    1985-12-01

    Observations at Sanae, Antarctica of a pulsating aurora with a low light level TV system have been combined with simultaneous recordings of VLF hiss on a broad band receiver. Both auroral light and hiss intensities display a significant peak at 1.3 Hz in the power spectrum. The peaks in the auroral light intensity variations lead those in the VLF hiss by times between zero and 0.2 s, as revealed by cross-spectral analysis. These results are explained in terms of cyclotron resonance in the equatorial plane between the auroral electrons and echoing VLF hiss.

  12. Stellar Pulsations and Stellar Evolution: Conflict, Cohabitation, or Symbiosis?

    NASA Astrophysics Data System (ADS)

    Weiss, Achim

    While the analysis of stellar pulsations allows the determination of current properties of a star, stellar evolution models connect it with its previous history. In many cases results from both methods do not agree. In this review some classical and current cases of disagreement are presented. In some cases these conflicts led to an improvement of the theory of stellar evolution, while in others they still remain unsolved. Some well-known problems of stellar physics are pointed out as well, for which it is hoped that seismology—or in general the analysis of stellar pulsations—will help to resolve them. The limits of this symbiosis will be discussed as well.

  13. Discovery of a new PG 1159 (GW Vir) pulsator

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.; Fraga, Luciano; Winget, Don Earl; Bell, Keaton; Córsico, Alejandro H.; Werner, Klaus

    2014-08-01

    We report the discovery of pulsations in the spectroscopic PG 1159 type pre-white dwarf SDSS J075415.12 + 085232.18. Analysis of the spectrum by Werner et al. indicated Teff = 120 000 ± 10 000 K, log g = 7.0 ± 0.3, mass {M}=0.52 ± 0.02 M_{⊙}, C/He = 0.33 by number. We obtained time series images with the SOAR 4.1 m telescope and 2.1 m Otto Struve telescope at McDonald Observatory and show the star is also a variable PG 1159 type star, with dominant period of 525 s.

  14. Vapor spill pipe monitor

    NASA Astrophysics Data System (ADS)

    Bianchini, G. M.; McRae, T. G.

    1983-06-01

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote IR gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote IR sensor which measures the gas composition.

  15. Vapor spill pipe monitor

    DOEpatents

    Bianchini, G.M.; McRae, T.G.

    1983-06-23

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

  16. Modular motion control produces cost-effective conveying

    SciTech Connect

    Yackel, R.A.

    1997-08-01

    Collectively, US power plants move as much as 800 million tons of coal a year through the mining, transport, off-loading, stockpiling and consumption sequence, most typically through the use of belt conveyors. Plant operators oversee a process that moves mountains of coal accurately and dependably, guarding against overloading, loss of conveyor-to-conveyor synchronization, belt slippage and other malfunctions. A coal-conveying motion-control system should consist of modular, turnkey motion-sensing components that can be assembled and interconnected for any application without custom engineering. Such a system can be fail-safe, provide uninterrupted protection, resist difficult environmental conditions, integrate complex multiple functions and allow power plant operators to take instant action to protect against damage in the event of a system fault.

  17. Facilitated detection of social cues conveyed by familiar faces.

    PubMed

    Visconti di Oleggio Castello, Matteo; Guntupalli, J Swaroop; Yang, Hua; Gobbini, M Ida

    2014-01-01

    Recognition of the identity of familiar faces in conditions with poor visibility or over large changes in head angle, lighting and partial occlusion is far more accurate than recognition of unfamiliar faces in similar conditions. Here we used a visual search paradigm to test if one class of social cues transmitted by faces-direction of another's attention as conveyed by gaze direction and head orientation-is perceived more rapidly in personally familiar faces than in unfamiliar faces. We found a strong effect of familiarity on the detection of these social cues, suggesting that the times to process these signals in familiar faces are markedly faster than the corresponding processing times for unfamiliar faces. In the light of these new data, hypotheses on the organization of the visual system for processing faces are formulated and discussed. PMID:25228873

