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Sample records for pipes conveying pulsating

  1. Vibration of a Flexible Pipe Conveying Viscous Pulsating Fluid Flow

    NASA Astrophysics Data System (ADS)

    GORMAN, D. G.; REESE, J. M.; ZHANG, Y. L.

    2000-02-01

    The non-linear equations of motion of a flexible pipe conveying unsteadily flowing fluid are derived from the continuity and momentum equations of unsteady flow. These partial differential equations are fully coupled through equilibrium of contact forces, the normal compatibility of velocity at the fluid- pipe interfaces, and the conservation of mass and momentum of the transient fluid. Poisson coupling between the pipe wall and fluid is also incorporated in the model. A combination of the finite difference method and the method of characteristics is employed to extract displacements, hydrodynamic pressure and flow velocities from the equations. A numerical example of a pipeline conveying fluid with a pulsating flow is given and discussed.

  2. Predicting phase shift effects for vibrating fluid-conveying pipes due to Coriolis forces and fluid pulsation

    NASA Astrophysics Data System (ADS)

    Enz, Stephanie; Thomsen, Jon Juel

    2011-10-01

    Knowing the influence of fluid flow perturbations on the dynamic behavior of fluid-conveying pipes is of relevance, e.g., when exploiting flow-induced oscillations of pipes to determine the fluids mass flow or density, as done with Coriolis flow meters (CFM). This could be used in the attempts to improve accuracy, precision, and robustness of CFMs. A simple mathematical model of a fluid-conveying pipe is formulated and the effect of pulsating fluid flow is analyzed using a multiple time scaling perturbation analysis. The results are simple analytical predictions for the transverse pipe displacement and approximate axial shift in vibration phase. The analytical predictions are tested against pure numerical solution using representative examples, showing good agreement. Fluid pulsations are predicted not to influence CFM accuracy, since proper signal filtering is seen to allow the determination of the correct mean phase shift. Large amplitude motions, which could influence CFM robustness, do not appear to be induced by the investigated fluid pulsation. Pulsating fluid of the combination resonance type could, however, influence CFMs robustness, if induced pipe motions go unnoticed and uncontrolled during CFM operation by feedback control. The analytical predictions offer an immediate insight into how fluid pulsation affects phase shift, which is a quantity measured by CFMs to estimate the mass flow, and lead to hypotheses for more complex geometries, i.e. industrial CFMs. The validity of these hypotheses is suggested to be tested using laboratory experiments, or detailed computational models taking fluid-structure interaction into account.

  3. Dynamics and stability of pipes conveying fluid

    SciTech Connect

    Chang, C.O. . Inst. of Applied Mechanics); Chen, K.C. )

    1994-02-01

    This paper deals with the dynamics and stability of simply supported pipes conveying fluid, where the fluid has a small harmonic component of flow velocity superposed on a constant mean value. The perturbation techniques and the method of averaging are used to convert the nonautonomous system into an autonomous one and determine the stability boundaries. Post-bifurcation analysis is performed for the parametric points in the resonant regions where the axial force, which is induced by the transverse motion of the pipe due to the fixed-span ends and contributes nonlinearities to the equations of motion, is included. For the undamped system, linear analysis is inconclusive about stability and there does not exist nontrivial solution in the resonant regions. For the damped system, it is found that the original stable system remains stable when the pulsating frequency increased cross the stability boundary and becomes unstable when the pulsating frequency decreases across the stability boundary. Practical applications of such a problem are vibrations of heat exchangers, liquid-fuel rocket piping, and nuclear reactor coolant channels.

  4. Pipes Conveying Fluid: A Model Dynamical Problem

    NASA Astrophysics Data System (ADS)

    Païdoussis, M. P.; Li, G. X.

    1993-02-01

    This paper reviews the dynamics of pipes conveying fluid and presents a selective review of the research undertaken on it. It is endeavoured to show that this system is fast becoming a new paradigm in dynamics, on a par with, for instance, the classical problem of the column subjected to compressive loading, but one capable of displaying much richer dynamical behaviour. The dynamics of pipes with supported ends, cantilevered pipes or with unusual boundary conditions; continuously flexible pipes or articulated ones; pipe conveying incompressible or compressible fluid, with steady or unsteady flow velocity; pipes thin enough to be treated as thin shells; linear, nonlinear and chaotic dynamics; these and many more are some of the aspects of the problem considered. An Appendix is provided for those unfamiliar with the modern methods of nonlinear analysis.

  5. 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.

  6. 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.

  7. 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).

  8. 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.

  9. 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.

  10. Pulsating laminar fully developed channel and pipe flows.

    PubMed

    Haddad, Kais; Ertunç, Ozgür; Mishra, Manoranjan; Delgado, Antonio

    2010-01-01

    Analytical investigations are carried out on pulsating laminar incompressible fully developed channel and pipe flows. An analytical solution of the velocity profile for arbitrary time-periodic pulsations is derived by approximating the pulsating flow variables by a Fourier series. The explicit interdependence between pulsations of velocity, mass-flow rate, pressure gradient, and wall shear stress are shown by using the proper dimensionless parameters that govern the flow. Utilizing the analytical results, the scaling laws for dimensionless pulsation amplitudes of the velocity, mass-flow rate, pressure gradient, and wall shear stress are analyzed as functions of the dimensionless pulsation frequency. Special attention has been given to the scaling laws describing the flow reversal phenomenon occurring in pulsating flows, such as the condition for flow reversal, the dependency of the reversal duration, and the amplitude. It is shown that two reversal locations away from the wall can occur in pulsating flows in pipes and channels and the reversed amount of mass per period reaches a maximum at a certain dimensionless frequency for a given amplitude of mass-flow rate fluctuations. These analyses are numerically conducted for pipe and channel flows over a large frequency range in a comparative manner. PMID:20365456

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Absolute and Convective Instability in Fluid-Conveying Flexible Pipes

    NASA Astrophysics Data System (ADS)

    de Langre, E.; Ouvrard, A. E.

    1998-11-01

    The effect of internal plug flow on the lateral stability of fluid conveying flexible pipes is investigated by determining the absolute/convective nature of the instability from the analytically derived linear dispersion relation. The fluid-structure interaction is modeled following the work of Gregory and Paidoussis (1966). The different domains of stability, convective instability, and absolute instability are explicitly derived in parameter space. The effect of flow velocity, mass ratio between the fluid and the structure, stiffness of the elastic foundation and axial tension is considered. Absolute instability prevails over a wide range of parameters. Convective instability only takes place at very high mass ratio, small stiffness and small axial tension. Relation is made with previous work of Brazier-Smith & Scott (1984) and Crighton (1991), considered here as a short wave approximation.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Pressure pulsations in piping system excited by a centrifugal turbomachinery taking the damping characteristics into consideration

    NASA Astrophysics Data System (ADS)

    Hayashi, I.; Kaneko, S.

    2014-02-01

    Pressure pulsations excited by a centrifugal turbomachinery such as compressor, fan or pump at the blade passing frequency may cause severe noise and vibrations in piping system. Therefore, the practical evaluation method of pressure pulsations is strongly recommended. In particular, the maximum pressure amplitude under the resonant conditions should be appropriately evaluated. In this study, a one-dimensional excitation source model for a compressor or pump is introduced based on the equation of motion, so as to incorporate the non-linear damping proportional to velocity squared in the total piping system including the compressor or pump. The damping characteristics of the compressor or pump are investigated by using the semi-empirical model. It is shown that the resistance coefficient of the compressor or pump depends on the Reynolds number that is defined using the equivalent velocity of the pulsating flow. The frequency response of the pressure amplitude and the pressure distribution in the piping system can be evaluated by introducing the equivalent resistance of the compressor or pump and that of piping system. In particular, the relation of the maximum pressure amplitude in piping system to the location of the excitation source under resonant conditions can be evaluated. Finally, the reduction of the pressure pulsations by use of an orifice plate is discussed in terms of the pulsation energy loss.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Robust flutter control of a vertical pipe conveying fluid using gyroscopic mechanism

    SciTech Connect

    Cui, H.; Qiu, J.; Tani, J.

    1995-12-01

    This paper presents a study on the flutter suppression of a cantilevered pipe conveying fluid by means of gyroscopic mechanism. One end of the pipe is fixed at the center of the gyroscopic mechanism and the two directional vibration of the pipe is controlled by the moments of two servomotors connected to the two axes of the gyroscopic mechanism. The present system with the servomotors is described approximately by two independent differential equations. The evaluation method of structured singular value is used to obtain a robust controller, and the unformulated dynamics (coupled motion of two directions, nonlinear effect etc.) is treated by the robust performance of controller. Numerical simulation and experimental results show that the flutter is effectively suppressed by the present method.

  14. 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.

