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Sample records for kinetic ballooning modes

  1. Kinetic analysis of MHD ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    Tang, W.M.; Rewoldt, G.; Cheng, C.Z.; Chance, M.S.

    1984-10-01

    A comprehensive analysis of the stability properties of the appropriate kinetically generalized form of MHD ballooning modes together with the usual trapped-particle drift modes is presented. The calculations are fully electromagnetic and include the complete dynamics associated with compressional ion acoustic waves. Trapped-particle effects along with all forms of collisionless dissipation are taken into account without approximations. The influence of collisions is estimated with a model Krook operator. Results from the application of this analysis to realistic tokamak operating conditions indicate that unstable short-wavelength modes with significant growth rates can extend from β = 0 to value above the upper ideal-MHD-critical-beta associated with the so-called second stability regime. Since the strength of the relevant modes appears to vary gradually with β, these results support a soft beta limit picture involving a continuous (rather than abrupt or hard) modification of anomalous transport already present in low-β-tokamaks. However, at higher beta the increasing dominance of the electromagnetic component of the perturbations indicated by these calculations could also imply significantly different transport scaling properties

  2. Compressibility effects on ideal and kinetic ballooning modes and elimination of finite Larmor radius stabilization

    International Nuclear Information System (INIS)

    Kotschenreuther, M.

    1985-07-01

    The dynamics of ideal and kinetic ballooning modes are considered analytically including parallel ion dynamics, but without electron dissipation. For ideal modes, parallel dynamics predominantly determine the growth rate when β is within approx.30% of the ideal threshold, resulting in a substantial reduction in growth rate. Compressibility also eliminates the stabilization effects of finite Larmor radius (FLR); FLR effects (when temperature gradients are neglected) can even increase the growth rate above the MHD value. Temperature gradients accentuate this by adding a new source of free energy independent of the MHD drive, in this region of ballooning coordinate corresponding in MHD to the continuum. Analytic dispersion relations are derived demonstrating the effects above; the formalism emphasizes the similarities between the ideal MHD and kinetic cases

  3. Benchmark studies of the gyro-Landau-fluid code and gyro-kinetic codes on kinetic ballooning modes

    Energy Technology Data Exchange (ETDEWEB)

    Tang, T. F. [Dalian University of Technology, Dalian 116024 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Ma, C. H. [Fusion Simulation Center, School of Physics, Peking University, Beijing (China); Bass, E. M.; Candy, J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Holland, C. [University of California San Diego, La Jolla, California 92093-0429 (United States)

    2016-03-15

    A Gyro-Landau-Fluid (GLF) 3 + 1 model has been recently implemented in BOUT++ framework, which contains full Finite-Larmor-Radius effects, Landau damping, and toroidal resonance [Ma et al., Phys. Plasmas 22, 055903 (2015)]. A linear global beta scan has been conducted using the JET-like circular equilibria (cbm18 series), showing that the unstable modes are kinetic ballooning modes (KBMs). In this work, we use the GYRO code, which is a gyrokinetic continuum code widely used for simulation of the plasma microturbulence, to benchmark with GLF 3 + 1 code on KBMs. To verify our code on the KBM case, we first perform the beta scan based on “Cyclone base case parameter set.” We find that the growth rate is almost the same for two codes, and the KBM mode is further destabilized as beta increases. For JET-like global circular equilibria, as the modes localize in peak pressure gradient region, a linear local beta scan using the same set of equilibria has been performed at this position for comparison. With the drift kinetic electron module in the GYRO code by including small electron-electron collision to damp electron modes, GYRO generated mode structures and parity suggest that they are kinetic ballooning modes, and the growth rate is comparable to the GLF results. However, a radial scan of the pedestal for a particular set of cbm18 equilibria, using GYRO code, shows different trends for the low-n and high-n modes. The low-n modes show that the linear growth rate peaks at peak pressure gradient position as GLF results. However, for high-n modes, the growth rate of the most unstable mode shifts outward to the bottom of pedestal and the real frequency of what was originally the KBMs in ion diamagnetic drift direction steadily approaches and crosses over to the electron diamagnetic drift direction.

  4. A unified theory of resonant excitation of kinetic ballooning modes by energetic ions/alpha particles in tokamaks

    International Nuclear Information System (INIS)

    Biglari, H.; Chen, L.

    1991-10-01

    A complete theory of wave-particle interactions is presented whereby both circulating and trapped energetic ions can destabilize kinetic ballooning modes in tokamaks. Four qualitatively different types of resonances, involving wave-precessional drift, wave-transit, wave-bounce, and precessional drift-bounce interactions, are identified, and the destabilization potential of each is assessed. For a characteristic slowing-down distribution function, the dominant interaction is that which taps those resonant ions with the highest energy. Implications of the theory for present and future generation fusion experiments are discussed. 16 refs

  5. Unified theory of ballooning instabilities and temperature gradient driven trapped ion modes

    International Nuclear Information System (INIS)

    Xu, X.Q.

    1990-08-01

    A unified theory of temperature gradient driven trapped ion modes and ballooning instabilities is developed using kinetic theory in banana regimes. All known results, such as electrostatic and purely magnetic trapped particle modes and ideal MHD ballooning modes (or shear Alfven waves) are readily derived from our single general dispersion relation. Several new results from ion-ion collision and trapped particle modification of ballooning modes are derived and discussed and the interrelationship between those modes is established. 24 refs

  6. Ballooning modes or Fourier modes in a toroidal plasma?

    International Nuclear Information System (INIS)

    Connor, J.W.; Taylor, J.B.

    1987-01-01

    The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure

  7. Analysis of current diffusive ballooning mode

    International Nuclear Information System (INIS)

    Yagi, M.; Azumi, M.; Itoh, K.; Itoh, S.; Fukuyama, A.

    1993-04-01

    The current diffusive ballooning mode is analysed in the tokamak plasma. This mode is destabilized by the current diffusivity (i.e., the electron viscosity) and stabilized by the thermal conductivity and ion viscosity. By use of the ballooning transformation, the eigenmode equation is solved. Analytic solution is obtained by the strong ballooning limit. Numerical calculation is also performed to confirm the analytic theory. The growth rate of the mode and the mode structure are analysed. The stability boundary is derived in terms of the current diffusivity, thermal conductivity, ion viscosity and the pressure gradient for the given shear parameter. This result is applied to express the thermal conductivity in terms of the pressure gradient, magnetic configurational parameters (such as the safety factor, shear and aspect ratio) and the Prandtl numbers. (author)

  8. Viscoresistive g-modes and ballooning

    International Nuclear Information System (INIS)

    Dagazian, R.Y.; Paris, R.B.

    1980-01-01

    The resistive G-mode and its particular form, the resistive ballooning mode, are treated as limits of a single simple model. MHD theory including parallel and perpendicular viscosity, finite shear, and finite beta is employed to study their linear stability

  9. Ballooning mode stabilization by moderate sheared rotation

    International Nuclear Information System (INIS)

    Hameiri, E.

    1996-01-01

    Sheared toroidal plasma rotation has been known for some time to have a stabilizing effect on the ballooning modes. A recent calculation showed that a large flow shear, with dΩ/dq of the order of the Alfven toroidal frequency, can stabilize the ballooning modes. This latest result is, in fact, not so optimistic. For observed flows with Mach number of order unity one gets dΩ/dq smaller by a factor O(√β) from the required level (if the flow shear length is of the same order as the magnetic shear length). Moreover, the calculation does not take into account a possibly large transient growth of the mode amplitude due to its Floquet structures We show here that, in fact, there is a general tendency of the ballooning mode to stabilize as soon as the flow shear dΩ/dq exceeds the (O√β smaller) open-quotes slowclose quotes magnetosonic wave frequency. Our analysis is perturbative, where the small parameter is related to the small coupling between the slow and Alfven waves-as is the case in a high aspect-ratio tokamak. (In the perturbation it is important to take the Hamiltonian nature of the governing equations into account.) Moreover, our results apply to the relevant transient growth of the mode amplitude

  10. MHD simulation of high wavenumber ballooning-like modes in LHD

    International Nuclear Information System (INIS)

    Miura, H.; Nakajima, N.

    2008-10-01

    Dynamical growths of high-wavenumber ballooning modes are studied through full-3D nonlinear MHD simulations of the Large Helical Device. The growths of the ballooning modes are identified by studying the growth rates and the radial profiles of the Fourier coefficients of fluctuation variables. The mechanisms to weaken the growth of instability, such as the local fattening of the pressure and the energy release to the parallel kinetic energy, are found being insufficient to suppress the high-wavenumber ballooning modes. Consequently, the mean pressure profile is totally modified when the evolutions of the ballooning modes are saturated. The numerical results reveal that we need some mechanisms which do not originate from an ideal MHD to achieve a mild, saturated behaviors beyond the growths of unstable high ballooning modes in the helical device. The parallel heat conductivity is proposed as one of possible non-ideal mechanisms. (author)

  11. Properties of ballooning modes in the Heliotron configurations

    International Nuclear Information System (INIS)

    Nakajima, N.; Hudson, S.R.; Hegna, C.C.

    2005-01-01

    The stability of ballooning modes is influenced by the local and global magnetic shear and local and global magnetic curvature so significantly that it is fairly difficult to get those general properties in the three dimensional configurations with strong flexibility due to the external coil system. In the case of the planar axis heliotron configurations allowing a large Shafranov shift, like LHD, properties of the high-mode-number ballooning modes have been intensively investigated. It has been analytically shown that the local magnetic shear comes to disappear in the stellarator-like global magnetic shear region, as the Shafranov shift becomes large. Based on this mechanism and the characteristics of the local and global magnetic curvature, it is numerically shown that the destabilized ballooning modes have strong three-dimensional properties (both poloidal and toroidal mode couplings) in the Mercier stable region, and that those are fairly similar to ballooning modes in the axisymmetric system in the Mercier unstable region. As is well known, however, no quantization condition is applicable to the ballooning modes in the three-dimensional system without symmetry, and so the results of the high-mode-number ballooning modes in the covering space had to be confirmed in the real space. Such a confirmation has been done in the Mercier stable region and also in the Mercier unstable region by using three dimensional linearized ideal MHD stability code cas3d. Confirming the relation between high-mode-number ballooning analyses by the global mode analyses, the method of the equilibrium profile variations has been developed in the tree dimensional system, giving dt/dψ - dP/dψ stability diagram corresponding to the s - α diagram in tokamaks. This method of profile variation are very powerful to investigate the second stability of high-mode-number ballooning modes and has been more developed. Recently it has been applied to the plasma in the inward-shifted LHD

  12. Finite Larmor radius stabilization of ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    Tsang, K.T.

    1980-07-01

    A ballooning mode equation that includes full finite Larmor radius effects has been derived from the Vlasov equation for a circular tokamak equilibrium. Numerical solution of this equation shows that finite Larmor radius effects are stabilizing

  13. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.L.; Hassam, A.B.; Waltz, R.E.

    1995-01-01

    Stabilization of magnetohydrodynamic ballooning modes by sheared toroidal rotation is demonstrated using a shifted circle equilibrium model. A generalized ballooning mode representation is used to eliminate the fast Alfven wave, and an initial value code solves the resulting equations. The s-α diagram (magnetic shear versus pressure gradient) of ballooning mode theory is extended to include rotational shear. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq, where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and direct stable access to the second stability regime occurs when this frequency is approximately one-quarter to one-half the Alfven frequency, ω A =V A /qR. copyright 1995 American Institute of Physics

  14. Analysis of current diffusive ballooning mode in tokamaks

    International Nuclear Information System (INIS)

    Uchida, M.; Fukuyama, A.; Itoh, S.-I.; Yagi, M.

    1999-12-01

    The effect of finite gyroradius on the current diffusive ballooning mode is examined. Starting from the reduced MHD equations including turbulent transports, coupling with drift motion and finite gyroradius effect of ions, we derive a ballooning mode equation with complex transport coefficients. The eigenfrequency, saturation level and thermal diffusivity are evaluated numerically from the marginal stability condition. Preliminary results of their parameter dependence is presented. (author)

  15. Ballooning stability analysis of JET H-mode discharges

    International Nuclear Information System (INIS)

    O'Brien, D.P.; Galvao, R.; Keilhacker, M.; Lazzaro, E.; Watkins, M.L.

    1989-01-01

    Previous studies of the stability of a large aspect ratio model equilibrium to ideal MHD ballooning modes have shown that across the bulk of the plasma there exist two marginally stable values of the pressure gradient parameter α. These define an unstable zone which separates the first (small α) stable region from the second (large α) stable region. Close to the separatrix, however, the first and second regions can coalesce when the surface averaged current density, Λ, exceeds a critical value. The plasma in this region is then stable to ballooning modes at all values of the pressure gradient. In this paper we extend these results to JET H-mode equilibria using a finite aspect ratio ballooning formalism, and assess the relevance of ideal ballooning stability in these discharges. In particular we analyse shot 15894 at time 56 sec. which is 1.3 s into the H-phase. (author) 4 refs., 4 figs

  16. High n ballooning modes in highly elongated tokamaks

    International Nuclear Information System (INIS)

    An, C.H.; Bateman, G.

    1980-02-01

    An analytic study of stability against high n ballooning modes in highly elongated axisymmetric plasmas is presented and compared with computational results. From the equation for the marginal pressure gradient, it is found that the local shear plays an important role on the stability of elongated and shifted plasma, and that high elongation deteriorates the stability by decreasing the stabilizing effects of field line bending and local shear. The net contribution of the local shear to stability decreases with elongation and shift for strongly ballooning modes (eigenfunctions strongly localized near the outer edge of the toroidal flux surfaces) but increases for interchange modes (eigenfunctions more uniform along the flux surfaces). The computational study of high n ballooning modes in a highly elongated plasma reveals that lowering the aspect ratio and broadening the pressure profile enhance the marginal beta for β/sub p/ less than unity but severely reduce the marginal beta for β/sub p/ larger than unity

  17. Ballooning modes on open magnetic field lines

    International Nuclear Information System (INIS)

    Hameiri, E.

    1999-01-01

    The ballooning instability on open magnetic field lines is given a thorough mathematical analysis. It is shown that resistive bounding ends (endplates) induce the same stability properties as insulating ends. When unstable, the maximal growth rate increases monotonically with boundary resistivity. An interchange instability may be present, and one necessary condition for its stability is that ∫dl/B be constant on pressure surfaces. (This is an equilibrium existence condition for systems with closed magnetic field lines.) Another necessary condition for interchange stability has the same form as in the closed line case. Precise necessary and sufficient stability criteria are given for various types of bounding ends, including insulating, resistive, and perfectly conducting. copyright 1999 American Institute of Physics

  18. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    Miller, R.L.; Waelbroeck, F.W.; Lao, L.L.; Taylor, T.S.

    1994-11-01

    A new code demonstrates the stabilization of MHD ballooning modes by sheared toroidal rotation. A shifted model is used to elucidate the physics and numerically reconstructed equilibria are used to analyze DIII-D discharges. In the ballooning representation, the modes shift periodically along the field line to the next point of unfavorable curvature. The shift frequency (dΩ/dq where Ω is the angular toroidal velocity and q is the safety factor) is proportional to the rotation shear and inversely proportional to the magnetic shear. Stability improves with increasing shift frequency and, in the shifted circle model, direct stable access to the second stability regime occurs when this frequency is a fraction of the Alfven frequency ω A = V A /qR. Shear stabilization is also demonstrated for an equilibrium reconstruction of a DIII-D VH-mode

  19. Simulation of peeling-ballooning modes with pellet injection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S. Y. [College of Physical Science and Technology, Sichuan University, 610064 Chengdu (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Southwestern Institute of Physics, Chengdu 610041 (China); Huang, J.; Sun, T. T.; Tang, C. J. [College of Physical Science and Technology, Sichuan University, 610064 Chengdu (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China)

    2014-11-15

    The influence of pellet ablation on the evolution of peeling-ballooning (P-B) modes is studied with BOUT++ code. The atoms coming from pellet ablation can significantly reshape the plasma pressure profile, so the behaviors of P-B modes and edge localized mode (ELM) are modified dramatically. This paper shows that the energy loss associated with an ELM increases substantially over that without the pellet, if the pellet is deposited at the top of the pedestal. On the contrary, for pellet deposition in the middle of the pedestal region the ELM energy loss can be less.

  20. High-mode-number ballooning modes in a heliotron/torsatron system. II. Stability

    International Nuclear Information System (INIS)

    Nakajima, N.

    1996-01-01

    In heliotron/torsatron systems that have a large Shafranov shift, the local magnetic shear is found to have no stabilizing effect on high-mode-number ballooning modes at the outer side of the torus, even in the region where the global shear is stellarator-like in nature. The disappearance of this stabilization, in combination with the compression of the flux surfaces at the outer side of the torus, leads at relatively low values of the plasma pressure to significant modifications of the stabilizing effect due to magnetic field-line bending on high-mode-number ballooning modes-specifically, that the field-line bending stabilization can be remarkably suppressed or enhanced. In an equilibrium that is slightly Mercier-unstable or completely Mercier-stable due to peaked pressure profiles, such as those used in standard stability calculations, high-mode-number ballooning modes are destabilized due to these modified stability effects, with their eigenfunctions highly localized along the field line. Highly localized mode structures such as these cause the ballooning mode eigenvalues ω 2 to have a strong field line dependence (i.e., α-variation) through the strong dependence of the local magnetic curvature, such that the level surfaces of ω 2 (ψ,θ k ,α) (≤0) become spheroids in (ψ,θ k ,α) space, where ψ labels flux surfaces and θ k is the radial wave number. Because the spheroidal level surfaces for unstable eigenvalues are surrounded by level surfaces for stable eigenvalues of high-mode-number toroidal Alfvacute en eigenmodes, those high-mode-number ballooning modes never lead to low-mode-number modes. In configuration space, these high-mode-number modes are localized in a single toroidal pitch of the helical coils, and hence they may experience substantial stabilization due to finite Larmor radius effects. copyright 1996 American Institute of Physics

  1. Asymptotic stability boundaries of ballooning modes in circular tokamaks

    International Nuclear Information System (INIS)

    Chen, L.; Bondeson, A.; Chance, M.S.

    1987-06-01

    The model ballooning mode equation of Connor, Hastie, and Taylor for large-aspect-ratio circular tokamaks is analyzed in the limit of large pressure gradient, and corresponding expressions for stability boundaries are derived. In particular, it is found that for a fixed radial wave number, there exists an infinite sequence of unstable bands, and that minimizing over the radial wave numbers leads to asymptotic merging between the neighboring bands

  2. Effects of compressibility on the resistive ballooning mode

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.; Cooper, W.A.; Holmes, J.A.; Diamond, P.H.; Similon, P.L.

    1983-09-01

    The linear stability of the resistive ballooning mode, as described by the resistive MHD model, is investigated both analytically and numerically. When the pressure evolution is approximated by fluid convection (reduced MHD model), an instability driven by geodesic curvature, with a growth rate γ approx. eta/sup 1/3/β/sub rho//sup 2/3/, is found. For conditions relevant to the Impurity Study Experiment (ISX-B), it is shown that for modest poloidal beta (β/sub rho/ approx. = 1), high current, and relatively high temperatures, compressibility has a significant stabilizing influence, relative to the pressure convection model, for low toroidal mode number modes. However, at high β/sub rho/ (greater than or equal to 2), low current, and lower temperatures, compressibility has much less effect

  3. Influence of hot beam ions on MHD ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.

    1984-07-01

    It has recently been proposed that the presence of high energy ions from neutral beam injection can have a strong stabilizing effect on kinetically-modified ideal MHD ballooning modes in tokamaks. In order to assess realistically the importance of such effects, a comprehensive kinetic stability analysis, which takes into account the integral equation nature of the basic problem, has been applied to this investigation. In the collisionless limit, the effect of adding small fractions of hot beam ions is indeed found to be strongly stabilizing. On the other hand, for somewhat larger fractions of hot ions, a new beam-driven mode is found to occur with a growth rate comparable in magnitude to the growth rate of the MHD ballooning mode in the absence of hot ions. This implies that there should be an optimal density of hot particles which minimizes the strength of the relevant instabilities. Employing non-Maxwellian equilibrium distribution functions to model the beam species makes a quantitative, but not qualitative, difference in the results. Adding collisions to the calculation tends to reduce considerably the stabilizing effect of the hot ions

  4. Influence of hot beam ions on MHD ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.

    1984-01-01

    It has recently been proposed that the presence of high-energy ions from neutral-beam injection can have a strong stabilizing effect on kinetically modified ideal-MHD ballooning modes in tokamaks. To assess realistically the importance of such effects, a comprehensive kinetic stability analysis, which takes into account the integral equation nature of the basic problem, has been applied to this investigation. In the collisionless limit, the effect of adding small fractions of hot beam ions is indeed found to be strongly stabilizing. On the other hand, for somewhat larger fractions of hot ions, a different, beam-driven root of the mode equations is found to occur with a growth rate comparable in magnitude to the growth rate of the usual MHD ballooning mode in the absence of hot ions. This implies that there should be an optimal density of hot particles which minimizes the strength of the relevant instabilities. Employing non-Maxwellian equilibrium distribution functions to model the beam species makes a quantitative, but not qualitative, difference in the results. Adding collisions to the calculation tends to reduce considerably the stabilizing effect of the hot ions. (author)

  5. Numerical analysis of energetic particle stabilization of ballooning modes in finite-aspect-ratio tokamaks

    International Nuclear Information System (INIS)

    He Qibing; Peng Qiyang; Qu Wenxiao

    1993-09-01

    The effect of energetic trapped particles on the stabilization of ballooning modes in finite-aspect-ratio tokamaks is numerically analyzed. The numerical solution of boundary value problem of an integro-differential equation is successfully obtained by RKF integral method with variable step size. The results show that the instability domain of ballooning modes becomes small along with the increase of energetic particles pressure. The energetic trapped particles can partially or completely suppress the instability of ballooning modes

  6. Ballooning mode second stability region for sequences of tokamak equilibria

    International Nuclear Information System (INIS)

    Sugiyama, L.; Mark, J.W.K.

    A numerical study of several sequences of tokamak equilibria derived from two flux conserving sequences confirms the tendency of high n ideal MHD ballooning modes to stabilize for values of the plasma beta greater than a second critical beta, for sufficiently favorable equilibria. The major stabilizing effect of increasing the inverse rotational transform profile q(Psi) for equilibria with the same flux surface geometry is shown. The unstable region shifts toward larger shear d ln q/d ln γ and the width of the region measured in terms of the poloidal beta or a pressure gradient parameter, for fixed shear, decreases. The smaller aspect ratio sequences are more sensitive to changes in q and have less stringent limits on the attainable value of the plasma beta in the high beta stable region. Finally, the disconnected mode approximation is shown to provide a reasonable description of the second high beta stability boundary

  7. Influence of an energetic-particle component on ballooning modes in an optimized stellarator

    International Nuclear Information System (INIS)

    Nuehrenberg, J.; Zheng, L.J.

    1993-01-01

    Besides quasi-helically symmetric configurations, which have particle drift properties analogous to tokamaks, a second interesting route for stellarator investigations is the choice of the optimized stellarator configuration, which has been adopted for the W7-X stellarator project. Of the many remarkably good properties of the optimized stellarator, two are mentioned here: One is the low geodesic curvature, which leads to a small Pfirsch-Schlueter current and fosters the MHD stability together with a vacuum field magnetic well; the other is that trapped energetic particles are well confined being reflected around the triangular cross section with maximum J - the second invariant. Maximum J configuration could be favorable for the stabilization of the low-frequency thermal-trapped-particle modes. On the other hand, for the energetic particles this means drift-reversal prevailing, and therefore the kinetic energy of the trapped energetic particles is destabilizing. Furthermore, when trapped energetic particles are drift-reversed, two β limits emerge: One is due to the ballooning modes, which relates to the Van Dam-Lee-Nelson limit for EBT; the other is due to the interchange modes. Nevertheless, these two theories predict that - when the core plasma β is high enough - stability may resume. The purpose of this work is to determine whether one of these two limits - the Van Dam-Lee-Nelson limit for ballooning modes - harms the optimized stellarator or not. (author) 12 refs., 1 fig

  8. Global kink and ballooning modes in high-beta systems and stability of toroidal drift modes

    International Nuclear Information System (INIS)

    Galvao, R.M.O.; Goedbloed, J.P.; Rem, J.; Sakanaka, P.H.; Schep, T.J.; Venema, M.

    1983-01-01

    A numerical code (HBT) has been developed which solves for the equilibrium, global stability and high-n stability of plasmas with arbitrary cross-section. Various plasmas are analysed for their stability to these modes in the high-beta limit. Screw-pinch equilibria are stable to high-n ballooning modes up to betas of 18%. The eigenmode equation for drift waves is analysed numerically. The toroidal branch is shown to be destabilized by the non-adiabatic response of trapped and circulating particles. (author)

  9. ELM phenomenon as an interaction between bootstrap-current driven peeling modes and pressure-driven ballooning modes

    International Nuclear Information System (INIS)

    Saarelma, S.; Kurki-Suonio, T.; Guenter, S.; Zehrfeld, H.-P.

    2000-01-01

    An ELMy ASDEX Upgrade plasma equilibrium is reconstructed taking into account the bootstrap current. The peeling mode stability of the equilibrium is numerically analysed using the GATO [1] code, and it is found that the bootstrap current can drive the plasma peeling mode unstable. A high-n ballooning mode stability analysis of the equilibria revealed that, while destabilizing the peeling modes, the bootstrap current has a stabilizing effect on the ballooning modes. A combination of these two instabilities is a possible explanation for the type I ELM phenomenon. A triangularity scan showed that increasing triangularity stabilizes the peeling modes and can produce ELM-free periods observed in the experiments. (author)

  10. Resistive ballooning modes in an axisymmetric toroidal plasma with long mean-free path

    International Nuclear Information System (INIS)

    Connor, J.W.; Chen, L.

    1984-08-01

    Tokamak devices normally operate at such high temperatures that the resistive fluid description is inappropriate. In particular, the collision frequency may be low enough for trapped particles to exist. However, on account of the high conductivity of such plasmas, one can identify two separate scale lengths when discussing resistive ballooning modes. By describing plasma motion on one of these, the connection length, in terms of kinetic theory the dynamics of trapped particles can be incorporated. On the resistive scale length, this leads to a description in terms of modified fluid equations in which trapped particle effects appear. The resulting equations are analyzed and the presence of trapped particles is found to modify the stability properties qualitatively

  11. The effect of pressure anisotropy on ballooning modes in tokamak plasmas

    Science.gov (United States)

    Johnston, A.; Hole, M. J.; Qu, Z. S.; Hezaveh, H.

    2018-06-01

    Edge Localised Modes are thought to be caused by a spectrum of magnetohydrodynamic instabilities, including the ballooning mode. While ballooning modes have been studied extensively both theoretically and experimentally, the focus of the vast majority of this research has been on isotropic plasmas. The prevalence of pressure anisotropy in modern tokamaks thus motivates further study of these modes. This paper presents a numerical analysis of ballooning modes in anisotropic equilibria. The investigation was conducted using the newly-developed codes HELENA+ATF and MISHKA-A, which adds anisotropic physics to equilibria and stability analysis. We have examined the impact of anisotropy on the stability of an n = 30 ballooning mode, confirming results conform to previous calculations in the isotropic limit. Growth rates of ballooning modes in equilibria with different levels of anisotropy were then calculated using the stability code MISHKA-A. The key finding was that the level of anisotropy had a significant impact on ballooning mode growth rates. For {T}\\perp > {T}| | , typical of ICRH heating, the growth rate increases, while for {T}\\perp < {T}| | , typical of neutral beam heating, the growth rate decreases.

  12. Shear flow generation and turbulence suppression by resistive ballooning and resistive interchange modes

    International Nuclear Information System (INIS)

    Guzdar, P.N.; Drake, J.F.

    1993-01-01

    The generation of shear flow by resistive ballooning modes and resistive interchange modes is compared and contrasted using a 3-D fluid code. The resistive ballooning modes give rise to poloidally asymmetric transport and hence drive poloidal rotation due to the Reynold's Stress as well as the anomalous Stringer/Winsor mechanism. On the other hand the resistive interchange mode can drive shear flow only through the Reynold's Stress. The studies show that if the self-consistent sheared flow is suppressed, the resistive ballooning modes give rise to a larger anomalous transport than produced by the resistive interchange modes. Furthermore the shear flow generated by the resistive ballooning modes is larger than that driven by the resistive interchange modes due to the combined effect of the dual mechanisms stated earlier. As a consequence strong suppression of the fluctuations as well as reduction of the transport occurs for resistive ballooning modes. On the other hand, for the resistive interchange modes the level of fluctuation as well as the anomalous transport is not reduced by the self consistent shear flow generated by the Reynold's Stress. This latter result is in agreement with some earlier 3-D simulation of resistive interchange modes

  13. Influence of equilibrium shear flow on peeling-ballooning instability and edge localized mode crash

    International Nuclear Information System (INIS)

    Xi, P. W.; Xu, X. Q.; Wang, X. G.; Xia, T. Y.

    2012-01-01

    The E × B shear flow plays a dual role on peeling-ballooning modes and their subsequently triggered edge localized mode (ELM) crashes. On one hand, the flow shear can stabilize high-n modes and twist the mode in the poloidal direction, constraining the mode's radial extent and reducing the size of the corresponding ELM. On the other hand, the shear flow also introduces the Kelvin-Helmholtz drive, which can destabilize peeling-ballooning modes. The overall effect of equilibrium shear flow on peeling-ballooning modes and ELM crashes depends on the competition between these two effects. When the flow shear is either small or very large, it can reduce ELM size. However, for moderate values of flow shear, the destabilizing effect from the Kelvin-Helmholtz term is dominant and leads to larger ELM crashes.

  14. Criteria for Second Stability for Ballooning Modes in Stellarators

    International Nuclear Information System (INIS)

    Hudson, S.R.; Hegna, C.C.

    2004-01-01

    An expression determining how variations in the pressure-gradient and average magnetic shear affect ballooning stability for a stellarator equilibrium is presented. The procedure for determining the marginal stability boundaries, for each field line, depends only on the equilibrium and a single ballooning eigenfunction calculation. This information is sufficient to determine if increasing pressure-gradient is stabilizing or destabilizing and to predict whether the configuration possess a second stable region

  15. QUANTITATIVE TESTS OF ELMS AS INTERMEDIATE N PEELING-BALLOONING MODES

    International Nuclear Information System (INIS)

    LAO, LL; SNYDER, PB; LEONARD, AW; OSBORNE, TH; PETRIE, TW; FERRON, JR; GROEBNER, RJ; HORTON, LD; KAMADA, Y; MURAKAMI, M; OIKAWA, T; PEARLSTEIN, LD; SAARELMA, S; STJOHN, HE; THOMAS, DM; TURNBULL, AD; WILSON, HR

    2002-01-01

    OAK A271 QUANTITATIVE TESTS OF ELMS AS INTERMEDIATE N PEELING-BALLOONING MODES. Two of the major issues crucial for the design of the next generation tokamak burning plasma devices are the predictability of the edge pedestal height and control of the divertor heat load in H-mode configurations. Both of these are strongly impacted by edge localized modes (ELMs) and their size. A working model for ELMs is that they are intermediate toroidal mode number, n ∼ 5-30, peeling-ballooning modes driven by the large edge pedestal pressure gradient P(prime) and the associated large edge bootstrap current density J BS . the interplay between P(prime) and J BS as a discharge evolves can excite peeling-ballooning modes over a wide spectrum of n. The pedestal current density plays a dual role by stabilizing the high n ballooning modes via opening access to second stability but providing free energy to drive the intermediate n peeling modes. This makes a systematic evaluation of this model particularly challenging. This paper describes recent quantitative tests of this model using experimental data from the DIII-D and the JT-60U tokamaks. These tests are made possible by recent improvements to the ELITE MHD stability code, which allow an efficient evaluation of the unstable peeling-ballooning modes, as well as by improvements to other diagnostic and analysis techniques. Some of the key testable features of this model are: (1) ELMs are triggered when the growth rates of intermediate n MHD modes become significantly large; (2) ELM sizes are related to the radial widths of the unstable modes; (3) the unstable modes have a strong ballooning character localized in the outboard bad curvature region; (4) at high collisionality, ELM size generally becomes smaller because J BS is reduced

  16. High-mode-number ballooning modes in a heliotron/torsatron system: 1, Local magnetic shear

    International Nuclear Information System (INIS)

    Nakajima, N.

    1996-05-01

    The characteristics of the local magnetic shear, a quantity associated with high-mode-number ballooning mode stability, are considered in heliotron/torsatron devices that have a large Shafranov shift. The local magnetic shear is shown to vanish even in the stellarator-like region in which the global magnetic shear is positive. The reason for this is that the degree of the local compression of the poloidal magnetic field on the outer side of the torus, which maintains the toroidal force balance, is reduced in the stellarator-like region of global magnetic shear because the global rotational transform in heliotron/torsatron systems is a radially increasing function. This vanishing of the local magnetic shear is a universal property in heliotron/torsatron systems with a large Shafranov shift since it results from toroidal force balance in the stellarator-like global shear regime that is inherent to such systems

  17. Strong 'Quantum' Chaos in the Global Ballooning Mode Spectrum of Three-dimensional Plasmas

    International Nuclear Information System (INIS)

    Dewar, R. L.; Cuthbert, P.; Ball, R.

    2000-01-01

    The spectrum of ideal magnetohydrodynamic (MHD) pressure-driven (ballooning) modes in strongly nonaxisymmetric toroidal systems is difficult to analyze numerically owing to the singular nature of ideal MHD caused by lack of an inherent scale length. In this paper, ideal MHD is regularized by using a k-space cutoff, making the ray tracing for the WKB ballooning formalism a chaotic Hamiltonian billiard problem. The minimum width of the toroidal Fourier spectrum needed for resolving toroidally localized ballooning modes with a global eigenvalue code is estimated from the Weyl formula. This phase-space-volume estimation method is applied to ballooning-unstable plasma equilibria in the H-1NF helical axis stellarator and the Large Helical Device (LHD)

  18. Correlation of the tokamak H-mode density limit with ballooning stability at the separatrix

    Science.gov (United States)

    Eich, T.; Goldston, R. J.; Kallenbach, A.; Sieglin, B.; Sun, H. J.; ASDEX Upgrade Team; Contributors, JET

    2018-03-01

    We show for JET and ASDEX Upgrade, based on Thomson-scattering measurements, a clear correlation of the density limit of the tokamak H-mode high-confinement regime with the approach to the ideal ballooning instability threshold at the periphery of the plasma. It is shown that the MHD ballooning parameter at the separatrix position α_sep increases about linearly with the separatrix density normalized to Greenwald density, n_e, sep/n_GW for a wide range of discharge parameters in both devices. The observed operational space is found to reach at maximum n_e, sep/n_GW≈ 0.4 -0.5 at values for α_sep≈ 2 -2.5, in the range of theoretical predictions for ballooning instability. This work supports the hypothesis that the H-mode density limit may be set by ballooning stability at the separatrix.

  19. Ballooning mode instability due to slowed-down ALPHA -particles and associated transport

    International Nuclear Information System (INIS)

    Itoh, Sanae; Itoh, Kimitaka; Tuda, Takashi; Tokuda, Shinji.

    1982-01-01

    The microscopic stability of tokamak plasma, which contains slowed-down alpha-particles and the anomalous fluxes enhanced by the fluctuation, was studied. The local maxwellian distribution with the density inhomogeneity as the equilibrium distribution of electrons, ions and alpha-particles was closen. In the zero-beta limit, two branches of eigenmodes, which are electrostatic, were obtained. The electrostatic ballooning mode became unstable by the grad B drift of particles in the toroidal plasma. It should be noted that there was no critical alpha-particle density and no critical beta-value for the onset of the instability in toroidal plasma even in the presence of the magnetic shear. When the beta-value exceeded the critical beta-value of the MHD ballooning mode, the growth rate approached to that of the MHD mode, and the mode sturcture became very close to that of the MHD mode. The unstable mode in toroidal plasma was the ballooning mode, and was unstable for all plasma parameters. The associated cross-field transport by the ballooning mode is considered. It was found that if the distribution function was assumed to be the birth distribution, the loss rate was very slow and slower than the slowing down time. The effect of alpha-particles on the large scale MHD activity of plasma is discussed. (Kato, T.)

  20. Kinetic stability of internal kink mode

    International Nuclear Information System (INIS)

    Romanelli, F.; Fogaccia, G.

    1993-01-01

    With reference to studies of the attainment of ignited operations on devices like ITER (International Thermonuclear Experimental Reactor), the stability of the internal kink mode is re-investigated by taking into account the contribution of perpendicular compressibility, obtained by solving the drift kinetic equation. The resulting stability condition yields threshold values typically larger than the conventional Bussac criterion. For the case of ultra-flat safety factor profiles, the mode can be stable also in the absence of line-bending

  1. Theory of energetic trapped particle-induced resistive interchange-ballooning modes

    International Nuclear Information System (INIS)

    Biglari, H.; Chen, L.

    1986-02-01

    A theory describing the influence of energetic trapped particles on resistive interchange-ballooning modes in tokamaks is presented. It is shown that a population of hot particles trapped in the region of adverse curvature can resonantly interact with and destabilize the resistive interchange mode, which is stable in their absence because of favorable average curvature. The mode is different from the usual resistive interchange mode not only in its destabilization mechanism, but also in that it has a real component to its frequency comparable to the precessional drift frequency of the rapidly circulating energetic species. Corresponding growth rate and threshold conditions for this trapped-particle-driven instability are derived and finite banana width effects are shown to have a stabilizing effect on the mode. Finally, the ballooning/tearing dispersion relation is generalized to include hot particles, so that both the ideal and the resistive modes are derivable in the appropriate limits. 23 refs., 7 figs

  2. Stabilisation of ballooning modes in torsatrons with an externally applied toroidal current

    International Nuclear Information System (INIS)

    Cooper, W.A.

    1996-01-01

    It has been found that ideal ballooning modes can impose very restrictive volume average β limits in torsatrons much below the typical values close to 5% that are required to be economically realisable as reactor systems and it has been shown that externally applied toroidal currents that are peaked can destabilise the Mercier criterion in this type of configuration. We will show here that if the applied currents are hollow, they can stabilise the ballooning modes without triggering Mercier instabilities and as a result raise the limiting β* from 2% to 5%. (author) 3 figs., 10 refs

  3. Destabilization of a peeling-ballooning mode by a toroidal rotation in tokamaks

    International Nuclear Information System (INIS)

    Aiba, N.; Hirota, M.; Tokuda, S.; Furukawa, M.

    2009-01-01

    Full text: From the viewpoint of the heat load on the divertor, Type-I edge localized mode (ELM) needs to be suppressed or the amplitude of this ELM needs to be reduced. In JT-60U, some experimental results showed that the ELM frequency depends on the toroidal rotation, and the rapid rotation in the counter direction of the plasma current changes from Type-I ELM to Grassy ELM, whose frequency is high and the amplitude is small. Recent experimental and theoretical/numerical studies in a static system have identified that both Type-I and Grassy ELMs are considered ideal magnetohydrodynamic (MHD) modes destabilizing near the plasma surface, called peeling-ballooning modes. To investigate the mechanism of the change of ELM frequency by a toroidal rotation, theoretical and numerical analyses are important for understanding the toroidal rotation effects on the peeling-ballooning mode. Previous works about the toroidal rotation effect on the edge MHD stability have illustrated that the toroidal rotation with shear can destabilize low/intermediate-n (<50) modes but can stabilize high-n modes, where n is the toroidal mode number. The stabilization of the high-n mode can be understood qualitatively in analogy with the infinite-n ballooning mode case. However, the destabilizing mechanism of the low/intermediate-n mode is not still clarified, and to understand the stability property related to ELM suppression/mitigation, it is important to clarify this destabilizing mechanism. In this paper, we investigate numerically the destabilizing effect of a toroidal rotation on the peeling-ballooning mode with a newly developed code MINERVA, which solves the Frieman-Rotenberg equation. Particularly, we pay attention to the effect of the centrifuged force on not only equilibrium but also change of equation of motion. (author)

  4. Resistive ballooning modes in W7-AS and W7-X

    International Nuclear Information System (INIS)

    Kaiser, R.

    1993-01-01

    'Critical' pressure gradients due to resistive ballooning modes and their growth rates were computed for the W7-AS stellarator and for a HELIAS configuration with W7-X parameters, and the two configurations were compared. The results are based on the evaluation of a fourth order magnetic differential equation along closed magnetic field lines. The numerical procedure applying a variational approach uses the 'Garching resistive ballooning code', GARBO, which was originally developed for the stability analysis of axisymmetric plasmas. Concerning purely growing modes, this analysis shows that the favourable stability properties of W7-X, already optimized with respect to ideal ballooning modes, persist in the resistive regime: the destabilizing effect of resistivity is largely compensated by the stabilizing contribution of plasma compression. As a consequence, the ideal β limit continues only moderately shifted in the resistive case and likewise ideal ballooning stable equilibria (up to β 0 ≅ 5%) do not become resistively unstable. The situation is different for W7-AS. Greater resistive effects (in comparison with W7-X) are found in a configuration that is already ideally much more unstable. A basic feature in resistive calculations is the occurrence of overstable modes. These modes no longer show a stability threshold and, for realistic values of pressure and resistivity, linear instability is obtained for W7-AS as well as for W7-X, with growth rates and oscillation frequencies in the kilo-Hertz range. (author). 29 refs, 13 figs

  5. ELMs and constraints on the H-mode pedestal: A model based on peeling-ballooning modes

    International Nuclear Information System (INIS)

    Snyder, P.B.; Ferron, J.R.; Wilson, H.R.

    2003-01-01

    We propose a model for Edge Localized Modes (ELMs) and pedestal constraint based upon theoretical analysis of instabilities which can limit the pedestal height and drive ELMs. The sharp pressure gradients, and resulting bootstrap current, in the pedestal region provide free energy to drive peeling and ballooning modes. The interaction of peeling-ballooning coupling, ballooning mode second stability, and finite-Larmor-radius effects results in coupled peeling-ballooning modes of intermediate wavelength generally being the limiting instability. A highly efficient new MHD code, ELITE, is used to calculate quantitative stability constraints on the pedestal, including con straits on the pedestal height. Because of the impact of collisionality on the bootstrap current, these pedestal constraints are dependant on the density and temperature separately, rather than simply on the pressure. A model of various ELM types is developed, and quantitatively compared to data. A number of observations agree with predictions, including ELM onset times, ELM depth and variation in pedestal height with collisionality and discharge shape. Stability analysis of series of model equilibria are used both o predict and interpret pedestal trends in existing experiments and to project pedestal constraints for future burning plasma tokamak designs. (author)

  6. Ballooning mode stability for self-consistent pressure and current profiles at the H-mode edge

    International Nuclear Information System (INIS)

    Miller, R.L.; Lin-Liu, Y.R.; Osborne, T.H.; Taylor, T.S.

    1997-11-01

    The edge pressure gradient (H-mode pedestal) for computed equilibria in which the current density profile is consistent with the bootstrap current may not be limited by the first regime ballooning limit. The transition to second stability is easier for: higher elongation, intermediate triangularity, larger ratio, pedestal at larger radius, narrower pedestal width, higher q 95 , and lower collisionality

  7. Effects of ion temperature fluctuations on the stability of resistive ballooning modes

    International Nuclear Information System (INIS)

    Singh, R.; Nordman, H.; Jarmen, A.; Weiland, J.

    1996-01-01

    The influence of ion temperature fluctuations on the stability of resistive drift- and ballooning-modes is investigated using a two-fluid model. The Eigenmode equations are derived and solved analytically in a low beta model equilibrium. Parameters relevant to L-mode edge plasmas from the Texas Experimental Tokamak are used. The resistive modes are found to be destabilized by ion temperature fluctuations over a broad range of mode numbers. The scaling of the growth rate with magnetic shear and mode number is elucidated. 13 refs, 4 figs

  8. Pseudo-MHD ballooning modes in tokamak plasmas

    International Nuclear Information System (INIS)

    Callen, J.D.; Hegna, C.C.

    1996-08-01

    The MHD description of a plasma is extended to allow electrons to have both fluid-like and adiabatic-regime responses within an instability eigenmode. In the resultant open-quotes pseudo-MHDclose quotes model, magnetic field line bending is reduced in the adiabatic electron regime. This makes possible a new class of ballooning-type, long parallel extent, MHD-like instabilities in tokamak plasmas for α > s 2 (2 7/3 /9) (r p /R 0 ) or-d√Β/dr > (2 1/6 /3)(s/ R 0q ), which is well below the ideal-MHD stability boundary. The marginally stable pressure profile is similar in both magnitude and shape to that observed in ohmically heated tokamak plasmas

  9. Transition to chaos for ballooning modes stabilized by finite Larmor radius effects

    Energy Technology Data Exchange (ETDEWEB)

    Weiland, J; Wilhelmsson, H [Chalmers Tekniska Hoegskola, Goeteborg (Sweden). Institutionen foer Elektromagnetisk Faeltteori

    1983-08-01

    The nonlinear dynamics of interacting ballooning modes, stabilized by finite Larmor radius effects is analyzed in terms of a set of equations, which exhibit stochastic properties. These are explicitly shown to depend on the balance between shear and driving pressure force. The onset of bifurcations and chaotic behaviour are directly identified with certain values of parameters characterizing the physical system.

  10. Anderson localization of ballooning modes, quantum chaos and the stability of compact quasiaxially symmetric stellarators

    International Nuclear Information System (INIS)

    Redi, M.H.; Johnson, J.L.; Klasky, S.; Canik, J.; Dewar, R.L.; Cooper, W.A.

    2002-01-01

    The radially local magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), is examined just above the ballooning beta limit with a method that can lead to estimates of global stability. Here MHD stability is analyzed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in the 3-space (s,α,θ k ); s is the edge normalized toroidal flux, α is the field line variable, and θ k is the perpendicular wave vector or ballooning parameter. Broken symmetry, i.e., deviations from axisymmetry, in the stellarator magnetic field geometry causes localization of the ballooning mode eigenfunction, and gives rise to new types of nonsymmetric eigenvalue isosurfaces in both the stable and unstable spectrum. For eigenvalues far above the marginal point, isosurfaces are topologically spherical, indicative of strong 'quantum chaos'. The complexity of QAS marginal isosurfaces suggests that finite Larmor radius stabilization estimates will be difficult and that fully three-dimensional, high-n MHD computations are required to predict the beta limit

  11. Proliferation kinetics of paramecium tetraurelia in balloon-borne experiments

    International Nuclear Information System (INIS)

    Croute, F.; Soleilhavoup, J.P.; Vidal, S.; Rousseille, R.; Planel, H.

    1982-01-01

    Experiments were carried out to demonstrate the effect of cosmic radiation, at a balloon-flight ceiling of about 36,500 m (120,000 ft) on single-cell organism proliferation. Paramecium tetraurelia were placed in air-tight containers and maintained at 25 degrees +/- 0.1 degrees C. Cellular growth was determined by cell count, either after recovery or during the flight, by means of an automatic fixation device. Dosimetry was performed by a tissue equivalent proportional counter and was of about 0.5 mrad/h. Flight ceiling duration ranged from 48 min - 22 h. A secondary stimulating effect of growth rate, preceded by a temporary decrease, was observed after recovery. Because of the high bacterial concentration in the trans-Mediterranean flight culture medium, the temporary drop of the growth rate, due to the radiolysis products, disappears. Researchers consider that the stimulating effect can be the result of enzymatic intracellular scavenging of radiolysis products generated in the cell

  12. Global structures of Alfven-ballooning modes in magnetospheric plasmas

    International Nuclear Information System (INIS)

    Vetoulis, G.; Chen, Liu.

    1994-03-01

    The authors show that a steep plasma pressure gradient can lead to radially localized Alfven modes, which are damped through coupling to filed line resonances. These have been called drift Alfven balloning modes (DABM) and are the prime candidates to explain Pc4-Pc5 geomagnetic pulsations observed during storms. A strong dependence of the damping rate on the azimuthal wave number m is established, as well as on the equilibrium profile. A minimum azimuthal mode number can be found for the DABM to be radially trapped. The authors find that higher m DABMs are better localized, which is consistent with high-m observations

  13. Edge kink/ballooning mode stability in tokamaks with separatrix

    International Nuclear Information System (INIS)

    Medvedev, S Yu; Martynov, A A; Martin, Y R; Sauter, O; Villard, L

    2006-01-01

    Stability limits against external kink modes driven by large current density and pressure gradient values in the pedestal region are investigated for tokamak plasmas with separatrix. Stability diagrams for modes with different toroidal wave numbers under variations of pressure gradient and current density in the pedestal region are presented for several equilibrium configurations related to TCV. A scaling for the toroidal wave number of the most unstable mode is proposed. The influence of the plasma cross-section geometry on the stability limits is discussed

  14. Marginal Stability Diagrams for Infinite-n Ballooning Modes in Quasi-symmetric Stellarators

    International Nuclear Information System (INIS)

    Hudson, S.R.; Hegna, C.C.; Torasso, R.; Ware, A.

    2003-01-01

    By perturbing the pressure and rotational-transform profiles at a selected surface in a given equilibrium, and by inducing a coordinate variation such that the perturbed state is in equilibrium, a family of magnetohydrodynamic equilibria local to the surface and parameterized by the pressure gradient and shear is constructed for arbitrary stellarator geometry. The geometry of the surface is not changed. The perturbed equilibria are analyzed for infinite-n ballooning stability and marginal stability diagrams are constructed that are analogous to the (s; alpha) diagrams constructed for axi-symmetric configurations. The method describes how pressure and rotational-transform gradients influence the local shear, which in turn influences the ballooning stability. Stability diagrams for the quasi-axially-symmetric NCSX (National Compact Stellarator Experiment), a quasi-poloidally-symmetric configuration and the quasi-helically-symmetric HSX (Helically Symmetric Experiment) are presented. Regions of second-stability are observed in both NCSX and the quasi-poloidal configuration, whereas no second stable region is observed for the quasi-helically symmetric device. To explain the different regions of stability, the curvature and local shear of the quasi-poloidal configuration are analyzed. The results are seemingly consistent with the simple explanation: ballooning instability results when the local shear is small in regions of bad curvature. Examples will be given that show that the structure, and stability, of the ballooning mode is determined by the structure of the potential function arising in the Schroedinger form of the ballooning equation

  15. Kinetic slow mode-type solitons

    Directory of Open Access Journals (Sweden)

    K. Baumgärtel

    2005-01-01

    Full Text Available One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-β plasma (βi=0.25 and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions (Stasiewicz et al., 2003; Stasiewicz, 2004 against kinetic theory. In the simulations, a variety of strongly oblique, large amplitude, solitons are seen, including solitons with Alfvenic polarization, similar to those predicted by the Hall-MHD theory, and robust, almost non-propagating, solitary structures of slow magnetosonic type with strong magnetic field depressions and perpendicular ion heating, which have no counterpart in fluid theory. The results support the soliton-based interpretation of the Cluster observations, but reveal substantial deficiencies of Hall-MHD theory in describing slow mode-type solitons in a plasma of moderate beta.

  16. The stability of ideal and resistive ballooning modes in the presence of equilibrium flows

    International Nuclear Information System (INIS)

    Sundaram, A.K.; Sen, A.

    1989-01-01

    Ideal and resistive ballooning modes have been the topic of extensive study in view of their important role in constraining plasma β or in causing degradation in electron energy confinement time. Much of these works in the literature have been done for static equilibrium. Recently several experiments on ISX, PDX and currently on TFTR and JET have demonstrated the presence of toroidal and poloidal flows due to asymmetry in the neutral beam injection (NBI). Also equilibrium flows can arise through diffusive processes in tokamak plasmas. Such flows induced by external sources or dissipative processes affect the form and location of the magnetic surfaces and also modify the density and pressure profiles in the equilibrium. In this paper, we therefore examine the effect of mass flows on the evolution of high (m,n) ideal and resistive ballooning modes using the simplified MHD equations. (author) 2 refs

  17. Fluid analysis of electromagnetic ballooning modes in a fully toroidal description

    International Nuclear Information System (INIS)

    Andersson, P.; Weiland, J.

    1986-01-01

    A comparatively complete two fluid description of collisionless electromagnetic ballooning modes has been derived. Using an unexpanded ion density response it has been shown that a necessary and sufficient condition for an instability below the MHD/BETA/ limit is the presence of an ion temperature gradient exceeding a threshold. The cause of this instability has been identified and an analytical dispersion relation is given. (authors)

  18. Simulations of peeling-ballooning modes with electron cyclotron resonance heating

    International Nuclear Information System (INIS)

    Huang, J.; Tang, C. J.; Chen, S. Y.

    2016-01-01

    The effects of the deposited power and deposited position of Electron Cyclotron Resonance Heating (ECRH) on Peeling-Ballooning (P-B) modes are simulated using BOUT++ code in this paper. The simulation results show that as the deposited position moves from the top to the bottom of the pedestal, the edge localized mode (ELM) size decreases first and then increases, finally decreases again. For ECRH with different deposited power, the effects on P-B modes are similar if they have the same peak value of the power deposition profile. These results show that the effects of ECRH on P-B modes are primarily determined by the change in pressure profile caused by ECRH. As long as ECRH can lead to large enough change in pressure profile, ECRH can efficiently affect the dynamics of P-B modes.

  19. Simulations of peeling-ballooning modes with electron cyclotron resonance heating

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J.; Tang, C. J. [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Chen, S. Y., E-mail: sychen531@163.com [College of Physical Science and Technology, Sichuan University, Chengdu 610065 (China); Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Southwestern Institute of Physics, Chengdu 610041 (China)

    2016-05-15

    The effects of the deposited power and deposited position of Electron Cyclotron Resonance Heating (ECRH) on Peeling-Ballooning (P-B) modes are simulated using BOUT++ code in this paper. The simulation results show that as the deposited position moves from the top to the bottom of the pedestal, the edge localized mode (ELM) size decreases first and then increases, finally decreases again. For ECRH with different deposited power, the effects on P-B modes are similar if they have the same peak value of the power deposition profile. These results show that the effects of ECRH on P-B modes are primarily determined by the change in pressure profile caused by ECRH. As long as ECRH can lead to large enough change in pressure profile, ECRH can efficiently affect the dynamics of P-B modes.

  20. ELMs and constraints on the H-mode pedestal: A model based on peeling-ballooning modes

    International Nuclear Information System (INIS)

    Snyder, P.B.

    2002-01-01

    Maximizing the pedestal height while maintaining acceptable ELMs is a key issue for optimizing tokamak performance. We present a model for ELMs and pedestal constraints based upon theoretical analysis of edge instabilities which can limit the pedestal height and drive ELMs. Sharp pedestal pressure gradients drive large bootstrap currents which play a complex dual role in the stability physics. Consequently, the dominant modes are often intermediate-n coupled 'peeling-ballooning' modes, driven both by current and the pressure gradient. A highly efficient new MHD code, ELITE, is used to study these modes, and calculate quantitative stability constraints on the pedestal, including direct constraints on the pedestal height. A model of various ELM types is developed, and quantitatively compared to data from several tokamaks. A number of observations agree with predictions, including ELM onset times, ELM depth, and variation in pedestal height with discharge shape. Projections of pedestal stability constraints for Next Step designs, and nonlinear simulations of peeling-ballooning modes using the BOUT code are also presented. (author)

  1. Slowest kinetic modes revealed by metabasin renormalization

    Science.gov (United States)

    Okushima, Teruaki; Niiyama, Tomoaki; Ikeda, Kensuke S.; Shimizu, Yasushi

    2018-02-01

    Understanding the slowest relaxations of complex systems, such as relaxation of glass-forming materials, diffusion in nanoclusters, and folding of biomolecules, is important for physics, chemistry, and biology. For a kinetic system, the relaxation modes are determined by diagonalizing its transition rate matrix. However, for realistic systems of interest, numerical diagonalization, as well as extracting physical understanding from the diagonalization results, is difficult due to the high dimensionality. Here, we develop an alternative and generally applicable method of extracting the long-time scale relaxation dynamics by combining the metabasin analysis of Okushima et al. [Phys. Rev. E 80, 036112 (2009), 10.1103/PhysRevE.80.036112] and a Jacobi method. We test the method on an illustrative model of a four-funnel model, for which we obtain a renormalized kinematic equation of much lower dimension sufficient for determining slow relaxation modes precisely. The method is successfully applied to the vacancy transport problem in ionic nanoparticles [Niiyama et al., Chem. Phys. Lett. 654, 52 (2016), 10.1016/j.cplett.2016.04.088], allowing a clear physical interpretation that the final relaxation consists of two successive, characteristic processes.

  2. Theory of semicollisional kinetic Alfven modes in sheared magnetic fields

    International Nuclear Information System (INIS)

    Hahm, T.S.; Chen, L.

    1985-02-01

    The spectra of the semicollisional kinetic Alfven modes in a sheared slab geometry are investigated, including the effects of finite ion Larmor radius and diamagnetic drift frequencies. The eigenfrequencies of the damped modes are derived analytically via asymptotic analyses. In particular, as one reduces the resistivity, we find that, due to finite ion Larmor radius effects, the damped mode frequencies asymptotically approach finite real values corresponding to the end points of the kinetic Alfven continuum

  3. Effect of ballooning modes on thermal transport and magnetic field diffusion in the solar corona

    International Nuclear Information System (INIS)

    Strauss, H.R.

    1989-01-01

    Presently favored mechanisms of coronal heating: current sheet dissipation and Alfven wave resonant heating: deposit heat in thin layers. Classical thermal conduction cannot explain how heat is transported across the magnetic field. If heating occurs in thin layers, large pressure gradients can be created, which can give rise to ballooning modes. These instabilities are caused by the pressure gradient and the curvature of the magnetic field, and are stabilized by magnetic tension. The modes are broad band in wavelength and should produce turbulence. A mixing length expression for the turbulent heat transport shows that it is more than adequate to rapidly convect heat into much broader layers. Furthermore, the turbulent resistivity implies that heating occurs over most of the width of these broadened layers. The broadening also implies that much shorter time scales are required for heating. The β values in the corona suggest that 1--10 turbulent layers are formed in typical loop or arch structures. copyright American Geophysical Union 1989

  4. Five-field simulations of peeling-ballooning modes using BOUT++ code

    Energy Technology Data Exchange (ETDEWEB)

    Xia, T. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2013-05-15

    The simulations of edge localized modes (ELMs) with a 5-field peeling-ballooning (P-B) model using BOUT++ code are reported in this paper. In order to study the particle and energy transport in the pedestal region, the pressure equation is separated into ion density and ion and electron temperature equations. Through the simulations, the length scale L{sub n} of the gradient of equilibrium density n{sub i0} is found to destabilize the P-B modes in ideal MHD model. With ion diamagnetic effects, the growth rate is inversely proportional to n{sub i0} at medium toroidal mode number n. For the nonlinear simulations, the gradient of n{sub i0} in the pedestal region can more than double the ELM size. This increasing effect can be suppressed by thermal diffusivities χ{sub ∥}, employing the flux limited expression. Thermal diffusivities are sufficient to suppress the perturbations at the top of pedestal region. These suppressing effects lead to smaller ELM size of P-B modes.

  5. Numerical linear analysis of the effects of diamagnetic and shear flow on ballooning modes

    Science.gov (United States)

    Yanqing, HUANG; Tianyang, XIA; Bin, GUI

    2018-04-01

    The linear analysis of the influence of diamagnetic effect and toroidal rotation at the edge of tokamak plasmas with BOUT++ is discussed in this paper. This analysis is done by solving the dispersion relation, which is calculated through the numerical integration of the terms with different physics. This method is able to reveal the contributions of the different terms to the total growth rate. The diamagnetic effect stabilizes the ideal ballooning modes through inhibiting the contribution of curvature. The toroidal rotation effect is also able to suppress the curvature-driving term, and the stronger shearing rate leads to a stronger stabilization effect. In addition, through linear analysis using the energy form, the curvature-driving term provides the free energy absorbed by the line-bending term, diamagnetic term and convective term.