  18. Facilitated detection of social cues conveyed by familiar faces

    PubMed Central

    Visconti di Oleggio Castello, Matteo; Guntupalli, J. Swaroop; Yang, Hua; Gobbini, M. Ida

    2014-01-01

    Recognition of the identity of familiar faces in conditions with poor visibility or over large changes in head angle, lighting and partial occlusion is far more accurate than recognition of unfamiliar faces in similar conditions. Here we used a visual search paradigm to test if one class of social cues transmitted by faces—direction of another's attention as conveyed by gaze direction and head orientation—is perceived more rapidly in personally familiar faces than in unfamiliar faces. We found a strong effect of familiarity on the detection of these social cues, suggesting that the times to process these signals in familiar faces are markedly faster than the corresponding processing times for unfamiliar faces. In the light of these new data, hypotheses on the organization of the visual system for processing faces are formulated and discussed. PMID:25228873

  19. Vibration analysis methods for piping

    NASA Astrophysics Data System (ADS)

    Gibert, R. J.

    1981-09-01

    Attention is given to flow vibrations in pipe flow induced by singularity points in the piping system. The types of pressure fluctuations induced by flow singularities are examined, including the intense wideband fluctuations immediately downstream of the singularity and the acoustic fluctuations encountered in the remainder of the circuit, and a theory of noise generation by unsteady flow in internal acoustics is developed. The response of the piping systems to the pressure fluctuations thus generated is considered, and the calculation of the modal characteristics of piping containing a dense fluid in order to obtain the system transfer function is discussed. The TEDEL program, which calculates the vibratory response of a structure composed of straight and curved pipes with variable mechanical characteristics forming a three-dimensional network by a finite element method, is then presented, and calculations of fluid-structural coupling in tubular networks are illustrated.

  20. Flexible ultrasonic pipe inspection apparatus

    SciTech Connect

    Jenkins, Charles F.; Howard, Boyd D.

    1998-01-01

    A flexible, modular ultrasonic pipe inspection apparatus, comprising a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present.

  1. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  2. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  3. Seismic piping test and analysis

    SciTech Connect

    Not Available

    1980-09-01

    This report presents selected results to date of a dynamic testing and analysis program focusing on a piping system at Consolidated Edison Company of New York's Indian Point-1 Nuclear Generating Station. The goal of this research program is the development of more accurate and realistic models of piping systems subjected to seismic, hydraulic, operating, and other dynamic loads. The program seeks to identify piping system properties significant to dynamic response rather than seeking to simulate any particular form of excitation. The fundamental experimental approach is the excitation of piping/restraint devices/supports by a variety of dynamic test methods and the analysis of the resulting response to identify the characteristic dynamic properties of the system tested. The comparison of the identified dynamic properties to those predicted by alternative analytical approaches will support improvements in methods used in the dynamic analysis of piping, restraint, devices, and supports.

  4. Advances in pipe prover technology

    SciTech Connect

    Jakubenas, P.P.

    1996-09-01

    The petroleum industry has used pipe provers for on line calibration of liquid flow meters for over 30 years. Recently a number of innovations have come to the forefront that enhance the reliability of pipe provers, reduce their size, make them more accurate, and increase their value to the end users. With the widespread use of turbine meters for custody transfer, accurate measurement is more dependent on frequent proving, thus the industry will continue to demand advanced provers and proving techniques. The author will discuss the aforementioned subject with regard to both bidirectional and unidirectional pipe provers. A description of the operational principles of pipe provers and the enhancements that are now available in terms of prover mechanical configuration and electronic instrumentation will be described in detail. In addition, information will be provided concerning integration of pipe provers into measurement systems and design and use of sophisticated computer control systems for automated proving.

  5. Detection of pulsation effects on turbine meters by pulse period modulation measurements

    SciTech Connect

    McKee, R.J.

