WorldWideScience

Sample records for ballooning instability

  1. 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.

  2. Ballooning mode instability at the plasmapause

    Science.gov (United States)

    Lakhina, G. S.; Mond, M.; Hameiri, E.

    1990-01-01

    The ballooning mode instability, which can excite hydromagnetic waves at the plasmapause, is studied in the presence of azimuthal plasma flows induced during geomagnetically disturbed periods. A general sufficient criterion for the ballooning mode stability is derived, for a change in the potential energy greater than or equal to 0, which involves the integration over an entire field line. A local stability analysis at the equatorial plasmapause region shows that the ballooning modes could be spontaneously generated via instability under at least two conditions: one is similar to the usual interchange condition, and the second to the quasi-interchange modes. Both of these local instability conditions can be derived from the general stability criterion. Finally an exact solution for the equilibrium state with flow is derived analytically, and the change in the potential energy is computed numerically. It is found that, in the cases studied, the flow does not spontaneously excite the ballooning modes; it only further stabilizes (or destabilizes) the ballooning spectrum if originally the system is stable (or unstable). The analysis would be useful for the interpretation of some of the low-frequency modes observed at the ground and near the equatorial plasmapause.

  3. 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.

  4. Dynamic electromechanical instability of a dielectric elastomer balloon

    Science.gov (United States)

    Chen, Feifei; Zhu, Jian; Wang, Michael Yu

    2015-11-01

    Electromechanical instability, a significant phenomenon in dielectric elastomers, has been well studied in the literature. However, most previous work was based on the assumption that dielectric elastomers undergo quasi-static deformation. This letter investigates the dynamic electromechanical instability of a dielectric elastomer balloon which renders four types of oscillation subject to a parametric combination of DC and AC voltages. The simulated oscillations show that dynamic electromechanical instability occurs within quite a large range of excitation frequency, in the form of snap-through or snap-back, when the DC and AC voltages reach critical values. The balloon is at its most susceptible to dynamic electromechanical instability when the superharmonic, harmonic or subharmonic resonance is excited. Taking all excitation parameters into account, this letter analyzes the global critical condition which triggers the dynamic electromechanical instability of the balloon.

  5. Tokamak resistive magnetohydrodynamic ballooning instability in the negative shear regime

    Institute of Scientific and Technical Information of China (English)

    Shi Bing-Ren; Lin Jian-Long; Li Ji-Quan

    2007-01-01

    Improved confinement of tokamak plasma with central negative shear is checked against the resistive ballooning mode. In the negative shear regime, the plasma is always unstable for purely growing resistive ballooning mode. For a simplest tokamak equilibrium model, the s-α model, characteristics of this kind of instability are fully clarified by numerically solving the high n resistive magnetohydrodynamic ballooning eigen-equation. Dependences of the growth rate on the resistivity, the absolute shear value, the pressure gradient are scanned in detail. It is found that the growth rate is a monotonically increasing function of a while it is not sensitive to the changes of the shear s, the initial phase θ0 and the resistivity parameter εR.

  6. Kinetic Ballooning Instability as a Substorm Onset Mechanism

    International Nuclear Information System (INIS)

    A new scenario of substorm onset and current disruption and the corresponding physical processes are presented based on the AMPTE/CCE spacecraft observation and a kinetic ballooning instability theory. During the growth phase of substorms the plasma beta is larger than unity (20 greater than or equal to beta greater than or equal to 1). Toward the end of the late growth phase the plasma beta increases from 20 to greater than or equal to 50 in approximately 3 minutes and a low-frequency instability with a wave period of 50 - 75 sec is excited and grows exponentially to a large amplitude at the current disruption onset. At the onset, higher-frequency instabilities are excited so that the plasma and electromagnetic field form a turbulent state. Plasma transport takes place to modify the ambient pressure profile so that the ambient magnetic field recovers from a tail-like geometry to a dipole-like geometry. A kinetic ballooning instability (KBI) theory is proposed to explain the low-frequency instability (frequency and growth rate) and its observed high beta threshold (beta subscript c is greater than or equal to 50). Based on the ideal-MHD theory beta subscript c, superscript MHD approximately equals 1 and the ballooning modes are predicted to be unstable during the growth phase, which is inconsistent with observation that no appreciable magnetic field fluctuation is observed. The enhancement beta subscript c over beta subscript c, superscript MHD is due to the kinetic effects of trapped electrons and finite ion-Larmor radii which provide a large stabilizing effect by producing a large parallel electric field and hence a parallel current that greatly enhances the stabilizing effect of field line tension. As a result, beta subscript c is greatly increased over beta subscript c, superscript MHD by a factor proportional to the ratio of the total electron density to the untrapped electron density (n subscript e divided by n subscript eu) which is greater than or equal to

  7. Ballooning instability of the earth's plasma sheet region in the presence of parallel flow

    Science.gov (United States)

    Lakhina, G. S.; Hameiri, E.; Mond, M.

    1990-01-01

    Stability of the plasma sheet and plasma sheet boundary layer against the ballooning mode instability is investigated. The equilibrium state of a two-dimensional plasma sheet configuration with parallel sheared flow is modeled. This equilibrium is shown to be ballooning unstable when delta-W is not positive definite, where delta-W is the potential energy. The eigenmode structure of the ballooning mode is found by imposing the boundary conditions that the waves are totally reflected from the ionosphere, and that no waves are coming in from infinity. The eigenmode structure of the unstable balloning modes is highly oscillatory, extending beyond about 100 R(E). The ballooning modes are thus a possible candidate for explaining the MHD waves and other dynamical events observed in the magnetotail by ISEE 3 and other spacecraft.

  8. The stability of the near-Earth magnetotail against the ballooning instability

    Science.gov (United States)

    Ohtani, Shin-Ichi; Tamao, Tsutomu

    1992-01-01

    In an extension to a previous study, conditions for the ballooning instability in the magnetohydrodynamic approximation are derived. It is necessary for exciting the ballooning instability that the plasma pressure is higher where plasma is convected outward. However, the expansion of plasma, which results from the divergence of outward flows in the curved geometry of field lines, may overcompensate for the convective change in the plasma pressure. Conditions for the instability are derived from the equation describing the linear coupling between the Alfven and slow magnetosonic waves. The result indicates that excessive curvature stabilizes, rather than destabilizes, perturbations, as well as the field aligned current and the field aligned flow. That is the field line curvature should be smaller than the pressure gradient for exciting the ballooning instability. It is inferred that this condition is not satisfied during quiet times in the near Earth tail. The plasma sheet becomes more stable to the instability in accordance with the thinning of the plasma sheets during the growth phase of substorms, while in the region nearer to the Earth (the inner edge of the plasma sheet or the ring current region) the plasma pressure gradient, which is possibly localized during the growth phase, may drive the instability.

  9. Does the ballooning instability trigger substorms in the near-Earth magnetotail?

    Science.gov (United States)

    Ohtani, Shin-Ichi; Tamao, Tsutomu

    1993-01-01

    The stability of the near-Earth magnetotail against ballooning (or configurational) instability is examined in the framework of the MHD approximation. It is emphasized that a change in plasma pressure induced by a meriodional electric field drift delta u(sub n) is an important factor that determines the stability. We have to consider two ways in which plasma pressure changes, that is, a convective change -delta u(sub n) grad(P(sub 0)), where P(sub 0) is background plasma pressure, and plasma expansion/compression -P(sub 0) dive (delta u(sub n)). Since delta u(sub n) is perpendicular to the magnetic field and its magnitude is inversely proportional to the magnetic field strength, delta u(sub n) diverges/converges in usual tail magnetic field configurations. For the instability, the convective change must overwhelm the effects of the plasma expansion/compression. However, near the equator in the near-Earth tail, the latter may overcompensate for the former. We describe the ballooning instability in terms of a coupling between the Alfven and slow magnetosonic waves in an inhomogeneous plasma and derive instability conditions. The result shows that the excessive curvature stabilizes, rather than destabilizes, perturbations. It is also found that the field-aligned flow stabilizes perturbations, as well as the field-aligned current. We infer that under quiet conditions, the plasma pressure gradient in the near-Earth tail is not sharp enough to trigger the instability. The plasma sheet is expected to become more stable during the substorm growth phase because of an increase in the field line curvature associated with the plasma sheet thinning. In the region closer to the Earth, including the ring current, the plasma pressure gradient may be localized in a limited range of the radial distance during the growth phase. However, recently reported plasma and magnetic field parameters before substorm onsets do not provide very convincing evidence that the ballooning instability

  10. Conditions for the validity of the incompressible assumption for the ballooning instability in the long-thin magnetospheric equilibrium

    OpenAIRE

    Miura, Akira

    2000-01-01

    Conditions under which the compressibility can be neglected for the magnetospheric ballooning instability, which arises in the shear Alfvén branch, are clarified in the context of ideal magnetohydrodynamic plasmas and stochastic plasmas by using the normal mode analysis and the energy principle. An expansion in the small parameter, which is equal to the ratio of the ∇⊥ B 0 scale length to the field line curvature radius, shows that the incompressible assumption is valid for the ballooning ins...

  11. Effects of drifts and ballooning instability on the divertor in–out asymmetry in EAST tokamak

    International Nuclear Information System (INIS)

    The divertor in–out asymmetry (DIOA) of the disconnected double null (DDN) configuration with the active X-point at the bottom in EAST has been investigated using the SOLPS code package to explore its forming mechanism. Effects of classical drifts and ballooning-like transport (BLT) instability are evaluated individually and compared to the DIOA during H-mode. The results show that the BLT plays a much larger role in forming the DIOA. It is further found that the combined effects of the classical drifts and BLT can account for the formation of the DIOA observed experimentally in EAST. In addition, the results also imply that reversing the toroidal magnetic field may be used to mitigate the EAST DIOA under certain circumstances

  12. Effects of drifts and ballooning instability on the divertor in–out asymmetry in EAST tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Du, Hailong [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Sang, Chaofeng, E-mail: sang@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Wang, L., E-mail: lwang@ipp.ac.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Bonnin, X. [LSPM-CNRS, Université Paris 13, Sorbonne Paris Cité, 99 avenue J.-B. Clément, Villetaneuse F-93430 (France); Guo, H.Y. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Sun, Jizhong [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Wang, Dezhen, E-mail: wangdez@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2015-08-15

    The divertor in–out asymmetry (DIOA) of the disconnected double null (DDN) configuration with the active X-point at the bottom in EAST has been investigated using the SOLPS code package to explore its forming mechanism. Effects of classical drifts and ballooning-like transport (BLT) instability are evaluated individually and compared to the DIOA during H-mode. The results show that the BLT plays a much larger role in forming the DIOA. It is further found that the combined effects of the classical drifts and BLT can account for the formation of the DIOA observed experimentally in EAST. In addition, the results also imply that reversing the toroidal magnetic field may be used to mitigate the EAST DIOA under certain circumstances.

  13. Bursting water balloons

    CERN Document Server

    Lund, Hugh M

    2011-01-01

    The impact and rupture of water-filled balloons upon a flat, rigid surface is studied experimentally, for which three distinct stages of the flow are observed. Due to the impact, waves are formed on the balloon's surface for which the restoring force is tension in the latex. Immediately following rupture of the membrane, a shear instability created by the retraction of the balloon is observed. At later times, a larger-scale growth of the interfacial amplitude is observed, that may be regarded as a manifestation of a phenomenon known as the Richtmyer-Meshkov instability. This flow is closely related to the classical understanding of the Richtmyer-Meshkov instability for when there exists a density difference between the fluids inside and outside the balloon. Further, it is shown experimentally that this growth of the interface may also occur when there is no density difference across the balloon, a situation that does not arise for the standard Richtmyer-Meshkov instability.

  14. 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.

  15. Magneto-Hydrodynamic High-n Ballooning Mode Instability of an Analytic Axi-Symmetric Toroidal Equilibrium with Arbitrary Aspect Ratio

    Institute of Scientific and Technical Information of China (English)

    SHI Bing-Ren; LI Ji-Quan

    2007-01-01

    An exact ballooning mode eigen-equation is derived to study stability of axi-symmetric toroidal plasma with arbitrary aspect ratio, including the tokamak, the finite aspect ratio and the spherical torus plasmas. For comparison with the widely used ( s - α) model, an analytic exact equilibrium configuration with circular magnetic surfaces is analysed in detail. It is indicated that the (s - α) model needs to be improved for more realistic configurations.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Balloon Design Software

    Science.gov (United States)

    Farley, Rodger

    2007-01-01

    PlanetaryBalloon Version 5.0 is a software package for the design of meridionally lobed planetary balloons. It operates in a Windows environment, and programming was done in Visual Basic 6. By including the effects of circular lobes with load tapes, skin mass, hoop and meridional stress, and elasticity in the structural elements, a more accurate balloon shape of practical construction can be determined as well as the room-temperature cut pattern for the gore shapes. The computer algorithm is formulated for sizing meridionally lobed balloons for any generalized atmosphere or planet. This also covers zero-pressure, over-pressure, and super-pressure balloons. Low circumferential loads with meridionally reinforced load tapes will produce shapes close to what are known as the "natural shape." The software allows for the design of constant angle, constant radius, or constant hoop stress balloons. It uses the desired payload capacity for given atmospheric conditions and determines the required volume, allowing users to design exactly to their requirements. The formulations are generalized to use any lift gas (or mixture of gases), any atmosphere, or any planet as described by the local acceleration of gravity. PlanetaryBalloon software has a comprehensive user manual that covers features ranging from, but not limited to, buoyancy and super-pressure, convenient design equations, shape formulation, and orthotropic stress/strain.

  1. Validity of the fluid description of critical β and Alfvén time scale of ballooning instability onset in the near-Earth collisionless high-β plasma

    OpenAIRE

    Miura, Akira

    2004-01-01

    For a realistic, highly stretched, two-dimensional tail configuration, in which the pressure gradient force is balanced with the curved field line tension force at the equator, the growth rates and the real frequencies of the ideal magnetohydrodynamic (MHD) and two component fluid (nonideal MHD) ballooning modes, in which the phrase “two component fluid” means that the Hall and the electron pressure gradient terms are included in the generalized Ohm's law, the ion bounce frequency ω bi , the ...

  2. The Descending Helium Balloon

    Science.gov (United States)

    Helseth, Lars Egil

    2014-01-01

    I describe a simple and fascinating experiment wherein helium leaks out of a rubber balloon, thereby causing it to descend. An estimate of the volumetric leakage rate is made by measuring its rate of descent.

  3. Universal stratospheric balloon gradiometer

    Science.gov (United States)

    Tsvetkov, Yury; Filippov, Sergey; Brekhov, Oleg; Nikolaev, Nikolay

    The study of the interior structure of the Earth and laws of its evolution is one of the most difficult problems of natural science. Among the geophysical fields the anomaly magnetic field is one of the most informational in questions of the Earth’s crust structure. Many important parameters of an environment are expedient for measuring at lower altitudes, than satellite ones. So, one of the alternatives is stratospheric balloon survey. The balloon flight altitudes cover the range from 20 to 50 km. At such altitudes there are steady zone air flows due to which the balloon flight trajectories can be of any direction, including round-the-world (round-the-pole). For investigation of Earth's magnetic field one of the examples of such sounding system have been designed, developed and maintained at IZMIRAN and MAI during already about 25 years. This system consists of three instrumental containers uniformly placed along a vertical 6 km line. Up today this set has been used only for geomagnetic purposes. So we describe this system on example of the measuring of the geomagnetic field gradient. System allows measuring a module and vertical gradient of the geomagnetic field along the whole flight trajectory and so one’s name is - stratospheric balloon magnetic gradiometer (SMBG). The GPS-receivers, located in each instrumental container, fix the flight coordinates to within several tens meters. Process of SBMG deployment, feature of the exit of rope from the magazine at the moment of balloon launching has been studied. Used magazine is cellular type. The hodograph of the measuring base of SBMG and the technique of correction of the deviations of the measuring base from the vertical line (introduction of the amendments for the deviation) during the flight have been investigated. It is shown that estimation of the normal level of values of the vertical gradient of the geomagnetic field is determined by the accuracy of determining the length of the measuring base SBMG

  4. Mars Solar Balloon Lander Project

    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...