  6. Dependence of ideal MHD kink and ballooning modes on plasma shape and profiles in tokamaks

    International Nuclear Information System (INIS)

    Todd, A.M.M.; Manickam, J.; Okabayashi, M.; Chance, M.S.; Grimm, R.C.; Greene, J.M.; Johnson, J.L.

    1978-08-01

    Extensive numerical studies of ideal MHD instabilities have been carried out to gain insight into the parametric dependence of critical β's in tokamaks. The large number of interrelated equilibrium quantities involved in establishing a critical β has demanded a careful, systematic survey in order to isolate this dependence. The results of this survey establish the scaling with geometrical quantities including aspect ratio, elongation, and triangularity in the parameter regimes appropriate for both current and reactor-sized plasmas. A moderate dependence on the pressure profile and a strong variation with the current profile is found. The principal result is that for aspect ratio R/a approximately equal to 3, critical β's are of the order of 2% for circular cross sections and 5% for plasmas with elongation K approximately equal to 2; somewhat higher values could be achieved with more optimal shaping. Finally, sequences of equilibria have been analyzed to compare critical β as a function of toroidal mode number n. We conclude that the infinite-n analytic ballooning theory provides a sufficient condition for ideal MHD internal mode stability. Low-n free boundary modes appear to set a lower limit

  7. The effects of sloshing energetic particles on ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    Stotler, D.P.; Berk, H.L.

    1986-10-01

    Distributions that give rise to energetic trapped particle pressures peaked in the ''good curvature'' region of a tokamak (sloshing distributions) are examined in an attempt to find stable regimes for both the magnetohydrodynamic (MHD) and precessional modes. It is the precessional drift destabilization of ballooning modes that inhibits bridging the unstable gap to second stability by the use of deeply-trapped energetic particles unless the hot particles have an extremely large energy (∼0.35 MeV for a tokamak like PDX). Unfortunately, our calculations indicate that the sloshing particles do not have a significant stabilizing effect. An analytic treatment shows that complete stability can be found only if the sign of the energetic particle magnetic drift-frequency can be reversed from its value in vacuum bad curvature without hot species diamagnetism. This is difficult to do in a tokamak because of the destabilizing contribution of the geodesic curvature to the drift frequency. Furthermore, for each of the two sloshing distributions employed (one contains only trapped particles; the other includes trapped and passing particles), a new ''continuum instability'' (where asymptotically along the field line the mode is a propagating plane wave) is found to be driven by geodesic curvature. These results indicate that energetic sloshing particles are not able to bridge the unstable gap to second stability

  8. Predictive transport modelling of type I ELMy H-mode dynamics using a theory-motivated combined ballooning-peeling model

    International Nuclear Information System (INIS)

    Loennroth, J-S; Parail, V; Dnestrovskij, A; Figarella, C; Garbet, X; Wilson, H

    2004-01-01

    This paper discusses predictive transport simulations of the type I ELMy high confinement mode (H-mode) with a theory-motivated edge localized mode (ELM) model based on linear ballooning and peeling mode stability theory. In the model, a total mode amplitude is calculated as a sum of the individual mode amplitudes given by two separate linear differential equations for the ballooning and peeling mode amplitudes. The ballooning and peeling mode growth rates are represented by mutually analogous terms, which differ from zero upon the violation of a critical pressure gradient and an analytical peeling mode stability criterion, respectively. The damping of the modes due to non-ideal magnetohydrodynamic effects is controlled by a term driving the mode amplitude towards the level of background fluctuations. Coupled to simulations with the JETTO transport code, the model qualitatively reproduces the experimental dynamics of type I ELMy H-mode, including an ELM frequency that increases with the external heating power. The dynamics of individual ELM cycles is studied. Each ELM is usually triggered by a ballooning mode instability. The ballooning phase of the ELM reduces the pressure gradient enough to make the plasma peeling unstable, whereby the ELM continues driven by the peeling mode instability, until the edge current density has been depleted to a stable level. Simulations with current ramp-up and ramp-down are studied as examples of situations in which pure peeling and pure ballooning mode ELMs, respectively, can be obtained. The sensitivity with respect to the ballooning and peeling mode growth rates is investigated. Some consideration is also given to an alternative formulation of the model as well as to a pure peeling model

  9. Nonlinear simulation of tearing mode and m=1 kink mode based on kinetic RMHD model

    International Nuclear Information System (INIS)

    Yagi, M.; Yoshida, S.; Itoh, S.-I.; Naitou, H.; Nagahara, H.; Leboeuf, J.-N.; Itoh, K.; Matsumoto, T.; Tokuda, S.; Azumi, M.

    2005-01-01

    In this paper, we investigate dynamics of sawtooth oscillation and neoclassical tearing modes based on kinetic RMHD model, putting an emphasis on interaction with microscopic and transport processes. The simulation results show that the assumption in the conventional theory of neoclassical tearing mode is rather rude. (author)

  10. Equilibrium and ballooning mode stability of an axisymmetric tensor pressure tokamak

    International Nuclear Information System (INIS)

    Cooper, W.A.; Bateman, G.; Nelson, D.B.; Kammash, T.

    1980-08-01

    A force balance relation, a representation for the poloidal beta (β/sub p/), and expressions for the current densities are derived from the MHD equilibrium relations for an axisymmetric tensor pressure tokamak. Perpendicular and parallel beam pressure components are evaluated from a distribution function that models high energy neutral particle injection. A double adiabatic energy principle is derived from that of Kruskal and Oberman, with correction terms added. The energy principle is then applied to an arbitrary cross-section axisymmetric tokamak to examine ballooning instabilities of large toroidal mode number. The resulting Euler equation is remarkably similar to that of ideal MHD. Although the field-bending term is virtually unaltered, the driving term is modified because the pressures are no longer constant on a flux surface. Either a necessary or a sufficient marginal stability criterion for a guiding center plasma can be derived from this equation whenever an additional stabilizing element unique to the double adiabatic theory is either kept or neglected, respectively

  11. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Verscharen, Daniel [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Wicks, Robert T., E-mail: daniel.verscharen@unh.edu, E-mail: christopher.chen@imperial.ac.uk, E-mail: r.wicks@ucl.ac.uk [Mullard Space Science Laboratory, University College London, London WC1E 6BT (United Kingdom)

    2017-05-10

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  12. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    International Nuclear Information System (INIS)

    Verscharen, Daniel; Chen, Christopher H. K.; Wicks, Robert T.

    2017-01-01

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  13. Comparative study of proliferation kinetics of paramecium tetraurelia aboard a satellite and a balloon flight

    Energy Technology Data Exchange (ETDEWEB)

    Tixador, R.; Richoilley, G.; Gasset, G.; Planel, H. (Faculte de Medecine, Toulouse-Purpan (France))

    1982-05-17

    A possible effect of cosmic rays on cell proliferation was investigated in cultures of Paramecium tetraurelia during a stratospheric balloon flight, with the techniques already used for the CYTOS experiments, performed aboard the orbital station Salyut 6. The results show that the stimulating effect of space on cell proliferation, reported in the CYTOS experiments, also occurs in the balloon flight. The respective roles of cosmic rays and weightlesness in the biological responses are discussed.

  14. Comparative study of proliferation kinetics of paramecium tetraurelia aboard a satellite and a balloon flight

    International Nuclear Information System (INIS)

    Tixador, Rene; Richoilley, Gerard; Gasset, Gilbert; Planel, Hubert

    1982-01-01

    A possible effect of cosmic rays on cell proliferation was investigated in cultures of Paramecium tetraurelia during a stratospheric balloon flight, with the techniques already used for the CYTOS experiments, performed aboard the orbital station Salyut 6. The results show that the stimulating effect of space on cell proliferation, reported in the CYTOS experiments, also occurs in the balloon flight. The respective roles of cosmic rays and weightlesness in the biological responses are discussed [fr

  15. Hydrodynamization and transient modes of expanding plasma in kinetic theory

    CERN Document Server

    Heller, Michal P.; Spalinski, Michal

    2016-01-01

    We study the transition to hydrodynamics in a weakly-coupled model of quark-gluon plasma given by kinetic theory in the relaxation time approximation. Our studies uncover qualitative similarities to the results on hydrodynamization in strongly coupled gauge theories. In particular, we demonstrate that the gradient expansion in this model has vanishing radius of convergence. The asymptotic character of the hydrodynamic gradient expansion is crucial for the recently discovered applicability of hydrodynamics at large gradients. Furthermore, the analysis of the resurgent properties of the series provides, quite remarkably, indication for the existence of a novel transient, damped oscillatory mode of expanding plasmas in kinetic theory.

  16. Linear and nonlinear studies of resistive-ballooning modes in a tokamak edge plasma with scrape-off layer

    International Nuclear Information System (INIS)

    Lau, Y.T.; Novakovskii, S.V.; Drake, J.F.

    1996-01-01

    We will present 2D linear and 3D nonlinear studies of resistive-ballooning modes in tokamak edge plasmas which include a closed flux region, as well as a limiter scrape-off layer (SOL) region. These studies therefore go beyond most earlier work, where the stability of the edge in the closed flux region and in the SOL have been considered separately. A 2D linear code, 2D-BALLOON, examines the stability of these curvature driven modes and provides the complete 2D eigenfunction spanning the closed flux surface region as well the open field line region. The sheath boundary condition in the SOL introduces an important new parameter λ = (m e /m i ) 1/2 v ei qR/v Te . This parameter plays a significant role in determining the stability of these modes in both the closed flux and SOL regions because of the radial coupling across the last closed flux surface (LCFS). For small λ the spectrum of unstable modes is broad and extends into the low toroidal mode number exclamation point regime where the spatial structure is flute-like. The amplitude for these modes is larger in the SOL compared to the closed flux region. However when A is increased, the low mode numbers are strongly stabilized and the high mode numbers which are strongly ballooning are the dominant modes. In this regime the radial modes straddle the LCFS. In both these cases, the variation in the plasma density is necessary for the radial localization. In the three-dimensional nonlinear simulations, we have solved a set of fluid equations in a toroidal geometry with both the closed flux region and the SOL. The introduction of the SOL to the twisted tube for the closed flux region, has been a major addition to our 3D code. We find that the turbulent transport in the SOL drops significantly as A is increased, which is consistent with our expectations from the 2D linear code results

  17. ELMs and constraints on the H-mode pedestal: peeling-ballooning stability calculation and comparison with experiment

    International Nuclear Information System (INIS)

    Snyder, P.B.; Ferron, J.R.; Wilson, H.R.

    2004-01-01

    We review and test the peeling-ballooning model for edge localized modes (ELMs) and pedestal constraints, a model based upon theoretical analysis of magnetohydrodynamic (MHD) instabilities that can limit the pedestal height and drive ELMs. A highly efficient MHD stability code, ELITE, is used to calculate quantitative stability constraints on the pedestal, including constraints on the pedestal height. Because of the impact of collisionality on the bootstrap current, these pedestal constraints are dependent on the density and temperature separately, rather than simply on the pressure. ELITE stability calculations are directly compared with experimental data for a series of plasmas in which the density is varied and ELM characteristics change. In addition, a technique is developed whereby peeling-ballooning pedestal constraints are calculated as a function of key equilibrium parameters via ELITE calculations using series of model equilibria. This technique is used to successfully compare the expected pedestal height as a function of density, triangularity and plasma current with experimental data. Furthermore, the technique can be applied for parameter ranges beyond the purview of present experiments, and we present a brief projection of peeling-ballooning pedestal constraints for burning plasma tokamak designs. (author)

  18. Drift-kinetic Alfven modes in high performance tokamaks

    International Nuclear Information System (INIS)

    Jaun, A.; Fasoli, A.F.; Testa, D.; Vaclavik, J.; Villard, L.

    2001-01-01

    The stability of fast-particle driven Alfven eigenmodes is modeled in high performance tokamaks, successively with a conventional shear, an optimized shear and a tight aspect ratio plasma. A large bulk pressure yields global kinetic Alfven eigenmodes that are stabilized by mode conversion in the presence of a divertor. This suggests how conventional reactor scenarii could withstand significant pressure gradients from the fusion products. A large safety factor in the core q 0 >2.5 in deeply shear reversed configurations and a relatively large bulk ion Larmor radius in a low magnetic field can trigger global drift-kinetic Alfven eigenmodes that are unstable in high performance JET, NSTX and ITER plasmas. (author)

  19. Simulations of drift resistive ballooning L-mode turbulence in the edge plasma of the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B. I.; Umansky, M. V.; Nevins, W. M.; Makowski, M. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Boedo, J. A.; Rudakov, D. L. [University of California, San Diego, San Diego, California 92093 (United States); McKee, G. R.; Yan, Z. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Groebner, R. J. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

    2013-05-15

    Results from simulations of electromagnetic drift-resistive ballooning turbulence for tokamak edge turbulence in realistic single-null geometry are reported. The calculations are undertaken with the BOUT three-dimensional fluid code that solves Braginskii-based fluid equations [X. Q. Xu and R. H. Cohen, Contrib. Plasma Phys. 36, 158 (1998)]. The simulation setup models L-mode edge plasma parameters in the actual magnetic geometry of the DIII-D tokamak [J. L. Luxon et al., Fusion Sci. Technol. 48, 807 (2002)]. The computations track the development of drift-resistive ballooning turbulence in the edge region to saturation. Fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes are compared to experimental data near the outer midplane from Langmuir probe and beam-emission-spectroscopy for a few well-characterized L-mode discharges in DIII-D. The simulations are comprised of a suite of runs in which the physics model is varied to include more fluid fields and physics terms. The simulations yield results for fluctuation amplitudes, correlation lengths, particle and energy fluxes, and diffusivities that agree with measurements within an order of magnitude and within factors of 2 or better for some of the data. The agreement of the simulations with the experimental measurements varies with respect to including more physics in the model equations within the suite of models investigated. The simulations show stabilizing effects of sheared E × B poloidal rotation (imposed zonal flow) and of lower edge electron temperature and density.

  20. Stabilization of kinetic internal kink mode by ion diamagnetic effects

    International Nuclear Information System (INIS)

    Naitou, H.; Kuramoto, T.; Kobayashi, T.; Yagi, M.; Tokuda, S.; Matsumoto, T.

    2000-04-01

    Ion diamagnetic effects on the m=1 (poloidal mode number) and n=1 (toroidal mode number) kinetic internal kink mode are studied numerically by the three-field gyro-reduced-MHD code in the cylindrical coordinates, GRM3F-CY. In the derivation of the gryo-reduced-MHD model including the ion diamagnetic effects, finite gyroradius effects of ions are added to the gyrokinetic Poisson equation (quasi-neutral condition) and the convection term of the conservation law of the ion density. It is found that the long wavelength approximation, ksub(perpendicular) ρ ti ti is the thermal ion gyroradius, fails to reproduce the correct dispersion relation; the formulation valid even for ksub(perpendicular) ρ ti >> 1 is necessary. The results of numerical calculation coincide with the theory for |ω *e |+|ω *i | 0 , where the growth rate reduces as the density gradient increases. Here ω *e and ω *i are electron and ion diamagnetic angular frequencies estimated at the rational surface of q=1 (q is a safety factor), respectively, and γ 0 is the growth rate for the uniform density. Very weak instability, however, is observed for |ω *e |+|ω *i | 0 , where the theory predicts the complete stabilization. This residual instability appears since the region with the density gradient is limited in the radial direction and the stabilization by the outgoing drift-wave like mode becomes incomplete. (author)

  1. The stability of internal transport barriers to MHD ballooning modes and drift waves: A formalism for low magnetic shear and for velocity shear

    International Nuclear Information System (INIS)

    Connor, J.W.; Hastie, R.J.; Webster, A.J.; Wilson, H.R.

    2005-01-01

    Tokamak discharges with internal transport barriers (ITBs) provide improved confinement, so it is important to understand their stability properties. The stability to an important class of modes with high wave-numbers perpendicular to the magnetic field, is usually studied with the standard ballooning transformation and eikonal approach. However, ITBs are often characterised by radial q profiles that have regions of negative or low magnetic shear and by radially sheared electric fields. Both these features affect the validity of the standard method. A new approach to calculating stability in these circumstances is developed and applied to ideal MHD ballooning modes and to micro-instabilities responsible for anomalous transport. (author)

  2. Kinetic neoclassical transport in the H-mode pedestal

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, D. J.; Chang, C. S.; Ku, S.; Grierson, B. A. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08540 (United States); Burrell, K. H.; Grassie, J. S. de [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

    2014-07-15

    Multi-species kinetic neoclassical transport through the QH-mode pedestal and scrape-off layer on DIII-D is calculated using XGC0, a 5D full-f particle-in-cell drift-kinetic solver with self-consistent neutral recycling and sheath potentials. Quantitative agreement between the flux-driven simulation and the experimental electron density, impurity density, and orthogonal measurements of impurity temperature and flow profiles is achieved by adding random-walk particle diffusion to the guiding-center drift motion. The radial electric field (E{sub r}) that maintains ambipolar transport across flux surfaces and to the wall is computed self-consistently on closed and open magnetic field lines and is in excellent agreement with experiment. The E{sub r} inside the separatrix is the unique solution that balances the outward flux of thermal tail deuterium ions against the outward neoclassical electron flux and inward pinch of impurity and colder deuterium ions. Particle transport in the pedestal is primarily due to anomalous transport, while the ion heat and momentum transport are primarily due to the neoclassical transport. The full-f treatment quantifies the non-Maxwellian energy distributions that describe a number of experimental observations in low-collisionallity pedestals on DIII-D, including intrinsic co-I{sub p} parallel flows in the pedestal, ion temperature anisotropy, and large impurity temperatures in the scrape-off layer.

  3. Marginal Stability Boundaries for Infinite-n Ballooning Modes in a Quasi-axisymmetric Stellarator

    International Nuclear Information System (INIS)

    Hudson, S.R.; Hegna, C.C.

    2003-01-01

    A method for computing the ideal-MHD stability boundaries in three-dimensional equilibria is employed. Following Hegna and Nakajima [Phys. Plasmas 5 (May 1998) 1336], a two-dimensional family of equilibria are constructed by perturbing the pressure and rotational-transform profiles in the vicinity of a flux surface for a given stellarator equilibrium. The perturbations are constrained to preserve the magnetohydrodynamic equilibrium condition. For each perturbed equilibrium, the infinite-n ballooning stability is calculated. Marginal stability diagrams are thus constructed that are analogous to (s; a) diagrams for axisymmetric configurations. A quasi-axisymmetric stellarator is considered. Calculations of stability boundaries generally show regions of instability can occur for either sign of the average magnetic shear. Additionally, regions of second-stability are present

  4. MHD Ballooning Instability in the Plasma Sheet

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Zaharia, S.

    2003-01-01

    Based on the ideal-MHD model the stability of ballooning modes is investigated by employing realistic 3D magnetospheric equilibria, in particular for the substorm growth phase. Previous MHD ballooning stability calculations making use of approximations on the plasma compressibility can give rise to erroneous conclusions. Our results show that without making approximations on the plasma compressibility the MHD ballooning modes are unstable for the entire plasma sheet where beta (sub)eq is greater than or equal to 1, and the most unstable modes are located in the strong cross-tail current sheet region in the near-Earth plasma sheet, which maps to the initial brightening location of the breakup arc in the ionosphere. However, the MHD beq threshold is too low in comparison with observations by AMPTE/CCE at X = -(8 - 9)R(sub)E, which show that a low-frequency instability is excited only when beq increases over 50. The difficulty is mitigated by considering the kinetic effects of ion gyrorad ii and trapped electron dynamics, which can greatly increase the stabilizing effects of field line tension and thus enhance the beta(sub)eq threshold [Cheng and Lui, 1998]. The consequence is to reduce the equatorial region of the unstable ballooning modes to the strong cross-tail current sheet region where the free energy associated with the plasma pressure gradient and magnetic field curvature is maximum

  5. Ballooning-mirror instability and internally driven Pc 4--5 wave events

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Qian, Q.; Takahashi, K.; Lui, A.T.Y.

    1994-03-01

    A kinetic-MHD field-aligned eigenmode stability analysis of low frequency ballooning-mirror instabilities has been performed for anisotropic pressure plasma sin the magnetosphere. The ballooning mode is mainly a transverse wave driven unstable by pressure gradient in the bad curvature region. The mirror mode with a dominant compressional magnetic field perturbation is excited when the product of plasma beta and pressure anisotropy (P perpendicular /P parallel > 1) is large. From the AMPTE/CCE particle and magnetic field data observed during Pc 4--5 wave events the authors compute the ballooning-mirror instability parameters and perform a correlation study with the theoretical instability threshold. They find that compressional Pc 5 waves approximately satisfy the ballooning-mirror instability condition, and transverse Pc 4--5 waves are probably related to resonant ballooning instabilities with small pressure anisotropy

  6. Omega-mode perturbation theory and reactor kinetics for analyzing accelerator-driven subcritical systems

    International Nuclear Information System (INIS)

    Ren-Tai, Chiang

    2003-01-01

    An ω-mode first-order perturbation theory is developed for analyzing the time- and space-dependent neutron behavior in Accelerator-Driven Subcritical Systems (ADSS). The generalized point-kinetics equations are systematically derived using the ω-mode first-order perturbation theory and Fredholm Alternative Theorem. Seven sets of the ω-mode eigenvalues exist with using six groups of delayed neutrons and all ω eigenvalues are negative in ADSS. Seven ω-mode adjoint and forward eigenfunctions are employed to form the point-kinetic parameters. The neutron flux is expressed as a linear combination of the products of seven ω-eigenvalue-mode shape functions and their corresponding time functions up to the first order terms, and the lowest negative ω-eigenvalue mode is the dominant mode. (author)

  7. Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Eldon, D., E-mail: deldon@princeton.edu [University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0964 (United States); Princeton University, Princeton, New Jersey 08543 (United States); Boivin, R. L.; Groebner, R. J.; Osborne, T. H.; Snyder, P. B.; Turnbull, A. D.; Burrell, K. H. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Tynan, G. R.; Boedo, J. A. [University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0964 (United States); Kolemen, E. [Princeton University, Princeton, New Jersey 08543 (United States); Schmitz, L. [University of California Los Angeles, Los Angeles, California 90095-7099 (United States); Wilson, H. R. [University of York, Heslington, York YO10 5DD (United Kingdom)

    2015-05-15

    The H-mode transport barrier allows confinement of roughly twice as much energy as in an L-mode plasma. Termination of H-mode necessarily requires release of this energy, and the timescale of that release is of critical importance for the lifetimes of plasma facing components in next step tokamaks such as ITER. H-L transition sequences in modern tokamaks often begin with a transient outburst which appears to be superficially similar to and has sometimes been referred to as a type-I edge localized mode (ELM). Type-I ELMs have been shown to be consistent with ideal peeling ballooning instability and are characterized by significant (up to ∼50%) reduction of pedestal height on short (∼1 ms) timescales. Knowing whether or not this type of instability is present during H-L back transitions will be important of planning for plasma ramp-down in ITER. This paper presents tests of pre-transition experimental data against ideal peeling-ballooning stability calculations with the ELITE code and supports those results with secondary experiments that together show that the transient associated with the H-L transition is not triggered by the same physics as are type-I ELMs.

  8. Kelvin-Helmholtz instability and kinetic internal kink modes in tokamaks

    International Nuclear Information System (INIS)

    Naitou, H.

    2002-01-01

    The m=1 and n=1 kinetic internal kink (KIK) mode with a nonuniform density profile is studied by the cylindrical version of the gyro-reduced-MHD code which is one of the extended MHD codes being able to treat the physics beyond resistive MHD. Electron inertia and electron finite temperature effects are crucial. The linear mode structure of KIK mode includes the sheared poloidal flow with m=1, which excites the vortexes due to the Kelvin-Helmholtz (K-H) instability. We have found that there is a strong coupling between the KIK mode and the K-H mode even in the early nonlinear stage of KIK instability in which the width of the m=1 magnetic island is sufficiently small. (author)

  9. Inflation and deflation timing of the AutoCAT 2 WAVE intra-aortic balloon pump using the autoPilot mode in a clinical setting.

    Science.gov (United States)

    Bakker, E W M; Visser, K; van der Wal, A; Kuiper, M A; Koopmans, M; Breedveld, R

    2012-09-01

    The primary goal of this observational clinical study was to register the occurrence of incorrect inflation and deflation timing of an intra-aortic balloon pump in autoPilot mode. The secondary goal was to identify possible causes of incorrect timing. During IABP assistance of 60 patients, every four hours a strip was printed with the IABP frequency set to 1:2. Strips were examined for timing discrepancies beyond 40 ms from the dicrotic notch (inflation) and the end of the diastolic phase (deflation). In this way, 320 printed strips were examined. A total of 52 strips (16%) showed incorrect timing. On 24 of these strips, the incorrect timing was called incidental, as it showed on only one or a few beats. The other 28 cases of erroneous timing were called consistent, as more than 50% of the beats on the strip showed incorrect timing. We observed arrhythmia in 69% of all cases of incorrect timing. When timing was correct, arrhythmia was found on 13 (5%) of 268 strips. A poor quality electrocardiograph (ECG) signal showed on 37% of all strips with incorrect timing and 11% of all strips with proper timing. We conclude that inflation and deflation timing of the IABP is not always correct when using the autoPilot mode. The quality of the ECG input signal and the occurrence of arrhythmia appear to be related to erroneous timing. Switching from autoPilot mode to operator mode may not always prevent incorrect timing.

  10. Nuclear matter kinetic coefficients and damping of finite nuclear collective modes

    International Nuclear Information System (INIS)

    Toledo Piza, A.F.R. de.

    1986-06-01

    By carrying the general description of one-body observables beyond the mean-field approximation, those correlation terms responsible for Kinetic phenomena and those involved in the renormalization of the G-matrix mean-field in finite nuclei are identified. A Kinetic equation for the one-body density is obtained. Estimates for transport coefficients and for the damping of zero sound are obtained which point to the inadequacy of hydrodynamical descriptions of collective nuclear modes and indicate that collisional damping in large nuclei may account for one or a few tenths of the observed widths. (S.D.) [pt

  11. Derivation of regularized Grad's moment system from kinetic equations: modes, ghosts and non-Markov fluxes

    Science.gov (United States)

    Karlin, Ilya

    2018-04-01

    Derivation of the dynamic correction to Grad's moment system from kinetic equations (regularized Grad's 13 moment system, or R13) is revisited. The R13 distribution function is found as a superposition of eight modes. Three primary modes, known from the previous derivation (Karlin et al. 1998 Phys. Rev. E 57, 1668-1672. (doi:10.1103/PhysRevE.57.1668)), are extended into the nonlinear parameter domain. Three essentially nonlinear modes are identified, and two ghost modes which do not contribute to the R13 fluxes are revealed. The eight-mode structure of the R13 distribution function implies partition of R13 fluxes into two types of contributions: dissipative fluxes (both linear and nonlinear) and nonlinear streamline convective fluxes. Physical interpretation of the latter non-dissipative and non-local in time effect is discussed. A non-perturbative R13-type solution is demonstrated for a simple Lorentz scattering kinetic model. The results of this study clarify the intrinsic structure of the R13 system. This article is part of the theme issue `Hilbert's sixth problem'.

  12. Balloon sinuplasty

    OpenAIRE

    Ahmad, Zahoor

    2010-01-01

    Balloon sinuplasty is a technique in endoscopic sinus surgery that involves minimally invasive procedures to dilate the obstructed or stenosed anatomical sinus pathways. Procedure is derived from the well-recognized techinique of angioplasty. This article highlights the procedural methods with review of literature and my personal experience in balloon sinupalsty.

  13. Kinetic Alfven Waves at the Magnetopause-Mode Conversion, Transport and Formation of LLBL; TOPICAL

    International Nuclear Information System (INIS)

    Jay R. Johnson; C.Z. Cheng

    2002-01-01

    At the magnetopause, large amplitude, low-frequency (ULF), transverse MHD waves are nearly always observed. These waves likely result from mode conversion of compressional MHD waves observed in the magnetosheath to kinetic Alfven waves at the magnetopause where there is a steep gradient in the Alfven velocity[Johnson and Cheng, Geophys. Res. Lett. 24 (1997) 1423]. The mode-conversion process can explain the following wave observations typically found during satellite crossings of the magnetopause: (1) a dramatic change in wave polarization from compressional in the magnetosheath to transverse at the magnetopause, (2) an amplification of wave amplitude at the magnetopause, (3) a change in Poynting flux from cross-field in the magnetosheath to field-aligned at the magnetopause, and (4) a steepening in the wave power spectrum at the magnetopause. We examine magnetic field data from a set of ISEE1, ISEE2, and WIND magnetopause crossings and compare with the predictions of theoretical wave solutions based on the kinetic-fluid model with particular attention to the role of magnetic field rotation across the magnetopause. The results of the study suggest a good qualitative agreement between the observations and the theory of mode conversion to kinetic Alfven waves. Because mode-converted kinetic Alfven waves readily decouple particles from the magnetic field lines, efficient quasilinear transport (D(approx) 109m2/s) can occur. Moreover, if the wave amplitude is sufficiently large (Bwave/B0 and gt; 0.2) stochastic particle transport also occurs. This wave-induced transport can lead to significant heating and particle entry into the low latitude boundary layer across closed field lines.At the magnetopause, large amplitude, low-frequency (ULF), transverse MHD waves are nearly always observed. These waves likely result from mode conversion of compressional MHD waves observed in the magnetosheath to kinetic Alfven waves at the magnetopause where there is a steep gradient in

  14. Signatures of mode conversion and kinetic Alfven waves at the magnetopause

    International Nuclear Information System (INIS)

    Johnson, Jay R.; Cheng, C. Z.

    2000-01-01

    It has been suggested that resonant mode conversion of compressional MHD waves into kinetic Alfven waves at the magnetopause can explain the abrupt transition in wave polarization from compressional to transverse commonly observed during magnetopause crossings. The authors analyze magnetic field data for magnetopause crossings as a function of magnetic shear angle (defined as the angle between the magnetic fields in the magnetosheath and magnetosphere) and compare with the theory of resonant mode conversion. The data suggest that amplification in the transverse magnetic field component at the magnetopause is not significant up to a threshold magnetic shear angle. Above the threshold angle significant amplification results, but with weak dependence on magnetic shear angle. Waves with higher frequency are less amplified and have a higher threshold angle. These observations are qualitatively consistent with theoretical results obtained from the kinetic-fluid wave equations

  15. The Kinetic of Biogas Production Rate from Cattle Manure in Batch Mode

    OpenAIRE

    Budiyono; I N. Widiasa; S. Johari; Sunarso

    2010-01-01

    In this study, the kinetic of biogas production was studied by performing a series laboratory experiment using rumen fluid of animal ruminant as inoculums. Cattle manure as substrate was inoculated by rumen fluid to the anaerobic biodigester. Laboratory experiments using 400 ml biodigester were performed in batch operation mode. Given 100 grams of fresh cattle manure was fed to each biodigester and mixed with rumen fluid by manure : rumen weight ratio of 1:1 (MR11). The operating temperatures...

  16. Effects of isotropic alpha populations on tokamak ballooning stability

    International Nuclear Information System (INIS)

    Spong, D.A.; Sigmar, D.J.; Tsang, K.T.; Ramos, J.J.; Hastings, D.E.; Cooper, W.A.

    1986-12-01

    Fusion product alpha populations can significantly influence tokamak stability due to coupling between the trapped alpha precessional drift and the kinetic ballooning mode frequency. Careful, quantitative evaluations of these effects are necessary in burning plasma devices such as the Tokamak Fusion Test Reactor and the Joint European Torus, and we have continued systematic development of such a kinetic stability model. In this model we have considered a range of different forms for the alpha distribution function and the tokamak equilibrium. Both Maxwellian and slowing-down models have been used for the alpha energy dependence while deeply trapped and, more recently, isotropic pitch angle dependences have been examined

  17. Theory of ballooning-mirror instabilities for anisotropic pressure plasmas in the magnetosphere

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Qian, Q.

    1993-09-01

    This paper deals with a kinetic-MHD eigenmode stability analysis of low frequency ballooning-mirror instabilities for anisotropic pressure plasmas in the magnetosphere. The ballooning mode is a dominant transverse wave driven unstable by pressure gradient in the bad curvature region. The mirror mode with a dominant compressional magnetic field perturbation is excited when the product of plasma beta and pressure anisotropy is large. The field-aligned eigenmode equations take into account the coupling of the transverse and compressional components of the perturbed magnetic field and describe the coupled ballooning-mirror mode. Because the energetic trapped ions precess very rapidly across the rvec B field, their motion becomes very rigid with respect to low frequency MHD perturbations with symmetric structure of parallel perturbed magnetic field δB parallel and electrostatic potential Φ along the north-south ambient magnetic field, and the symmetric ballooning-mirror mode is shown to be stable. On the other hand, the ballooning-mirror mode with antisymmetric δB parallel , and Φ structure along the north-south ambient magnetic field is only weakly influenced by energetic trapped particle kinetic effects due to rapid trapped particle bounce motion and has the lowest instability threshold determined by MHD theory. With large plasma beta (β parallel ≥ O(1)) and pressure anisotropy (P perpendicular /P parallel > 1) at equator the antisymmetric ballooning-mirror mode structures resemble the field-aligned wave structures of the multisatellite observations of a long lasting compressional Pc 5 wave event during November 14--15, 1979 [Takahashi et al.]. The study provides the theoretical basis for identifying the internal excitation mechanism of ULF (Pc 4-5) waves by comparing the plasma stability parameters computed from the satellite particle data with the theoretical values

  18. Unconventional ballooning structures for toroidal drift waves

    International Nuclear Information System (INIS)

    Xie, Hua-sheng; Xiao, Yong

    2015-01-01

    With strong gradients in the pedestal of high confinement mode (H-mode) fusion plasmas, gyrokinetic simulations are carried out for the trapped electron and ion temperature gradient modes. A broad class of unconventional mode structures is found to localize at arbitrary poloidal positions or with multiple peaks. It is found that these unconventional ballooning structures are associated with different eigen states for the most unstable mode. At weak gradient (low confinement mode or L-mode), the most unstable mode is usually in the ground eigen state, which corresponds to a conventional ballooning mode structure peaking in the outboard mid-plane of tokamaks. However, at strong gradient (H-mode), the most unstable mode is usually not the ground eigen state and the ballooning mode structure becomes unconventional. This result implies that the pedestal of H-mode could have better confinement than L-mode

  19. Ballooning stable high beta tokamak equilibria

    International Nuclear Information System (INIS)

    Tuda, Takashi; Azumi, Masafumi; Kurita, Gen-ichi; Takizuka, Tomonori; Takeda, Tatsuoki

    1981-04-01

    The second stable regime of ballooning modes is numerically studied by using the two-dimensional tokamak transport code with the ballooning stability code. Using the simple FCT heating scheme, we find that the plasma can locally enter this second stable regime. And we obtained equilibria with fairly high beta (β -- 23%) stable against ballooning modes in a whole plasma region, by taking into account of finite thermal diffusion due to unstable ballooning modes. These results show that a tokamak fusion reactor can operate in a high beta state, which is economically favourable. (author)

  20. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    Science.gov (United States)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  1. Kelvin-Helmholtz instability and kinetic internal kink modes in tokamaks

    International Nuclear Information System (INIS)

    Naitou, H.; Kobayashi, T.; Yagi, M.; Matsumoto, T.; Tokuda, S.; Kishimoto, Y.

    2003-01-01

    The m=1 (poloidal mode number) and n=1 (toroidal mode number) kinetic internal kink (KIK) mode in the presence of a density gradient is studied with the cylindrical version of the gyro-reduced MHD code, which is one of the extended MHD codes being able to treat the physics beyond resistive MHD. Electron inertia and electron finite temperature effects are included. The unstable KIK mode is observed in the parameter range in which the linear theory predicts complete stabilization due to the electron diamagnetic effect. The electrostatic potential profile in the linear stage of the KIK instability has the sheared poloidal flow with the m=1 mode structure. The vortexes are generated due to the Kelvin-Helmholtz (K-H) instability. The KIK is stabilized when the vortexes are formed, but it is destabilized again as the vortexes diminish due to the charge neutralizing electron motion along the magnetic field. These phenomena are observed in the early nonlinear stage of the KIK instability in which the width of the m=1 magnetic island is sufficiently small compared with the radial extent of the vortexes. The strong coupling between the vortexes and the KIK instability can be one of the candidates explaining the sudden onset of the sawtooth crash. (author)

  2. Alpha particle effects on MHD ballooning

    International Nuclear Information System (INIS)

    1991-01-01

    During the period, as the first step towards the goal of detail understanding of the effects of alpha particle on MHD Ballooning Modes, a new numerical approach to investigate the stability of low-frequency fluctuations in high temperature tokamaks was developed by solving the gyrokinetic equations for the ion and electron directly as an initial value problem. The advantage of this approach is the inclusion of many important kinetic features of the problem without approximations and computationally more economical than particle-pushing simulation. The ion-temperature-gradient-mode was investigated to benchmark this new simulation technique. Previous results in literature were recovered. Both the adiabatic electron model and the full drift-kinetic electron model are studied. Numerical result shows that the full drift-kinetic electron model is more unstable. The development of subcycling technique to handle the fast electron bounce time is particularly significant to apply this new approach to the alpha particle problem since alpha particle bounce frequency is also significantly higher than the mode frequency. This new numerical technique will be the basis of future study of the microstability in high temperature tokamaks with alpha particles (or any energetic species). 15 refs., 13 figs

  3. A new kinetic description for turbulent collisions including mode-coupling

    International Nuclear Information System (INIS)

    Misguich, J.H.; Tchen, C.M.

    1982-07-01

    The usual introduction of higher-order mode-coupling terms in the description of turbulent collisions beyond usual Renormalized Quasi-Linear approximation (RQL) is briefly analyzed. Here new results are derived in the framework of the general kinetic theory, and the equivalence is proved with the long time limit of simple results deduced from the Vlasov equation. The correction to the RQL turbulent collision term is analyzed and a new approximation is proposed. Turbulent collisions are also described by perturbation around the Lagrangian autocorrelation of fluctuating fields. For an homogeneous turbulence, however, the asymptotic integral of this Lagrangian autocorrelation vanishes identically, similarly to what occurs in Brownian motion. For inhomogeneous turbulence this method can nevertheless be used, and higher-order mode-coupling terms can be interpreted as a shielding of elementary Lagrangian turbulent collisions

  4. Assay of phospholipases A2 and their inhibitors by kinetic analysis in the scooting mode

    Directory of Open Access Journals (Sweden)

    Mahendra Kumar Jain

    1992-01-01

    Full Text Available Several cellular processes are regulated by interfacial catalysis on biomembrane surfaces. Phospholipases A2 (PLA2 are interesting not only as prototypes for interfacial catalysis, but also because they mobilize precursors for the biosynthesis of eicosanoids and platelet activating factor, and these agents ultimately control a wide range of secretory and inflammatory processes. Since PLA2 carry out their catalytic function at membrane surfaces, the kinetics of these enzymes depends on what the enzyme ‘sees’ at the interface, and thus the observed rate is profoundly influenced by the organization and dynamics of the lipidwater interface (‘quality of the interface’. In this review we elaborate the advantages of monitoring interfacial catalysis in the scooting mode, that is, under the conditions where the enzyme remains bound to vesicles for several thousand catalytic turnover cycles. Such a highly processive catalytic turnover in the scooting mode is useful for a rigorous and quantitative characterization of the kinetics of interfacial catalysis. This analysis is now extended to provide insights into designing strategy for PLA2 assays and screens for their inhibitors.

  5. Kinetic study of the sausage mode of a resistive instability of a relativistic electron beam

    International Nuclear Information System (INIS)

    Gureev, K.G.; Zolotarev, V.O.; Stolbetsov, S.D.

    1984-01-01

    The nonlinear problem of the growth of the sausage mode of the resistive instability of a relativistic electron beam propagating without collisions through a tenuous plasma is solved. The plasma conductivity is assumed to be high, so that the wave phase velocity is low in comparison with the velocity of light. A kinetic approach is taken to the description of the beam. A numerical solution of the problem shows that this instability occurs in a cold, uniform beam. In the nonlinear stage of the instability the beam goes through states with a hollow structure. Suppression of the instability is found for a beam with a Bennett distribution function. The stabilization results from phase mixing of the beam particles

  6. Identification of low-frequency kinetic wave modes in the Earth's ion foreshock

    Directory of Open Access Journals (Sweden)

    X. Blanco-Cano

    1997-03-01

    Full Text Available In this work we use ion and magnetic field data from the AMPTE-UKS mission to study the characteristics of low frequency (ωr « Ωp waves observed upstream of the Earth's bow shock. We test the application of various plasma-field correlations and magnetic ratios derived from linear Vlasov theory to identify the modes in this region. We evaluate (for a parameter space consistent with the ion foreshock the Alfvén ratio, the parallel compressibility, the cross-helicity, the noncoplanar ratio, the magnetic compression and the polarization for the two kinetic instabilities that can be generated in the foreshock by the interaction of hot diffuse ions with the solar wind: the left-hand resonant and the right-hand resonant ion beam instabilities. Comparison of these quantities with the observed plasma-field correlations and various magnetic properties of the waves observed during 10 intervals on 30 October 1984, where the waves are associated with diffuse ions, allows us to identify regions with Alfvénic waves and regions where the predominant mode is the right-hand resonant instability. In all the cases the waves are transverse, propagating at angles ≤ 33° and are elliptically polarized. Our results suggest that while the observed Alfvén waves are generated locally by hot diffuse ions, the right-handed waves may result from the superposition of waves generated by two different types of beam distribution (i.e. cold beam and diffuse ions. Even when there was good agreement between the values of observed transport ratios and the values given by the theory, some discrepancies were found. This shows that the observed waves are different from the theoretical modes and that mode identification based only on polarization quantities does not give a complete picture of the waves' characteristics and can lead to mode identification of waves whose polarization may agree with theoretical predictions even when other properties can diverge from those of the

  7. Identification of low-frequency kinetic wave modes in the Earth's ion foreshock

    Directory of Open Access Journals (Sweden)

    X. Blanco-Cano

    Full Text Available In this work we use ion and magnetic field data from the AMPTE-UKS mission to study the characteristics of low frequency (ωr « Ωp waves observed upstream of the Earth's bow shock. We test the application of various plasma-field correlations and magnetic ratios derived from linear Vlasov theory to identify the modes in this region. We evaluate (for a parameter space consistent with the ion foreshock the Alfvén ratio, the parallel compressibility, the cross-helicity, the noncoplanar ratio, the magnetic compression and the polarization for the two kinetic instabilities that can be generated in the foreshock by the interaction of hot diffuse ions with the solar wind: the left-hand resonant and the right-hand resonant ion beam instabilities. Comparison of these quantities with the observed plasma-field correlations and various magnetic properties of the waves observed during 10 intervals on 30 October 1984, where the waves are associated with diffuse ions, allows us to identify regions with Alfvénic waves and regions where the predominant mode is the right-hand resonant instability. In all the cases the waves are transverse, propagating at angles ≤ 33° and are elliptically polarized. Our results suggest that while the observed Alfvén waves are generated locally by hot diffuse ions, the right-handed waves may result from the superposition of waves generated by two different types of beam distribution (i.e. cold beam and diffuse ions. Even when there was good agreement between the values of observed transport ratios and the values given by the theory, some discrepancies were found. This shows that the observed waves are different from the theoretical modes and that mode identification based only on polarization quantities does not give a complete picture of the waves' characteristics and can lead to mode identification of waves whose polarization may agree with theoretical predictions even when

  8. Fasting and meal-suppressed ghrelin levels before and after intragastric balloons and balloon-induced weight loss

    NARCIS (Netherlands)

    Mathus-Vliegen, E. M. H.; Eichenberger, R. I.

    2014-01-01

    Intragastric balloons may be an option for obese patients with weight loss failure. Its mode of action remains enigmatic. We hypothesised depressed fasting ghrelin concentrations and enhanced meal suppression of ghrelin secretion by the gastric fundus through balloon contact and balloon-induced

  9. Balloon pulmonary valvotomy – Not just a simple balloon dilatation

    Directory of Open Access Journals (Sweden)

    Subhendu Mohanty

    2014-07-01

    Full Text Available Balloon pulmonary valvotomy is the preferred mode of treatment in patients with isolated pulmonary valvar stenosis and has shown good long term results. It is generally considered a safe procedure with few complications. There have been however, case reports of potentially fatal acute severe pulmonary edema occurring after the procedure in some patients. The cause of this complication and its pathophysiology is still not clear. Its occurrence is also infrequent with less than 5 cases reported till now. We report a case of pulmonary valvar stenosis which developed acute severe refractory pulmonary edema immediately after balloon pulmonary valvotomy.

  10. Non-dissipative kinetic simulation and analytical solution of three-mode equations of ion temperature gradient instability

    International Nuclear Information System (INIS)

    Watanabe, T.-H.; Sugama, H.; Sato, T.

    1999-12-01

    A non-dissipative drift kinetic simulation scheme, which rigorously satisfies the time-reversibility, is applied to the three-mode coupling problem of the ion temperature gradient (ITG) instability. It is found from the simulation that the three-mode ITG system repeats growth and decay with a period which shows a logarithmic divergence for infinitesimal initial perturbations. Accordingly, time average of the mode amplitude vanishes, as the initial amplitude approaches to zero. An exact solution is analytically given for a class of initial conditions. An excellent agreement is confirmed between the analytical solution and numerical results. The results obtained here provide a useful reference for basic benchmarking of theories and simulation of the ITG modes. (author)

  11. Energy from solar balloons

    Energy Technology Data Exchange (ETDEWEB)

    Grena, Roberto [C. R. Casaccia, via Anguillarese 301, 00123 Roma (Italy)

    2010-04-15

    Solar balloons are hot air balloons in which the air is heated directly by the sun, by means of a black absorber. The lift force of a tethered solar balloon can be used to produce energy by activating a generator during the ascending motion of the balloon. The hot air is then discharged when the balloon reaches a predefined maximum height. A preliminary study is presented, along with an efficiency estimation and some considerations on possible realistic configurations. (author)

  12. Effects of alpha populations on tokamak ballooning stability

    International Nuclear Information System (INIS)

    Spong, D.A.; Sigmar, D.J.; Tsang, K.T.; Ramos, J.J.; Hastings, D.E.; Cooper, W.A.

    1986-01-01

    Fusion product alpha populations can significantly influence tokamak stability due to coupling between the trapped alpha precessional drift and the kinetic ballooning mode frequency. This effect is of particular importance in parameter regimes where the alpha pressure gradient begins to constitute a sizable fraction of the thermal plasma pressure gradient. Careful, quantitative evaluations of these effects are necessary in burning plasma devices such as the Tokamak Fusion Test Reactor and the Joint European Torus, and we have continued systematic development of such a kinetic stability model. In this model we have considered a range of different forms for the alpha distribution function and the tokamak equilibrium. Both Maxwellian and slowing-down models have been used for the alpha energy dependence while deeply trapped and, more recently, isotropic pitch angle dependence have been examined

  13. Experimental validation of an analytical kinetic model for edge-localized modes in JET-ITER-like wall

    Science.gov (United States)

    Guillemaut, C.; Metzger, C.; Moulton, D.; Heinola, K.; O’Mullane, M.; Balboa, I.; Boom, J.; Matthews, G. F.; Silburn, S.; Solano, E. R.; contributors, JET

    2018-06-01

    The design and operation of future fusion devices relying on H-mode plasmas requires reliable modelling of edge-localized modes (ELMs) for precise prediction of divertor target conditions. An extensive experimental validation of simple analytical predictions of the time evolution of target plasma loads during ELMs has been carried out here in more than 70 JET-ITER-like wall H-mode experiments with a wide range of conditions. Comparisons of these analytical predictions with diagnostic measurements of target ion flux density, power density, impact energy and electron temperature during ELMs are presented in this paper and show excellent agreement. The analytical predictions tested here are made with the ‘free-streaming’ kinetic model (FSM) which describes ELMs as a quasi-neutral plasma bunch expanding along the magnetic field lines into the Scrape-Off Layer without collisions. Consequences of the FSM on energy reflection and deposition on divertor targets during ELMs are also discussed.

  14. Ballooning behavior in the golden orbweb spider Nephilapilipes (Araneae: Nephilidae

    Directory of Open Access Journals (Sweden)

    Vanessa M.J. Lee

    2015-01-01

    Full Text Available Ballooning, a mode of aerial dispersal in spiders, is an innate behavior that requires appropriate physiological and meteorological conditions. Although only rarely reported in the golden orbweb spiders, family Nephilidae, the large geographic distributions of most nephilids—in particular of Nephila species—would imply that these spiders likely routinely disperse by ballooning in spite of giant female sizes. Here we study ballooning behavior in the golden orbweb spider Nephila pilipes (Fabricius, 1793. Specifically, we test for the propensity of spiderlings to deploy ballooning as a dispersal mechanism. We subjected a total of 59 first-instar spiderlings to a wind experiment at two wind speeds (2.17 ± 0.02 m s-1 and 3.17 ± 0.02 m s-1 under laboratory conditions. Under an average wind speed of 3.17 m s-1, none of the spiderlings exhibited pre-ballooning or ballooning behavior. However, at an average wind speed of 2.17 m s-1, 53 (89.8% spiderlings showed pre-ballooning behavior, and 17 (32.1% of the pre-ballooners ultimately ballooned. Our results concur with prior reports on spiderlings of other families that pre-ballooning behavior is a requirement for ballooning to occur. Furthermore, although we cannot rule out other dispersal mechanisms such as synanthropic spread, our findings suggest that the widespread N. pilipes uses ballooning to colonize remote oceanic islands.

  15. Ballooning stability of JET discharges

    International Nuclear Information System (INIS)

    Huysmans, G.T.A.; Goedbloed, J.P.; Galvao, R.M.O.; Lazzaro, E.; Smeulders, P.

    1989-01-01

    Conditions under which ballooning modes are expected to be excited have recently been obtained in two different types of discharges in JET. In the first type, extremely large pressure gradients have been produced in the plasma core through pellet injections in the current rise phase followed by strong additional heating. In the second type, the total pressure of the discharge is approaching the Troyon limit. The stability of these discharges with respect to the ideal MHD ballooning modes has been studied with the stability code HBT. The equilibria are reconstructed with the IDENTC code using the external magnetic measurements and the experimental pressure profile. The results show that the evaluated high beta discharge is unstable in the central region of the plasma. This instability is related to the low shear and not to a large pressure gradient, as expected at the Troyon limit. In the pellet discharges the regions with the large pressure gradients are unstable to ballooning modes at the time of the beta decay, which ends the period of enhanced performance. The maximum pressure gradient in these discharges is limited by the boundary of the first region of stability. The observed phenomena at the beta decay are similar to those observed at the beta limit in DIII-D and TFTR. (author)

  16. Kinetic equilibrium reconstruction for the NBI- and ICRH-heated H-mode plasma on EAST tokamak

    Science.gov (United States)

    Zhen, ZHENG; Nong, XIANG; Jiale, CHEN; Siye, DING; Hongfei, DU; Guoqiang, LI; Yifeng, WANG; Haiqing, LIU; Yingying, LI; Bo, LYU; Qing, ZANG

    2018-04-01

    The equilibrium reconstruction is important to study the tokamak plasma physical processes. To analyze the contribution of fast ions to the equilibrium, the kinetic equilibria at two time-slices in a typical H-mode discharge with different auxiliary heatings are reconstructed by using magnetic diagnostics, kinetic diagnostics and TRANSP code. It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core plasma due to the neutral beam injection power is primarily deposited in the core region. The fast-ion current contributes mainly in the core region while contributes little to the pedestal current. A steep pressure gradient in the pedestal is observed which gives rise to a strong edge current. It is proved that the fast ion effects cannot be ignored and should be considered in the future study of EAST.

  17. Influence of the evaporation rate and the evaporation mode on the hydrogen sorption kinetics of air-exposed magnesium films

    International Nuclear Information System (INIS)

    Leon, A.; Knystautas, E.J.; Huot, J.; Schulz, R.

    2006-01-01

    It has been shown that the hydrogen sorption properties of air-exposed magnesium films are influenced by the deposition parameters such as the evaporation rate or the evaporation mode used during their preparation. As the evaporation rate increases, the structure of the film tends to be highly oriented along the [002] direction and the kinetics of hydrogen absorption and desorption are faster. Moreover, the hydrogen sorption kinetics of magnesium films prepared with an electron beam source under a high vacuum are faster by almost a factor of two compared to those prepared using resistive heating under low vacuum. These two parameters reduce drastically the activation and the incubation period during hydrogen absorption and desorption, respectively

  18. Analyses of kinetic glass transition in short-range attractive colloids based on time-convolutionless mode-coupling theory.

    Science.gov (United States)

    Narumi, Takayuki; Tokuyama, Michio

    2017-03-01

    For short-range attractive colloids, the phase diagram of the kinetic glass transition is studied by time-convolutionless mode-coupling theory (TMCT). Using numerical calculations, TMCT is shown to recover all the remarkable features predicted by the mode-coupling theory for attractive colloids: the glass-liquid-glass reentrant, the glass-glass transition, and the higher-order singularities. It is also demonstrated through the comparisons with the results of molecular dynamics for the binary attractive colloids that TMCT improves the critical values of the volume fraction. In addition, a schematic model of three control parameters is investigated analytically. It is thus confirmed that TMCT can describe the glass-glass transition and higher-order singularities even in such a schematic model.

  19. Spectrum of ballooning instabilities in a stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, W A [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP); Singleton, D B [Australian National Univ., ANU Supercomputing Facility, Canberra (Australia); Dewar, R L [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1995-08-01

    The recent revival of interest in the application of the `ballooning formalism` to low-frequency plasma instabilities has prompted a comparison of the Wentzel-Brillouin-Kramers (WKB) ballooning approximation with an (in principle) exact normal mode calculation for a three-dimensional plasma equilibrium. Semiclassical quantization, using the ideal magnetohydrodynamic (MHD) ballooning eigenvalue to provide a local dispersion relation, is applied to a ten-field period stellarator test case. Excellent qualitative agreement, and good quantitative agreement is found with predictions from the TERPSICHORE code for toroidal mode numbers from 1 to 14 and radial mode numbers from 0 to 2. The continuum bands predicted from three-dimensional WKB theory are too narrow to resolve. (author) 3 figs., 24 refs.

  20. Spectrum of ballooning instabilities in a stellarator

    International Nuclear Information System (INIS)

    Cooper, W.A.; Singleton, D.B.; Dewar, R.L.

    1995-08-01

    The recent revival of interest in the application of the 'ballooning formalism' to low-frequency plasma instabilities has prompted a comparison of the Wentzel-Brillouin-Kramers (WKB) ballooning approximation with an (in principle) exact normal mode calculation for a three-dimensional plasma equilibrium. Semiclassical quantization, using the ideal magnetohydrodynamic (MHD) ballooning eigenvalue to provide a local dispersion relation, is applied to a ten-field period stellarator test case. Excellent qualitative agreement, and good quantitative agreement is found with predictions from the TERPSICHORE code for toroidal mode numbers from 1 to 14 and radial mode numbers from 0 to 2. The continuum bands predicted from three-dimensional WKB theory are too narrow to resolve. (author) 3 figs., 24 refs

  1. Enzyme allocation problems in kinetic metabolic networks: Optimal solutions are elementary flux modes

    Czech Academy of Sciences Publication Activity Database

    Müller, Stefan; Regensburger, G.; Steuer, Ralf

    2014-01-01

    Roč. 347, APR 2014 (2014), s. 182-190 ISSN 0022-5193 R&D Projects: GA MŠk(CZ) EE2.3.20.0256 Institutional support: RVO:67179843 Keywords : metabolic optimization * enzyme kinetics * oriented matroid * elementary vector * conformal sum Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.116, year: 2014

  2. Adsorption equilibrium and kinetics of Immunoglobulin G on a mixed-mode adsorbent in batch and packed bed configuration.

    Science.gov (United States)

    Gomes, Pedro Ferreira; Loureiro, José Miguel; Rodrigues, Alírio E

    2017-11-17

    It is commonly accepted that efficient protein separation and purification to the desired level of purity is one bottleneck in pharmaceutical industries. MabDirect MM is a new type of mixed mode adsorbent, especially designed to operate in expanded bed adsorption (EBA) mode. In this study, equilibrium and kinetics experiments were carried out for the adsorption of Human Immunoglobulin G (hIgG) protein on this new adsorbent. The effects of ionic strength and pH are assessed. Langmuir isotherms parameters are obtained along with the estimation of the effective pore diffusion coefficient (D pe ) by fitting the batch adsorption kinetics experiments with the pore diffusion model. The maximum adsorption of the IgG protein on the MabDirect MM adsorbent, 149.7±7.1mg·g dry -1 , was observed from a pH 5.0 buffer solution without salt addition. Adding salt to the buffer solution, and/or increasing pH, decreases the adsorption capacity which is 4.7±0.4mg·g dry -1 for pH 7.0 with 0.4M NaCl in solution. Regarding the D pe estimation, a value of 15.4×10 -6 cm 2 ·min -1 was obtained for a pH 5.0 solution without salt. Increasing the salt concentration and/or the pH value will decrease the effective pore diffusion, the lowest D pe (0.16×10 -6 cm 2 ·min -1 ) value being observed for an IgG solution at pH 7.0 with 0.4M NaCl. Fixed bed experiments were conducted with the purpose to validate the equilibrium and kinetic parameters obtained in batch. For a feed concentration of 0.5 g·L -1 of IgG in pH 5.0 buffer solution with 0.4M NaCl, a dynamic binding capacity at 10% of breakthrough of 5.3mg·g wet -1 (15.4mg IgG ·mL resin -1 ) was obtained, representing 62% of the saturation capacity. As far as the authors know, this study is the first one concerning the adsorption of hIgG on this type of mixed mode chromatography adsorbent. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Exponential Growth of Nonlinear Ballooning Instability

    International Nuclear Information System (INIS)

    Zhu, P.; Hegna, C. C.; Sovinec, C. R.

    2009-01-01

    Recent ideal magnetohydrodynamic (MHD) theory predicts that a perturbation evolving from a linear ballooning instability will continue to grow exponentially in the intermediate nonlinear phase at the same linear growth rate. This prediction is confirmed in ideal MHD simulations. When the Lagrangian compression, a measure of the ballooning nonlinearity, becomes of the order of unity, the intermediate nonlinear phase is entered, during which the maximum plasma displacement amplitude as well as the total kinetic energy continues to grow exponentially at the rate of the corresponding linear phase.

  4. Kinetics of Grinding of Secondary Serpentine Raw Material at Cascade Operating Mode

    Directory of Open Access Journals (Sweden)

    Marek Matik

    2004-12-01

    Full Text Available The paper deals with the grinding of secondary serpentine material from the Dobšiná´s heap in a ball ceramic mill. The raw material was pre-sieved to prepare fraction of +250 –1,000 µm that was fed to the mill. During batch experiment an amount of oversize on the screen with a mesh size of 200 µm was observed as a function of time. Two speed modes were tested. Firstly, it was the mode designed by mill producer implicit from the structure of milling stand equipped by electromotor, friction gear onto driving shaft with given diameter. The speed of this original alignment attains 40 rmp. Secondly, it was cascade speed mode according to the Haase´s equation, namely 53 rmp, achieved by enlargement of driving shaft diameter. As to winning of required final product 90 % –200 µm, increased speed resulted in the shortening of grinding time from 17.5 to15.7 hour.