  15. Temperature modulation of the vibrational responses of a flexible fluid-conveying pipe

    NASA Astrophysics Data System (ADS)

    Adelaja, Adekunle

    2013-12-01

    In this study, the nonlinear transverse vibration of a flexible pipe conveying hot, pressurized fluid is investigated. The pipe which is subjected to a pinned-pinned end condition extends as a result of several operating variables such as internal fluid temperature variation, pre-stress and internal pressurization. The equation of motion is solved analytically by hybrid Fourier-Laplace transforms, and the effects of inlet temperature, temperature gradient, and coefficient of area deformation are investigated on the natural frequencies and transverse dynamic response of the pipeline. While the inlet temperature and temperature gradient are found to be inversely proportional to the natural frequencies and amplitude of the dynamic response, increase in the coefficient of area deformation has little effect on the natural frequencies for the particular case considered.

  16. Chaotic oscillations of the autonomous system of a constrained pipe conveying fluid

    NASA Astrophysics Data System (ADS)

    Païdoussis, M. P.; Li, G. X.; Moon, F. C.

    1989-11-01

    Experiments have shown that a cantilevered pipe conveying fluid, the limit-cycle motions of which (beyond the Hopf bifurcation) interact with motion-limiting non-linear constraints, exhibits region of chaotic motions. In this paper the planar dynamics of the flexible pipe system are examined theoretically by means of a two-degree-of-freedom (four-dimensional) analytical model, exploring the existence of chaotic oscillations in the parameter space of this autonomous system. Calculations of the Lyapunov exponents, phase portraits of the oscillation, bifurcation diagrams and Poincaré maps establish definitively the existence of chaotic motions. The route to chaos is shown to be via period-doubling bifurcations. The effect of some key parameters on the chaotic regions is investigated.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:22493853

  7. 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.

  8. A new time-domain drag description and its influence on the dynamic behaviour of a cantilever pipe conveying fluid

    NASA Astrophysics Data System (ADS)

    Kuiper, G. L.; Metrikine, A. V.; Battjes, J. A.

    2007-04-01

    Studying dynamic stability of a vertically suspended, fully submerged pipe conveying fluid upwards, researchers have found a contradiction between theoretical predictions and experiments. Experiments did not show any instability, while theory predicts instability at infinitesimally low fluid velocities for a pipe without dissipation mechanisms. To explain this contradiction, in 2005 Païdoussis and co-workers postulated a new description of the boundary condition at the free end of the pipe. Subject to this boundary condition the pipe is predicted to become unstable by divergence (stable node to saddle bifurcation) at a velocity higher than yet achieved in experiments. In this paper, it is shown that a realistic description of hydrodynamic drag in combination with conventional boundary conditions might result in even higher critical velocity, and hence, this could also be an explanation of the contradiction. The description of the hydrodynamic drag is based on experimental data available in literature. This data has been obtained by experimenting with submerged rigid cylinders. To make it applicable to flexible pipes, a key step is undertaken in this paper to translate the data from the frequency domain to the time domain. Using the time-domain description of the hydrodynamic drag in combination with the conventional boundary conditions at the free end, it is shown that the pipe becomes unstable by flutter (stable focus to unstable focus bifurcation) at a critical velocity, which is much higher than that attainable in small-scale experiments. For fluid velocities exceeding the critical one, the pipe motion reaches a steady oscillation of finite amplitude, i.e. a stable limit cycle.

  9. 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.

  10. 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.

  11. 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.

  12. 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. PMID:22820681

  13. Research on Resistance Properties for Dense Phase Pneumatic Conveying of Pulverized Coal in Vertical Pipe at Different Pressures

    NASA Astrophysics Data System (ADS)

    Pu, Wenhao; Zhao, Changsui; Xiong, Yuanquan; Liang, Cai; Chen, Xiaoping; Fan, Chunlei; Lu, Peng

    2007-06-01

    Experiments on pressure drops in vertical pipe in dense-phase pulverized coal pneumatic conveying system were conducted under the pressure range from 2.1 MPa to 3.6 MPa. The nitrogen, as conveying gas, was introduced into the system via a header connected with sixteen nitrogen cylinders. Gas flow rate was controlled with a needle valve, and three flow meters were used to measure the volume flow rate of nitrogen. The dosing hopper was suspended on three load cells, which enable on-line weighing the solids collected in the hopper. Pressures and pressure drops were measured with pressure transducers and KELLER differential pressure transducers, respectively. All the signals were connected to a computer. Sampling time interval was from 5 milliseconds to 1 second. The experimental results indicate that at the pressure range from 2.1 MPa to 3.6 MPa when the solids mass flow rate is kept constant and the superficial velocity increases, the pressure gradient first decreases, then starts to increase and when the solids mass flow rate and superficial velocity is constant, the pressure gradient increases as the transport pressure is increased. Based on Barth's pneumatic conveying theory, an empirical correlation of the additional pressure drop coefficient in vertical pipe with Froude number and the solid/gas density ratio was proposed under different pressure. Comparing the pressure drops predicted by the correlation with the experimental data under the pressure of 2.13MPa, it is found that the calculation results are in good agreement with the experimental data.

  14. Non-Planar Vibrations of a Pipe Conveying Fluid with a Spring-Supported End

    NASA Astrophysics Data System (ADS)

    Yamashita, Kiyotaka; Yoshizawa, Masatsugu; Hirose, Yuuki; Taniguchi, Akira

    A theoretical and experimental investigation was conducted into the spatial behavior of a flexible pipe through which fluid flows and which is built-in at one end and has an asymmetric spring-support at the other end. Planar, non-planar and beating type vibrations occur in such a system and depend on the flow velocity and spring coefficients. Equations governing amplitudes and the phase were derived and used to clarify numerically the above specific cases. Corresponding actual pipe displacements were then measured experimentally using an image processing system employing two CCD cameras. Qualitative agreement was demonstrated between the experimental and theoretical results.

  15. 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.

  16. 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%.

  17. 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.

  18. Gas compressor with side branch absorber for pulsation control

    SciTech Connect

    Harris, Ralph E.; Scrivner, Christine M.; Broerman, III, Eugene L.

    2011-05-24

    A method and system for reducing pulsation in lateral piping associated with a gas compressor system. A tunable side branch absorber (TSBA) is installed on the lateral piping. A pulsation sensor is placed in the lateral piping, to measure pulsation within the piping. The sensor output signals are delivered to a controller, which controls actuators that change the acoustic dimensions of the SBA.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Industrial application of ultrasound based in-line rheometry: From stationary to pulsating pipe flow of chocolate suspension in precrystallization process

    NASA Astrophysics Data System (ADS)

    Ouriev, Boris; Windhab, Erich; Braun, Peter; Birkhofer, Beat

    2004-10-01

    In-line visualization and on-line characterization of nontransparent fluids becomes an important subject for process development in food and nonfood industries. In our work, a noninvasive Doppler ultrasound-based technique is introduced. Such a technique is applied for investigation of nonstationary flow in the chocolate precrystallization process. Unstable flow conditions were induced by abrupt flow interruption and were followed up by strong flow pulsations in the piping system. While relying on available process information, such as absolute pressures and temperatures, no analyses of flow conditions or characterization of suspension properties could possibly be done. It is obvious that chocolate flow properties are sensitive to flow boundary conditions. Therefore, it becomes essential to perform reliable structure state monitoring and particularly in application to nonstationary flow processes. Such flow instabilities in chocolate processing can often lead to failed product quality with interruption of the mainstream production. As will be discussed, a combination of flow velocity profiles, on-line fit into flow profiles, and pressure difference measurement are sufficient for reliable analyses of fluid properties and flow boundary conditions as well as monitoring of the flow state. Analyses of the flow state and flow properties of chocolate suspension are based on on-line measurement of one-dimensional velocity profiles across the flow channel and their on-line characterization with the power-law model. Conclusions about flow boundary conditions were drawn from a calculated velocity standard mean deviation, the parameters of power-law fit into velocity profiles, and volumetric flow rate information.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Pulsation effects on the air fuel ratio of carburetor engines

    SciTech Connect

    Tanaka, M.; Sato, T.; Watanabe, K.

    1986-01-01

    A significant wavewise change of air fuel ratio in line with the engine speed having a long intake pipe was studied experimentally and theoretically. The results show the pulsewise change in fuel flow plays the dominant role in the wavewise change in the air fuel ratio. It is found that this pulsewise fluctuation of the fuel flow forms an oscillation wave with both the amplitude and frequency becoming larger according to the engine speed resulted by the phase change of the pulsation wave in the intake pipe according to the engine speed. A modified frequency ratio of gas vibration in the intake pipe to that of engine intake stroke is proposed to explain this pulsation effect on the fuel flow and an effective simulator for this phenomena is established.

  13. Interaction Between Convection and Pulsation

    NASA Astrophysics Data System (ADS)

    Houdek, Günter; Dupret, Marc-Antoine

    2015-12-01

    This article reviews our current understanding of modelling convection dynamics in stars. Several semi-analytical time-dependent convection models have been proposed for pulsating one-dimensional stellar structures with different formulations for how the convective turbulent velocity field couples with the global stellar oscillations. In this review we put emphasis on two, widely used, time-dependent convection formulations for estimating pulsation properties in one-dimensional stellar models. Applications to pulsating stars are presented with results for oscillation properties, such as the effects of convection dynamics on the oscillation frequencies, or the stability of pulsation modes, in classical pulsators and in stars supporting solar-type oscillations.