  5. Venus Altitude Cycling Balloon Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ISTAR Group ( IG) and team mate Thin Red Line Aerospace (TRLA) propose a Venus altitude cycling balloon (Venus ACB), an innovative superpressure balloon...

  6. JACEE long duration balloon flights

    International Nuclear Information System (INIS)

    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

  7. Breakthrough in Mars balloon technology

    Science.gov (United States)

    Kerzhanovich, V. V.; Cutts, J. A.; Cooper, H. W.; Hall, J. L.; McDonald, B. A.; Pauken, M. T.; White, C. V.; Yavrouian, A. H.; Castano, A.; Cathey, H. M.; Fairbrother, D. A.; Smith, I. S.; Shreves, C. M.; Lachenmeier, T.; Rainwater, E.; Smith, M.

    2004-01-01

    Two prototypes of Mars superpressure balloons were flight tested for aerial deployment and inflation in the Earth's stratosphere in June, 2002. One was an 11.3 m diameter by 6.8 m high pumpkin balloon constructed from polyethylene film and Zylon (PBO) tendons, the second was a 10 m diameter spherical balloon constructed from 12 μm thick Mylar film. Aerial deployment and inflation occurred under parachute descent at 34 km altitude, mimicing the dynamic pressure environment expected during an actual Mars balloon mission. Two on-board video cameras were used on each flight to provide real-time upward and downward views of the flight train. Atmospheric pressure and temperature were also recorded. Both prototypes successfully deployed from their storage container during parachute descent at approximately 40 m/s. The pumpkin balloon also successfully inflated with a 440 g charge of helium gas injected over a 1.5-min period. Since the helium inflation system was deliberately retained after inflation in this test, the pumpkin balloon continued to fall to the ocean where it was recovered for post-flight analysis. The less robust spherical balloon achieved only a partial (~70%) inflation before a structural failure occurred in the balloon film resulting in the loss of the vehicle. This structural failure was diagnosed to result from the vigorous oscillatory motion of the partially inflated balloon, possibly compounded by contact between the balloon film and an instrumentation box above it on the flight train. These two flights together represent significant progress in the development of Mars superpressure balloon technology and pave the way for future flight tests that will include post-deployment flight of the prototype balloons at a stable altitude.

  8. Titan Balloon Convection Model Project

    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...

  9. Buddy balloon for TAVI.

    Science.gov (United States)

    Balkin, Jonathan; Silberman, Shuli; Almagor, Yaron

    2013-11-15

    Percutaneous transfemoral aortic valve replacement is a new rapidly evolving technique that has made significant progress in recent years. The technology is however limitted and in some cases has resulted in failure to deliver the prosthetic valve. We describe a new technique using a buddy balloon, from the contralateral femoral artery, to assist in crossing the native aortic valve in those cases where extreme calcification and or tortuosity have caused the delivery system to hang up on the aortic wall. The technique is easily applied and facilitates the success of the procedure in cases which may otherwise have to be converted to open surgical aortic valve replacement.

  10. A Methane Balloon Inflation Chamber

    Science.gov (United States)

    Czerwinski, Curtis J.; Cordes, Tanya J.; Franek, Joe

    2005-01-01

    The various equipments, procedure and hazards in constructing the device for inflating a methane balloon using a standard methane outlet in a laboratory are described. This device is fast, safe, inexpensive, and easy to use as compared to a hydrogen gas cylinder for inflating balloons.

  11. Nationwide Eclipse Ballooning Project

    Science.gov (United States)

    Colman Des Jardins, Angela; Berk Knighton, W.; Larimer, Randal; Mayer-Gawlik, Shane; Fowler, Jennifer; Harmon, Christina; Koehler, Christopher; Guzik, Gregory; Flaten, James; Nolby, Caitlin; Granger, Douglas; Stewart, Michael

    2016-05-01

    The purpose of the Nationwide Eclipse Ballooning Project is to make the most of the 2017 rare eclipse event in four main areas: public engagement, workforce development, partnership development, and science. The Project is focused on two efforts, both student-led: online live video of the eclipse from the edge of space and the study of the atmospheric response to the eclipse. These efforts, however, involving more than 60 teams across the US, are challenging in many ways. Therefore, the Project is leveraging the NASA Space Grant and NOAA atmospheric science communities to make it a success. The first and primary topic of this poster is the NASA Space Grant supported online live video effort. College and high school students on 48 teams from 31 states will conduct high altitude balloon flights from 15-20 locations across the 8/21/2017 total eclipse path, sending live video and images from near space to a national website. Video and images of a total solar eclipse from near space are fascinating and rare. It’s never been done live and certainly not in a network of coverage across a continent. In addition to the live video to the web, these teams are engaged in several other science experiments as secondary payloads. We also briefly highlight the eclipse atmospheric science effort, where about a dozen teams will launch over one hundred radiosondes from across the 2017 path, recording an unprecedented atmospheric data sample. Collected data will include temperature, density, wind, humidity, and ozone measurements.

  12. Spectrum of the ballooning Schroedinger equation

    International Nuclear Information System (INIS)

    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 θk 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 θk

  13. 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...

  14. Shoulder Instability

    Science.gov (United States)

    ... Risk Factors Is shoulder instability the same as shoulder dislocation? No. The signs of dislocation and instability might ... the same to you--weakness and pain. However, dislocation occurs when your shoulder goes completely out of place. The shoulder ligaments ...

  15. Superpressure Tow Balloon for Extending Durations and Modifying Trajectories of High Altitude Balloon Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation involves the concept of using a Superpressure Tow Balloon (STB) with existing NASA high altitude balloon designs to form a tandem balloon...

  16. Shoulder instability

    International Nuclear Information System (INIS)

    In the shoulder, the advantages of range of motion are traded for the disadvantages of vulnerability to injury and the development of instability. Shoulder instability and the lesion it produces represent one of the main causes of shoulder discomfort and pain. Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to their causative factors as the pathogenesis of instability plays an important role with respect to treatment options: instabilities are classified in traumatic and atraumatic instabilities as part of a multidirectional instability syndrome, and in microtraumatic instabilities. Plain radiographs ('trauma series') are performed to document shoulder dislocation and its successful reposition. Direct MR arthrography is the most important imaging modality for delineation the different injury patterns on the labral-ligamentous complex and bony structures. Monocontrast CT-arthrography with use of multidetector CT scanners may be an alternative imaging modality, however, regarding the younger patient age, MR imaging should be preferred in the diagnostic work-up of shoulder instabilities. (orig.)

  17. BLOCKING SUN WITH ORBITING BALLOONS

    Energy Technology Data Exchange (ETDEWEB)

    Chul Park [Department of Aerospace Engineering, Kor ea Advanced Institute of Science and Technology, Daejeon (Korea)

    2008-09-30

    Sun's radiation power reaching Earth's surface can be reduced by letting large balloons circle the Earth in orbits at approximately 1000 km altitude. These balloons, made of plastic films 1 mm in thickness, of a diameter of approximately 46 km, will weigh about 10,000 tons each. A balloon will consist of one hundred of 100 ton pieces. They are transported to the orbit piece by piece, and are assembled there into the spherical shape. They are kept inflated with the vapor pressure of potassium and the electrostatic forces. The inclination angles of these balloons with respect to the solar ecliptic plane can be varied from zero to 90 degrees, although efficiency is highest with the zero degree inclination. If zero degree inclination is chosen, twenty-three of these will reduce the average sun's radiation by 0.01%. In the 1000 km orbits, which are stable and are populated only by space debris, these balloons will serve also to remove the debris.

  18. Sensor System for Super-Pressure Balloon Performance Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Long-duration balloon flights are an exciting new area of scientific ballooning, enabled by the development of large super-pressure balloons. As these balloons...

  19. Hip instability.

    Science.gov (United States)

    Smith, Matthew V; Sekiya, Jon K

    2010-06-01

    Hip instability is becoming a more commonly recognized source of pain and disability in patients. Traumatic causes of hip instability are often clear. Appropriate treatment includes immediate reduction, early surgery for acetabular rim fractures greater than 25% or incarcerated fragments in the joint, and close follow-up to monitor for avascular necrosis. Late surgical intervention may be necessary for residual symptomatic hip instability. Atraumatic causes of hip instability include repetitive external rotation with axial loading, generalized ligamentous laxity, and collagen disorders like Ehlers-Danlos. Symptoms caused by atraumatic hip instability often have an insidious onset. Patients may have a wide array of hip symptoms while demonstrating only subtle findings suggestive of capsular laxity. Traction views of the affected hip can be helpful in diagnosing hip instability. Open and arthroscopic techniques can be used to treat capsular laxity. We describe an arthroscopic anterior hip capsular plication using a suture technique. PMID:20473129

  20. Balloon Exoplanet Nulling Interferometer (BENI)

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

    2009-01-01

    We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

  1. 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.

  2. Ballonnen in zee = balloons as marine litter

    NARCIS (Netherlands)

    Franeker, van J.A.

    2008-01-01

    Releasing balloons seems harmless. However, remains of balloons, especially valves and ribbons are becoming a common and persistent type of marine litter found on beaches. Following Dutch Queens day 2007, large numbers of Dutch balloons were found in Normandy, France. Animals may become entangled in

  3. Non-linear analysis and the design of Pumpkin Balloons: stress, stability and viscoelasticity

    Science.gov (United States)

    Rand, J. L.; Wakefield, D. S.

    Tensys have a long-established background in the shape generation and load analysis of architectural stressed membrane structures Founded upon their inTENS finite element analysis suite these activities have broadened to encompass lighter than air structures such as aerostats hybrid air-vehicles and stratospheric balloons Winzen Engineering couple many years of practical balloon design and fabrication experience with both academic and practical knowledge of the characterisation of the non-linear viscoelastic response of the polymeric films typically used for high-altitude scientific balloons Both companies have provided consulting services to the NASA Ultra Long Duration Balloon ULDB Program Early implementations of pumpkin balloons have shown problems of geometric instability characterised by improper deployment and these difficulties have been reproduced numerically using inTENS The solution lies in both the shapes of the membrane lobes and also the need to generate a biaxial stress field in order to mobilise in-plane shear stiffness Balloons undergo significant temperature and pressure variations in flight The different thermal characteristics between tendons and film can lead to significant meridional stress Fabrication tolerances can lead to significant local hoop stress concentrations particularly adjacent to the base and apex end fittings The non-linear viscoelastic response of the envelope film acts positively to help dissipate stress concentrations However creep over time may produce lobe geometry variations that may

  4. 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.

  5. Global electrodynamics from superpressure balloons

    Science.gov (United States)

    Holzworth, R. H.; Hu, H.

    1995-01-01

    Electric field and conductivity measurements in the stratosphere between November 1992 and March 1993 have been made using superpressure balloons in the southern hemisphere. Over 400 payload-days of data have been made during a record setting experiment called ELBBO (Extended Life Balloon Borne Observatories). This experiment resulted in 4 flights aloft simultaneously for over 2 months including one flight which lasted over 4 months. Electrodynamical coupling between the atmosphere and ionosphere is studied using the measured electric fields, and a simple empirical model of the stratospheric conductivity. Altitude profiles of conductivity have been obtained from several superpressure balloon flights using the large end-of-flight altitude swings on the last few days of each flight (as the balloon begins to loose superpressure). Coupling between the fields and atmospheric inertial waves has been observed. Effects and dynamics of the global circuit suggest that standard models are missing significant phenomena. Large scale ionospheric convection activity has been studied from the polar cap to the middle latitudes. Cusp latitude fields have been continuously measured for many days in a row.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, W.A. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1996-09-01

    It has been found that ideal ballooning modes can impose very restrictive volume average {beta} 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 {beta}* from 2% to 5%. (author) 3 figs., 10 refs.

  7. Collective instabilities

    Energy Technology Data Exchange (ETDEWEB)

    K.Y. Ng

    2003-08-25

    The lecture covers mainly Sections 2.VIII and 3.VII of the book ''Accelerator Physics'' by S.Y. Lee, plus mode-coupling instabilities and chromaticity-driven head-tail instability. Besides giving more detailed derivation of many equations, simple interpretations of many collective instabilities are included with the intention that the phenomena can be understood more easily without going into too much mathematics. The notations of Lee's book as well as the e{sup jwt} convention are followed.

  8. Baroclinic instabilities

    OpenAIRE

    Joly, Laurent; Chassaing, Patrick; Chapin, Vincent; Reinaud, Jean; Micallef, J; Suarez, Juan; Bretonnet, L

    2003-01-01

    1. Introduction - Illustrative examples from experiments and simulations 2. The baroclinic torque in high Froude number flows, its organization, scale and order of magnitude 3. Stability of the inhomogeneous mixing-layer 4. Transition of the inhomogeneous mixing-layer and the 2D secondary baroclinic instability 5. The strain field of 2D light jets 6. Transition to three-dimensionality in light jets and the question of side-jets 7. Baroclinic instability of heavy vortices and...

  9. Carpal instability

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, R.; Froehner, S.; Coblenz, G.; Christopoulos, G. [Institut fuer Diagnostische und Interventionelle Radiologie, Herz- und Gefaessklinik GmbH, Bad Neustadt an der Saale (Germany)

    2006-10-15

    This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads (''dyskinetics'') or suffers from abnormal motion of its bones during movement (''dyskinematics''). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being ''occult'' for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the handsurgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis. (orig.)

  10. Scientific ballooning in India: recent developments

    Science.gov (United States)

    Joshi, M. N.; Damle, S. V.

    The National Scientific Balloon Facility (NBF) of the Tata Institute of Fundamental Research (TIFR) has been conducting regular balloon flights for various experiments in the areas of Space Astronomy and Atmospheric Sciences. A continuous improvement in all aspects of Scientific Ballooning through a sustained R and D programme ensures uptodate services and a better handle on the design specifications for the balloon. Recent developments in balloon grade films, continuous improvements in design specifications, balloon manufacturing methods, flight operational procedures and improved balloon flight capabilities have resulted in a greatly improved flight performance in the last five years. A launch capability upgradation programme in terms of new launch spool and new launch vehicle has been initiated to be able to safely launch balloons with gross lifts upto 3500 kg, balloon volumes upto 450,000 m^3 and payloads upto 1400 kg. A series of steps have been initiated to improve long duration flight capabilities. In this paper, we present details on some of these aspects of Scientific Ballooning in India.

  11. A Mars 2011 Balloon Mission Trade Study

    Science.gov (United States)

    Smith, I.; Lew, T.; Perry, W.

    Mars Scouts are competitively selected PI-led missions to further Mars exploration in ways that satisfy NASA s overall objectives but are not currently in the planned line of missions The current 2006 Announcement of Opportunity AO for Mars Scouts has just closed The goal of this SwRI study was to develop a new balloon mission concept to where it could be credibly proposed for the AO The balloon system was defined in the study as consisting of two parts the balloon flight system BFS and the balloon deployment inflation system DIS The BFS includes the balloon envelope accessory hardware and gondola The balloon includes the envelope seams end fittings load core inflation tube diffusers payload tether shock attenuator and separation hardware The DIS includes the balloon container deployment hardware sequencer tankage gas and control hardware Trade studies were performed to better define the mission design space These studies included 1 effect of varied atmospheric thermal loads 2 effect of varying latitudes 3 effect of payload mass for varying altitudes 4 effect of radiative material properties on balloon size mass 5 effect of material areal densities on balloon size mass and 6 effect of inflation gas on system masses Results of the balloon trade study for the Mars 2011 mission opportunity will be presented

  12. 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.