  5. GHOST balloons around Antarctica

    Science.gov (United States)

    Stearns, Charles R.

    1988-01-01

    The GHOST balloon position as a function of time data shows that the atmospheric circulation around the Antarctic Continent at the 100 mb and 200 mb levels is complex. The GHOST balloons supposedly follow the horizontal trajectory of the air at the balloon level. The position of GHOST balloon 98Q for a three month period in 1968 is shown. The balloon moved to within 2 deg of the South Pole on 1 October 1968 and then by 9 December 1968 was 35 deg from the South Pole and close to its position on 1 September 1968. The balloon generally moved from west to east but on two occasions moved in the opposite direction for a few days. The latitude of GHOST balloons 98Q and 149Z which was at 200 mb is given. Both balloons tended to get closer to the South Pole in September and October. Other GHOST balloons at the same pressure and time period may not indicate similar behavior.

  6. Weather Balloon Ascent Rate

    Science.gov (United States)

    Denny, Mark

    2016-05-01

    The physics of a weather balloon is analyzed. The surprising aspect of the motion of these balloons is that they ascend to great altitudes (typically 35 km) at a more or less constant rate. Such behavior is not surprising near the ground—say for a helium-filled party balloon rising from street level to the top of the Empire State building—but it is unexpected for a balloon that rises to altitudes where the air is rarefied. We show from elementary physical laws why the ascent rate is approximately constant.

  7. Kinetic Modifications to MHD Phenomena in Toroidal Plasmas

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Gorelenkov, N.N.; Kramer, G.J.; Fredrickson, E.

    2004-01-01

    Particle kinetic effects involving small spatial and fast temporal scales can strongly affect MHD phenomena and the long time behavior of plasmas. In particular, kinetic effects such as finite ion gyroradii, trapped particle dynamics, and wave-particle resonances have been shown to greatly modify the stability of MHD modes. Here, the kinetic effects of trapped electron dynamics and finite ion gyroradii are shown to have a large stabilizing effect on kinetic ballooning modes in low aspect ratio toroidal plasmas such as NSTX [National Spherical Torus Experiment]. We also present the analysis of Toroidicity-induced Alfven Eigenmodes (TAEs) destabilized by fast neutral-beam injected ions in NSTX experiments and TAE stability in ITER due to alpha-particles and MeV negatively charged neutral beam injected ions

  8. Degradation kinetics of reactive dye by UV/H2O2/US process under continuous mode operation.

    Science.gov (United States)

    Fung, P C; Poon, C S; Chu, C W; Tsui, S M

    2001-01-01

    Degradation of a dye, C. I . Reactive Red 120, in dyeing waatewater by the process o UV/H2O2/US was studied with a bench-scale reactor under the continuous mode of operation. The effects of dyeing wastewater flow rate and the feeding rate of an oxidant, H2O2, on the color removal efficiency of the process were investigated. The significance of ultrasonic (US) combined with UV irradiation was also investigated and the performances of the process on color removal were evaluated. The results showed that the decoloration process followed a pseudo first-order kinetic model and the UV light is the most significant factor on dye removal. Besides, at higher flow rates, incomplete color removal was observed due to relatively insufficient irradiation time (low degradation rate). In order to achieve a higher degradation rate, the feeding rate of H2O2 should be increased.

  9. [Microbial biomass and growth kinetics of microorganisms in chernozem soils under different farm land use modes].

    Science.gov (United States)

    Blagodatskiĭ, S A; Bogomolova, I N; Blagodatskaia, E V

    2008-01-01

    The carbon content of microbial biomass and the kinetic characteristics of microbial respiration response to substrate introduction have been estimated for chernozem soils of different farm lands: arable lands used for 10, 46, and 76 years, mowed fallow land, non-mowed fallow land, and woodland. Microbial biomass and the content of microbial carbon in humus (Cmic/Corg) decreased in the following order: soils under forest cenoses-mowed fallow land-10-year arable land-46- and 75-year arable land. The amount of microbial carbon in the long-plowed horizon was 40% of its content in the upper horizon of non-mowed fallow land. Arable soils were characterized by a lower metabolic diversity of microbial community and by the highest portion of microorganisms able to grow directly on glucose introduced into soil. The effects of different scenarios of carbon sequestration in soil on the reserves and activity of microbial biomass are discussed.

  10. Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

    Science.gov (United States)

    Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

    2016-01-01

    Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Clefting in pumpkin balloons

    Science.gov (United States)

    Baginski, F.; Schur, W.

    NASA's effort to develop a large payload, high altitude, long duration balloon, the Ultra Long Duration Balloon, focuses on a pumpkin shape super-pressure design. It has been observed that a pumpkin balloon may be unable to pressurize into the desired cyclically symmetric equilibrium configuration, settling into a distorted, undesired stable state instead. Hoop stress considerations in the pumpkin design leads to choosing the lowest possible bulge radius, while robust deployment is favored by a large bulge radius. Some qualitative understanding of design aspects on undesired equilibria in pumpkin balloons has been obtained via small-scale balloon testing. Poorly deploying balloons have clefts, but most gores away from the cleft deploy uniformly. In this paper, we present models for pumpkin balloons with clefts. Long term success of the pumpkin balloon for NASA requires a thorough understanding of the phenomenon of multiple stable equilibria and means for quantitative assessment of measures that prevent their occurrence. This paper attempts to determine numerical thresholds of design parameters that distinguish between properly deploying designs and improperly deploying designs by analytically investigating designs in the vicinity of criticality. Design elements which may trigger the onset undesired equilibria and remedial measures that ensure deployment are discussed.

  12. Modelling Hot Air Balloons.

    Science.gov (United States)

    Brimicombe, M. W.

    1991-01-01

    A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

  13. Improving the theoretical foundations of the multi-mode transport model

    International Nuclear Information System (INIS)

    Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

    1999-01-01

    A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

  14. Improving the theoretical foundations of the multi-mode transport model

    International Nuclear Information System (INIS)

    Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

    2001-01-01

    A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

  15. Two Tethered Balloon Systems

    Science.gov (United States)

    Youngbluth, Otto; Owens, Thomas L.; Storey, Richard W.

    1990-01-01

    Systems take meteorological measurements for variety of research projects. Report describes work done by NASA Langley Research Center in atmospheric research using tethered balloon systems composed of commercially available equipment. Two separate tethered balloon systems described in report have payloads and configurations tailored to requirements of specific projects. Each system capable of measuring atmospheric parameter or species in situ and then telemetering this data in real time to ground station. Meteorological data and concentration of ozone typically measured. Indicates instrumented tethered balloon systems have distinct advantages over other systems for gathering data on troposphere.

  16. Drift mode calculations for the Large Helical Device

    International Nuclear Information System (INIS)

    Rewoldt, G.; Ku, L.-P.; Tang, W.M.; Sugama, H.; Nakajima, N.; Watanabe, K.Y.; Murakami, S.; Yamada, H.; Cooper, W.A.

    2000-01-01

    A fully kinetic assessment of the stability properties of toroidal drift modes has been obtained for a case for the Large Helical Device (LHD) [A.Iiyoshi, et al., Plasma Physics and Controlled Nuclear Fusion Research, 1998, Nucl.Fusion 39, 1245 (1999)]. This calculation retains the important effects in the linearized gyrokinetic equation, using the lowest-order ''ballooning representation'' for high toroidal mode number instabilities in the electrostatic limit. Results for toroidal drift waves destabilized by trapped particle dynamics and ion temperature gradients are presented, using three-dimensional magnetohydrodynamics equilibria reconstructed from experimental measurements. The effects of helically-trapped particles and helical curvature are investigated

  17. Ballooning Interest in Science.

    Science.gov (United States)

    Kim, Hy

    1992-01-01

    Presents an activity in which students construct model hot air balloons to introduce the concepts of convection current, the principles of Charles' gas law, and three-dimensional geometric shapes. Provides construction and launching instructions. (MDH)

  18. Ballooning Stability of the Compact Quasiaxially Symmetric Stellarator

    International Nuclear Information System (INIS)

    Redi, M.H.; Canik, J.; Dewar, R.L.; Johnson, J.L.; Klasky, S.; Cooper, W.A.; Kerbichler, W.

    2001-01-01

    The magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), expected to achieve good stability and particle confinement is examined with a method that can lead to estimates of global stability. Making use of fully 3D, ideal-MHD stability codes, the QAS beta is predicted to be limited above 4% by ballooning and high-n kink modes. Here MHD stability is analyzed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in the 3-space [s, alpha, theta(subscript ''k'')]; s is the edge normalized toroidal flux, alpha is the field line variable, and theta(subscript ''k'') is the perpendicular wave vector or ballooning parameter. Broken symmetry, i.e., deviations from axisymmetry, in the stellarator magnetic field geometry causes localization of the ballooning mode eigenfunction, with new types of nonsymmetric, eigenvalue isosurfaces in both the stable and unstable spectrum. The isosurfaces around the most unstable points i n parameter space (well above marginal) are topologically spherical. In such cases, attempts to use ray tracing to construct global ballooning modes lead to a k-space runaway. Introduction of a reflecting cutoff in k(perpendicular) to model numerical truncation or finite Larmor radius (FLR) yields chaotic ray paths ergodically filling the allowed phase space, indicating that the global spectrum must be described using the language of quantum chaos theory. However, the isosurface for marginal stability in the cases studied are found to have a more complex topology, making estimation of FLR stabilization more difficult

  19. Global gyrokinetic simulations of the H-mode tokamak edge pedestal

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Weigang; Parker, Scott E.; Chen, Yang [Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Groebner, Richard J. [General Atomics, Post Office Box 85068, San Diego, California 92186 (United States); Yan, Zheng [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Pankin, Alexei Y.; Kruger, Scott E. [Tech-X Corporation, 5621 Arapahoe Ave., Boulder, Colorado 80305 (United States)

    2013-05-15

    Global gyrokinetic simulations of DIII-D H-mode edge pedestal show two types of instabilities may exist approaching the onset of edge localized modes: an intermediate-n, high frequency mode which we identify as the “kinetic peeling ballooning mode (KPBM),” and a high-n, low frequency mode. Our previous study [W. Wan et al., Phys. Rev. Lett. 109, 185004 (2012)] has shown that when the safety factor profile is flattened around the steep pressure gradient region, the high-n mode is clearly kinetic ballooning mode and becomes the dominant instability. Otherwise, the KPBM dominates. Here, the properties of the two instabilities are studied by varying the density and temperature profiles. It is found that the KPBM is destabilized by density and ion temperature gradient, and the high-n mode is mostly destabilized by electron temperature gradient. Nonlinear simulations with the KPBM saturate at high levels. The equilibrium radial electric field (E{sub r}) reduces the transport. The effect of the parallel equilibrium current is found to be weak.

  20. Launching Garbage-Bag Balloons.

    Science.gov (United States)

    Kim, Hy

    1997-01-01

    Presents a modification of a procedure for making and launching hot air balloons made out of garbage bags. Student instructions for balloon construction, launching instructions, and scale diagrams are included. (DDR)

  1. Stability analysis and trend study of a balloon tethered in a wind, with experimental comparisons

    Science.gov (United States)

    Redd, L. T.; Bland, S. R.; Bennett, R. M.

    1973-01-01

    A stability analysis and trend study for a balloon tethered in a steady wind are presented. The linearized, stability-derivative type analysis includes balloon aerodynamics, buoyancy, mass (including apparent mass), and static forces resulting from the tether cable. The analysis has been applied to a balloon 7.64 m in length, and the results are compared with those from tow tests of this balloon. This comparison shows that the analysis gives reasonable predictions for the damping, frequencies, modes of motion, and stability boundaries exhibited by the balloon. A trend study for the 7.64-m balloon was made to illustrate how the stability boundaries are affected by changes in individual stability parameters. The trends indicated in this study may also be applicable to many other tethered-balloon systems.

  2. JACEE long duration balloon flights

    International Nuclear Information System (INIS)

    Burnett, T.; Iwai, J.; Lord, J.J.; Strausz, S.; Wilkes, R.J.; Dake, S.; Oda, H.; Miyamura, O.; Fuki, M.; Jones, W.V.; Gregory, J.; Hayashi, T.; Takahashi, U.; Tominaga, Y.; Wefel, J.P.; Fountain, W.; Derrickson, J.; Parnell, T.A.; Roberts, E.; Tabuki, T.; Watts, J.W.

    1989-01-01

    JACEE balloon-borne emulsion chamber detectors are used to observe the spectra and interactions of cosmic ray protons and nuclei in the energy range 1-100A TeV. Experience with long duration mid-latitude balloon flights and characteristics of the detector system that make it ideal for planned Antarctic balloon flights are discussed. 5 refs., 2 figs

  3. Edge-localized mode avoidance and pedestal structure in I-mode plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Walk, J. R., E-mail: jrwalk@psfc.mit.edu; Hughes, J. W.; Hubbard, A. E.; Terry, J. L.; Whyte, D. G.; White, A. E.; Baek, S. G.; Reinke, M. L.; Theiler, C.; Churchill, R. M.; Rice, J. E. [MIT Plasma Science and Fusion Center, Cambridge, MA 02139-4307 (United States); Snyder, P. B.; Osborne, T. [General Atomics, San Diego, CA 92186-5608 (United States); Dominguez, A [Princeton Plasma Physics Laboratory, Princeton, NJ 08543-0451 (United States); Cziegler, I. [UCSD Center for Momentum Transport and Flow Organization, La Jolla, CA 92093-0417 (United States)

    2014-05-15

    I-mode is a high-performance tokamak regime characterized by the formation of a temperature pedestal and enhanced energy confinement, without an accompanying density pedestal or drop in particle and impurity transport. I-mode operation appears to have naturally occurring suppression of large Edge-Localized Modes (ELMs) in addition to its highly favorable scalings of pedestal structure and overall performance. Extensive study of the ELMy H-mode has led to the development of the EPED model, which utilizes calculations of coupled peeling-ballooning MHD modes and kinetic-ballooning mode (KBM) stability limits to predict the pedestal structure preceding an ELM crash. We apply similar tools to the structure and ELM stability of I-mode pedestals. Analysis of I-mode discharges prepared with high-resolution pedestal data from the most recent C-Mod campaign reveals favorable pedestal scalings for extrapolation to large machines—pedestal temperature scales strongly with power per particle P{sub net}/n{sup ¯}{sub e}, and likewise pedestal pressure scales as the net heating power (consistent with weak degradation of confinement with heating power). Matched discharges in current, field, and shaping demonstrate the decoupling of energy and particle transport in I-mode, increasing fueling to span nearly a factor of two in density while maintaining matched temperature pedestals with consistent levels of P{sub net}/n{sup ¯}{sub e}. This is consistent with targets for increased performance in I-mode, elevating pedestal β{sub p} and global performance with matched increases in density and heating power. MHD calculations using the ELITE code indicate that I-mode pedestals are strongly stable to edge peeling-ballooning instabilities. Likewise, numerical modeling of the KBM turbulence onset, as well as scalings of the pedestal width with poloidal beta, indicates that I-mode pedestals are not limited by KBM turbulence—both features identified with the trigger for large ELMs

  4. The EPED pedestal model and edge localized mode-suppressed regimes: Studies of quiescent H-mode and development of a model for edge localized mode suppression via resonant magnetic perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, P. B.; Osborne, T. H.; Burrell, K. H.; Groebner, R. J.; Leonard, A. W.; Wade, M. R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Nazikian, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey (United States); Orlov, D. M. [University of California-San Diego, San Diego, California 92093 (United States); Schmitz, O. [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, Association FZJ-EURATOM, Juelich (Germany); Wilson, H. R. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2012-05-15

    The EPED model predicts the H-mode pedestal height and width based upon two fundamental and calculable constraints: (1) onset of non-local peeling-ballooning modes at low to intermediate mode number, (2) onset of nearly local kinetic ballooning modes at high mode number. We present detailed tests of the EPED model in discharges with edge localized modes (ELMs), employing new high resolution measurements, and finding good quantitative agreement across a range of parameters. The EPED model is then applied for the first time to quiescent H-mode (QH), finding a similar level of agreement between predicted and observed pedestal height and width, and suggesting that the model can be used to predict the critical density for QH-mode operation. Finally, the model is applied toward understanding the suppression of ELMs with 3D resonant magnetic perturbations (RMP). Combining EPED with plasma response physics, a new working model for RMP ELM suppression is developed. We propose that ELMs are suppressed when a 'wall' associated with the RMP blocks the inward penetration of the edge transport barrier. A calculation of the required location of this 'wall' with EPED is consistent with observed profile changes during RMP ELM suppression and offers an explanation for the observed dependence on safety factor (q{sub 95}).

  5. Adjustable continence balloons

    DEFF Research Database (Denmark)

    Kjær, Line; Fode, Mikkel; Nørgaard, Nis

    2012-01-01

    Abstract Objective. This study aimed to evaluate the results of the Danish experience with the ProACT urinary continence device inserted in men with stress urinary incontinence. Material and methods. The ProACT was inserted in 114 patients. Data were registered prospectively. The main endpoints...... in urinary leakage > 50% was seen in 72 patients (80%). Complications were seen in 23 patients. All of these were treated successfully by removal of the device in the outpatient setting followed by replacement of the device. Another eight patients had a third balloon inserted to improve continence further....... Fourteen patients (12%) ended up with an artificial sphincter or a urethral sling. Sixty patients (63%) experienced no discomfort and 58 (61%) reported being dry or markedly improved. Overall, 50 patients (53%) reported being very or predominantly satisfied. Conclusions. Adjustable continence balloons seem...

  6. Hot air balloon engine

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, Ian [Solartran Pty Ltd, 12 Lentara Street, Kenmore, Brisbane 4069 (Australia)

    2009-04-15

    This paper describes a solar powered reciprocating engine based on the use of a tethered hot air balloon fuelled by hot air from a glazed collector. The basic theory of the balloon engine is derived and used to predict the performance of engines in the 10 kW to 1 MW range. The engine can operate over several thousand metres altitude with thermal efficiencies higher than 5%. The engine thermal efficiency compares favorably with the efficiency of other engines, such as solar updraft towers, that also utilize the atmospheric temperature gradient but are limited by technical constraints to operate over a much lower altitude range. The increased efficiency allows the use of smaller area glazed collectors. Preliminary cost estimates suggest a lower $/W installation cost than equivalent power output tower engines. (author)

  7. Spectrum of the ballooning Schroedinger equation

    International Nuclear Information System (INIS)

    Dewar, R.L.

    1997-01-01

    The ballooning Schroedinger equation (BSE) is a model equation for investigating global modes that can, when approximated by a Wentzel-Kramers-Brillouin (WKB) ansatz, be described by a ballooning formalism locally to a field line. This second order differential equation with coefficients periodic in the independent variable θ k is assumed to apply even in cases where simple WKB quantization conditions break down, thus providing an alternative to semiclassical quantization. Also, it provides a test bed for developing more advanced WKB methods: e.g. the apparent discontinuity between quantization formulae for open-quotes trappedclose quotes and open-quotes passingclose quotes modes, whose ray paths have different topologies, is removed by extending the WKB method to include the phenomena of tunnelling and reflection. The BSE is applied to instabilities with shear in the real part of the local frequency, so that the dispersion relation is inherently complex. As the frequency shear is increased, it is found that trapped modes go over to passing modes, reducing the maximum growth rate by averaging over θ k

  8. Cleft formation in pumpkin balloons

    Science.gov (United States)

    Baginski, Frank E.; Brakke, Kenneth A.; Schur, Willi W.

    NASA’s development of a large payload, high altitude, long duration balloon, the Ultra Long Duration Balloon, centers on a pumpkin shape super-pressure design. Under certain circumstances, it has been observed that a pumpkin balloon may be unable to pressurize into the desired cyclically symmetric equilibrium configuration, settling into a distorted, undesired state instead. Success of the pumpkin balloon for NASA requires a thorough understanding of the phenomenon of multiple stable equilibria and developing of means for the quantitative assessment of design measures that prevent the occurrence of undesired equilibrium. In this paper, we will use the concept of stability to classify cyclically symmetric equilibrium states at full inflation and pressurization. Our mathematical model for a strained equilibrium balloon, when applied to a shape that mimics the Phase IV-A balloon of Flight 517, predicts instability at float. Launched in Spring 2003, this pumpkin balloon failed to deploy properly. Observations on pumpkin shape type super-pressure balloons that date back to the 1980s suggest that within a narrowly defined design class of pumpkin shape super-pressure balloons where individual designs are fully described by the number of gores ng and by a single measure of the bulging gore shape, the designs tend to become more vulnerable with the growing number of gores and with the diminishing size of the bulge radius rB Weight efficiency considerations favor a small bulge radius, while robust deployment into the desired cyclically symmetrical configuration becomes more likely with an increased bulge radius. In an effort to quantify this dependency, we will explore the stability of a family of balloon shapes parametrized by (ng, rB) which includes a design that is very similar, but not identical, to the balloon of Flight 517. In addition, we carry out a number of simulations that demonstrate other aspects related to multiple equilibria of pumpkin balloons.

  9. Physics basis of Multi-Mode anomalous transport module

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, T.; Kritz, A. H.; Luo, L. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Weiland, J. [Departments of Applied Physics, Chalmers University of Technology and Euratom-VR Assoc., S41296 Gothenburg (Sweden); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado (United States)

    2013-03-15

    The derivation of Multi-Mode anomalous transport module version 8.1 (MMM8.1) is presented. The MMM8.1 module is advanced, relative to MMM7.1, by the inclusion of peeling modes, dependence of turbulence correlation length on flow shear, electromagnetic effects in the toroidal momentum diffusivity, and the option to compute poloidal momentum diffusivity. The MMM8.1 model includes a model for ion temperature gradient, trapped electron, kinetic ballooning, peeling, collisionless and collision dominated magnetohydrodynamics modes as well as model for electron temperature gradient modes, and a model for drift resistive inertial ballooning modes. In the derivation of the MMM8.1 module, effects of collisions, fast ion and impurity dilution, non-circular flux surfaces, finite beta, and Shafranov shift are included. The MMM8.1 is used to compute thermal, particle, toroidal, and poloidal angular momentum transports. The fluid approach which underlies the derivation of MMM8.1 is expected to reliably predict, on an energy transport time scale, the evolution of temperature, density, and momentum profiles in plasma discharges for a wide range of plasma conditions.

  10. Upper gastrointestinal strictures: The results of balloon dilatation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kil Woo; Lim, Hyo Keun; Choo, In Wook; Bae, Sang Hoon; Yoon, Jong Sup [Hallym University College of Medicine, Seoul (Korea, Republic of); Yoo, Hyung Sik [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1990-12-15

    Balloon catheter dilatation of upper gastrointestinal strictures is an accepted mode of therapy. The authors report the balloon dilatation in 11 consecutive patients. The lesions treated included 10 benign strictures, and 1 esophageal cancer. Esophageal balloon were ranged from 2 mm in diameter, 4 cm in length, to 30 mm in diameter, 8 cm in length. Inflation was held for from 30 to 60 seconds and then repeated two or three times during each session. The balloons were inflated to pressure of from 2 to 12 atmospheres. There were from 1 to 13 dilatations. Two esophageal perforations were occurred in one esophagitis patient and other lye stricture patient. Two perforations were not required any surgical repair. All dilatation were performed without anesthesia. All strictures were responded immediately to dilatation. Prolonged course of treatment were needed with chronic severe esophagitis, lye stricture, gastrojejunostomy with chemotherapy, as a result, all patients, except esophageal cancer, could take regular diet after balloon catheter dilatation. Balloon catheter dilatation of upper gastrointestinal stenosis was effective and safe. It should be considered before other methods of treatment applicable.

  11. Pedestal structure and stability in H-mode and I-mode: a comparative study on Alcator C-Mod

    International Nuclear Information System (INIS)

    Hughes, J.W.; Walk, J.R.; Davis, E.M.; LaBombard, B.; Baek, S.G.; Churchill, R.M.; Greenwald, M.; Hubbard, A.E.; Lipschultz, B.; Marmar, E.S.; Reinke, M.L.; Rice, J.E.; Theiler, C.; Terry, J.; White, A.E.; Whyte, D.G.; Snyder, P.B.; Groebner, R.J.; Osborne, T.; Diallo, A.

    2013-01-01

    New experimental data from the Alcator C-Mod tokamak are used to benchmark predictive modelling of the edge pedestal in various high-confinement regimes, contributing to greater confidence in projection of pedestal height and width in ITER and reactors. ELMy H-modes operate near stability limits for ideal peeling–ballooning modes, as shown by calculations with the ELITE code. Experimental pedestal width in ELMy H-mode scales as the square root of β pol at the pedestal top, i.e. the dependence expected from theory if kinetic ballooning modes (KBMs) were responsible for limiting the pedestal width. A search for KBMs in experiment has revealed a short-wavelength electromagnetic fluctuation in the pedestal that is a candidate driver for inter-edge localized mode (ELM) pedestal regulation. A predictive pedestal model (EPED) has been tested on an extended set of ELMy H-modes from C-Mod, reproducing pedestal height and width reasonably well across the data set, and extending the tested range of EPED to the highest absolute pressures available on any existing tokamak and to within a factor of three of the pedestal pressure targeted for ITER. In addition, C-Mod offers access to two regimes, enhanced D-alpha (EDA) H-mode and I-mode, that have high pedestals, but in which large ELM activity is naturally suppressed and, instead, particle and impurity transport are regulated continuously. Pedestals of EDA H-mode and I-mode discharges are found to be ideal magnetohydrodynamic (MHD) stable with ELITE, consistent with the general absence of ELM activity. Invocation of alternative physics mechanisms may be required to make EPED-like predictions of pedestals in these kinds of intrinsically ELM-suppressed regimes, which would be very beneficial to operation in burning plasma devices. (paper)

  12. Balloon launching station, Mildura, Victoria

    International Nuclear Information System (INIS)

    The Mildura Balloon Launching Station was established in 1960 by the Department of Supply (now the Department of Manufacturing Industry) on behalf of the United States Atomic Energy Commission (USAEC) to determine the content of radioactive material in the upper atmosphere over Australia. The Station location and layout, staffing, balloon launching equipment, launching, tracking and recovery are described. (R.L.)

  13. Simultaneous spectral and temporal analyses of kinetic energies in nonequilibrium systems: theory and application to vibrational relaxation of O-D stretch mode of HOD in water.

    Science.gov (United States)

    Jeon, Jonggu; Lim, Joon Hyung; Kim, Seongheun; Kim, Heejae; Cho, Minhaeng

    2015-05-28

    A time series of kinetic energies (KE) from classical molecular dynamics (MD) simulation contains fundamental information on system dynamics. It can also be analyzed in the frequency domain through Fourier transformation (FT) of velocity correlation functions, providing energy content of different spectral regions. By limiting the FT time span, we have previously shown that spectral resolution of KE evolution is possible in the nonequilibrium situations [Jeon and Cho, J. Chem. Phys. 2011, 135, 214504]. In this paper, we refine the method by employing the concept of instantaneous power spectra, extending it to reflect an instantaneous time-correlation of velocities with those in the future as well as with those in the past, and present a new method to obtain the instantaneous spectral density of KE (iKESD). This approach enables the simultaneous spectral and temporal resolution of KE with unlimited time precision. We discuss the formal and novel properties of the new iKESD approaches and how to optimize computational methods and determine parameters for practical applications. The method is specifically applied to the nonequilibrium MD simulation of vibrational relaxation of the OD stretch mode in a hydrated HOD molecule by employing a hybrid quantum mechanical/molecular mechanical (QM/MM) potential. We directly compare the computational results with the OD band population relaxation time profiles extracted from the IR pump-probe measurements for 5% HOD in water. The calculated iKESD yields the OD bond relaxation time scale ∼30% larger than the experimental value, and this decay is largely frequency-independent if the classical anharmonicity is accounted for. From the integrated iKESD over intra- and intermolecular bands, the major energy transfer pathways were found to involve the HOD bending mode in the subps range, then the internal modes of the solvent until 5 ps after excitation, and eventually the solvent intermolecular modes. Also, strong hydrogen

  14. Feasibility of creating a specialized reactimeter based on the inverse solution to kinetics equation with a current-mode neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Koshelev, A. S., E-mail: alexsander.coshelev@yandex.ru; Arapov, A. V.; Ovchinnikov, M. A. [Russian Federal Nuclear Center–All-Russian Research Institute of Experimental Physics (Russian Federation)

    2016-12-15

    The file-evaluation results of a reactimeter based on the inverse solution to the kinetics equation (ISKE) are presented, which were obtained using an operating hardware-measuring complex with a KNK-4 neutron detector working in the current mode. The processing of power-recording files of the BR-1M, BR-K1, and VIR-2M reactors of the Russian Federal Nuclear Center—All-Russian Research Institute of Experimental Physics, which was performed with the use of Excel simulation of the ISKE formalism, demonstrated the feasibility of implementation of the reactivity monitoring (during the operation of these reactors at stationary power) beginning from the level of ~5 × 10{sup –4}β{sub eff}.

  15. Kinetic stability analyses in a bumpy cylinder

    International Nuclear Information System (INIS)

    Dominguez, R.R.; Berk, H.L.

    1981-01-01

    Recent interest in the ELMO Bumpy Torus (EBT) has prompted a number of stability analyses of both the hot electron rings and the toroidal plasma. Typically these works employ the local approximation, neglecting radial eigenmode structure and ballooning effects to perform the stability analysis. In the present work we develop a fully kinetic formalism for performing nonlocal stability analyses in a bumpy cylinder. We show that the Vlasov-Maxwell integral equations (with one ignorable coordinate) are self-adjoint and hence amenable to analysis using numerical techniques developed for self-adjoint systems of equations. The representation we obtain for the kernel of the Vlasov-Maxwell equations is a differential operator of arbitrarily high order. This form leads to a manifestly self-adjoint system of differential equations for long wavelength modes

  16. 21 CFR 874.4100 - Epistaxis balloon.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Epistaxis balloon. 874.4100 Section 874.4100 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Surgical Devices § 874.4100 Epistaxis balloon. (a) Identification. An epistaxis balloon is a device consisting of an inflatable balloon intended to control internal...

  17. Calculating Payload for a Tethered Balloon System

    Science.gov (United States)

    Charles D. Tangren

    1980-01-01

    A graph method to calculate payload for a tethered balloon system, with the supporting helium lift and payload equations. is described. The balloon system is designed to collect emissions data during the convective-lift and no-convective-lift phases of a forest fire. A description of the balloon system and a list of factors affecting balloon selection are included....

  18. Turbulence fluxes and variances measured with a sonic anemometer mounted on a tethered balloon

    OpenAIRE

    Canut, Guylaine; Couvreux, Fleur; Lothon, Marie; Legain, Dominique; Piguet, Bruno; Lampert, Astrid; Maurel, William; Moulin, Eric

    2016-01-01

    This study presents the first deployment in field campaigns of a balloon-borne turbulence probe, developed with a sonic anemometer and an inertial motion sensor suspended below a tethered balloon. This system measures temperature and horizontal and vertical wind at high frequency and allows the estimation of heat and momentum fluxes as well as turbulent kinetic energy in the lower part of the boundary layer. The system was validated during three field experiments with differ...

  19. N-dependence of ballooning instabilities

    International Nuclear Information System (INIS)

    Dewar, R.L.; Manickam, J.; Grimm, R.C.; Chance, M.S.

    1980-05-01

    The critical β for stability against ideal hydromagnetic internal ballooning modes as a function of toroidal mode number, n, is calculated for two different equilibrium sequences by use of a finite element technique (n less than or equal to 20), and a WKB formalism (n greater than or equal to 5). The agreement between the two methods is good in the overlap region 5 approx.less than or equal to n approx. less than or equal to 20. The WKB formula reduces to the 1/n correction at very high n, but is much more accurate at moderate n. The critical β vs n curves exhibit oscillatory structure at low n, but in both sequences the lower bound on β/sub c/ approx. 5%. For reactor parameters, finite Larmor radius effects are not expected to have a large effect on this β-limitation

  20. Optimal Design of a Traveling-Wave Kinetic Inductance Amplifier Operated in Three-Wave Mixing Mode

    Science.gov (United States)

    Erickson, Robert; Bal, Mustafa; Ku, Ksiang-Sheng; Wu, Xian; Pappas, David

    In the presence of a DC bias, an injected pump, of frequency fP, and a signal, of frequency fS, undergo parametric three-way mixing (3WM) within a traveling-wave kinetic inductance (KIT) amplifier, producing an idler product of frequency fI =fP -fS . Periodic frequency stops are engineered into the coplanar waveguide of the device to enhance signal amplification. With fP placed just above the first frequency stop gap, 3WM broadband signal gain is achieved with maximum gain at fS =fP / 2 . Within a theory of the dispersion of traveling waves in the presence of these engineered loadings, which accounts for this broadband signal gain, we show how an optimal frequency-stop design may be constructed to achieve maximum signal amplification. The optimization approach we describe can be applied to the design of other nonlinear traveling-wave parametric amplifiers. This work was supported by the Army Research Office and the Laboratory for Physical Sciences under EAO221146, EAO241777, and the NIST Quantum Initiative. RPE acknowledges Grant 60NANB14D024 from the US Department of Commerce, NIST.

  1. US Daily Pilot Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pilot Balloon observational forms for the United States. Taken by Weather Bureau and U.S. Army observers. Period of record 1918-1960. Records scanned from the NCDC...

  2. US Air Force Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Worksheets containing pilot balloon data computed from releases at Air Force stations in the western United States. Elevation and azimuth angles are used to compute...

  3. Anderson localization and ballooning eigenfunctions

    International Nuclear Information System (INIS)

    Dewar, R.L.; Cuthbert, P.

    1999-01-01

    In solving the ballooning eigenvalue for a low-aspect-ratio stellarator equilibrium it is found that the quasiperiodic behaviour of the equilibrium quantities along a typical magnetic field line can lead to localization of the ballooning eigenfunction (Anderson localization) even in the limit of zero shear. This localization leads to strong field-line dependence of the ballooning eigenvalue, with different branches attaining their maximum growth rates on different field lines. A method is presented of estimating the field-line dependence of various eigenvalue branches by using toroidal and poloidal symmetry operations on the shear-free ballooning equation to generate an approximate set of eigenfunctions. These zero-shear predictions are compared with accurate numerical solutions for the H-1 Heliac and are shown to give a qualitatively correct picture, but finite shear corrections will be needed to give quantitative predictions

  4. Solar research with stratospheric balloons

    Science.gov (United States)

    Vázquez, Manuel; Wittmann, Axel D.

    Balloons, driven by hot air or some gas lighter than air, were the first artificial machines able to lift payloads (including humans) from the ground. After some pioneering flights the study of the physical properties of the terrestrial atmosphere constituted the first scientific target. A bit later astronomers realized that the turbulence of the atmospheric layers above their ground-based telescopes deteriorated the image quality, and that balloons were an appropriate means to overcome, total or partially, this problem. Some of the most highly-resolved photographs and spectrograms of the sun during the 20th century were actually obtained by balloon-borne telescopes from the stratosphere. Some more recent projects of solar balloon astronomy will also be described.

  5. Retrieving Balloon Data in Flight

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's Ultra Long Duration Balloon (ULDB) program will soon make flights lasting up to 100 days. Some flights may generate high data rates and retrieving this data...

  6. Euso-Balloon: A pathfinder mission for the JEM-EUSO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Osteria, Giuseppe, E-mail: osteria@na.infn.it [Istituto Nazionale di Fisica Nucleare Sezione di Napoli, Naples (Italy); Scotti, Valentina [Istituto Nazionale di Fisica Nucleare Sezione di Napoli, Naples (Italy); Università di Napoli Federico II, Dipartimento di Fisica, Naples (Italy)

    2013-12-21

    EUSO-Balloon is a pathfinder mission for JEM-EUSO, the near-UV telescope proposed to be installed on board the ISS in 2017. The main objective of this pathfinder mission is to perform a full scale end-to-end test of all the key technologies and instrumentation of JEM-EUSO detectors and to prove the entire detection chain. EUSO-Balloon will measure the atmospheric and terrestrial UV background components, in different observational modes, fundamental for the development of the simulations. Through a series of flights performed by the French Space Agency CNES, EUSO-Balloon also has the potential to detect Extensive Air Showers (EAS) from above. EUSO-Balloon will be mounted in an unpressurized gondola of a stratospheric balloon. We will describe the instrument and the electronic system which performs instrument control and data management in such a critical environment.

  7. Pioneering Space Research with Balloons

    Science.gov (United States)

    Jones, W. V.

    NASA s Scientific Ballooning Planning Team has concluded that ballooning enables significant scientific discoveries while providing test beds for space instruments and training for young scientists Circumpolar flights around Antarctica have been spectacularly successful with fight durations up to 42 days Demand for participation in this Long-Duration Balloon LDB program a partnership with the U S National Science Foundation Office of Polar Programs is greater than the current capacity of two flights per campaign Given appropriate international agreements LDB flights in the Northern Hemisphere would be competitive with Antarctic flights and super-pressure balloons would allow comparable flights at any latitude The Balloon Planning Team made several recommendations for LDB flights provide a reliable funding source for sophisticated payloads extend the Antarctic capability to three flights per year and develop a comparable capability in the Arctic provide aircraft for intact-payload recovery develop a modest trajectory modification capability to enable longer flights and enhance super-pressure balloons to carry 1-ton payloads to 38 km Implementation of these recommendations would facilitate frequent access to near-space for cutting-edge research and technology development for a wide range of investigations

  8. Observation of ion scale fluctuations in the pedestal region during the edge-localized-mode cycle on the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, A.; Kramer, G. J.; Bell, R. E.; Guttenfelder, W.; LeBlanc, B. P.; Podesta, M. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Smith, D. R.; McKee, G. J. [Departments of Engineering Physics and Physics, University of Wisconsin, Madison, Wisconsin (United States); Maingi, R. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831 (United States); Fonck, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Departments of Engineering Physics and Physics, University of Wisconsin, Madison, Wisconsin (United States)

    2013-01-15

    Characterization of the spatial structure of turbulence fluctuations during the edge localized mode cycle in the pedestal region is reported. Using the beam emission spectroscopy and the correlation reflectometry systems, measurements show spatial structure-k{sub Up-Tack }{rho}{sub i}{sup ped}-ranging from 0.2 to 0.7 propagating in the ion diamagnetic drift direction at the pedestal top. These propagating spatial scales are found to be anisotropic and consistent with ion-scale microturbulence of the type ion temperature gradient and/or kinetic ballooning modes.

  9. Ballooning instabilities in tokamaks with sheared toroidal flows

    International Nuclear Information System (INIS)

    Waelbroeck, F.L.; Chen, L.

    1990-11-01

    The stability of ballooning modes in the presence of sheared toroidal flows is investigated. The eigenmodes are shown to be related by a Fourier transformation to the non-exponentially growing Floquet solutions found by Cooper. It is further shown that the problem cannot be reduced further than to a two dimensional partial differential equation. Next, the generalized ballooning equation is solved analytically for a circular tokamak equilibrium with sonic flows, but with a small rotation shear compared to the sound speed. With this ordering, the centrifugal forces are comparable to the pressure gradient forces driving the instability, but coupling of the mode with the sound wave is avoided. A new stability criterion is derived which explicitly demonstrates that flow shear is stabilizing at constant centrifugal force gradient. 34 refs

  10. Balloon dilatation of ureteric strictures.

    Directory of Open Access Journals (Sweden)

    Punekar S

    2000-01-01

    Full Text Available AIMS: Evaluation of dilatation as a minimally invasive technique for the treatment of ureteric strictures. MATERIAL AND METHODS: We evaluated this technique in 16 patients with ureteric and secondary pelviureteric junction strictures from June 1998. Of these, 7 were men and 9 were women. The age range was from 14 to 40 years. RESULTS: Balloon dilatation was successful in 69% of patients. Strictures secondary to previous surgery had nearly 100% success. Of the 8 cases diagnosed as genitourinary tuberculosis, success rate was 50%. CONCLUSIONS: Factors affecting success of balloon dilatation are: a age of the stricture b length of the stricture and c etiology of the stricture. In a select group of patients with fresh post-operative or post-inflammatory strictures, balloon dilatation may be an attractive alternative to surgery.

  11. Structure variations of pumpkin balloon

    Science.gov (United States)

    Yajima, N.; Izutsu, N.; Honda, H.

    2004-01-01

    A lobed pumpkin balloon by 3-D gore design concept is recognized as a basic form for a super-pressure balloon. This paper deals with extensions of this design concept for other large pressurized membrane structures, such as a stratospheric airship and a balloon of which volume is controllable. The structural modifications are performed by means of additional ropes, belts or a strut. When the original pumpkin shape is modified by these systems, the superior characteristics of the 3-D gore design, incorporating large bulges with a small local radius and unidirectional film tension, should be maintained. Improved design methods which are adequate for the above subjects will be discussed in detail. Application for ground structures are also mentioned.

  12. Resonant MHD modes with toroidal coupling

    International Nuclear Information System (INIS)

    Connor, J.W.; Hastie, R.J.; Taylor, J.B.

    1990-07-01

    This is part 2 of a study of resonant perturbations, such as resistive tearing and ballooning modes, in a torus. These are described by marginal ideal mhd equations in the regions between resonant surfaces; matching across these surfaces provides the dispersion relation. In part 1 we described how all the necessary information from the ideal mhd calculations could be represented by a so-called E-matrix. We also described the calculation of this E-matrix for tearing modes (even parity in perturbed magnetic field) in a large aspect ratio torus. There the toroidal modes comprise coupled cylinder tearing modes and the E-matrix is a generalization of the familiar Δ' quantity in a cylinder. In the present paper we discuss resistive ballooning, or twisting-modes, which have odd-parity in perturbed magnetic field. We show that, unlike the tearing modes, these odd-parity modes are instrinsically toroidal and are not directly related to the odd-parity modes in a cylinder. This is evident from the analysis of the high-n limit in ballooning-space, where a transition from a stable Δ' to an unstable Δ' occurs for the twisting mode when the ballooning effect exceeds the interchange effect, which can occur even at large aspect ratio (as in a tokamak). Analysis of the high-n limit in coordinate space, rather than ballooning space, clarifies this singular behaviour and indicates how one may define twisting-mode Δ'. It also yields a prescription for treating low-n twisting modes and a method for calculating an E-matrix for resistive ballooning modes in a large aspect ratio tokamak. The elements of this matrix are given in terms of cylindrical tearing mode solutions

  13. Mars Solar Balloon Lander, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Solar Balloon Lander (MSBL) is a novel concept which utilizes the capability of solar-heated hot air balloons to perform soft landings of scientific...

  14. Taking the Hot Air Out of Balloons.

    Science.gov (United States)

    Brinks, Virgil L.; Brinks, Robyn L.

    1994-01-01

    Describes how a teacher can give their students the challenge of designing and building model balloons or blimps. The project helps students learn the basics of balloon flight and what it really means to be "lighter than air." (PR)

  15. Ballooning instabilities in toroidally linked mirror systems

    International Nuclear Information System (INIS)

    Hastie, R.J.; Watson, C.J.H.

    1977-01-01

    This paper examines the stability against ballooning modes of plasma equilibria in toroidally linked mirror configurations consisting of a number of quadrupole minimum-B mirrors linked toroidally. On the basis of the Kruskal-Oberman energy principle, a class of displacements is identified which are potentially unstable, and a necessary criterion for stability is derived. The criterion is obtained from the eigenvalues of an ordinary differential equation, which determines the variation of the displacement along a field line. The coefficients in the equation are determined by the configuration, and by inserting various model configurations, estimates are obtained of the maximum value of β consistent with stability. In cases of interest, quite high β-values are obtained. (author)

  16. Complications of balloon packing in epistaxis

    NARCIS (Netherlands)

    Vermeeren, Lenka; Derks, Wynia; Fokkens, Wytske; Menger, Dirk Jan

    2015-01-01

    Although balloon packing appears to be efficient to control epistaxis, severe local complications can occur. We describe four patients with local lesions after balloon packing. Prolonged balloon packing can cause damage to nasal mucosa, septum and alar skin (nasal mucosa, the cartilaginous skeleton

  17. Scientific Ballooning in India - Recent Developments

    Science.gov (United States)

    Manchanda, R. K.; Srinivasan, S.; Subbarao, J. V.

    Established in 1972, the National Balloon Facility operated by TIFR in Hyderabad, India is is a unique facility in the country, which provides a complete solution in scientific ballooning. It is also one of its kind in the world since it combines both, the in-house balloon production and a complete flight support for scientific ballooning. With a large team working through out the year to design, fabricate and launch scientific balloons, the Hyderabad Facility is a unique centre of expertise where the balloon design, Research and Development, the production and launch facilities are located under one roof. Our balloons are manufactured from 100% indigenous components. The mission specific balloon design, high reliability control and support instrumentation, in-house competence in tracking, telemetry, telecommand, data processing, system design and mechanics is a hallmark of the Hyderabad balloon facility. In the past few years we have executed a major programme of upgradation of different components of balloon production, telemetry and telecommand hardware and various support facilities. This paper focuses on our increased capability of balloon production of large sizes up to size of 780,000 M^3 using Antrix film, development of high strength balloon load tapes with the breaking strength of 182 kg, and the recent introduction of S-band telemetry and a commandable timer cut-off unit in the flight hardware. A summary of the various flights conducted in recent years will be presented along with the plans for new facilities.

  18. PROGRESS IN THE PEELING-BALLOONING MODEL OF ELMS: NUMERICAL STUDIES OF 3D NONLINEAR ELM DYNAMICS

    International Nuclear Information System (INIS)

    SNYDER, P.B.; WILSON, H.R.; XU, X.Q.

    2004-01-01

    Nonlinear simulations with the 3D electromagnetic two-fluid BOUT code are employed to study the dynamics of edge localized modes (ELMs) driven by intermediate wavelength peeling-ballooning modes. It is found that the early behavior of the modes is similar to expectations from linear, ideal peeling-ballooning mode theory, with the modes growing linearly at a fraction of the Alfven frequency. In the nonlinear phase, the modes grow explosively, forming a number of extended filaments which propagate rapidly from the outer closed flux region into the open flux region toward the outboard wall. Similarities to non-linear ballooning theory, as well as additional complexities are observed. Comparison to observations reveals a number of similarities. Implications of the simulations and proposals for the dynamics of the full ELM crash are discussed

  19. Simulating clefts in pumpkin balloons

    Science.gov (United States)

    Baginski, Frank; Brakke, Kenneth

    2010-02-01

    The geometry of a large axisymmetric balloon with positive differential pressure, such as a sphere, leads to very high film stresses. These stresses can be significantly reduced by using a tendon re-enforced lobed pumpkin-like shape. A number of schemes have been proposed to achieve a cyclically symmetric pumpkin shape, including the constant bulge angle (CBA) design, the constant bulge radius (CBR) design, CBA/CBR hybrids, and NASA’s recent constant stress (CS) design. Utilizing a hybrid CBA/CBR pumpkin design, Flight 555-NT in June 2006 formed an S-cleft and was unable to fully deploy. In order to better understand the S-cleft phenomenon, a series of inflation tests involving four 27-m diameter 200-gore pumpkin balloons were conducted in 2007. One of the test vehicles was a 1/3-scale mockup of the Flight 555-NT balloon. Using an inflation procedure intended to mimic ascent, the 1/3-scale mockup developed an S-cleft feature strikingly similar to the one observed in Flight 555-NT. Our analysis of the 1/3-scale mockup found it to be unstable. We compute asymmetric equilibrium configurations of this balloon, including shapes with an S-cleft feature.

  20. Laser welding of balloon catheters

    Science.gov (United States)

    Flanagan, Aidan J.

    2003-03-01

    The balloon catheter is one of the principal instruments of non-invasive vascular surgery. It is used most commonly for angioplasty (and in recent years for delivering stents) at a multitude of different sites in the body from small arteries in the heart to the bilary duct. It is composed of a polymer balloon that is attached to a polymer shaft at two points called the distal and proximal bonds. The diverse utility of balloon catheters means a large range of component sizes and materials are used during production; this leads to a complexity of bonding methods and technology. The proximal and distal bonds have been conventionally made using cyanoacrylate or UV curing glue, however with performance requirements of bond strength, flexibility, profile, and manufacturing costs these bonds are increasingly being made by welding using laser, RF, and Hot Jaw methods. This paper describes laser welding of distal and proximal balloon bonds and details beam delivery, bonding mechanisms, bond shaping, laser types, and wavelength choice.

  1. High-frequency coherent edge fluctuations in a high-pedestal-pressure quiescent H-mode plasma.

    Science.gov (United States)

    Yan, Z; McKee, G R; Groebner, R J; Snyder, P B; Osborne, T H; Burrell, K H

    2011-07-29

    A set of high frequency coherent (HFC) modes (f=80-250 kHz) is observed with beam emission spectroscopy measurements of density fluctuations in the pedestal of a strongly shaped quiescent H-mode plasma on DIII-D, with characteristics predicted for kinetic ballooning modes (KBM): propagation in the ion-diamagnetic drift direction; a frequency near 0.2-0.3 times the ion-diamagnetic frequency; inferred toroidal mode numbers of n∼10-25; poloidal wave numbers of k(θ)∼0.17-0.4 cm(-1); and high measured decorrelation rates (τ(c)(-1)∼ω(s)∼0.5×10(6) s(-1)). Their appearance correlates with saturation of the pedestal pressure. © 2011 American Physical Society

  2. Stability of the pumpkin balloon

    Science.gov (United States)

    Baginski, Frank

    A large axisymmetric balloon with positive differential pressure, e.g., a sphere, leads to high film stresses. These can be significantly reduced by using a lobed pumpkin-like shape re-enforced with tendons. A number of schemes have been proposed to achieve a cyclically symmetric pumpkin-shape at full inflation, including the constant bulge angle (CBA) design and the constant bulge radius (CBR) design. The authors and others have carried out stability studies of CBA and CBR designs and found instabilities under various conditions. While stability seems to be a good indicator of deployment problems for large balloons under normal ascent conditions, one cannot conclude that a stable design will deploy reliably. Nevertheless, stability analysis allows one to quantify certain deployment characteristics. Ongoing research by NASA's Balloon Program Office utilizes a new design approach developed by Rodger Farley, NASA/GSFC, that takes into account film and tendon strain. We refer to such a balloon as a constant stress (CS) pumpkin design. In June 2006, the Flight 555-NT balloon (based on a hybrid CBR/CBA design) developed an S-cleft and did not deploy. In order to understand the S-cleft phenomena and study a number of aspects related to the CS-design, a series of inflation tests were conducted at TCOM, Elizabeth City, NC in 2007. The test vehicles were 27 meter diameter pumpkins distinguished by their respective equatorial bulge angles (BA). For example, BA98 indicates an equatorial bulge angle of 98° . BA90, BA55, and BA00 are similarly defined. BA98 was essentially a one-third scale version of of the Flight 555 balloon (i.e., 12 micron film instead of 38.1 micron, mini-tendons, etc.). BA90 and BA55 were Farley CS-designs. BA00 was derived from the BA55 design so that a flat chord spanned adjacent tendons. In this paper, we will carry out stability studies of BA98, BA90, BA55, and BA00. We discuss the deployment problem of pumpkin balloons in light of 2007 inflation

  3. Status of the NASA Balloon Program

    Science.gov (United States)

    Needleman, H. C.; Nock, R. S.; Bawcom, D. W.

    1993-02-01

    In the early 1980's the U.S. National Aeronautics and Space Administration (NASA) Balloon Program was faced with a problem of catastrophic balloon failures. In 1986 a balloon recovery program was initiated. This program included qualification of new balloon films, and investigations into materials, processing, structures and performance of balloons. This recovery program has been very successful. To date, more than 100 balloons manufactured of newly developed films have been flown with unprecedented success. There has been much progress made across the spectrum of balloon related disciplines. A new design philosophy has been developed and is being used for all NASA balloons. An updated balloon reliability and quality assurance program is in effect. The long duration balloon development project has been initiated with the first flight test having been conducted in December 1989 from Antarctica. A comprehensive research and development (R&D) effort has been initiated and is progressing well. The progress, status and future plans for these and other aspects of the NASA program, along with a description of the comprehensive balloon R&D activity, will be presented.

  4. Scientific ballooning in India Recent developments

    Science.gov (United States)

    Manchanda, R. K.

    Established in 1971, the National Balloon Facility operated by TIFR in Hyderabad, India, is a unique facility in the country, which provides a complete solution in scientific ballooning. It is also one of its kind in the world since it combines both, the in-house balloon production and a complete flight support for scientific ballooning. With a large team working through out the year to design, fabricate and launch scientific balloons, the Hyderabad Facility is a unique centre of expertise where the balloon design, research and development, the production and launch facilities are located under one roof. Our balloons are manufactured from 100% indigenous components. The mission specific balloon design, high reliability control and support instrumentation, in-house competence in tracking, telemetry, telecommand, data processing, system design and mechanics is its hallmark. In the past few years, we have executed a major programme of upgradation of different components of balloon production, telemetry and telecommand hardware and various support facilities. This paper focuses on our increased capability of balloon production of large sizes up to 780,000 m 3 using Antrix film, development of high strength balloon load tapes with the breaking strength of 182 kg, and the recent introduction of S-band telemetry and a commandable timer cut-off unit in the flight hardware. A summary of the various flights conducted in recent years will be presented along with the plans for new facilities.

  5. Investigation of hot air balloon fatalities.

    Science.gov (United States)

    McConnell, T S; Smialek, J E; Capron, R G

    1985-04-01

    The rising popularity of the sport of hot air ballooning has been accompanied by several recent incidents, both in this country and other parts of the world, where mechanical defects and the improper operation of balloons have resulted in several fatalities. A study was conducted to identify the location and frequency of hot air ballooning accidents. Furthermore, the study attempted to identify those accidents that were the result of improper handling on the part of the balloon operators and those that were related to specific defects in the construction of the balloon. This paper presents a background of the sport of hot air ballooning, together with an analysis of the construction of a typical hot air balloon, pointing out the specific areas where defects may occur that could result in a potential fatal balloon crash. Specific attention is given to the two recent balloon crashes that occurred in Albuquerque, N.M., hot air balloon capital of the world, and that resulted in multiple fatalities.

  6. PEBS - Positron Electron Balloon Spectrometer

    CERN Document Server

    von Doetinchem, P.; Kirn, T.; Yearwood, G.Roper; Schael, S.

    2007-01-01

    The best measurement of the cosmic ray positron flux available today was performed by the HEAT balloon experiment more than 10 years ago. Given the limitations in weight and power consumption for balloon experiments, a novel approach was needed to design a detector which could increase the existing data by more than a factor of 100. Using silicon photomultipliers for the readout of a scintillating fiber tracker and of an imaging electromagnetic calorimeter, the PEBS detector features a large geometrical acceptance of 2500 cm^2 sr for positrons, a total weight of 1500 kg and a power consumption of 600 W. The experiment is intended to measure cosmic ray particle spectra for a period of up to 20 days at an altitude of 40 km circulating the North or South Pole. A full Geant 4 simulation of the detector concept has been developed and key elements have been verified in a testbeam in October 2006 at CERN.

  7. Fluorescence Lyman-Alpha Stratospheric Hygrometer (FLASH): application on meteorological balloons, long duration balloons and unmanned aerial vehicles.

    Science.gov (United States)

    Lykov, Alexey; Khaykin, Sergey; Yushkov, Vladimir; Efremov, Denis; Formanyuk, Ivan; Astakhov, Valeriy

    The FLASH instrument is based on the fluorescent method, which uses H2O molecules photodissociation at a wavelength lambda=121.6 nm (Lalpha - hydrogen emission) followed by the measurement of the fluorescence of excited OH radicals. The source of Lyman-alpha radiation is a hydrogen discharge lamp while the detector of OH fluorescence at 308 -316 nm is a photomultiplier run in photon counting mode. The intensity of the fluorescent light as well as the instrument readings is directly proportional to the water vapor mixing ratio under stratospheric conditions with negligible oxygen absorption. Initially designed for rocket-borne application, FLASH has evolved into a light-weight balloon sonde (FLASH-B) for measurements in the upper troposphere and stratosphere on board meteorological and small plastic balloons. This configuration has been used in over 100 soundings at numerous tropical mid-latitude and polar locations within various international field campaigns. An airborne version of FLASH instrument is successfully utilized onboard stratospheric M55-Geophysica aircraft and tropospheric airborne laboratory YAK42-Roshydromet. The hygrometer was modified for application onboard stratospheric long-duration balloons (FLASH-LDB version). This version was successfully used onboard CNES super-pressure balloon launched from SSC Esrange in March 2007 and flown during 10 days. Special design for polar long duration balloon PoGOLite was created for testing work during polar day in June 2013. Installation and measurement peculiarities as well as observational results are presented. Observations of water vapour using FLASH-B instrument, being of high quality are rather costly as the payload recovery is often complicated and most of the time impossible. Following the goal to find a cost-efficient solution, FLASH was adapted for use onboard Unmanned Aerial Vehicles (UAV). This solution was only possible thanks to compactness and light-weight (0.5 kg) of FLASH instrument. The

  8. Left ventricular apical ballooning syndrome

    International Nuclear Information System (INIS)

    Rahman, N.; Tai, J.; Soofi, A.

    2007-01-01

    The transient left ventricular apical ballooning syndrome, also known as Takotsubo cardiomyopathy, is characterized by transient left ventricular dysfunction in the absence of obstructive epicardial coronary disease. Although the syndrome has been reported in Japan since 1990, it is rare in other regions. Rapid recognition of the syndrome can modify the diagnostic and therapeutic attitude i.e. avoiding thrombolysis and performing catheterization in the acute phase. (author)

  9. Viscoelastic behaviour of pumpkin balloons

    Science.gov (United States)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    2008-11-01

    The lobes of the NASA ULDB pumpkin-shaped super-pressure balloons are made of a thin polymeric film that shows considerable time-dependent behaviour. A nonlinear viscoelastic model based on experimental measurements has been recently established for this film. This paper presents a simulation of the viscoelastic behaviour of ULDB balloons with the finite element software ABAQUS. First, the standard viscoelastic modelling capabilities available in ABAQUS are examined, but are found of limited accuracy even for the case of simple uniaxial creep tests on ULDB films. Then, a nonlinear viscoelastic constitutive model is implemented by means of a user-defined subroutine. This approach is verified by means of biaxial creep experiments on pressurized cylinders and is found to be accurate provided that the film anisotropy is also included in the model. A preliminary set of predictions for a single lobe of a ULDB is presented at the end of the paper. It indicates that time-dependent effects in a balloon structure can lead to significant stress redistribution and large increases in the transverse strains in the lobes.

  10. Abdominal cavity balloon for preventing a patient's bleeding

    OpenAIRE

    Naber, E.E.H.; Rutten, H.J.T.; Jakimowicz, J.J.; Goossens, R.H.M.; Moes, C.C.M.; Buzink, S.N.

    2007-01-01

    The invention relates to an abdominal cavity balloon for preventing a haemorrhage in a patient's pelvic region, comprising an inflatable balloon, wherein the balloon is pro vided with a smooth surface and with a strip that is flex- urally stiff and formed to follow the balloon's shape for po sitioning the balloon.