    1995-12-31

    The objective of the research described in this paper is to evaluate the pulse period modulation method as a potential approach for meeting the gas industries needs for detection of pulsation effects on turbine meters at field installations. Research has been conducted as part of the Gas Research Institute Metering Research Program in response to knowledge that pulsation causes over registration of flow in some cases while not causing any errors in other apparently similar pulsating conditions. Operators need to be able to detect when pulsation is causing significant errors. Methods of detection based on existing theory rely on measuring velocity modulation which is not practical at typical natural gas metering sites. The proposed new method replaces velocity modulation measurements with a monitoring of pulse period modulations that are related to rotor speed changes that result from pulsating flow. Test results indicate that for the tested turbine meters there is an approximate relationship between period modulation and velocity modulation in which period modulation increases as pulsation induced error increases. There are unavoidable uncertainties in quantifying pulse period modulation such that an accurate determination of pulsation effects from period modulation can not be made. However, the presence of a significant error due to pulsation can be detected as a change in the pulse period modulation level.

  6. Time series and correlation of pulsations observed simultaneously by two aircraft

    SciTech Connect

    Ochadlick, A.R. Jr.

    1990-10-01

    Geomagnetic pulsations are an interesting and ubiquitous component of the geomagnetic field and they have been studied extensively for several decades. Numerous comparisons have been made of pulsations at a variety of sites for various objectives. However, conductivity anomalies introduce a number of complexities into the interpretations of pulsations at ground sites through the action of the primary fields on the electrical properties of the local geologic structure. To avoid the difficulties associated with conductivity irregularities, Ochadlick et al. (1985) described an aeromagnetic approach using two aircraft for studying the relationship between pulsations observed over a deep ocean area. Relative to land regions, a deep sea is presumably a more uniform conductor. Using the dual aeromagnetic results, Ochadlick found that the correlation coefficient of pulsations remained relatively constant for observation points spaced apart from a few to about 150 km. Beyond 150 km the correlation coefficient was found to decrease. This letter summarizes the time series records of pulsations, totaling about 9 h, acquired during several dual aircraft flights performed between 20 May and 15 Aug 1985 and presents the associated correlation coefficient between the dual aircraft data sets. Apparently, those measurements show for the first time that a strong similarity of pulsations weakens quickly at a distance of {approximately}150 km which is remarkably close to the ionospheric height and is thus suggestive of a strong ionospheric control on the spatial coherence of pulsations.

  7. Radial stellar pulsation and three-dimensional convection. III. Comparison of two-dimensional and three-dimensional convection effects on radial pulsation

    SciTech Connect

    Geroux, Christopher M.; Deupree, Robert G.

    2014-03-10

    We have developed a multi-dimensional radiation hydrodynamics code to simulate the interaction of radial stellar pulsation and convection for full-amplitude pulsating models. Convection is computed using large eddy simulations. Here, we perform three-dimensional (3D) simulations of RR Lyrae stars for comparison with previously reported 2D simulations. We find that the time-dependent behavior of the peak convective flux on pulsation phase is very similar in both the 2D and 3D calculations. The growth rates of the pulsation in the 2D calculations are about 0.1% higher than in the 3D calculations. The amplitude of the light curve for a 6500 K RR Lyrae model is essentially the same for our 2D and 3D calculations, as is the rising light curve. There are differences in the slope at various times during falling light.