  13. Shoulder instability

    International Nuclear Information System (INIS)

    Shoulder instability is a common clinical feature leading to recurrent pain and limitated range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging. (orig.)

  14. Beam Instabilities

    CERN Document Server

    Rumolo, G

    2014-01-01

    When a beam propagates in an accelerator, it interacts with both the external fields and the self-generated electromagnetic fields. If the latter are strong enough, the interplay between them and a perturbation in the beam distribution function can lead to an enhancement of the initial perturbation, resulting in what we call a beam instability. This unstable motion can be controlled with a feedback system, if available, or it grows, causing beam degradation and loss. Beam instabilities in particle accelerators have been studied and analysed in detail since the late 1950s. The subject owes its relevance to the fact that the onset of instabilities usually determines the performance of an accelerator. Understanding and suppressing the underlying sources and mechanisms is therefore the key to overcoming intensity limitations, thereby pushing forward the performance reach of a machine.

  15. Hyperspectral Polarimeter for Monitoring Balloon Strain Project

    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...

  16. Scientific Ballooning Activities and Recent Developments in Technology and Instrumentation of the TIFR Balloon Facility, Hyderabad

    Science.gov (United States)

    Buduru, Suneel Kumar

    2016-07-01

    The Balloon Facility of Tata Institute of Fundamental Research (TIFR-BF) is a unique center of expertise working throughout the year to design, fabricate and launch scientific balloons mainly for space astronomy, atmospheric science and engineering experiments. Recently TIFR-BF extended its support to new user scientists for conducting balloon launches for biological and middle atmospheric sciences. For the first time two balloon launches conducted for sending live lab rats to upper stratosphere and provided launch support for different balloon campaigns such as Tropical Tropopause Dynamics (TTD) to study water vapour content in upper tropospheric and lower stratospheric regions over Hyderabad and the other balloon campaign to study the Asian Tropopause Aerosol Layer (BATAL) during the Indian summer monsoon season. BATAL is the first campaign to conduct balloon launches during active (South-West) monsoon season using zero pressure balloons of different volumes. TIFR-BF also provided zero pressure and sounding balloon support to various research institutes and organizations in India and for several international space projects. In this paper, we present details on our increased capability of balloon fabrication for carrying heavier payloads, development of high strength balloon load tapes and recent developments of flight control and safety systems. A summary of the various flights conducted in two years will be presented along with the future ballooning plans.

  17. Numerical studies of edge localized instabilities in tokamaks

    International Nuclear Information System (INIS)

    A new computational tool, edge localized instabilities in tokamaks equilibria (ELITE), has been developed to help our understanding of short wavelength instabilities close to the edge of tokamak plasmas. Such instabilities may be responsible for the edge localized modes observed in high confinement H-mode regimes, which are a serious concern for next step tokamaks because of the high transient power loads which they can impose on divertor target plates. ELITE uses physical insight gained from analytic studies of peeling and ballooning modes to provide an efficient way of calculating the edge ideal magnetohydrodynamic stability properties of tokamaks. This paper describes the theoretical formalism which forms the basis for the code

  18. Recombination instability

    DEFF Research Database (Denmark)

    D'Angelo, N.

    1967-01-01

    A recombination instability is considered which may arise in a plasma if the temperature dependence of the volume recombination coefficient, alpha, is sufficiently strong. Two cases are analyzed: (a) a steady-state plasma produced in a neutral gas by X-rays or high energy electrons; and (b...

  19. Peeling-Ballooning Mode Analysis in Shifted-Circle Tokamak Equilibria

    Science.gov (United States)

    Burke, B.; Kruger, S. E.; Hegna, C. C.; Snyder, P. B.; Sovinec, C. R.; Zhu, P.

    2009-11-01

    Progress in understanding edge localized modes (ELMs) has been made by investigating the stability properties of edge localized peeling-ballooning modes. We focus on the evolution of ideal MHD modes over a large spectrum in two shifted-circle tokamak equilibria, using the extended-MHD code NIMROD. The TOQ-generated equilibria model a H-mode plasma with a pedestal pressure profile and parallel edge currents. A vacuum region is prescribed by a resistivity profile that transitions from a small to very large value at a specified location. The vacuum model is benchmarked against the linear ideal MHD codes ELITE & GATO. We demonstrate vacuum effects on the stability by adjusting the vacuum location relative to the pedestal pressure region. Ballooning-like instabilities dominate distant vacuum cases, whereas peeling mode physics is expected to dominate as the vacuum approaches the pedestal. Numerical simulations of the early nonlinear stages of edge localized MHD instabilities are presented. Comparisons between equilibria that have ``ballooning'' dominated instabilities relative to equilibria that are ``peeling'' dominated are made.

  20. Unified Description of Tokamak Ideal MHD Instabilities (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    石秉仁

    2002-01-01

    By using a coordinate system associated with magnetic surfaces, a unified eigen mode equation for describing the tokamak ideal MHD instabilities is derived in the shear-Alfven approximation. Based on this equation having a general operator form, the eigen-mode equation governing the large-scale perturbation (such as the kink mode, the low-n ballooning mode and the Alfven mode) and small-scale perturbation (such as the high-n ballooning mode, the local mode)can be further deduced. In the first part of the present study, the small-scale perturbation is discussed in detail.

  1. [Carpal instability].

    Science.gov (United States)

    Redeker, J; Vogt, P M

    2011-01-01

    Carpal instability can be understood as a disturbed anatomical alignment between bones articulating in the carpus. This disturbed balance occurs either only dynamically (with movement) under the effect of physiological force or even statically at rest. The most common cause of carpal instability is wrist trauma with rupture of the stabilizing ligaments and adaptive misalignment following fractures of the radius or carpus. Carpal collapse plays a special role in this mechanism due to non-healed fracture of the scaphoid bone. In addition degenerative inflammatory alterations, such as chondrocalcinosis or gout, more rarely aseptic bone necrosis of the lunate or scaphoid bones or misalignment due to deposition (Madelung deformity) can lead to wrist instability. Under increased pressure the misaligned joint surfaces lead to bone arrosion with secondary arthritis of the wrist. In order to arrest or slow down this irreversible process, diagnosis must occur as early as possible. Many surgical methods have been thought out to regain stability ranging from direct reconstruction of the damaged ligaments, through ligament replacement to partial stiffening of the wrist joint.

  2. Neutral beam effects on tokamak ballooning mode stability

    International Nuclear Information System (INIS)

    An equation is derived that gives a necessary, as well as sufficient, stability criterion for the guiding center plasma to instabilities of large toroidal mode number. It is found that quasi-perpendicular injection induces a displacement of the psub(perpendicular to) contours with respect to the flux surfaces away from the destabilizing curvature region, which enhances the stability of tensor pressure equilibria over comparable scalar pressure equilibria. Also found is a distinct difference between the necessary and sufficient stability limits when the most unstable modes concentrate in regions of relatively high pressure. Both stability criteria coalesce when ballooning modes, which appear near the edge of the plasma where the pressure is low, dominate. (author)

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

    Science.gov (United States)

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

    2000-05-01

    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.

  4. Reevaluation of the balloon in gastrointestinal manometry.

    Science.gov (United States)

    Wilkes, P R; Hoskin, R W; Semlacher, E A; MacCannell, K L; Tyberg, J V

    1994-09-01

    Although the flow-through catheter (FTC) system has been useful and satisfactorily accurate for gastrointestinal manometry, we hypothesized that a cylindrical, liquid-filled balloon would also accurately reflect stress imposed by a sphincter. Latex balloons were fitted over the side ports of a closed-end catheter. The responses of the balloon and FTC system were compared in a cylindrical chamber commonly identified as a Starling resistor. Independent, constant-pressure sources were used to control both the inwardly directed "contact pressure" of the Starling resistor (Ps) and the intraluminal fluid pressure (P(lum)). The balloon transducers responded linearly and accurately (slope = 1) to changes in both Ps and P(lum) within the test range (0-200 mmHg, 0-26.7 kPa). When either P(lum) or Ps was held constant and the other changed, the balloon transducers always accurately measured the higher of the two pressures. Although the performance of the FTC system was improved after the Starling resistor was lubricated, the FTC system sometimes responded inaccurately to changes in Ps. The ability of the balloon transducers to measure the contractions of the lower esophageal sphincter and of the esophagus was demonstrated. We conclude that the balloon transducer can measure sphincter pressure accurately and suggest that, in certain circumstances, it might be advantageous relative to the FTC system. PMID:7842396

  5. Airborne Internet Providing Tethered Balloon System

    Directory of Open Access Journals (Sweden)

    Suvriti Dhawan1

    2015-12-01

    Full Text Available In this paper we shall introduce a new system for providing wireless network communication over a specified area using ’lighter than air’ balloons. This technology will replace the existing fiber optic network system. This will be done by using a tethered balloon along with the payload (containing a receiver, a transmitter and a radio communication device.This payload will be suspended from the ground at an altitude (depending on the area of coverage required. Users under this area will be able to access this system directly for internet connectivity. This system can be used over large areas like universities, companies and societies to provide internet facility to their users through Wi-Fi or over an area where the user is specified (commercial purposes. Currently Google is working on similar idea called the ’Google Loon’ in which they use high altitude balloons which float at an altitude twice as high as air planes and the weather. They recently tested this system over New-Zealand by providing internet to their pilot testers on ground. Their balloons not being stationary, move with directional winds and have to be replaced one after the other to maintain consistency. This can be a huge problem over the areas where upper atmospheric winds are not in favorable direction. We can resolve this problem by using our stationary tethered balloon system which can communicate with the loon balloons to provide internet facility over a desired area. Moreover when our balloon will communicate with the loon balloon it will increase the coverage area as the loon balloon has to communicate to a point which is above the ground. Our system will not only replace the existing fiber optic system but it will also be selfsustaining i.e. It will generate its own power using solar panels.

  6. 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…

  7. Investigating Diffusion and Entropy with Carbon Dioxide-Filled Balloons

    Science.gov (United States)

    Jadrich, James; Bruxvoort, Crystal

    2010-01-01

    Fill an ordinary latex balloon with helium gas and you know what to expect. Over the next day or two the volume will decrease noticeably as helium escapes from the balloon. So what happens when a latex balloon is filled with carbon dioxide gas? Surprisingly, carbon dioxide balloons deflate at rates as much as an order of magnitude faster than…

  8. 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 ...

  9. Cutting Balloon angioplasty for cardiac transplant vasculopathy.

    OpenAIRE

    Takano, Y.; Currier, JW; Yeatman, LA; Kobashigawa, JA; Rogers, AD; Cianfichi, LJ; Fishbein, MC; Tobis, JM

    2002-01-01

    We performed Cutting Balloon angioplasty on 20 lesions in 11 heart transplant recipients 7.5 +/- 3.8 years after transplantation. The mean percentage of diameter stenosis decreased from 88.3% +/- 13.8% to 19.6% +/- 13.7% after Cutting Balloon angioplasty without complication. Seven patients underwent follow-up angiography at 4.9 +/- 1.7 months in a total of 12 lesions, and all lesions showed restenosis with a mean diameter stenosis of 84.4% +/- 19.2%. Cutting Balloon angioplasty can be used t...

  10. The balloon and the airship technological heritage

    Science.gov (United States)

    Mayer, N. J.

    1981-01-01

    The balloon and the airship are discussed with emphasis on the identification of commonalities and distinctions. The aerostat technology behind the shape and structure of the vehicles is reviewed, including a discussion of structural weight, internal pressure, buckling, and the development of a stable tethered balloon system. Proper materials for the envelope are considered, taking elongation and stress into account, and flight operation and future developments are reviewed. Airships and tethered balloons which are designed to carry high operating pressure with low gas loss characteristics are found to share similar problems in low speed flight operations, while possessing interchangeable technologies.

  11. Stratospheric electric field measurements with transmediterranean balloons

    Science.gov (United States)

    de La Morena, B. A.; Alberca, L. F.; Curto, J. J.; Holzworth, R. H.

    1993-01-01

    The horizontal component of the stratospheric electric field was measured using a balloon in the ODISEA Campaign of Transmediterranean Balloon Program. The balloon flew between Trapani (Sicily) and El Arenosillo (Huelva, Spain) along the 39 deg N parallel at a height between 34 and 24 km. The high values found for the field on fair-weather and its quasi-turbulent variation, both in amplitude and direction, are difficult to explain with the classical electric field source. A new source, first described by Holzworth (1989), is considered as possibly causing them.

  12. Recent Developments in Balloon Support Instrumentation at TIFR Balloon Facility, Hyderabad.

    Science.gov (United States)

    Vasudevan, Rajagopalan

    2012-07-01

    The Balloon Facility of Tata Institute of Fundamental Research has been conducting stratospheric balloon flights regularly for various experiments in Space Astronomy and Atmospheric Sciences. A continuous improvement in Balloon flight Support instrumentation by the Control Instrumentation Group to keep in space with the growing complexities of the scientific payloads have contributed to the total success of balloon flights conducted recently. Recent improvements in display of Balloon position during balloon flight by showing on real time the balloon GPS position against Google TM maps is of immense help in selecting the right spot for payload landing and safe recovery . For further speeding up the payload recovery process, a new GPS-GSM payload system has been developed which gives SMS of the payload position information to the recovery team on their cell phones. On parallel footing, a new GPS- VHF system has been developed using GPS and Radio Modems for Balloon Tracking and also for obtaining the payload impact point. On the Telecommand side, a single board Telecommand/ Timer weighing less than 2 Kg has been specially developed for use in the mesosphere balloon test flight. The interference on the existing Short Range Telemetry System has been eliminated by introducing a Band Pass Filter and LNA in the Receiving system of the modules, thereby enhancing its reliability. In this paper , we present the details of the above mentioned developments.

  13. Shielded Mars Balloon Launcher (SMBL) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences, along with its partner Vertigo Industries, proposes a novel approach to deployment of balloon-based payloads into the Martian atmosphere....

  14. Magnetometer for Balloons and UAVs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR project will investigate a new, low-cost approach to atomic magnetometry that is suited for operation from UAVs and research balloons. Atomic...

  15. Attitude determination for balloon-borne experiments

    CERN Document Server

    Gandilo, N N; Amiri, M; Angile, F E; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, H C; Contaldi, C R; Crill, B P; Devlin, M J; Dober, B; Dore, O P; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Fukui, Y; Galitzki, N; Gambrel, A E; Golwala, S; Gudmundsson, J E; Halpern, M; Hasselfield, M; Hilton, G C; Holmes, W A; Hristov, V V; Irwin, K D; Jones, W C; Kermish, Z D; Klein, J; Korotkov, A L; Kuo, C L; MacTavish, C J; Mason, P V; Matthews, T G; Megerian, K G; Moncelsi, L; Morford, T A; Mroczkowski, T K; Nagy, J M; Netterfield, C B; Novak, G; Nutter, D; O'Brient, R; Pascale, E; Poidevin, F; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Savini, G; Scott, D; Shariff, J A; Soler, J D; Thomas, N E; Trangsrud, A; Truch, M D; Tucker, C E; Tucker, G S; Tucker, R S; Turner, A D; Ward-Thompson, D; Weber, A C; Wiebe, D V; Young, E Y

    2014-01-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of SPIDER, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. ...

  16. Retrieving Balloon Data in Flight Project

    Data.gov (United States)

    National Aeronautics and Space Administration —   NASA has plans to fly stratospheric ULDBs for missions of 100 days or more in the next few years. As these balloons circumnavigate the globe multiple...