  14. Pulsating aurora: Source region & morphology

    NASA Astrophysics Data System (ADS)

    Jaynes, Allison

    Pulsating aurora, a common phenomenon in the polar night sky, offers a unique opportunity to study the precipitating particle populations responsible for this subtle yet fascinating display of lights. The conjecture that the source of these electrons originates near the equator, made decades ago, has now been confirmed using in-situ measurements. In this thesis, we present these results that compare the frequencies of equatorial electron flux pulsations and pulsating aurora luminosity fluctuations at the ionospheric footprint. We use simultaneous satellite-based data from GOES 13 and ground-based data from the THEMIS allsky imager array to show that there is a direct correlation between luminosity fluctuations near the ground and particle pulsations in equatorial space; the source region of the pulsating aurora. Pulsating aurora almost exclusively occurs embedded within a region of diffuse aurora. By studying the two particle populations, one can contribute to the theory behind auroral pulsations. The interplay between the two auroral types, and the systems that control them, are not yet well known. We analyze ground optical observations of pulsating aurora events to attempt to characterize the relationship between the two types of auroral precipitation. Pulsating aurora is a significant component of energy transfer within the framework of magnetosphere-ionosphere coupling. Further study of the morphology, total energy deposition, and the pulsation mechanism of pulsating aurora is key to a better understanding of our earth-sun system.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Model reduction for parametric instability analysis in shells conveying fluid

    NASA Astrophysics Data System (ADS)

    Kochupillai, Jayaraj; Ganesan, N.; Padmanabhan, Chandramouli

    2003-05-01

    Flexible pipes conveying fluid are often subjected to parametric excitation due to time-periodic flow fluctuations. Such systems are known to exhibit complex instability phenomena such as divergence and coupled-mode flutter. Investigators have typically used weighted residual techniques, to reduce the continuous system model into a discrete model, based on approximation functions with global support, for carrying out stability analysis. While this approach is useful for straight pipes, modelling based on FEM is needed for the study of complicated piping systems, where the approximation functions used are local in support. However, the size of the problem is now significantly larger and for computationally efficient stability analysis, model reduction is necessary. In this paper, model reduction techniques are developed for the analysis of parametric instability in flexible pipes conveying fluids under a mean pressure. It is shown that only those linear transformations which leave the original eigenvalues of the linear time invariant system unchanged are admissible. The numerical technique developed by Friedmann and Hammond (Int. J. Numer. Methods Eng. Efficient 11 (1997) 1117) is used for the stability analysis. One of the key research issues is to establish criteria for deciding the basis vectors essential for an accurate stability analysis. This paper examines this issue in detail and proposes new guidelines for their selection.

  20. 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 nonsteady 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 with 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.

  1. 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.

  2. 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.

  3. Centrifugal compressor modifications and their effect on high-frequency pipe wall vibration

    SciTech Connect

    Motriuk, R.W.; Harvey, D.P.

    1998-08-01

    High-frequency pulsation generated by centrifugal compressors, with pressure wave-lengths much smaller than the attached pipe diameter, can cause fatigue failures of the compressor internals, impair compressor performance, and damage the attached compressor piping. There are numerous sources producing pulsation in centrifugal compressors. Some of them are discussed in literature at large (Japikse, 1995; Niese, 1976). NGTL has experienced extreme high-frequency discharge pulsation and pipe wall vibration on many of its radial inlet high-flow centrifugal gas compressor facilities. These pulsations led to several piping attachment failures and compressor internal component failures while the compressor operated within the design envelope. This paper considers several pulsation conditions at an NGTL compression facility which resulted in unacceptable piping vibration. Significant vibration attenuation was achieved by modifying the compressor (pulsation source) through removal of the diffuser vanes and partial removal of the inlet guide vanes (IGV). Direct comparison of the changes in vibration, pulsation, and performance are made for each of the modifications. The vibration problem, probable causes, options available to address the problem, and the results of implementation are reviewed. The effects of diffuser vane removal on discharge pipe wall vibration as well as changes in compressor performance are described.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  11. Underground pipe inspection device and method

    DOEpatents

    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.

  12. Flexible Conveyance Control System for Agile Manufacturing

    NASA Astrophysics Data System (ADS)

    Uchiyama, Kazuhisa; Uchimura, Keiichi; Yoshikawa, Takeru; Shishino, Satoru; Hu, Zhencheng

    The control of conveyance between processes still relies on the engineer's experience. It is difficult to correspond to the change in the conveyance layout due to the expansion and reduction of production and the breakdown of conveyance devices. In this paper, we propose a conveyance control system that can adapt to changes in the conveyance layout and we aim at the improvement of the amount of total conveyance. First of all, the system is divided into the part where the conveyance layout is made a data base and the part where the conveyance control that uses the congestion index is done. Therefore, it is possible to deal flexibly by changing the data base part without changing the conveyance control part when it is necessary to change the conveyance layout suddenly. In all the combinations of the conveyance layout and the turning on pattern used as a result of the simulation, the proposed conveyance control method became a great result by the amount of total conveyance.

  13. The Pulsating White Dwarf Stars

    NASA Astrophysics Data System (ADS)

    Fontaine, G.; Brassard, P.

    2008-10-01

    We present a summary of what is currently known about the three distinct families of isolated pulsating white dwarfs. These are the GW Vir stars (He/C/O-atmosphere stars with Teff sime 120,000 K), the V777 Her stars (He-atmosphere, Teff sime 25,000 K), and the ZZ Ceti stars (H-atmosphere, Teff sime 12,000 K), all showing multiperiodic luminosity variations caused by low-order and low-degree g-mode instabilities. We also provide, in an Appendix, a very brief overview of the newly found evidence in favor of the existence of a fourth category of oscillating white dwarfs bearing strong similarities with these families of pulsators. We begin our survey with a short historical introduction, followed by a general discussion of pulsating white dwarfs as compact pulsators. We then discuss the class properties of these objects, including an updated census. We next focus on the instability domains for each family of pulsators in the log g - Teff diagram, and present their time-averaged properties in more detail. This is followed by a section on excitation physics, i.e., the causes of the pulsational instabilities, with emphasis on the common properties of the different types of pulsator. We then discuss the time-dependent properties of the pulsating white dwarfs featuring, among other things, a brief "picture tour" across the ZZ Ceti instability strip. We next review the methods used to infer or constrain the angular geometry of a pulsation mode in a white dwarf. These include multicolor photometry and time-resolved spectroscopy, the exploitation of the nonlinear features in the observed light curves, and rotational splitting. We also consider basic adiabatic asteroseismology starting with a discussion of the reaction of the period spectrum to variations of model parameters. We next review the various asteroseismological inferences that have so far been claimed for white dwarfs. We also discuss the potential of exploiting the rates of period change. We finally provide some

  14. 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.

  15. [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

  16. Synchronization Model for Pulsating Variables

    NASA Astrophysics Data System (ADS)

    Takahashi, S.; Morikawa, M.

    2013-12-01

    A simple model is proposed, which describes the variety of stellar pulsations. In this model, a star is described as an integration of independent elements which interact with each other. This interaction, which may be gravitational or hydrodynamic, promotes the synchronization of elements to yield a coherent mean field pulsation provided some conditions are satisfied. In the case of opacity driven pulsations, the whole star is described as a coupling of many heat engines. In the case of stochastic oscillation, the whole star is described as a coupling of convection cells, interacting through their flow patterns. Convection cells are described by the Lorentz model. In both models, interactions of elements lead to various pulsations, from irregular to regular. The coupled Lorenz model also describes a light curve which shows a semi-regular variability and also shows a low-frequency enhancement proportional to 1/f in its power spectrum. This is in agreement with observations (Kiss et al. 2006). This new modeling method of ‘coupled elements’ may provide a powerful description for a variety of stellar pulsations.

  17. 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.

  18. 36 CFR 17.8 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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...

  19. 36 CFR 17.8 - Conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  20. The Pulsating Pulsar Magnetosphere

    NASA Astrophysics Data System (ADS)

    Tsui, K. H.