  8. Technology for concrete pipe manipulator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Dan; Lin, Renzhi

    2010-01-01

    The pipe manipulator is a developing mechatronic system to enhance productivity and protects workers from cave-ins in the trench while excavating and laying pipe. The pipe manipulator is for installing concrete pipe into the trench. It is an optical-electro-mechanical system. The mechanism is make up of two parts, the upside and underside. The upside is for lifting the equipment by backhoe and rotating the underside mechanism. It includes rigidity lift beams, holding pad, four-bar linkages, hydraulic cylinder, rotating support, and rotating mechanism. Holding pad will press the bucket back to keep the bucket hooking the pipe man safely and stably. The underside mechanism is for lifting, holding and adjusting the pipe section's stance. The underside mechanism includes support trolley, and lift fork. The support trolley is driven by hydraulic cylinder for moving the fork forward or backward while laying a pipe into trench. The fork is with a self-lock mechanism for preventing the pipe from slide out of the prongs. A new photoelectric locating system is developed for auto-measuring the installing pipe section's stance within the work area. The laser target has been developed as a key part in the photoelectric locating systems. The photoelectric target is a rotating polar coordinate. Photodiodes are used for making the polar radius. There is an angular displacement sensor sitting on the heart-axis of the target for measuring angle of the target rotating. The pipe manipulator can be located by the system, and the locating methods have been presented at last of the paper.

  9. Technology for concrete pipe manipulator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Dan; Lin, Renzhi

    2009-12-01

    The pipe manipulator is a developing mechatronic system to enhance productivity and protects workers from cave-ins in the trench while excavating and laying pipe. The pipe manipulator is for installing concrete pipe into the trench. It is an optical-electro-mechanical system. The mechanism is make up of two parts, the upside and underside. The upside is for lifting the equipment by backhoe and rotating the underside mechanism. It includes rigidity lift beams, holding pad, four-bar linkages, hydraulic cylinder, rotating support, and rotating mechanism. Holding pad will press the bucket back to keep the bucket hooking the pipe man safely and stably. The underside mechanism is for lifting, holding and adjusting the pipe section's stance. The underside mechanism includes support trolley, and lift fork. The support trolley is driven by hydraulic cylinder for moving the fork forward or backward while laying a pipe into trench. The fork is with a self-lock mechanism for preventing the pipe from slide out of the prongs. A new photoelectric locating system is developed for auto-measuring the installing pipe section's stance within the work area. The laser target has been developed as a key part in the photoelectric locating systems. The photoelectric target is a rotating polar coordinate. Photodiodes are used for making the polar radius. There is an angular displacement sensor sitting on the heart-axis of the target for measuring angle of the target rotating. The pipe manipulator can be located by the system, and the locating methods have been presented at last of the paper.

  10. Radial Stellar Pulsation and Three-dimensional Convection. I. Numerical Methods and Adiabatic Test Cases

    NASA Astrophysics Data System (ADS)

    Geroux, Chris M.; Deupree, Robert G.

    2011-04-01

    We are developing a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light and velocity curves. Previous two-dimensional calculations were prevented from doing this because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We remove this difficulty by defining our coordinate system flow algorithm to require that the mass in a spherical shell remains constant throughout the pulsation cycle. We perform adiabatic test calculations to show that large amplitude solutions repeat over more than 150 pulsation periods. We also verify that the computational method conserves the peak kinetic energy per period, as must be true for adiabatic pulsation models.

  11. Lattice Boltzmann Simulation of One Particle Migrating in a Pulsating Flow in Microvessel

    NASA Astrophysics Data System (ADS)

    Qiu, Bing; Tan, Hui-Li; Li, Hua-Bing

    2011-10-01

    A lattice Boltzmann model of two dimensions is used to simulate the movement of a single rigid particle suspended in a pulsating flow in micro vessel. The particle is as big as a red blood cell, and the micro vessel is four times as wide as the diameter of the particle. It is found that Segré—Silberberg effect will not respond to the pulsation of the flow when the Reynolds number is relatively high. However, when the Reynolds number is low enough, Segré—Silberberg effect disappears. In the steady flow, different initial position leads to different equilibrium positions. In a pulsating flow, different frequencies of pulsation also cause different equilibrium positions. Particularly, when the frequency of pulsation is closed to the human heart rate, Segré—Silberberg effect presents again. The evolutions of velocity, rotation, and trajectory of the particle are investigated to find the dynamics of such abnormal phenomenon.