  17. Power Systems Design for Long Duration Ballooning

    Science.gov (United States)

    Stilwell, Bryan; Chuzel, Alain

    2016-01-01

    The Columbia Scientific Balloon Facility has been designing and building high-altitude balloon power systems for over 26 years. With that experience, we have found certain types of PV panels, batteries, and charge controllers that are reliable in stratospheric environments. The ultimate goal is to ensure that power systems will provide power reliably throughout the duration of an LDB flight. The purpose of this presentation is to provide some general guidelines and best practices for power system design.

  18. Test ventilation with smoke, bubbles, and balloons

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. New stent delivery balloon: a technical note.

    Science.gov (United States)

    di Mario, C; Reimers, B; Reinhardt, R; Ferraro, M; Moussa, I; Colombo, A

    1997-12-01

    This study reports the first clinical application of a new noncompliant balloon composed of a middle polyurethane layer sandwiched between an inner layer of polyethylene terephtalate and an outer membrane that provides for consistent even expansion. With this balloon design, the very low compliance and high pressure resistance of polyethylene terephthalate are associated with the high elasticity of polyurethane, preventing balloon damage from stent crimping and expansion and allowing a firm embedding of the stent struts. Palmaz-Schatz stent implantation was successful in 33/35 stents (94%), and the two stents that could not be advanced up to the lesion were successfully withdrawn. High pressure expansion of the stent was obtained during deployment with no balloon ruptures at inflation pressures equal or lower than 16 atmospheres (atm). Accurate positioning of the stent was facilitated by the two markers at the balloon ends and by the optimal visualization after contrast injection, even with 6 Fr guiding catheters. This new delivery system maintains the advantages of hand-crimped stents on noncompliant balloons, reducing the risk of stent loss. PMID:9408637

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

    International Nuclear Information System (INIS)

    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)

  1. The French Balloon Program 2013 - 2017

    Science.gov (United States)

    Dubourg, Vincent; Vargas, André; Raizonville, Philippe

    2016-07-01

    With over 50 years' experience in the field, the French Centre National d'Etudes Spatiales (CNES) goes on supporting - as designer and operator - a significant scientific ballooning program. In particular so because balloons still give a unique and valuable access to near space science. From 2008 to 2013, an important renovation effort was achieved, beginning by Zero Pressure Balloons (ZPB) systems, to comply with more stringent Safety constraints and to the growing reliability and performance requirements from scientific missions. The paper will give an overview of the CNES new capabilities and services for operational balloon activities, and their availability status. The scientific launch campaigns of the past two years will be presented. A focus will be made on the results of the Stratoscience 2015 flight campaign from Timmins, Ontario, using the NOSYCA command and control system for ZPB, qualified in flight in 2013. In particular, the PILOT telescope successfully flew during the 2015 campaign, key figures about the flight and mission will be given. An outlook of the new stratospheric long duration flight systems currently in process of developement at CNES will be given, as well as the presentation of the Stratéole 2 project, dedicated to the survey of the low stratosphere and upper troposphere in equatorial regions, with a fleet of small suprer pressure balloons (SPB). As far as tropospheric balloons are concerned, the Aeroclipper initiative will be presented, aiming at qualifying a quasi-tethered balloon, pushed by the winds close to the sea surface, for the study of cyclones. The scientific launch campaigns and the main payloads in the study for the near future will also be presented.

  2. Near ultraviolet spectrograph for balloon platform

    Science.gov (United States)

    Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    2015-06-01

    Small and compact scientific payloads may be easily designed constructed and own on high altitude balloons. Despite the fact that large orbital observatories provide accurate observations and statistical studies of remote and/or faint space sources, small telescopes on board balloons or rockets are still attractive because of their low cost and rapid response time. We describe here a near ultraviolet (NUV) spectrograph designed to be own on a high{altitude balloon platform. Our basic optical design is a modified Czerny-Turner system using off the shelf optics. We compare different methods of aberration corrections in such a system. We intend the system to be portable and scalable to different telescopes. The use of reflecting optics reduces the transmission loss in UV. We plan on using an image intensified CMOS sensor operating in photon counting mode as the detector of choice.

  3. 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......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...... York in Donald Barthelme's short story  "The Balloon" from 1968 is discussed in the light of the chapter's epistemological understanding of fantasy....

  4. High altitude balloon experiments at IIA

    Science.gov (United States)

    Nayak, Akshata; Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    Recent advances in balloon experiments as well as in electronics have made it possible to fly scientific payloads at costs accessible to university departments. We have begun a program of high altitude ballooning at the Indian Institute of Astrophysics, Bengaluru. The primary purpose of this activity is to test low-cost ultraviolet (UV) payloads for eventual space flight, but we will also try scientific exploration of the phenomena occurring in the upper atmosphere, including sprites and meteorite impacts. We present the results of the initial experiments carried out at the CREST campus of IIA, Hosakote, and describe our plans for the future.

  5. Cutting balloon angioplasty for intrastent restenosis treatment

    Directory of Open Access Journals (Sweden)

    João Orávio de Freitas Jr

    1999-05-01

    Full Text Available We describe here two patients with angiographic diagnosis of intrastent restenosis and regional myocardial ischemia. One stent restenosis was located in a native coronary artery and the other in a vein graft. Both were treated with cutting balloon angioplasty (CBA, inflated at low pressures. Angiographic success was obtained and both patients were discharged in the day after the procedure. Cutting balloon angioplasty using low inflation pressures achieved important luminal gains, in these two cases of intrastent restenosis. Further studies are necessary before the effectiveness of this procedure can be precisely defined.

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

    CERN Document Server

    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.

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

    International Nuclear Information System (INIS)

    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. 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...

  9. Auditory Risk of Exploding Hydrogen-Oxygen Balloons

    Science.gov (United States)

    Gee, Kent L.; Vernon, Julia A.; Macedone, Jeffrey H.

    2010-01-01

    Although hydrogen-oxygen balloon explosions are popular demonstrations, the acoustic impulse created poses a hearing damage risk if the peak level exceeds 140 dB at the listener's ear. The results of acoustical measurements of hydrogen-oxygen balloons of varying volume and oxygen content are described. It is shown that hydrogen balloons may be…

  10. Increased Production of Sonic Hedgehog by Ballooned Hepatocytes

    OpenAIRE

    Rangwala, Fatima; Cynthia D Guy; Lu, Jiuyi; SUZUKI, Ayako; Burchette, James L.; Abdelmalek, Manal F; Chen, Wei; Diehl, Anna Mae

    2011-01-01

    Ballooned hepatocytes distinguish nonalcoholic steatohepatitis (NASH) from steatosis. Such cells contain dilated endoplasmic reticulum and ubiquitin aggregates, characteristics of endoplasmic reticulum stress. Hepatocyte ballooning increases risk for fibrosis in NASH, suggesting ballooned hepatocytes release pro-fibrogenic factors. Hedgehog ligands function as pro-fibrogenic factors in liver diseases, but mechanisms for Hedgehog ligand production remain poorly understood. We evaluated the hyp...

  11. Single-balloon versus double-balloon bipedicular kyphoplasty for osteoporotic vertebral compression fractures.

    Science.gov (United States)

    Wang, Heng; Sun, Zhenzhong; Wang, Zhiwen; Jiang, Weimin

    2015-04-01

    Twenty-eight patients with osteoporotic vertebral compression fractures (OVCF) were treated with single-balloon bipedicular kyphoplasty (Group A), and 40 patients were treated with double-balloon bipedicular kyphoplasty (Group B). Visual Analogue Scale (VAS) score, vertebral height, and kyphotic angle (KA) were evaluated pre-operatively, post-operatively (3 days after surgery) and at final follow-up. Operative time, X-ray exposure frequency and costs were recorded. The mean operative time and X-ray exposure frequency in Group A were greater than in Group B (pkyphoplasty is a safe and cost-effective surgical method for the treatment of OVCF. It can achieve pain relief comparable with double-balloon bipedicular kyphoplasty. However, double-balloon bipedicular kyphoplasty is more efficacious in terms of the restoration of vertebral height and reduction of KA, and the operative time and X-ray exposure frequency are lower.

  12. Survey of balloon design problems and prospects for large super-pressure balloons in the next century

    Science.gov (United States)

    Yajima, Nobuyuki

    About a half century has passed since modern scientific ballooning started in the 1950's. All this while, size and payload capabilities of zero-pressure balloons have improved rapidly. On the other hand, a super-pressure balloon which can take the place of a conventional large zero-pressure balloon has not yet become operational. To investigate this problem, previous research on balloon design is surveyed. It is concluded that quite important design problems have been left unsolved. Problems occur when a load tape assembly is introduced to the natural shape balloon system. The author proposed a new balloon design concept, named 3-D gore design, at the last COSPAR held in Nagoya in 1998. This theory improves the conventional natural shape design concept for the balloon reinforced by load tapes. This new design concept enables enhancing the strength of a balloon dramatically. In addition, the strength does not depend on balloon size. This theory will accelerate the development of large super-pressure balloons which will play a leading role in scientific ballooning in the 21st century.

  13. Attitude determination for balloon-borne experiments

    Science.gov (United States)

    Gandilo, N. N.; Ade, P. A. R.; Amiri, M.; Angilè, F. E.; Benton, S. J.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Crill, B. P.; Devlin, M. J.; Dober, B.; Doré, O. P.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Fukui, Y.; Galitzki, N.; Gambrel, A. E.; Golwala, S.; Gudmundsson, J. E.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Holmes, W. A.; Hristov, V. V.; Irwin, K. D.; Jones, W. C.; Kermish, Z. D.; Klein, J.; Korotkov, A. L.; Kuo, C. L.; MacTavish, C. J.; Mason, P. V.; Matthews, T. G.; Megerian, K. G.; Moncelsi, L.; Morford, T. A.; Mroczkowski, T. K.; Nagy, J. M.; Netterfield, C. B.; Novak, G.; Nutter, D.; O'Brient, R.; Pascale, E.; Poidevin, F.; Rahlin, A. S.; Reintsema, C. D.; Ruhl, J. E.; Runyan, M. C.; Savini, G.; Scott, D.; Shariff, J. A.; Soler, J. D.; Thomas, N. E.; Trangsrud, A.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Tucker, R. S.; Turner, A. D.; Ward-Thompson, D.; Weber, A. C.; Wiebe, D. V.; Young, E. Y.

    2014-07-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of Spider, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of < 5' rms in-flight, and < 5" rms post-flight.

  14. Treatment of tuberculous bronchostenosis: balloon bronchoplasty

    International Nuclear Information System (INIS)

    The purpose of this study is to evaluate the efficacy of the balloon bronchoplasty in the treatment of the tuberculous bronchostenosis. Balloon bronchoplasty was performed in thirteen patients with stenosis of the left main bronchus (two with combined left upper and lower lobar bronchostenosis) using a inflatable balloon catheter under a fluoroscopic guide. We analysed the changes in the severity of dyspnea and wheezing, serial FEV1/FVC as a parameter of the airflow obstruction, and bronchial diameter and lung volume on chest radiographs. The extent of pulmonary tuberculosis was correlated with the improvement of FEV1/ FVC. There was an improvement of dyspnea in 69% (9/13), decrease of wheezing in 69% (9/13), significant increase of FEV1/FVC in 18% (2/11). The increase of the bronchial diameter and lung volume were seen in 84% (11/13) and 53% (7/13), respectively. The significant increase of FEV1/FVC was seen in 28% (2/7) of the patients with lung involvement of tuberculous less than one third of left upper lobe, whereas there was no increase in those of more than one third. The was no complication except transient leukocytosis, fever and blood-tinged sputum. In conclusion, balloon bronchoplasty is effective in the treatment of medically intractable tuberculous bronchostenosis, and can be considered as an initial method of treatment

  15. Measurements of gondola motion on a stratospheric balloon flight

    CERN Document Server

    Safonova, Margarita; Sreejith, A G; Sarpotdar, Mayuresh; Ambily, S; Prakash, Ajin; Mathew, Joice; Murthy, Jayant; Anand, Devarajan; Kapardhi, B V N; Kumar, B Suneel; Kulkarni, P M

    2016-01-01

    Balloon experiments are an economically feasible method of conducting observations in astronomy that are not possible from the ground. The astronomical payload may include a telescope, a detector, and a pointing/stabilization system. Determining the attitude of the payload is of primary importance in such applications, to accurately point the detector/telescope to the desired direction. This is especially important in generally unstable lightweight balloon flights. However, the conditions at float altitudes, which can be reached by zero pressure balloons, could be more stable, enabling accurate pointings. We have used the Inertial Measurement Unit (IMU), placed on a stratospheric zero pressure balloon, to observe 3-axis motion of a balloon payload over a fight time of 4.5 hours, from launch to the float altitude of 31.2 km. The balloon was launched under nominal atmospheric conditions on May 8th 2016, from a Tata Institute of Fundamental Research Balloon Facility, Hyderabad.

  16. Evaluating shoulder instability treatment

    OpenAIRE

    Linde, J. A.

    2016-01-01

    Shoulder instability common occurs. When treated nonoperatively, the resulting societal costs based on health care utilization and productivity losses are significant. Shoulder function can be evaluated using patient reported outcome measurements (PROMs). For shoulder instability, these include the Western Ontario Shoulder Instability index (WOSI) and the Oxford Shoulder Instability Score (OSIS). When translated and validated for the dutch population, both have good measurment properties. Sco...

  17. Balloon-borne gamma-ray polarimetry

    CERN Document Server

    Pearce, Mark

    2011-01-01

    The physical processes postulated to explain the high-energy emission mechanisms of compact astrophysical sources often yield polarised soft gamma rays (X-rays). PoGOLite is a balloon-borne polarimeter operating in the 25-80 keV energy band. The polarisation of incident photons is reconstructed using Compton scattering and photoelectric absorption in an array of phoswich detector cells comprising plastic and BGO scintillators, surrounded by a BGO side anticoincidence shield. The polarimeter is aligned to observation targets using a custom attitude control system. The maiden balloon flight is scheduled for summer 2011 from the Esrange Space Centre with the Crab and Cygnus X-1 as the primary observational targets.

  18. Pneumothorax, music and balloons: A case series

    OpenAIRE

    2013-01-01

    We describe two cases of spontaneous pneumothorax in young healthy adults with no underlying structural lung disease. The onset of pneumothorax was following physical activity including playing musical instruments and blowing of balloons. There is sparse data evaluating the pathophysiology of primary spontaneous pneumothorax in relation to increased mouth pressures. These cases highlight the possible physical effect of valsalva manoeuvre on transpulmonary pressures, and the potential risk of ...

  19. Coronary artery dissection by an oversized balloon.

    Science.gov (United States)

    Yafi, Wael; Jacquemin, Laurent

    2014-01-01

    Percutaneous coronary intervention (PCI) as a treatment of coronary artery disease can be a simple, rapid procedure with a clear benefit for the patient, but it could also become a complex procedure with fatal consequences. These complications depend on the lesion itself, material used and also on operating staff. In this case we report a coronary artery dissection of the circumflex (CX) artery caused by inflation of an oversized balloon. We discuss here the management and evolution of this complication. PMID:25479753

  20. Double balloon enteroscopy examinations in general anesthesia

    Institute of Scientific and Technical Information of China (English)

    Laszlo; Zubek; Lena; Szabo; Peter; Laszlo; Lakatos; Janos; Papp; Janos; Gal; Gabor; Elo

    2010-01-01

    AIM:To demonstrate that the double balloon enteroscopy(DBE) can be safely performed in general anesthesia with intubation.METHODS:We performed a retrospective examination between August 2005 and November 2008 amongpatients receiving intubation narcosis due to DBE examination.The patients were grouped based on sex,age and physical status.Anesthesia records includedduration of anesthesia,quantity of medication usedand anesthesia-related complications.We determinedthe frequency of complications in the differen...