    2015-06-01

    Following the basic principles of a charge-separated pulsar magnetosphere, we consider the magnetosphere to be stationary in space, instead of corotating, and the electric field to be uploaded from the potential distribution on the pulsar surface, set up by the unipolar induction. Consequently, the plasma of the magnetosphere undergoes guiding center drifts of the gyromotion due to the forces transverse to the magnetic field. These forces are the electric force, magnetic gradient force, and field line curvature force. Since these plasma velocities are of drift nature, there is no need to introduce an emf along the field lines, which would contradict the {{E}\\parallel }={\\boldsymbol{E}} \\cdot {\\boldsymbol{B}} =0 plasma condition. Furthermore, there is also no need to introduce the critical field line separating the electron and ion open field lines. We present a self-consistent description where the magnetosphere is described in terms of electric and magnetic fields and also in terms of plasma velocities. The fields and velocities are then connected through the space-charge densities self-consistently. We solve the pulsar equation analytically for the fields and construct the standard steady-state pulsar magnetosphere. By considering the unipolar induction inside the pulsar and the magnetosphere outside the pulsar as one coupled system, and under the condition that the unipolar pumping rate exceeds the Poynting flux in the open field lines, plasma pressure can build up in the magnetosphere, in particular, in the closed region. This could cause a periodic opening up of the closed region, leading to a pulsating magnetosphere, which could be an alternative to pulsar beacons. The closed region can also be opened periodically by the build up of toroidal magnetic field through a positive feedback cycle.

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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 transport wild mammals or birds to the United States shall be designed, constructed, and maintained so as to.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  10. 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 transport wild mammals or birds to the United States shall be designed, constructed, and maintained so as to.... (c) No wild mammal or bird shall be placed in a cargo space of a conveyance that does not...

  11. 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...

  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. 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.

  14. 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.

  15. 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)

  16. 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.

  17. Integrating Beneficiation into Regolith Conveyance Systems

    NASA Technical Reports Server (NTRS)

    Metzger, Philip T.; Mantovani, James H.; Townsend, I. I.; Mueller, Robert P.

    2010-01-01

    Regolith conveyance includes hauler/dumpers, hoppers, augers, pneumatic transport subsystems, and other elements. The features of the conveyance and the time the material stream spend in conveyance may be used synergistically to perform beneficiation, pre-processing (such as heating), and other tasks, thus reducing the mass and complexity of the overall ISRU system. Since the cost of spaceflight is largely driven by the cost of launching mass out of Earth's gravity well, the conveyance system should be leveraged in this way to the maximum extent.

  18. On-line automatic detection of wood pellets in pneumatically conveyed wood dust flow

    NASA Astrophysics Data System (ADS)

    Sun, Duo; Yan, Yong; Carter, Robert M.; Gao, Lingjun; Qian, Xiangchen; Lu, Gang

    2014-04-01

    This paper presents a piezoelectric transducer based system for on-line automatic detection of wood pellets in wood dust flow in pneumatic conveying pipelines. The piezoelectric transducer senses non-intrusively the collisions between wood pellets and the pipe wall. Wavelet-based denoising is adopted to eliminate environmental noise and recover the collision events. Then the wood pellets are identified by sliding a time window through the denoised signal with a suitable threshold. Experiments were carried out on a laboratory test rig and on an industrial pneumatic conveying pipeline to assess the effectiveness and operability of the system.

  19. Auroral pulsations from ionospheric winds

    SciTech Connect

    Nakada, M.P. )

    1989-11-01

    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 Pederson 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Dayside Pi 2 pulsations at low altitudes

    SciTech Connect

    Sutcliffe, P.R. ); Yumoto, Kiyohumi )

    1989-08-01

    In this paper the authors investigate the occurrence of dayside Pi 2 geomagnetic pulsations at low and mid latitudes. The technique of data adaptive filtering is used to identify Pi 2's concealed by the presence of typical daytime Pc type pulsations. Convincing new evidence is presented demonstrating that Pi 2 pulsations occur simultaneously in both the nightside and dayside hemispheres at low latitudes. Dayside Pi 2's are occasionally identified at mid latitudes. These results have implications with regard to the source mechanism for low latitude Pi 2 pulsations and allude to a global cavity mode.

  5. 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.

  6. 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.

  7. 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.

  8. Constant auroral forms during regular pulsations

    NASA Astrophysics Data System (ADS)

    Roldugin, V. K.; Roldugin, A. V.

    2016-01-01

    A case is described in which complex auroral forms varied slightly at Lovozero Observatory over the course of more than an hour in the morning hours during the auroral recovery phase. Pc3 and Pc5 auroral and geomagnetic pulsations were observed during the event. The phenomenon is compared with recurrent pulsating auroras, which are described in the literature.

  9. 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.

  10. Pi2 pulsations in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Lin, C. C.; Cahill, L. J., Jr.

    1975-01-01

    Several substorms were observed at Explorer 45 in November and December 1971, and January and February 1972, while the satellite was in the evening quadrant near L = 5. These same substorms were identified in ground level magnetograms from auroral zone and low latitude stations. The satellite vector magnetic field records and rapid run ground magnetograms were examined for evidence of simultaneous occurrence of Pi2 magnetic pulsations. Pulsations which began abruptly were observed at the satellite during 7 of the 13 substorms studied and the pulsations occurred near the estimated time of substorm onset. These 7 pulsation events were also observed on the ground and 6 were identified in station comments as Pi2. All of the events observed were principally compressional waves, that is, pulsations in field magnitude. There were also transverse components elliptically polarized counter-clockwise looking along the field line. Periods observed ranged from 40 to 200 sec with 80 sec often the dominant period.

  11. 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.

  12. 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

  13. Limestone calcination during pulsating combustion

    SciTech Connect

    James, R.E. III ); Richards, G.A. )

    1992-01-01

    METC is currently conducting research on enhanced calcination during pulsating combustion as part of the Heat Engines program. It has been shown elsewhere that rapid, high temperature calcination will result in a calcined product with relatively large surface area, as desired for sulfur capture. It is proposed that such a process may occur during pulsating combustion where the oscillating pressure/velocity field around a particle increases the heat/mass transfer to and from the particle. To test this hypothesis, calcination tests in progress at METC use a novel form of pulse combustion called thermal'' pulse combustion, operating at 60000 BTUH, 100 Hz, and 5--15 psig peak-to- peak amplitude. Two configurations are being studied during the testing: one configuration is injection of sorbent into a refractory lined drop tube being heated by the pulse combustor, and the other configuration is injection of the sorbent into the pulse combustor through its centerbody and along the tailpipe at various positions. To understand the observed behavior, a characterization study of the pulse combustor is being conducted. Different flow rates, equivalence ratios, and injection positions are being tested.

  14. Dynamic instability of ducts conveying fluid

    NASA Technical Reports Server (NTRS)

    Yu, Y. Y.

    1975-01-01

    A finite element analysis was used to study dynamic instability in ducts conveying high speed fluids. Ducts examined include cantilevered curved, flexibly supported, arbitrarily shaped, and composite duct systems. Partial differential equations were used to study the duct systems.

  15. Piping Analysis

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Burns & McDonnell provide architectural and engineering services in planning, design and construction of a wide range of projects all over the world. In design analysis, company regularly uses COSMIC computer programs. In computer testing piping design of a power plant, company uses Pipe Flexibility Analysis Program (MEL-21) to analyze stresses due to weight, temperature, and pressure found in proposed piping systems. Individual flow rates are put into the computer, then computer calculates the pressure drop existing across each component; if needed, design corrections or adjustments can be made and rechecked.

  16. Piping Flexibility

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A NASA computer program aids Hudson Engineering Corporation, Houston, Texas, in the design and construction of huge petrochemical processing plants like the one shown, which is located at Ju'aymah, Saudi Arabia. The pipes handling the flow of chemicals are subject to a variety of stresses, such as weight and variations in pressure and temperature. Hudson Engineering uses a COSMIC piping flexibility analysis computer program to analyze stresses and unsure the necessary strength and flexibility of the pipes. This program helps the company realize substantial savings in reduced engineering time.

  17. Persistent, widespread pulsating aurora: A case study

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    Observations of a pulsating aurora event occurring on 11 February 2008, using the Time History of Events and Macroscale Interactions during Substorms (THEMIS) All-Sky Imager (ASI) array, indicate a spatially and temporally continuous event with a duration of greater than 15 h and covering a region with a maximum size of greater than 10 h magnetic local time. The optical pulsations are at times locally interrupted or drowned out by auroral substorm activity but are observed in the same location once the discrete aurora recedes. The pulsations following the auroral breakup appear to be brighter and have a larger patch size than before breakup. This suggests that, while the onset of pulsating aurora is not necessarily dependent upon a substorm precursor, the pulsations are affected and possibly enhanced by the substorm process. The long duration of this pulsating aurora event, lasting approximately 8 h without interruption as imaged from Gillam station, is significantly longer than the typical 2-3 h substorm recovery phase, suggesting that pulsating aurora is not strictly a recovery phase phenomenon. This paper is accompanied by a movie of the THEMIS ASI array data, from 0000 to 1715 UT, plotted in mosaic and superimposed onto a map of North America.

  18. 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.