  12. Field and thermal plasma observations of ULF pulsations during a magnetically disturbed interval

    NASA Technical Reports Server (NTRS)

    Lin, N.; Engebretson, M. J.; Reinleitner, L. A.; Olson, J. V.; Gallagher, D. L.; Cahill, L. J., Jr.; Slavin, J. A.; Persoon, A. M.

    1992-01-01

    A ULF pulsation event is discussed on the basis of experimental observations of electric and magnetic field measurements as well as particle measurements from the DE 1 spacecraft. The observations were made near the magnetic equator in a space covering a large range of L shells and magnetic latitudes, and comparisons are made to ground observations. Azimuthal oscillations are observed following gradually decaying long-period compressional waves. Weak interaction between magnetic shells indicates that the source is probably weak, and ground data on magnetic pulsations showed strong signals that did not necessarily correspond to the quasisinusoidal pulsations observed in space. Azimuthal pulsations observed by the spacecraft indicate that there was a plasma density gradient beyond the plasmapause. The ULF pulsations were probably affected by changes in the magnetic field and solar-wind dynamic pressure, and their periods are found to be linked to geomagnetic latitude.

  13. Results mixed from pulsating flow tests of orifice-plate meters

    SciTech Connect

    Arasi, J.A. )

    1992-10-05

    This paper reports that laboratory tests on several commercially available orifice-plate meters for use in pulsating flow indicate that none yields acceptable accuracy. These tests suggested, however, that if the objective of monitoring pulsating flow is to indicate or quantify pulsation magnitudes for comparisons, then at least two instruments are acceptable. Use of such meters, particularly in low flow rate gathering systems, can be a viable alternative to attempting to reduce the intensity (amplitude and frequency) of pulsation by expensive installation and maintenance of chokes and bottles. Phillips Petroleum Co. set out to find a meter that would be sensitive enough to measure pulsating hydrocarbon flows with acceptable accuracy using the orifice plate. Several orifice measurement systems were simultaneously investigated at the Southwest Research Institute, San Antonio (SwRI).

  14. RADIAL STELLAR PULSATION AND THREE-DIMENSIONAL CONVECTION. I. NUMERICAL METHODS AND ADIABATIC TEST CASES

    SciTech Connect

    Geroux, Chris M.; Deupree, Robert G.

    2011-04-10

    We are developing a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light and velocity curves. Previous two-dimensional calculations were prevented from doing this because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We remove this difficulty by defining our coordinate system flow algorithm to require that the mass in a spherical shell remains constant throughout the pulsation cycle. We perform adiabatic test calculations to show that large amplitude solutions repeat over more than 150 pulsation periods. We also verify that the computational method conserves the peak kinetic energy per period, as must be true for adiabatic pulsation models.

  15. V2653 Ophiuchii with a pulsating component and Ppuls - Porb, Ppuls - g correlations for γ Dor type pulsators

    NASA Astrophysics Data System (ADS)

    Çakırlı, Ö.; Ibanoglu, C.

    2016-05-01

    We present new spectroscopic observations of the double-lined eclipsing binary V2653 Ophiuchii. The photometric observations obtained by ASAS were analyzed and combined with the analysis of radial velocities for deriving the absolute parameters of the components. Masses and radii were determined for the first time as Mp = 1.537 ± 0.021 M⊙ and Rp = 2.215 ± 0.055 R⊙, Ms = 1.273 ± 0.019 M⊙ and Rs = 2.000 ± 0.056 R⊙ for the components of V2653 Oph. We estimate an interstellar reddening of 0.15 ± 0.08 mag and a distance of 300 ± 50 pc for the system, both supporting the membership of the open cluster Collinder 359. Using the out-of-eclipse photometric data we have made frequency analysis and detected a periodic signal at 1.0029 ± 0.0019 c/d. This frequency and the location of the more massive star on the HR diagram lead to classification of a γ Dor type variable. Up to date only eleven γ Dor type pulsators in the eclipsing binaries have been discovered. For six out of 11 systems, the physical parameters were determined. Although a small sample, we find empirical relations that Ppuls ∝ Porb0.43 and Ppuls ∝ g-0.83. While the pulsation periods increase with longer orbital periods, they decrease with increasing surface gravities of pulsating components and gravitational pull exerted by the companions. We present, briefly, the underlying physics behind the correlations we derived.