  1. Lightweight Reusable Solar Array For Balloons

    Science.gov (United States)

    Aaron, K.; Tensor, P.; Nock, K.; Wyszkowski, C.

    We will discuss a new lightweight reusable solar array system, dubbed HighPower, which is being developed for the Ultra-Long Duration Balloon (ULDB) program using NASA/SBIR funding, but which is also applicable to other balloon systems. The system uses a vertically deployed stack of panels suspended from their corners by cables. The stack act likes a two-dimensional Venetian blind. By raising and lowering opposite corners, the array of parallel panels can be pointed over most of the upper hemisphere. This allows the panels to remain normal to the sun despite the slow rotation of the gondola and without requiring rotation of the system (no slip rings) or heavy cantilevered rotation joints. The system is sized to generate 2000 W using six 2m x 2m panels. The modularity of the system allows panels to be added or removed to tailored the power to the needs of the mission. Prior to cut -down of the balloon, the panels can be retracted and stowed compactly in the lower part of the gondola. This will protect the array during landing, allowing the array to be reused on subsequent flights.

  2. Shoulder instability; Schulterinstabilitaeten

    Energy Technology Data Exchange (ETDEWEB)

    Kreitner, Karl-Friedrich [Mainiz Univ. (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie

    2014-06-15

    In the shoulder, the advantages of range of motion are traded for the disadvantages of vulnerability to injury and the development of instability. Shoulder instability and the lesion it produces represent one of the main causes of shoulder discomfort and pain. Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to their causative factors as the pathogenesis of instability plays an important role with respect to treatment options: instabilities are classified in traumatic and atraumatic instabilities as part of a multidirectional instability syndrome, and in microtraumatic instabilities. Plain radiographs ('trauma series') are performed to document shoulder dislocation and its successful reposition. Direct MR arthrography is the most important imaging modality for delineation the different injury patterns on the labral-ligamentous complex and bony structures. Monocontrast CT-arthrography with use of multidetector CT scanners may be an alternative imaging modality, however, regarding the younger patient age, MR imaging should be preferred in the diagnostic work-up of shoulder instabilities. (orig.)

  3. Fluoroscopically Guided Balloon Dilation for Postintubation Tracheal Stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woong Hee; Kim, Jin Hyoung, E-mail: m1fenew@daum.net; Park, Jung-Hun [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of)

    2013-10-15

    Purpose: Little was known about the safety and long-term efficacy of fluoroscopically guided balloon dilation for postintubation tracheal stenosis. The purpose of this study was to evaluate the safety and long-term efficacy of fluoroscopically guided balloon dilation in patients with postintubation tracheal stenosis. Methods: From February 2000 to November 2010, 14 patients underwent fluoroscopically guided balloon dilation for postintubation tracheal stenosis. Technical success, clinical success, and complications were evaluated. Patients were followed up for recurrent symptoms. Results: In all patients, fluoroscopically guided balloon dilation was technically and clinically successful with no major complications. Following the initial procedure, six patients (43 %) remained asymptomatic during a follow-up period. Obstructive symptoms recurred in eight patients (57 %) within 6 months (mean, 1.7 months), who were treated with repeat balloon dilation (n = 4) and other therapies. Of the four patients who underwent repeat balloon dilation, three became asymptomatic. One patient became asymptomatic after a third balloon dilation. On long-term (mean, 74 months) follow-up, 71 % of patients experienced relief of symptoms following fluoroscopically guided balloon dilation. Conclusions: Fluoroscopically guided balloon dilation may be safe, is easy to perform, and resulted in effective treatment in patients with postintubation tracheal stenosis.

  4. Acoustical characterization of exploding hydrogen-oxygen balloons.

    Science.gov (United States)

    Vernon, Julia A; Gee, Kent L; Macedone, Jeffrey H

    2012-03-01

    Exploding hydrogen-oxygen balloons are popular chemistry demonstrations. Although initial research experimentally quantified potential hearing risk via analysis of peak levels [K. L. Gee et al., J. Chem. Educ. 87, 1039-1044 (2010)], further waveform and spectral analyses have been conducted to more fully characterize these impulsive noise sources. While hydrogen-only balloons produce inconsistent reactions and relatively low, variable levels, stoichiometrically mixed hydrogen-oxygen balloons produce consistent high-amplitude noise waveforms. Preliminary consideration is also given to the potential use of these exploding balloons in architectural acoustics applications. PMID:22423815

  5. AUTOPERFUSION BALLOON CATHETER FOR COMPLICATED CORONARY ANGIOPLASTY - A PROSPECTIVE-STUDY WITH RETROSPECTIVE CONTROLS

    NARCIS (Netherlands)

    DEMUINCK, ED; VANDIJK, RB; DENHEIJER, P; MEEDER, JG; LIE, KI

    1992-01-01

    Prolonged angioplasty balloon inflation with an autoperfusion balloon for failed conventional coronary angioplasty, was compared with emergency surgery for this condition. Restenosis was assessed 6 weeks after successful intervention with the autoperfusion balloon. Forty consecutive patients with pe

  6. Stratospheric composition from balloon based measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mencaraglia, F.; Carli, B. [Ist. per le Ricerche sulle Onde Elettromagnetiche, Firenze (Italy); Bonetti, A.; Ciarpallini, P. [Univ. di Firenze (Italy); Carlotti, M.; Lepri, G. [Univ. di Bologna (Italy); Alboni, F.; Cortesi, U.; Ridolfi, M. [Fondazione per la Metereologia Applicata, Firenze (Italy)

    1995-12-31

    Measurements of the composition of the earth`s atmosphere is of fundamental importance for the study of atmospheric chemistry and for developing models that can predict the evolution of the atmosphere itself. Here, the chemical composition of the lower stratosphere has been measured using a polarizing interferometer operating in the far infrared and submillimetric spectral region. The instrument was flown three times (in 1992, 1993 and 1994) from the NSBF balloon base (Fort Sumner, New Mexico) in coincidence with overpasses of the UARS satellite, for a total of about 50 hours of measurements. In this paper the authors report some of the results obtained from the data analysis made up to now.

  7. Guidelines and Suggestions for Balloon Gondola Design

    Science.gov (United States)

    Franco, Hugo

    2016-01-01

    The Columbia Scientific Balloon Facility is responsible for ensuring that science payloads meet the appropriate design requirements. The ultimate goal is to ensure that payloads stay within the allowable launch limits as well as survive the termination event. The purpose of this presentation is to provide some general guidelines for Gondola Design. These include rules and reasons on why CSBF has a certain preference and location for certain components within the gondola as well as other suggestions. Additionally, some recommendations are given on how to avoid common pitfalls.

  8. General theory of kinetic ballooning modes

    International Nuclear Information System (INIS)

    The ballooning mode formalism, previously developed for the ideal MHD problem, is applied here to the kinetic problem in tokamaks. The general two-dimensional equation governing drift and trapped-electron eigenmodes reduces to a one-dimensional integral equation along the lines of force with the radial structure determined by a WKB procedure. Comparisons made between the present one-dimensional code and a previous two-dimensional code embodying identical physical assumptions indicate reasonable agreement. This correspondence holds both for the structure along the field line and for the radial structure in the special case of closely spaced turning points

  9. Pneumothorax, music and balloons: A case series

    Directory of Open Access Journals (Sweden)

    Shiferaw Dejene

    2013-01-01

    Full Text Available We describe two cases of spontaneous pneumothorax in young healthy adults with no underlying structural lung disease. The onset of pneumothorax was following physical activity including playing musical instruments and blowing of balloons. There is sparse data evaluating the pathophysiology of primary spontaneous pneumothorax in relation to increased mouth pressures. These cases highlight the possible physical effect of valsalva manoeuvre on transpulmonary pressures, and the potential risk of developing pneumothorax in otherwise healthy individuals. This aspect of pneumothorax development is worthy of further exploration, to better elucidate the mechanism and enhance our understanding of this common respiratory presentation.

  10. 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? PMID:27543477

  11. Ballooning Spiders: The Case for Electrostatic Flight

    CERN Document Server

    Gorham, Peter W

    2013-01-01

    We consider general aspects of the physics underlying the flight of Gossamer spiders, also known as ballooning spiders. We show that existing observations and the physics of spider silk in the presence of the Earth's static atmospheric electric field indicate a potentially important role for electrostatic forces in the flight of Gossamer spiders. A compelling example is analyzed in detail, motivated by the observed "unaccountable rapidity" in the launching of such spiders from H.M.S. Beagle, recorded by Charles Darwin during his famous voyage.

  12. Double-balloon endoscopy: Who needs it?

    DEFF Research Database (Denmark)

    Hendel, J.W.; Vilmann, P.; Jensen, T.

    2008-01-01

    Objective. Double-balloon endoscopy (DBE) made the small bowel accessible to inspection and therapy in its entirety. However, DBE is a time-consuming procedure that requires a highly skilled endoscopist, several nurses and - more often than not - anesthesiological support. This makes the selection...... of patients for DBE a pivotal point. The mainstay of this screening examination of the small bowel is capsule endoscopy (CE). The aim of this study was to describe the results of this screening procedure and the subsequent DBE in patients with suspected mid-gastrointestinal bleeding (MGIB). Material...

  13. Pneumothorax, music and balloons: A case series.

    Science.gov (United States)

    Dejene, Shiferaw; Ahmed, Fahim; Jack, Kastelik; Anthony, Arnorld

    2013-07-01

    We describe two cases of spontaneous pneumothorax in young healthy adults with no underlying structural lung disease. The onset of pneumothorax was following physical activity including playing musical instruments and blowing of balloons. There is sparse data evaluating the pathophysiology of primary spontaneous pneumothorax in relation to increased mouth pressures. These cases highlight the possible physical effect of valsalva manoeuvre on transpulmonary pressures, and the potential risk of developing pneumothorax in otherwise healthy individuals. This aspect of pneumothorax development is worthy of further exploration, to better elucidate the mechanism and enhance our understanding of this common respiratory presentation. PMID:23922614

  14. 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

  15. Reversible transient apical ballooning syndrome with coronary lesions

    Institute of Scientific and Technical Information of China (English)

    Yunshan Cao; Min Zhang; Xiang Li; Ping Xie; Lynn Cronin

    2009-01-01

    Transient apical ballooning syndrome(Tako-Tsubo syndrome or ampulla cardiomyopathy) occurs predominantly in women over 60 years of age with a history of recent physical or psychological stress. We present a case of a male patient with reversible transient apical ballooning syndrome with significant coronary lesions and other ECG changes that did not explain the clinical symptoms.

  16. 21 CFR 870.1350 - Catheter balloon repair kit.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter balloon repair kit. 870.1350 Section 870... repair kit. (a) Identification. A catheter balloon repair kit is a device used to repair or replace the... effect the repair or replacement. (b) Classification. Class III (premarket approval). (c) Date PMA...

  17. Recent developments in the scientific ballooning in India

    Science.gov (United States)

    Manchanda, R.; Sreenivasan, S.; Subbarao, J.; Kumar, P.

    RECENT DEVELOPMENTS IN THE SCIENTIFIC BALLOONING IN INDIA R. K. Manchanda1, S. Sreenivasan2, J. V. Subbarao2, P. R. Kumar2 1. Tata Institute of Fundamental Research Colaba, Mumbai-400 005, India. 2. TIFR Balloon Facility, PO Box 5, ECIL Post Office, Hyderabad-500 762, India ravi@tifr.res.in/FAX: +91-22-2152110 National Balloon facility operated by TIFR in Hyderabad, India is the only one of its kind in the world, which combines both, the in-house balloon production and a complete flight support for scientific ballooning. In the past few years we 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 m3 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 and the results of the test flight conducted to qualify new sub systems will be presented.

  18. Instability in evolutionary games.

    Directory of Open Access Journals (Sweden)

    Zimo Yang

    Full Text Available BACKGROUND: Phenomena of instability are widely observed in many dissimilar systems, with punctuated equilibrium in biological evolution and economic crises being noticeable examples. Recent studies suggested that such instabilities, quantified by the abrupt changes of the composition of individuals, could result within the framework of a collection of individuals interacting through the prisoner's dilemma and incorporating three mechanisms: (i imitation and mutation, (ii preferred selection on successful individuals, and (iii networking effects. METHODOLOGY/PRINCIPAL FINDINGS: We study the importance of each mechanism using simplified models. The models are studied numerically and analytically via rate equations and mean-field approximation. It is shown that imitation and mutation alone can lead to the instability on the number of cooperators, and preferred selection modifies the instability in an asymmetric way. The co-evolution of network topology and game dynamics is not necessary to the occurrence of instability and the network topology is found to have almost no impact on instability if new links are added in a global manner. The results are valid in both the contexts of the snowdrift game and prisoner's dilemma. CONCLUSIONS/SIGNIFICANCE: The imitation and mutation mechanism, which gives a heterogeneous rate of change in the system's composition, is the dominating reason of the instability on the number of cooperators. The effects of payoffs and network topology are relatively insignificant. Our work refines the understanding on the driving forces of system instability.

  19. Lateral elbow instability

    Directory of Open Access Journals (Sweden)

    Harry Dominic Stracey Clitherow

    2014-01-01

    Full Text Available Lateral elbow stability utilises a combination of bony and soft tissue constraints. Lateral elbow instability is usually associated with an episode of elbow dislocation. Isolated lateral ligament complex insufficiency results in posterolateral rotatory instability (PLRI, The most common presentation is lateral elbow discomfort and a sensation of instability, without recurrent dislocation. The lateral pivot shift test is unreliable for diagnosing PLRI when the patient is awake due to significant apprehension. Stress radiographs, fluoroscopy, computed tomography and arthroscopy are all useful investigations to confirm the diagnosis of lateral instability. Surgical treatment is indicated for functional instability. All associated fractures need to be addressed. In severe cases, the medial structures and the posterolateral capsule may also require reconstruction.

  20. EUSO-Balloon: The first flight

    Science.gov (United States)

    Scotti, Valentina; Osteria, Giuseppe

    2016-07-01

    EUSO-Balloon is a pathfinder mission for JEM-EUSO, the near-UV telescope proposed to be installed on board the International Space Station (ISS). The main objective of this pathfinder mission is to perform a full scale end-to-end test of all the key technologies of JEM-EUSO detectors and to measure the UV background. The JEM-EUSO instrument consists of UV telescope designed to focus the signal of the UV tracks generated by Extreme Energy Cosmic Rays propagating in Earth's atmosphere, onto a finely pixelized UV camera. The EUSO-Balloon instrument, smaller than the one designed for the ISS, was launched on August 2014 from Timmins (Ontario, Canada). The flight lasted about five hours and the instrument reached a float altitude of about 40 km. From this altitude the telescope registered, at a rate of 400 000 frames/s, the nightglow background on forests, lakes and clouds, as well as city lights and artificial air showers tracks generated by means of a laser installed on an helicopter flying inside its field of view. In this contribution we will describe the instrument and its performance during the first flight.