  19. Pulsations and outbursts of luminous blue variables

    SciTech Connect

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

    1997-06-01

    We propose an outburst mechanism for the most luminous stars in our and other galaxies. These million solar luminosity stars, with masses (after earlier mass loss) of between 20 and maybe 70 solar masses, are pulsationally unstable for both radial and low-degree nonradial modes. Some of these modes are ``strange,`` meaning mostly that the pulsations are concentrated near the stellar surface and have very rapid growth rates in linear theory. The pulsation driving is by both the high iron line opacity (near 150,000 K) and the helium opacity (near 30,000 K) kappa effects. Periods range from 5 to 40 days. Depending on the composition, pulsations periodically produce luminosities above the Eddington limit for deep layers. The radiative luminosity creates an outward push that readily eases the very low gamma envelope to very large outburst radii. A key point is that a super-Eddington luminosity cannot be taken up by the sluggish convection rapidly enough to prevent an outward acceleration of much of the envelope. As the helium abundance in the envelope stellar material increases by ordinary wind mass loss and the luminous blue variable outbursts, the opacity in the deep pulsation driving layers decreases. This makes the current Eddington luminosity even higher so that pulsations can then no longer give radiative luminosities exceeding the limit. For the lower mass and luminosity luminous blue variables there is considerably less iron line opacity driving, and pulsations are almost all caused by the helium ionization kappa effect.

  20. Pulsations in close binaries: challenges and opportunities

    NASA Astrophysics Data System (ADS)

    Maceroni, C.; Lehmann, H.; Da Silva, R.; Montalbán, J.

    2015-09-01

    CoRoT and Kepler provided a precious by-product: a number of eclipsing binaries containing variable stars and, among these, non-radial pulsators. This providential occurrence allows combining independent information from two different phenomena whose synergy yields scientific results well beyond those from the single sources. In particular, the analysis of pulsations in eclipsing binary components throws light on the internal structure of the pulsating star, on the system evolution, and on the role of tidal forces in exciting the oscillations. The case study of the Kepler target KIC 3858884 is illustrative of the difficulties of analysis and of the achievements in this rapidly developing field.

  1. 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.

  2. 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.

  3. 24 CFR 203.402 - Items included in payment-conveyed and non-conveyed properties.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Items included in payment-conveyed and non-conveyed properties. 203.402 Section 203.402 Housing and Urban Development Regulations... items: (a) Taxes, ground rents, water rates, and utility charges that are liens prior to the...

  4. 24 CFR 203.402 - Items included in payment-conveyed and non-conveyed properties.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Items included in payment-conveyed and non-conveyed properties. 203.402 Section 203.402 Housing and Urban Development Regulations... items: (a) Taxes, ground rents, water rates, and utility charges that are liens prior to the...

  5. 24 CFR 203.402 - Items included in payment-conveyed and non-conveyed properties.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Items included in payment-conveyed and non-conveyed properties. 203.402 Section 203.402 Housing and Urban Development Regulations... items: (a) Taxes, ground rents, water rates, and utility charges that are liens prior to the...

  6. Statistical study of dayside pulsating aurora

    NASA Astrophysics Data System (ADS)

    Kanmae, T.; Kadokura, A.; Ogawa, Y.; Ebihara, Y.; Motoba, T.; Gerrard, A. J.; Weatherwax, A. T.

    2015-12-01

    Pulsating aurora normally occurs after a substorm breakup in the midnight sector, often observed to persist through the morning sector and beyond. Indeed, it has also been observed on the dayside; however, the characteristics of the dayside pulsating aurora are poorly known. A handful of observational studies have been reported, but the results are somewhat disputable because most of the studies had non-uniform sampling of the dark dayside region. Furthermore, the previous studies used photometer data, with which the spatial characteristics of the pulsating aurora cannot be examined. To determine both temporal and spatial characteristics of the pulsating aurora, we have studied three years of all-sky image data obtained at the South Pole station. Because of its unique geographical location, the station has 24 hours of darkness during the austral winter from April to August, providing an ideal platform for studying dayside aurora. In a preliminary survey of the data, we have identified the pulsating auroras in 198 days out of 365 days of observations. The magnetic local time (MLT) distribution of the occurrence peaks between 9:00 and 11:00, but shows no or little dependence on the geomagnetic activity. In many events, pulsating patches initially appear as east-west aligned arc segments and later in the afternoon sector develop into large, diffuse patches, which occasionally fill a large part of the field of view. Using the long-term data, we will statistically examine both temporal (occurrence rate, duration and pulsation period) and spatial (sizes and shapes) characteristics of the dayside pulsating aurora.

  7. 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.

  8. 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.

  9. 27 CFR 19.477 - Use of bulk conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Use of bulk conveyances... § 19.477 Use of bulk conveyances. If a bulk conveyance meets the construction requirements of § 19.478 or is approved under § 19.473(b), a proprietor may use the bulk conveyance on bonded premises for...

  10. 43 CFR 2720.4 - Issuance of document of conveyance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) CONVEYANCE OF FEDERALLY-OWNED MINERAL INTERESTS Conveyance of Federally-Owned Mineral Interests § 2720.4 Issuance of document of conveyance. Upon... shall issue the necessary document conveying to the applicant the mineral interests of the United...

  11. 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.

  12. Radial pulsations in DB white dwarfs?

    NASA Technical Reports Server (NTRS)

    Kawaler, Steven D.

    1993-01-01

    Theoretical models of DB white dwarfs are unstable against radial pulsation at effective temperatures near 20,000-30,000 K. Many high-overtone modes are unstable, with periods ranging from 12 s down to the acoustic cutoff period of approximately 0.1 s. The blue edge for radial instability lies at slightly higher effective temperatures than for nonradial pulsations, with the temperature of the blue edge dependent on the assumed efficiency of convection. Models with increased convective efficiency have radial blue edges that are increasingly closer to the nonradial blue edge; in all models the instability persists into the nonradial instability strip. Radial pulsations therefore may exist in the hottest DB stars that lie below the DB gap; the greatest chance for detection would be observations in the ultraviolet. These models also explain why searches for radial pulsations in DA white dwarfs have failed: the efficient convection needed to explain the blue edge for nonradial DA pulsation means that the radial instability strip is 1000 K cooler than found in previous investigations. The multiperiodic nature of the expected pulsations can be used to advantage to identify very low amplitude modes using the uniform spacing of the modes in frequency. This frequency spacing is a direct indicator of the mass of the star.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Heat pipes to reduce engine exhaust emissions

    NASA Technical Reports Server (NTRS)

    Schultz, D. F. (Inventor)

    1984-01-01

    A fuel combustor is presented that consists of an elongated casing with an air inlet conduit portion at one end, and having an opposite exit end. An elongated heat pipe is mounted longitudinally in the casing and is offset from and extends alongside the combustion space. The heat pipe is in heat transmitting relationship with the air intake conduit for heating incoming air. A guide conduit structure is provided for conveying the heated air from the intake conduit into the combustion space. A fuel discharge nozzle is provided to inject fuel into the combustion space. A fuel conduit from a fuel supply source has a portion engaged in heat transfer relationship of the heat pipe for preheating the fuel. The downstream end of the heat pipe is in heat transfer relationship with the casing and is located adjacent to the downstream end of the combustion space. The offset position of the heat pipe relative to the combustion space minimizes the quenching effect of the heat pipe on the gaseous products of combustion, as well as reducing coking of the fuel on the heat pipe, thereby improving the efficiency of the combustor.

  18. 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.

  19. 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.

  20. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... maintained so as to prevent the harmful ingress of engine exhaust fumes and gases produced by the conveyance... sufficient air for it to breathe normally. Primary enclosures shall be positioned in a cargo space in such a manner that each animal has access to sufficient air for normal breathing. (d) The interior of an...

  1. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... maintained so as to prevent the harmful ingress of engine exhaust fumes and gases produced by the conveyance... sufficient air for it to breathe normally. Primary enclosures shall be positioned in a cargo space in such a manner that each animal has access to sufficient air for normal breathing. (d) The interior of an...

  2. 50 CFR 14.107 - Conveyance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... maintained so as to prevent the harmful ingress of engine exhaust fumes and gases produced by the conveyance... sufficient air for it to breathe normally. Primary enclosures shall be positioned in a cargo space in such a manner that each animal has access to sufficient air for normal breathing. (d) The interior of an...

  3. 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...

  4. 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...

  5. 33 CFR 211.80 - Conveyance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Conveyance. 211.80 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...

  6. 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...

  7. 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...

  8. New pulsating white dwarfs in cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Nilsson, R.; Uthas, H.; Ytre-Eide, M.; Solheim, J.-E.; Warner, B.