  11. Turbulence fluxes and variances measured with a sonic anemometer mounted on a tethered balloon

    Science.gov (United States)

    Canut, Guylaine; Couvreux, Fleur; Lothon, Marie; Legain, Dominique; Piguet, Bruno; Lampert, Astrid; Maurel, William; Moulin, Eric

    2016-09-01

    This study presents the first deployment in field campaigns of a balloon-borne turbulence probe, developed with a sonic anemometer and an inertial motion sensor suspended below a tethered balloon. This system measures temperature and horizontal and vertical wind at high frequency and allows the estimation of heat and momentum fluxes as well as turbulent kinetic energy in the lower part of the boundary layer. The system was validated during three field experiments with different convective boundary-layer conditions, based on turbulent measurements from instrumented towers and aircraft.

  12. Vertical sounding balloons for stratospheric photochemistry

    Science.gov (United States)

    Pommereau, J. P.

    The use of vertical sounding balloons for stratospheric photochemistry studies is illustrated by the use of a vertical piloted gas balloon for the search of NO2 diurnal variations. It is shown that the use of montgolfieres (hot air balloons) can enhance the vertical sounding technique. Particular attention is given to a sun-heated montgolfiere and to the more sophisticated infrared montgolfiere that is able to perform three to four vertical excursions per day and to remain aloft for weeks or months.

  13. Gravity wave spectra in the lower stratosphere diagnosed from project loon balloon trajectories

    Science.gov (United States)

    Schoeberl, M. R.; Jensen, E.; Podglajen, A.; Coy, L.; Lodha, C.; Candido, S.; Carver, R.

    2017-08-01

    Project Loon has been launching superpressure balloons since January 2013 to provide worldwide Internet coverage. These balloons typically fly between 18 and 21 km and provide measurements of winds and pressure fluctuations in the lower stratosphere. We divide 1560 Loon flights into 3405 two-day segments for gravity wave analysis. We derive the kinetic energy spectrum from the horizontal balloon motion and estimate the temperature perturbation spectrum (proportional to the potential energy spectrum) from the pressure variations. We fit the temperature (and kinetic energy) data to the functional form T'2 = T'o2[ω/ωο)α, where ω is the wave frequency, ωο is daily frequency, T'o is the base temperature amplitude, and α is the spectral slope. Both the kinetic energy and temperature spectra show -1.9 ± 0.2 power-law dependence in the intrinsic frequency window 3-50 cycles/day. The temperature spectrum slope is weakly anticorrelated with the base temperature amplitude. We also find that the wave base temperature distribution is highly skewed. The tropical modal temperature is 0.77 K. The highest amplitude waves occur over the mountainous regions, the tropics, and the high southern latitudes. Temperature amplitudes show little height variation over our 18-21 km domain. Our results are consistent with other limited superpressure balloon analyses. The modal temperature is higher than the temperature currently used in high-frequency gravity wave parameterizations.

  14. Titan Balloon Convection Model, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This innovative research effort is directed at determining, quantitatively, the convective heat transfer coefficients applicable to a Montgolfiere balloon operating...

  15. NASA Langley Research Center tethered balloon systems

    Science.gov (United States)

    Owens, Thomas L.; Storey, Richard W.; Youngbluth, Otto

    1987-01-01

    The NASA Langley Research Center tethered balloon system operations are covered in this report for the period of 1979 through 1983. Meteorological data, ozone concentrations, and other data were obtained from in situ measurements. The large tethered balloon had a lifting capability of 30 kilograms to 2500 meters. The report includes descriptions of the various components of the balloon systems such as the balloons, the sensors, the electronics, and the hardware. Several photographs of the system are included as well as a list of projects including the types of data gathered.

  16. Excitation of high frequency pressure driven modes in non-axisymmetric equilibrium at high βpol in PBX-M

    Science.gov (United States)

    Sesnic, S.; Holland, A.; Kaita, R.; Kaye, S. M.; Okabayashi, M.; Takahashi, H.; Asakura, N.; Bell, R. E.; Bernabei, S.; Chance, M. S.; Duperrex, P.-A.; Fonck, R. J.; Gammel, G. M.; Greene, G. J.; Hatcher, R. E.; Jardin, S. C.; Jiang, T.; Kessel, C. E.; Kugel, H. W.; Leblanc, B.; Levinton, F. M.; Manickam, J.; Ono, M.; Paul, S. F.; Powell, E. T.; Qin, Y.; Roberts, D. W.; Sauthoff, N. R.

    1993-12-01

    High frequency pressure driven modes have been observed in high poloidal beta discharges in the Princeton Beta Experiment Modification (PBX-M). These modes are excited in a non-axisymmetric equilibrium characterized by a large, low frequency mt = 1/nt = 1 island, and they are capable of expelling fast ions. The modes reside on or very close to the q = 1 surface and have mode numbers with either mh = nh or (less probably) mh/nh = mh/(mh-1), with mh varying between 3 and 10. Occasionally these modes are simultaneously localized in the vicinity of the ml = 2/nl = 1 island. The high frequency modes near the q = 1 surface also exhibit a ballooning character, being significantly stronger on the large major radius side of the plasma. When a large mt = 1/nt = 1 island is present, the mode is poloidally localized in the immediate vicinity of the X point of the island. The modes occur exclusively in high beta beam heated discharges and are likely to be driven by the beam ions. They can thus be a manifestation of either a toroidicity induced shear Alfven eigenmode (TAE) at q = (2mh+1)/2nh, a kinetic ballooning mode, or some other type of pressure driven (high β) mode. Most of the data are consistent with the theoretical predictions for the TAE gap mode. Since the high frequency modes in PBX-M, however, are found exclusively on or in the immediate neighbourhood of magnetic surfaces with low rational numbers (q = 1, 2,...), other possibilities are not excluded

  17. Balloon dilatations of esophageal strictures

    International Nuclear Information System (INIS)

    Seo, Jeong Jin; Juhng, Seon Kwan; Kim, Jae Kyu; Chung, Hyon De

    1990-01-01

    Most benign esophageal strictures can be successfully dilated with conventional bougienage technique. But occasionally strictures are so tight, lengthy, or sometimes irregular that this technique fail, and surgical intervention is required. Since 1974 Gruentzig balloon catheter has succeed when used for strictures in the cardiac and peripheral vasculatures, the biliary and urinary tracts, the colon of neonates after inflammatory disease and also in the esophagus. Fluoroscopically guided balloon catheters were used to dilate 30 esophageal strictures in 30 patients over 3 years at Department of Diagnostic Radiology, Chonnam University, College of Medicine. The distribution of age was from 7 years to 71 days and the ratio of male to female was 15:15. The causes of benign stricture (23 cases) were post-operative strictures (13), chemical (4), achalasia (3), chronic inflammation (2), esophageal rupture (1) and those of malignant stricture (7 cases) were post-radiation stricture of primary esophageal cancer (6) and metastatic esophageal cancer (1). The success rate of procedure was 93% (28/30). The causes of failure were the failure of passage of stricture due to markedly dilated proximal segment of esophagus (1 case) and too long segment of stricture (1 case). Complication of procedure was the diverticular-formation of esophagus in 3 cases, but has no clinical significance in follow-up esophagography. In conclusion, fluoroscopically guided balloon dilation of esophageal stricture appears to be safe, effective treatment and may be have theoretical advantages over conventional bougienage and also should be considered before other methods of treatment are used

  18. Balloon dilatations of esophageal strictures

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jeong Jin; Juhng, Seon Kwan; Kim, Jae Kyu; Chung, Hyon De [Chonnam National University College of Medicine, Seoul (Korea, Republic of)

    1990-04-15

    Most benign esophageal strictures can be successfully dilated with conventional bougienage technique. But occasionally strictures are so tight, lengthy, or sometimes irregular that this technique fail, and surgical intervention is required. Since 1974 Gruentzig balloon catheter has succeed when used for strictures in the cardiac and peripheral vasculatures, the biliary and urinary tracts, the colon of neonates after inflammatory disease and also in the esophagus. Fluoroscopically guided balloon catheters were used to dilate 30 esophageal strictures in 30 patients over 3 years at Department of Diagnostic Radiology, Chonnam University, College of Medicine. The distribution of age was from 7 years to 71 days and the ratio of male to female was 15:15. The causes of benign stricture (23 cases) were post-operative strictures (13), chemical (4), achalasia (3), chronic inflammation (2), esophageal rupture (1) and those of malignant stricture (7 cases) were post-radiation stricture of primary esophageal cancer (6) and metastatic esophageal cancer (1). The success rate of procedure was 93% (28/30). The causes of failure were the failure of passage of stricture due to markedly dilated proximal segment of esophagus (1 case) and too long segment of stricture (1 case). Complication of procedure was the diverticular-formation of esophagus in 3 cases, but has no clinical significance in follow-up esophagography. In conclusion, fluoroscopically guided balloon dilation of esophageal stricture appears to be safe, effective treatment and may be have theoretical advantages over conventional bougienage and also should be considered before other methods of treatment are used.

  19. GRAINE balloon experiment in 2015

    Directory of Open Access Journals (Sweden)

    Rokujo Hiroki

    2017-01-01

    Full Text Available Observations of cosmic gamma rays are important for studying high energy phenomena in the universe. Since 2008, the Large Area Telescope on the Fermi satellite has surveyed the whole gamma-ray sky in the sub-GeV/GeV energy region, and accumurated a large amount of data. However, observations at the low galactic latitude remains difficult because of a lack of angular resolution, increase of background flux originating from galactic diffuse gamma rays, etc. The Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE is a gamma-ray observation project with a new balloon-borne emulsion gamma-ray telescope. Nuclear emulsion is a high-resolution 3D tracking device. It determines the incident angle with 0.1∘ resolution for 1 GeV gamma rays (1.0∘ for 100 MeV, and has linear polarization sensitivity. GRAINE aims at precise observation of gamma-ray sources, especially in the galactic plane, by repeating long-duration balloon flights with large-aperture-area (10 m2 high-resolution emulsion telescopes. In May 2015, we performed a balloon-borne experiment in Alice Springs, Australia, in order to demonstrate the imaging performance of our telescope. The emulsion telescope that has an aperture area of 0.4 m2 was employed in this experiment. It observed the Vela pulsar (the brightest gamma-ray source in the GeV sky at an altitude of 37 km for 6 hours out of the flight duration of 14 hours. In this presentation, we will report the latest results and the status of the GRAINE project.

  20. The role of flow shear in the ballooning stability of tokamak transport barriers

    International Nuclear Information System (INIS)

    Webster, A.J.; Wilson, H.R.; Scaife, A.M.M.

    2004-01-01

    A tokamak's economic performance is strongly affected by the plasma pressure that it may sustain, which in turn is limited by the maximum pressure gradients that may be supported. Ballooning modes are typically driven unstable by increasing the pressure gradient, and because they can radially extend across many rational surfaces, they can seriously reduce a plasma's energy confinement. Here an eigenmode formulation is used to study the stability of ballooning modes in internal transport barriers ('ITBs'), in which very strong pressure gradients and flow shears may be found. This extends previous studies that used an 'eikonal' formulation, as it enables the study of: ballooning modes with a finite toroidal mode-number n (finite wavelength perpendicular to the magnetic field), to find new solution branches, to obtain the eigenmode structures, and to investigate the effects of a radially varying equilibrium. The structure of a finite n ballooning mode in flow shear is found to be significantly affected by a radially varying equilibrium, and at low flow shears the growth rates are increased above those of modes studied in the limit of n→∞. The different solution branches can couple as the flow shear is increased, leading to a pair of asymmetric mode structures with complex conjugate growth rates. These effects are shown to be a consequence of the mode trying to localize at the most unstable radial location, and its desire to rotate with the flow. In addition, closer to marginal stability a sufficiently strong flow-shear can (at least for some cases), destabilize a previously stable mode

  1. PB3D : a new code for 3D ideal linear peeling-ballooning stability

    NARCIS (Netherlands)

    Weyens, T.; Sanchez, R.; Huijsmans, G.; Garcia, L.; Loarte, A.

    2015-01-01

    Ideal peeling-ballooning modes are important for magnetic nuclear fusion devices, but most of the theoretical and computational work that has been performed over the years to gain insight into their inner workings and consequences has been limited to axisymmetric (so-called 2D) cases which limits

  2. Influence of Equilibrium Perpendicular Shear Flow on Peeling-ballooning Instabilities

    Science.gov (United States)

    Xi, P. W.; Xu, X. Q.

    2011-10-01

    The influence of perpendicular ExB shear flow on peeling-ballooning instabilities is investigated with BOUT++ code. In our simulation, a set of reduced MHD equations are solved for a very unstable equilibrium and a marginal unstable equilibrium in shifted-circular tokamak geometry. For ideal MHD cases without diamagnetic terms and resistivity, we find that flow shear shows dramatic stabilizing effect on peeling-ballooning modes and the stabilizing degree increases with mode number. When the flow shear is large enough, we find the curvature of growth rate verse mode number has the same shape like that for the case with only diamagnetic term, and this implies that diamagnetic term and the shear flow have the same mechanism acting on peeling-ballooning instabilities. The role of Kelvin-Helmholtz term is also investigated and we find it is destabilizing and the effect depends on both flow shear and mode number. For cases with both diamagnetic term and the applied shear flow, modes with intermediate mode number are strongest stabilized while high n and low n mode keep unstable. Based on these results, an ELM trigger sketch is proposed. Performed for USDoE by LLNL Contract DE-AC52-07NA27344.

  3. Advances in measurement and modeling of the high-confinement-mode pedestal on the Alcator C-Mod tokamak

    International Nuclear Information System (INIS)

    Hughes, J.W.; LaBombard, B.; Mossessian, D.A.; Hubbard, A.E.; Terry, J.; Biewer, T.

    2006-01-01

    Edge transport barrier (ETB) studies on the Alcator C-Mod tokamak [Phys. Plasmas 1, 1511 (1994)] investigate pedestal scalings and the radial transport of plasma and neutrals. Pedestal profiles show trends with plasma operational parameters such as total current I P . A ballooning-like I P 2 dependence is seen in the pressure gradient, despite calculated stability to ideal ballooning modes. A similar scaling is seen in the near scrape-off layer for both low-confinement (L-mode) and H-mode discharges, possibly due to electromagnetic fluid drift turbulence setting transport near the separatrix. Neutral density diagnosis allows an examination of D 0 fueling in H-modes, yielding profiles of effective particle diffusivity in the ETB, which vary as I P is changed. Edge neutral transport is studied using a one-dimensional kinetic treatment. In both experiment and modeling, the C-Mod density pedestal exhibits a weakly increasing pedestal density and a nearly invariant density pedestal width as the D 0 source rate increases. Identical modeling performed on pedestal profiles typical of DIII-D [Nucl. Fusion 42, 614 (2002)] reveal differences in pedestal scalings qualitatively similar to experimental results

  4. Balloon dilatation of iatrogenic urethral strictures

    International Nuclear Information System (INIS)

    Acunas, B.; Acunas, G.; Gokmen, E.; Celik, L.

    1988-01-01

    Balloon dilatation of the urethra was performed in five patients with iatrogenic urethral strictures. The urethral strictures were successfully negotiated and dilated in all patients. Redilatation became necessary in a period ranging from 3 to 10 months. The authors believe that balloon dilatation of the urethra can be safely and successfully performed; the procedure produces minimal trauma and immediate relief of symptoms. (orig.)

  5. Paraplegia following intraaortic balloon circulatory assistance

    Directory of Open Access Journals (Sweden)

    Benício Anderson

    1999-01-01

    Full Text Available Intraaortic balloon counterpulsation is frequently used in patients experiencing severe ventricular dysfunction following maximal drug therapy. However, even with the improvement of percutaneous insertion techniques, the procedure has always been followed by vascular, infectious, and neurological complications. This article describes a case of paraplegia due to intraaortic balloon counterpulsation in the postoperative period of cardiac surgery.

  6. Montgolfiere balloon missions from Mars and Titan

    Science.gov (United States)

    Jones, Jack A.

    2005-01-01

    Montgolfieres, which are balloons that are filled with heated ambient atmospheric gas, appear promising for the exploration of Mars as well as of Saturn's moon, Titan. On Earth, Montgolfieres are also known as 'hot air balloons'. Commercial versions are typically heated by burning propane, although a number of radiant and solar-heated Montgolfieres have been flown on earth by CNES.

  7. BURNING PLASMA PROJECTIONS USING DRIFT WAVE TRANSPORT MODELS AND SCALINGS FOR THE H-MODE PEDESTAL

    International Nuclear Information System (INIS)

    KINSEY, J.E.; ONJUN, T.; BATEMAN, G.; KRITZ, A.; PANKIN, A.; STAEBLER, G.M.; WALTZ, R.E.

    2002-01-01

    OAK-B135 The GLF23 and Multi-Mode (MM95) transport models are used along with a model for the H-mode pedestal to predict the fusion performance for the ITER, FIRE, and IGNITOR tokamak designs. The drift-wave predictive transport models reproduce the core profiles in a wide variety of tokamak discharges, yet they differ significantly in their response to temperature gradient (stiffness). Recent gyro-kinetic simulations of ITG/TEM and ETG modes motivate the renormalization of the GLF23 model. The normalizing coefficients for the ITG/TEM modes are reduced by a factor of 3.7 while the ETG mode coefficient is increased by a factor of 4.8 in comparison with the original model. A pedestal temperature model is developed for type I ELMy H-mode plasmas based on ballooning mode stability and a theory-motivated scaling for the pedestal width. In this pedestal model, the pedestal density is proportional to the line-averaged density and the pedestal temperature is inversely related to the pedestal density

  8. Technologies developed by CNES balloon team

    Science.gov (United States)

    Sosa-Sesma, Sergio; Charbonnier, Jean-Marc; Deramecourt, Arnaud

    CNES balloon team develops and operates all the components of this kind of vehicle: it means envelope and gondola. This abstract will point out only developments done for envelope. Nowadays CNES offers to scientists four types of envelops that cover a large range of mission demands. These envelops are: 1. Zero pressure balloons: Size going from 3,000m3 to 600,000m3, this kind of envelop is ideal for short duration flights (a few hours) but if we use an intelligent management of ballast consumption and if we chose the best launch site, it is possible to perform medium duration flights (10/20 days depending on the ballast on board). Flight train mass starts at 50kg for small balloons and reach 1000kg for larger ones. Zero pressure balloons are inflated with helium gas. 2. Super pressure balloons: Diameter going from 2.5m to 12m, this kind of envelop is ideal for long duration flights (1 to 6 months). Flight train is inside the envelop for small balloons, it means 2.5 diameter meters which is usually called BPCL (Super pressure balloon for Earth boundary layer) and it is about 3kg of mass. Larger ones could lift external flight trains about 50kg of mass. Super pressure balloons are inflated with helium gas. 3. MIR balloons: Size going from 36,000m3 to 46,000m3. Ceiling is reach with helium gas but after three days helium is no longer present inside and lift force is produced by difference of temperature between air inside and air of atmosphere. Flight trains must not be over 50kg. 4. Aero Clipper balloons: A concept to correlate measurements done in oceans and in nearest layers of atmosphere simultaneously. Flight train is made by a "fish" that drags inside water and an atmospheric gondola few meters above "fish", both pushed by a balloon which profits of the wind force. Materials used for construction and assembling depend on balloon type; they are usually made of polyester or polyethylene. Thickness varies from 12 micrometers to 120 micrometers. Balloon assembling

  9. Recent Developments in Scientific Research Ballooning

    International Nuclear Information System (INIS)

    Jones, W. Vernon

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Balloon Program is committed to meeting the need for extended duration scientific investigations by providing advanced balloon vehicles and support systems. A sea change in ballooning capability occurred with the inauguration of 8 - 20 day flights around Antarctica in the early 1990's. The attainment of 28-31 day flights and a record-breaking 42-day flight in, respectively, two and three circumnavigations of the continent has greatly increased the expectations of the scientific users. A new super-pressure balloon is currently under development for future flights of 60-100 days at any latitude, which would bring another sea change in scientific research ballooning

  10. Early Cosmic Ray Research with Balloons

    Energy Technology Data Exchange (ETDEWEB)

    Walter, Michael, E-mail: michael.walter@desy.de

    2013-06-15

    The discovery of cosmic rays by Victor Hess during a balloon flight in 1912 at an altitude of 5350 m would not have been possible without the more than one hundred years development of scientific ballooning. The discovery of hot air and hydrogen balloons and their first flights in Europe is shortly described. Scientific ballooning was mainly connected with activities of meteorologists. It was also the geologist and meteorologist Franz Linke, who probably observed first indications of a penetrating radiation whose intensity seemed to increase with the altitude. Karl Bergwitz and Albert Gockel were the first physicists studying the penetrating radiation during balloon flights. The main part of the article deals with the discovery of the extraterrestrial radiation by V. Hess and the confirmation by Werner Kolhörster.

  11. Early Cosmic Ray Research with Balloons

    Science.gov (United States)

    Walter, Michael

    2013-06-01

    The discovery of cosmic rays by Victor Hess during a balloon flight in 1912 at an altitude of 5350 m would not have been possible without the more than one hundred years development of scientific ballooning. The discovery of hot air and hydrogen balloons and their first flights in Europe is shortly described. Scientific ballooning was mainly connected with activities of meteorologists. It was also the geologist and meteorologist Franz Linke, who probably observed first indications of a penetrating radiation whose intensity seemed to increase with the altitude. Karl Bergwitz and Albert Gockel were the first physicists studying the penetrating radiation during balloon flights. The main part of the article deals with the discovery of the extraterrestrial radiation by V. Hess and the confirmation by Werner Kolhörster.

  12. Early Cosmic Ray Research with Balloons

    International Nuclear Information System (INIS)

    Walter, Michael

    2013-01-01

    The discovery of cosmic rays by Victor Hess during a balloon flight in 1912 at an altitude of 5350 m would not have been possible without the more than one hundred years development of scientific ballooning. The discovery of hot air and hydrogen balloons and their first flights in Europe is shortly described. Scientific ballooning was mainly connected with activities of meteorologists. It was also the geologist and meteorologist Franz Linke, who probably observed first indications of a penetrating radiation whose intensity seemed to increase with the altitude. Karl Bergwitz and Albert Gockel were the first physicists studying the penetrating radiation during balloon flights. The main part of the article deals with the discovery of the extraterrestrial radiation by V. Hess and the confirmation by Werner Kolhörster

  13. Mode of action based risk assessment of the botanical food-borne alkenylbenzene apiol from parsley using physiologically based kinetic (PBK) modelling and read-across from safrole

    NARCIS (Netherlands)

    Alajlouni, A.M.; Al-Malahmeh, A.J.; Kiwamoto, Reiko; Wesseling, Sebastiaan; Soffers, A.E.M.F.; Al-Subeihi, A.A.A.; Vervoort, Jacques; Rietjens, I.M.C.M.

    2016-01-01

    The present study developed physiologically-based kinetic (PBK) models for the alkenylbenzene apiol in order to facilitate risk assessment based on read-across from the related alkenylbenzene safrole. Model predictions indicate that in rat liver the formation of the 1'-sulfoxy metabolite is about

  14. Maximum β limited by ideal MHD ballooning instabilites in JT-60

    International Nuclear Information System (INIS)

    Seki, Shogo; Azumi, Masashi

    1986-03-01

    Maximum β limited by ideal MHD ballooning instabilities is investigated on divertor configurations in JT-60. Maximum β against ballooning modes in JT-60 has strong dependecy on the distribution of the safety factor over the magnetic surfaces. Maximum β is ∼ 2 % for q 0 = 1.0, while more than 3 % for q 0 = 1.5. These results suggest that the profile control of the safety factor, especially on the magnetic axis, is attractive to the higher β operation in JT-60. (author)

  15. Esophageal achalasia : results of balloon dilation

    Energy Technology Data Exchange (ETDEWEB)

    Ki, Won Woo; Kang, Sung Gwon; Yoon, Kwon Ha; Kim, Nam Hyeon; Lee, Hyo Jeong; Yoon, Hyun Ki; Sung, Kyu Bo; Song, Ho Young [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-08-01

    To evaluate the clinical effectiveness of fluoroscopically guided balloon dilation in the treatment of esophageal achalasia. Under fluoroscopic guidance, 21 balloon dilation procedures were performed in 14 patients with achalasia. A balloon with a diameter of 20 mm was used for the initial attempt.If the patient tolerated this well, the procedure was repeated with a 10-20 mm balloon, placed alongside at the same session. If, however the patient complained of severe chest pain and/or a postprocedural esophagogram showed an improvement,the additional balloon was not used. For patients whose results were unsatisfactory, the dilation procedure was repeated at sessions three to seven days apart. Succesful dilation was achieved in 13 of 14 patients(92.9%), who needed a total of 20 sessions of balloon dilation, ranging from one to three sessions per patient(mean, 1.54 sessions). Esophageal rupture occured in one of 14 patients(7.1%) ; of the 13 patients who underwent a successful dilation procedure, 12(92.3%) were free of recurrent symptoms during the follow-up period of 1-56(mean, 18.5) months. The remaning patient(7.7%) had a recurrence seven months after dilation. Fluoroscopically guided balloon dilation seems to be safe and effective in the treatment of esophageal achalasia.

  16. Esophageal achalasia : results of balloon dilation

    International Nuclear Information System (INIS)

    Ki, Won Woo; Kang, Sung Gwon; Yoon, Kwon Ha; Kim, Nam Hyeon; Lee, Hyo Jeong; Yoon, Hyun Ki; Sung, Kyu Bo; Song, Ho Young

    1996-01-01

    To evaluate the clinical effectiveness of fluoroscopically guided balloon dilation in the treatment of esophageal achalasia. Under fluoroscopic guidance, 21 balloon dilation procedures were performed in 14 patients with achalasia. A balloon with a diameter of 20 mm was used for the initial attempt.If the patient tolerated this well, the procedure was repeated with a 10-20 mm balloon, placed alongside at the same session. If, however the patient complained of severe chest pain and/or a postprocedural esophagogram showed an improvement,the additional balloon was not used. For patients whose results were unsatisfactory, the dilation procedure was repeated at sessions three to seven days apart. Succesful dilation was achieved in 13 of 14 patients(92.9%), who needed a total of 20 sessions of balloon dilation, ranging from one to three sessions per patient(mean, 1.54 sessions). Esophageal rupture occured in one of 14 patients(7.1%) ; of the 13 patients who underwent a successful dilation procedure, 12(92.3%) were free of recurrent symptoms during the follow-up period of 1-56(mean, 18.5) months. The remaning patient(7.7%) had a recurrence seven months after dilation. Fluoroscopically guided balloon dilation seems to be safe and effective in the treatment of esophageal achalasia

  17. Heat Transfer Model for Hot Air Balloons

    Science.gov (United States)

    Llado-Gambin, Adriana

    A heat transfer model and analysis for hot air balloons is presented in this work, backed with a flow simulation using SolidWorks. The objective is to understand the major heat losses in the balloon and to identify the parameters that affect most its flight performance. Results show that more than 70% of the heat losses are due to the emitted radiation from the balloon envelope and that convection losses represent around 20% of the total. A simulated heating source is also included in the modeling based on typical thermal input from a balloon propane burner. The burner duty cycle to keep a constant altitude can vary from 10% to 28% depending on the atmospheric conditions, and the ambient temperature is the parameter that most affects the total thermal input needed. The simulation and analysis also predict that the gas temperature inside the balloon decreases at a rate of -0.25 K/s when there is no burner activity, and it increases at a rate of +1 K/s when the balloon pilot operates the burner. The results were compared to actual flight data and they show very good agreement indicating that the major physical processes responsible for balloon performance aloft are accurately captured in the simulation.

  18. Accurate Determination of the Volume of an Irregular Helium Balloon

    Science.gov (United States)

    Blumenthal, Jack; Bradvica, Rafaela; Karl, Katherine

    2013-01-01

    In a recent paper, Zable described an experiment with a near-spherical balloon filled with impure helium. Measuring the temperature and the pressure inside and outside the balloon, the lift of the balloon, and the mass of the balloon materials, he described how to use the ideal gas laws and Archimedes' principal to compute the average molecular…

  19. Looners: Inside the world of balloon fetishism

    OpenAIRE

    McIntyre, Karen E

    2011-01-01

    In the spring of 1997, Shaun had just broken up with a boyfriend, and his roommate had moved out. Living alone for the first time and relieved of the fear that someone might walk in the door, he was finally able to indulge his fantasy. The young man sat on his couch and started blowing up balloons. Shaun had loved playing with balloons since he was a child. When he hit puberty, he felt his first orgasm rubbing against a balloon. It was then that his relationship with the object took ...

  20. Heat Transfer Model for Hot Air Balloons

    OpenAIRE

    Lladó Gambín, Adriana

    2016-01-01

    A heat transfer model and analysis for hot air balloons is presented in this work, backed with a flow simulation using SolidWorks. The objective is to understand the major heat losses in the balloon and to identify the parameters that affect most its flight performance. Results show that more than 70% of the heat losses are due to the emitted radiation from the balloon envelope and that convection losses represent around 20% of the total. A simulated heating source is also included in the mod...

  1. Multi-scale-nonlinear interactions among macro-MHD mode, micro-turbulence, and zonal flow

    International Nuclear Information System (INIS)

    Ishizawa, Akihiro; Nakajima, Noriyoshi

    2007-01-01

    This is the first numerical simulation demonstrating that macro-magnetohydrodynamic (macro-MHD) mode is exited as a result of multi-scale interaction in a quasi-steady equilibrium formed by a balance between zonal flow and micro-turbulence via reduced-two-fluid simulation. Only after obtaining the equilibrium which includes zonal flow and the turbulence caused by kinetic ballooning mode is this simulation of macro-MHD mode, double tearing mode, accomplished. In the quasi-steady equilibrium a macro-fluctuation which has the same helicity as that of double tearing mode is a part of the turbulence until it grows as a macro-MHD mode finally. When the macro-MHD grows it effectively utilize free energy of equilibrium current density gradient because of positive feedback loop between suppression of zonal flow and growth of the macro-fluctuation causing magnetic reconnection. Thus once the macro-MHD grows from the quasi-equilibrium, it does not go back. This simulation is more comparable with experimental observation of growing macro-fluctuation than traditional MHD simulation of linear instabilities in a static equilibrium. (author)

  2. Retained intraaortic balloon. Case report and review of the literature.

    Science.gov (United States)

    Grande, A M; Martinelli, L; Graffigna, A; Viganò, M

    1995-01-01

    We report a case of intraaortic balloon entrapment in a 70-year-old man who underwent emergency triple coronary bypass. Intraaortic balloon rupture caused the formation of a clot inside the balloon that eventually was responsible for the balloon's entrapment at the aortic bifurcation. The patient had severe atherosclerosis of the aorta and iliac arteries. Balloon removal required aorto-iliac exposure and aorto-bifemoral bypass. After 16 months, he is symptom free and at home.

  3. Solid State Inflation Balloon Active Deorbiter

    Data.gov (United States)

    National Aeronautics and Space Administration — The Solid State Inflation Balloon (SSIB) is a simple, reliable, low-cost, non-propulsive system for deliberate deorbit and control of downrange point-of-impact that...

  4. Deployment Instabilities of Lobed-Pumpkin Balloon

    Science.gov (United States)

    Nakashino, Kyoichi

    A lobed-pumpkin balloon, currently being developed in ISAS/JAXA as well as in NASA, is a promising vehicle for long duration scientific observations in the stratosphere. Recent ground and flight experiments, however, have revealed that the balloon has deployment instabilities under certain conditions. In order to overcome the instability problems, a next generation SPB called 'tawara' type balloon has been proposed, in which an additional cylindrical part is appended to the standard lobed-pumpkin balloon. The present study investigates the deployment stability of tawara type SPB in comparison to that of standard lobed-pumpkin SPB through eigenvalue analysis on the basis of finite element methods. Our numerical results show that tawara type SPB enjoys excellent deployment performance over the standard lobed-pumpkin SPBs.

  5. Gigantic balloon type artificial lightning generator

    Energy Technology Data Exchange (ETDEWEB)

    Horii; kenji

    1988-09-05

    This paper outlines a hot-air balloon type Van de Graaf 50-MV generator which can generate a 50,000,000 V, 0.2 to 0.3 coulomb artificial lightning comparable to natural lightning discharge and reports the results of investigation on discharging experiments conducted using this apparatus. The subjects covered are as follows: (1) Outline of the hot-air balloon type Van de Graaf 50-MV generator, (2) electric characteristics of the Van de Graaf 50-MV generator, (3) charge transfer with film and balloon charging, (4) the load of the balloon and buoyancy calculation, (5) leakage of charges, (6) study of charging experiments, and (7) evaluation of the apparatus and its method and problems to be solved. (4 figs, 4 tabs, 4 refs)

  6. The UK sounding rocket and balloon programme

    International Nuclear Information System (INIS)

    Delury, J.T.

    1980-01-01

    The UK civil science balloon and rocket programmes for 1979/80/81 are summarised and the areas of scientific interest for the period 1981/85 mentioned. In the main the facilities available are 10 in number balloons up to 40 m cu ft launched from USA or Australia and up to 10 in number 7 1/2'' diameter Petrel rockets. This paper outlines the 1979 and 1980 programmes and explains the longer term plans covering the next 5 years. (Auth.)

  7. Test ventilation with smoke, bubbles, and balloons

    International Nuclear Information System (INIS)

    Pickering, P.L.; Cucchiara, A.L.; McAtee, J.L.; Gonzales, M.

    1987-01-01

    The behavior of smoke, bubbles, and helium-filled balloons was videotaped to demonstrate the mixing of air in the plutonium chemistry laboratories, a plutonium facility. The air-distribution patterns, as indicated by each method, were compared. Helium-filled balloons proved more useful than bubbles or smoke in the visualization of airflow patterns. The replay of various segments of the videotape proved useful in evaluating the different techniques and in identifying airflow trends responsible for air mixing. 6 refs

  8. Trace gas measurements from tethered balloon platforms

    Science.gov (United States)

    Bandy, Alan R.; Bandy, Terese L.; Youngbluth, Otto; Owens, Thomas L.

    1987-01-01

    Instrumentation and chemical sampling and analysis procedures are described for making measurements of atmospheric carbon disulfide in the concentration range 1-1000 pptv from tethered balloon platforms. Results of a study on the CS2 composition of air downward of a saltwater marsh are reported. A method for obtaining the necessary data for solving the budget equations for surface fluxes, chemical formation rates and chemical destruction rates using data acquired from tethered balloon platforms is presented.

  9. TMBM: Tethered Micro-Balloons on Mars

    Science.gov (United States)

    Sims, M. H.; Greeley, R.; Cutts, J. A.; Yavrouian, A. H.; Murbach, M.

    2000-01-01

    The use of balloons/aerobots on Mars has been under consideration for many years. Concepts include deployment during entry into the atmosphere from a carrier spacecraft, deployment from a lander, use of super-pressurized systems for long duration flights, 'hot-air' systems, etc. Principal advantages include the ability to obtain high-resolution data of the surface because balloons provide a low-altitude platform which moves relatively slowly. Work conducted within the last few years has removed many of the technical difficulties encountered in deployment and operation of balloons/aerobots on Mars. The concept proposed here (a tethered balloon released from a lander) uses a relatively simple approach which would enable aspects of Martian balloons to be tested while providing useful and potentially unique science results. Tethered Micro-Balloons on Mars (TMBM) would be carried to Mars on board a future lander as a stand-alone experiment having a total mass of one to two kilograms. It would consist of a helium balloon of up to 50 cubic meters that is inflated after landing and initially tethered to the lander. Its primary instrumentation would be a camera that would be carried to an altitude of up to tens of meters above the surface. Imaging data would be transmitted to the lander for inclusion in the mission data stream. The tether would be released in stages allowing different resolutions and coverage. In addition during this staged release a lander camera system may observe the motion of the balloon at various heights above he lander. Under some scenarios upon completion of the primary phase of TMBM operations, the tether would be cut, allowing TMBM to drift away from the landing site, during which images would be taken along the ground.

  10. Ideal ballooning stability of JET discharges

    International Nuclear Information System (INIS)

    Galvao, R.M.O.; Lazzaro, E.; O'Rourke, J.; Smeulders, P.; Schmidt, G.

    1989-01-01

    Conditions under which ballooning modes are expected to be excited have recently been obtained in two different types of discharges in JET. In the first type, discharges with β approaching the Troyon-Sykes-Wesson critical value β c for optimised pressure profiles have been produced at low toroidal fields (B T =1.5T). In the second type, extremely high pressure gradients have been produced in the plasma core through pellet injection in the current rise phase of the discharge followed by strong additional heating. The stability of these discharges has been studied with the stability code HBT coupled to the equilibrium identification code IDENTC. The equilibrium pressure and diamagnetic function profiles are determined in IDENTC by an optimisation procedure to fit the external magnetic measurements. The resulting pressure profile in the equatorial plane is then compared with the profile derived from 'direct' measurements, i.e. electron density and temperature profiles measured by the LIDAR diagnostic system, ion-temperature profile measured by the charge-exchange diagnostic system, and ion density profile calculated from the Z eff and electron density profiles. Furthermore, the value of the safety factor q on axis is compared with that determined from polarimetry. When good agreement is found, the output data from IDENTC is passed directly to HBT to carry out the stability analysis. When there is not a good agreement, as in the case of pellet discharges with highly peaked pressure profiles, the equilibrium is reevaluated using the 'experimental' profile and the data from polarimetry. (author) 6 refs., 4 figs

  11. Kinetic effects on magnetohydrodynamic phenomena

    International Nuclear Information System (INIS)

    Naito, Hiroshi; Matsumoto, Taro

    2001-01-01

    Resistive and ideal magnetohydrodynamic (MHD) theories are insufficient to adequately explain MHD phenomena in the high-temperature plasma. Recent progress in numerical simulations concerning kinetic effects on magnetohydrodynamic phenomena is summarized. The following three topics are studied using various models treating extended-MHD phenomena. (1) Kinetic modifications of internal kink modes in tokamaks with normal and reversed magnetic shear configurations. (2) Temporal evolution of the toroidal Alfven eigenmode and fishbone mode in tokamaks with energetic ions. (3) Kinetic stabilization of a title mode in field-reversed configurations by means of anchoring ions and beam ions. (author)

  12. Gondola development for CNES stratospheric balloons

    Science.gov (United States)

    Vargas, A.; Audoubert, J.; Cau, M.; Evrard, J.; Verdier, N.

    The CNES has been supporting scientific ballooning since its establishment in 1962. The two main parts of the balloon system or aerostat are the balloon itself and the flight train, comprising the house-keeping gondola, for the control of balloon flight (localization and operational telemetry & telecommand - TM/TC), and the scientific gondola with its dedicated telecommunication system. For zero pressure balloon, the development of new TM/TC system for the housekeeping and science data transmission are going on from 1999. The main concepts are : - for balloon house-keeping and low rate scientific telemetry, the ELITE system, which is based on single I2C bus standardizing communication between the different components of the system : trajectography, balloon control, power supply, scientific TM/TC, .... In this concept, Radio Frequency links are developed between the house keeping gondola and the components of the aerostat (balloon valve, ballast machine, balloon gas temperature measurements, ...). The main objectives are to simplify the flight train preparation in term of gondola testing before flight, and also by reducing the number of long electrical cables integrated in the balloon and the flight train; - for high rate scientific telemetry, the use of functional interconnection Internet Protocol (IP) in interface with the Radio Frequency link. The main idea is to use off-the-shelf IP hardware products (routers, industrial PC, ...) and IP software (Telnet, FTP, Web-HTTP, ...) to reduce the development costs; - for safety increase, the adding, in the flight train, of a totally independent house keeping gondola based on the satellite Inmarsat M and Iridium telecommunication systems, which permits to get real time communications between the on-board data mobile and the ground station, reduced to a PC computer with modem connected to the phone network. These GEO and LEO telecommunication systems give also the capability to operate balloon flights over longer distance

  13. Kinetic electromagnetic instabilities in an ITB plasma with weak magnetic shear

    Science.gov (United States)

    Chen, W.; Yu, D. L.; Ma, R. R.; Shi, P. W.; Li, Y. Y.; Shi, Z. B.; Du, H. R.; Ji, X. Q.; Jiang, M.; Yu, L. M.; Yuan, B. S.; Li, Y. G.; Yang, Z. C.; Zhong, W. L.; Qiu, Z. Y.; Ding, X. T.; Dong, J. Q.; Wang, Z. X.; Wei, H. L.; Cao, J. Y.; Song, S. D.; Song, X. M.; Liu, Yi.; Yang, Q. W.; Xu, M.; Duan, X. R.

    2018-05-01

    Kinetic Alfvén and pressure gradient driven instabilities are very common in magnetized plasmas, both in space and the laboratory. These instabilities will be easily excited by energetic particles (EPs) and/or pressure gradients in present-day fusion and future burning plasmas. This will not only cause the loss and redistribution of the EPs, but also affect plasma confinement and transport. Alfvénic ion temperature gradient (AITG) instabilities with the frequency ω_BAE<ω<ω_TAE and the toroidal mode numbers n=2{-}8 are found to be unstable in NBI internal transport barrier plasmas with weak shear and low pressure gradients, where ω_BAE and ω_TAE are the frequencies of the beta- and toroidicity-induced Alfvén eigenmodes, respectively. The measured results are consistent with the general fishbone-like dispersion relation and kinetic ballooning mode equation, and the modes become more unstable the smaller the magnetic shear is in low pressure gradient regions. The interaction between AITG activity and EPs also needs to be investigated with greater attention in fusion plasmas, such as ITER (Tomabechi and The ITER Team 1991 Nucl. Fusion 31 1135), since these fluctuations can be enhanced by weak magnetic shear and EPs.

  14. Use of monorail PTCA balloon catheter for local drug delivery.

    Science.gov (United States)

    Trehan, Vijay; Nair, Girish M; Gupta, Mohit D

    2007-01-01

    We report the use of monorail coronary balloon as an infusion catheter to give bailout abciximab selectively into the site of stent thrombosis as an adjunct to plain old balloon angioplasty (POBA) in a patient of subacute stent thrombosis of the left anterior descending coronary artery. The balloon component (polyamide material) of the monorail balloon catheter was shaved off the catheter so that abciximab injected through the balloon port of the catheter exited out the shaft of the balloon catheter at the site from where the balloon material was shaved off. We believe that selective infusion with abciximab along with POBA established antegrade flow and relieved the patient's ischemia. In the absence of essential hardware to give intracoronary drugs in an emergency situation, one may employ our technique of infusion through a monorail balloon catheter after shaving the balloon component from the catheter.

  15. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  16. Mode of action based risk assessment of the botanical food-borne alkenylbenzene apiol from parsley using physiologically based kinetic (PBK) modelling and read-across from safrole.

    Science.gov (United States)

    Alajlouni, Abdalmajeed M; Al Malahmeh, Amer J; Kiwamoto, Reiko; Wesseling, Sebastiaan; Soffers, Ans E M F; Al-Subeihi, Ala A A; Vervoort, Jacques; Rietjens, Ivonne M C M

    2016-03-01

    The present study developed physiologically-based kinetic (PBK) models for the alkenylbenzene apiol in order to facilitate risk assessment based on read-across from the related alkenylbenzene safrole. Model predictions indicate that in rat liver the formation of the 1'-sulfoxy metabolite is about 3 times lower for apiol than for safrole. These data support that the lower confidence limit of the benchmark dose resulting in a 10% extra cancer incidence (BMDL10) that would be obtained in a rodent carcinogenicity study with apiol may be 3-fold higher for apiol than for safrole. These results enable a preliminary risk assessment for apiol, for which tumor data are not available, using a BMDL10 value of 3 times the BMDL10 for safrole. Based on an estimated BMDL10 for apiol of 5.7-15.3 mg/kg body wt per day and an estimated daily intake of 4 × 10(-5) mg/kg body wt per day, the margin of exposure (MOE) would amount to 140,000-385,000. This indicates a low priority for risk management. The present study shows how PBK modelling can contribute to the development of alternatives for animal testing, facilitating read-across from compounds for which in vivo toxicity studies on tumor formation are available to compounds for which these data are unavailable. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Balloon cell nevus of the iris.

    Science.gov (United States)

    Morcos, Mohib W; Odashiro, Alexandre; Bazin, Richard; Pereira, Patricia Rusa; O'Meara, Aisling; Burnier, Miguel N

    2014-12-01

    Balloon cell nevus is a rare histopathological lesion characterized by a predominance of large, vesicular and clear cells, called balloon cells. There is only 1 case of balloon cell nevus of the iris reported in the literature. A 55 year-old man presented a pigmented elevated lesion in the right iris since the age of 12 years old. The lesion had been growing for the past 2 years and excision was performed. Histopathological examination showed a balloon cell nevus composed of clear and vacuolated cells without atypia. A typical spindle cell nevus of the iris was also observed. The differential diagnosis included xanthomatous lesions, brown adipocyte or other adipocytic lesions, clear cell hidradenoma, metastatic clear cell carcinoma of the kidney and clear cell sarcoma. The tumor was positive for Melan A, S100 protein and HMB45. Balloon cell nevus of the iris is rare but should be considered in the differential diagnosis of melanocytic lesions of the iris. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Computer Programs for Calculating and Plotting the Stability Characteristics of a Balloon Tethered in a Wind

    Science.gov (United States)

    Bennett, R. M.; Bland, S. R.; Redd, L. T.

    1973-01-01

    Computer programs for calculating the stability characteristics of a balloon tethered in a steady wind are presented. Equilibrium conditions, characteristic roots, and modal ratios are calculated for a range of discrete values of velocity for a fixed tether-line length. Separate programs are used: (1) to calculate longitudinal stability characteristics, (2) to calculate lateral stability characteristics, (3) to plot the characteristic roots versus velocity, (4) to plot the characteristic roots in root-locus form, (5) to plot the longitudinal modes of motion, and (6) to plot the lateral modes for motion. The basic equations, program listings, and the input and output data for sample cases are presented, with a brief discussion of the overall operation and limitations. The programs are based on a linearized, stability-derivative type of analysis, including balloon aerodynamics, apparent mass, buoyancy effects, and static forces which result from the tether line.

  19. Scientific ballooning. Proceedings of the symposium on the scientific use of balloons and related technical problems, Innsbruck, Austria, May 29-June 10, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Riedler, W

    1979-01-01

    The book includes works on operational and technical aspects of balloon launching I and II, cooperative balloon campaigns, and new developments in scientific use of balloons. The specific topics discussed are coordinated balloon and rocket measurements of stratospheric wind shears and turbulence, ballooning in Japan and India, magnetospheric processes investigated with data taken from balloon flights, and remote sensing of middle atmosphere winds from balloon platforms.

  20. Balloon dilatation of the prostatic urethra

    International Nuclear Information System (INIS)

    Lee, Yeon Soo; Shim, Hyung Jin; Cha, Kyung Soo; Hong, Ju Hee; Lim, Myung Ah; Kim, Cheol Soo

    1991-01-01

    We analyzed the result of transurethral balloon dilatation in 11 patients with benign prostatic hypertrophy. The procedures were performed under intravenous sedation and local anesthesia with double lumen balloon catheter at 4 atmosphere for 10 minutes. After dilatation, the prostatism symptom scores improved in 10 out of 11 patients and the mean diameter of the prostatic urethra significantly increased form 4.3 mm to 10.2 mm (ρ < 0.005). The procedures were successful not only in lateral lobe hypertrophy but also in median lobe hypertrophy of the prostate. Postdilatation MRI of 1 patient showed an intact prostatic capsule and no periprostatic hematoma. Complications did not develop except in 1 patient with mild hematuria and incontinence. These preliminary results suggest that transurethral balloon dilatation can be an effective and safe treatment modality for benign prostatic hypertrophy

  1. Innovations in Balloon Catheter Technology in Rhinology.

    Science.gov (United States)

    D'Anza, Brian; Sindwani, Raj; Woodard, Troy D

    2017-06-01

    Since being introduced more than 10 years ago, balloon catheter technology (BCT) has undergone several generations of innovations. From construction to utilization, there has been a myriad of advancements in balloon technology. The ergonomics of the balloon dilation systems have improved with a focus on limiting the extra assembly. "Hybrid" BCT procedures have shown promise in mucosal preservation, including treating isolated complex frontal disease. Multiple randomized clinical trials report improved long-term outcomes in stand-alone BCT, including in-office use. The ever-expanding technological innovations ensure BCT will be a key component in the armamentarium of the modern sinus surgeon. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Wind-Driven Montgolfiere Balloons for Mars

    Science.gov (United States)

    Jones, Jack A.; Fairbrother, Debora; Lemieux, Aimee; Lachenmeier, Tim; Zubrin, Robert

    2005-01-01

    Solar Montgolfiere balloons, or solar-heated hot air balloons have been evaluated by use on Mars for about 5 years. In the past, JPL has developed thermal models that have been confirmed, as well as developed altitude control systems to allow the balloons to float over the landscape or carry ground sampling instrumentation. Pioneer Astronautics has developed and tested a landing system for Montgolfieres. JPL, together with GSSL. have successfully deployed small Montgolfieres (<15-m diameter) in the earth's stratosphere, where conditions are similar to a Mars deployment. Two larger Montgolfieres failed, however, and a series of larger scale Montgolfieres is now planned using stronger, more uniform polyethylene bilaminate, combined with stress-reducing ripstitch and reduced parachute deceleration velocities. This program, which is presently under way, is a joint effort between JPL, WFF, and GSSL, and is planned for completion in three years.

  3. Robotic weather balloon launchers spread in Alaska

    Science.gov (United States)

    Rosen, Julia

    2018-04-01

    Last week, things began stirring inside the truck-size box that sat among melting piles of snow at the airport in Fairbanks, Alaska. Before long, the roof of the box yawned open and a weather balloon took off into the sunny afternoon, instruments dangling. The entire launch was triggered with the touch of a button, 5 kilometers away at an office of the National Weather Service (NWS). The flight was smooth, just one of hundreds of twice-daily balloon launches around the world that radio back crucial data for weather forecasts. But most of those balloons are launched by people; the robotic launchers, which are rolling out across Alaska, are proving to be controversial. NWS says the autolaunchers will save money and free up staff to work on more pressing matters. But representatives of the employee union question their reliability, and say they will hasten the end of Alaska's remote weather offices, where forecasting duties and hours have already been slashed.

  4. Advanced Onboard Energy Storage Solution for Balloons, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Balloon Programs at NASA are looking for a potential 100 day missions at mid-altitudes. These balloons would be powered by solar panels to take advantage of...

  5. Long distance cell communication using spherical tether balloons

    Science.gov (United States)

    Manchanda, R. K.; Rajagopalan, Vasudevan; Vasudevan, Rajagopalan; Mehrotra, R. K.; Sreenivasan, S.; Pawaskar, M.; Subba Rao Jonnalagadda, Venkata; Buduru, Suneelkumar; Kulkarni, P. M.

    A proof-of-concept experiment was conducted for long-range cell communication for rural tele-phony and internet. We designed and fabricated a spherical tether balloon to carry the con-ventional micro base transceiver station (BTS) along with three slotted antenna to cover 2-pi radius. AC power and optical fiber were anchored along with the tether line. A special fre-quency license was obtained from Wireless Planning Commission (WPC) wing of Department of Telecommunication (DoT), India for the period of experiment so as not to affect the opera-tional networks. The experiments were carried out for different BTS heights up to 500 meter. Signal measurement both in data mode and voice quality were done in different quadrant using mobile vans. This paper describes the methodology (under patenting) and utility of technique for operational application.

  6. False coronary dissection with the new Monorail angioplasty balloon catheter.

    Science.gov (United States)

    Esplugas, E; Cequier, A R; Sabaté, X; Jara, F

    1990-01-01

    During percutaneous transluminal coronary angioplasty, the appearance of persistent staining in the vessel by contrast media suggests coronary dissection. We report seven patients in whom a false image of severe coronary dissection was observed during angioplasty performed with the new Monorail balloon catheter. This image emerges at the moment of balloon inflation, is distally located to the balloon, and disappears with balloon catheter deflation. No complications were associated with the appearance of this image.

  7. Particle Astrophysics in NASA's Long Duration Balloon Program

    International Nuclear Information System (INIS)

    Gorham, Peter W.

    2013-01-01

    A century after Viktor Hess' discovery of cosmic rays, balloon flights still play a central role in the investigation of cosmic rays over nearly their entire spectrum. We report on the current status of NASA balloon program for particle astrophysics, with particular emphasis on the very successful Antarctic long-duration balloon program, and new developments in the progress toward ultra-long duration balloons

  8. Balloon catheter dilatation of esophageal strictures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeung Sook; Yoon, Yup; Sung, Dong Yook; Choi, Woo Suk; Nam, Kyung Jin; Lim, Jae Hoon [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    1990-07-15

    The authors performed 27 fluoroscopically guided balloon dilatation in 12 patients of esophageal stricture during recent 3 years. The causes of esophageal stricture were corrosive esophagitis (N=2) and congenital narrowing (N=1), including postoperative narrowing in achalasia (N=3), esophageal varix (N=3), lye stricture (N=2) and esophageal cancer (N=1). Successful dilatation of the stricture was achieved during the procedure in 10 patients(83%). Major complication such as esophageal rupture was not found. The authors conclude that fluoroscopically guided esophageal balloon dilatation is a safe and effective method for treatment of symptomatic esophageal strictures.

  9. Balloon catheter dilatation of esophageal strictures

    International Nuclear Information System (INIS)

    Kim, Jeung Sook; Yoon, Yup; Sung, Dong Yook; Choi, Woo Suk; Nam, Kyung Jin; Lim, Jae Hoon

    1990-01-01

    The authors performed 27 fluoroscopically guided balloon dilatation in 12 patients of esophageal stricture during recent 3 years. The causes of esophageal stricture were corrosive esophagitis (N=2) and congenital narrowing (N=1), including postoperative narrowing in achalasia (N=3), esophageal varix (N=3), lye stricture (N=2) and esophageal cancer (N=1). Successful dilatation of the stricture was achieved during the procedure in 10 patients(83%). Major complication such as esophageal rupture was not found. The authors conclude that fluoroscopically guided esophageal balloon dilatation is a safe and effective method for treatment of symptomatic esophageal strictures

  10. Performance of the EUSO-Balloon electronics

    International Nuclear Information System (INIS)

    Barrillon, P.; Dagoret, S.; Miyamoto, H.; Moretto, C.; Bacholle, S.; Blaksley, C; Gorodetzky, P.; Jung, A.; Prévôt, G.; Prat, P.; Bayer, J.; Blin, S.; Taille, C. De La; Cafagna, F.; Fornaro, C.; Karczmarczyk, J.; Tanco, G. Medina; Osteria, G.; Perfetto, F.; Park, I.

    2016-01-01

    The 24th of August 2014, the EUSO-Balloon instrument went for a night flight for several hours, 40 km above Timmins (Canada) balloon launching site, concretizing the hard work of an important part of the JEM-EUSO collaboration started 3 years before. This instrument consists of a telescope made of two lenses and a complex electronic chain divided in two main sub-systems: the PDM (Photo Detector Module) and the DP (Data Processor). Each of them is made of several innovative elements developed and tested in a short time. This paper presents their performances before and during the flight

  11. Clinical experience with the Monorail balloon catheter for coronary angioplasty.

    Science.gov (United States)

    Finci, L; Meier, B; Roy, P; Steffenino, G; Rutishauser, W

    1988-01-01

    The Monorail balloon catheter is distinctly different from other current balloon catheters: the guidewire passes through the balloon itself, exits the catheter proximal to the balloon, and runs alongside its small shaft (3 French) through the guiding catheter. Monorail coronary angioplasty was attempted in 61 patients on 73 lesions with balloons from 2.0 to 3.7 mm. Angiographic success was obtained in 66 lesions (90%). For 15 lesions, balloon exchanges were needed. In three lesions, the Monorail balloon failed to cross the lesion, while a standard balloon succeeded; two lesions could not be crossed with any balloon. Vessel occlusion occurred in four patients: two had emergency surgery without infarct (one died suddenly 4 days later and one had a stroke 1 day later), one was recanalized with a standard balloon, and one had a myocardial infarct. Continuous infusion of urokinase was used until patient 3 in whom problems with the delivery system led to cardiocerebral air embolization (with complete recovery). No thrombotic complications were observed in the subsequent 58 patients with only a bolus of 10,000 U of heparin. The Monorail balloon facilitates contrast injections and balloon exchanges but appears more difficult to pass through tight lesions. Omission of the previously recommended infusion with a thrombolytic agent proved safe.

  12. 21 CFR 884.5050 - Metreurynter-balloon abortion system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Metreurynter-balloon abortion system. 884.5050... Devices § 884.5050 Metreurynter-balloon abortion system. (a) Identification. A metreurynter-balloon abortion system is a device used to induce abortion. The device is inserted into the uterine cavity...

  13. How to perform combined cutting balloon and high pressure balloon valvuloplasty for dogs with subaortic stenosis.

    Science.gov (United States)

    Kleman, Mandi E; Estrada, Amara H; Maisenbacher, Herbert W; Prošek, Robert; Pogue, Brandon; Shih, Andre; Paolillo, Joseph A

    2012-01-01

    Subvalvular aortic stenosis (SAS) is one of the most common congenital cardiac malformations in dogs. Unfortunately, the long term success rate and survival data following either open heart surgery or catheter based intervention has been disappointing in dogs with severe subaortic stenosis. Medical therapy is currently the only standard recommended treatment option. A cutting balloon dilation catheter has been used successfully for resistant coronary artery and peripheral pulmonary arterial stenoses in humans. This catheter is unique in that it has the ability to cut, or score, the stenotic region prior to balloon dilatation of the stenosis. The use of cutting balloon valvuloplasty combined with high pressure valvuloplasty for dogs with severe subaortic stenosis has recently been reported to be a safe and feasible alternative therapeutic option. The following report describes this technique, outlines the materials required, and provides some 'tips' for successful percutaneous subaortic balloon valvuloplasty. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Percutaneous balloon dilation of pulmonary stenosis

    International Nuclear Information System (INIS)

    Hua Yangde; Huang Ming; Li Jinkang; Qian Jinqing; Chen Xiuyu; Yang Siyuan

    2003-01-01

    Objective: Review our experience of balloon dilation of valvular pulmonary stenosis in 32 cases. Methods: Totally 32 cases of pulmonary stenosis admitted from 1995-2001 with age of 1.5-13 yrs mean 6.8. Diagnosis was made by clinical manifestations, EKG, ECHO and angiocardiography. Results: Before dilation, the mean systolic pressure of right ventricle was (93.5 ± 28.5) mmHg, after the procedure it reduced to (42 ± 9.0) mmHg. The pressure gradient between right ventricle and pulmonary artery before dilation was (76 ± 30) mmHg and become (24.5 ± 8.5) mmHg after dilation. The gradient pressure after dilation was less than 25 mmHg in 90.6% cases. A case of Noonan syndrome showed no response to balloon dilation and died during valvulectomy from accompanying left ventricular cardiomyopathy. Conclusions: Balloon dilation of valvular pulmonary stenosis is effective and safe. The selection of proper diameter of pulmonary valvular rings and sized of the balloon are the major factors

  15. There is a Text in 'The Balloon'

    DEFF Research Database (Denmark)

    Elias, Camelia

    2009-01-01

    From the Introduction: Camelia Elias' "There is a Text in 'The Balloon': Donald Barthelme's Allegorical Flights" provides its reader with a much-need and useful distinction between fantasy and the fantastic: "whereas fantasy in critical discourse can be aligned with allegory, in which a supernatu...

  16. Teacher's Guide for Balloons and Gases.

    Science.gov (United States)

    Griffith, Joe H.; And Others

    This guide was developed to provide children with an opportunity to prepare and collect several common gases and to discover and work with some of their properties. The guide is divided into five major sections: (1) introduction, (2) materials, (3) activities, (4) balloons aloft, and (5) an appendix. The introduction provides information…

  17. Teaching Earth Science Using Hot Air Balloons

    Science.gov (United States)

    Kuhl, James; Shaffer, Karen

    2008-01-01

    Constructing model hot air balloons is an activity that captures the imaginations of students, enabling teachers to present required content to minds that are open to receive it. Additionally, there are few activities that lend themselves to integrating so much content across subject areas. In this article, the authors describe how they have…

  18. Balloon-borne radiometer profiler: Field observations

    International Nuclear Information System (INIS)

    Shaw, W.J.; Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Hubbe, J.M.; Scott, K.A.