  1. Intravascular ultrasound imaging following balloon angioplasty.

    Science.gov (United States)

    Tobis, J M; Mahon, D J; Moriuchi, M; Honye, J; McRae, M

    1991-01-01

    Despite its long history and reliability, contrast angiography has several inherent limitations. Because it is a two-dimensional projection image of the lumen contour, the wall thickness cannot be measured and the plaque itself is not visualized. This results in an underestimation of the amount of atherosclerotic disease by angiography. An assessment of atherosclerosis could be improved by an imaging modality: (1) that has an inherent larger magnification than angiography and (2) that directly visualizes the plaque. Intravascular ultrasound fulfils these criteria. This presentation will provide evidence that intravascular ultrasound may prove complimentary or even superior to angiography as an imaging modality. Intravascular ultrasound demonstrates excellent representations of lumen and plaque morphology of in vitro specimens compared with histology. There is very close intraobserver and interobserver variability of measurements made from intravascular ultrasound images. Phantom studies of stenoses in a tube model demonstrate that angiography can misrepresent the severity of stenosis when the lumen contour is irregular and not a typical ellipse, whereas intravascular ultrasound reproduces the cross-sectional morphology more accurately since it images the artery from within. In vitro studies of the atherosclerotic plaque tissue characteristics compare closely with the echo representation of fibrosis, calcification, and lipid material. In addition, in vitro studies of balloon angioplasty demonstrate that intravascular ultrasound accurately represents the changes in the structure of artery segments following balloon dilatation. PMID:1833473

  2. Balloon concepts for scientific investigation of Mars and Jupiter

    Science.gov (United States)

    Ash, R. L.

    1979-01-01

    Opportunities for scientific investigation of the atmospheric planets using buoyant balloons have been explored. Mars and Jupiter were considered in this study because design requirements at those planets bracket nominally the requirements at Venus, and plans are already underway for a joint Russian-French balloon system at Venus. Viking data has provided quantitative information for definition of specific balloon systems at Mars. Free flying balloons appear capable of providing valuable scientific support for more sophisticated Martian surface probes, but tethered and powered aerostats are not attractive. The Jovian environment is so extreme, hot atmosphere balloons may be the only scientific platforms capable of extended operations there. However, the estimated system mass and thermal energy required are very large.

  3. An overview of instrumentation capabilities for Scientific ballooning in India

    Science.gov (United States)

    Devarajan, Anand; Reddy Vizapur, Anmi; Rao Tanneeru, Venkateswara; Bangaru, Kapardhi; Trivedi, Dharmesh; Rodi, Ashish; Ojha, Devendra; Koli, Santosh

    2016-07-01

    The Balloon Facility of Tata Institute of Fundamental Research (TIFR-BF) in India, launches scientific balloons for research in the field of astronomy, astrobiology and atmospheric sciences. TIFR-BF not only has the capability to design, fabricate and launch zero-pressure balloons, but also provide operational and engineering support for launching them. The Control Instrumentation Group (CIG) at the balloon facility handles all electronics related to telemetry, telecommand, tracking, real-time data display, data storage, air-safety and payload recovery. In the recent past, it has designed and developed customized electronics and payload orientation mechanism to meet specific experimental objectives. Small, inexpensive and rugged industrial grade radio data modems were successfully deployed in balloon flights for low bit rate data and image telemetry. This paper will provide an overview and in-flight performance of some of the recent developments in instrumentation and electronics systems. Our plans for future upgradations will also be discussed.

  4. 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.”

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

    International Nuclear Information System (INIS)

    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)

  6. A New Paradigm in Space Based Experiments Using Rubber Balloons

    CERN Document Server

    Chakrabarti, Sandip K; Palit, Sourav; Chakraborty, Subhankar; Mondal, Sushanta; Bhattacharyya, Arnab; Middya, Susanta; Chakrabarti, Sonali

    2013-01-01

    Indian Centre for Space Physics is engaged in long duration balloon borne experiments with typical payloads less than ~ 3kg. Low cost rubber balloons are used. In a double balloon system, the booster balloon lifts the orbiter balloon to its cruising altitude where data is taken for a long time. Here we present results of muon detections and recent solar activities, including the light curves and flare spectra in the 20-100keV range. We not only show that we have successfully obtained several flares and there spectra at different altitudes, we also found that the high energy X-ray flux of strong flares at altitudes of 10-13 km (the flight altitude of commercial planes) could be more than the contribution due to cosmic rays.

  7. THE KISSING BALLOON TECHNIQUE WITH 2 OVER-THE-WIRE BALLOON CATHETERS THROUGH A SINGLE 8-FRENCH GUIDING CATHETER

    NARCIS (Netherlands)

    DENHEIJER, P; BERNINK, PJLM; VANDIJK, RB; TWISK, SPM; LIE, KI

    1991-01-01

    Some of the newer over-the-wire coronary angioplasty catheters have shaft sizes of 3.0 French (F) or less. The inner diameter of modern 8-F guiding catheters is large enough to accommodate two of such balloon catheters. We report a kissing balloon procedure with two over-the-wire catheters through a

  8. Study of aspect ratio effects on kinetic MHD instabilities in NSTX and DIII-D

    International Nuclear Information System (INIS)

    We report general observations of kinetic instabilities on the low aspect-ratio National Spherical Torus Experiment (NSTX) and describe explicit aspect ratio scaling studies of kinetic instabilities using both the NSTX and the DIII-D tokamak. The NSTX and the DIII-D tokamak are nearly ideal for such experiments, having a factor of two difference in major radius but otherwise similar parameters. We also introduce new theoretical work on the physics of kinetic ballooning modes (KBM), toroidal Alfven eigenmodes (TAE), and compressional Alfven eigenmodes (CAE) with applications to NSTX. (author)

  9. Nonlinear helical MHD instability

    Energy Technology Data Exchange (ETDEWEB)

    Zueva, N.M.; Solov' ev, L.S.

    1977-07-01

    An examination is made of the boundary problem on the development of MHD instability in a toroidal plasma. Two types of local helical instability are noted - Alfven and thermal, and the corresponding criteria of instability are cited. An evaluation is made of the maximum attainable kinetic energy, limited by the degree to which the law of conservation is fulfilled. An examination is made of a precise solution to a kinematic problem on the helical evolution of a cylindrical magnetic configuration at a given velocity distribution in a plasma. A numerical computation of the development of MHD instability in a plasma cylinder by a computerized solution of MHD equations is made where the process's helical symmetry is conserved. The development of instability is of a resonance nature. The instability involves the entire cross section of the plasma and leads to an inside-out reversal of the magnetic surfaces when there is a maximum unstable equilibrium configuration in the nonlinear stage. The examined instability in the tore is apparently stabilized by a magnetic hole when certain limitations are placed on the distribution of flows in the plasma. 29 references, 8 figures.

  10. Microgravity combustion experiment using high altitude balloon.

    Science.gov (United States)

    Kan, Yuji

    In JAXA, microgravity experiment system using a high altitude balloon was developed , for good microgravity environment and short turn-around time. In this publication, I give an account of themicrogravity experiment system and a combustion experiment to utilize the system. The balloon operated vehicle (BOV) as a microgravity experiment system was developed from 2004 to 2009. Features of the BOV are (1) BOV has double capsule structure. Outside-capsule and inside-capsule are kept the non-contact state by 3-axis drag-free control. (2) The payload is spherical shape and itsdiameter is about 300 mm. (3) Keep 10-4 G level microgravity environment for about 30 seconds However, BOV’s payload was small, and could not mount large experiment module. In this study, inherits the results of past, we established a new experimental system called “iBOV” in order toaccommodate larger payload. Features of the iBOV are (1) Drag-free control use for only vertical direction. (2) The payload is a cylindrical shape and its size is about 300 mm in diameter and 700 mm in height. (3) Keep 10-3-10-4 G level microgravity environment for about 30 seconds We have "Observation experiment of flame propagation behavior of the droplets column" as experiment using iBOV. This experiment is a theme that was selected first for technical demonstration of iBOV. We are conducting the flame propagation mechanism elucidation study of fuel droplets array was placed at regular intervals. We conducted a microgravity experiments using TEXUS rocket ESA and drop tower. For this microgravity combustion experiment using high altitude balloon, we use the Engineering Model (EM) for TEXUS rocket experiment. The EM (This payload) consists of combustion vessel, droplets supporter, droplets generator, fuel syringe, igniter, digital camera, high-speed camera. And, This payload was improved from the EM as follows. (1) Add a control unit. (2) Add inside batteries for control unit and heater of combustion

  11. 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

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

    International Nuclear Information System (INIS)

    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)

  13. National Report France: The French Balloon Programme 2013-2016

    Science.gov (United States)

    Dubourg, V.; Vassaux, D.; Vargas, A.; Cocquerez, P.; Louvel, S.; Douchin, F.; Saccocio, M.; Mirc, F.

    2015-09-01

    With over 50 years' experience in the field, the French Centre National dEtudes Spatiales (CNES) goes on supporting a significant scientific ballooning program. In particular so because balloons still give a unique access to near space science. Over the past 6 years, most of the systems, beginning by the Zero Pressure Balloons, had to be renewed to comply with more stringent Safety constraints and to growing performance and reliability requirements from the scientific missions. This paper will give an overview of the CNES new capabilities and services for operational balloon activities, and their availability status. The scientific launch campaigns of the past two years will be presented. A focus will be made on the results of the Stratoscience 2014 flight campaign from Timmins, Ontario, using the NOSYCA command and control system for zero pressure balloons, qualified in 2013. The ChArMEx campaign (Chemistry-AeRosol Mediterranean Experiment) performed in 2013 from the Baleares islands and from the south of France, with Boundary Layer Pressurized Balloons will also be presented as well as the LOAC-VOLTAIRE experiment, carried out from Aire-sur-l'Adour (France), through the flights of 20 instrumented light expandable balloons. An outlook of the new stratospheric long duration flight systems currently studied at CNES will be given. The scientific launch campaigns and the main payloads in the study for the near future will also be presented.

  14. Graph-Based Path-Planning for Titan Balloons

    Science.gov (United States)

    Blackmore, Lars James; Fathpour, Nanaz; Elfes, Alberto

    2010-01-01

    A document describes a graph-based path-planning algorithm for balloons with vertical control authority and little or no horizontal control authority. The balloons are designed to explore celestial bodies with atmospheres, such as Titan, a moon of Saturn. The algorithm discussed enables the balloon to achieve horizontal motion using the local horizontal winds. The approach is novel because it enables the balloons to use arbitrary wind field models. This is in contrast to prior approaches that used highly simplified wind field models, such as linear, or binary, winds. This new approach works by discretizing the space in which the balloon operates, and representing the possible states of the balloon as a graph whose arcs represent the time taken to move from one node to another. The approach works with arbitrary wind fields, by looking up the wind strength and direction at every node in the graph from an arbitrary wind model. Having generated the graph, search techniques such as Dijkstra s algorithm are then used to find the set of vertical actuation commands that takes the balloon from the start to the goal in minimum time. In addition, the set of reachable locations on the moon or planet can be determined.

  15. Ballooning of CANDU pressure tubes. Model assessment

    International Nuclear Information System (INIS)

    The transient creep equations used to analyze the possible ballooning and failure of Zr-2.5% Nb pressure tubes during a loss-of-coolant accident (LOCA) were developed and verified using as-received Zr-2.5% Nb pressure tube material. But in a CANDU reactor, the pressure tubes absorb deuterium and are exposed to a continuous neutron fluence. Consequently, a literature survey was done to determine how irradiation damage and deuterium might affect the creep rate and ductility of Zr-2.5% Nb pressure tubes in the temperature range from 600 to 800 degrees C. It was found that irradiation damage, dissolved deuterium and deuteride blisters could possibly affect the creep rate and ductility of ZR-2.5% Nb pressure tubes in this temperature range, but deuteride platelets are expected to have little effect. Further tests are required to determine the effect of irradiation damage and deuterium on the creep rate and ductility of pressure tubes

  16. The Norwegian Sounding Rocket and Balloon Program

    Science.gov (United States)

    Skatteboe, Rolf

    2001-08-01

    The status and recent developments of the Norwegian Sounding Rocket and Balloon Program are presented with focus on national activities and recent achievements. The main part of the Norwegian program is sounding rocket launches conducted by Andøya Rocket Range from the launch facilities on Andøya and at Svalbard. For the majority of the programs, the scientific goal is investigation of processes in the middle and upper atmosphere. The in situ measurements are supplemented by a large number of ground-based support instruments located at the ALOMAR Observatory. The ongoing and planned projects are described and the highlights of the latest completed projects are given. The scientific program for the period 2001-2003 will be reviewed. Several new programs have been started to improve the services available to the international science comunity. The Hotel Payload project and MiniDusty are important examples that will be introduced in the paper. Available space related infrastructure is summarized.

  17. Intragastric balloon: ethics, medical need and cosmetics.

    Science.gov (United States)

    Kotzampassi, Katerina; Shrewsbury, Anne D

    2008-01-01

    The development of the intragastic balloon as a safe, noninvasive, alternative method to weight reduction raises all the ethical questions routinely faced by practitioners of other forms of cosmetic surgery. In the case of the morbidly, severely or merely obese, the surgeon is faced with a medical decision in a situation defined by medical parameters. The case of the overweight or normal may, however, create an ethical dilemma in which the doctor is forced to make decisions of a nonmedical nature, for which his training has not prepared him, and relating essentially to his personal attitudes and moral beliefs, culture and the recognition that 'if I don't, somebody else--possibly less competent--will'.

  18. The Collisionless Magnetothermal Instability

    CERN Document Server

    Islam, Tanim

    2013-01-01

    It is likely that nearly all central galactic massive and supermassive black holes are nonradiative: their accretion luminosities are orders of magnitude below what can be explained by efficient black hole accretion within their ambient environments. These objects, of which Sagittarius A* is the best-known example, are also dilute (mildly collisional to highly collisionless) and optically thin. In order for accretion to occur, magnetohydrodynamic instabilities must develop that not only transport angular momentum, but also gravitational energy generated through matter infall, outwards. A class of new magnetohydrodynamical fluid instabilities -- the magnetoviscous-thermal instability (MVTI) (Islam12) -- was found to transport angular momentum and energy along magnetic field lines through large (fluid) viscosities and thermal conductivities. This paper describes the collisionless and mildly collisional analogue to the MVTI, the collisional magnetothermal instability (CMTI), that similarly transports energy and ...

  19. Chronic Ankle Instability

    Science.gov (United States)

    ... ankle surgeon will ask you about any previous ankle injuries and instability. Then s/he will examine your ankle ... Weak ankles may be a result of previous ankle injuries, but in some cases they are a congenital ( ...

  20. Imaging in carpal instability.

    Science.gov (United States)

    Ramamurthy, N K; Chojnowski, A J; Toms, A P

    2016-01-01

    Carpal instability is a complex and heterogeneous clinical condition. Management requires accurate identification of structural injury with an understanding of the resultant movement (kinematic) and load transfer (kinetic) failure. Static imaging techniques, such as plain film radiography, stress views, ultrasound, magnetic resonance, MR arthrography and computerized tomography arthrography, may accurately depict major wrist ligamentous injury. Dynamic ultrasound and videofluoroscopy may demonstrate dynamic instability and kinematic dysfunction. There is a growing evidence base for the diagnostic accuracy of these techniques in detecting intrinsic ligament tears, but there are limitations. Evidence of their efficacy and relevance in detection of non-dissociative carpal instability and extrinsic ligament tears is weak. Further research into the accuracy of existing imaging modalities is still required. Novel techniques, including four-dimensional computerized tomography and magnetic resonance, can evaluate both cross-sectional and functional carpal anatomy. This is a narrative review of level-III studies evaluating the role of imaging in carpal instability. PMID:26586689

  1. Rotor internal friction instability

    Science.gov (United States)

    Bently, D. E.; Muszynska, A.

    1985-01-01

    Two aspects of internal friction affecting stability of rotating machines are discussed. The first role of internal friction consists of decreasing the level of effective damping during rotor subsynchronous and backward precessional vibrations caused by some other instability mechanisms. The second role of internal frication consists of creating rotor instability, i.e., causing self-excited subsynchronous vibrations. Experimental test results document both of these aspects.