    2006-07-01

    The number of discovered non-radially pulsating white dwarfs (WDs) in cataclysmic variables (CVs) is increasing rapidly by the aid of the Sloan Digital Sky Survey (SDSS). We performed photometric observations of two additional objects, SDSS J133941.11+484727.5 (SDSS 1339), independently discovered as a pulsator by Gänsicke et al., and SDSS J151413.72+454911.9, which we identified as a CV/ZZ Ceti hybrid. In this Letter we present the results of the remote observations of these targets performed with the Nordic Optical Telescope (NOT) during the Nordic-Baltic Research School at Molėtai Observatory, and follow-up observations executed by NOT in service mode. We also present three candidates we found to be non-pulsating. The results of our observations show that the main pulsation frequencies agree with those found in previous CV/ZZ Ceti hybrids, but specifically for SDSS 1339 the principal period differs slightly between individual observations and also from the recent independent observation by Gänsicke et al. Analysis of SDSS colour data for the small sample of pulsating and non-pulsating CV/ZZ Ceti hybrids found so far seems to indicate that the r - i colour could be a good marker for the instability strip of this class of pulsating WDs. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. E-mail: ricky@astro.lu.se

  9. Thermal Management Using Pulsating Jet Cooling Technology

    NASA Astrophysics Data System (ADS)

    Alimohammadi, S.; Dinneen, P.; Persoons, T.; Murray, D. B.

    2014-07-01

    The existing methods of heat removal from compact electronic devises are known to be deficient as the evolving technology demands more power density and accordingly better cooling techniques. Impinging jets can be used as a satisfactory method for thermal management of electronic devices with limited space and volume. Pulsating flows can produce an additional enhancement in heat transfer rate compared to steady flows. This article is part of a comprehensive experimental and numerical study performed on pulsating jet cooling technology. The experimental approach explores heat transfer performance of a pulsating air jet impinging onto a flat surface for nozzle-to-surface distances 1 <= H/D <= 6, Reynolds numbers 1,300 <= Re <= 2,800 pulsation frequency 2Hz <= f <= 65Hz, and Strouhal number 0.0012 <= Sr = fD/Um <= 0.084. The time-resolved velocity at the nozzle exit is measured to quantify the turbulence intensity profile. The numerical methodology is firstly validated using the experimental local Nusselt number distribution for the steady jet with the same geometry and boundary conditions. For a time-averaged Reynolds number of 6,000, the heat transfer enhancement using the pulsating jet for 9Hz <= f <= 55Hz and 0.017 <= Sr <= 0.102 and 1 <= H/D <= 6 are calculated. For the same range of Sr number, the numerical and experimental methods show consistent results.

  10. 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)

  11. 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

  12. SuperDARN observations of pulsating aurora

    NASA Astrophysics Data System (ADS)

    Clausen, L. B. N.; Yeoman, T. K.; Hosokawa, K.; Yukimatu, A. S.; Sato, N.; Milan, S. E.; Lester, M.

    2009-04-01

    On 25 September 2006 the all-sky camera located in Tjornes, Iceland observed pulsating aurora. During the event, the SuperDARN radar at Pykkvibaer was running in a high time, high spatial resolution mode and observed oscillating Doppler velocities. The pulsating velocities were observed in two separate patches of backscatter at different range gates, with different velocities. Backscattered power and spectral width as well as elevation angle data suggest that the power associated with each patch travelled along different ray paths. We discuss possible ray paths as well as the mechanisms that could have led to the difference in Doppler velocity observed for each patch.

  13. Heat pipe technology

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A bibliography of heat pipe technology to provide a summary of research projects conducted on heat pipes is presented. The subjects duscussed are: (1) heat pipe applications, (2) heat pipe theory, (3) design and fabrication, (4) testing and operation, (5) subject and author index, and (6) heat pipe related patents.

  14. Ionospheric variation during pulsating aurora

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Ogawa, Y.

    2015-07-01

    We have statistically analyzed data from the European Incoherent Scatter (EISCAT) UHF/VHF radars in Tromsø (69.60°N, 19.20°E), Norway, to reveal how the occurrence of pulsating auroras (PsAs) modifies the electron density profile in the ionosphere. By checking five winter seasons' (2007-2012) observations of all-sky aurora cameras of the National Institute of Polar Research in Tromsø, we have extracted 21 cases of PsA. During these PsA events, either the UHF or VHF radar of EISCAT was operative and the electron density profiles were obtained along the field-aligned or vertical direction near the zenith. From these electron density measurements, we calculated hmE (E region peak height) and NmE (E region peak density), which are proxies for the energy and flux of the precipitating PsA electrons, respectively. Then, we examined how these two parameters changed during the evolution of 21 PsA events in a statistical fashion. The results can be summarized as follows: (1) hmE is lower (the energy of precipitation electrons is higher) during the periods of PsA than that in the surrounding interval; (2) when NmE is higher (flux of PsA electrons is larger), hmE tends to be lower (precipitation is harder); (3) hmE is lower and NmE is larger in the later magnetic local time; and (4) when the AE index during the preceding substorm is larger, hmE is lower and NmE is larger. These tendencies are discussed in terms of the characteristics of particles and plasma waves in the source of PsA in the magnetosphere. In addition to the statistics of the EISCAT data, we carried out several detailed case studies, in which the altitude profiles of the electron density were derived by separating the On and Off phases of PsA. This allows us to estimate the true altitude profiles of the PsA ionization, which can be used for estimating the characteristic energy of the PsA electrons and better understanding the wave-particle interaction process in the magnetosphere.

  15. A PNEUMATIC CONVEYING TEST RIG FOR MUNICIPAL SOLID WASTE FRACTIONS

    EPA Science Inventory

    This report analyzes the material properties and system parameters relevant to the pneumatic conveying of municipal solid waste and its processed fractions. Comparisons are made with the conveying of conventional industrial feedstocks, and a rationale for sizing and specification...

  16. 32 CFR 174.9 - Economic development conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Economic development conveyances. 174.9 Section... Economic development conveyances. (a) The Secretary concerned may transfer real property and personal... Development Conveyance (EDC). (b) For installations having a date of approval for closure after January...

  17. 32 CFR 174.9 - Economic development conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Economic development conveyances. 174.9 Section... Economic development conveyances. (a) The Secretary concerned may transfer real property and personal... Development Conveyance (EDC). (b) For installations having a date of approval for closure after January...

  18. 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....

  19. 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....

  20. 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...

  1. 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...

  2. 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 RECORDING OF AIRCRAFT TITLES AND SECURITY DOCUMENTS General § 49.21 Return of original conveyance. If a person submitting a conveyance for...

  3. 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....

  4. 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....

  5. 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....

  6. 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....

  7. 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....

  8. 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....

  9. 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....

  10. 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....

  11. 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... CONVEYANCE SANITATION Equipment and Operation of Land and Air Conveyances § 1250.51 Railroad...

  12. Evaluation of Pump Pulsation in Respirable Size-Selective Sampling: Part I. Pulsation Measurements

    PubMed Central

    Lee, Eun Gyung; Lee, Larry; Möhlmann, Carsten; Flemmer, Michael M.; Kashon, Michael; Harper, Martin

    2015-01-01

    Pulsations generated by personal sampling pumps modulate the airflow through the sampling trains, thereby varying sampling efficiencies, and possibly invalidating collection or monitoring. The purpose of this study was to characterize pulsations generated by personal sampling pumps relative to a nominal flow rate at the inlet of different respirable cyclones. Experiments were conducted using a factorial combination of 13 widely used sampling pumps (11 medium and 2 high volumetric flow rate pumps having a diaphragm mechanism) and 7 cyclones [10-mm nylon also known as Dorr-Oliver (DO), Higgins-Dewell (HD), GS-1, GS-3, Aluminum, GK2.69, and FSP-10]. A hot- wire anemometer probe cemented to the inlet of each cyclone type was used to obtain pulsation readings. The three medium flow rate pump models showing the highest, a midrange, and the lowest pulsations and two high flow rate pump models for each cyclone type were tested with dust-loaded filters (0.05, 0.21, and 1.25 mg) to determine the effects of filter loading on pulsations. The effects of different tubing materials and lengths on pulsations were also investigated. The fundamental frequency range was 22–110 Hz and the magnitude of pulsation as a proportion of the mean flow rate ranged from 4.4 to 73.1%. Most pump/cyclone combinations generated pulse magnitudes >10% (48 out of 59 combinations), while pulse shapes varied considerably. Pulsation magnitudes were not considerably different for the clean and dust-loaded filters for the DO, HD, and Aluminum cyclones, but no consistent pattern was observed for the other cyclone types. Tubing material had less effect on pulsations than tubing length; when the tubing length was 183 cm, pronounced damping was observed for a pump with high pulsation (>60%) for all tested tubing materials except for the Tygon Inert tubing. The findings in this study prompted a further study to determine the possibility of shifts in cyclone sampling efficiency due to sampling pump pulsations

  13. 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.

  14. Pulsations in total columnar electron content

    NASA Technical Reports Server (NTRS)

    Okuzawa, T.; Davies, K.