  16. Ventricular dilation and elevated aqueductal pulsations in a new experimental model of communicating hydrocephalus

    SciTech Connect

    Wagshul, M.; Smith, S.; Wagshul, M.; McAllister, J.P.; Rashid, S.; Li, J.; Egnor, M.R.; Walker, M.L.; Yu, M.; Smith, S.D.; Zhang, G.; Chen, J.J.; Beneveniste, H.

    2009-03-01

    In communicating hydrocephalus (CH), explanations for the symptoms and clear-cut effective treatments remain elusive. Pulsatile flow through the cerebral aqueduct is often significantly elevated, but a clear link between abnormal pulsations and ventriculomegaly has yet to be identified. We sought to demonstrate measurement of pulsatile aqueductal flow of CSF in the rat, and to characterize the temporal changes in CSF pulsations in a new model of CH. Hydrocephalus was induced by injection of kaolin into the basal cisterns of adult rats (n = 18). Ventricular volume and aqueductal pulsations were measured on a 9.4 T MRI over a one month period. Half of the animals developed ventricular dilation, with increased ventricular volume and pulsations as early as one day post-induction, and marked chronic elevations compared to intact controls (volume: 130.15 {+-} 83.21 {mu}l vs. 15.52 {+-} 2.00 {mu}l; pulsations: 114.51 nl {+-} 106.29 vs. 0.72 {+-} 0.13 nl). Similar to the clinical presentation, the relationship between ventricular size and pulsations was quite variable. However, the pulsation time-course revealed two distinct sub-types of hydrocephalic animals: those with markedly elevated pulsations which persisted over time, and those with mildly elevated pulsations which returned to near normal levels after one week. These groups were associated with severe and mild ventriculomegaly respectively. Thus, aqueductal flow can be measured in the rat using high-field MRI and basal cistern-induced CH is associated with an immediate change in CSF pulsatility. At the same time, our results highlight the complex nature of aqueductal pulsation and its relationship to ventricular dilation.

  17. Characterization of ultra low frequency (ULF) pulsations and the investigation of their possible source

    NASA Astrophysics Data System (ADS)

    Mthembu, S. H.; Malinga, S. B.; Walker, A. D. M.; Magnus, L.

    2009-08-01

    In this paper we present the results from the observation of ultra low frequency (ULF) pulsations in the Doppler velocity data from SuperDARN HF radar located at Goose Bay (61.94° N, 23.02° E, geomagnetic). Fourier spectral techniques were used to determine the spectral content of the data and the results show Pc 5 ULF pulsations (with a frequency range of 1 to 4 mHz) where the magnetic field lines were oscillating at discrete frequencies of about 1.3 and 1.9 mHz. These pulsations are classified as field lines resonance (FLR) since the 1.9 mHz component exhibited an enhancement in amplitude with an associated phase change of approximately 180° across a resonance latitude of 71.3°. The spatial and temporal structure of the ULF pulsations was examined by investigating their instantaneous amplitude which was calculated as the amplitude of the analytic signal. The results presented a full field of view which exhibit pulsations activity simultaneously from all beams. This representation shows that the peak amplitude of the 1.9 mHz component was observed over the longitudinal range of 13°. The temporal structure of the pulsations was investigated from the evolution of the 1.9 mHz component and the results showed that the ULF pulsations had a duration of about 1 h. Wavelet analysis was used to investigate solar wind as a probable source of the observed ULF pulsations. The time delay compared well with the solar wind travel time estimates and the results suggest a possible link between the solar wind and the observed pulsations. The sudden change in dynamic pressure also proved to be a possible source of the observed ULF pulsations.