    1995-03-01

    This project involves the development of the capability of making routine soundings of broadband radiative fluxes and radiative flux divergences to heights of 1500m AGL. Described in this document are radiometers carried on a stabilized platform in a harness inserted in the tetherline of a tethered balloon meteriological sounding system. Field test results are given

  19. Modified jailed balloon technique for bifurcation lesions.

    Science.gov (United States)

    Saito, Shigeru; Shishido, Koki; Moriyama, Noriaki; Ochiai, Tomoki; Mizuno, Shingo; Yamanaka, Futoshi; Sugitatsu, Kazuya; Tobita, Kazuki; Matsumi, Junya; Tanaka, Yutaka; Murakami, Masato

    2017-12-04

    We propose a new systematic approach in bifurcation lesions, modified jailed balloon technique (M-JBT), and report the first clinical experience. Side branch occlusion brings with a serious complication and occurs in more than 7.0% of cases during bifurcation stenting. A jailed balloon (JB) is introduced into the side branch (SB), while a stent is placed in the main branch (MB) as crossing SB. The size of the JB is half of the MB stent size. While the proximal end of JB attaching to MB stent, both stent and JB are simultaneously inflated with same pressure. JB is removed and then guidewires are recrossed. Kissing balloon dilatation (KBD) and/or T and protrusion (TAP) stenting are applied as needed. Between February 2015 and February 2016, 233 patients (254 bifurcation lesions including 54 left main trunk disease) underwent percutaneous coronary intervention (PCI) using this technique. Procedure success was achieved in all cases. KBD was performed for 183 lesions and TAP stenting was employed for 31 lesions. Occlusion of SV was not observed in any of the patients. Bench test confirmed less deformity of MB stent in M-JBT compared with conventional-JBT. This is the first report for clinical experiences by using modified jailed balloon technique. This novel M-JBT is safe and effective in the preservation of SB patency during bifurcation stenting. © 2017 Wiley Periodicals, Inc.

  20. The French balloon and sounding rocket space program

    Science.gov (United States)

    Coutin/Faye, S.; Sadourny, I.

    1987-08-01

    Stratospheric and long duration flight balloon programs are outlined. Open stratospheric balloons up to 1 million cu m volume are used to carry astronomy, solar system, aeronomy, stratosphere, biology, space physics, and geophysics experiments. The long duration balloons can carry 50 kg payloads at 20 to 30 km altitude for 10 days to several weeks. Pressurized stratospheric balloons, and infrared hot air balloons are used. They are used to study the dynamics of stratospheric waves and atmospheric water vapor. Laboratories participating in sounding rocket programs are listed.

  1. Kinetic Typography

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Djonov, Emilia

    2014-01-01

    After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images.......After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....

  2. NASA balloon design and flight - Philosophy and criteria

    Science.gov (United States)

    Smith, I. S., Jr.

    1993-01-01

    The NASA philosophy and criteria for the design and flight of scientific balloons are set forth and discussed. The thickness of balloon films is standardized at 20.3 microns to isolate potential film problems, and design equations are given for specific balloon parameters. Expressions are given for: flight-stress index, total required thickness, cap length, load-tape rating, and venting-duct area. The balloon design criteria were used in the design of scientific balloons under NASA auspices since 1986, and the resulting designs are shown to be 95 percent effective. These results represent a significant increase in the effectiveness of the balloons and therefore indicate that the design criteria are valuable. The criteria are applicable to four balloon volume classes in combination with seven payload ranges.

  3. Overview of the NASA balloon R&D program

    Science.gov (United States)

    Smith, I. Steve, Jr.

    1994-01-01

    The catastrophic balloon failure during the first half of the 1980's identified the need for a comprehensive and continuing balloon research and development (R&D) commitment by NASA. Technical understanding was lacking in many of the disciplines and processes associated with scientific ballooning. A comprehensive balloon R&D plan was developed in 1986 and implemented in 1987. The objectives were to develop the understanding of balloon system performance, limitations, and failure mechanisms. The program consisted of five major technical areas: structures, performance and analysis, materials, chemistry and processing, and quality control. Research activitites have been conducted at NASA/Goddard Space Flight Center (GSFC)-Wallops Flight Facility (WFF), other NASA centers and government facilities, universities, and the balloon manufacturers. Several new and increased capabilities and resources have resulted from this activity. The findings, capabilities, and plan of the balloon R&D program are presented.

  4. Tearing mode instability due to anomalous resistivity

    International Nuclear Information System (INIS)

    Furuya, Atsushi; Itoh, Sanae I.; Yagi, Masatoshi

    2000-01-01

    Tearing mode instability in the presence of microscopic truculence is investigates. The effects of microscopic turbulence on tearing mode are taken as drags which are calculated by one-point renormalization method and mean-field approximation. These effects are reduced to effective diffusivities in reduced MHD equations. Using these equations, the stability analyses of the tearing mode are performed. It is shown that a finite amplitude of fluctuation enhances the growth rate of tearing mode. For very high values of turbulent diffusivities, marginally stable state exists. The effects of each turbulent diffusivity on mode stability are examined near marginal stability boundary. Parameter dependence of the resistive ballooning mode turbulence on tearing mode is analyzed as an example. (author)

  5. PROGRESS IN THE PEELING-BALLOONING MODEL OF ELMS: TOROIDAL ROTATION AND 3D NONLINEAR DYNAMICS

    International Nuclear Information System (INIS)

    SNYDER, P.B.; WILSON, H.R.; XU, X.Q.; WEBSTER, A.J.

    2004-01-01

    Understanding the physics of the H-Mode pedestal and edge localized modes (ELMs) is very important to next-step fusion devices for two primary reasons: (1) The pressure at the top of the edge barrier (''pedestal height'') strongly impacts global confinement and fusion performance, and (2) large ELMs lead to localized transient heat loads on material surfaces that may constrain component lifetimes. The development of the peeling-ballooning model has shed light on these issues by positing a mechanism for ELM onset and constraints on the pedestal height. The mechanism involves instability of ideal coupled ''peeling-ballooning'' modes driven by the sharp pressure gradient and consequent large bootstrap current in the H-mode edge. It was first investigated in the local, high-n limit [1], and later quantified for non-local, finite-n modes in general toroidal geometry [2,3]. Important aspects are that a range of wavelengths may potentially be unstable, with intermediate n's (n ∼ 3-30) generally limiting in high performance regimes, and that stability bounds are strongly sensitive to shape [Fig l(a)], and to collisionality (i.e. temperature and density) [4] through the bootstrap current. The development of efficient MHD stability codes such as ELITE [3,2] and MISHKA [5] has allowed detailed quantification of peeling-ballooning stability bounds (e.g. [6]) and extensive and largely successful comparisons with observation (e.g. [2,6-9]). These previous calculations are ideal, static, and linear. Here we extend this work to incorporate the impact of sheared toroidal rotation, and the non-ideal, nonlinear dynamics which must be studied to quantify ELM size and heat deposition on material surfaces

  6. In vitro analysis of balloon cuffing phenomenon: inherent biophysical properties of catheter material or mechanics of catheter balloon deflation?

    Science.gov (United States)

    Chung, Eric; So, Karina

    2012-06-01

    To investigates the different methods of balloon deflation, types of urinary catheters and exposure to urine media in catheter balloon cuffing. Bardex®, Bard-Lubri-Sil®, Argyle®, Releen® and Biocath® were tested in sterile and E.Coli inoculated urine at 0, 14 and 28 days. Catheter deflation was performed with active deflation; passive deflation; passive auto-deflation; and excision of the balloon inflow channel. Balloon cuffing was assessed objectively by running the deflated balloon over a plate of agar and subjectively by 3 independent observers. Bardex®, Argyle® and Biocath® showed greater degree of catheter balloon cuffing (p deflation was the worst method (p 0.05). Linear regression model analysis confirmed time as the most significant factor. The duration of catheters exposure, different deflation methods and types of catheters tested contributed significantly to catheter balloon cuffing (p < 0.01).

  7. Nonlinear simulation of edge-localized mode in spherical tokamak

    International Nuclear Information System (INIS)

    Mizuguchi, N.; Hayashi, T.; Nakajima, N.; Khan, R.

    2006-10-01

    A numerical modeling for the dynamics of an edge-localized mode (ELM) crash in the spherical tokamak is proposed with a consecutive scenario which is initiated by the spontaneous growth of the ballooning mode instability by means of a three-dimensional nonlinear magnetohydrodynamic simulation. The simulation result shows a two-step relaxation process which is induced by the intermediate-n ballooning instability followed by the m/n=1/1 internal kink mode, where m and n represent the poloidal and toroidal mode numbers, respectively. By comparing with the experimental observations, we have found that the simulation result can reproduce several characteristic features of the so-called type-I ELM in an appropriate time scale: (1) relation to the ballooning instability, (2) intermediate-n precursors, (3) low-n structure on the crash, (4) formation and separation of the filament, and (5) considerable amount of loss of plasma. Furthermore, the model is verified by examining the effect of diamagnetic stabilization and comparing the nonlinear behavior with that of the peeling modes. The ion diamagnetic drift terms are found to stabilize some specific components linearly; nevertheless they are not so effective in the nonlinear dynamics such as the filament formation and the amount of loss. For the peeling mode case, no prominent filament structure is formed in contrast to the ballooning case. (author)

  8. Ballooning for Biologists: Mission Essentials for Flying Experiments on Large NASA Balloons

    Science.gov (United States)

    Smith, David J.; Sowa, Marianne

    2017-01-01

    Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically-relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earths stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day after flying. The National Aeronautics and Space Administration (NASA) flies large, unmanned scientific balloons from all over the globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (approx. 35 km above sea level) will be exposed to an environment similar to the surface of Mars: temperatures generally around -36 C, atmospheric pressure at a thin 1 kPa, relative humidity levels <1%, and a harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/sq m and 0.1 mGy/d, respectively) that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering the operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (ground, low Earth orbit, and deep space studies). Our presentation targets biologists with no background or experience in scientific ballooning. We will provide an overview of large balloon operations, biology topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.

  9. Excitation of macromagnetohydrodynamic mode due to multiscale interaction in a quasi-steady equilibrium formed by a balance between microturbulence and zonal flow

    International Nuclear Information System (INIS)

    Ishizawa, A.; Nakajima, N.

    2007-01-01

    This is the first numerical simulation demonstrating that a macromagnetohydrodynamic (macro-MHD) mode is excited as a result of multi-scale interaction in a quasi-steady equilibrium formed by a balance between microturbulence and zonal flow based on a reduced two-fluid model. This simulation of a macro-MHD mode, a double tearing mode, is accomplished in a reversed shear equilibrium that includes zonal flow and turbulence due to kinetic ballooning modes. In the quasi-steady equilibrium, a macroscale fluctuation that has the same helicity as the double tearing mode is a part of the turbulence. After a certain period of time, the macro-MHD mode begins to grow. It effectively utilizes free energy of the equilibrium current density gradient and is destabilized by a positive feedback loop between zonal flow suppression and magnetic island growth. Thus, once the macro-MHD appears from the quasi-equilibrium, it continues to grow steadily. This simulation is more comparable with experimental observations of growing macro-MHD activity than earlier MHD simulations starting from linear macroinstabilities in a static equilibrium

  10. Retrograde prostatic urethroplasty with balloon catheter

    International Nuclear Information System (INIS)

    Castaneda, F.; Reddy, P.; Hulbert, J.; Letourneau, J.G.; Hunter, D.W.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1987-01-01

    The authors performed retrograde prostatic urethroplasty in 18 patients using a 25-mm urethroplasty balloon catheter. The procedure was performed on an outpatient basis under local anesthesia. Voiding cystourethrography, retrograde urethrography, rectal US, and MRE imaging were performed before and immediately after the procedure and at 2 weeks and 3, 6, 12, and 18 months. Long-term results at 18 months and possible clinical implications are discussed

  11. Long Duration Balloon Charge Controller Stack Integration

    Science.gov (United States)

    Clifford, Kyle

    NASA and the Columbia Scientific Balloon Facility are interested in updating the design of the charge controller on their long duration balloon (LDB) in order to enable the charge controllers to be directly interfaced via RS232 serial communication by a ground testing computers and the balloon's flight computer without the need to have an external electronics stack. The design involves creating a board that will interface with the existing boards in the charge controller in order to receive telemetry from and send commands to those boards, and interface with a computer through serial communication. The inputs to the board are digital status inputs indicating things like whether the photovoltaic panels are connected or disconnected; and analog inputs with information such as the battery voltage and temperature. The outputs of the board are 100ms duration command pulses that will switch relays that do things like connect the photovoltaic panels. The main component of this design is a PIC microcontroller which translates the outputs of the existing charge controller into serial data when interrogated by a ground testing or flight computer. Other components involved in the design are an AD7888 12-bit analog to digital converter, a MAX3232 serial transceiver, various other ICs, capacitors, resistors, and connectors.

  12. Numerical Modelling Of Pumpkin Balloon Instability

    Science.gov (United States)

    Wakefield, D.

    Tensys have been involved in the numerical formfinding and load analysis of architectural stressed membrane structures for 15 years. They have recently broadened this range of activities into the `lighter than air' field with significant involvement in aerostat and heavy-lift hybrid airship design. Since early 2004 they have been investigating pumpkin balloon instability on behalf of the NASA ULDB programme. These studies are undertaken using inTENS, an in-house finite element program suite based upon the Dynamic Relaxation solution method and developed especially for the non-linear analysis and patterning of membrane structures. The paper describes the current state of an investigation that started with a numerical simulation of the lobed cylinder problem first studied by Calladine. The influence of material properties and local geometric deformation on stability is demonstrated. A number of models of complete pumpkin balloons have then been established, including a 64-gore balloon with geometry based upon Julian Nott's Endeavour. This latter clefted dramatically upon initial inflation, a phenomenon that has been reproduced in the numerical model. Ongoing investigations include the introduction of membrane contact modelling into inTENS and correlation studies with the series of large-scale ULDB models currently in preparation.

  13. Beta limits in H-modes and VH-modes in JET

    Energy Technology Data Exchange (ETDEWEB)

    Smeulders, P; Hender, T C; Huysmans, G; Marcus, F; Ali-Arshad, S; Alper, B; Balet, B; Bures, M; Deliyanakis, N; Esch, H de; Fshpool, G; Jarvis, O N; Jones, T T.C.; Ketner, W; Koenig, R; Lawson, K; Lomas, P; O` Brien, D; Sadler, G; Stok, D; Stubberfield, P; Thomas, P; Thomen, K; Wesson, J [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Nave, M F [Universidade Tecnica, Lisbon (Portugal). Inst. Superior Tecnico

    1994-07-01

    In Hot-ion H- and VH-modes, the highest achieved beta was about 10% below the Troyon value in the best case of discharge 26087. The operational space of the high beta discharges obtained before March 1992 has been explored as function of the parameters H{sub ITER89P}, {beta}{sub n}, q{sub 95}, I{sub p}. Also, a limiting envelope on the fusion reactivity as a function of the average plasma pressure and beta has been observed with R{sub DD} related to {beta}{sub {phi}}{sup 2}.B{sub {phi}}{sup 4}. MHD stability analysis shows that the JET VH modes at the edge are in the second region for ballooning mode stability. The dependence of ballooning stability and the n=1 external kink on the edge current density is analyzed. (authors). 6 figs., 6 refs.

  14. Recent activities on the scientific ballooning in Japan

    International Nuclear Information System (INIS)

    Nisimura, J.; Hirosawa, H.

    1984-01-01

    Scientific ballooning is Japan has been organized by the Institute of Space and Astronautical Science, and about 15 balloons have been launched each year from Sanriku Balloon Center that belongs to this Institute. The balloon center is located in the northern part of Japan. The observations cover the field of X-ray, gamma-ray, infrared astronomy, cosmic rays, and atmospheric science. Systems of lon duration flights such as 'Boomerang Balloons', and fine attitude control systems were developed and widely applied to the scientific observations. International collaborative works were performed in Australia and Indonesia last year. Some details of these activities are reported and possible future collaborations with Braziian balloon group are also discussed. (Author) [pt

  15. Percutaneous treatment of extrahepatic bile duct stones assisted by balloon sphincteroplasty and occlusion balloon

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Sung; Kim, Ji Hyung; Choi, Young Woo; Lee, Tae Hee; Hwang, Cheol Mog; Cho, Young Jun; Kim, Keum Won [Konyang University Hospital, Daejeon (Korea, Republic of)

    2005-12-15

    To describe the technical feasibility and usefulness of extrahepatic biliary stone removal by balloon sphincteroplasty and occlusion balloon pushing. Fifteen patients with extrahepatic bile duct stones were included in this study. Endoscopic stone removal was not successful in 13 patients, and two patients refused the procedure due to endoscopy phobia. At first, all patients underwent percutaneous transhepatic biliary drainage (PTBD). A few days later, through the PTBD route, balloon assisted dilatation for common bile duct (CBD) sphincter was performed, and then the stones were pushed into the duodenum using an 11.5 mm occlusion balloon. Success rate, reason for failure, and complications associated with the procedure were evaluated. Eight patients had one stone, five patients had two stones, and two patients had more than five stones. The procedure was successful in 13 patients (13/15). In 12 of the patients, all stones were removed in the first trial. In one patients, residual stones were discovered on follow-up cholangiography, and were subsequently removed in the second trial. Technical failure occurred in two patients. Both of these patients had severely dilated CBD and multiple stones with various sizes. Ten patients complained of pain in the right upper quadrant and epigastrium of the abdomen immediately following the procedure, but there were no significant procedure-related complications such as bleeding or pancreatitis. Percutaneous extrahepatic biliary stone removal by balloon sphincteroplasty and subsequent stone pushing with occlusion balloon is an effective, safe, and technically feasible procedure which can be used as an alternative method in patients when endoscopic extrahepatic biliary stone removal was not successful.

  16. Percutaneous treatment of extrahepatic bile duct stones assisted by balloon sphincteroplasty and occlusion balloon

    International Nuclear Information System (INIS)

    Park, Yong Sung; Kim, Ji Hyung; Choi, Young Woo; Lee, Tae Hee; Hwang, Cheol Mog; Cho, Young Jun; Kim, Keum Won

    2005-01-01

    To describe the technical feasibility and usefulness of extrahepatic biliary stone removal by balloon sphincteroplasty and occlusion balloon pushing. Fifteen patients with extrahepatic bile duct stones were included in this study. Endoscopic stone removal was not successful in 13 patients, and two patients refused the procedure due to endoscopy phobia. At first, all patients underwent percutaneous transhepatic biliary drainage (PTBD). A few days later, through the PTBD route, balloon assisted dilatation for common bile duct (CBD) sphincter was performed, and then the stones were pushed into the duodenum using an 11.5 mm occlusion balloon. Success rate, reason for failure, and complications associated with the procedure were evaluated. Eight patients had one stone, five patients had two stones, and two patients had more than five stones. The procedure was successful in 13 patients (13/15). In 12 of the patients, all stones were removed in the first trial. In one patients, residual stones were discovered on follow-up cholangiography, and were subsequently removed in the second trial. Technical failure occurred in two patients. Both of these patients had severely dilated CBD and multiple stones with various sizes. Ten patients complained of pain in the right upper quadrant and epigastrium of the abdomen immediately following the procedure, but there were no significant procedure-related complications such as bleeding or pancreatitis. Percutaneous extrahepatic biliary stone removal by balloon sphincteroplasty and subsequent stone pushing with occlusion balloon is an effective, safe, and technically feasible procedure which can be used as an alternative method in patients when endoscopic extrahepatic biliary stone removal was not successful

  17. Hot air balloons fill gap in atmospheric and sensing platforms

    Science.gov (United States)

    Watson, Steven M.; Price, Russ

    Eric Edgerton was having a problem he could not solve: how to noninvasively collect in situ incinerator plume data. So he called in the Air Force and learned about its Atmospheric and Sensor Test Platform program; its platform is a manned hot air balloon. Many investigators are discovering the advantages of hot air balloons as stable, inexpensive platforms for performing in situ atmospheric measurements. Some are also using remote sensing capabilities on the balloon platforms.

  18. Location and data collection for long stratospheric balloon flights

    Science.gov (United States)

    Malaterre, P.

    Stratospheric balloons capable of taking a 30 kg scientific payload to an altitude of 22 to 30 km for 1 month or more were developed. In-flight experiments were used to qualify the designs of a pumpkin shaped superpressure balloon and an infrared hot air balloon. Tracking of the flights (location and transmission of the parameters measured on board) was achieved using a telemetry gondola including an ARGOS beacon adapted for operation in the low temperatures encountered.

  19. The role of scientific ballooning for exploration of the magnetosphere

    International Nuclear Information System (INIS)

    Block, L.P.; Lazutin, L.L.; Riedler, W.

    1984-11-01

    The magnetosphere is explored in situ by satellites, but measurements near the low altitude magnetospheric boundary by rockets, balloons and groundbased instruments play a very significant role. The geomagnetic field provides a frame with anisotropic wave and particle propagation effects, enabling remote sensing of the distant magnetosphere by means of balloon-borne and groundbased instruments. Examples will be given of successful studies, with coordinated satellite and balloon observations, of substorm, pulsation and other phenomena propagating both along and across the geomagnetic field. Continued efforts with sophisticated balloon-borne instrumentations should contribute substantially to our understanding of magnetospheric physics. (Author)

  20. Deflation of gastric band balloon in pregnancy for improving outcomes.

    Science.gov (United States)

    Jefferys, Amanda E; Siassakos, Dimitrios; Draycott, Tim; Akande, Valentine A; Fox, Robert

    2013-04-30

    In line with the rise in the prevalence of obesity, an increasing number of women of childbearing age are undergoing laparoscopic adjustable gastric banding (LAGB), resulting in an increasing number of pregnancies with a band in place. Currently, there is no consensus on optimal band management in pregnancy. Some clinicians advocate leaving the band balloon inflated to reduce gestational weight gain and associated adverse perinatal outcomes. However, there are concerns that maintaining balloon inflation during pregnancy might increase the risk of band complications and adversely affect fetal development and/or growth as a result of reduced nutritional intake. To compare maternal and perinatal outcomes for elective gastric band balloon deflation versus intention to maintain balloon inflation during pregnancy. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2012) and the Web of Science database (1940 to September 2012). Randomised-controlled trials comparing elective deflation of the gastric band balloon with intention to maintain balloon inflation in pregnant women who have undergone LAGB. Two review authors independently assessed studies for inclusion. No studies met the criteria for inclusion in the review. To date no randomised controlled trials exist that compare elective deflation of the gastric band balloon in pregnancy versus intention to maintain balloon inflation. Further research is needed to define the optimum management of the gastric band balloon in pregnancy.

  1. Hyperspectral Polarimeter for Monitoring Balloon Strain, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's latest generation of superpressure, ultra long duration balloons (ULDB) extend the flight time for stratospheric experiments to levels previously unattainable...

  2. An Overview of Current and Future Stratospheric Balloon Mission Capabilities

    Science.gov (United States)

    Smith, Michael

    The modern stratospheric balloon has been used for a variety of missions since the late 1940's. Capabilities of these vehicles to carry larger payloads, fly to higher altitudes, and fly for longer periods of time have increased dramatically over this time. In addition to these basic performance metrics, reliability statistics for balloons have reached unprecedented levels in recent years. Balloon technology developed in the United States in the last decade has the potential to open a new era in economical space science using balloons. As always, the advantage of the balloon platform is the fact that missions can be carried out at a fraction of the cost and schedule of orbital missions. A secondary advantage is the fact that instruments can be re-flown numerous times while upgrading sensor and data processing technologies from year to year. New mission capabilities now have the potential for enabling ground breaking observations using balloons as the primary platform as opposed to a stepping stone to eventual orbital observatories. The limit of very high altitude balloon missions will be explored with respect to the current state of the art of balloon materials and fabrication. The same technological enablers will also be applied to possibilities for long duration missions at mid latitudes with payloads of several tons. The balloon types and their corresponding mission profiles will be presented in a performance matrix that will be useful for potential scientific users in planning future research programs.

  3. [Balloon cell nevi of the conjunctiva (author's transl)].

    Science.gov (United States)

    Schlageter, P E; Daicker, B

    1975-06-01

    The clinical and histological features of three cases of conjunctival balloon cell nevi are described. This peculiar form of nevus is very rare in the conjunctiva. The findings are compared with the descriptions in the literature of dermal balloon cell nevi. They demonstrate, that the conjunctival and dermal tumours are of idential histological structure. The proliferations of the conjunctival epithelium often found in conjunctival nevi do not modify the balloon cell nevi. These can not be diagnosed clinically. The problems of the pathogenesis of the balloon cell nevi are discussed.

  4. ELM triggering conditions for the integrated modeling of H-mode plasmas

    International Nuclear Information System (INIS)

    Pankin, A.Y.; Schnack, D.D.; Bateman, G.; Kritz, A.H.; Brennan, D.P.; Snyder, P.B.; Voitsekhovitch, I.; Kruger, S.; Janeschitz, G.; Onjun, T.; Pacher, G.W.; Pacher, H.D.

    2005-01-01

    Recent advances in the integrated modeling of ELMy H-mode plasmas are presented. A new model for the H-mode pedestal and for the triggering of ELMs predicts the height, width, and shape of the H-mode pedestal and the frequency and width of ELMs. The model for the pedestal and ELMs is used in the ASTRA integrated transport code to follow the time evolution of tokamak discharges from L-mode through the transition from L-mode to H-mode, with the formation of the H-mode pedestal, and, subsequently, to the triggering of ELMs. Turbulence driven by the ion temperature gradient mode, resistive ballooning mode, trapped electron mode, and electron temperature gradient mode contributes to the anomalous thermal transport at the plasma edge in this model. Formation of the pedestal and the L-H transition is the direct result of E(vector) r x B(vector) flow shear suppression of anomalous transport. The periodic ELM crashes are triggered by MHD instabilities. Two mechanisms for triggering ELMs are considered: ELMs are triggered by ballooning modes if the pressure gradient exceeds the ballooning threshold or by peeling modes if the edge current density exceeds the peeling mode threshold. The BALOO, DCON, and ELITE ideal MHD stability codes are used to derive a new parametric expression for the peeling-ballooning threshold. The new dependence for the peeling-ballooning threshold is implemented in the ASTRA transport code. Results of integrated modeling of DIII-D like discharges are presented and compared with experimental observations. The results from the ideal MHD stability codes are compared with results from the resistive MHD stability code NIMROD. (author)

  5. Physical kinetics

    International Nuclear Information System (INIS)

    Lifschitz, E.M.; Pitajewski, L.P.

    1983-01-01

    The textbook covers the subject under the following headings: kinetic gas theory, diffusion approximation, collisionless plasma, collisions within the plasma, plasma in the magnetic field, theory of instabilities, dielectrics, quantum fluids, metals, diagram technique for nonequilibrium systems, superconductors, and kinetics of phase transformations

  6. Estimating heat transfer bias of kinetic measurement for polymers by differential scanning calorimetry with isothermal mode; Evaluation de l'erreur due au transfert de chaleur lors des mesures cinetiques dans les polymeres par calorimetrie differentielle a balayage en mode isotherme

    Energy Technology Data Exchange (ETDEWEB)

    Danes, Florin; Garnier, Bertrand [Laboratoire de Thermocinetique, UMR CNRS 6607, Ecole Polytechnique de l' Universite de Nantes, rue C. Pauc, BP50609, 44306 cedex 3, Nantes (France)

    2003-06-01

    The non-uniformity of temperatures in the DSC sample, and the subsequent difference between mean sample temperature and measured one (in the support of the crucible) are identified as the main source of bias for the isothermal mode determination of kinetic characteristics by differential scanning calorimetry. Chemical reactions under consideration are these with important heat effects into thermal insulators, as for example the reticulation of polymeric materials.By introducing an analytical model of heat transfer in DSC reactive samples, we have performed an estimation for the upper limit of the maximal size of samples which corresponds to a given relative error of the reaction rate, as measured by isothermal DSC calorimetry. For example, with a 5% error and flat samples, we have found admissible sample thicknesses which decrease with temperature and are between 1.9 and 3.1 mm for the sulphur vulcanization of a natural rubber and between 0.6 and 1.1 mm for the reticulation of a pre-polymerized epoxy resin. (authors)

  7. Linear calculations of edge current driven kink modes with BOUT++ code

    Energy Technology Data Exchange (ETDEWEB)

    Li, G. Q., E-mail: ligq@ipp.ac.cn; Xia, T. Y. [Institute of Plasma Physics, CAS, Hefei, Anhui 230031 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Snyder, P. B.; Turnbull, A. D. [General Atomics, San Diego, California 92186 (United States); Ma, C. H.; Xi, P. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); FSC, School of Physics, Peking University, Beijing 100871 (China)

    2014-10-15

    This work extends previous BOUT++ work to systematically study the impact of edge current density on edge localized modes, and to benchmark with the GATO and ELITE codes. Using the CORSICA code, a set of equilibria was generated with different edge current densities by keeping total current and pressure profile fixed. Based on these equilibria, the effects of the edge current density on the MHD instabilities were studied with the 3-field BOUT++ code. For the linear calculations, with increasing edge current density, the dominant modes are changed from intermediate-n and high-n ballooning modes to low-n kink modes, and the linear growth rate becomes smaller. The edge current provides stabilizing effects on ballooning modes due to the increase of local shear at the outer mid-plane with the edge current. For edge kink modes, however, the edge current does not always provide a destabilizing effect; with increasing edge current, the linear growth rate first increases, and then decreases. In benchmark calculations for BOUT++ against the linear results with the GATO and ELITE codes, the vacuum model has important effects on the edge kink mode calculations. By setting a realistic density profile and Spitzer resistivity profile in the vacuum region, the resistivity was found to have a destabilizing effect on both the kink mode and on the ballooning mode. With diamagnetic effects included, the intermediate-n and high-n ballooning modes can be totally stabilized for finite edge current density.

  8. The Effect of Plasma Shape on H-Mode Pedestal Characteristics on DIII-D

    International Nuclear Information System (INIS)

    T.H. Osborne; J.R. Ferron; R.J. Groebner; L.L. Lao; A.W. Leonard; R. Maingi; R.L. Miller; A.D. Turnbull; M.R. Wade; J.G. Watkins

    1999-01-01

    The characteristics of the H-mode are studied in discharges with varying triangularity and squareness. The pressure at the top of the H-mode pedestal increases strongly with triangularity primarily due to an increase in the margin by which the edge pressure gradient exceeds the ideal ballooning mode first stability limit. Two models are considered for how the edge may exceed the ballooning mode limit. In one model [1], access to the ballooning mode second stable regime allows the edge pressure gradient and associated bootstrap current to continue to increase until an edge localized, low toroidal mode number, ideal kink mode is destabilized. In the second model [2], the finite width of the H-mode transport barrier, and diamagnetic effects raise the pressure gradient limit above the ballooning mode limit. We observe a weak inverse dependence of the width of the H-mode transport barrier, Δ, on triangularity relative to the previously obtained [3] scaling Δ ∞ (β P PED ) 1/2 . The energy loss for Type I ELMs increases with triangularity in proportion to the pedestal energy increase. The temperature profile is found to respond stiffly to changes in T PED at low temperature, while at high temperature the response is additive. The response of the density profile is also found to play a role in the response of the total stored energy to changes in the W PED

  9. Linear calculations of edge current driven kink modes with BOUT++ code

    International Nuclear Information System (INIS)

    Li, G. Q.; Xia, T. Y.; Xu, X. Q.; Snyder, P. B.; Turnbull, A. D.; Ma, C. H.; Xi, P. W.

    2014-01-01

    This work extends previous BOUT++ work to systematically study the impact of edge current density on edge localized modes, and to benchmark with the GATO and ELITE codes. Using the CORSICA code, a set of equilibria was generated with different edge current densities by keeping total current and pressure profile fixed. Based on these equilibria, the effects of the edge current density on the MHD instabilities were studied with the 3-field BOUT++ code. For the linear calculations, with increasing edge current density, the dominant modes are changed from intermediate-n and high-n ballooning modes to low-n kink modes, and the linear growth rate becomes smaller. The edge current provides stabilizing effects on ballooning modes due to the increase of local shear at the outer mid-plane with the edge current. For edge kink modes, however, the edge current does not always provide a destabilizing effect; with increasing edge current, the linear growth rate first increases, and then decreases. In benchmark calculations for BOUT++ against the linear results with the GATO and ELITE codes, the vacuum model has important effects on the edge kink mode calculations. By setting a realistic density profile and Spitzer resistivity profile in the vacuum region, the resistivity was found to have a destabilizing effect on both the kink mode and on the ballooning mode. With diamagnetic effects included, the intermediate-n and high-n ballooning modes can be totally stabilized for finite edge current density

  10. Heparin kinetics

    International Nuclear Information System (INIS)

    Swart, C.A.M. de.

    1983-01-01

    The author has studied the kinetics of heparin and heparin fractions after intravenous administration in humans and in this thesis the results of this study are reported. Basic knowledge about the physico-chemical properties of heparin and its interactions with proteins resulting in anticoagulant and lipolytic effects are discussed in a review (chapter II), which also comprises some clinical aspects of heparin therapy. In chapter III the kinetics of the anticoagulant effect are described after intravenous administration of five commercial heparin preparations. A mathematical model is presented that fits best to these kinetics. The kinetics of the anticoagulant and lipolytic effects after intravenous injection of various 35 S-radiolabelled heparin fractions and their relationship with the disappearance of the radiolabel are described in chapter IV. Chapter V gives a description of the kinetics of two radiolabels after injection of in vitro formed complexes consisting of purified, 125 I-radiolabelled antithrombin III and various 35 S-radiolabelled heparin fractions. (Auth.)

  11. Application of Electrocautery Needle Knife Combined with Balloon Dilatation versus Balloon Dilatation in the Treatment of Tracheal Fibrotic Scar Stenosis.

    Science.gov (United States)

    Bo, Liyan; Li, Congcong; Chen, Min; Mu, Deguang; Jin, Faguang

    Electrocautery needle knives can largely reduce scar and granulation tissue hyperplasia and play an important role in treating patients with benign stricture. The aim of this retrospective study was to evaluate the efficacy and safety of electrocautery needle knife combined with balloon dilatation versus balloon dilatation alone in the treatment of tracheal stenosis caused by tracheal intubation or tracheotomy. We retrospectively analysed the clinical data of 43 patients with tracheal stenosis caused by tracheotomy or tracheal intubation in our department from January 2013 to January 2016. Among these 43 patients, 23 had simple web-like stenosis and 20 had complex steno sis. All patients were treated under general anaesthesia, and the treatment methods were (1) balloon dilatation alone, (2) needle knife excision of fibrotic tissue combined with balloon dilatation, and (3) needle knife radial incision of fibrotic tissue combined with balloon dilatation. After treatment the symptoms, such as shortness of breath, were markedly improved immediately in all cases. The stenosis degree of patients who were treated with the elec-trocautery needle knife combined with balloon dilatation had better improvement compared with that of those treated with balloon dilatation treatment alone after 3 months (0.45 ± 0.04 vs. 0.67 ± 0.05, p knife combined with balloon dilatation is an effective and safe treatment for tracheal fibrotic stenosis compared with balloon dilatation alone. © 2017 S. Karger AG, Basel.

  12. The isotopic composition of methane in the stratosphere: high-altitude balloon sample measurements

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2011-12-01

    Full Text Available The isotopic composition of stratospheric methane has been determined on a large suite of air samples from stratospheric balloon flights covering subtropical to polar latitudes and a time period of 16 yr. 154 samples were analyzed for δ13C and 119 samples for δD, increasing the previously published dataset for balloon borne samples by an order of magnitude, and more than doubling the total available stratospheric data (including aircraft samples published to date. The samples also cover a large range in mixing ratio from tropospheric values near 1800 ppb down to only 250 ppb, and the strong isotope fractionation processes accordingly increase the isotopic composition up to δ13C = −14‰ and δD = +190‰, the largest enrichments observed for atmospheric CH4 so far. When analyzing and comparing kinetic isotope effects (KIEs derived from single balloon profiles, it is necessary to take into account the residence time in the stratosphere in combination with the observed mixing ratio and isotope trends in the troposphere, and the range of isotope values covered by the individual profile. The isotopic composition of CH4 in the stratosphere is affected by both chemical and dynamical processes. This severely hampers interpretation of the data in terms of the relative fractions of the three important sink mechanisms (reaction with OH, O(1D and Cl. It is shown that a formal sink partitioning using the measured data severely underestimates the fraction removed by OH, which is likely due to the insensitivity of the measurements to the kinetic fractionation in the lower stratosphere. Full quantitative interpretation of the CH4 isotope data in terms of the three sink reactions requires a global model.

  13. Transition from resistive ballooning to neoclassical magnetohydrodynamic pressure-gradient-driven instability

    International Nuclear Information System (INIS)

    Spong, D.A.; Shaing, K.C.; Carreras, B.A.; Charlton, L.A.; Callen, J.D.; Garcia, L.

    1988-10-01

    The linearized neoclassical magnetohydrodynamic equations, including perturbed neoclassical flows and currents, have been solved for parameter regimes where the neoclassical pressure-gradient-driven instability becomes important. This instability is driven by the fluctuating bootstrap current term in Ohm's law. It begins to dominate the conventional resistive ballooning mode in the banana-plateau collisionality regime [μ/sub e//ν/sub e/ /approximately/ √ε/(1 + ν/sub *e/) > ε 2 ] and is characterized by a larger radial mode width and higher growth rate. The neoclassical instability persists in the absence of the usual magnetic field curvature drive and is not significantly affected by compressibility. Scalings with respect to β, n (toroidal mode number), and μ (neoclassical viscosity) are examined using a large-aspect-ratio, three-dimensional initial-value code that solves linearized equations for the magnetic flux, fluid vorticity, density, and parallel ion flow velocity in axisymmetric toroidal geometry. 13 refs., 10 figs

  14. Thrombus aspiration catheter is a Dottering balloon

    Directory of Open Access Journals (Sweden)

    D. Sheshagiri Rao

    2016-07-01

    Full Text Available Coronary angiogram in a young man with history of STEMI with delayed presentation revealed subtotal occlusion of left anterior descending artery (LAD with large thrombotic filling defect distal to the critical lesion. PCI was preferred without delay because of ongoing chest pain. Several runs of thrombus aspiration failed to detect any visible thrombus. However, the immediate angiogram after thrombus aspiration showed complete distal embolization of the thrombus which could have been achieved by Dottering or balloon dilatation. In contrary to the general perception, does thrombus aspiration push more thrombus than it can aspirate?

  15. Thrombus aspiration catheter is a Dottering balloon.

    Science.gov (United States)

    Sheshagiri Rao, D; Barik, Ramachandra; Prasad, Akula Siva

    2016-01-01

    Coronary angiogram in a young man with history of STEMI with delayed presentation revealed subtotal occlusion of left anterior descending artery (LAD) with large thrombotic filling defect distal to the critical lesion. PCI was preferred without delay because of ongoing chest pain. Several runs of thrombus aspiration failed to detect any visible thrombus. However, the immediate angiogram after thrombus aspiration showed complete distal embolization of the thrombus which could have been achieved by Dottering or balloon dilatation. In contrary to the general perception, does thrombus aspiration push more thrombus than it can aspirate? Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  16. Retrograde transurethral balloon dilation of the prostate

    International Nuclear Information System (INIS)

    Castaneda, F.; Reddy, P.; Wasserman, N.F.; Lund, G.; Hulbert, J.; Hunter, D.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1986-01-01

    A series of patients with documented benign prostatic hypertrophy evaluated by urodynamic studies, voiding cystourethrography, retrograde urethrography, and MR imaging underwent dilation performed using a retrograde transurethral approach with 25-mm balloon dilators inflated at a pressure of 3-4 atm for 10 minutes. Immediately after the procedure, retrograde and voiding cystourethrography as well as MR imaging were performed. A Foley catheter was left in place for 24 hours. Complete relief of symptoms has occurred in all of the patients during the follow-up period. No significant complications other than transient hematuria resulted from the procedure. Results of the comparison studies and of MR imaging are discussed

  17. Flight Qualification of the NASA's Super Pressure Balloon

    Science.gov (United States)

    Cathey, Henry; Said, Magdi; Fairbrother, Debora

    Designs of new balloons to support space science require a number of actual flights under various flight conditions to qualify them to as standard balloon flight offerings to the science community. Development of the new Super Pressure Balloon for the National Aeronautics and Space Administration’s Balloon Program Office has entailed employing new design, analysis, and production techniques to advance the state of the art. Some of these advances have been evolutionary steps and some have been revolutionary steps requiring a maturing understanding of the materials, designs, and manufacturing approaches. The NASA Super Pressure Balloon development end goal is to produce a flight vehicle that is qualified to carry a ton of science instrumentation, at an altitude greater than 33 km while maintaining a near constant pressure altitude for extended periods of up to 100 days, and at any latitude on the globe. The NASA’s Balloon Program Office has pursued this development in a carefully executed incremental approach by gradually increasing payload carrying capability and increasing balloon volume to reach these end goal. A very successful test flight of a ~200,700 m3 balloon was launch in late 2008 from Antarctica. This balloon flew for over 54 days at a constant altitude and circled the Antarctic continent almost three times. A larger balloon was flown from Antarctica in early 2011. This ~422,400 m3 flew at a constant altitude for 22 days making one circuit around Antarctica. Although the performance was nominal, the flight was terminated via command to recover high valued assets from the payload. The balloon designed to reach the program goals is a ~532,200 m3 pumpkin shaped Super Pressure Balloon. A test flight of this balloon was launched from the Swedish Space Corporation’s Esrange Balloon Launch Facilities near Kiruna, Sweden on 14 August, 2012. This flight was another success for this development program. Valuable information was gained from this short test

  18. Simultaneous stent expansion/balloon deflation technique to salvage failed balloon remodeling.

    Science.gov (United States)

    Ladner, Travis R; He, Lucy; Davis, Brandon J; Froehler, Michael T; Mocco, J

    2016-04-01

    Herniation, with possible embolization, of coils into the parent vessel following aneurysm coiling remains a frequent challenge. For this reason, balloon or stent assisted embolization remains an important technique. Despite the use of balloon remodeling, there are occasions where, on deflation of the balloon, some coils, or even the entire coil mass, may migrate. We report the successful use of a simultaneous adjacent stent deployment bailout technique in order to salvage coil prolapse during balloon remodeling in three patients. Case No 1 was a wide neck left internal carotid artery bifurcation aneurysm, measuring 9 mm×7.9 mm×6 mm with a 5 mm neck. Case No 2 was a complex left superior hypophyseal artery aneurysm, measuring 5.3 mm×4 mm×5 mm with a 2.9 mm neck. Case No 3 was a ruptured right posterior communicating artery aneurysm, measuring 4 mm×4 mm×4.5 mm with a 4 mm neck. This technique successfully returned the prolapsed coil mass into the aneurysm sac in all cases without procedural complications. The closed cell design of the Enterprise VRD (Codman and Shurtleff Inc, Raynham, Massachusetts, USA) makes it ideal for this bailout technique, by allowing the use of an 0.021 inch delivery catheter (necessary for simultaneous access) and by avoiding the possibility of an open cell strut getting caught on the deflated balloon. We hope this technique will prove useful to readers who may find themselves in a similar predicament. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. Two-dimensional aspects of toroidal drift waves in the ballooning representation

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.; Zhang, X.D.

    1992-01-01

    By systematically doing the higher-order theory, the predictions of the conventional ballooning theory (CBT) are examined for nonideal systems. For the complex solvability condition to be satisfied, radial variation of the lowest-order mode amplitude needs to be invoked. It turns out, however, that even this procedure with its concomitant modifications of eigenvalues and eigenstructures, is not sufficient to justify the predictions of many CBT solutions; only a small set of the CBT solutions could be put on firm footing. To demonstrate this work's general conclusions, theoretical and numerical results are presented for a system of fluid drift waves with nonadiabatic electron response

  20. Two dimensional aspects of toroidal drift waves in the ballooning representation

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.; Zhang, X.D.

    1992-05-01

    By systematically doing the higher order theory, the predictions of the conventional ballooning theory (CBT) are examined for non-ideal systems. For the complex solvability condition to be satisfied, radial variation of the lowest order mode amplitude needs to be invoked. It turns out, however, that even this procedure with its concomitant modifications of eigenvalues and eigenstructures, is not sufficient to justify the predictions of many CBT solutions; only a small set of CBT solutions could be put on a firm footing. To demonstrate our general conclusions, theoretical and numerical results are presented for system of fluid drift waves non-adiabatic electron response

  1. Reynolds stress of localized toroidal modes

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.

    1995-02-01

    An investigation of the 2D toroidal eigenmode problem reveals the possibility of a new consistent 2D structure, the dissipative BM-II mode. In contrast to the conventional ballooning mode, the new mode is poloidally localized at π/2 (or -π/2), and possesses significant radial asymmetry. The radial asymmetry, in turn, allows the dissipative BM-II to generate considerably larger Reynolds stress as compared to the standard slab drift type modes. It is also shown that a wide class of localized dissipative toroidal modes are likely to be of the dissipative BM-II nature, suggesting that at the tokamak edge, the fluctuation generated Reynolds stress (a possible source of poloidal flow) can be significant

  2. Reynolds stress of localized toroidal modes

    International Nuclear Information System (INIS)

    Zhang, Y.Z.; Mahajan, S.M.

    1995-01-01

    An investigation of the 2D toroidal eigenmode problem reveals the possibility of a new consistent 2D structure, the dissipative BM-II mode. In contrast to the conventional ballooning mode, the new mode is poloidally localized at π/2 (or -π/2), and possesses significant radial asymmetry. The radial asymmetry, in turn, allows the dissipative BM-II to generate considerably larger Reynolds stress as compared to the standard slab drift type modes. It is also shown that a wide class of localized dissipative toroidal modes are likely to be of the dissipative BM-II nature, suggesting that at the tokamak edge, the fluctuation generated Reynolds stress (a possible source of poloidal flow) can be significant. (author). 15 refs

  3. Theory-based transport simulations of TFTR L-mode temperature profiles

    International Nuclear Information System (INIS)

    Bateman, G.

    1991-01-01

    The temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient (η i ) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the periphery. Within the context of this transport model and the TFTR simulations reported here, the scaling of confinement with heating power comes from the temperature dependence of the η i and trapped electron modes, while the scaling with current comes mostly from resistive ballooning modes. 24 refs., 16 figs., 3 tabs

  4. External caps: An approach to stress reduction in balloons

    Science.gov (United States)

    Hazlewood, K. H.

    Recent findings of the catastrophic balloon failures investigation in the U.S.A. indicate that very large gross inflations, in balloons using present design philosophy, over-stress currently available materials. External caps are proposed as an economic approach to reducting those stresses to an acceptable level.

  5. Paraspinal arteriovenous malformation Onyx embolization via an Ascent balloon.

    Science.gov (United States)

    Martínez-Galdámez, Mario; Rodriguez-Arias, Carlos A; Utiel, Elena; Arreba, Emilio; Gonzalo, Miguel; Arenillas, Juan F

    2014-04-01

    Purely extradural lumbar spinal arteriovenous malformations (AVMs) are rare lesions that have diverse presentations and imaging features. The treatment of a symptomatic high flow paraspinal AVM with multiple feeders remains a challenge. We report the first use of an Ascent balloon (dual lumen balloon catheter) to deliver Onyx with excellent penetration to a paraspinal AVM.

  6. Kinetic Interface

    DEFF Research Database (Denmark)

    2009-01-01

    A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....

  7. The ballooning of fuel cladding tubes: theory and experiment

    International Nuclear Information System (INIS)

    Shewfelt, R.S.W.

    1988-01-01

    Under some conditions, fuel clad ballooning can result in considerable strain before rupture. If ballooning were to occur during a loss-of-coolant accident (LOCA), the resulting substantial blockage of the sub-channel would restrict emergency core cooling. However, circumferential temperature gradients that would occur during a LOCA may significantly limit the average strain at failure. Understandably, the factors that control ballooning and rupture of fuel clad are required for the analysis of a LOCA. Considerable international effort has been spent on studying the deformation of Zircaloy fuel cladding under conditions that would occur during a LOCA. This effort has established a reasonable understanding of the factors that control the ballooning, failure time, and average failure strain of fuel cladding. In this paper, both the experimental and theoretical studies of the fuel clad ballooning are reviewed. (author)

  8. Balloon catheter dilation of benign esophageal stenosis in children

    International Nuclear Information System (INIS)

    Fan Guoping; Yu Juming; Zhong Weixing; Zhu Ming; Wu Yeming; Shi Chengren

    2001-01-01

    Objective: To evaluate the methods and effect of balloon catheter dilation of benign esophageal stenosis in children. Methods: 9 cases had an anastomotic stenosis after surgical correction of esophageal atresia; 11 cases of esophageal stenosis due to ingestion of caustics; one case had an lower esophageal stenosis after Nissen surgery and one case after gastro-esophagoplasty. Age ranged from 17 days to 7 years. Each case had a barium esophagram before balloon dilation. The balloon size varied from 3 to 10 mm in diameter. Results: 21 cases were successful after dilation of balloon catheter. There were no esophageal perforation and complications. The satisfactory results maintained from six months to thirty months. Conclusions: Balloon catheter dilation is a simple, safe and reliable method for the treatment of benign esophageal strictures in children as the first choice

  9. A Rare and Serious Unforeseen Complication of Cutting Balloon Angioplasty

    Directory of Open Access Journals (Sweden)

    Praveen Vemula

    2014-01-01

    Full Text Available Cutting balloon angioplasty (CBA is one of the adept ways of treating “in-stent restenosis.” Various complications related to cutting balloon angioplasty have been reported including arterial rupture, delayed perforation and fracture of microsurgical blades. Here we report a very unusual and inadvertent extraction of a stent previously deployed in the ramus intermedius coronary branch by a cutting balloon catheter. This required repeat stenting of the same site for an underlying dissection. Even though stent extraction is a rare complication it can be serious due to dissection, perforation, and closure of the artery. Physicians performing coronary artery interventions would need to be aware of this rare and serious complication especially if any difficulty is encountered while withdrawing the cutting balloon. Therefore, after removal, cutting balloon should be examined thoroughly for possible stent dislodgment or extraction when used for “in-stent restenosis.”

  10. Balloon observation of gamma-ray burst

    International Nuclear Information System (INIS)

    Nishimura, Jun; Fujii, Masami; Yamagami, Takamasa; Oda, Minoru; Ogawara, Yoshiaki

    1978-01-01

    Cosmic gamma-ray burst is an interesting high energy astrophysical phenomenon, but the burst mechanism has not been well understood. Since 1975, long duration balloon flight has been conducted to search for gamma-ray bursts and to determine the source locations. A rotating cross-modulation collimator was employed to determine the locations of sources, and four NaI(Tl) scintillation counters were employed to detect hard X-ray with energy from 20 to 200 keV. The balloon light was performed at altitude of 8.3 mb from September 28, 1977, and the observation time of 79 hours was achieved. In this experiment, the monitor counter was not mounted. The count increase was observed at 16 h 22 m 31 s JST on October 1, 1977. The event disappeared after 1 sec. The total flux is estimated to be 1.6 x 10 -6 erg/cm 2 sec at the top of the atmosphere. When this event was observed, the solar-terrestrial environment was also quiet. Thus, this event was attributed to a small gamma-ray burst. Unfortunately, the duration of the burst was so short that the position of the burst source was not able to be determined. (Yoshimori, M.)

  11. New concepts for interplanetary balloons and blimps, particularly for Titan

    Science.gov (United States)

    Nott, J.

    This paper proposes novel approaches for balloons for planets Titan BALLUTE A balloon or blimp arriving at a planet or moon with an atmosphere might inflate falling under a parachute or after landing Neither is ideal In both cases the envelope must include qualities needed for inflation as well as those for flight A ballute BALLoon parachUTE could be used thus a ballute is like a hot air balloon with a large mouth Initially it fills by ram pressure descending through an atmosphere As proposed it would then be heated by solid propellant It would stop descending and float level with hot air lift It is now a perfect location for inflation without wind or movement through the atmosphere and away from the uncertainties of the surface A ballute could be used over several bodies in the solar system BALLOONS FOR LOW TEMPERATURES Flight in very low temperatures is also discussed Conditions are so different that it is useful to examine basic factors These apply for any planet with low temperature and weather calm enough for balloons or blimps First for terrestrial hot air balloons thermal radiation is usually the dominant way heat is lost But radiation rises with the 4th power of absolute temperature At Titan radiation will be one or two orders of magnitude smaller Also the dense atmosphere allows small balloons small temperature differences So convection is small It appears a hot air balloon can easily be heated by a radioactive source likely carried to make electricity Pinholes are not important in such a balloon

  12. WKB theory for high-n modes in axisymmetric toroidal plasmas

    International Nuclear Information System (INIS)

    Dewar, R.L.; Chance, M.S.; Glasser, A.H.; Greene, J.M.; Frieman, E.A.

    1979-09-01

    It is demonstrated that the low-frequency, k/sub parallel//k/sub perpendicular/ approx. = 0 normal modes of an axisymmetric plasma, at large but finite toroidal mode number n, can be obtained by solving a novel WKB problem involving an infinite number of branches. Formulae for the frequencies of periodic normal modes are derived. The analysis is performed in the context of an ideal MHD model, and comparison is made with numerical ballooning mode results

  13. Are drug-coated balloons cost effective for femoropopliteal occlusive disease? A comparison of bare metal stents and uncoated balloons.

    Science.gov (United States)

    Poder, Thomas G; Fisette, Jean-François

    2016-07-01

    To perform a cost-effectiveness analysis to help hospital decision-makers with regard to the use of drug-coated balloons compared with bare metal stents and uncoated balloons for femoropopliteal occlusive disease. Clinical outcomes were extracted from the results of meta-analyses already published, and cost units are those used in the Quebec healthcare network. The literature review was limited to the last four years to obtain the most recent data. The cost-effectiveness analysis was based on a 2-year perspective, and risk factors of reintervention were considered. The cost-effectiveness analysis indicated that drug-coated balloons were generally more efficient than bare metal stents, particularly for patients with higher risk of reintervention (up to CAD$1686 per patient TASC II C or D). Compared with uncoated balloons, results indicated that drug-coated balloons were more efficient if the reintervention rate associated with uncoated balloons is very high and for patients with higher risk of reintervention (up to CAD$3301 per patient). The higher a patient's risk of reintervention, the higher the savings associated with the use of a drug-coated balloon will be. For patients at lower risk, the uncoated balloon strategy is still recommended as a first choice for endovascular intervention.

  14. Theory of anomalous transport in H-mode plasmas

    International Nuclear Information System (INIS)

    Itoh, S.; Itoh, K.; Fukuyama, A.; Yagi, M.

    1993-05-01

    Theory of the anomalous transport is developed, and the unified formula for the L- and H-mode plasmas is presented. The self-sustained ballooning-mode turbulence is solved in the presence of the inhomogeneous radial electric field, E r . Reductions in transport coefficients and the amplitude and decorrelation length of fluctuations due to E r ' are quantitatively analyzed. Combined with the E r -bifurcation model, the thickness of the transport barrier is simultaneously determined. (author)

  15. Effect of intra-aortic balloon pump on coronary blood flow during different balloon cycles support: A computer study.

    Science.gov (United States)

    Aye, Thin Pa Pa; Htet, Zwe Lin; Singhavilai, Thamvarit; Naiyanetr, Phornphop

    2015-01-01

    Intra-aortic balloon pump (IABP) has been used in clinical treatment as a mechanical circulatory support device for patients with heart failure. A computer model is used to study the effect on coronary blood flow (CBF) with different balloon cycles under both normal and pathological conditions. The model of cardiovascular and IABP is developed by using MATLAB SIMULINK. The effect on coronary blood flow has been studied under both normal and pathological conditions using different balloon cycles (balloon off; 1:4; 1:2; 1:1). A pathological heart is implemented by reducing the left ventricular contractility. The result of this study shows that the rate of balloon cycles is related to the level of coronary blood flow.

  16. Effects of radial envelope modulations on the collisionless trapped-electron mode in tokamak plasmas

    Science.gov (United States)

    Chen, Hao-Tian; Chen, Liu

    2018-05-01

    Adopting the ballooning-mode representation and including the effects of radial envelope modulations, we have derived the corresponding linear eigenmode equation for the collisionless trapped-electron mode in tokamak plasmas. Numerical solutions of the eigenmode equation indicate that finite radial envelope modulations can affect the linear stability properties both quantitatively and qualitatively via the significant modifications in the corresponding eigenmode structures.

  17. A sliding mode observer for hemodynamic characterization under modeling uncertainties

    KAUST Repository

    Zayane, Chadia

    2014-06-01

    This paper addresses the case of physiological states reconstruction in a small region of the brain under modeling uncertainties. The misunderstood coupling between the cerebral blood volume and the oxygen extraction fraction has lead to a partial knowledge of the so-called balloon model describing the hemodynamic behavior of the brain. To overcome this difficulty, a High Order Sliding Mode observer is applied to the balloon system, where the unknown coupling is considered as an internal perturbation. The effectiveness of the proposed method is illustrated through a set of synthetic data that mimic fMRI experiments.

  18. Stability of short wavelength tearing and twisting modes

    International Nuclear Information System (INIS)

    Waelbroeck, F.L.

    1998-01-01

    The stability and mutual interaction of tearing and twisting modes in a torus is governed by matrices that generalize the well-known Δ' stability index. The diagonal elements of these matrices determine the intrinsic stability of modes that reconnect the magnetic field at a single resonant surface. The off-diagonal elements indicate the strength of the coupling between the different modes. The author shows how the elements of these matrices can be evaluated, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. The author applies the results by calculating the tearing and twisting Δ' for a model high-beta equilibrium with circular flux surfaces

  19. Detecting Seismic Infrasound Signals on Balloon Platforms

    Science.gov (United States)

    Krishnamoorthy, S.; Komjathy, A.; Cutts, J. A.; Pauken, M.; Garcia, R.; Mimoun, D.; Jackson, J. M.; Kedar, S.; Smrekar, S. E.; Hall, J. L.