    1981-01-01

    Radio signals from the ATS 6 beacon received at Boulder reveal small-amplitude, quasi-sinusoidal fluctuations with periods in the range of 10 to 50 s. Visual comparisons of these data (116 events for October 1974 to April 1975) shows a good correspondence with simultaneous geomagnetic pulsations at Boulder in two thirds of the cases for which Boulder magnetograms were available, but they do not necessarily correspond with magnetic pulsations on ATS 6. Spectral analyses, by the method of maximum entropy, were made on sample records. The principal results are the following: (1) The occurrence of the pulsations is higher on magnetically disturbed days. (2) The maximum likelihood of occurrence is around 2100 UT (1400 LT). (3) The dominant spectrum peaks of the radio fluctuations and geomagnetic field on the ground generally coincide. Cases are found also in which temporal characteristics of the spectra are similar. These results indicate a close association of the radio fluctuations with the Pc 3-4 type pulsations of the geomagnetic field on the ground. It is suggested that the radio fluctuations originate mainly in the F region of the ionosphere, while some of them could be due to plasmapause effects.

  15. 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…

  16. 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.

  17. On the standing wave mode of giant pulsations

    NASA Technical Reports Server (NTRS)

    Takahashi, K.; Sato, N.; Warnecke, J.; Luehr, H.; Spence, H. E.; Tonegawa, Y.

    1992-01-01

    In order to determine the standing wave mode of giant pulsations, a systematic survey of magnetic field data from the AMPTE CCE spacecraft and from ground stations located near the geomagnetic foot point of CCE was made. One giant pulsation was associated with a compressional wave, while no giant pulsation was observed in association with transverse wave events. The CCE magnetic field record for the giant pulsation exhibited a remarkable similarity to a giant pulsation observed from the ATS 6 geostationary satellite near the magnetic equator. It is concluded that the compressional nature of the giant pulsation is due to an odd-mode standing wave structure, which places a strong constraint on the generation mechanism of giant pulsations.

  18. 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.

  19. 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.

  20. 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. PMID:24146920

  1. 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.

  2. Ultrasonic pipe assessment

    SciTech Connect

    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.

  3. Shield For Flexible Pipe

    NASA Technical Reports Server (NTRS)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  4. Short cracks in piping and piping welds

    SciTech Connect

    Wilkowski, G.M.; Brust, F.; Francini, R.; Ghadiali, N.; Kilinski, T.; Krishnaswamy, P.; Landow, M.; Marschall, C.W.; Rahman, S.; Scott, P. )

    1992-04-01

    This is the second semiannual report of the US Nuclear Regulatory Commission's Short Cracks in Piping and Piping Welds research program. The program began in March 1990 and will extend for 4 years. The intent of this program is to verify and improve fracture analyses for circumferentially cracked large-diameter nuclear piping with crack sizes typically used in leak-before-break analyses or in-service flaw evaluations. Only quasi-static loading rates are evaluated since the NRC's International Piping Integrity Research Group (IPIRG) program is evaluating the effects of seismic loading rates on cracked piping systems. Progress for through-wall-cracked pipe involved (1) conducting a 28-inch diameter stainless steel SAW and 4-inch diameter French TP316 experiments, (2) conducting a matrix of FEM analyses to determine GE/EPRI functions for short TWC pipe, (3) comparison of uncracked pipe maximum moments to various analyses and FEM solutions, (4) development of a J-estimation scheme that includes the strength of both the weld and base metals. Progress for surface-cracked pipe involved (1) conducting two experiments on 6-inch diameter pipe with d/t = 0.5 and {Theta}/{pi} = 0.25 cracks, (2) comparisons of the pipe experiments to Net-Section-Collapse predictions, and (3) modification of the SC.TNP and SC.TKP J-estimation schemes to include external surface cracks.

  5. 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.

  6. Pulsation and mass loss in Mira variables

    NASA Technical Reports Server (NTRS)

    Wood, P. R.

    1980-01-01

    The behavior of pulsation in the outer layers of a typical Mira variable was studied in the adiabatic and isothermal limits. A shock wave propagates outward once per period and the radial velocity obtained from observations of hydrogen emission lines is identified with the velocity of gas in the post shock region. In the adiabatic case, mass loss in the form of a steady stellar wind was produced. In the isothermal case, no continuous mass loss was produced but occasional ejection of shells occur. Pulsation introduced into a star undergoing steady mass loss as a result of radiation pressure acting on grains caused the mass loss rate to increase by a factor of approximately 40, while the terminal velocity of the flow was almost unaltered.

  7. The eight-schwabe-cycle pulsation

    NASA Astrophysics Data System (ADS)

    Richard, Jean-Guillaume

    2004-09-01

    The shape of the Sun’s secular activity cycle is found to be a saw-tooth curve. The additional Schwabe cycle 4‧ (1793 1799) suggested by Usoskin, Mursula, and Kovaltsov (2001a) is taken into account in the telescopic sunspot record (1610 2001). Instead of a symmetrical Gleissberg cycle, a saw-tooth of exactly eight Schwabe sunspot maxima (‘Pulsation’) is found. On average, the last sunspot maximum of an eight-Schwabe-cycle saw-tooth pulsation has been about three times as high as its first maximum. The Maunder Minimum remains an exception to this pattern. The Pulsation is defined as a secular-scale envelope of Schwabe-cycle maxima, whereas the Gleissberg cycle is a result of long-term smoothing of the sunspot series.

  8. A new driving mechanism for stellar pulsations

    NASA Astrophysics Data System (ADS)

    Pesnell, W. Dean

    1987-03-01

    A new driving mechanism termed "convective blocking", a variation of the normal κ- and γ-mechanisms in Cepheids, is demonstrated using two models of hydrogen white dwarf stars. This mechanism is shown to be physically reasonable in the limit of frozen convection (implying the time scale for convective readjustment is long compared to a pulsation period). Some qualitative effects are given for when the two time scales are not as disparate.

  9. Pulsating aurorae: Evidence for flux limiting

    SciTech Connect

    Davidson, G.T.; Sears, R.D.

    1980-03-01

    Theoretical models based upon the concept of self-modulated VLF wave-electron interactions have been proposed to explain pulsating aurorae. These models incorporate the idea of a trapping limit, above which strong diffusion into the loss cone rapidly removes any excess electrons. At flux values near the trapping limit, perturbations of the trapped electron distribution can result in cyclic wave growth and electron precipitation. The trapping limit is thus related to the energy deposited and the characteristic energy of electrons precipitated in pulsating aurorae. Photometric measurements of the total energy deposit and of the mean energy parameter made at Chatanika, Alaska (invariant geomagnetic latitude, 65 /sup 0/) indicate that the well-developed pulsations are caused mainly by a modulation of the mean energy parameter. Thus, a nearly constant ''limiting'' value for the precipitating flux is measured F=7 x 10/sup 8/ el/cm/sup 2/ sec from which a trapped flux limit of Japprox. =3 x 10/sup 9/ el/cm/sup 2/ sec can be inferred.

  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. Simultaneous observation of monochromatic and variable period geomagnetic pulsations

    SciTech Connect

    McDiarmid, D.R.; Nielsen, E. )

    1987-05-01

    On February 4, 1983, following a storm sudden commencement, a monochromatic and a variable period pulsation were simultaneously observed by the Scandinavian Twin Auroral Radar Experiment (STARE) and Sweden and Britain Radar Experiment (SABRE) radar systems. Both pulsations differed from previously analyzed examples of their class. The phase of the monochromatic pulsation increased linearly with latitude rather than decreased. Its amplitude remained relatively constant over the latitude interval of linear phase change. The variable period pulsation experienced a change of orientation of its essentially linear polarization diagram in association with a discontinuity of its period. The variable period pulsation was thus manifest in both the toroidal and poloidal components. The results are discussed in terms of recent developments in theoretical pulsation modeling.

  12. 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.

  13. The δ Scuti Pulsation Periods in KIC 5197256

    NASA Astrophysics Data System (ADS)

    Turner, G.; Holaday, J.

    2015-06-01

    In this paper we present the pulsational spectrum for KIC 5197256. This object is an eclipsing binary system with a period of 6.96 days. We demonstrate that the light curve shows presence of δ Scuti pulsations with a dominant period of 0.1015 day. The object should therefore be included in the ever-growing class of eclipsing binary systems with at least one pulsating component.

  14. Detection and characterization of geomagnetic pulsations using HF ionospheric heating

    SciTech Connect

    Lee, H.S.; Ferraro, A.J.; Olson, J.V. Alaska Univ., Fairbanks )

    1990-12-01

    This paper describes the geomagnetic pulsations observed in the high-latitude ionosphere during an experiment dealing with the ionospheric generation of ELF/VLF EM waves in June and October 1987. There was clear evidence of geomagnetic pulsations intermixed with the ELF/VLF signals in both the magnitude and phase data. A simple simulation model is introduced to facilitate the interpretation of the data, and a procedure for characterizing the pulsation is described. 5 refs.

  15. Helium abundance effects on RR Lyrae pulsation properties

    NASA Astrophysics Data System (ADS)

    Marconi, M.; Coppola, G.; Bono, G.; Braga, V.; Pietrinferni, A.