  18. Pressure pulsation in roller pumps: a validated lumped parameter model.

    PubMed

    Moscato, Francesco; Colacino, Francesco M; Arabia, Maurizio; Danieli, Guido A

    2008-11-01

    During open-heart surgery roller pumps are often used to keep the circulation of blood through the patient body. They present numerous key features, but they suffer from several limitations: (a) they normally deliver uncontrolled pulsatile inlet and outlet pressure; (b) blood damage appears to be more than that encountered with centrifugal pumps. A lumped parameter mathematical model of a roller pump (Sarns 7000, Terumo CVS, Ann Arbor, MI, USA) was developed to dynamically simulate pressures at the pump inlet and outlet in order to clarify the uncontrolled pulsation mechanism. Inlet and outlet pressures obtained by the mathematical model have been compared with those measured in various operating conditions: different rollers' rotating speed, different tube occlusion rates, and different clamping degree at the pump inlet and outlet. Model results agree with measured pressure waveforms, whose oscillations are generated by the tube compression/release mechanism during the rollers' engaging and disengaging phases. Average Euclidean Error (AEE) was 20mmHg and 33mmHg for inlet and outlet pressure estimates, respectively. The normalized AEE never exceeded 0.16. The developed model can be exploited for designing roller pumps with improved performances aimed at reducing the undesired pressure pulsation.

  19. Numerical simulation of pressure pulsations in Francis turbines

    NASA Astrophysics Data System (ADS)

    Magnoli, M. V.; Schilling, R.

    2012-11-01

    In the last decades, hydraulic turbines have experienced the increase of their power density and the extension of their operating range, leading the fluid and mechanical dynamic effects to become significantly more pronounced. The understanding of the transient fluid flow and of the associated unsteady effects is essential for the reduction of the pressure pulsation level and improvement of the machine dynamic behaviour. In this study, the instationary fluid flow through the complete turbine was numerically calculated for an existing Francis machine with high specific speed. The hybrid turbulence models DES (detached eddy simulation) and SAS (scale adaptive simulation) allowed the accurate simulation of complex dynamic flow effects, such as the rotor-stator-interaction and the draft tube instabilities. Different operating conditions, as full load, part load, higher part load and deep part load, were successfully simulated and showed very tight agreement with the experimental results from the model tests. The transient pressure field history, obtained from the CFD (computational fluid dynamics) simulation and stored for each time step, was used as input for the full instationary FEA (finite element analysis) of turbine components. The assessment of the machine dynamic motion also offered the possibility to contribute to the understanding of the pressure pulsation effects and to further increase the turbine stability. This research project was developed at the Institute of Fluid Mechanics of the TU München.

  20. Pulsations of rapidly rotating stars with compositional discontinuities

    NASA Astrophysics Data System (ADS)

    Reese, Daniel R.; Lara, Francisco Espinosa; Rieutord, Michel

    2014-02-01

    Recent observations of rapidly rotating stars have revealed the presence of regular patterns in their pulsation spectra. This has raised the question as to their physical origin, and, in particular, whether they can be explained by an asymptotic frequency formula for low-degree acoustic modes, as recently discovered through numerical calculations and theoretical considerations. In this context, a key question is whether compositional/density gradients can adversely affect such patterns to the point of hindering their identification. To answer this question, we calculate frequency spectra using two-dimensional ESTER stellar models. These models use a multi-domain spectral approach, allowing us to easily insert a compositional discontinuity while retaining a high numerical accuracy. We analyse the effects of such discontinuities on both the frequencies and eigenfunctions of pulsation modes in the asymptotic regime. We find that although there is more scatter around the asymptotic frequency formula, the semi-large frequency separation can still be clearly identified in a spectrum of low-degree acoustic modes.