    2017-12-01

    The determination of the interior structure of a planet requires detailed seismic investigations - a process that entails the detection and characterization of seismic waves due to geological activities (e.g., earthquakes, volcanoes, etc.). For decades, this task has primarily been performed on Earth by an ever-expanding network of terrestrial seismic stations. However, on planets such as Venus, where the surface pressure and temperature can reach as high as 90 atmospheres and 450 degrees Celsius respectively, placing seismometers on the planet's surface poses a vexing technological challenge. However, the upper layers of the Venusian atmosphere are more benign and capable of hosting geophysical payloads for longer mission lifetimes. In order to achieve the aim of performing geophysical experiments from an atmospheric platform, JPL and its partners (ISAE-SUPAERO and California Institute of Technology) are in the process of developing technologies for detection of infrasonic waves generated by earthquakes from a balloon. The coupling of seismic energy into the atmosphere critically depends on the density differential between the surface of the planet and the atmosphere. Therefore, the successful demonstration of this technique on Earth would provide ample reason to expect success on Venus, where the atmospheric impedance is approximately 60 times that of Earth. In this presentation, we will share results from the first set of Earth-based balloon experiments performed in Pahrump, Nevada in June 2017. These tests involved the generation of artificial sources of known intensity using a seismic hammer and their detection using a complex network of sensors, including highly sensitive micro-barometers suspended from balloons, GPS receivers, geophones, microphones, and seismometers. This experiment was the first of its kind and was successful in detecting infrasonic waves from the earthquakes generated by the seismic hammer. We will present the first comprehensive analysis

  20. Microcontroller uses in Long-Duration Ballooning

    Science.gov (United States)

    Jones, Joseph

    This paper discusses how microcontrollers are being utilized to fulfill the demands of long duration ballooning (LDB) and the advantages of doing so. The Columbia Scientific Balloon Facility (CSBF) offers the service of launching high altitude balloons (120k ft) which provide an over the horizon telemetry system and platform for scientific research payloads to collect data. CSBF has utilized microcontrollers to address multiple tasks and functions which were previously performed by more complex systems. A microcontroller system has been recently developed and programmed in house to replace our previous backup navigation system which is used on all LDB flights. A similar microcontroller system was developed to be independently launched in Antarctica before the actual scientific payload. This system's function is to transmit its GPS position and a small housekeeping packet so that we can confirm the upper level float winds are as predicted from satellite derived models. Microcontrollers have also been used to create test equipment to functionally check out the flight hardware used in our telemetry systems. One test system which was developed can be used to quickly determine if our communication link we are providing for the science payloads is functioning properly. Another system was developed to provide us with the ability to easily determine the status of one of our over the horizon communication links through a closed loop system. This test system has given us the capability to provide more field support to science groups than we were able to in years past. The trend of utilizing microcontrollers has taken place for a number of reasons. By using microcontrollers to fill these needs, it has given us the ability to quickly design and implement systems which meet flight critical needs, as well as perform many of the everyday tasks in LDB. This route has also allowed us to reduce the amount of time required for personnel to perform a number of the tasks required

  1. Kinetics and

    Directory of Open Access Journals (Sweden)

    Mojtaba Ahmadi

    2016-11-01

    Full Text Available The aqueous degradation of Reactive Yellow 84 (RY84 by potassium peroxydisulfate (K2S2O8 has been studied in laboratory scale experiments. The effect of the initial concentrations of potassium peroxydisulfate and RY84, pH and temperature on RY84 degradation were also examined. Experimental data were analyzed using first and second-order kinetics. The degradation kinetics of RY84 of the potassium peroxydisulfate process followed the second-order reaction kinetics. These rate constants have an extreme values similar to of 9.493 mM−1min−1 at a peroxydisulfate dose of 4 mmol/L. Thermodynamic parameters such as activation (Ea and Gibbs free energy (ΔG° were also evaluated. The negative value of ΔGo and Ea shows the spontaneous reaction natural conditions and exothermic nature.

  2. Boston's balloon dilatation for treatment of cardiac achalasia

    International Nuclear Information System (INIS)

    Yin Jianguo; Song Jinwen; Yang Yan; Liu Xiaohong; Fu Zhiming; Zhang Yaqin

    2001-01-01

    Objective: To review and summarize effectiveness and method of the Boston's balloon dilation in cardiac achalasia. Methods: The intensified guide wire was inserted into stomach through mouth cavity under TV control. The Boston's balloon was inserted to the cardiac stricture through the guide wire and dilatated with 15% contrast medium with to a maximum diameter for five minutes and then the balloon was dilatated again for 3-5 minutes, all together for 3-4 times. The severe stricture must be pre-dilatated with 20-25 mm diameter balloon. Results: The balloon insertion was technically successful in all 26 patients. The once success of balloon dilation was achieved in 24 patients and twice in other 2. Follow-up time was from 2 weeks to 31 months (mean 10.6 months). Recurrent stenosis had not occurred in all patients. Remission rate of dysphagia was 100%. Esophageal reflux occurred in 3 patients. Conclusions: The Boston's balloon dilatation is simple and effective for treatment of cardiac achalasia. The method sometimes may replace surgical procedure

  3. Rectal Balloon for the Immobilization of the Prostate Internal Motion

    International Nuclear Information System (INIS)

    Lee, Sang Kyu; Beak, Jong Geal; Kim, Joo Ho; Jeon, Byong Chul; Cho, Jeong Hee; Kim, Dong Wook; Song, Tae Soo; Cho, Jae Ho; Na, Soo Kyong

    2005-01-01

    The using of endo-rectal balloon has proposed as optimal method that minimized the motion of prostate and the dose of rectum wall volume for treated prostate cancer patients, so we make the customized rectal balloon device. In this study, we analyzed the efficiency of the Self-customized rectal balloon in the aspects of its reproducibility. In 5 patients, for treatment planning, each patient was acquired CT slice images in state of with and without rectal balloon. Also they had CT scanning same repeated third times in during radiation treatment (IMRT). In each case, we analyzed the deviation of rectal balloon position and verified the isodose distribution of rectum wall at closed prostate. Using the rectal balloon, we minimized the planning target volume (PTV) by decreased the internal motion of prostate and overcome the dose limit of radiation therapy in prostate cancer by increased the gap between the rectum wall and high dose region. The using of rectal balloon, although, was reluctant to treat by patients. View a point of immobilization of prostate internal motion and dose escalation of GTV (gross tumor volume), its using consider large efficient for treated prostate cancer patients.

  4. QUANTITATIVE TESTS OF ELMs AS INTERMEDIATE n PEELING-BALOONING MODES

    International Nuclear Information System (INIS)

    LAO, LL; SNYDER, PB; LEONARD, AW; OIKAWA, T; OSBORNE, TH; PETRIE, TW; FERRON, JR; GROEBNER, RJ; HORTON, LD; KAMADA, Y; MURAKAMI, M; SAARELMA, S; STJOHN, HE; TURNBULL, AD; WILSON, HR

    2003-01-01

    A271 QUANTITATIVE TESTS OF ELMS AS INTERMEDIATE N PEELING-BALOONING MODES. Several testable features of the working model of edge localized modes (ELMs) as intermediate toroidal mode number peeling-ballooning modes are evaluated quantitatively using DIII-D and JT-60U experimental data and the ELITE MHD stability code. These include the hypothesis that ELM sizes are related to the radial widths of the unstable MHD modes, the unstable modes have a strong ballooning character localized in the outboard bad curvature region, and ELM size generally becomes smaller at high edge collisionality. ELMs are triggered when the growth rates of the unstable MHD modes become significantly large. These testable features are consistent with many ELM observations in DIII-D and JT-60U discharges

  5. Granulocyte kinetics

    International Nuclear Information System (INIS)

    Peters, A.M.; Lavender, J.P.; Saverymuttu, S.H.

    1985-01-01

    By using density gradient materials enriched with autologous plasma, the authors have been able to isolate granulocutes from other cellular elements and label them with In-111 without separation from a plasma environment. The kinetic behavior of these cells suggests that phenomena attributed to granulocyte activation are greatly reduced by this labeling. Here, they review their study of granulocyte kinetics in health and disease in hope of quantifying sites of margination and identifying principal sites of destruction. The three principle headings of the paper are distribution, life-span, and destruction

  6. Balloon-tipped flow-directed catheters

    International Nuclear Information System (INIS)

    Ganz, P.; Swan, H.J.C.; Ganz, W.

    1986-01-01

    Diagnostic catheterization of the right side of the heart with semirigid cardiac catheters requires fluoroscopic guidance and substantial skill. Abnormal positions of the heart chambers and of the great vessels associated with cardiac dilatation or with congenital malformation present difficulties even to experienced laboratory cardiologists. These problems have been largely overcome by the introduction of balloon tipped flow directed catheters, which allow for rapid and relatively safe catheterization of the pulmonary artery without fluoroscopy. It was through the application of these catheters in the intensive care unit that the many pitfalls in the clinical assessment of hemodynamic disturbances became apparent. Although S3 gallop sounds may be useful in the clinical recognition of chronic ventricular failure, their presence or absence has limited predictive value in estimating left ventricular filling pressure in myocardial infarction. Information derived from right heart catheterization is often pivotal in the evaluation of hemodynamic disorders, in directing treatment, and in monitoring the results of therapy in critically ill patients

  7. Percutaneous balloon dilatation for transplant ureteral strictures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Chul [Chungnam National University School of Medicine, Taechun (Korea, Republic of); Banner, Marc P [University of Pennsylvania School of Medicine, Philadelphia (United States)

    1993-09-15

    We report 10 kidney allografted patients treated for 11 ureteral strictures with standard endourlogic balloon catheter dilatation and internal stenting between August 1979 and December 1991. They have been followed until 2 to 140 months (mean 42). We compared and analyzed the 6 successful strictures (54%) and 5 unsuccessful strictures. There was no statistically significant difference of demographic, clinical and radiologic interventional techniques between two groups. But there was slightly higher success rate in abruptly narrowed shorter fibrotic strictures in ureteroneocystomy sites than smoothly taped longer ones in other sites of the ureter. Longterm stenting by the transplantation team with cystoscopic removal of internal ureteral stents by urologists resulted in 3 cases of stent occlusion, encrustation or fracture. Exact early diagnosis of ureteral stricture with continued close follow up and proper radiologic interventional procedure with optimal stenting period may increase the success rate and still provide an alternative to surgery.

  8. High Energy Antimatter Telescope (HEAT) Balloon Experiment

    Science.gov (United States)

    Beatty, J. J.

    1995-01-01

    This grant supported our work on the High Energy Antimatter Telescope(HEAT) balloon experiment. The HEAT payload is designed to perform a series of experiments focusing on the cosmic ray positron, electron, and antiprotons. Thus far two flights of the HEAT -e+/- configuration have taken place. During the period of this grant major accomplishments included the following: (1) Publication of the first results of the 1994 HEAT-e+/- flight in Physical Review Letters; (2) Successful reflight of the HEAT-e+/- payload from Lynn Lake in August 1995; (3) Repair and refurbishment of the elements of the HEAT payload damaged during the landing following the 1995 flight; and (4) Upgrade of the ground support equipment for future flights of the HEAT payload.

  9. Nonlinear MHD and energetic particle modes in stellarators

    International Nuclear Information System (INIS)

    Strauss, H.R.

    2002-01-01

    The M3D code has been applied to ideal, resistive, two fluid, and hybrid simulations of compact quasi axisymmetric stellarators. When beta exceeds a threshold, low poloidal mode number (m=6∼18) modes grow exponentially, clearly distinguishable from the equilibrium evolution. Simulations of NCSX have beta limits are significantly higher than the infinite mode number ballooning limits. In the presence of resistivity, these modes occur well below the ideal limit. Their growth rate scaling with resistivity is similar to tearing modes. With sufficient viscosity, the growth rate becomes slow enough to allow calculations of magnetic island evolution. Hybrid gyrokinetic simulations with energetic particles indicate that global shear Alfven TAE - like modes can be destabilized in stellarators. Computations in a two - period compact stellarator obtained a predominantly n=1 toroidal mode with about the expected TAE frequency. Work is in progress to study fast ion-driven Alfven modes in NCSX. (author)

  10. Angiographic assessment of initial balloon angioplasty results.

    Science.gov (United States)

    Gardiner, Geoffrey A; Sullivan, Kevin L; Halpern, Ethan J; Parker, Laurence; Beck, Margaret; Bonn, Joseph; Levin, David C

    2004-10-01

    To determine the influence of three factors involved in the angiographic assessment of balloon angioplasty-interobserver variability, operator bias, and the definition used to determine success-on the primary (technical) results of angioplasty in the peripheral arteries. Percent stenosis in 107 lesions in lower-extremity arteries was graded by three independent, experienced vascular radiologists ("observers") before and after balloon angioplasty and their estimates were compared with the initial interpretations reported by the physician performing the procedure ("operator") and an automated quantitative computer analysis. Observer variability was measured with use of intraclass correlation coefficients and SD. Differences among the operator, observers, and the computer were analyzed with use of the Wilcoxon signed-rank test and analysis of variance. For each evaluator, the results in this series of lesions were interpreted with three different definitions of success. Estimation of residual stenosis varied by an average range of 22.76% with an average SD of 8.99. The intraclass correlation coefficients averaged 0.59 for residual stenosis after angioplasty for the three observers but decreased to 0.36 when the operator was included as the fourth evaluator. There was good to very good agreement among the three independent observers and the computer, but poor correlation with the operator (P definition of success was used. Significant differences among the operator, the three observers, and the computer were not present when the definition of success was based on less than 50% residual stenosis. Observer variability and bias in the subjective evaluation of peripheral angioplasty can have a significant influence on the reported initial success rates. This effect can be largely eliminated with the use of residual stenosis of less than 50% to define success. Otherwise, meaningful evaluation of angioplasty results will require independent panels of evaluators or

  11. Intragastric balloon for morbid obesity causing chronic gastric dilatation

    Energy Technology Data Exchange (ETDEWEB)

    Pretolesi, F.; Derchi, L.E. [Dept. of Radiology, University of Genoa (Italy); Redaelli, G.; Papagni, L. [IRCCS, Ist. Auxologico Italiano, Milan (Italy)

    2001-04-01

    We describe the radiographic findings observed in a morbidly obese and diabetic patient with an intragastric air-filled balloon introduced as a therapeutic measure to reduce food intake. The balloon was associated with chronic gastric dilatation and had to be removed 3 months after insertion. However, together with diet and behavioural therapy, it proved effective in reducing body weight and ameliorating glycaemic control. Although rarely used, intragastric balloons for the treatment of morbid obesity are still encountered in radiological practice. Radiologists must be able to recognize them and to understand their complications. (orig.)

  12. An investigation of electrostatically deposited radionuclides on latex balloons

    International Nuclear Information System (INIS)

    Price, T.; Caly, A.

    2012-01-01

    Use of Canadian Nuclear Society (CNS) education material for a community science education event to promote science awareness, science culture and literacy (Science Rendezvous 2011) lead to investigation of observed phenomena. Experiments are done on balloons that are electrostatically charged then left to collect particulate. Alpha spectroscopy was performed to identify alpha emitting radioisotopes present on the balloons. The time dependent behaviour of the activity was investigated. Additionally, the Alpha activity of the balloon was compared to Beta activity. The grounds for further investigations are proposed. (author)

  13. Analysis of Flight of Near-Space Balloon

    Science.gov (United States)

    Miller, Zech; Evans, Austin; Seyfert, James; Leadlove, Kyle; Gumina, Kaitlyn; Martell, Eric

    2015-04-01

    In December 2014, the Electronics class at Millikin University launched a balloon designed to travel into the near-space region of the atmosphere. The balloon was equipped with an instrumentation package including a camera, accelerometer, barometric pressure sensor, temperature probes, as well as a system for tracking using an Automatic Packet Reporting System (APRS). The balloon was launched from Decatur, IL, and landed in Marysville, OH, nearly 320 miles away. The students then analyzed the data from the flight and compared results to expectations.

  14. Intragastric balloon for morbid obesity causing chronic gastric dilatation

    International Nuclear Information System (INIS)

    Pretolesi, F.; Derchi, L.E.; Redaelli, G.; Papagni, L.

    2001-01-01

    We describe the radiographic findings observed in a morbidly obese and diabetic patient with an intragastric air-filled balloon introduced as a therapeutic measure to reduce food intake. The balloon was associated with chronic gastric dilatation and had to be removed 3 months after insertion. However, together with diet and behavioural therapy, it proved effective in reducing body weight and ameliorating glycaemic control. Although rarely used, intragastric balloons for the treatment of morbid obesity are still encountered in radiological practice. Radiologists must be able to recognize them and to understand their complications. (orig.)

  15. An investigation of electrostatically deposited radionuclides on latex balloons

    Energy Technology Data Exchange (ETDEWEB)

    Price, T.; Caly, A., E-mail: Terry.Price@gmail.com [Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)

    2012-07-01

    Use of Canadian Nuclear Society (CNS) education material for a community science education event to promote science awareness, science culture and literacy (Science Rendezvous 2011) lead to investigation of observed phenomena. Experiments are done on balloons that are electrostatically charged then left to collect particulate. Alpha spectroscopy was performed to identify alpha emitting radioisotopes present on the balloons. The time dependent behaviour of the activity was investigated. Additionally, the Alpha activity of the balloon was compared to Beta activity. The grounds for further investigations are proposed. (author)

  16. Balloon dilation of congenital supravalvular pulmonic stenosis in a dog.

    Science.gov (United States)

    Treseder, Julia R; Jung, SeungWoo

    2017-03-30

    Percutaneous balloon valvuloplasty is considered the standard of care for treatment of valvular pulmonic stenosis, a common congenital defect in dogs. Supravalvular pulmonic stenosis is a rare form of pulmonic stenosis in dogs and standard treatment has not been established. Although, there have been reports of successful treatment of supravalvular pulmonic stenosis with surgical and stenting techniques, there have been no reports of balloon dilation to treat dogs with this condition. Here, a case of supravalvular pulmonic stenosis diagnosed echocardiographically and angiographically in which a significant reduction in pressure gradient was achieved with balloon dilation alone is presented.

  17. Intragastric Balloon for Obesity Treatment: Safety, Tolerance, and Efficacy

    Directory of Open Access Journals (Sweden)

    Joana Ribeiro da Silva

    2017-12-01

    Full Text Available Background: Obesity is an increasing worldwide problem associated with a vast number of comorbidities. Decreasing body weight by only 5-10% has been shown to slow and even prevent the onset of obesity-related comorbidities. Between pharmacological therapy and bariatric surgery a great variety of endoscopic techniques are available, the most common being intragastric balloon (IGB. The purpose of this study was to assess the safety, tolerance, and kinetics of IGBs in weight loss. The kinetics of weight loss were evaluated in 2 different contexts and phases: after the IGB's removal and after follow-up that varied between 6 and 12 months. Successful weight loss was defined as ≥10% weight loss after 6-12 months. Methods: The study included 51 patients who had undergone Orbera® IGB placement between September 2014 and February 2016. Inclusion criteria were age between 18 and 65 years; body mass index (BMI 28-35 with severe obesity-related disorders; or BMI 35-40. The IGB was removed 6 months later. All patients were followed for a minimum period of 6-12 months. Results: Of 51 patients, 16 were excluded (7 due to intolerance and 35 patients entered the study, of which 83% were followed for more than 6-12 months. The average weight loss (WL and % excess WL (%EWL after 6 months of treatment were 11.94 kg and 42.16%, respectively. At 6-12 months, after removal of the IGB, the mean WL was 8.25 kg and %EWL was 30.27%. Nineteen patients attained a WL of ≥10% the baseline value at IGB removal and 12 maintained their weight below this threshold during the 6-12 following months. Conclusions: After temporary IGB implantation in overweight or obese individuals, a WL that was ≥10% of weight at baseline was achieved in 54.3% and sustained at 6-12 months in 41.4% of participants. IGBs are an attractive intermediate option between diet and exercise programs and bariatric surgery. In general, IGB placement is a safe and well-tolerated procedure.

  18. Lidar- and balloon-borne particle counter comparisons following recent volcanic eruptions

    Science.gov (United States)

    Hofmann, D. J.; Rosen, J. M.; Reiter, R.; Jager, H.

    1983-01-01

    Balloon-borne particle counter measurements at Laramie, Wyoming (41 deg N) are used to calculate the expected lidar backscatter at 0.694 micron wavelength from July 1979 to February 1982, a period which included at least four detectable perturbations of the stratospheric aerosol layer due to volcanic eruptions. These calculations are compared with lidar measurements conducted at Garmisch-Partenkirchen (47.5 deg N) during the same period. While the agreement is generally good using only the main mode in the particle size distribution (radius about 0.07 micron) during approximately the first 6 months following a major volcanic eruption, a measured secondary mode near 1 micron radius, when included, improves the agreement. Calculations of the expected backscatter at 25-30 km reveal that substantial number of particles diffuse into this high altitude region about 7 months after a major eruption, and these particles should be taken into account when normalizing lidar at these altitudes.

  19. Development of a New Coaxial Balloon Catheter System for Balloon-Occluded Retrograde Transvenous Obliteration (B-RTO)

    International Nuclear Information System (INIS)

    Tanoue, Shuichi; Kiyosue, Hiro; Matsumoto, Shunro; Hori, Yuzo; Okahara, Mika; Kashiwagi, Junji; Mori, Hiromu

    2006-01-01

    Purpose. To develop a new coaxial balloon catheter system and evaluate its clinical feasibility for balloon-occluded retrograde transvenous obliteration (B-RTO). Methods. A coaxial balloon catheter system was constructed with 9 Fr guiding balloon catheter and 5 Fr balloon catheter. A 5 Fr catheter has a high flexibility and can be coaxially inserted into the guiding catheter in advance. The catheter balloons are made of natural rubber and can be inflated to 2 cm (guiding) and 1 cm (5 Fr) maximum diameter. Between July 2003 and April 2005, 8 consecutive patients (6 men, 2 women; age range 33-72 years, mean age 55.5 years) underwent B-RTO using the balloon catheter system. Five percent ethanolamine oleate iopamidol (EOI) was used as sclerosing agent. The procedures, including maneuverability of the catheter, amount of injected sclerosing agent, necessity for coil embolization of collateral draining veins, and initial clinical results, were evaluated retrospectively. The occlusion rate was assessed by postcontrast CT within 2 weeks after B-RTO. Results. The balloon catheter could be advanced into the proximal potion of the gastrorenal shunt beyond the collateral draining vein in all cases. The amount of injected EOI ranged from 3 to 34 ml. Coil embolization of the collateral draining vein was required in 2 cases. Complete obliteration of gastric varices on initial follow-up CT was obtained in 7 cases. The remaining case required re-treatment that resulted in complete obstruction of the varices after the second B-RTO. No procedure-related complications were observed. Conclusion. B-RTO using the new coaxial balloon catheter is feasible. Gastric varices can be treated more simply by using this catheter system

  20. Kinetic Scale Structure of Low-frequency Waves and Fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    López, Rodrigo A.; Yoon, Peter H. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, MD 20771 (United States); Araneda, Jaime A., E-mail: rlopezh@umd.edu, E-mail: yoonp@umd.edu [Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción, Concepción (Chile)

    2017-08-10

    The dissipation of solar wind turbulence at kinetic scales is believed to be important for the heating of the corona and for accelerating the wind. The linear Vlasov kinetic theory is a useful tool for identifying various wave modes, including kinetic Alfvén, fast magnetosonic/whistler, and ion-acoustic (or kinetic slow), and their possible roles in the dissipation. However, the kinetic mode structure in the vicinity of ion-cyclotron modes is not clearly understood. The present paper aims to further elucidate the structure of these low-frequency waves by introducing discrete particle effects through hybrid simulations and Klimontovich formalism of spontaneous emission theory. The theory and simulation of spontaneously emitted low-frequency fluctuations are employed to identify and distinguish the detailed mode structures associated with ion-Bernstein modes versus quasi-modes. The spontaneous emission theory and simulation also confirm the findings of the Vlasov theory in that the kinetic Alfvén waves can be defined over a wide range of frequencies, including the proton cyclotron frequency and its harmonics, especially for high-beta plasmas. This implies that these low-frequency modes may play predominant roles even in the fully kinetic description of kinetic scale turbulence and dissipation despite the fact that cyclotron harmonic and Bernstein modes may also play important roles in wave–particle interactions.

  1. A battery-operated pilot balloon time-signal generator

    Science.gov (United States)

    Ralph H. Moltzau

    1966-01-01

    Describes the design and construction of a 1-pound, battery-operated, time-signal transmitter, which is usable with portable radio or field telephone circuits for synchronizing multi-theodolite observation of pilot balloons.

  2. OCT evaluation of directional atherectomy compared to balloon angioplasty

    International Nuclear Information System (INIS)

    Marmagkiolis, Konstantinos; Lendel, Vasili; Cilingiroglu, Mehmet

    2015-01-01

    Directional atherectomy (DA) is one of the most commonly used modalities for the treatment of obstructive femoropopliteal peripheral arterial disease (PAD), especially in patients with large and calcified atherosclerotic plaques. The effect of directional atherectomy to the vascular wall compared to balloon angioplasty by optical coherence tomography (OCT) has not been previously described. We present the first case of OCT after directional atherectomy with SilverHawk followed by angiosculpt balloon angioplasty. - Highlights: • Directional atherectomy avoids the vascular mechanical damage caused by angioplasty balloons and the exposure of stent struts or the potential of stent fracture with stents. • OCT can accurately assess the effect of endovacular interventions to the vessel wall. • Although angiographic results after directional atherectomy are acceptable, OCT use demonstrated suboptimal improvement of the MLA requiring additional balloon angioplasty. • Longer studies are needed to define whether the improved OCT results with angioplasty compared to DA may offer better clinical outcomes.

  3. OCT evaluation of directional atherectomy compared to balloon angioplasty

    Energy Technology Data Exchange (ETDEWEB)

    Marmagkiolis, Konstantinos [Citizens Memorial Hospital Heart and Vascular Institute, Bolivar, MO (United States); Lendel, Vasili [Arkansas Heart Hospital, Peripheral Vascular Institute, Little Rock, AR (United States); Cilingiroglu, Mehmet, E-mail: mcilingiroglu@yahoo.com [Arkansas Heart Hospital, Peripheral Vascular Institute, Little Rock, AR (United States); Koc University, School of Medicine, Istanbul (Turkey)

    2015-09-15

    Directional atherectomy (DA) is one of the most commonly used modalities for the treatment of obstructive femoropopliteal peripheral arterial disease (PAD), especially in patients with large and calcified atherosclerotic plaques. The effect of directional atherectomy to the vascular wall compared to balloon angioplasty by optical coherence tomography (OCT) has not been previously described. We present the first case of OCT after directional atherectomy with SilverHawk followed by angiosculpt balloon angioplasty. - Highlights: • Directional atherectomy avoids the vascular mechanical damage caused by angioplasty balloons and the exposure of stent struts or the potential of stent fracture with stents. • OCT can accurately assess the effect of endovacular interventions to the vessel wall. • Although angiographic results after directional atherectomy are acceptable, OCT use demonstrated suboptimal improvement of the MLA requiring additional balloon angioplasty. • Longer studies are needed to define whether the improved OCT results with angioplasty compared to DA may offer better clinical outcomes.

  4. Design Evolution and Methodology for Pumpkin Super-Pressure Balloons

    Science.gov (United States)

    Farley, Rodger

    The NASA Ultra Long Duration Balloon (ULDB) program has had many technical development issues discovered and solved along its road to success as a new vehicle. It has the promise of being a sub-satellite, a means to launch up to 2700 kg to 33.5 km altitude for 100 days from a comfortable mid-latitude launch point. Current high-lift long duration ballooning is accomplished out of Antarctica with zero-pressure balloons, which cannot cope with the rigors of diurnal cycles. The ULDB design is still evolving, the product of intense analytical effort, scaled testing, improved manufacturing, and engineering intuition. The past technical problems, in particular the s-cleft deformation, their solutions, future challenges, and the methodology of pumpkin balloon design will generally be described.

  5. SMEX02 Balloon-borne Radiosonde Data, Iowa

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes radiosonde measurements of upper air temperature and pressure, relative humidity, and wind direction and speed during the balloons' ascent to...

  6. OCT evaluation of directional atherectomy compared to balloon angioplasty.

    Science.gov (United States)

    Marmagkiolis, Konstantinos; Lendel, Vasili; Cilingiroglu, Mehmet

    2015-09-01

    Directional atherectomy (DA) is one of the most commonly used modalities for the treatment of obstructive femoropopliteal peripheral arterial disease (PAD), especially in patients with large and calcified atherosclerotic plaques. The effect of directional atherectomy to the vascular wall compared to balloon angioplasty by optical coherence tomography (OCT) has not been previously described. We present the first case of OCT after directional atherectomy with SilverHawk followed by angiosculpt balloon angioplasty. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Balloon dilation of congenital supravalvular pulmonic stenosis in a dog

    OpenAIRE

    Treseder, Julia R.; Jung, SeungWoo

    2017-01-01

    Percutaneous balloon valvuloplasty is considered the standard of care for treatment of valvular pulmonic stenosis, a common congenital defect in dogs. Supravalvular pulmonic stenosis is a rare form of pulmonic stenosis in dogs and standard treatment has not been established. Although, there have been reports of successful treatment of supravalvular pulmonic stenosis with surgical and stenting techniques, there have been no reports of balloon dilation to treat dogs with this condition. Here, a...

  8. Long duration balloon flights in the middle stratosphere

    Science.gov (United States)

    Malaterre, P.

    1993-02-01

    Research and development performed by the French Space Agency (CNES) over the past 10 years has given the scientific community the Infrared Montgolfiere, a balloon capable of lifting 50-kg payloads into the stratosphere for periods of several weeks. The Infrared Montgolfiere is a hot air balloon that captures infrared radiation using the earth as a heat source. Thirty flights have been launched so far, some lasting more than sixty days and circling the globe twice.

  9. Introduction (Special Issue on Scientific Balloon Capabilities and Instrumentation)

    Science.gov (United States)

    Gaskin, Jessica A.; Smith, I. S.; Jones, W. V.

    2014-01-01

    In 1783, the Montgolfier brothers ushered in a new era of transportation and exploration when they used hot air to drive an un-tethered balloon to an altitude of 2 km. Made of sackcloth and held together with cords, this balloon challenged the way we thought about human travel, and it has since evolved into a robust platform for performing novel science and testing new technologies. Today, high-altitude balloons regularly reach altitudes of 40 km, and they can support payloads that weigh more than 3,000 kg. Long-duration balloons can currently support mission durations lasting 55 days, and developing balloon technologies (i.e. Super-Pressure Balloons) are expected to extend that duration to 100 days or longer; competing with satellite payloads. This relatively inexpensive platform supports a broad range of science payloads, spanning multiple disciplines (astrophysics, heliophysics, planetary and earth science.) Applications extending beyond traditional science include testing new technologies for eventual space-based application and stratospheric airships for planetary applications.

  10. Physisorption kinetics

    CERN Document Server

    Kreuzer, Hans Jürgen

    1986-01-01

    This monograph deals with the kinetics of adsorption and desorption of molecules physisorbed on solid surfaces. Although frequent and detailed reference is made to experiment, it is mainly concerned with the theory of the subject. In this, we have attempted to present a unified picture based on the master equation approach. Physisorption kinetics is by no means a closed and mature subject; rather, in writing this monograph we intended to survey a field very much in flux, to assess its achievements so far, and to give a reasonable basis from which further developments can take off. For this reason we have included many papers in the bibliography that are not referred to in the text but are of relevance to physisorption. To keep this monograph to a reasonable size, and also to allow for some unity in the presentation of the material, we had to omit a number of topics related to physisorption kinetics. We have not covered to any extent the equilibrium properties of physisorbed layers such as structures, phase tr...

  11. Catching Comet's Particles in the Earth's Atmosphere by Using Balloons

    Science.gov (United States)

    Potashko, Oleksandr; Viso, Michel

    The project is intended to catch cometary particles in the atmosphere by using balloons. The investigation is based upon knowledge that the Earth crosses the comet’s tails during the year. One can catch these particles at different altitudes in the atmosphere. So, we will be able to gradually advance in the ability to launch balloons from low to high altitudes and try to catch particles from different comet tails. The maximum altitude that we have to reach is 40 km. Both methods - distance observation and cometary samples from mission Stardust testify to the presence of organic components in comet’s particles. It would be useful to know more details about this organic matter for astrobiology; besides, the factor poses danger to the Earth. Moreover, it is important to prove that it is possible to get fundamental scientific results at low cost. In the last 5 years launching balloons has become popular and this movement looks like hackers’ one - as most of them occur without launch permission to airspace. The popularity of ballooning is connected with low cost of balloon, GPS unit, video recording unit. If you use iPhone, you have a light solution with GPS, video, picture and control function in one unit. The price of balloon itself begins from $50; it depends on maximum altitude, payload weight and material. Many university teams realized balloon launching and reached even stratosphere at an altitude of 33 km. But most of them take only video and picture. Meanwhile, it is possible to carry out scientific experiments by ballooning, for example to collect comet particles. There is rich experience at the moment of the use of mineral, chemical and isotopic analysis techniques and data of the comet’s dust after successful landing of StarDust capsule with samples in 2006. Besides, we may use absolutely perfect material to catch particles in the atmosphere, which was used by cosmic missions such as Stardust and Japanese Hayabusa. As to balloon launches, we could use

  12. Stability of n = 1 kink modes in bean-shaped tokamaks

    International Nuclear Information System (INIS)

    Manickam, J.; Grimm, R.C.; Okabayashi, M.

    1983-08-01

    Numerical studies show that by indenting the small-major-radius side of conventional finite-aspect-ratio tokamaks, significant improvements to the stability of pressure-driven ideal MHD modes can be achieved. The internal n - 1 kink mode can be stabilized completely with quite modest indentation. Kink-ballooning mode stability is also improved, and, in the presence of a nearby conducting wall, accessibility to a second stable region at high plasma β is possible

  13. Percutaneous balloon valvuloplasty in mitral stenosis

    International Nuclear Information System (INIS)

    Park, Jae Hyung; Oh, Byung Hee; Park, Kyung Ju; Kim, Seung Hyup; Lee, Young Woo; Han, Man Chung

    1989-01-01

    Percutaneous balloon valvuloplasty(PBV) was successfully performed in 8 mitral stenosis patients for recent 3 months. Five patients have aortic insufficiencies also and two patients have mitral regurgitations below grade II/IV. All patients showed sinus rhythm on EKG, and had no mitral valvular calcification on echocardiography and fluoroscopy. PBV resulted in an increase in mitral valve area from 1.22±0.22 to 2.57±0.86 cm 2 , a decrease in mean left atrial pressure from 23.4±9.6 to 7.5±3.4 mmHg and a decrease in mean mitral pressure gradient from 21.3±9.4 to 6.8±3.1 mmHg. There were no significant complications except 2 cases of newly appeared and mildly aggravated mitral regurgitation. We believe that PBV will become a treatment modality of choice replacing surgical commissurotomy or valve replacement in a group of mitral stenosis patients, because of its effectiveness and safety

  14. Mechanism of prostatic urethroplasty with balloon catheter

    International Nuclear Information System (INIS)

    Castaneda, F.; Maynar, M.; Hulbert, J.

    1988-01-01

    A series of 60 patients have undergone prostatic urethroplasty with balloon catheters at our institution. The follow-up of these patients has ranged from more than 3 years to not less than 6 months. The preliminary results have been excellent, with a success rate of 75% in patients with predominant lateral lobe hypertrophy. This success rate drops to 25% in patients with predominant middle lobe hypertrophy. In previous communications the authors have proposed that the mechanism of prostatic urethral relief of obstruction is due to stretching of the prostatic capsule, tissue compression, and possible subsequent atrophy, as suggested by findings of transrectal US, MR imaging, voiding and retrograde urethrography, and urinary flow studies. Recent clinical information that has led to further animal research has shown that in addition to the previously supposed mechanism of action, separation of the prostatic lobes occurs by splitting of the anterior and posterior commissures of the prostatic gland tissue. This separation of the prostatic lobes is therefore the goal of the procedure. As more experience is gained, the already high success rate can probably be improved

  15. Balloon catheter dilatation of benign urethral strictures

    International Nuclear Information System (INIS)

    Perini, L.; Cavallo, A.; Perin, B.; Bighi, G.

    1988-01-01

    The authors report their experience of benign urethral stricture dilatation by balloon catheter in 11 male patients. Ten posterior and 2 anterior urethral strictures were treated; in 1 patients several narrowings coexisted at various levels. Etiology was inflammatory in 4 cases, iatrogen in 3, post-traumatic in 2, and equivocal in 2. The patients were studied both before and soon after dilatation by means of retrograde and voiding cystourethrogram and uroflowgraphy; the follow-up (2-14 months) was performed by urodynamic alone. In all cases, dilatation was followed by the restoration of urethral gauge, together with prompt functional improvement of urodynamic parameters. The latter result subsisted in time in 9 patients. In 2 cases recurrences were observed demonstrated at once by clinics and urodynamics. Both lesions were successfully re-treated. Neither early not late complication occurred. In spite of the limited material, the valuable results obtained, together with the absence of complications, the peculiar morphology of recurrences, and the chance of repeating it make the procedure advisable as a valid alternative to conventional techniques for these pathologies

  16. Burn Injury Arise From Flying Balloon Toys

    Directory of Open Access Journals (Sweden)

    Yalcin Kulahci

    2007-08-01

    Full Text Available Many of peoples are faced minor or major burn injuries in their life. Even the most widespread burn cause is flame injuries, too different burn cause pointed out in literature like Acetylen burns. The cases which imply in literature, mostly causes from explosion of high pressure acetylene tube, metal oxygene patch flame or carbide lamp using from cave explorers. An interesting acetylene burn cause in Turkey was publised by the authors. This cases was to come into being from flying toy balloons flame. 80 person was injured from flying toy ballons flame in a meeting in 2002. Although this potential risks of acetylene, helium have not any of some risk. But helium was provided from other countries and have more price. The injuries which caused from acetylene burns like 1st -2nd degree burns. Consequently that was known helium is more avaliable for using in toy sector, and never cause burn injuries like this. [TAF Prev Med Bull. 2007; 6(4: 291-296

  17. Retrograde prostatic urethroplasty with a balloon catheter

    International Nuclear Information System (INIS)

    Castaneda, F.; Reddy, P.; Hulbert, J.; Letourneau, J.G.; Hunter, D.W.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1987-01-01

    Twenty-five patients with prostatism and documented BPH who were candidates for transurethral resection of the prostate were dilated for 10 minutes with 25-mm urethroplasty balloons using a retrograde transurethral approach. The procedure was performed under local anesthesia using 2% viscous lidocaine on an outpatient basis. A mild discomfort was experienced by all patients with a moderate urgency sensation. Mild transient hematuria was present in all, which cleared in 4 to 6 hours. Dysuria usually lasted for 72 hours. Significant improvement has been seen in the relief of symptoms in patients without middle-lobe hypertrophy as documented by uroflow studies, voiding cystourethrograms, and retrograde urethrograms. In patients with middle-lobe hypertrophy, moderate improvement in uroflow studies was observed, which correlated well with symptomatic improvement. Rectal US and MR studies have shown no evidence of intraprostatic or periprostatic abnormalities. No complications have been encountered so far. The longest current follow-up is 20 months, with a mean of 10 months

  18. First results of balloon dacryoplasty in dacryostenosis

    Directory of Open Access Journals (Sweden)

    Evgeniya L’vovna At’kova

    2015-06-01

    Full Text Available Background. Outpatient care is not widely spread in modern dacryology. At the same time, its necessity increases. There are no evidences of balloon dacryoplasty (BDP application in Russian periodical literature. Material and methods. 50 surgical procedures in 30 patients with partial nasolacrimal duct obliteration were performed, among them 30 BDP without lacrimal pathways intubation (group 1 and 20 with bicanalicular Ritleng intubation of lacrimal pathways (group 2. Lacrimal scintigraphy, single photon emission computed tomography, combined with X-ray computed tomography, subjective tearing estimation in points, and health depending quality of life evaluation wre performed in all cases. Same tests were repeated in 3 months after surgery. Results. A positive outcome rate was 90 % in both groups. There were no complications in group 1. A single case of stent dislocation was recorded in group 2. Conclusion. BDP is an effective procedure in dacryostenosis of the lacrimal pathways vertical part obliteration. This procedure helps to avoid complications associated with long stent retention. It is possible to get good functional results even at short term after BDP surgery, and there is a possibility for this procedure to be carried out in an outpatient setting.

  19. Plasma Modes

    Science.gov (United States)

    Dubin, D. H. E.

    This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.

  20. Hemispherical breathing mode speaker using a dielectric elastomer actuator.

    Science.gov (United States)

    Hosoya, Naoki; Baba, Shun; Maeda, Shingo

    2015-10-01

    Although indoor acoustic characteristics should ideally be assessed by measuring the reverberation time using a point sound source, a regular polyhedron loudspeaker, which has multiple loudspeakers on a chassis, is typically used. However, such a configuration is not a point sound source if the size of the loudspeaker is large relative to the target sound field. This study investigates a small lightweight loudspeaker using a dielectric elastomer actuator vibrating in the breathing mode (the pulsating mode such as the expansion and contraction of a balloon). Acoustic testing with regard to repeatability, sound pressure, vibration mode profiles, and acoustic radiation patterns indicate that dielectric elastomer loudspeakers may be feasible.

  1. Linear local stability of electrostatic drift modes in helical systems

    International Nuclear Information System (INIS)

    Yamagishi, O.; Nakajima, N.; Sugama, H.; Nakamura, Y.

    2003-01-01

    We investigate the stability of the drift wave in helical systems. For this purpose, we solve the linear local gyrokinetic-Poisson equation, in the electrostatic regime. As a model of helical plasmas, Large helical Device (LHD) is considered. The equation we apply is rather exact in the framework of linear gyrokinetic theory, where only the approximation is the ballooning representation. In this paper, we consider only collisionless cases. All the frequency regime can be naturally reated without any assumptions, and in such cases, ion temperature gradient modes (ITG), trapped electron modes (TEM), and electron temperature gradient modes (ETG) are expected to become unstable linearly independently. (orig.)

  2. Nonlinear magnetohydrodynamics of edge localized mode precursors

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. B., E-mail: guozhipku@gmail.com [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing (China); WCI Center for Fusion Theory, NFRI, Gwahangno 113, Yusung-gu, Daejeon 305-333 (Korea, Republic of); Wang, Lu [SEEE, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Wang, X. G. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing (China)

    2015-02-15

    A possible origin of edge-localized-mode (ELM) precursors based on nonlinear ideal peeling-ballooning mode is reported. Via nonlinear variational principle, a nonlinear evolution equation of the radial displacement is derived and solved, analytically. Besides an explosive growth in the initial nonlinear phase, it is found that the local displacement evolves into an oscillating state in the developed nonlinear phase. The nonlinear frequency of the ELM precursors scales as ω{sub pre}∼x{sup 1/3}ξ{sup ^}{sub ψ,in}{sup 2/3}n, with x position in radial direction, ξ{sup ^}{sub ψ,in} strength of initial perturbation, and n toroidal mode number.

  3. A model for asymmetric ballooning and analyses of ballooning behaviour of single rods with probabilistic methods

    International Nuclear Information System (INIS)

    Keusenhoff, J.G.; Schubert, J.D.; Chakraborty, A.K.

    1985-01-01

    Plastic deformation behaviour of Zircaloy cladding has been extensively examined in the past and can be described best by a model for asymmetric deformation. Slight displacement between the pellet and cladding will always exist and this will lead to the formation of azimuthal temperature differences. The ballooning process is strongly temperature dependent and, as a result of the built up temperature differences, differing deformation behaviours along the circumference of the cladding result. The calculated ballooning of cladding is mainly influenced by its temperature, the applied burst criterion and the parameters used in the deformation model. All these influencing parameters possess uncertainties. In order to quantify these uncertainties and to estimate distribution functions of important parameters such as temperature and deformation the response surface method was applied. For a hot rod the calculated standard deviation of cladding temperature amounts to 50 K. From this high value the large influence of the external cooling conditions on the deformation and burst behaviour of cladding can be estimated. In an additional statistical examination the parameters of deformation and burst models have been included and their influence on the deformation of the rod has been studied. (author)

  4. Balloon dacryocystoplasty: Incomplete versus complete obstruction of the nasolacrimal system

    International Nuclear Information System (INIS)

    Lee, Jeong Min; Lee, Sang Hoon; Han, Young Min; Chung, Gyung Ho; Kim, Chong Soo; Choi, Ki Chul; Song, Ho Young

    1993-01-01

    Balloon dilatation of nasolacrimal drainage apparatus was attempted for the treatment of stenoses or obstructures of the nasolacrimal system in 49 eyes of 41 consecutive patients with complete obstructions and 16 eyes of 14 patients with incomplete obstructions. These two groups were compared with regards to the effectiveness of balloon dacryocystoplasty. All patients suffered from severe epiphora had already undergone multiple probings. A 0.018 inch hair or ball guide wire was introduced through the superior punctum into the inferior meatus of the nasal cavity and pulled out through the nasal aperture using a hemostat under nasal endoscopy. A deflated angiography balloon catheter was then introduced in a retrograde direction and dilated under fluoroscopic control. No major complications occurred in any of the patients. At 7 days after balloon dilatation, 25 of 49 eyes with complete obstruction demonstrated improvement in epiphora (initial success rate: 51.0%) and among them 17 eyes showed complete resolution of symptoms. Reocclusion occurred in 12 of the 25 eyes with initial improvement at the 2 months follow up. For the 16 eyes with incomplete obstruction, and improvement of epiphora was attained in 11 eyes (initial success rate 68.8%): 5 of these eyes showed complete resolution of epiphora, and 3 was failed to maintain initial improvement at the 2 month follow up. Although this study demonstrate that results of balloon dacryocystoplasty are not encouraging because of the high failure and recurrence rate, balloon dacryocystoplasty is a simple and safe nonsurgical technique that can be used to treat for obstructions of the nasolacrimal system. In addition, balloon dacryocystoplasty shows better results in incomplete obstruction than in complete obstruction than complete obstruction of the nasolacrimal system

  5. Gastric emptying and intragastric balloon in obese patients.

    Science.gov (United States)

    Bonazzi, P; Petrelli, M D; Lorenzini, I; Peruzzi, E; Nicolai, A; Galeazzi, R

    2005-01-01

    Intragastric balloons have been proposed to induce weight loss in obese subjects. The consequences of the balloon on gastric physiology remain poorly studied. We studied the influence of an intragastric balloon on gastric emptying in obese patients. 12 patients were included in the study, with BMI (mean +/- SD) of 38.51 +/- 4.32 kg/m2. The balloon was inserted under light anaesthesia and endoscopic control, inflated with 700 ml saline, and removed 6 months later. Body weight and gastric emptying (T1/2 and T lag) using 13C-octanoic acid breath test were monitored before balloon placement, during its permanence and 2 months after removal. Mean weight loss was: 6.2 +/- 2.3 kg after one month; 12.4 +/- 5.8 kg after 3 months; 14.4 +/- 6.6 kg after 6 months and 10.1 +/- 4.3 kg two months after BIB removal. Gastric emptying rates were significantly decreased in the first periods with balloon in place, and returned to pre-implantation values after balloon removal. T1/2 was: 87 +/- 32 min before BIB positioning, 181 +/- 91 min after 1 month, 145 +/- 99 min after 3 months, 104 +/- 50 min after 6 months and 90 +/- 43 min 2 months after removal. T lag was 36 +/- 18 min before BIB positioning, 102 +/- 82 min after 1 month, 77 +/- 53 min after 3 months, 59 +/- 28 min after 6 months and 40 +/- 21 min. 2 months after removal. BIB in obese patients seems to be a good help in following the hypo caloric diet, especially during the first three months when the gastric emptying is slower and the sense of repletion is higher. After this period gastric emptying starts to return to normal and the stomach adapts to BIB loosing efficacy in weight loss.

  6. Scientific ballooning. Proceedings. PSB Meeting of the COSPAR Panel on Technical Problems Related to Scientific Ballooning which was held during the Thirtieth COSPAR Scientific Assembly, Hamburg (Germany), 11 - 21 Jul 1994.

    Science.gov (United States)

    Riedler, W.; Torkar, K.

    1996-05-01

    This issue is grouped into sections on materials, design, performance and analysis of balloons, reviews of major national and international balloon programmes, novel instrumentation and systems for scientific ballooning, and selected recent scientific observations.

  7. Stochastic kinetics

    International Nuclear Information System (INIS)

    Colombino, A.; Mosiello, R.; Norelli, F.; Jorio, V.M.; Pacilio, N.

    1975-01-01

    A nuclear system kinetics is formulated according to a stochastic approach. The detailed probability balance equations are written for the probability of finding the mixed population of neutrons and detected neutrons, i.e. detectrons, at a given level for a given instant of time. Equations are integrated in search of a probability profile: a series of cases is analyzed through a progressive criterium. It tends to take into account an increasing number of physical processes within the chosen model. The most important contribution is that solutions interpret analytically experimental conditions of equilibrium (moise analysis) and non equilibrium (pulsed neutron measurements, source drop technique, start up procedures)

  8. Developments of Highly Multiplexed, Multi-chroic Pixels for Balloon-Borne Platforms

    Science.gov (United States)

    Aubin, F.; Hanany, S.; Johnson, B. R.; Lee, A.; Suzuki, A.; Westbrook, B.; Young, K.

    2018-02-01

    We present our work to develop and characterize low thermal conductance bolometers that are part of sinuous antenna multi-chroic pixels (SAMP). We use longer, thinner and meandered bolometer legs to achieve 9 pW/K thermal conductance bolometers. We also discuss the development of inductor-capacitor chips operated at 4 K to extend the multiplexing factor of the frequency domain multiplexing to 105, an increase of 60% compared to the factor currently demonstrated for this readout system. This technology development is motivated by EBEX-IDS, a balloon-borne polarimeter designed to characterize the polarization of foregrounds and to detect the primordial gravity waves through their B-mode signature on the polarization of the cosmic microwave background. EBEX-IDS will operate 20,562 transition edge sensor bolometers spread over 7 frequency bands between 150 and 360 GHz. Balloon and satellite platforms enable observations at frequencies inaccessible from the ground and with higher instantaneous sensitivity. This development improves the readiness of the SAMP and frequency domain readout technologies for future satellite applications.

  9. Tolrestat kinetics

    International Nuclear Information System (INIS)

    Hicks, D.R.; Kraml, M.; Cayen, M.N.; Dubuc, J.; Ryder, S.; Dvornik, D.

    1984-01-01

    The kinetics of tolrestat, a potent inhibitor of aldose reductase, were examined. Serum concentrations of tolrestat and of total 14 C were measured after dosing normal subjects and subjects with diabetes with 14 C-labeled tolrestat. In normal subjects, tolrestat was rapidly absorbed and disappearance from serum was biphasic. Distribution and elimination t 1/2s were approximately 2 and 10 to 12 hr, respectively, after single and multiple doses. Unchanged tolrestat accounted for the major portion of 14 C in serum. Radioactivity was rapidly and completely excreted in urine and feces in an approximate ratio of 2:1. Findings were much the same in subjects with diabetes. In normal subjects, the kinetics of oral tolrestat were independent of dose in the 10 to 800 mg range. Repetitive dosing did not result in unexpected cumulation. Tolrestat was more than 99% bound to serum protein; it did not compete with warfarin for binding sites but was displaced to some extent by high concentrations of tolbutamide or salicylate

  10. Three-dimensional linear peeling-ballooning theory in magnetic fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Weyens, T., E-mail: tweyens@fis.uc3m.es; Sánchez, R.; García, L. [Departamento de Física, Universidad Carlos III de Madrid, Madrid 28911 (Spain); Loarte, A.; Huijsmans, G. [ITER Organization, Route de Vinon sur Verdon, 13067 Saint Paul Lez Durance (France)

    2014-04-15

    Ideal magnetohydrodynamics theory is extended to fully 3D magnetic configurations to investigate the linear stability of intermediate to high n peeling-ballooning modes, with n the toroidal mode number. These are thought to be important for the behavior of edge localized modes and for the limit of the size of the pedestal that governs the high confinement H-mode. The end point of the derivation is a set of coupled second order ordinary differential equations with appropriate boundary conditions that minimize the perturbed energy and that can be solved to find the growth rate of the perturbations. This theory allows of the evaluation of 3D effects on edge plasma stability in tokamaks such as those associated with the toroidal ripple due to the finite number of toroidal field coils, the application of external 3D fields for elm control, local modification of the magnetic field in the vicinity of ferromagnetic components such as the test blanket modules in ITER, etc.

  11. Intrarectal pressures and balloon expulsion related to evacuation proctography.

    Science.gov (United States)

    Halligan, S; Thomas, J; Bartram, C

    1995-01-01

    Seventy four patients with constipation were examined by standard evacuation proctography and then attempted to expel a small, non-deformable rectal balloon, connected to a pressure transducer to measure intrarectal pressure. Simultaneous imaging related the intrarectal position of the balloon to rectal deformity. Inability to expel the balloon was associated proctographically with prolonged evacuation, incomplete evacuation, reduced anal canal diameter, and acute anorectal angulation during evacuation. The presence and size of rectocoele or intussusception was unrelated to voiding of paste or balloon. An independent linear combination of pelvic floor descent and evacuation time on proctography correctly predicted maximum intrarectal pressure in 74% of cases. No patient with both prolonged evacuation and reduced pelvic floor descent on proctography could void the balloon, as maximum intrarectal pressure was reduced in this group. A prolonged evacuation time on proctography, in combination with reduced pelvic floor descent, suggests defecatory disorder may be caused by inability to raise intrarectal pressure. A diagnosis of anismus should not be made on proctography solely on the basis of incomplete/prolonged evacuation, as this may simply reflect inadequate straining. PMID:7672656

  12. Aerial Deployment and Inflation System for Mars Helium Balloons

    Science.gov (United States)

    Lachenmeler, Tim; Fairbrother, Debora; Shreves, Chris; Hall, Jeffery, L.; Kerzhanovich, Viktor V.; Pauken, Michael T.; Walsh, Gerald J.; White, Christopher V.

    2009-01-01

    A method is examined for safely deploying and inflating helium balloons for missions at Mars. The key for making it possible to deploy balloons that are light enough to be buoyant in the thin, Martian atmosphere is to mitigate the transient forces on the balloon that might tear it. A fully inflated Mars balloon has a diameter of 10 m, so it must be folded up for the trip to Mars, unfolded upon arrival, and then inflated with helium gas in the atmosphere. Safe entry into the Martian atmosphere requires the use of an aeroshell vehicle, which protects against severe heating and pressure loads associated with the hypersonic entry flight. Drag decelerates the aeroshell to supersonic speeds, then two parachutes deploy to slow the vehicle down to the needed safe speed of 25 to 35 m/s for balloon deployment. The parachute system descent dynamic pressure must be approximately 5 Pa or lower at an altitude of 4 km or more above the surface.

  13. Time-dependent strains and stresses in a pumpkin balloon

    Science.gov (United States)

    Gerngross, T.; Xu, Y.; Pellegrino, S.

    This paper presents a study of pumpkin-shaped superpressure balloons consisting of gores made from a thin polymeric film attached to high stiffness meridional tendons This type of design is being used for the NASA ULDB balloons The gore film shows considerable time-dependent stress relaxation whereas the behaviour of the tendons is essentially time-independent Upon inflation and pressurization the instantaneous i e linear-elastic strain and stress distributions in the film show significantly higher values in the meridional direction However over time and due to the biaxial visco-elastic stress relaxation of the the gore material the em hoop strains increase and the em meridional stresses decrease whereas the em remaining strain and stress components remain substantially unchanged These results are important for a correct assessment of the structural integrity of a pumpkin balloon in a long-duration mission both in terms of the material performance and the overall stability of the shape of the balloon An experimental investigation of the time dependence of the biaxial strain distribution in the film of a 4 m diameter 48 gore pumpkin balloon is presented The inflated shape of selected gores has been measured using photogrammetry and the time variation in strain components at some particular points of these gores has been measured under constant pressure and temperature The results show good correlation with a numerical study using the ABAQUS finite-element package that includes a widely used model of

  14. Cryo-balloon catheter localization in fluoroscopic images

    Science.gov (United States)

    Kurzendorfer, Tanja; Brost, Alexander; Jakob, Carolin; Mewes, Philip W.; Bourier, Felix; Koch, Martin; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2013-03-01

    Minimally invasive catheter ablation has become the preferred treatment option for atrial fibrillation. Although the standard ablation procedure involves ablation points set by radio-frequency catheters, cryo-balloon catheters have even been reported to be more advantageous in certain cases. As electro-anatomical mapping systems do not support cryo-balloon ablation procedures, X-ray guidance is needed. However, current methods to provide support for cryo-balloon catheters in fluoroscopically guided ablation procedures rely heavily on manual user interaction. To improve this, we propose a first method for automatic cryo-balloon catheter localization in fluoroscopic images based on a blob detection algorithm. Our method is evaluated on 24 clinical images from 17 patients. The method successfully detected the cryoballoon in 22 out of 24 images, yielding a success rate of 91.6 %. The successful localization achieved an accuracy of 1.00 mm +/- 0.44 mm. Even though our methods currently fails in 8.4 % of the images available, it still offers a significant improvement over manual methods. Furthermore, detecting a landmark point along the cryo-balloon catheter can be a very important step for additional post-processing operations.

  15. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a ω is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, Q/sub xy/, whenever a coherent dipole oscillation exists

  16. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a(ω) is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, whenever a coherent dipole oscillation exists

  17. Viscose kink and drift-kink modes in a tokamak

    International Nuclear Information System (INIS)

    Kuvshinov, B.N.; Mikhajlovskij, A.B.

    1988-01-01

    Intristic kink modes in a tokamak are theoretically investigated taking account of longitudinal viscosity of ions and electrons and drift effect. It is marked that dispersion equation of investigated modes coinsides in form with that for ballooning modes. It is shown that five types of intrinsic kink instability may be distinguished in disregard of viscosity and drift effects. Effect of stabilizing quasiideal viscose kink and viscose resistive kink modes by finite Larmuir ion radius is investigated. A branch of viscose reclosure mode which instability is due to electron viscosity is pointed out. A series of other viscose and drift-kink tokamak modes is considered. Both general disperse equations of the above-mentioned kink instability varieties, taking account of viscose and drift ones, and disperse equations of separate branches are presented

  18. Original monitoring of desert dust in African air masses transported over the Mediterranean Sea by quasi-Lagrangian drifting balloons and sounding balloons during the summer 2013 ChArMEx field campaign

    Science.gov (United States)

    Dulac, F.; Renard, J. B.; Durand, P.; Denjean, C.; Bourgeois, Q.; Vignelles, D.; Jeannot, M.; Mallet, M.; Verdier, N.

    2017-12-01

    This study focuses on in situ balloon-borne measurements of mineral dust from summer regional field campaigns in the western Mediterranean basin performed in the framework of ChArMEx (the Chemistry and Aerosol Mediterranean Experiment; see special issue https://www.atmos-chem-phys.net/special_issue334.html). Due to long-range transport from Africa, the lower troposphere over this regional sea is subject to high levels of desert dust with a maximum during the long dry and sunny Mediterranean summer season. Based on developments of boundary-layer pressurized balloons (BLPBs) and of a dedicated optical particle counter named LOAC (Light Optical Aerosol Counter/sizer), we were able to perform original quasi-Lagrangian monitoring of desert dust aerosols over the sea. The strategy combined classical sounding balloons and drifting BLPBs to document both the vertical distribution and long-range transport. A total of 27 LOAC flights were successfully conducted from Minorca Isl. (Spain) or Levant Isl. (France), during 4 Saharan dust transport events, including 10 flights with BLPBs at drifting altitudes between 2.0 and 3.3 km above sea level. The longest flight exceeded 700 km and lasted more than 25 h. Numerous tests and validations of LOAC measurements were performed to qualify the instrument, including comparisons with concurrent airborne measurements, sounding balloons, and remote sensing measurements with an AERONET sun-photometer, and a ground-based and the CALIOP lidar systems. Aerosol optical depths in the balloon vicinity did not exceed about 0.4 but the presence of turbid dust layers was confirmed thanks to dual scattering angle measurements by LOAC allowing the identification of dust particles. LOAC data could generally be fitted by a 3-mode lognormal distribution at roughly 0.2, 4 and 30 µm in modal diameter. Up to about 10-4 dust particles larger than 40 µm per cm3 are reported and no significant evolution of the size distribution was observed during the

  19. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained s...

  20. Review of the British scientific sounding rocket and balloon programmes

    International Nuclear Information System (INIS)

    Delury, J.T.