    2016-05-01

    A new set of nonlinear convective pulsation models of RR Lyrae stars has been computed varying both the metallicity and the helium content. To constrain the helium dependence of pulsation observables we adopted, for each metal content, at least three different helium abundances. We provide for the first time a homogeneous evolutionary and pulsation framework covering the entire range of cluster and field variables. The implications for the use of RR Lyrae as stellar population tracers and distance indicators are briefly discussed.

  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. Periodic stellar pulsations - Stability analysis and amplitude equations

    NASA Astrophysics Data System (ADS)

    Buchler, J. R.; Moskalik, Pawel; Kovacs, Geza

    1991-10-01

    The stability properties of nonlinear periodic stellar pulsations are studied within the amplitude equation formalism. Both nonresonant and resonant pulsations are considered. A comparison to a sequence of classical Cepheid models shows that the formalism provides a good qualitative and quantitative description of the behavior of the Floquet coefficients and that it also captures the most important features of the Floquet eigenvectors. It thus helps shed new light on the behavior (bifurcations) of pulsating stars. In addition, the predictive powers of the analytical approach allow a systematic search for models with specific pulsational properties.

  18. Magnetic pulsations at the quasi-parallel shock

    NASA Technical Reports Server (NTRS)

    Thomsen, M. F.; Gosling, J. T.; Bame, S. J.; Russell, C. T.

    1990-01-01

    The plasma and field properties of large-amplitude magnetic field pulsatins upstream from the quasi-parallel region of the earth's bow shock are examined in high time resolution using data from ISEE 1 and 2. The relative timing of the magnetic field profiles observed at the two spacecraft shows that some of the pulsations are convecting antisunward across the spacecraft while others are brief out/in motions of bow shock across the spacecraft. Pulsations with both timing signatures are the site of slowing and heating of the solar wind plasma. The ions tend to be only weakly heated in the convecting pulsations, while within the out/in pulsations the ion heating can be quite substantial but variable. This variation occurs not only from pulsation to pulsation but also from point to point within a given pulsation. In general, the hottest distributions within the out/in pulsations tend to occur in regions of lower density and field strength. Magnetic pulsations bear a number of similarities to previously identified hot diamagnetic cavity events as well as to more durable crossings of the quasi-parallel shock itself. These various phenomena may be different manifestations of the same basic physical processes, in particular the coupling of coherently reflected ions to the solar wind beam.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Identification of pulsational modes in rotating slowly pulsating B-type stars

    NASA Astrophysics Data System (ADS)

    Szewczuk, W.; Daszyńska-Daszkiewicz, J.

    2015-06-01

    Knowledge of the geometry of pulsational modes is a prerequisite for seismic modelling of stars. In the case of slowly pulsating B-type (SPB) pulsators, the simple zero-rotation approach so far used for mode identification is usually not valid because pulsational frequencies are often of the order of the rotational frequency. Moreover, this approach allows us to determine only the spherical harmonic degree, ℓ, while the azimuthal order, m, is beyond its reach. On the other hand, because of the density of oscillation spectra of SPB stars, knowledge of m is indispensable if one wants to assign the radial order, n, to the observed frequency peaks. Including the effects of rotation via the traditional approximation, we perform identification of the mode angular numbers (ℓ, m) for 31 SPB stars with available multicolour time series photometry. Simultaneously, constraints on the rotational velocity, Vrot, and the inclination angle, i, are determined assuming uniform rotation and a constant value of Vrot sin i. Dependence of the results on the adopted model is tested using HD 21071 as an example. Despite some model uncertainties and limitations of the method, our studies show the correct approach to identifying the low-frequency oscillation modes.

  4. 27 CFR 19.495 - Marks on bulk conveyances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Marks on bulk conveyances..., DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Containers and Marks Marking Requirements for Spirits § 19.495 Marks on bulk conveyances. (a) A proprietor must securely attach a label identifying...

  5. 27 CFR 19.495 - Marks on bulk conveyances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Marks on bulk conveyances..., DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Containers and Marks Marking Requirements for Spirits § 19.495 Marks on bulk conveyances. (a) A proprietor must securely attach a label identifying...

  6. 27 CFR 19.495 - Marks on bulk conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Marks on bulk conveyances..., DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Containers and Marks Marking Requirements for Spirits § 19.495 Marks on bulk conveyances. (a) A proprietor must securely attach a label identifying...

  7. 27 CFR 19.495 - Marks on bulk conveyances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Marks on bulk conveyances..., DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Containers and Marks Marking Requirements for Spirits § 19.495 Marks on bulk conveyances. (a) A proprietor must securely attach a label identifying...

  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... treatment of water upon investigations made by representatives of State departments of health or of...

  9. 21 CFR 1240.90 - Approval of treatment aboard conveyances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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... treatment of water upon investigations made by representatives of State departments of health or of...

  10. 21 CFR 1240.90 - Approval of treatment aboard conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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... treatment of water upon investigations made by representatives of State departments of health or of...

  11. 21 CFR 1240.90 - Approval of treatment aboard conveyances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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... treatment of water upon investigations made by representatives of State departments of health or of...

  12. 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...

  13. 43 CFR 2631.3 - Surveying and conveyance fees.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Surveying and conveyance fees. 2631.3... by Railroad Carriers (Transportation Act of 1940) § 2631.3 Surveying and conveyance fees. The carrier must pay the cost of the survey of the land, paying also one-half the cost of any segregation survey...

  14. 43 CFR 2631.3 - Surveying and conveyance fees.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Surveying and conveyance fees. 2631.3... by Railroad Carriers (Transportation Act of 1940) § 2631.3 Surveying and conveyance fees. The carrier must pay the cost of the survey of the land, paying also one-half the cost of any segregation survey...

  15. 43 CFR 2631.3 - Surveying and conveyance fees.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Surveying and conveyance fees. 2631.3... by Railroad Carriers (Transportation Act of 1940) § 2631.3 Surveying and conveyance fees. The carrier must pay the cost of the survey of the land, paying also one-half the cost of any segregation survey...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Automobiles or other....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility for financial assistance in the purchase of one automobile or other conveyance in an amount not exceeding...

  19. 38 CFR 3.808 - Automobiles or other conveyances; certification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Automobiles or other....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility for financial assistance in the purchase of one automobile or other conveyance in an amount not exceeding...

  20. 38 CFR 3.808 - Automobiles or other conveyances; certification.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Automobiles or other....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility for financial assistance in the purchase of one automobile or other conveyance in an amount not exceeding...

  1. 38 CFR 3.808 - Automobiles or other conveyances; certification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Automobiles or other....808 Automobiles or other conveyances; certification. (a) Entitlement. A certificate of eligibility for financial assistance in the purchase of one automobile or other conveyance in an amount not exceeding...

  2. 7 CFR 766.354 - Voluntary conveyance of chattel.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... subpart B of 7 CFR part 1956 before or in conjunction with the voluntary conveyance offer if the value of... borrower's account for all recoverable costs incurred in connection with the conveyance. (2) The Agency will credit the borrower's account in the amount of the market value of the chattel....

  3. 43 CFR 2641.4 - Approval of conveyance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Approval of conveyance. 2641.4 Section 2641.4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) FAA AIRPORT GRANTS Procedures § 2641.4 Approval of conveyance. (a) Each...

  4. 18 CFR 141.15 - Annual Conveyance Report.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... hydropower project is required by its license to file with the Commission an annual report of conveyances of... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Annual Conveyance Report. 141.15 Section 141.15 Conservation of Power and Water Resources FEDERAL ENERGY...

  5. 18 CFR 141.15 - Annual Conveyance Report.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... hydropower project is required by its license to file with the Commission an annual report of conveyances of... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Annual Conveyance Report. 141.15 Section 141.15 Conservation of Power and Water Resources FEDERAL ENERGY...

  6. 18 CFR 141.15 - Annual Conveyance Report.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... hydropower project is required by its license to file with the Commission an annual report of conveyances of... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Annual Conveyance Report. 141.15 Section 141.15 Conservation of Power and Water Resources FEDERAL ENERGY...

  7. 18 CFR 141.15 - Annual Conveyance Report.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... hydropower project is required by its license to file with the Commission an annual report of conveyances of... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Annual Conveyance Report. 141.15 Section 141.15 Conservation of Power and Water Resources FEDERAL ENERGY...

  8. 7 CFR 766.354 - Voluntary conveyance of chattel.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and equipment, as applicable; (5) A resolution approved by the governing body that authorizes the conveyance in the case of an entity borrower; (6) Complete debt settlement application in accordance with subpart B of 7 CFR part 1956 before or in conjunction with the voluntary conveyance offer if the value...

  9. 32 CFR 174.10 - Consideration for economic development conveyances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Consideration for economic development... Property § 174.10 Consideration for economic development conveyances. (a) For conveyances made pursuant to... the date of the initial transfer of property shall be used to support economic redevelopment of,...

  10. 32 CFR 174.10 - Consideration for economic development conveyances.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Consideration for economic development... Property § 174.10 Consideration for economic development conveyances. (a) For conveyances made pursuant to... the date of the initial transfer of property shall be used to support economic redevelopment of,...