  2. Validation of IASI ozone profiles, using balloon sounding data

    OpenAIRE

    Delcloo, Andy; Hurtmans, Daniel; Coheur, Pierre-François; Clerbaux, Cathy

    2011-01-01

    Here we present a validation study of IASI vertical ozone profiles. This has been done using balloon ozone sonde data, which have a vertical resolution of about 100 m and measures ozone from the surface up to an altitude of about 30 km. IASI vertical ozone profiles are given as partial ozone columns [in DU per layer] between varying pressure levels. To validate the satellite derived ozone layers with the balloon ozone sounding data we integrate the ozone measured by the balloon ozone sounding...

  3. Balloon-dilatation of esophageal strictures in children

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, A.; Ingemann Jensen, L.; Mauritzen, K.

    1986-07-01

    Dilatation of benign esophageal strictures by means of a balloon-catheter is a well-established procedure in adults. This method is also useful in children. The technique is described and the results of treatment in 10 children are reported. In all our patients the stricture developed after an operation for esophageal atresia with an end-to-end anastomosis. Dilatation with a balloon-catheter seems to have the same or an even better effect than the traditional dilatation with bougies. Complications following balloon-dilatations have been few and negligible in this series and dilatations can be performed using sedation instead of general anaesthesia. Therefore, this method is recommended.

  4. Intragastric balloon for morbid obesity causing chronic gastric dilatation

    International Nuclear Information System (INIS)

    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.)

  5. Results of the first EUSO-Balloon flight

    Science.gov (United States)

    Miyamoto, H.; Bertaina, M.; JEM-EUSO Collaboration

    2016-05-01

    EUSO-Balloon, a balloon-borne diffractive fluorescence telescope, was launched by the French Space Agency ONES from the Timmins base in Ontario (Canada) on August 25th in 2014. After reaching the floating altitude of about 38 km, EUSO-Balloon imaged the UV background for more than 5 hours before descending to ground using the key technologies of JEM-EUSO. A detailed and precise measurement of the UV background in different atmospheric and ground conditions was achieved. The instrument proved the capability of detecting Extensive Air Showers (EAS) by observing laser tracks with similar characteristics. This contribution will summarise the first results obtained concerning all the topics described above.

  6. 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)

  7. 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.)

  8. Ion temperature gradient instability at sub-Larmor radius scales with non-zero ballooning angle

    CERN Document Server

    Migliano, Pierluigi; Casson, Francis; Hornsby, William; Peeters, Arthur

    2012-01-01

    Linear gyro-kinetic stability calculations predict unstable toroidal Ion Temperature Gradient modes with normalised poloidal wave vectors well above one ($k_\\theta \\rho_i > 1$) for standard parameters and with adiabatic electrons. These modes have a maximum amplitude at a poloidal angle $\\theta$ that is shifted away from the low field side ($\\theta \

  9. CLIMB: cosmic light isotopes and muons with balloons

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, M. E-mail: pearce@particle.kth.se; Adriani, O.; Boezio, M.; Bonvicini, V.; Carlson, P.; Mocchiutti, E.; Papini, P.; Straulino, S.; Vacchi, A.; Vannuccini, E.; Zampa, G.; Zampa, N

    2004-06-01

    A new balloon-borne experiment is proposed which will measure high-energy light isotopes at the top of the Earth's atmosphere and cosmic ray muons at fixed altitudes within the Earth's atmosphere.

  10. 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.

  11. Current status of intragastric balloon for obesity treatment

    Science.gov (United States)

    Kim, Seung Han; Chun, Hoon Jai; Choi, Hyuk Soon; Kim, Eun Sun; Keum, Bora; Jeen, Yoon Tae

    2016-01-01

    Endoscopic bariatric therapy may be a useful alternative to pharmacological treatment for obesity, and it provides greater efficacy with lower risks than do conventional surgical procedures. Among the various endoscopic treatments for obesity, the intragastric balloon is associated with significant efficacy in body weight reduction and relief of comorbid disease symptoms. Anatomically, this treatment is based on gastric space-occupying effects that increase the feeling of satiety and may also affect gut neuroendocrine signaling. The simplicity of the intragastric balloon procedure may account for its widespread role in obesity treatment and its applicability to various degrees of obesity. However, advances in device properties and procedural techniques are still needed in order to improve its safety and cost-effectiveness. Furthermore, verification of the physiological outcomes of intragastric balloon treatment and the clinical predictive factors for treatment responses should be considered. In this article, we discuss the types, efficacy, safety, and future directions of intragastric balloon treatment. PMID:27350727

  12. 10 meter Sub-Orbital Large Balloon Reflector (LBR) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Besides serving as a launch vehicle, the carrier balloon provides a stable mount for the enclosed telescope. Looking up, the LBR will serve as a telescope. Looking...

  13. Proposed techniques for launching instrumented balloons into tornadoes

    Science.gov (United States)

    Grant, F. C.

    1971-01-01

    A method is proposed to introduce instrumented balloons into tornadoes by means of the radial pressure gradient, which supplies a buoyancy force driving to the center. Presented are analytical expressions, verified by computer calculations, which show the possibility of introducing instrumented balloons into tornadoes at or below the cloud base. The times required to reach the center are small enough that a large fraction of tornadoes are suitable for the technique. An experimental procedure is outlined in which a research airplane puts an instrumented, self-inflating balloon on the track ahead of the tornado. The uninflated balloon waits until the tornado closes to, typically, 750 meters; then it quickly inflates and spirals up and into the core, taking roughly 3 minutes. Since the drive to the center is automatically produced by the radial pressure gradient, a proper launch radius is the only guidance requirement.

  14. Low Cost Variable Conductance Heat Pipe for Balloon Payload Project

    Data.gov (United States)

    National Aeronautics and Space Administration — While continuously increasing in complexity, the payloads of terrestrial high altitude balloons need a thermal management system to reject their waste heat and to...

  15. Isothermal pumping analysis for high-altitude tethered balloons

    OpenAIRE

    Kuo, Kirsty A.; Hunt, Hugh E.M.

    2015-01-01

    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...

  16. Small Research Balloons in a Physics Course for Education Majors

    Science.gov (United States)

    Bruhweiler, F. C.; Verner, E.; Long, T.; Montanaro, E.

    2013-12-01

    At The Catholic Univ. of America, we teach an experimental physics course entitled Physics 240: The Sun-Earth Connection, which is designed for the undergraduate education major. The emphasis is on providing hands-on experience and giving the students an exciting experience in physics. As part of this course, in the Spring 2013 semester, we instituted a project to plan, build, launch, and retrieve a small (~1.3 kg) research balloon payload. The payload flown was a small GPS unit that sent its position to an Internet site, a small wide-angle high-resolution video camera, and an analog refrigerator thermometer placed in the field of view of the camera. All data were stored on the camera sim-card. Students faced the problems of flying a small research balloon in the congested, densely populated Northeast Corridor of the US. They used computer simulators available on the Web to predict the balloon path and flight duration given velocities for the Jet Stream and ground winds, as well as payload mass and amount of helium in the balloon. The first flight was extremely successful. The balloon was launched 140 km NW of Washington DC near Hagerstown, MD and touched down 10 miles (16 km) NW of York, PA, within 1.6 km of what was predicted. The balloon reached 73,000 ft (22,000 m) and the thermometer indicated temperatures as low as -70 degrees Fahrenheit (-57 C) during the flight. Further balloon flights are planned in conjunction with this course. Additional exercises and experiments will be developed centered around these flights. Besides learning that science can be exciting, students also learn that science is not always easily predictable, and that these balloon flights give an understanding of many of problems that go into real scientific space missions. This project is supported in part by an educational supplement to NASA grant NNX10AC56G

  17. The Hubble party balloon and the expanding universe

    Science.gov (United States)

    Zendri, G.; Rosi, T.; Oss, S.

    2016-09-01

    We show that the metaphor of the inflated balloon used to describe expanding space-time according to the Hubble law can be transformed into a simple laboratory experiment. We obtain, in terms of measured recession speeds and distances of ink dots drawn on a party balloon, easy renditions of various cosmological models, such as the static one and the Einstein-De Sitter universe.

  18. Instability of the Heliopause

    International Nuclear Information System (INIS)

    The heliopause (HP) separates the tenuous hot heliosheath plasma from the relatively dense cool magnetized plasma of the local interstellar medium (LISM). Fluid acceleration in the HP region can therefore drive Rayleigh-Taylor-like and Kelvin-Helmholtz- like instabilities. Charge exchange coupling of plasma ions and primary interstellar neutral atoms provides an effective gravity, suggesting the possibility of Rayleigh Taylor-like (RT-like) instabilities. Shear flow due to the velocity difference between the heliosheath and the interstellar flows drives Kelvin Helmholtz-like (KH-like) modes on the heliopause. Magnetic fields damp the classical KH instability. However, we show that energetic neutral atoms (ENAs) destabilize KH-modes,even in the presence of interplanetary and interstellar magnetic fields. We consider a model that includes a number of effects that are important in the heliosphere such as resonant change exchange between the primary neutrals and the solar wind plasma, ENAs from the inner heliosheath, plasma flows along the heliopause and magnetic fields in the inner and outer heliosheath. We find that the nose region is unstable to RT-like modes for HP parameters, while the shoulder region is unstable to a new instability that has the characteristics of a mixed RT-KH-like mode. These instabilities are not stabilized by typical values of the magnetic fields in the inner and outer heliosheath close to the nose and shoulder regions. Whereas ENAs have a stabilizing influence on the RT instability in the vicinity of the nose region (due to counter streaming), they have a destabilizing influence on the KH instability in the vicinity of the flanks. We find that even in the presence of interplanetary and interstellar magnetic fields, ENAs can drive a new form of KH-like instability on the flanks. An analysis of the collisional and anomalous magnetic field diffusion time scales shows that ideal MHD is an appropriate model at the HP. The interstellar magnetic

  19. Plasma physics and instabilities

    International Nuclear Information System (INIS)

    These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)

  20. Development of a tiny tandem balloon system for atmospheric observation

    Science.gov (United States)

    Saito, Yoshitaka; Yamada, Kazuhiko; Fujiwara, Masatomo

    2016-07-01

    A tandem balloon system with a combination of a zero-pressure balloon on top and a super-pressure balloon on the bottom has a unique trajectory characteristic, with different flight altitudes between day and night and thus with ascending and descending motions at dawn and dusk, respectively. This characteristic provides a unique opportunity to explore the atmosphere, e.g., the upper tropospheric and lower stratospheric region with cross-tropopause measurements twice a day. We started development of a tiny tandem balloon system using a 10 m^{3} super-pressure balloon and a 100 m^{3} zero-pressure balloon, with a capability of carrying 3 kg of payload. One of the scientific targets is to measure water vapor, cloud particles, and temperature around the tropical tropopause which is the entry point of the stratospheric and mesospheric meridional circulation. For the data transfer, the iridium satellite communication module, SBD9603 is used. In this paper, the current status of the development will be reported.

  1. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    Vishnu M Bannur

    2001-10-01

    We derive relativistic fluid set of equations for neutrinos and electrons from relativistic Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dispersion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming instability. It contains new, nonelectromagnetic, neutrino-plasma (or electroweak) stable and unstable modes also. The growth of the instability is weak for the highly relativistic neutrino flux, but becomes stronger for weakly relativistic neutrino flux in the case of parameters appropriate to the early universe and supernova explosions. However, this mode is dominant only for the beam velocity greater than 0.25 and in the other limit electroweak unstable mode takes over.

  2. Instabilities in astrophysical jets

    International Nuclear Information System (INIS)

    Instabilities in astrophysical jets are studied in the nonlinear regime by performing 2D numerical classical gasdynamical calculations. The instabilities which arise from unsteadiness in output from the central engine feeding the jets, and those which arise from a beam in a turbulent surrounding are studied. An extra power output an order of magnitude higher than is normally delivered by the engine over a time equal to (nozzle length)/(sound velocity at centre) causes a nonlinear Kelvin-Helmholtz instability in the jet walls. Constrictions move outwards, but the jet structure is left untouched. A beam in turbulent surroundings produces internal shocks over distances of a few beam widths. If viscosity is present the throughput of material is hampered on time scales of a few beam radius sound travel times. The implications are discussed. (Auth.)

  3. The Walking Droplet Instability

    Science.gov (United States)

    Bostwick, Joshua; Steen, Paul

    2013-11-01

    A droplet of liquid that partially wets a solid substrate assumes a spherical-cap equilibrium shape. We show that the spherical-cap with a mobile contact-line is unstable to a non-axisymmetric disturbance and we characterize the instability mechanism, as it depends upon the wetting properties of the substrate. We then solve the hydrodynamic problem for inviscid motions showing that the flow associated with the instability correlates with horizontal motion of the droplet's center-of-mass. We calculate the resulting ``walking speed.'' A novel feature is that the energy conversion mechanism is not unique, so long as the contact-line is mobilized. Hence, the walking droplet instability is potentially significant to a number of industrial applications, such as self-cleansing surfaces or energy harvesting devices.

  4. Causes of genome instability

    DEFF Research Database (Denmark)

    Langie, Sabine A S; Koppen, Gudrun; Desaulniers, Daniel;

    2015-01-01

    Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus......, genome instability can be defined as an enhanced tendency for the genome to acquire mutations; ranging from changes to the nucleotide sequence to chromosomal gain, rearrangements or loss. This review raises the hypothesis that in addition to known human carcinogens, exposure to low dose of other...... chemicals present in our modern society could contribute to carcinogenesis by indirectly affecting genome stability. The selected chemicals with their mechanisms of action proposed to indirectly contribute to genome instability are: heavy metals (DNA repair, epigenetic modification, DNA damage signaling...

  5. 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

  6. 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(4.000: 291-296

  7. Alpha particle effects on MHD ballooning

    International Nuclear Information System (INIS)

    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

  8. Ringed accretion disks: instabilities

    CERN Document Server

    Pugliese, D

    2016-01-01

    We analyze the possibility that several instability points may be formed, due to the Paczy\\'nski mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider recently proposed model of ringed accretion disk, made up by several tori (rings) which can be corotating or counterrotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

  9. Mixing through shear instabilities

    CERN Document Server

    Brüggen, M

    2000-01-01

    In this paper we present the results of numerical simulations of the Kelvin-Helmholtz instability in a stratified shear layer. This shear instability is believed to be responsible for extra mixing in differentially rotating stellar interiors and is the prime candidate to explain the abundance anomalies observed in many rotating stars. All mixing prescriptions currently in use are based on phenomenological and heuristic estimates whose validity is often unclear. Using three-dimensional numerical simulations, we study the mixing efficiency as a function of the Richardson number and compare our results with some semi-analytical formalisms of mixing.

  10. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Bourezak, Rafik; Boulet, Benoit; Lamouche, Guy

    2010-08-01

    We present an innovative integration of an intravascular optical coherence tomography probe into a computerized balloon deployment system to monitor the balloon inflation process. The high-resolution intraluminal imaging of the balloon provides a detailed assessment of the balloon quality and, consequently, a technique to improve the balloon manufacturing process. A custom-built swept-source optical coherence tomography system is used for real-time imaging. A semicompliant balloon with a nominal diameter of 4 mm is fabricated for the experiments. Imaging results correspond to balloon deployment in air and inside an artery phantom. A characterization of the balloon diameter, wall thickness, compliance, and elastic modulus is provided, based on image segmentation. Using the images obtained from the probe pullback, a three-dimensional visualization of the inflated balloon is presented.