    1978-01-01

    This review describes the UK scientific sounding rocket programmes which have utilised Skylarks for 21 years, Petrels for 10 years and Fulmars for 2 years. The SRC's ongoing programme is now based on the Petrel and Fulmar rockets, and approved proposals by 5 UK scientific groups covering 1978 and 1979 are outlined. The British scientific balloon programme, which serves 14 scientific groups within UK universities, involves a planned 10 flights per annum using balloons of 3 M cu ft to 31 M cu ft capacity and payloads up to 2 tons in weight. The review outlines the balloon programme of flights planned mainly from Palestine in Texas and Alice Springs/Mildura in Australia. (author)

  1. [Valvuloplasty with balloon catheter in biologic prosthesis. Reality or illusion].

    Science.gov (United States)

    Ledesma Velasco, M; Verdín Vázquez, R; Acosta Valdez, J L; Munayer Calderón, J; Salgado Escobar, J L; Arias Monroy, L; Flores Mendoza, J

    1989-01-01

    We performed catheter balloon valvuloplasty (CBV) on 8 stenotic operatively-excised bioprosthetic valves (2 Hancock and 6 Ionescu Shiley). Pathology of valves before CBV included degenerative changes: commissural fusion by mounds of calcific deposits (2 valves), fibrotic and focally calcified leaflets (7 valves) and stiff and thick valves (1 valve). Inflation of the balloon resulted in commissural splitting (2 valves), leaflet cracks and fractures (3 valves). Removal of the deflated balloon catheter was associated with debris dislodgement (3 valves). In one case the valve was unable to close with potential for acute regurgitation. Thus, CBV of bioprosthetic valves can split fused commissures by similar mechanisms as in native valves. CBV may fracture calcific deposits causing acute emboli. It can also disrupt the leaflets causing acute insufficiency. The findings suggest a limited role of CBV in the treatment of stenotic bioprosthetic valves in mitral and aortic position.

  2. Ileal Varices Treated with Balloon-Occluded Retrograde Transvenous Obliteration.

    Science.gov (United States)

    Sato, Takahiro; Yamazaki, Katsu; Toyota, Jouji; Karino, Yoshiyasu; Ohmura, Takumi; Akaike, Jun

    2009-04-01

    A 55-year-old man with hepatitis B virus antigen-positive liver cirrhosis was admitted to our hospital with anal bleeding. Colonoscopy revealed blood retention in the entire colon, but no bleeding lesion was found. Computed tomography images showed that vessels in the ileum were connected to the right testicular vein, and we suspected ileal varices to be the most probable cause of bleeding. We immediately performed double balloon enteroscopy, but failed to find any site of bleeding owing to the difficulty of fiberscope insertion with sever adhesion. Using a balloon catheter during retrograde transvenous venography, we found ileal varices communicating with the right testicular vein (efferent vein) with the superior mesenteric vein branch as the afferent vein of these varices. We performed balloon occluded retrograde transvenous obliteration by way of the efferent vein of the varices and have detected no further bleeding in this patient one year after treatment.

  3. JUBA (Joint UAS-Balloon Activities) Final Campaign Report.

    Energy Technology Data Exchange (ETDEWEB)

    Dexheimer, Darielle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Apple, Monty [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Callow, Diane Schafer [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Longbottom, Casey Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Novick, David K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wilson, Christopher W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    Using internal investment funds within Sandia National Laboratories’ (SNL) Division 6000, JUBA was a collaborative exercise between SNL Orgs. 6533 & 6913 (later 8863) to demonstrate simultaneous flights of tethered balloons and UAS on the North Slope of Alaska. JUBA UAS and tethered balloon flights were conducted within the Restricted Airspace associated with the ARM AMF3 site at Oliktok Point, Alaska. The Restricted Airspace occupies a 2 nautical mile radius around Oliktok Point. JUBA was conducted at the Sandia Arctic Site, which is approximately 2 km east-southeast of the AMF3. JUBA activities occurred from 08/08/17 – 08/10/17. Atmospheric measurements from tethered balloons can occur for a long duration, but offer limited spatial variation. Measurements from UAS could offer increased spatial variability.

  4. Iridium: Global OTH data communications for high altitude scientific ballooning

    Science.gov (United States)

    Denney, A.

    While the scientific community is no stranger to embracing commercially available technologies, the growth and availability of truly affordable cutting edge technologies is opening the door to an entirely new means of global communications. For many years high altitude ballooning has provided science an alternative to costly satellite based experimental platforms. As with any project, evolution becomes an integral part of development. Specifically in the NSBF ballooning program, where flight durations have evolved from the earlier days of hours to several weeks and plans are underway to provide missions up to 100 days. Addressing increased flight durations, the harsh operational environment, along with cumbersome and outdated systems used on existing systems, such as the balloon vehicles Support Instrumentation Package (SIP) and ground-based systems, a new Over-The-Horizon (OTH) communications medium is sought. Current OTH equipment planning to be phased-out include: HF commanding systems, ARGOS PTT telemetry downlinks and INMARSAT data terminals. Other aspects up for review in addition to the SIP to utilize this communications medium include pathfinder balloon platforms - thereby, adding commanding abilities and increased data rates, plus providing a package for ultra-small experiments to ride aloft. Existing communication systems employed by the National Scientific Balloon Facility ballooning program have been limited not only by increased cost, slow data rates and "special government use only" services such as TDRSS (Tracking and Data Relay Satellite System), but have had to make special provisions to geographical flight location. Development of the Support Instrumentation Packages whether LDB (Long Duration Balloon), ULDB (Ultra Long Duration Balloon) or conventional ballooning have been plagued by non-standard systems configurations requiring additional support equipment for different regions and missions along with a myriad of backup for redundancy. Several

  5. Balloon dilatation for the treatment of stricture of gastrojejunostomy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yeon Hwa [Lee Rha Hospital, Chungju (Korea, Republic of); Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Han, Young Min; Chon, Su Bin; Chung, Gyung Ho; Kim, Chong Soo; Choi, Ki Chul [Chonbuk National University College of Medicine, Chungju (Korea, Republic of)

    1993-07-15

    Enteroenteric anastomotic strictures of UGI tract are common and require treatment if significant obstruction occurs. We performed fluoroscopic guided balloon dilatation in 6 patients who had symptomatic stricture of gastrojejunostomy. The stricture was successfully resolved in 4 patients with benign stricture. But 2 patients with malignant stricture had recurrence of obstructive symptoms 2 weeks later, and they required a stent. Asymptomatic balloon rupture was seen in one patients, but other procedural complications did not occur. We found that fluoroscopic guided balloon dilatation is an effective and safe method in the treatment of anastomotic stricture of gastrojejunostomy. We also found transient effect in malignant gastrojejunal anastomotic strictures, which required an interventional procedure, such as placement of a stent.

  6. Prognostic factors for the success of thermal balloon ablation in the treatment of menorrhagia

    NARCIS (Netherlands)

    Bongers, M. Y.; Mol, B. W. J.; Brölmann, H. A. M.

    2002-01-01

    OBJECTIVE: To identify predictive factors that will ensure successful menorrhagia treatment using hot fluid balloon endometrial ablation. METHODS: This is a prospective study on patients referred for menorrhagia and treated with hot fluid thermal balloon ablation. Potential prognostic factors for

  7. Origin of non-spherical particles in the boundary layer over Beijing, China: based on balloon-borne observations.

    Science.gov (United States)

    Chen, Bin; Yamada, Maromu; Iwasaka, Yasunobu; Zhang, Daizhou; Wang, Hong; Wang, Zhenzhu; Lei, Hengchi; Shi, Guangyu

    2015-10-01

    Vertical structures of aerosols from the ground to about 1,000 m altitude in Beijing were measured with a balloon-borne optical particle counter. The results showed that, in hazy days, there were inversions at approximately 500-600 m, below which the particulate matters were well mixed vertically, while the concentration of particles decreased sharply above the mixing layer. Electron microscopic observation of the particles collected with the balloon-borne impactor indicates that the composition of particles is different according to weather conditions in the boundary mixing layer of Beijing city and suggests that dust particles are always dominant in coarse-mode particles. Interestingly, sea-salt particles are frequently identified, suggesting the importance of marine air inflow to the Beijing area even in summer. The Ca-rich spherical particles are also frequently identified, suggesting chemical modification of dust particle by NOx or emission of CaO and others from local emission. Additionally, those types of particles showed higher concentration above the mixing layer under the relatively calm weather condition of summer, suggesting the importance of local-scale convection found in summer which rapidly transported anthropogenic particles above the mixing layer. Lidar extinction profiles qualitatively have good consistency with the balloon-borne measurements. Attenuation effects of laser pulse intensity are frequently observed due to high concentration of particulate matter in the Beijing atmosphere, and therefore quantitative agreement of lidar return and aerosol concentration can be hardly observed during dusty condition. Comparing the depolarization ratio obtained from the lidar measurements with the balloon-borne measurements, the contribution of the dry sea-salt particles, in addition to the dust particles, is suggested as an important factor causing depolarization ratio in the Beijing atmosphere.

  8. Three dimensional nonlinear simulations of edge localized modes on the EAST tokamak using BOUT++ code

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z. X., E-mail: zxliu316@ipp.ac.cn; Xia, T. Y.; Liu, S. C.; Ding, S. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Xu, X. Q.; Joseph, I.; Meyer, W. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Gao, X.; Xu, G. S.; Shao, L. M.; Li, G. Q.; Li, J. G. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2014-09-15

    Experimental measurements of edge localized modes (ELMs) observed on the EAST experiment are compared to linear and nonlinear theoretical simulations of peeling-ballooning modes using the BOUT++ code. Simulations predict that the dominant toroidal mode number of the ELM instability becomes larger for lower current, which is consistent with the mode structure captured with visible light using an optical CCD camera. The poloidal mode number of the simulated pressure perturbation shows good agreement with the filamentary structure observed by the camera. The nonlinear simulation is also consistent with the experimentally measured energy loss during an ELM crash and with the radial speed of ELM effluxes measured using a gas puffing imaging diagnostic.

  9. The effect of plasma beta on high-n ballooning stability at low magnetic shear

    Science.gov (United States)

    Connor, J. W.; Ham, C. J.; Hastie, R. J.

    2016-08-01

    An explanation of the observed improvement in H-mode pedestal characteristics with increasing core plasma pressure or poloidal beta, {β\\text{pol}} , as observed in MAST and JET, is sought in terms of the impact of the Shafranov shift, {{Δ }\\prime} , on ideal ballooning MHD stability. To illustrate this succinctly, a self-consistent treatment of the low magnetic shear region of the ‘s-α ’ stability diagram is presented using the large aspect ratio Shafranov equilibrium, but enhancing both α and {{Δ }\\prime} so that they compete with each other. The method of averaging, valid at low s, is used to simplify the calculation and demonstrates how α , {{Δ }\\prime} , plasma shaping and ‘average favourable curvature’ all contribute to stability.

  10. A local network integrated into a balloon-borne apparatus

    Science.gov (United States)

    Imori, Masatosi; Ueda, Ikuo; Shimamura, Kotaro; Maeno, Tadashi; Murata, Takahiro; Sasaki, Makoto; Matsunaga, Hiroyuki; Matsumoto, Hiroshi; Shikaze, Yoshiaki; Anraku, Kazuaki; Matsui, Nagataka; Yamagami, Takamasa

    A local network is incorporated into an apparatus for a balloon-borne experiment. A balloon-borne system implemented in the apparatus is composed of subsystems interconnected through a local network, which introduces modular architecture into the system. The network decomposes the balloon-borne system into subsystems, which are similarly structured from the point of view that the systems is kept under the control of a ground station. The subsystem is functionally self-contained and electrically independent. A computer is integrated into a subsystem, keeping the subsystem under the control. An independent group of batteries, being dedicated to a subsystem, supplies the whole electricity of the subsystem. The subsystem could be turned on and off independently of the other subsystems. So communication among the subsystems needs to be based on such a protocol that could guarantee the independence of the individual subsystems. An Omninet protocol is employed to network the subsystems. A ground station sends commands to the balloon-borne system. The command is received and executed at the system, then results of the execution are returned to the ground station. Various commands are available so that the system borne on a balloon could be controlled and monitored remotely from the ground station. A subsystem responds to a specific group of commands. A command is received by a transceiver subsystem and then transferred through the network to the subsystem to which the command is addressed. Then the subsystem executes the command and returns results to the transceiver subsystem, where the results are telemetered to the ground station. The network enhances independence of the individual subsystems, which enables programs of the individual subsystems to be coded independently. Independence facilitates development and debugging of programs, improving the quality of the system borne on a balloon.

  11. Balloon-Borne Infrasound Detection of Energetic Bolide Events

    Science.gov (United States)

    Young, Eliot F.; Ballard, Courtney; Klein, Viliam; Bowman, Daniel; Boslough, Mark

    2016-10-01

    Infrasound is usually defined as sound waves below 20 Hz, the nominal limit of human hearing. Infrasound waves propagate over vast distances through the Earth's atmosphere: the CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization) has 48 installed infrasound-sensing stations around the world to detect nuclear detonations and other disturbances. In February 2013, several CTBTO infrasound stations detected infrasound signals from a large bolide that exploded over Chelyabinsk, Russia. Some stations recorded signals that had circumnavigated the Earth, over a day after the original event. The goal of this project is to improve upon the sensitivity of the CTBTO network by putting microphones on small, long-duration super-pressure balloons, with the overarching goal of studying the small end of the NEO population by using the Earth's atmosphere as a witness plate.A balloon-borne infrasound sensor is expected to have two advantages over ground-based stations: a lack of wind noise and a concentration of infrasound energy in the "stratospheric duct" between roughly 5 - 50 km altitude. To test these advantages, we have built a small balloon payload with five calibrated microphones. We plan to fly this payload on a NASA high-altitude balloon from Ft Sumner, NM in August 2016. We have arranged for three large explosions to take place in Socorro, NM while the balloon is aloft to assess the sensitivity of balloon-borne vs. ground-based infrasound sensors. We will report on the results from this test flight and the prospects for detecting/characterizing small bolides in the stratosphere.

  12. Second-generation endometrial ablation technologies: the hot liquid balloons.

    Science.gov (United States)

    Vilos, George A; Edris, Fawaz

    2007-12-01

    Hysteroscopic endometrial ablation (HEA) was introduced in the 1980s to treat menorrhagia. Its use required additional training, surgical expertise and specialized equipment to minimize emergent complications such as uterine perforations, thermal injuries and excessive fluid absorption. To overcome these difficulties and concerns, thermal balloon endometrial ablation (TBEA) was introduced in the 1990s. Four hot liquid balloons have been introduced into clinical practice. All systems consist of a catheter (4-10mm diameter), a silicone balloon and a control unit. Liquids used to inflate the balloons include internally heated dextrose in water (ThermaChoice, 87 degrees C), and externally heated glycine (Cavaterm, 78 degrees C), saline (Menotreat, 85 degrees ) and glycerine (Thermablate, 173 degrees C). All balloons require pressurization from 160 to 240 mmHg for treatment cycles of 2 to 10 minutes. Prior to TBEA, preoperative endometrial thinning, including suction curettage, is optional. Several RCTs and cohort studies indicate that the advantages of TBEA include portability, ease of use and short learning curve. In addition, small diameter catheters requiring minimal cervical dilatation (5-7 mm) and short duration of treatment cycles (2-8 min) allow treatment under minimal analgesia/anesthesia requirements in a clinic setting. Following TBEA serious adverse events, including thermal injuries to viscera have been experienced. To minimize such injuries some surgeons advocate the use of routine post-dilatation hysteroscopy and/or ultrasonography to confirm correct intrauterine placement of the balloon prior to initiating the treatment cycle. After 10 years of clinical practice, TBEA is thought to be the preferred first-line surgical treatment of menorrhagia in appropriately selected candidates. Economic modeling also suggested that TBEA may be more cost-effective than HEA.

  13. Blood pressure normalization post-jugular venous balloon angioplasty.

    Science.gov (United States)

    Sternberg, Zohara; Grewal, Prabhjot; Cen, Steven; DeBarge-Igoe, Frances; Yu, Jinhee; Arata, Michael

    2015-05-01

    This study is the first in a series investigating the relationship between autonomic nervous system dysfunction and chronic cerebrospinal venous insufficiency in multiple sclerosis patients. We screened patients for the combined presence of the narrowing of the internal jugular veins and symptoms of autonomic nervous system dysfunction (fatigue, cognitive dysfunction, sleeping disorders, headache, thermal intolerance, bowel/bladder dysfunction) and determined systolic and diastolic blood pressure responses to balloon angioplasty. The criteria for eligibility for balloon angioplasty intervention included ≥ 50% narrowing in one or both internal jugular veins, as determined by the magnetic resonance venography, and ≥ 3 clinical symptoms of autonomic nervous system dysfunction. Blood pressure was measured at baseline and post-balloon angioplasty. Among patients who were screened, 91% were identified as having internal jugular veins narrowing (with obstructing lesions) combined with the presence of three or more symptoms of autonomic nervous system dysfunction. Balloon angioplasty reduced the average systolic and diastolic blood pressure. However, blood pressure categorization showed a biphasic response to balloon angioplasty. The procedure increased blood pressure in multiple sclerosis patients who presented with baseline blood pressure within lower limits of normal ranges (systolic ≤ 105 mmHg, diastolic ≤ 70 mmHg) but decreased blood pressure in patients with baseline blood pressure above normal ranges (systolic ≥ 130 mmHg, diastolic ≥ 80 mmHg). In addition, gender differences in baseline blood pressure subcategories were observed. The coexistence of internal jugular veins narrowing and symptoms of autonomic nervous system dysfunction suggests that the two phenomena may be related. Balloon angioplasty corrects blood pressure deviation in multiple sclerosis patients undergoing internal jugular vein dilation. Further studies should investigate the

  14. Kinetics of coal pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M. (United Technologies Research Center, East Hartford, CT (USA)); Howard, J.B.; Peters, W.; Hsu, J.; Hajaligol, M.; Sarofim, A. (Massachusetts Inst. of Tech., Cambridge, MA (USA)); Jenkins, R.; Mallin, J.; Espindola-Merin, B. (Pennsylvania State Univ., University Park, PA (USA)); Essenhigh, R.; Misra, M.K. (Ohio State Univ., Columbus, OH (USA))

    1989-07-01

    This report contains results of a coordinated, multi-laboratory investigation of coal devolatilization. Data is reported pertaining to the devolatilization for bituminous coals over three orders of magnitude in apparent heating rate (100 to 100,000 + {degree}C/sec), over two orders of magnitude in particle size (20 to 700 microns), final particle temperatures from 400 to 1600{degree}C, heat transfer modes ranging from convection to radiative, ambient pressure ranging from near vacuum to one atmosphere pressure. The heat transfer characteristics of the reactors are reported in detail. It is assumed the experimental results are to form the basis of a devolatilization data base. Empirical rate expressions are developed for each phase of devolatilization which, when coupled to an awareness of the heat transfer rate potential of a particular devolatilization reactor, indicate the kinetics emphasized by a particular system reactor plus coal sample. The analysis indicates the particular phase of devolatilization that will be emphasized by a particular reactor type and, thereby, the kinetic expressions appropriate to that devolatilization system. Engineering rate expressions are developed from the empirical rate expressions in the context of a fundamental understanding of coal devolatilization developed in the course of the investigation. 164 refs., 223 figs., 44 tabs.

  15. Severe Sunburn After a Hot Air Balloon Ride: A Case Report and Literature Review.

    Science.gov (United States)

    Ozturk, Sinan; Karagoz, Huseyin

    2015-01-01

    Hot air balloon tours are very popular among travelers worldwide. Preventable burn injuries associated with hot air balloon rides have been reported during crashes into power lines, in propane burner explosions, and following contact with the propane burner tanks. We present a case of severe repeated sunburn, which poses another risk of preventable injury during hot air balloon rides, and briefly discuss the injury epidemiology of hot air balloon rides. © 2015 International Society of Travel Medicine.

  16. The German scientific balloon and sounding rocket projects

    International Nuclear Information System (INIS)

    Dalh, A.F.

    1978-01-01

    This report contains information on the sounding rocket projects: experiment preparation for spacelab (astronomy), aeronomy, magnetosphere, and material science. Except for material science the scientific balloon projects are performed in the some scientific fields, but with a strong emphasis on astronomical research. It is tried to provide by means of tables a survey as complete as possible of the projects for the time since the last symposium in Elmau and of the plans for the future until 1981. The scientific balloon and sounding rocket projects form a small succesful part of the German space research programme. (author)

  17. Ballooning Representation Approach to Low-Frequency Instabilities in Stellarators

    International Nuclear Information System (INIS)

    Dewar, R.L.; Gardner, H.J.; Lewandowski, J.; Persson, M.

    1995-01-01

    Local ideal MHD ballooning eigenvalues have been calculated on many field lines for heliac and torsatron cases using a parallel implementation of a ballooning code on a Thinking Machines Corporation CM-5 Global eigenvalues have been estimated for the torsatron test case using the ray tracing method of Dewar and Glasser and also by using the TERPSI-CHORE global eigenvalue code, with good agreement. As a preliminary to detailed study of H-1, 3-D visualizations of stability-related quantities have been produced. 6 refs

  18. The German scientific balloon and sounding rocket programme

    International Nuclear Information System (INIS)

    Dahl, A.F.

    1980-01-01

    This report contains information on sounding rocket projects in the scientific field of astronomy, aeronomy, magnetosphere, and material science under microgravity. The scientific balloon projects are performed with emphasis on astronomical research. By means of tables it is attempted to give a survey, as complete as possible, of the projects the time since the last symposium in Ajaccio, Corsica, and of preparations and plans for the future until 1983. The scientific balloon and sounding rocket projects form a small successful part of the German space research programme. (Auth.)

  19. Cloud Water Content Sensor for Sounding Balloons and Small UAVs

    Science.gov (United States)

    Bognar, John A.

    2009-01-01

    A lightweight, battery-powered sensor was developed for measuring cloud water content, which is the amount of liquid or solid water present in a cloud, generally expressed as grams of water per cubic meter. This sensor has near-zero power consumption and can be flown on standard sounding balloons and small, unmanned aerial vehicles (UAVs). The amount of solid or liquid water is important to the study of atmospheric processes and behavior. Previous sensing techniques relied on strongly heating the incoming air, which requires a major energy input that cannot be achieved on sounding balloons or small UAVs.

  20. Testing in a stratospheric balloon of a semiconductor detector altimeter

    International Nuclear Information System (INIS)

    Gilly, L.; Jourdan, P.

    1968-01-01

    An altimeter containing a semiconductor detector has been operated on flight. We have used a stratospheric balloon launched from AIRE-SUR-ADOUR with the C.N.E.S. collaboration. During this assay two apparatus have been used. The first allowed to follow the balloon during its ascension and descent, the second to follow its evolution at its maximum altitude. Informations transmitted by radio and recorded on Magnetophon, have been studied after the flight. Results are identical with these given by the barometer used by the C.N.E.S. in this essay. (authors) [fr

  1. Tethered balloon-based measurements of meteorological variables and aerosols

    Science.gov (United States)

    Sentell, R. J.; Storey, R. W.; Chang, J. J. C.; Jacobsen, S. J.

    1976-01-01

    Tethered balloon based measurements of the vertical distributions of temperature, humidity, wind speed, and aerosol concentrations were taken over a 4-hour period beginning at sunrise on June 29, 1976, at Wallops Island, Virginia. Twelve consecutive profiles of each variable were obtained from ground to about 500 meters. These measurements were in conjuction with a noise propagation study on remotely arrayed acoustic range (ROMAAR) at Wallops Flight Center. An organized listing of these vertical soundings is presented. The tethered balloon system configuration utilized for these measurements is described.

  2. A tethered balloon system for observation of atmospheric temperature inversion

    International Nuclear Information System (INIS)

    Hayashi, Takashi; Kakuta, Michio

    1979-05-01

    In environmental assessment of near-shore nuclear plants, information is often required on the development of internal boundary layer (IBL) and associated fumigation condition. Single tower data is not sufficient to clarify the site-dependent IBL structure that affects the atmospheric diffusion in shoreline-stack-site boundary complex. A tethered balloon system has been developed, which comprises a fixed point kitoon and a car-borne small balloon. The system enables us to measure the detailed time-space distribution of temperature without much man-power. The system and example of field observations with it are described. (author)

  3. Magnetic X-points, edge localized modes, and stochasticity

    International Nuclear Information System (INIS)

    Sugiyama, L. E.; Strauss, H. R.

    2010-01-01

    Edge localized modes (ELMs) near the boundary of a high temperature, magnetically confined toroidal plasma represent a new type of nonlinear magnetohydrodynamic (MHD) plasma instability that grows through a coherent plasma interaction with part of a chaotic magnetic field. Under perturbation, the freely moving magnetic boundary surface with an X-point splits into two different limiting asymptotic surfaces (manifolds), similar to the behavior of a hyperbolic saddle point in Hamiltonian dynamics. Numerical simulation using the extended MHD code M3D shows that field-aligned plasma instabilities, such as ballooning modes, can couple to the ''unstable'' manifold that forms helical, field-following lobes around the original surface. Large type I ELMs proceed in stages. Initially, a rapidly growing ballooning outburst involves the entire outboard side. Large plasma fingers grow well off the midplane, while low density regions penetrate deeply into the plasma. The magnetic field becomes superficially stochastic. A secondary inboard edge instability causes inboard plasma loss. The plasma gradually relaxes back toward axisymmetry, with diminishing cycles of edge instability. Poloidal rotation of the interior and edge plasma may be driven. The magnetic tangle constrains the early nonlinear ballooning, but may encourage the later inward penetration. Equilibrium toroidal rotation and two-fluid diamagnetic drifts have relatively small effects on a strong MHD instability. Intrinsic magnetic stochasticity may help explain the wide range of experimentally observed ELMs and ELM-free behavior in fusion plasmas, as well as properties of the H-mode and plasma edge.

  4. Long-Term Follow-up After Embolization of Pulmonary Arteriovenous Malformations with Detachable Silicone Balloons

    DEFF Research Database (Denmark)

    Andersen, Poul Erik; Kjeldsen, Anette D

    2008-01-01

    ) with pulmonary angiography. Fifty-four percent of the balloons were deflated at latest radiographic chest film follow-up, but at pulmonary angiographic follow-up all embolized malformations were without flow irrespective of whether or not the balloons were visible. Detachable silicone balloons are not available...

  5. 78 FR 18533 - Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances

    Science.gov (United States)

    2013-03-27

    ... Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances AGENCY: Federal Aviation Administration... Hot Air Balloons Ltd female ACME threaded hose connectors, part numbers HS6139 and HS6144, installed... follows: * * * * * (c) Applicability This AD applies to Lindstrand Hot Air Balloons Ltd female ACME...

  6. 77 FR 64763 - Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances

    Science.gov (United States)

    2012-10-23

    ... Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances AGENCY: Federal Aviation Administration... propose to adopt a new airworthiness directive (AD) for certain Lindstrand Hot Air Balloons Ltd female... identified in this proposed AD, contact Lindstrand Hot Air Balloons Ltd., Maesbury Road, Oswestry, Shropshire...

  7. 75 FR 63086 - Great Mississippi Balloon Race and Fireworks Safety Zone; Lower Mississippi River, Mile Marker...

    Science.gov (United States)

    2010-10-14

    ... flying hot air balloons transiting across the Lower Mississippi River. Entry into this zone is prohibited... mariners from the safety hazards associated with a fireworks display and low flying hot air balloons... mariners from the safety hazards associated with a fireworks display and low flying hot air balloons...

  8. 78 FR 9785 - Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances

    Science.gov (United States)

    2013-02-12

    ... Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances AGENCY: Federal Aviation Administration... airworthiness directive (AD) for certain Lindstrand Hot Air Balloons Ltd female ACME threaded hose connectors...., Washington, DC 20590. For service information identified in this AD, contact Lindstrand Hot Air Balloons Ltd...

  9. The next generation balloon-borne large aperture submillimeter telescope (BLAST-TNG)

    Science.gov (United States)

    Dober, Bradley Jerald

    Large areas of astrophysics, such as precision cosmology, have benefited greatly from large maps and datasets, yielded by telescopes of ever-increasing number and ability. However, due to the unique challenges posed by submillimeter polarimetry, the study of molecular cloud dynamics and star formation remain stunted. Previously, polarimetry data was limited to a few vectors on only the brightest areas of molecular clouds. This made drawing statistically-driven conclusions a daunting task. However, the successful flight of the Balloon-born Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) generated maps with thousands of independent polarization measurements of molecular clouds, and ushered in a new era of empirical modeling of molecular cloud dynamics. Now that the potential benefits from large-scale maps of magnetic fields in molecular clouds had been identified, a successor that would truly unlock the secrets must be born. The Next Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG), the successor to BLASTPol, has the ability to make larger and more detailed maps of magnetic fields in molecular clouds. It will push the field of star formation into a statistics-driven, empirical realm. With these large, detailed datasets, astronomers will be able to find new relationships between the dust dynamics and the magnetic fields. The field will surge to a new level of understanding. One of the key enabling technologies of BLAST-TNG is its three arrays of polarization-sensitive Microwave Kinetic Inductance Detectors (MKIDs). MKIDs are superconducting RLC circuits with a resonant frequency that shifts proportionally to the amount of incident radiation. The key feature of MKIDs is that thousands of detectors, each with their own unique resonant frequency, can be coupled to the same readout line. This technology will be able to drive the production of large-scale monolithic arrays, containing tens or hundreds of thousands of detectors

  10. Trapped particle stability for the kinetic stabilizer

    Science.gov (United States)

    Berk, H. L.; Pratt, J.

    2011-08-01

    A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favourable field-line curvature exists. The window of operation is determined for achieving magnetohydrodynamic (MHD) stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analysed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic-stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore, a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabilizer to the central region.

  11. Balloon dilatation of the esophageal stricture in infants and children

    International Nuclear Information System (INIS)

    Choo, Sung Wook; Kim, In One; Kim, Woo Sun; Yeon, Kyung Mo; Kim, Woo Ki; Park, Kwi Won; Han, Man Chung; Lee, Gi Jae; Yu, Pil Mun

    1992-01-01

    Balloon dilatation has been applied in treating of various pathologic narrowing of the hollow viscus. It is now accepted as a very effective modality especially in treating esophageal stenosis obviating surgical procedure. We performed 128 balloon dilatations in 29 patients with the number of dilatations in each patient ranging from once to 12 times. The age distribution of the patients was from 3 weeks to 6 years, with the median age of 3 months. Twenty nine patients consisted of 25 postoperative esophageal strictures (21 esophageal atresia with tracheoesophageal fistula, 1 congenital esophageal stenosis, 2 tracheobronchial remnant, and 1 congenital esophageal stenosis with esophageal atresia), 2 achalasia, 1 congenital esophageal stenosis, and 1 corrosive esophagitis. We had successful dilatation in 22 patients, who showed subsequent relief of symptoms and improvement in the diameter of stenotic segment. In 14 patients, esophageal perforation occurred during the procedure, one requiring emergency thoracotomy and the other three conservative management. Seven patients had no improvement in stenotic sites after several balloon dilatations. Failed cases were congenital stenosis, achalasia, corrosive esophagitis and four postoperative strictures. We believe that balloon dilatation is the procedure of choice in the treatment of postoperative esophageal stricture in infants and children and is a safe method as the perforation which can complicate the procedure could be managed conservatively

  12. Malfunctioning Plastic Biliary Endoprosthesis: Percutaneous Transhepatic Balloon Pulling Technique

    Directory of Open Access Journals (Sweden)

    Umberto G. Rossi

    2013-01-01

    Full Text Available Percutaneous transhepatic removal techniques for malfunctioning plastic biliary endoprosthesis are considered safe and efficient second-line strategies, when endoscopic procedures are not feasible. We describe the percutaneous transhepatic balloon pulling technique in a patient with an unresectable malignant hilar cholangiocarcinoma.

  13. Balloon dacryocystoplasty study in the management of adult epiphora.

    LENUS (Irish Health Repository)

    Fenton, S

    2012-02-03

    PURPOSE: To determine the efficacy of dacryocystoplasty with balloon dilation in the treatment of acquired obstruction of the nasolacrimal system in adults. METHODS: Balloon dacryocystoplasty was performed in 52 eyes of 42 patients under general anaesthetic. A Teflon-coated guidewire was introduced through the canaliculus and manipulated through the nasolacrimal system and out of the nasal aperture. A 4 mm wide 3 cm coronary angioplasty balloon catheter was threaded over the guidewire in a retrograde fashion and dilated at the site of obstruction. RESULTS: There was complete obstruction in 30% of cases and partial obstruction in 70%. The most common site of obstruction was the nasolacrimal duct. The procedure was technically successful in 94% of cases. The overall re-obstruction rate was 29% within 1 year of the procedure. There was an anatomical failure rate of 17% for partial obstruction and 69% for complete obstruction within 1 year. CONCLUSIONS: Balloon dacryocystoplasty has a high recurrence rate. There may be a limited role for this procedure in partial obstructions. Further refinements of the procedure are necessary before it can be offered as a comparable alternative to a standard surgical dacryocystorhinostomy.

  14. Balloon dilatation of the esophageal stricture in infants and children

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Sung Wook; Kim, In One; Kim, Woo Sun; Yeon, Kyung Mo; Kim, Woo Ki; Park, Kwi Won; Han, Man Chung [Seoul Natioal University College of Medicine, Seoul (Korea, Republic of); Lee, Gi Jae [Inje University Paik Hospital, Seoul (Korea, Republic of); Yu, Pil Mun [Dankuk University College of Medicine, Seoul (Korea, Republic of)

    1992-09-15

    Balloon dilatation has been applied in treating of various pathologic narrowing of the hollow viscus. It is now accepted as a very effective modality especially in treating esophageal stenosis obviating surgical procedure. We performed 128 balloon dilatations in 29 patients with the number of dilatations in each patient ranging from once to 12 times. The age distribution of the patients was from 3 weeks to 6 years, with the median age of 3 months. Twenty nine patients consisted of 25 postoperative esophageal strictures (21 esophageal atresia with tracheoesophageal fistula, 1 congenital esophageal stenosis, 2 tracheobronchial remnant, and 1 congenital esophageal stenosis with esophageal atresia), 2 achalasia, 1 congenital esophageal stenosis, and 1 corrosive esophagitis. We had successful dilatation in 22 patients, who showed subsequent relief of symptoms and improvement in the diameter of stenotic segment. In 14 patients, esophageal perforation occurred during the procedure, one requiring emergency thoracotomy and the other three conservative management. Seven patients had no improvement in stenotic sites after several balloon dilatations. Failed cases were congenital stenosis, achalasia, corrosive esophagitis and four postoperative strictures. We believe that balloon dilatation is the procedure of choice in the treatment of postoperative esophageal stricture in infants and children and is a safe method as the perforation which can complicate the procedure could be managed conservatively.

  15. Balloon-assisted coiling through a 5-French system

    International Nuclear Information System (INIS)

    White, J. Bradley; Layton, Kennith F.; Kallmes, David F.; Cloft, Harry J.

    2007-01-01

    We present a catheter technique that utilizes a 5F system for the purpose of balloon-assisted coiling in the setting of intracranial aneurysms. A standard 5F short sheath is placed in the common femoral artery, and a 5F diagnostic catheter is placed through the sheath and used for selective vessel angiography. When endovascular intervention is pursued, the diagnostic catheter is placed in the appropriate vessel and systemic heparinization is ensured. Over an exchange length wire, the 5F vertebral catheter and 5F short sheath are exchanged for a 5F Shuttle (Cook) sheath. We then routinely place a 10, 14 or 18 microcatheter over an appropriately gauged microguidewire into the aneurysm. As needed, balloon catheters are then placed across the neck of the aneurysm for remodeling purposes. During the course of the procedure, control angiography is performed through the Shuttle sheath. Following the placement of coils, the microcatheter and balloon catheter are removed and a final biplane image is obtained via the 5F Shuttle sheath. This technique has been employed in 15 patients who required balloon-assisted coiling of an intracranial aneurysm. There were no technical difficulties or arterial access site complications from the procedures. Catheter mobility and torque were not affected, nor was the quality of our imaging. We conclude that this small-diameter system provides ample ''room'' for catheter placement and interventional treatment while reducing the known risks of postprocedural complications. Angiographic images remain excellent and are comparable to those obtained by larger catheters. (orig.)

  16. 75 FR 33838 - National Environmental Policy Act; Scientific Balloon Program

    Science.gov (United States)

    2010-06-15

    ...[supreg] portable document format at the following address: http://sites.wff.nasa.gov/code250/BPO_PEA.php... over 25 years. Balloons are used to collect scientific data and conduct research on the atmosphere and... has seen a dramatic increase in sophistication of experiments and demands for service. Due to the...

  17. Achilles tests finally nail PWR fuel clad ballooning fears

    International Nuclear Information System (INIS)

    Dore, P.; McMinn, K.

    1992-01-01

    A conclusive series of experiments carried out by AEA Reactor Services at its Achilles rig in the UK has finally allayed fears that fuel clad ballooning is a major safety problem for Sizewell B, Britain's first Pressurized Water Reactor. The experiments are described in this article. (author)

  18. 75 FR 77673 - National Environmental Policy Act: Scientific Balloon Program

    Science.gov (United States)

    2010-12-13

    ... Proposed Action are not anticipated. Air Quality: Vehicular travel by research scientists and students to... year during balloon campaigns at CSBF Fort Sumner from the purchase of food, supplies, and lodging by CSBF staff and research scientists and students. An adequate supply of restaurants and lodging...

  19. Balloon observations of galactic and extragalactic objects at 100 microns.

    Science.gov (United States)

    Hoffmann, W. F.

    1972-01-01

    Recent far-infrared balloon-borne instruments have yielded observations of a number of bright sources at 100 microns. Many of these coincide with HII regions where molecular line emision has been detected. There is some indication of 100 micron emission which does not coincide with radio measurements.

  20. Meshed-Pumpkin Super-Pressure Balloon Design

    Science.gov (United States)

    Jones, Jack; Yavrouian, Andre

    2003-01-01

    An improved, lightweight design has been proposed for super-pressure balloons used to carry scientific instruments at high altitudes in the atmosphere of Earth for times as long as 100 days. [A super-pressure balloon is one in which the pressure of the buoyant gas (typically, helium) is kept somewhat above ambient pressure in order to maintain approximately constant density and thereby regulate the altitude.] The proposed design, called "meshed pumpkin," incorporates the basic concept of the pumpkin design, which is so named because of its appearance. The pumpkin design entails less weight than does a spherical design, and the meshed-pumpkin design would reduce weight further. The basic idea of the meshed-pumpkin design is to reinforce the membrane of a pumpkin balloon by attaching a strong, lightweight fabric mesh to its outer surface. The reinforcement would make it possible to reduce the membrane mass to one-third or less of that of the basic pumpkin design while retaining sufficient strength to enable the balloon to remain at approximately constant altitude for months.

  1. 28. Critical pulmonary valve stenosis: Medical management beyond balloon dilation

    Directory of Open Access Journals (Sweden)

    Muhammad Arif Khan

    2015-10-01

    Conclusion: Phentolamine and/or Captopril have a therapeutic role in neonates with critical PVS who remain oxygen dependent after balloon dilation. Both medicationslead to vasodilatation of pulmonary and systemic vascularity. They facilitate inflowto the right ventricle. Right to left shunt across a PFO or/ ASD minimizesand saturation improves leading to a significantreduction in length of hospitalization.

  2. Balloon test project: Cosmic Ray Antimatter Calorimeter (CRAC)

    Science.gov (United States)

    Christy, J. C.; Dhenain, G.; Goret, P.; Jorand, J.; Masse, P.; Mestreau, P.; Petrou, N.; Robin, A.

    1984-01-01

    Cosmic ray observations from balloon flights are discussed. The cosmic ray antimatter calorimeter (CRAC) experiment attempts to measure the flux of antimatter in the 200-600 Mev/m energy range and the isotopes of light elements between 600 and 1,000 Mev/m.

  3. The Micro-Instrumentation Package: A Solution to Lightweight Ballooning

    Science.gov (United States)

    Juneau, Jill

    This paper discusses the design and testing of an over the horizon (OTH) light weight telemetry and termination system that can be used for small ballooning payloads. Currently, the Columbia Scientific Balloon Facility (CSBF) provides telemetry for the science payload by integrating one of two types of support packages. The type of support package integrated depends on whether the flight will stay in range of line of sight (LOS) or will exceed LOS requiring the use of over the horizon (OTH) telemetry. The weights of these systems range from 100 pounds to 350 pounds depending upon the use of redundant systems, equipment for high data rates, and batteries and/or solar panels for power requirements. These weight values are not as significant for larger payloads but can be crippling for smaller payloads. In addition, these support package systems are fairly expensive, placing a high importance on recovery. A lightweight and inexpensive telemetry system could be beneficial for various reasons. First, it would allow scientists to fly lightweight payloads on large balloons reaching even higher altitudes. Second, scientists could fly lightweight payloads on less expensive balloons such as meteorological balloons. Depending on the payload, these flights could be fairly inexpensive and even disposable. Third, a compact telemetry system on any balloon will free up more room for the science portion of the payload. In response, a compact telemetry/termination system called the Micro-Instrumentation Package (MIP) was developed. The MIP provides uplink and downlink communications, an interface to the science, housekeeping information including global positioning system (GPS) position, and relays. Instead of a power-hungry microprocessor, the MIP's central consists of a microcontroller. Microcontrollers are lower power, easily programmed, and can be purchased for less than ten dollars. For uplink and downlink telemetry, the MIP uses an LOS serial transceiver and an Iridium unit

  4. Two-fluid effects on pressure-driven modes in a heliotron device

    International Nuclear Information System (INIS)

    Miura, H.; Ito, A.; Sato, M.; Goto, R.; Hatori, T.

    2014-10-01

    Two-fluid effects on the ballooning or pressure-driven unstable modes are studied numerically to understand physics in linear and nonlinear evolution of them in a heliotron device. Full 3D simulations for β 0 = 5% unstable magnetic configuration of the large helical device show that the introduction of the two-fluid term brings about broader radial profile and higher growth rate in the linear stage of the evolution, weakened parallel heat conduction, and lead to a saturation profile worse than that in the single-fluid MHD simulation. The numerical results show that suppression of high wave-number modes enhance the growth of low wave-number modes. The two-fluid effects and a plausible mild saturation of ballooning modes is discussed. (author)

  5. Ozone profiles from tethered balloon measurements in an urban plume experiment

    Science.gov (United States)

    Youngbluth, O., Jr.; Storey, R. W.; Clendenin, C. G.; Jones, S.; Leighty, B.

    1981-01-01

    NASA Langley Research Center used two tethered balloon systems to measure ozone in the general area of Norfolk, Va. The large balloon system which has an altitude range of 1,500 meters was located at Wallops Island, Va., and the smaller balloon which has an altitude range of 900 meters was located at Chesapeake, Va. Each balloon system measured ozone, temperature, humidity, wind speed, and wind direction from ground to its maximum altitude. From these measurements and from the location of the balloon sites, areas of ozone generation and ozone transport may be inferred. The measurements which were taken during August 1979 are discussed as well as the measurement techniques.

  6. Modification of H-Mode Pedestal Instabilities in the DIII-D Tokamak

    International Nuclear Information System (INIS)

    J.R. Ferron; M.S. Chu; G.L. Jackson; L.L. Lao; R.L. Miller; T.H. Osborne; P.B. Snyder; E.J. Strait; T.S. Taylor; A.D. Turnbull; A.M. Garofalo; M.A. Makowski; B.W. Rice; M.S. Chance; L.R. Baylor; M. Murakami; M.R. Wade

    1999-01-01

    Through comparison of experiment and ideal magnetohydrodynamic (MHD) theory, modes driven in the edge region of tokamak H-mode discharges [Type I edge-localized modes (ELMs)] are shown to result from low toroidal mode number (n) instabilities driven by pressure gradient and current density. The mode amplitude and frequency are functions of the discharge shape. Reductions in mode amplitude are observed in discharge shapes with either high squareness or low triangularity where the low-n stability threshold in the edge pressure gradient is predicted to be reduced and the most unstable mode is expected to have higher values of n. The importance of access to the ballooning mode second stability regime is demonstrated through the changes in the ELM character that occur when second regime access is not available. An edge stability model is presented that predicts that there is a threshold value of n for second regime access and that the most unstable mode has n near this threshold

  7. Spin modes

    International Nuclear Information System (INIS)

    Gaarde, C.

    1985-01-01

    An analysis of spectra of (p,n) reactions showed that they were very selective in exciting spin modes. Charge exchange reactions at intermediate energies give important new understanding of the M1-type of excitations and of the spin structure of continuum p spectra in general. In this paper, the author discusses three charge exchange reactions: (p,n); ( 3 H,t); and (d,2p) at several targets. Low-lying states and the Δ region are discussed separately. Finally, the charge exchange reaction with heavy ion beams is briefly discussed. (G.J.P./Auth.)

  8. National Report on the NASA Sounding Rocket and Balloon Programs

    Science.gov (United States)

    Eberspeaker, Philip; Fairbrother, Debora

    2013-01-01

    The U. S. National Aeronautics and Space Administration (NASA) Sounding Rockets and Balloon Programs conduct a total of 30 to 40 missions per year in support of the NASA scientific community and other users. The NASA Sounding Rockets Program supports the science community by integrating their experiments into the sounding rocket payloads, and providing both the rocket vehicle and launch operations services. Activities since 2011 have included two flights from Andoya Rocket Range, more than eight flights from White Sands Missile Range, approximately sixteen flights from Wallops Flight Facility, two flights from Poker Flat Research Range, and four flights from Kwajalein Atoll. Other activities included the final developmental flight of the Terrier-Improved Malemute launch vehicle, a test flight of the Talos-Terrier-Oriole launch vehicle, and a host of smaller activities to improve program support capabilities. Several operational missions have utilized the new Terrier-Malemute vehicle. The NASA Sounding Rockets Program is currently engaged in the development of a new sustainer motor known as the Peregrine. The Peregrine development effort will involve one static firing and three flight tests with a target completion data of August 2014. The NASA Balloon Program supported numerous scientific and developmental missions since its last report. The program conducted flights from the U.S., Sweden, Australia, and Antarctica utilizing standard and experimental vehicles. Of particular note are the successful test flights of the Wallops Arc Second Pointer (WASP), the successful demonstration of a medium-size Super Pressure Balloon (SPB), and most recently, three simultaneous missions aloft over Antarctica. NASA continues its successful incremental design qualification program and will support a science mission aboard WASP in late 2013 and a science mission aboard the SPB in early 2015. NASA has also embarked on an intra-agency collaboration to launch a rocket from a balloon to

  9. A study on usefulness of balloon cholangiography in operating ERCP

    International Nuclear Information System (INIS)

    Son, Soon Yong

    1997-01-01

    Purpose of this paper is to extend help for clinical application in balloon cholangiography on patients who have undergone endoscopic sphincterotomy, impacted stones of intrahepatic duct, and missed bile duct because of other diseases in operating endoscopic retrograde cholangio pancreatography. This study was done for the patients who had clinical signs of biliary diseases from January to December in 1996. We studied 45 patients who had endoscopic sphincterotomy, re-examination after interventional treatment of the endoscopic retrograde cholangio pancreatography, and uncertain diagnosis due to common bile duct and intrahepatic duct those are not filled with contrast media. Balloon cholangiography was performed in case of uncertain diagnosis while operating endoscopic retrograde cholangio pancreatography. First of all, we insert balloon catheter into the working channel of treatment jejunofiberscope and remove treatment jejunofiberscope after ballooning, and lastly take biliary tract X-ray after injection and changing position of patient. The results of this study were as follows. (1) In classification of diseases, stones of gall bladder, those of common bile duct, and those of intrahepatic duct were 30 cases, fistula was 1 case. (2) In total cases of 45, only diagnosis were 25 cases, interventional treatment were 20 cases. (3) In case of interventional treatment, endoscopic sphincterotomy and endoscopic nasobiliary drainage, and stone removal were about the same, 7, 7, 6 respectively. Balloon cholangiography will be useful to prevent patients from having repeated and unnecessary studies for the cases above explained. It is considered that this study will be useful for clinical application in terms of reducing medical expenses, pain while examination, and consultation hours

  10. High Altitude Infrasound Measurements using Balloon-Borne Arrays

    Science.gov (United States)

    Bowman, D. C.; Johnson, C. S.; Gupta, R. A.; Anderson, J.; Lees, J. M.; Drob, D. P.; Phillips, D.

    2015-12-01

    For the last fifty years, almost all infrasound sensors have been located on the Earth's surface. A few experiments consisting of microphones on poles and tethered aerostats comprise the remainder. Such surface and near-surface arrays likely do not capture the full diversity of acoustic signals in the atmosphere. Here, we describe results from a balloon mounted infrasound array that reached altitudes of up to 38 km (the middle stratosphere). The balloon drifted at the ambient wind speed, resulting in a near total reduction in wind noise. Signals consistent with tropospheric turbulence were detected. A spectral peak in the ocean microbarom range (0.12 - 0.35 Hz) was present on balloon-mounted sensors but not on static infrasound stations near the flight path. A strong 18 Hz signal, possibly related to building ventilation systems, was observed in the stratosphere. A wide variety of other narrow band acoustic signals of uncertain provenance were present throughout the flight, but were absent in simultaneous recordings from nearby ground stations. Similar phenomena were present in spectrograms from the last balloon infrasound campaign in the 1960s. Our results suggest that the infrasonic wave field in the stratosphere is very different from that which is readily detectable on surface stations. This has implications for modeling acoustic energy transfer between the lower and upper atmosphere as well as the detection of novel acoustic signals that never reach the ground. Our work provides valuable constraints on a proposed mission to detect earthquakes on Venus using balloon-borne infrasound sensors.

  11. Stochastic theory of interfacial enzyme kinetics: A kinetic Monte Carlo study

    International Nuclear Information System (INIS)

    Das, Biswajit; Gangopadhyay, Gautam

    2012-01-01

    Graphical abstract: Stochastic theory of interfacial enzyme kinetics is formulated. Numerical results of macroscopic phenomenon of lag-burst kinetics is obtained by using a kinetic Monte Carlo approach to single enzyme activity. Highlights: ► An enzyme is attached with the fluid state phospholipid molecules on the Langmuir monolayer. ► Through the diffusion, the enzyme molecule reaches the gel–fluid interface. ► After hydrolysing a phospholipid molecule it predominantly leaves the surface in the lag phase. ► The enzyme is strictly attached to the surface with scooting mode of motion and the burst phase appears. - Abstract: In the spirit of Gillespie’s stochastic approach we have formulated a theory to explore the advancement of the interfacial enzyme kinetics at the single enzyme level which is ultimately utilized to obtain the ensemble average macroscopic feature, lag-burst kinetics. We have provided a theory of the transition from the lag phase to the burst phase kinetics by considering the gradual development of electrostatic interaction among the positively charged enzyme and negatively charged product molecules deposited on the phospholipid surface. It is shown that the different diffusion time scales of the enzyme over the fluid and product regions are responsible for the memory effect in the correlation of successive turnover events of the hopping mode in the single trajectory analysis which again is reflected on the non-Gaussian distribution of turnover times on the macroscopic kinetics in the lag phase unlike the burst phase kinetics.

  12. Immediate balloon deflation for prevention of persistent phrenic nerve palsy during pulmonary vein isolation by balloon cryoablation.

    Science.gov (United States)

    Ghosh, Justin; Sepahpour, Ali; Chan, Kim H; Singarayar, Suresh; McGuire, Mark A

    2013-05-01

    Persistent phrenic nerve palsy is the most frequent complication of cryoballoon ablation for atrial fibrillation and can be disabling. To describe a technique-immediate balloon deflation (IBD)-for the prevention of persistent phrenic nerve palsy, provide data for its use, and describe in vitro simulations performed to investigate the effect of IBD on the atrium and pulmonary vein. Cryoballoon procedures for atrial fibrillation were analyzed retrospectively (n = 130). IBD was performed in patients developing phrenic nerve dysfunction (n = 22). In vitro simulations were performed by using phantoms. No adverse events occurred, and all patients recovered normal phrenic nerve function before leaving the procedure room. No patient developed persistent phrenic nerve palsy. The mean cryoablation time to onset of phrenic nerve dysfunction was 144 ± 64 seconds. Transient phrenic nerve dysfunction was seen more frequently with the 23-mm balloon than with the 28-mm balloon (11 of 39 cases vs 11 of 81 cases; P = .036). Balloon rewarming was faster following IBD. The time to return to 0 and 20° C was shorter in the IBD group (6.7 vs 8.9 seconds; P = .007 and 16.7 vs 37.6 seconds; Pphrenic nerve palsy. Simulations suggest that IBD is unlikely to damage the atrium or pulmonary vein. Copyright © 2013 Heart Rhythm Society. All rights reserved.

  13. Embolization of carotid-cavernous fistula using a silicone balloon and a tracker-catheter system

    International Nuclear Information System (INIS)

    Kim, Sun Yong; Cho, Kil Ho; Park, Bok Hwan

    1992-01-01

    With the recent introduction and development of the detachable balloon system, it has become the treatment of choice in the management of carotid cavernous fistulas(CCFs). But, since most delivery systems for embolization of CCF mainly depend on flow guidance for balloon delivery, in case of small fistula, pseudo aneurysm and arterialized venous collaterals, failure of balloon embolization can occur. To overcome these limitation, the authors designed and used a new versatile, steerable, and flow-guided detachable balloon system by using a Tracker catheter system with silicone or latex balloons. Using this maneuver, we could get successful fistula occlusion in 7 out of 8 patients (silicone balloon). But in one case, we had to occlude the internal carotid artery at the fistula site, proximal and distal cervical portions of the internal carotid artery. This balloon delivery system proved to provide high selectivity for fistula and relatively ease of handing

  14. Microtearing modes

    International Nuclear Information System (INIS)

    Garbet, X.; Mourgues, F.; Samain, A.; Zou, X.

    1990-01-01

    A serious degradation of confinement with additional heating is commonly observed on most tokamaks. The microtearing modes could provide an explanation for this experimental fact. They are driven linearly unstable by diamagnetism in collisional regimes, but it may be shown that the collisions in non linear regimes provide a small diffusion coefficient which can be only significant at the plasme edge. In the bulk of the plasma, the microtearing turbulence could play a basic role if it is unstable in the collisionless regime. While it is linearly stable without collisions, it could be driven unstable in realistic regimes by the radial diffusion it induces. To study this effect, we have used a model where the non linear action of the modes on a given helicity component is represented by a diffusion operator. They are found unstable for reasonable β p =2μ o nT/B 2 p , with a special radial profile of the potential vector A. The problem arises the validity of this model where non linearities in the trajectories behaviour are replaced by the diffusion which broadens resonances. To test this procedure, we calculate the actual electron distribution function when it is determined by the ergodicity of the field lines. We compute the correlations of the distribution function with the magnetic perturbation and compare them with the analytical expressions derived from the resonance broadening model. (author) 3 refs., 2 figs

  15. Towards understanding edge localised mode mitigation by resonant magnetic perturbations in MAST

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, I. T.; Kirk, A.; Ham, C. J.; Harrison, J. R.; Liu, Y. Q.; Saarelma, S.; Scannell, R.; Thornton, A. J.; Team, MAST [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Becoulet, M.; Orain, F. [Association Euratom/CEA, CEA Cadarache, IRFM, F-13108, St. Paul-lez-Durance (France); Cooper, W. A. [CRPP, Association EURATOM/Confédération Suisse, EPFL, 1015 Lausanne (Switzerland); Pamela, S. [IIFS-PIIM. Aix Marseille Université—CNRS, 13397 Marseille Cedex 20 (France)

    2013-05-15

    Type-I Edge Localised Modes (ELMs) have been mitigated in MAST through the application of n=3,4, and 6 resonant magnetic perturbations. For each toroidal mode number of the non-axisymmetric applied fields, the frequency of the ELMs has been increased significantly, and the peak heat flux on the divertor plates reduced commensurately. This increase in ELM frequency occurs despite a significant drop in the edge pressure gradient, which would be expected to stabilise the peeling-ballooning modes thought to be responsible for type-I ELMs. Various mechanisms which could cause a destabilisation of the peeling-ballooning modes are presented, including pedestal widening, plasma rotation braking, three dimensional corrugation of the plasma boundary, and the existence of radially extended lobe structures near to the X-point. This leads to a model aimed at resolving the apparent dichotomy of ELM control, which is to say ELM suppression occurring due to the pedestal pressure reduction below the peeling-ballooning stability boundary, whilst the reduction in pressure can also lead to ELM mitigation, which is ostensibly a destabilisation of peeling-ballooning modes. In the case of ELM mitigation, the pedestal broadening, 3d corrugation, or lobes near the X-point degrade ballooning stability so much that the pedestal recovers rapidly to cross the new stability boundary at lower pressure more frequently, whilst in the case of suppression, the plasma parameters are such that the particle transport reduces the edge pressure below the stability boundary, which is only mildly affected by negligible rotation braking, small edge corrugation or short, broad lobe structures.

  16. Effects of a sheared toroidal rotation on the stability boundary of the MHD modes in the tokamak edge pedestal

    International Nuclear Information System (INIS)

    Aiba, N.; Tokuda, S.; Oyama, N.; Ozeki, T.; Furukawa, M.

    2009-01-01

    Effects of a sheared toroidal rotation are investigated numerically on the stability of the MHD modes in the tokamak edge pedestal, which relate to the type-I edge-localized mode. A linear MHD stability code MINERVA is newly developed for solving the Frieman-Rotenberg equation that is the linear ideal MHD equation with flow. Numerical stability analyses with this code reveal that the sheared toroidal rotation destabilizes edge localized MHD modes for rotation frequencies which are experimentally achievable, though the ballooning mode stability changes little by rotation. This rotation effect on the edge MHD stability becomes stronger as the toroidal mode number of the unstable MHD mode increases when the stability analysis was performed for MHD modes with toroidal mode numbers smaller than 40. The toroidal mode number of the unstable MHD mode depends on the stabilization of the current-driven mode and the ballooning mode by increasing the safety factor. This dependence of the toroidal mode number of the unstable mode on the safety factor is considered to be the reason that the destabilization by toroidal rotation is stronger for smaller edge safety factors.

  17. Key factors of combustion from kinetics to gas dynamics

    CERN Document Server

    Rubtsov, Nikolai M

    2017-01-01

    This book summarizes the main advances in the mechanisms of combustion processes. It focuses on the analysis of kinetic mechanisms of gas combustion processes and experimental investigation into the interrelation of kinetics and gas dynamics in gas combustion. The book is complimentary to the one previously published, The Modes of Gaseous Combustion.

  18. Application of Chemical Kinetics to Deterioration of Foods.

    Science.gov (United States)

    Labuza, T. P.

    1984-01-01

    Possible modes of food deterioration (such as microbial decay, nonenzymatic browning, senescence, lipid oxidation) are reviewed. A basic mathematical approach to the kinetics of food deterioration, kinetic approach to accelerating shelf-life deterioration, and shelf-life predictions are discussed. (JN)

  19. Rehydration kinetics of freeze-dried carrots

    NARCIS (Netherlands)

    Vergeldt, F.J.; Dalen, van G.; Duijster, A.J.; Voda, A.; Khalloufi, S.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.; Sman, van der R.G.M.

    2014-01-01

    Rehydration kinetics by two modes of imbibition is studied in pieces of freeze-dried winter carrot, after different thermal pre-treatments. Water ingress at room temperature is measured in real time by in situ MRI and NMR relaxometry. Blanched samples rehydrate substantially faster compared to

  20. Correlations between quasi-coherent fluctuations and the pedestal evolution during the inter-edge localized modes phase on DIII-D

    International Nuclear Information System (INIS)

    Diallo, A.; Battaglia, D. J.; Guttenfelder, W.; Groebner, R. J.; Osborne, T. H.; Snyder, P. B.; Rhodes, T. L.; Smith, D. R.; Canik, J. M.

    2015-01-01

    Direct measurements of the pedestal recovery during an edge-localized mode cycle provide evidence that quasi-coherent fluctuations (QCFs) play a role in the inter-ELM pedestal dynamics. Using fast Thomson scattering measurements, the pedestal density and temperature evolutions are probed on sub-millisecond time scales to show a fast recovery of the density gradient compared to the temperature gradient. The temperature gradient appears to provide a drive for the onset of quasi-coherent fluctuations (as measured with the magnetic probe and the density diagnostics) localized in the pedestal. The amplitude evolution of these QCFs tracks the temperature gradient evolution including its saturation. Such correlation suggests that these QCFs play a key role in limiting the pedestal temperature gradient. The saturation of the QCFs coincides with the pressure gradient reaching the kinetic-ballooning mode (KBM) critical gradient as predicted by EPED1. Furthermore, linear microinstability analysis using GS2 indicates that the steep gradient is near the KBM threshold. Thus, the modeling and the observations together suggest that QCFs are consistent with dominant KBMs, although microtearing cannot be excluded as subdominant

  1. Correlations between quasi-coherent fluctuations and the pedestal evolution during the inter-edge localized modes phase on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, A.; Battaglia, D. J.; Guttenfelder, W. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States); Groebner, R. J.; Osborne, T. H.; Snyder, P. B. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Rhodes, T. L. [Physics and Astronomy Department, P.O. Box 957099, Los Angeles, California 90095-7099 (United States); Smith, D. R. [Department of Engineering Physics, 1500 Engineering Dr., Madison, Wisconsin 53706 (United States); Canik, J. M. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)

    2015-05-15

    Direct measurements of the pedestal recovery during an edge-localized mode cycle provide evidence that quasi-coherent fluctuations (QCFs) play a role in the inter-ELM pedestal dynamics. Using fast Thomson scattering measurements, the pedestal density and temperature evolutions are probed on sub-millisecond time scales to show a fast recovery of the density gradient compared to the temperature gradient. The temperature gradient appears to provide a drive for the onset of quasi-coherent fluctuations (as measured with the magnetic probe and the density diagnostics) localized in the pedestal. The amplitude evolution of these QCFs tracks the temperature gradient evolution including its saturation. Such correlation suggests that these QCFs play a key role in limiting the pedestal temperature gradient. The saturation of the QCFs coincides with the pressure gradient reaching the kinetic-ballooning mode (KBM) critical gradient as predicted by EPED1. Furthermore, linear microinstability analysis using GS2 indicates that the steep gradient is near the KBM threshold. Thus, the modeling and the observations together suggest that QCFs are consistent with dominant KBMs, although microtearing cannot be excluded as subdominant.

  2. Optimizing logistics for balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices by doing away with the indwelling balloon: concept and techniques.

    Science.gov (United States)

    Saad, Wael E; Nicholson, David B

    2013-06-01

    Since the conception of balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices 25 years ago, the placement of an indwelling balloon for hours has been central to the BRTO procedure. Numerous variables and variations of the BRTO procedure have been described, including methods to reduce sclerosant, combining percutaneous transhepatic obliteration, varying sclerosant, and using multiple sclerosants within the same procedure. However, the consistent feature of BRTO has always remained the indwelling balloon. Placing an indwelling balloon over hours for the BRTO procedure is a logistical burden that taxes the interventional radiology team and hospital resources. Substituting the balloon with hardware (coils or Amplatzer vascular plugs [AVPs] or both) is technically feasible and its risks most likely correlate with gastrorenal shunt (GRS) size. The current authors use packed 0.018- or 0.035-in coils or both for small gastric variceal systems (GRS size A and B) and AVPs for GRS sizes up to size E (from size A-E). The current authors recommend an indwelling balloon (no hardware substitute) for very large gastric variceal system (GRS size F). Substituting the indwelling balloon for hardware in size F and potentially size E GRS can also be risky. The current article describes the techniques of placing up to 16-mm AVPs through balloon occlusion guide catheters and then deflating the balloon once it has been substituted with the AVPs. In addition, 22-mm AVPs can be placed through sheaths once the balloon occlusion catheters are removed to further augment the 16-mm Amplatzer occlusion. To date, there are no studies describing, let alone evaluating, the clinical feasibility of performing BRTO without indwelling balloons. The described techniques have been successfully performed by the current authors. However, the long-term safety and effectiveness of these techniques is yet to be determined. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Resistive internal kink modes in a tokamak with high-pressure plasma

    International Nuclear Information System (INIS)

    Kuvshinov, B.N.; Mikhajlovskij, A.B.; Tatarinov, E.G.

    1988-01-01

    Theory of resistive internal kink modes in a tokamak with high-pressure plasma is developed. Equation for Fourie-image of disturbed displacment in a resistive layer ie derived with regard to effects of the fourth order by plasma pressure within the framework of single-liquid approach. In its structure this equation coincides with a similar equation for resistive balloon modes and has an exact solution expressed by degenerated hypergeometric function. A general dispersion equation for resistive kink modes is derived with regard to the effects indicated. It is shown that plasma pressure finiteness leads to the reduction of reconnection and tyring-mode increments

  4. Confinement improvement in H-mode-like plasmas in helical systems

    International Nuclear Information System (INIS)

    Itoh, K.; Sanuki, H.; Itoh, S.; Fukuyama, A.; Yagi, M.

    1993-06-01

    The reduction of the anomalous transport due to the inhomogeneous radial electric field is theoretically studied for toroidal helical plasmas. The self-sustained interchange-mode turbulence is analysed for the system with magnetic shear and magnetic hill. For the system with magnetic well like conventional stellarators, the ballooning mode turbulence is studied. Influence of the radial electric field inhomogeneity on the transport coefficients and fluctuations are quantitatively shown. Unified theory of the transport coefficients in the L-mode and H-mode-like plasmas are presented. (author)

  5. Kinetic theory of tearing instability

    International Nuclear Information System (INIS)

    Hazeltine, R.D.; Dobrott, D.; Wang, T.S.

    1975-01-01

    The guiding-center kinetic equation with Fokker-Planck collision term is used to study, in cylindrical geometry, a class of dissipative instabilities of which the classical tearing mode is an archetype. Variational solution of the kinetic equation obviates the use of an approximate Ohm's law or adiabatic assumption, as used in previous studies, and it provides a dispersive relation which is uniformly valid for any ratio of wave frequency to collision frequency. One result of using the rigorous collision operator is the prediction of a new instability. This instability, driven by the electron temperature gradient, is predicted to occur under the long mean-free path conditions of present tokamak experiments, and has significant features in common with the kink-like oscillations observed in such experiments

  6. Mode of action of Buddleja cordata verbascoside against Staphylococcus aureus.

    Science.gov (United States)

    Avila, J G; de Liverant, J G; Martínez, A; Martínez, G; Muñoz, J L; Arciniegas, A; Romo de Vivar, A

    1999-07-01

    We evaluate the mode of action of verbascoside obtained from Buddleja cordata against Staphylococcus aureus by killing kinetics and incorporation of precursors methods. Verbascoside induced lethal effect on S. aureus, by affecting protein synthesis and inhibiting leucine incorporation.

  7. In Situ Balloon-Borne Ice Particle Imaging in High-Latitude Cirrus

    Science.gov (United States)

    Kuhn, Thomas; Heymsfield, Andrew J.

    2016-09-01

    determine particle size distributions of cloud layers. Depending on how ice particles vary through the cloud, several layers per cloud with relatively uniform properties have been analysed. Preliminary results of the balloon campaign, targeting upper tropospheric, cold cirrus clouds, are presented here. Ice particles in these clouds were predominantly very small, with a median size of measured particles of around 50 µm and about 80 % of all particles below 100 µm in size. The properties of the particle size distributions at temperatures between -36 and -67 °C have been studied, as well as particle areas, extinction coefficients, and their shapes (area ratios). Gamma and log-normal distribution functions could be fitted to all measured particle size distributions achieving very good correlation with coefficients R of up to 0.95. Each distribution features one distinct mode. With decreasing temperature, the mode diameter decreases exponentially, whereas the total number concentration increases by two orders of magnitude with decreasing temperature in the same range. The high concentrations at cold temperatures also caused larger extinction coefficients, directly determined from cross-sectional areas of single ice particles, than at warmer temperatures. The mass of particles has been estimated from area and size. Ice water content (IWC) and effective diameters are then determined from the data. IWC did vary only between 1 × 10-3 and 5 × 10-3 g m-3 at temperatures below -40 °C and did not show a clear temperature trend. These measurements are part of an ongoing study.

  8. Nonlinear MHD and energetic particle modes in stellarators

    International Nuclear Information System (INIS)

    Strauss, H.R.; Fu, G.Y.; Park, W.; Breslau, J.; Sugiyama, L.E.

    2003-01-01

    The M3D (Multi-level 3D) project carries out simulation studies of plasmas using multiple levels of physics, geometry and grid models. The M3D code has been applied to ideal, resistive, two fluid, and hybrid simulations of compact quasi axisymmetric stellarators. When β exceeds a threshold, moderate toroidal mode number (n ∼ 10) modes grow exponentially, clearly distinguishable from the equilibrium evolution. The β limits are significantly higher than the infinite mode number ballooning limits. In the presence of resistivity, these modes occur well below the ideal limit. Their growth rate scaling with resistivity is similar to tearing modes. At low resistivity, the modes couple to resistive interchanges, which are unstable in most stellarators. Two fluid simulations with M3D show that resistive modes can be stabilized by diamagnetic drift. The two fluid computations are done with a realistic value of the Hall parameter, the ratio of ion skin depth to major radius. Hybrid gyrokinetic simulations with energetic particles indicate that global shear Alfven TAE - like modes can be destabilized in stellarators. Computations in a two-period compact stellarator obtained a predominantly n=1 toroidal mode with the expected TAE frequency. It is found that TAE modes are more stable in the two-period compact stellarator that in a tokamak with the same q and pressure profiles. M3D combines a two dimensional unstructured mesh with finite element discretization in poloidal planes, and fourth order finite differencing in the toroidal direction. (author)

  9. An analysis of the deployment of a pumpkin balloon at Mars

    Science.gov (United States)

    Rand, J. L.; Phillips, M. L.

    2004-01-01

    The design of large superpressure balloons has received significant attention in recent years due to the successful demonstration of various enabling technologies and materials. Of particular note is the "pumpkin" shaped balloon concept, which allows the stress in the envelope to be limited by the surface geometry. Unlike a sphere, where the radius used to determine the stress is determined by the volume of the balloon, the pumpkin utilizes a system of meridional tendons to react the loading in one direction, and form a number of lobes, which limit the stress in the circumferential direction. A suitable superpressure balloon has been designed using this technology which will carry 2 kg in the atmosphere of Mars. The deployment of this balloon is assumed to occur while falling on a decelerator suitably designed for the Mars atmosphere. The inflation is accomplished by a 10 kg system suspended at the nadir of the balloon. As the system falls toward the surface of the planet, helium gas is transferred into the balloon, forming a partially inflated system very similar to an ascending zero pressure balloon. This analysis incorporates the flow of the planetary gas around the inflating balloon which alters the pressure distribution and shape. As a result, stresses are seen to increase beyond the design values which will require the balloon to be redesigned to accommodate this type of dynamic deployment.

  10. Development of a Super-Pressure Balloon with an Improved Design

    Science.gov (United States)

    Izutsu, Naoki; Akita, Daisuke; Fuke, Hideyuki; Iijima, Issei; Kato, Yoichi; Kawada, Jiro; Matsushima, Kiyoho; Matsuzaka, Yukihiko; Mizuta, Eiichi; Nakada, Takashi; Nonaka, Naoki; Saito, Yoshitaka; Takada, Atsushi; Tamura, Keisuke; Yamada, Kazuhiko; Yoshida, Tetsuya

    A zero-pressure balloon used for scientific observation in the stratosphere has an unmanageable limitation that its floating altitude decreases during a nighttime because of temperature drop of the lifting gas. Since a super-pressure balloon may not change its volume, the lifetime can extend very long. We had introduced so called the ‘lobed-pumpkin’ type of super-pressure balloon that can realize a full-scale long-duration balloon and it will be in practical use in the very near future. As for larger super-pressure balloons, however, we still have some potential difficulties to be resolved. We here propose a new design suitable for a larger super-pressure balloon, which is roughly ‘lobed pumpkin with lobed cylinder’ and can adapt a single design for balloons of a wide range of volumes. Indoor inflation tests were successfully carried out with balloons designed and made by the method. It has been shown that the limit of the resisting pressure differential for a new designed balloon is same as that of a normal lobed-pumpkin balloon.

  11. Stability of Balloon-Retention Gastrostomy Tubes with Different Concentrations of Contrast Material: In Vitro Study

    International Nuclear Information System (INIS)

    Lopera, Jorge E.; Alvarez, Alex; Trimmer, Clayton; Josephs, Shellie; Anderson, Matthew; Dolmatch, Bart

    2009-01-01

    The purpose of this study was to determine the performance of two balloon-retention-type gastrostomy tubes when the balloons are inflated with two types of contrast materials at different concentrations. Two commonly used balloon-retention-type tubes (MIC and Tri-Funnel) were inflated to the manufacturer's recommended volumes (4 and 20 cm 3 , respectively) with normal saline or normal saline plus different concentrations of contrast material. Five tubes of each brand were inflated with normal saline and 0%, 25%, 50%, 75%, and 100% contrast material dilutions, using either nonionic hyperosmolar contrast, or nonionic iso-osmolar contrast. The tubes were submerged in a glass basin containing a solution with a pH of 4. Every week the tubes were visually inspected to determine the integrity of the balloons, and the diameter of the balloons was measured with a caliper. The tests were repeated every week for a total of 12 weeks. The MIC balloons deflated slightly faster over time than the Tri-Funnel balloons. The Tri-Funnel balloons remained relatively stable over the study period for the different concentrations of contrast materials. The deflation rates of the MIC balloons were proportionally related to the concentration of saline and inversely related to the concentration of the contrast material. At high contrast material concentrations, solidification of the balloons was observed. In conclusion, this in vitro study confirms that the use of diluted amounts of nonionic contrast materials is safe for inflating the balloons of two types of balloon-retention feeding tubes. High concentrations of contrast could result in solidification of the balloons and should be avoided.

  12. Transjugular balloon mitral valvotomy in a patient with severe kyphoscoliosis

    Directory of Open Access Journals (Sweden)

    George Joseph

    2016-09-01

    Full Text Available Balloon mitral valvotomy (BMV performed by the conventional transfemoral approach can be difficult or even impossible in the presence of structural impediments such as severe kyphoscoliosis, gross cardiac anatomic distortion and inferior vena caval anomalies. A 25-year-old woman with severe thoracolumbar kyphoscoliosis due to poliomyelitis presented with symptomatic rheumatic mitral valve stenosis. After the failure of transfemoral BMV, the procedure was attempted from the right jugular access, using a modified septal puncture technique. The left atrium was entered from the jugular access and the mitral valve was crossed and dilated successfully using over the wire balloon technique. Transjugular BMV is an effective alternative in patients with kyphoscoliotic spine that preclude transfemoral approach. The detailed technique used for the procedure, its advantages as well as the other percutaneous treatment options are also discussed.

  13. [Adherence and fidelity in patients treated with intragastric balloon].

    Science.gov (United States)

    Mazure, R A; Cancer, E; Martínez Olmos, M A; De Castro, M L; Abilés, V; Abilés, J; Bretón, I; Álvarez, V; Peláez, N; Culebras, J M

    2014-01-01

    A correct treatment of obesity needs a program of habits modification regardless of the selected technique, especially if it is minimally invasive as the intragastric balloon (BIG). The adherence of the obese patients with regard to recommended drugs measures to medium- and long-term is less than 50%. Given that the results obtained using the technique of gastric balloon must be seen influenced by adherence to the modification of habits program and its fulfillment, we reviewed series published in attention to the program proposed with the BIG. The series published to date provide few details about the used Therapeutic Programs as well as the adherence of patients to them, and even less concerning the Monitoring Plan and the loyalty of the patient can be seen. We conclude the convenience to agree on a follow-up strategy, at least the 6 months during which the BIG remain in the stomach.

  14. Observations of volcanic plumes using small balloon soundings

    Science.gov (United States)

    Voemel, H.

    2015-12-01

    Eruptions of volcanoes are very difficult to predict and for practical purposes may occur at any time. Any observing system intending to observe volcanic eruptions has to be ready at any time. Due to transport time scales, emissions of large volcanic eruptions, in particular injections into the stratosphere, may be detected at locations far from the volcano within days to weeks after the eruption. These emissions may be observed using small balloon soundings at dedicated sites. Here we present observations of particles of the Icelandic Grimsvotn eruption at the Meteorological Observatory Lindenberg, Germany in the months following the eruption and observations of opportunity of other volcanic particle events. We also present observations of the emissions of SO2 from the Turrialba volcano at San Jose, Costa Rica. We argue that dedicated sites for routine observations of the clean and perturbed atmosphere using small sounding balloons are an important element in the detection and quantification of emissions from future volcanic eruptions.

  15. Dosimetry of beta emitting radionuclides for use in balloon angioplasty

    International Nuclear Information System (INIS)

    Fox, R.A.

    1997-01-01

    The dose at varying distances from the surface of an infinite cylinder containing 90 Y, 32 P and 188 Re respectively is calculated using published scaled point dose kernels for these three radionuclides. It is shown that all are suitable radionuclides for use in the irradiation of arteries subsequent to balloon angioplasty. All three may be used as a radioactive liquid in the angioplasty balloon, thereby simplifying the procedure and enabling a uniform radiation dose to be given to the arterial wall. It is however shown that there is a rapid reduction in dose with distance from the arterial wall which demands careful specification of the prescribed radiation dose. A similar rapid reduction with distance is also found with a central radioactive wire or with a radioactive stent containing the same radionuclides. (author)

  16. Star camera aspect system suitable for use in balloon experiments

    International Nuclear Information System (INIS)

    Hunter, S.D.; Baker, R.G.

    1985-01-01

    A balloon-borne experiment containing a star camera aspect system was designed, built, and flown. This system was designed to provide offset corrections to the magnetometer and inclinometer readings used to control an azimuth and elevation pointed experiment. The camera is controlled by a microprocessor, including commendable exposure and noise rejection threshold, as well as formatting the data for telemetry to the ground. As a background program, the microprocessor runs the aspect program to analyze a fraction of the pictures taken so that aspect information and offset corrections are available to the experiment in near real time. The analysis consists of pattern recognition of the star field with a star catalog in ROM memory and a least squares calculation. The performance of this system in ground based tests is described. It is part of the NASA/GSFC High Energy Gamma-Ray Balloon Instrument (2)

  17. Accelerated partial breast irradiation utilizing balloon brachytherapy techniques

    International Nuclear Information System (INIS)

    Strauss, Jonathan B.; Dickler, Adam

    2009-01-01

    To overcome the barriers to BCT, methods of PBI in the setting of breast conservation have been explored. The method of PBI with the longest published follow-up is multi-catheter interstitial brachytherapy. Balloon-based brachytherapy with the MammoSite brachytherapy applicator was designed to simplify the brachytherapy procedure for PBI, enhance the reproducibility of the dosimetry, and improve patient comfort. The rates of local recurrence following PBI with the MammoSite applicator have been low, but there are few published reports and follow-up has been relatively short. The cosmetic outcomes and toxicity of MammoSite PBI are comparable to those seen after multicatheter-based PBI. Additional methods of balloon brachytherapy, including Xoft and SenoRx Contura have been developed. Finally, long-term follow-up after PBI is important for the welfare of individual patients and in order to establish the efficacy, late toxicity and cosmetic outcomes of this technique.

  18. Developing International Standards for Meteorological Balloon to Facilitate Industrial Progress

    Institute of Scientific and Technical Information of China (English)

    Deng Yizhi

    2011-01-01

    Meteorological balloon is made of natural rubber latex with a special process.On natural conditions,it carries the air sounding instrument into the high air to detect the meteorological elements in the air.As a means of delivery used in the aerological sounding,it is widely used in the meteorological,sailing,aeronautical,aerospace and other fields,and plays an extremely important role in the weather report,disaster prevention,disaster relief,guaranteeing ships and aircrafts to leave ports safely,and scientific research in relevant spaces,etc.Especially,the role of meteorological balloons is not ignorable in the forecast of extremely adverse weather frequently occurring around the world in recent years.

  19. Plasma heating by kinetic Alfven wave

    International Nuclear Information System (INIS)

    Assis, A.S. de.

    1982-01-01

    The heating of a nonuniform plasma (electron-ion) due to the resonant excitation of the shear Alfven wave in the low β regime is studied using initially the ideal MHD model and posteriorly using the kinetic model. The Vlasov equation for ions and the drift kinetic equation for electrons have been used. Through the ideal MHD model, it is concluded that the energy absorption is due to the continuous spectrum (phase mixing) which the shear Alfven wave has in a nonuniform plasma. An explicit expression for the energy absorption is derived. Through the kinetic model it is concluded that the energy absorption is due to a resonant mode convertion of the incident wave into the kinetic Alfven wave which propagates away from the resonant region. Its electron Landau damping has been observed. There has been a concordance with the MHD calculations. (Author) [pt

  20. On normal modes in classical Hamiltonian systems

    NARCIS (Netherlands)

    van Groesen, Embrecht W.C.

    1983-01-01

    Normal modes of Hamittonian systems that are even and of classical type are characterized as the critical points of a normalized kinetic energy functional on level sets of the potential energy functional. With the aid of this constrained variational formulation the existence of at least one family

  1. Advanced gamma ray balloon experiment ground checkout and data analysis

    Science.gov (United States)

    Blackstone, M.

    1976-01-01

    A software programming package to be used in the ground checkout and handling of data from the advanced gamma ray balloon experiment is described. The Operator's Manual permits someone unfamiliar with the inner workings of the software system (called LEO) to operate on the experimental data as it comes from the Pulse Code Modulation interface, converting it to a form for later analysis, and monitoring the program of an experiment. A Programmer's Manual is included.

  2. NEW APPROACHES: A hot air balloon from dustbin liners

    Science.gov (United States)

    Weaver, Nicholas

    1998-07-01

    This article describes how a simple hot air balloon, inflated by a hair dryer, can be made out of household bin liners and Sellotape. It can be used at sixth-form level as an application of the ideal gas equation, = constant, and is rather more exciting than heated pistons. It gives a taste of a simple engineering design process, although the students do have to be reasonably adept at geometry and algebra.

  3. Kinetic synergistic transitions in the Ostwald ripening processes

    Science.gov (United States)

    Sachkov, I. N.; Turygina, V. F.; Dolganov, A. N.

    2018-01-01

    There is proposed approach to mathematical description of the kinetic transitions in Ostwald ripening processes of volatile substance in nonuniformly heated porous materials. It is based upon the finite element method. There are implemented computer software. The main feature of the software is to calculate evaporation and condensation fluxes on the walls of a nonuniformly heated cylindrical capillary. Kinetic transitions are detected for three modes of volatile substances migration which are different by condensation zones location. There are controlling dimensionless parameters of the kinetic transition which are revealed during research. There is phase diagram of the Ostwald ripening process modes realization.

  4. Warm ion effects on kinetic drift cyclotron loss cone instabilities

    International Nuclear Information System (INIS)

    Guo Shichong; Shen Jiewu; Cai Shidong

    1988-01-01

    The effects of adding warm plasmas on the kinetic DCLC mode in high β loss cone plasmas are investigated in detail. It is found that when the fluid DCLC mode is stabilized by a small amount of warm plasma, the kinetic excitation still remains due to two different mechanisms, namely, (1) magnetic drift resonance dissipation excites the negative energy wave; (2) a new type of positive energy wave can become unstable as the resonance condition is met. Comparing with fluid approximation theory, more warm plasmas are needed to suppress the kinetic DCLC instabilities

  5. A Sensitivity Analysis of fMRI Balloon Model

    KAUST Repository

    Zayane, Chadia

    2015-04-22

    Functional magnetic resonance imaging (fMRI) allows the mapping of the brain activation through measurements of the Blood Oxygenation Level Dependent (BOLD) contrast. The characterization of the pathway from the input stimulus to the output BOLD signal requires the selection of an adequate hemodynamic model and the satisfaction of some specific conditions while conducting the experiment and calibrating the model. This paper, focuses on the identifiability of the Balloon hemodynamic model. By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement. Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space. In these studies, the identification was generally assessed using event-related paradigms. This paper justifies the reasons behind the need of adding knowledge, choosing certain paradigms, and completing the few existing identifiability studies through a global sensitivity analysis of the Balloon model in the case of blocked design experiment.

  6. Balloon Cell Urethral Melanoma: Differential Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    M. McComiskey

    2015-01-01

    Full Text Available Introduction. Primary malignant melanoma of the urethra is a rare tumour (0.2% of all melanomas that most commonly affects the meatus and distal urethra and is three times more common in women than men. Case. A 76-year-old lady presented with vaginal pain and discharge. On examination, a 4 cm mass was noted in the vagina and biopsy confirmed melanoma of a balloon type. Preoperative CT showed no distant metastases and an MRI scan of the pelvis demonstrated no associated lymphadenopathy. She underwent anterior exenterative surgery and vaginectomy also. Histology confirmed a urethral nodular malignant melanoma. Discussion. First-line treatment of melanoma is often surgical. Adjuvant treatment including chemotherapy, radiotherapy, or immunotherapy has also been reported. Even with aggressive management, malignant melanoma of the urogenital tract generally has a poor prognosis. Recurrence rates are high and the mean period between diagnosis and recurrence is 12.5 months. A 5-year survival rate of less than 20% has been reported in balloon cell melanomas along with nearly 20% developing local recurrence. Conclusion. To the best of our knowledge, this case is the first report of balloon cell melanoma arising in the urethra. The presentation and surgical management has been described and a literature review provided.

  7. Covered Balloon-Expanding Stents in Airway Stenosis.

    Science.gov (United States)

    Majid, Adnan; Kheir, Fayez; Chung, Jey; Alape, Daniel; Husta, Bryan; Oh, Scott; Folch, Erik

    2017-04-01

    The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (Pstent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.

  8. A Sensitivity Analysis of fMRI Balloon Model

    KAUST Repository

    Zayane, Chadia; Laleg-Kirati, Taous-Meriem

    2015-01-01

    Functional magnetic resonance imaging (fMRI) allows the mapping of the brain activation through measurements of the Blood Oxygenation Level Dependent (BOLD) contrast. The characterization of the pathway from the input stimulus to the output BOLD signal requires the selection of an adequate hemodynamic model and the satisfaction of some specific conditions while conducting the experiment and calibrating the model. This paper, focuses on the identifiability of the Balloon hemodynamic model. By identifiability, we mean the ability to estimate accurately the model parameters given the input and the output measurement. Previous studies of the Balloon model have somehow added knowledge either by choosing prior distributions for the parameters, freezing some of them, or looking for the solution as a projection on a natural basis of some vector space. In these studies, the identification was generally assessed using event-related paradigms. This paper justifies the reasons behind the need of adding knowledge, choosing certain paradigms, and completing the few existing identifiability studies through a global sensitivity analysis of the Balloon model in the case of blocked design experiment.

  9. Emergency medical support for a manned stratospheric balloon test program.

    Science.gov (United States)

    Blue, Rebecca S; Norton, Sean C; Law, Jennifer; Pattarini, James M; Antonsen, Erik L; Garbino, Alejandro; Clark, Jonathan B; Turney, Matthew W

    2014-10-01

    Red Bull Stratos was a commercial program that brought a test parachutist, protected by a full-pressure suit, in a stratospheric balloon with pressurized capsule to over 127,582 ft (38,969 m), from which he free fell and subsequently parachuted to the ground. Given that the major risks to the parachutist included ebullism, negative Gz (toe-to-head) acceleration exposure from an uncontrolled flat spin, and trauma, a comprehensive plan was developed to recover the parachutist under nominal conditions and to respond to any medical contingencies that might have arisen. In this report, the project medical team describes the experience of providing emergency medical support and crew recovery for the manned balloon flights of the program. The phases of flight, associated risks, and available resources were systematically evaluated. Six distinct phases of flight from an Emergency Medical Services (EMS) standpoint were identified. A Medical Support Plan was developed to address the risks associated with each phase, encompassing personnel, equipment, procedures, and communications. Despite geographical, communications, and resource limitations, the medical team was able to implement the Medical Support Plan, enabling multiple successful manned balloon flights to 71,615 ft (21,828 m), 97,221 ft (29,610 m), and 127,582 ft (38,969 m). The experience allowed refinement of the EMS and crew recovery procedures for each successive flight and could be applied to other high altitude or commercial space ventures.

  10. Balloon dilatation of nasopharyngeal stenosis in a dog.

    Science.gov (United States)

    Berent, Allyson C; Kinns, Jennifer; Weisse, Chick

    2006-08-01

    A dog was examined because of a 6-month history of upper airway stridor that began after postoperative regurgitation of gastric contents. Constant stridor was evident during inspiration and expiration, although it was worse during inspiration. The stridor was no longer evident when the dog's mouth was manually held open. Computed tomography, rhinoscopy, and fluoroscopy were used to confirm a diagnosis of nasopharyngeal stenosis. The dog was anesthetized, and balloon dilatation of the stenosis was performed. Prednisone was prescribed for 4 weeks after the procedure to decrease fibrous tissue formation. Although the dog was initially improved, signs recurred 3.5 weeks later, and balloon dilatation was repeated. This time, however, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Two months later, although the dog did not have clinical signs of stridor, a third dilatation procedure was performed because mild stenosis was seen on follow-up computed tomographic images; again, triamcinolone was injected into the area of stenosis at the end of the dilatation procedure. Three and 6 months after the third dilatation procedure, the dog reportedly was clinically normal. Findings suggest that balloon dilatation may be an effective treatment for nasopharyngeal stenosis in dogs.

  11. The Rocket Balloon (Rocketball): Applications to Science, Technology, and Education

    Science.gov (United States)

    Esper, Jaime

    2009-01-01

    Originally envisioned to study upper atmospheric phenomena, the Rocket Balloon system (or Rocketball for short) has utility in a range of applications, including sprite detection and in-situ measurements, near-space measurements and calibration correlation with orbital assets, hurricane observation and characterization, technology testing and validation, ground observation, and education. A salient feature includes the need to reach space and near-space within a critical time-frame and in adverse local meteorological conditions. It can also provide for the execution of technology validation and operational demonstrations at a fraction of the cost of a space flight. In particular, planetary entry probe proof-of-concepts can be examined. A typical Rocketball operational scenario consists of a sounding rocket launch and subsequent deployment of a balloon above a desired location. An obvious advantage of this combination is the additional mission 'hang-time' rendered by the balloon once the sounding rocket flight is completed. The system leverages current and emergent technologies at the NASA Goddard Space Flight Center and other organizations.

  12. Isothermal pumping analysis for high-altitude tethered balloons.

    Science.gov (United States)

    Kuo, Kirsty A; Hunt, Hugh E M

    2015-06-01

    High-altitude tethered balloons have potential applications in communications, surveillance, meteorological observations and climate engineering. To maintain balloon buoyancy, power fuel cells and perturb atmospheric conditions, fluids could be pumped from ground level to altitude using the tether as a hose. This paper examines the pumping requirements of such a delivery system. Cases considered include delivery of hydrogen, sulfur dioxide (SO2) and powders as fluid-based slurries. Isothermal analysis is used to determine the variation of pressures and velocities along the pipe length. Results show that transport of small quantities of hydrogen to power fuel cells and maintain balloon buoyancy can be achieved at pressures and temperatures that are tolerable in terms of both the pipe strength and the current state of pumping technologies. To avoid solidification, transport of SO2 would require elevated temperatures that cannot be tolerated by the strength fibres in the pipe. While the use of particle-based slurries rather than SO2 for climate engineering can reduce the pipe size significantly, the pumping pressures are close to the maximum bursting pressure of the pipe.

  13. A method for sampling microbial aerosols using high altitude balloons.

    Science.gov (United States)

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Low Cost Balloon programme of Indian Centre for Space Physics

    Science.gov (United States)

    Chakrabarti, Sandip Kumar

    2016-07-01

    Indian Centre for Space Physics has launched 89 Missions to near space using single or multiple weather balloons or very light plastic balloons. Basic goal was to capitalize miniaturization of equipments in modern ages. Our typical payload of less than 4kg weight consists of GPS, video camera, cosmic ray detectors, Attitude measurement unit, sunsensor and most importantly a 50-100sqcm X-ray/Gamma-ray detector (usually a scintillator type). The main purpose of the latter is to study spectra of secondary cosmic ray spectra (till our ceiling altitude of 36-42km) over the years and their seasonal variation or variation with solar cycle. We also study solar X-ray spectra, especially of solar flares. We have detected a Gamma Ray Burst (GRB) and pulsars. Our observation of black hole candidates did not yield satisfactory result yet mainly because of poor collimation (~ 10 deg x 10 deg) by lead collimator which introduces strong background also. Our effort with multiple balloon flights enabled us to have long duration flights. We believe that our procedure is very futuristic and yet at an affordable cost.

  15. Global assimilation of X Project Loon stratospheric balloon observations

    Science.gov (United States)

    Coy, L.; Schoeberl, M. R.; Pawson, S.; Candido, S.; Carver, R. W.

    2017-12-01

    Project Loon has an overall goal of providing worldwide internet coverage using a network of long-duration super-pressure balloons. Beginning in 2013, Loon has launched over 1600 balloons from multiple tropical and middle latitude locations. These GPS tracked balloon trajectories provide lower stratospheric wind information over the oceans and remote land areas where traditional radiosonde soundings are sparse, thus providing unique coverage of lower stratospheric winds. To fully investigate these Loon winds we: 1) compare the Loon winds to winds produced by a global data assimilation system (DAS: NASA GEOS) and 2) assimilate the Loon winds into the same comprehensive DAS. Results show that in middle latitudes the Loon winds and DAS winds agree well and assimilating the Loon winds have only a small impact on short-term forecasting of the Loon winds, however, in the tropics the loon winds and DAS winds often disagree substantially (8 m/s or more in magnitude) and in these cases assimilating the loon winds significantly improves the forecast of the loon winds. By highlighting cases where the Loon and DAS winds differ, these results can lead to improved understanding of stratospheric winds, especially in the tropics.

  16. Precision Attitude Control for the BETTII Balloon-Borne Interferometer

    Science.gov (United States)

    Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen

    2012-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.

  17. Cesium removal and kinetics equilibrium: Precipitation kinetics

    International Nuclear Information System (INIS)

    Barnes, M.J.

    1999-01-01

    This task consisted of both non-radioactive and radioactive (tracer) tests examining the influence of potentially significant variables on cesium tetraphenylborate precipitation kinetics. The work investigated the time required to reach cesium decontamination and the conditions that affect the cesium precipitation kinetics

  18. Ideal MHD stability properties of pressure-driven modes in low shear tokamaks

    International Nuclear Information System (INIS)

    Manickam, J.; Pomphrey, N.; Todd, A.M.M.

    1987-03-01

    The role of shear in determining the ideal MHD stability properties of tokamaks is discussed. In particular, we assess the effects of low shear within the plasma upon pressure-driven modes. The standard ballooning theory is shown to break down, as the shear is reduced and the growth rate is shown to be an oscillatory function of n, the toroidal mode number, treated as a continuous parameter. The oscillations are shown to depend on both the pressure and safety-factor profiles. When the shear is sufficiently weak, the oscillations can result in bands of unstable n values which are present even when the standard ballooning theory predicts complete stability. These instabilities are named ''infernal modes.'' The occurrence of these instabilities at integer n is shown to be a sensitive function of q-axis, raising the possibility of a sharp onset as plasma parameters evolve. 20 refs., 31 figs

  19. Field-theoretic calculation of kinetic helicity flux

    Indian Academy of Sciences (India)

    Given all these practical aspects, kinetic helicity is an important quantity to study in fluid turbulence. Turbulence involves millions of interacting modes. It is very difficult to analyze these modes theoretically as well as numerically. In recent times, a new numeri- cal procedure called 'large eddy simulations' (LES) has become ...

  20. Development of radioactive 166Ho-coated balloon and its dose estimation

    International Nuclear Information System (INIS)

    Park, K. B.; Kim, K. H.; Hong, Y. D.; Park, E. W.

    2000-01-01

    The use of balloon with radioisotope is a promising method to prevent restenosis after transluminal coronary arterial angioplasty or stent implantation. In this study, we have developed a new radioactive coated balloon, which is prepared by coating the surface of existing balloon with 166 Ho instead of being filled with beta sources which emit high energy beta-particles for the purpose of the delivery of sufficient radiation to the vessel wall. To estimate the safety of 166 Ho-coated balloon, leaching test and radiation resistance test of the balloon were performed. The absorbed dose distributions around the 166 Ho-coated balloon were estimated by means of Monte Carlo simulation and the initial activities for optimal therapeutic regimen were determined on the basis of this results

  1. Experimental investigation of undesired stable equilibria in pumpkin shape super-pressure balloon designs

    Science.gov (United States)

    Schur, W. W.

    2004-01-01

    Excess in skin material of a pneumatic envelope beyond what is required for minimum enclosure of a gas bubble is a necessary but by no means sufficient condition for the existence of multiple equilibrium configurations for that pneumatic envelope. The very design of structurally efficient super-pressure balloons of the pumpkin shape type requires such excess. Undesired stable equilibria in pumpkin shape balloons have been observed on experimental pumpkin shape balloons. These configurations contain regions with stress levels far higher than those predicted for the cyclically symmetric design configuration under maximum pressurization. Successful designs of pumpkin shape super-pressure balloons do not allow such undesired stable equilibria under full pressurization. This work documents efforts made so far and describes efforts still underway by the National Aeronautics and Space Administration's Balloon Program Office to arrive on guidance on the design of pumpkin shape super-pressure balloons that guarantee full and proper deployment.

  2. Plasma kinetic theory

    International Nuclear Information System (INIS)

    Elliott, J.A.

    1993-01-01

    Plasma kinetic theory is discussed and a comparison made with the kinetic theory of gases. The plasma is described by a modified set of fluid equations and it is shown how these fluid equations can be derived. (UK)

  3. Planetary Balloon-Based Science Platform Evaluation and Program Implementation

    Science.gov (United States)

    Dankanich, John W.; Kremic, Tibor; Hibbitts, Karl; Young, Eliot F.; Landis, Rob

    2016-01-01

    This report describes a study evaluating the potential for a balloon-based optical telescope as a planetary science asset to achieve decadal class science. The study considered potential science achievable and science traceability relative to the most recent planetary science decadal survey, potential platform features, and demonstration flights in the evaluation process. Science Potential and Benefits: This study confirms the cost the-benefit value for planetary science purposes. Forty-four (44) important questions of the decadal survey are at least partially addressable through balloon based capabilities. Planetary science through balloon observations can provide significant science through observations in the 300 nm to 5 m range and at longer wavelengths as well. Additionally, balloon missions have demonstrated the ability to progress from concept to observation to publication much faster than a space mission increasing the speed of science return. Planetary science from a balloon-borne platform is a relatively low-cost approach to new science measurements. This is particularly relevant within a cost-constrained planetary science budget. Repeated flights further reduce the cost of the per unit science data. Such flights offer observing time at a very competitive cost. Another advantage for planetary scientists is that a dedicated asset could provide significant new viewing opportunities not possible from the ground and allow unprecedented access to observations that cannot be realized with the time allocation pressures faced by current observing assets. In addition, flight systems that have a relatively short life cycle and where hardware is generally recovered, are excellent opportunities to train early career scientists, engineers, and project managers. The fact that balloon-borne payloads, unlike space missions, are generally recovered offers an excellent tool to test and mature instruments and other space craft systems. Desired Gondola Features: Potential

  4. Anchoring barbs and balloon expandable stents: what is the risk of perforation and failed stent deployment?

    Science.gov (United States)

    Bown, M J; Harrison, G J; How, T V; Brennan, J A; Fisher, R K; Vallabhaneni, S R; McWilliams, R G

    2012-09-01

    Balloon expandable stents may on occasion be deployed in close proximity to the anchoring barbs of endovascular grafts. The aim of this study was to determine the risk and effect of balloon perforation by anchoring barbs and to assess whether these risks are different if the balloon is protected by a covered stent mounted upon it. A bench-top model was developed to mimic the penetration of anchoring barbs into the lumen of medium sized blood vessels. The model allowed variation of angle and depth of vessel penetration. Both bare balloons and those with covered stents mounted upon them were tested in the model to determine whether there was a risk of perforation and which factors increased or decreased this risk. All combinations of barb angle and depth caused balloon perforation but this was most marked when the barb was placed perpendicular to the long axis of the balloon. When the deployment of covered stents was attempted balloon perforation occurred in some cases but full stent deployment was achieved in all cases where the perforation was in the portion of the balloon covered by the stent. The only situation in which stent deployment failed was where the barb was intentionally placed in the uncovered portion of the balloon. This resulted in only partial deployment of the stent. Balloon rupture is a distinct possibility when deploying balloon-expandable stents in close proximity to anchoring barbs. Care should be taken in this circumstance to ensure that the barb is well away from the uncovered portion of the balloon. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  5. Intra-aortic balloon shape change: effects on volume displacement during inflation and deflation.

    Science.gov (United States)

    Khir, Ashraf William; Bruti, Gianpaolo

    2013-07-01

    It has been observed that operating the intra-aortic balloon at an angle to the horizontal resulted in a reduction of the volume displaced toward the coronary arteries and compromised afterload reduction. Therefore, the aim of this work is to examine whether changing the current balloon shape, which has not been altered for 40 years, could compensate for the negative hemodynamic effects due to angulation. We tested two tapered balloons, increasing diameter (TID) and decreasing diameter (TDD), and compared the results with those obtained from a standard cylindrical balloon. The balloons were tested in vitro at 60 beats/min and a static pressure of 90 mm Hg. The balloons were operated at four angles (0°, 20°, 30°, 45°), and the pressure at three locations along the balloon (base, middle, and tip) was also measured. Flow rate upstream of the tip of the balloon was also measured to indicate the flow displaced toward the coronary circulation. The relative volume displaced toward (VUTVi) and suctioned away from (VUTVd) the simulated ascending aorta, during inflation and deflation, respectively, is reduced when a standard cylindrical balloon is operated at an angle to the horizontal. The TDD provided the greatest VUTVi and also produced the largest pulse pressure during deflation. Although the TID provided less VUTVi and VUTVd at smaller angles, it was not markedly affected by the change of angle. According to these results, different balloon shapes analyzed, with comparable volume to that of a cylindrical balloon, produced greater inflation and deflation benefits, at the horizontal and at a range of angles to the horizontal. Further investigations are required to optimize the shape of the tapered balloons to fit into the available physiological space. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  6. Use of Cutting Balloon in the Treatment of Urethral Stricture: A Novel Technique

    International Nuclear Information System (INIS)

    Yildirim, Erkan; Cicek, Tufan; Istanbulluoglu, Okan; Ozturk, Bulent

    2009-01-01

    The peripheral cutting balloon has been used to treat various nonvascular strictures as well as vascular stenosis. In this article, we describe for the first time the use of the cutting balloon in the treatment of patients with urethral stricture. Four patients with bulbar urethral stricture were included in the study. All strictures were successfully dilated with the cutting balloon, and patients were free of symptoms at 6-month follow-up. Cutting-balloon dilatation is a safe, easy-to-perform, and effective treatment for patients with tight urethral strictures.

  7. Cutting-balloon angioplasty of resistant ureteral stenosis as bridge to stent insertion

    Energy Technology Data Exchange (ETDEWEB)

    Iezzi, R., E-mail: iezzir@virgilio.it [Department of Bioimaging and Radiological Sciences, Institute of Radiology, ' A. Gemelli' Hospital - Catholic University, L.go A Gemelli 8, 00168 Rome (Italy); Di Stasi, C.; Simeone, A.; Bonomo, L. [Department of Bioimaging and Radiological Sciences, Institute of Radiology, ' A. Gemelli' Hospital - Catholic University, L.go A Gemelli 8, 00168 Rome (Italy)

    2011-07-15

    Ureteral stenting is a routine, minimally invasive procedure performed for relief of benign or malignant obstruction. In case of ureteral stenosis, to allow a correct insertion of the stent, a predilatation of the ureter stenosis with a conventional balloon catheter can be necessary. In exceptional cases, it can be difficult to advance an 7-8 Fr JJ-catheter over a tight resistant ureter stenosis following unsuccessful high-pressure balloon dilatation. In the present report, we describe two cases of resistant ureter stenosis successfully dilated by a cutting-balloon following the failure of high-pressure balloon dilatation, allowing a correct and uncomplicated antegrade stent insertion.

  8. Cutting-balloon angioplasty of resistant ureteral stenosis as bridge to stent insertion

    International Nuclear Information System (INIS)

    Iezzi, R.; Di Stasi, C.; Simeone, A.; Bonomo, L.

    2011-01-01

    Ureteral stenting is a routine, minimally invasive procedure performed for relief of benign or malignant obstruction. In case of ureteral stenosis, to allow a correct insertion of the stent, a predilatation of the ureter stenosis with a conventional balloon catheter can be necessary. In exceptional cases, it can be difficult to advance an 7-8 Fr JJ-catheter over a tight resistant ureter stenosis following unsuccessful high-pressure balloon dilatation. In the present report, we describe two cases of resistant ureter stenosis successfully dilated by a cutting-balloon following the failure of high-pressure balloon dilatation, allowing a correct and uncomplicated antegrade stent insertion.

  9. Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

    International Nuclear Information System (INIS)

    He, Xu; Shin, Ji Hoon; Kim, Hyo Cheol; Woo, Cheol Woong; Woo, Sung Ha; Choi, Won Chan; Kim, Jong Gyu; Lim, Jin Oh; Kim, Tae Hyung; Yoon, Chang Jin; Song, Ho Young; Kang, Wee Chang

    2005-01-01

    We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group II was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms (ρ < 0.001). A significant difference was also found between group III and IV for both phantoms (ρ < 0.001). The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body

  10. Safety and effectiveness of gastric balloons associated with hypocaloric diet for the treatment of obesity.

    Science.gov (United States)

    de Castro, Maria Luisa; Morales, Maria Jose; Martínez-Olmos, Miguel A; Pineda, Juan R; Cid, Lucia; Estévez, Pamela; del-Campo, Victor; Rodríguez-Prada, J Ignacio

    2013-10-01

    intragastric balloons provide early satiety and thereby induce short-term weight loss. The aim of this study was to evaluate safety and short and medium-term effectiveness of gastric balloons associated to hypocaloric diet in obesity. from May 2004 to June 2011 91 obese patients, body mass index (BMI) 45.2 +/- 7.2 kg/m2 were prospectively followed after endoscopic implantation of a gastric balloon associated to restricted diet. Successful therapy was defined as percent loss of total weight (%LTW) > or = 5 % at six months after balloon placement and 6 and 12 months after their withdrawal. All analyses followed intention-to treat principles considering significant p-values or = 5 %. Short-term and medium-term effectiveness was negatively associated to obesity in first-grade relatives (p = 0.003 and p = 0.04). Higher weight loss 6 months after balloon placement independently predicted medium-term effectiveness (p = 0.0001). Mortality was absent but there were two spontaneous deflations of air-filled balloons and severe withdrawal difficulties in 8 patients, leading to surgery in one case. Retrieval complications associated to air-filled balloons (p = 0.0005). in obesity, effectiveness of gastric balloons associated to hypocaloric diet decreases over time.Complications occurred mainly in the retrieval endoscopic procedure and related to air-filled balloons.

  11. Design and evaluation of a continuum robot with extendable balloons

    Directory of Open Access Journals (Sweden)

    E. Y. Yarbasi

    2018-02-01

    Full Text Available This article presents the design and preliminary evaluation of a novel continuum robot actuated by two extendable balloons. Extendable balloons are utilized as the actuation mechanism of the robot, and they are attached to the tip from their slack sections. These balloons can extend very much in length without having a significant change in diameter. Employing two balloons in an axially extendable, radially rigid flexible shaft, radial strain becomes constricted, allowing high elongation. As inflated, the balloons apply a force on the wall of the tip, pushing it forward. This force enables the robot to move forward. The air is supplied to the balloons by an air compressor and its flow rate to each balloon can be independently controlled. Changing the air volumes differently in each balloon, when they are radially constricted, orients the robot, allowing navigation. Elongation and force generation capabilities and pressure data are measured for different balloons during inflation and deflation. Afterward, the robot is subjected to open field and maze-like environment navigation tests. The contribution of this study is the introduction of a novel actuation mechanism for soft robots to have extreme elongation (2000 % in order to be navigated in substantially long and narrow environments.

  12. Usefulness of cutting balloon angioplasty for the treatment of congenital heart defects.

    Science.gov (United States)

    Kusa, Jacek; Mazurak, Magdalena; Skierska, Agnieszka; Szydlowski, Leslaw; Czesniewicz, Pawel; Manka, Lukasz

    2018-01-01

    Patients with complex congenital heart defects may have different hemodynamic prob-lems which require a variety of interventional procedures including angioplasty which involves using high-pressure balloons. After failure of conventional balloon angioplasty, cutting balloon angioplasty is the next treatment option available. The purpose of this study was to evaluate the safety and efficacy of cutting balloon angioplasty in children with different types of congenital heart defects. Cutting balloon angioplasty was performed in 28 children with different congenital heart defects. The indication for cutting balloon angioplasty was: pulmonary artery stenosis in 17 patients, creating or dilatation of interatrial communication in 10 patients, and stenosis of left subclavian artery in 1 patient. In the pulmonary arteries group there was a significant decrease in systolic blood pressure (SBP) in the proximal part of the artery from the average 74.33 ± 20.4 mm Hg to 55 ± 16.7 mm Hg (p cutting balloon angioplasty was performed after an unsuccessful classic Rashkind procedure. After cutting balloon angioplasty there was a significant widening of the interatrial communication. Cutting balloon angioplasty is a feasible and effective treatment option in different con-genital heart defects.

  13. Kinetic inductance detectors for far-infrared spectroscopy

    International Nuclear Information System (INIS)

    Barlis, A.; Aguirre, J.; Stevenson, T.

    2016-01-01

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

  14. Kinetic inductance detectors for far-infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barlis, A., E-mail: abarlis@physics.upenn.edu [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Aguirre, J. [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Stevenson, T. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)

    2016-07-11

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

  15. Thromboembolic events associated with single balloon-, double balloon-, and stent-assisted coil embolization of asymptomatic unruptured cerebral aneurysms: evaluation with diffusion-weighted MR imaging

    International Nuclear Information System (INIS)

    Takigawa, Tomoji; Suzuki, Kensuke; Sugiura, Yoshiki; Suzuki, Ryotaro; Takano, Issei; Shimizu, Nobuyuki; Tanaka, Yoshihiro; Hyodo, Akio

    2014-01-01

    The introduction of the balloon remodeling and stent-assisted technique has revolutionized the approach to coil embolization for wide-neck aneurysms. The purpose of this study was to determine the frequency of thromboembolic events associated with single balloon-assisted, double balloon-assisted, and stent-assisted coil embolization for asymptomatic unruptured aneurysms. A retrospective review was undertaken by 119 patients undergoing coiling with an adjunctive technique for unruptured saccular aneurysms (64 single balloon, 12 double balloon, 43 stent assisted). All underwent diffusion-weighted imaging (DWI) within 24 h after the procedure. DWI showed hyperintense lesions in 48 (40 %) patients, and ten (21 %) of these patients incurred neurological deterioration (permanent, two; transient, eight). Hyperintense lesions were detected significantly more often in procedures with the double balloon-assisted technique (7/12, 58 %) than with the single balloon-assisted technique (16/64, 25 %, p = 0.05). Occurrence of new lesions was significantly higher with the use of stent-assisted technique (25/43, 58 %) than with the single balloon-assisted technique (p = 0.001). Symptomatic ischemic rates were similar between the three groups. The increased number of microcatheters was significantly related to the DWI abnormalities (two microcatheters, 15/63 (23.8 %); three microcatheters, 20/41 (48.8 %) (p = 0.008); four microcatheters, 12/15 (80 %) (p = 0.001)). Thromboembolic events detected on DWI related to coil embolization for unruptured aneurysms are relatively common, especially in association with the double balloon-assisted and stent-assisted techniques. Furthermore, the number of microcatheters is highly correlated with DWI abnormalities. The high rate of thromboembolic events suggests the need for evaluation of platelet reactivity and the addition or change of antiplatelet agents. (orig.)

  16. Physics of resistive wall modes

    International Nuclear Information System (INIS)

    Igochine, V.

    2012-01-01

    The advanced tokamak regime is a promising candidate for steady-state tokamak operation which is desirable for a fusion reactor. This regime is characterized by a high bootstrap current fraction and a flat or reversed safety factor profile, which leads to operation close to the pressure limit. At this limit, an external kink mode becomes unstable. This external kink is converted into the slowly growing resistive wall mode (RWM) by the presence of a conducting wall. Reduction of the growth rate allows one to act on the mode and to stabilize it. There are two main factors which determine the stability of the RWM. The first factor comes from external magnetic perturbations (error fields, resistive wall, feedback coils, etc). This part of RWM physics is the same for tokamaks and reversed field pinch configurations. The physics of this interaction is relatively well understood and based on classical electrodynamics. The second ingredient of RWM physics is the interaction of the mode with plasma flow and fast particles. These interactions are particularly important for tokamaks, which have higher plasma flow and stronger trapped particle effects. The influence of the fast particles will also be increasingly more important in ITER and DEMO which will have a large fraction of fusion born alpha particles. These interactions have kinetic origins which make the computations challenging since not only particles influence the mode, but also the mode acts on the particles. Correct prediction of the ‘plasma–RWM’ interaction is an important ingredient which has to be combined with external field's influence (resistive wall, error fields and feedback) to make reliable predictions for RWM behaviour in tokamaks. All these issues are reviewed in this paper. (special topic)

  17. Active stabilization of n=0 and n=1 modes in the TCV tokamak

    International Nuclear Information System (INIS)

    Hofmann, F.; Tonetti, G.; Ward, D.J.; Gribov, Yu.

    1991-04-01

    The limits of operation of an elongated tokamak are generally defined by axisymmetric (n=0), free-boundary n=1, and ballooning modes. While it has become common practice to stabilize n=0 modes by a combination of passive and active systems, very few experiments have been done so far to investigate active stabilization of n=1 modes. In this paper, we discuss the possibilities for acitive stabilization of n=0 and n=1 in the TCV tokamak. (author) 2 figs., 2 tabs., 10 refs

  18. Fasting and meal-induced CCK and PP secretion following intragastric balloon treatment for obesity.

    Science.gov (United States)

    Mathus-Vliegen, Elisabeth M H; de Groot, Gerrit H

    2013-05-01

    Satiety is centrally and peripherally mediated by gastrointestinal peptides and the vagal nerve. We aimed to investigate whether intragastric balloon treatment affects satiety through effects on fasting and meal-stimulated cholecystokinin (CCK) and pancreatic polypeptide (PP) secretion. Patients referred for obesity treatment were randomised to 13 weeks of sham treatment followed by 13 weeks of balloon treatment (group 1; sham/balloon) or to twice a 13-week period of balloon treatment (group 2; balloon/balloon). Blood samples were taken for fasting and meal-stimulated CCK and PP levels at the start (T0) and after 13 (T1) and 26 (T2) weeks. Patients filled out visual analogue scales (VAS) to assess satiety. Forty-two patients (35 females, body weight 125.1 kg, BMI 43.3 kg/m(2)) participated. In group 1, basal CCK levels decreased but meal-stimulated response remained unchanged after 13 weeks of sham treatment. In group 2, basal and meal-stimulated CCK levels decreased after 13 weeks of balloon treatment. At the end of the second 13-week period, when group 1 had their first balloon treatment, they duplicated the initial 13-week results of group 2, whereas group 2 continued their balloon treatment and reduced meal-stimulated CCK release. Both groups showed reduced meal-stimulated PP secretions at T1 and T2 compared to T0. Changes in diet composition and VAS scores were similar. Improvements in glucose homeostasis partly explained the PP results. The reduced CCK and PP secretion after balloon positioning was unexpected and may reflect delayed gastric emptying induced by the balloon. Improved glucose metabolism partly explained the reduced PP secretion. Satiety and weight loss were not adversely influenced by these hormonal changes.

  19. Complex Coronary Interventions with the Novel Mozec™ CTO Balloon: The MOZART Registry.

    Science.gov (United States)

    Lupi, Alessandro; Rognoni, Andrea; Schaffer, Alon; Secco, Gioel G; Bongo, Angelo S

    2015-01-01

    Mozec™ CTO is a novel semicompliant rapid-exchange PTCA balloon catheter with specific features dedicated to treat complex coronary lesions like chronic total occlusions (CTOs). However, no data have been reported about the performance of this device in an all-comers population with complex coronary lesions. We evaluated the safety and success rate of Mozec™ CTO balloon in 41 consecutive patients with chronic stable angina and complex coronary lesions (15 severe calcified coronary stenoses, 15 bifurcation lesions with planned two-stent intervention, and 11 CTOs). Safety was assessed reporting the balloon burst rate after inflation exceeding the rated burst pressure (RBP) according to the manufacturer's reference table. Success was defined as the possibility to advance the device further the target lesion. The Mozec™ CTO balloon showed an excellent performance with a 93.3% success in crossing tight and severely calcified lesions (14/15 pts), a 93.3% success in engaging jailed side branches after stent deployment across bifurcations (14/15 pts), and a 90.9% success in crossing CTO lesions (10/11 pts). The burst rate at RBP of the Mozec™ CTO balloon was 6.7% (1/15 balloons) in the tight and severely calcified lesions, 6.7% (1/15 balloons) when dilating jailed vessels, and 9.1% (1/11 balloons) in CTOs. The novel Mozec™ CTO balloon dilatation catheter showed promising results when employed to treat complex lesions in an all-comers population. Further studies should clarify if this kind of balloon might reduce the need of more costly devices like over-the-wire balloons and microcatheters for complex lesions treatment.

  20. Operator's Manual for SHEBA Powered Tether Balloon System

    Science.gov (United States)

    Lappen, Cara-Lyn; Randall, David A.

    1998-01-01

    The Surface Heat and Energy Budget of the Arctic (SHEBA) was an intensive field project which took place in the Arctic Ocean from October 1997 through October 1998. Its purpose was to measure as many facets of the Arctic environment as possible so that we would be able to better understand the interaction between the ice, atmosphere, and ocean and their interactions with global climate. One aspect of the atmospheric field component was launching tethered balloons to monitor the profiles of temperature, wind, pressure, and humidity, as well as examine the vertical structure of cloud droplet sizes and distributions. The tethered balloon that we used was one specially designed for use in freezing climates by SPEC Corporation in Boulder, Colorado. A special winch that was able to withstand Arctic temperature and weather became necessary when the testing of simple winch systems used in warmer climates failed under these extreme conditions. The purpose of this manual is to acquaint any new user to the powered tethered balloon system deployed at the The Surface Heat and Energy Budget of the Arctic (SHEBA ice camp. It includes a description of the preparations necessary to get ready for a launch, the mechanics of the actual launch, and an account of the proper procedure for taking down the equipment when finished. It will also include tips on how to minimize potential equipment failures, some trouble shooting, and some safety ideas. This manual is designed so that new operators can use the system with minimal previous training. At the end of this manual, the reader will find a quick checklist.