  11. Development of a super-pressure balloon with a diamond-shaped net --- result of a ground inflation test of a 2,000 cubic-meter balloon ---

    Science.gov (United States)

    Saito, Yoshitaka; Nakashino, Kyoichi; Akita, Daisuke; Matsushima, Kiyoho; Shimadu, Shigeyuki; Goto, Ken; Hashimoto, Hiroyuki; Matsuo, Takuma

    2016-07-01

    A light super-pressure balloon has been developed using a method to cover a balloon with a diamond-shaped net of high-tensile fibers. The goal is to fly a payload of 900 kg to the altitude of 37 km with a 300,000 m^{3} balloon. Beginning from a demonstration test of the net-balloon with a 10 m^{3} balloon in 2010, we have been polished the net-balloon through ground inflation tests and flight tests, including a flight test of a 3,000 m ^{3} balloon in the tandem balloon configuration with a 15,000 m^{3} zero-pressure balloon in 2012, and a flight test of a 10 m^{3} balloon in the tandem balloon configuration with a 2 kg rubber balloon in 2013, as reported in the last COSPAR. In 2014, we developed a 5,000 m^{3} balloon and performed a ground inflation test to find that the balloon burst from a lip panel for termination with a differential pressure of 425 Pa. It was due to a stress concentration at the edge of a thick tape attached along the termination mechanism. In 2015, we modified the balloon by adding tapes on the lip panel to avoid the stress concentration, and also shorten the net length to leave some margin of the film and performed a ground inflation test again to find the balloon showed asymmetrical deployment and burst from the edge of the net with a differential pressure of 348 Pa. We consider it is due to the margin of the film along the circumferential direction, and proposed a gore shape which circumference length is kept as determined by the pumpkin shape of the balloon but setting meridian length longer than that. We developed a 10 m^{3} balloon with the gore design to find that the balloon deployed symmetrically and showed the burst pressure of 10,000 Pa. In 2016, we are going to develop a 2,000 m^{3} balloon with the gore design and perform its ground inflation test. In this paper, we are going to report its result with the sequence of the development.

  12. Shock instability in dissipative gases

    OpenAIRE

    Radulescu, Matei I.; Sirmas, Nick

    2011-01-01

    Previous experiments have revealed that shock waves in thermally relaxing gases, such as ionizing, dissociating and vibrationally excited gases, can become unstable. To date, the mechanism controlling this instability has not been resolved. Previous accounts of the D'yakov-Kontorovich instability, and Bethe-Zel'dovich-Thompson behaviour could not predict the experimentally observed instability. To address the mechanism controlling the instability, we study the propagation of shock waves in a ...

  13. Determination of membrane tension during balloon distension of intestine.

    Science.gov (United States)

    Gregersen, H; Kassab, G S; Fung, Y C

    2004-09-01

    During the last decades, it has become increasingly common to make balloons distension in visceral organs in vivo. In particular this is true for studies of gastrointestinal motor function and biomechanics. Balloon distension is often used for assessment of small intestinal compliance and tension based on Laplace's law for cylindrical pressure pipes. This commonly used law is valid only when the balloon-distended intestine is cylindrical. Experimentally, it is seen that the diameter of the balloon-distended intestine is not a constant, but variable in the axial direction. Hence, it is necessary to improve Laplace's law for intestinal investigation. In this paper we develop the framework for determination of the tension distribution in circumferential and longitudinal direction during balloon distension. When the radii of curvature are measured from a photograph of the intestinal profile, then the membrane stress resultants can be computed everywhere in the intestine in contact with the balloon from the equations of equilibrium. The experimental data were obtained from small intestinal segments from five pigs and three guinea pigs. Papaverine was injected before the animals were sacrificed to relax the intestinal smooth muscle. The segments were immersed in a bath with calcium-free Krebs solution with dextran and EGTA. A balloon was distended in the lumen with pressures up to 15 cmH2O in the pigs and 10 cmH2O in the guinea pigs and radii were measured along the z-axis. The tension in circumferential direction had its maximum approximately 25% away from the middle of the balloon. The circumferential tension was 2-3 times higher than the longitudinal tension. In conclusion when we know the shape of the intestine, we can compute the circumferential and longitudinal components of tension. The large variation in tensions along the z axis must be considered when performing balloon distension studies in the gastrointestinal tract for studying physiological and

  14. Complexity Analysis of Balloon Drawing for Rooted Trees

    CERN Document Server

    Lin, Chun-Cheng; Poon, Sheung-Hung; Fan, Jia-Hao

    2010-01-01

    In a balloon drawing of a tree, all the children under the same parent are placed on the circumference of the circle centered at their parent, and the radius of the circle centered at each node along any path from the root reflects the number of descendants associated with the node. Among various styles of tree drawings reported in the literature, the balloon drawing enjoys a desirable feature of displaying tree structures in a rather balanced fashion. For each internal node in a balloon drawing, the ray from the node to each of its children divides the wedge accommodating the subtree rooted at the child into two sub-wedges. Depending on whether the two sub-wedge angles are required to be identical or not, a balloon drawing can further be divided into two types: even sub-wedge and uneven sub-wedge types. In the most general case, for any internal node in the tree there are two dimensions of freedom that affect the quality of a balloon drawing: (1) altering the order in which the children of the node appear in...

  15. 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

  16. Restenosis following balloon dilation of benign esophageal stenosis

    Institute of Scientific and Technical Information of China (English)

    Ying-Sheng Cheng; Ming-Hua Li; Ren-Jie Yang; Hui-Zhen Zhang; Zai-Xian Ding; Qi-Xin Zhuang; Zhi-Ming Jiang; Ke-Zhong Shang

    2003-01-01

    AIM: To elucidate the mechanism of restenosis following balloon dilation of benign esophageal stenosis.METHODS: A total of 49 rats with esophageal stenosis were induced in 70 rats using 5 ml of 50 % sodium hydroxide solution and the double-balloon method, and an esophageal restenosis (RS) model was developed by esophageal stenosis using dilation of a percutaneous transluminal coronary angioplasty (PTCA) balloon catheter. These 49 rats were divided into two groups: rats with benign esophageal stricture caused by chemical burn only (control group, n=21) and rats with their esophageal stricture treated with balloon catheter dilation (experimental group, n=28). Imaging analysis and immunohistochemistry were used for both quantitative and qualitative analyses of esophageal stenosis and RS formation in the rats, respectively.RESULTS: Cross-sectional areas and perimeters of the esophageal mucosa layer, muscle layer, and the entire esophageal layers increased significantly in the experimental group compared with the control group. Proliferating cell nuclear antigen (PCNA) was expressed on the 5th day after dilation, and was still present at 1 month. Fibronectin (FN)was expressed on the 1st day after dilation, and was still present at 1 month.CONCLUSION: Expression of PCNA and FN plays an important role in RS after balloon dilation of benign esophageal stenosis.

  17. 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.

  18. Ballooning osteolysis in 71 failed total ankle arthroplasties.

    Science.gov (United States)

    Singh, Gurpal; Reichard, Theresa; Hameister, Rita; Awiszus, Friedemann; Schenk, Katja; Feuerstein, Bernd; Roessner, Albert; Lohmann, Christoph

    2016-08-01

    Background and purpose - Aseptic loosening is a major cause of failure in total ankle arthroplasty (TAA). In contrast to other total joint replacements, large periarticular cysts (ballooning osteolysis) have frequently been observed in this context. We investigated periprosthetic tissue responses in failed TAA, and performed an element analysis of retrieved tissues in failed TAA. Patients and methods - The study cohort consisted of 71 patients undergoing revision surgery for failed TAA, all with hydroxyapatite-coated implants. In addition, 5 patients undergoing primary TAA served as a control group. Radiologically, patients were classified into those with ballooning osteolysis and those without, according to defined criteria. Histomorphometric, immunohistochemical, and elemental analysis of tissues was performed. Von Kossa staining and digital microscopy was performed on all tissue samples. Results - Patients without ballooning osteolysis showed a generally higher expression of lymphocytes, and CD3+, CD11c+, CD20+, and CD68+ cells in a perivascular distribution, compared to diffuse expression. The odds of having ballooning osteolysis was 300 times higher in patients with calcium content >0.5 mg/g in periprosthetic tissue than in patients with calcium content ≤0.5 mg/g (p < 0.001). Interpretation - There have been very few studies investigating the pathomechanisms of failed TAA and the cause-effect nature of ballooning osteolysis in this context. Our data suggest that the hydroxyapatite coating of the implant may be a contributory factor.

  19. Development of Ultra-Thin Polyethylene Balloons for High Altitude Research upto Mesosphere

    Science.gov (United States)

    Kumar, B. Suneel; Nagendra, N.; Ojha, D. K.; Peter, G. Stalin; Vasudevan, R.; Anand, D.; Kulkarni, P. M.; Reddy, V. Anmi; Rao, T. V.; Sreenivasan, S.

    Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group at TIFR expressed the need for balloons capable of carrying the X-ray telescopes to altitudes up to 42 km, the balloon group initiated research and development work on indigenous balloon grade films in various thickness not only for the main experiment but also in parallel, took up the development of thin films in thickness range 5 to 6 μm for fabrication of sounding balloons required for probing the stratosphere up to 42 km as the regular 2000-gram rubber balloon ascents could not reach altitudes higher than 38 km. By the year 1999, total indigenization of sounding balloon manufacture was accomplished. The work on balloon grade ultra-thin polyethylene film in thickness range 2.8 to 3.8 μm for fabrication of balloons capable of penetrating mesosphere to meet the needs of user scientists working in the area of atmospheric dynamics commenced in 2011. Pursuant to the successful trials with 61,000-m3 balloon made of 3.8-μm Antrix film reaching stratopause (48 km) for the first time in the history of balloon facility in the year 2012, fine tuning of launch parameters like percentage free lift was carried out to take the same volume balloons to higher mesospheric altitudes. Three successful flights with a total suspended load of 10 kg using 61,000-m3 balloons were carried out in the month of January 2014 and all the three balloons crossed into the mesosphere reaching altitudes of over 51 km. All the balloons flown so far are closed system with no escape ducts. Balloon fabrication, development of launch hardware, flight control instruments and launch technique for these mesospheric balloon flights are discussed in this paper.

  20. High-n ballooning modes in highly elongated tokamaks

    International Nuclear Information System (INIS)

    An analytic study of stability against high-n ballooning modes is highly elongated axisymmetric plasmas is presented and compared with computational results. - From the equation for the marginal pressure gradient, it is found that local shear has an important effect on the stability of elongated plasmas, and that stability deteriorates through high elongation since the stabilizing effects of field line bending and local shear are reduced. The net contribution of the local shear to stability decreases with elongation for strong 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 βsub(p) less than unity but severely reduce the marginal beta for βsub(p) larger than unity. (author)

  1. Extrusion process optimization for toughness in balloon films

    Science.gov (United States)

    Cantor, K. M.; Harrison, I. R.

    1993-01-01

    An experimental optimization process for blown film extrusion is described and examined in terms of the effects of the technique on the toughness of balloon films. The optimization technique by Cantor (1990) is employed which involves the identification of key process variables including screw speed, nip speed, bubble diameter, and frost-line height for analysis to optimize the merit function. The procedure is employed in the extrusion of a low-density polyethylene polymer, and the resulting optimized materials are toughness- and puncture-tested. Balloon toughness is optimized in the analytical relationship, and the process parameters are modified to attain optimal toughness. The film produced is shown to have an average toughness of 24.5 MPa which is a good value for this key property of balloon materials for high-altitude flights.

  2. Ideal MHD Ballooning modes, shear flow and the stable continuum

    CERN Document Server

    Taylor, J B

    2012-01-01

    There is a well established theory of Ballooning modes in a toroidal plasma. The cornerstone of this is a local eigenvalue lambda on each magnetic surface - which also depends on the ballooning phase angle k. In stationary plasmas lambda(k) is required only near its maximum, but in rotating plasmas its average over k is required. Unfortunately in many case lambda(k) does not exist for some range of k, because the spectrum there contains only a stable continuum. This limits the application of the theory, and raises the important question of whether this "stable interval" gives rise to significant damping. This question is re-examined using a new, simplified, model - which leads to the conclusion that there is no appreciable damping at small shear flow. In particular, therefore, a small shear flow should not affect Ballooning mode stability boundaries.

  3. Ideal ballooning modes, shear flow and the stable continuum

    Science.gov (United States)

    Taylor, J. B.

    2012-11-01

    There is a well-established theory of ballooning modes in a toroidal plasma. The cornerstone of this is a local eigenvalue λ on each magnetic surface—which also depends on the ballooning phase angle k. In stationary plasmas, λ(k) is required only near its maximum, but in rotating plasmas its average over k is required. Unfortunately in many cases λ(k) does not exist for some range of k, because the spectrum there contains only a stable continuum. This limits the application of the theory, and raises the important question of whether this ‘stable interval’ gives rise to significant damping. This question is re-examined using a new, simplified, model—which leads to the conclusion that there is no appreciable damping at small shear flow. In particular, therefore, a small shear flow should not affect ballooning mode stability boundaries.

  4. Drug-Coated Balloons for Infrainguinal Peripheral Artery Disease.

    Science.gov (United States)

    Sethi, Sanjum S; Lee, Michael S

    2016-07-01

    Revascularization of infrainguinal peripheral artery disease has traditionally been accomplished via percutaneous transluminal angioplasty. However, long-term results have been hampered by high rates of restenosis. Along with the advent of stents, paclitaxel-coated balloons are an emerging therapeutic option for the invasive management of infrainguinal peripheral artery disease. Paclitaxel has been successful in inhibiting neointimal hyperplasia, the main mechanism for in-stent restenosis. Technological advances have facilitated the development of paclitaxel-coated balloons, which show promise in early trials for femoropopliteal stenosis relative to uncoated balloons. For infrapopliteal stenoses, the data remain scant and conflicted. Therefore, large-scale randomized clinical trials with long-term follow-up evaluating safety and effectiveness between various strategies need to be performed to determine the optimal invasive management strategy for infrainguinal peripheral artery disease. PMID:27342205

  5. Genetic instability in Gynecological Cancer

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qing-hua; ZHOU Hong-lin

    2003-01-01

    Defects of mismatch repair (MMR) genes also have beenidentified in many kinds of tumors. Loss of MMR functionhas been linked to genetic instability especially microsatelliteinstability that results in high mutation rate. In this review, wediscussed the microsatellite instability observed in thegynecological tumors. We also discussed defects in the DNAmismatch repair in these tumors and their correlation to themicrosatellite instability, as well as the gene mutations due tothe microsatellite instability in these tumors. From thesediscussion, we tried to understand the mechanism ofcarcinogenesis in gynecological tumors from the aspect ofgenetic instability due to mismatch repair defects.

  6. Cosmic ray driven instability

    International Nuclear Information System (INIS)

    The interaction between energetic charged particles and thermal plasma, which forms the basis of diffusive shock acceleration, leads also to interesting dynamical phenomena. For a compressional mode propagating in a system with homoeneous energetic particle pressure it is well known that friction with the energetic particles leads to damping. The linear theory of this effect has been analyzed in detail by Ptuskin. Not so obvious is that a non-uniform energetic particle pressure can in addition amplify compressional disturbances. If the pressure gradient is sufficiently steep this growth can dominate the frictional damping and lead to an instability. It is important to not that this effect results from the collective nature of the interaction between the energetic particles and the gas and is not connected with the Parker instability, nor with the resonant amplification of Alfven waves

  7. Instabilities in sensory processes

    Science.gov (United States)

    Balakrishnan, J.

    2014-07-01

    In any organism there are different kinds of sensory receptors for detecting the various, distinct stimuli through which its external environment may impinge upon it. These receptors convey these stimuli in different ways to an organism's information processing region enabling it to distinctly perceive the varied sensations and to respond to them. The behavior of cells and their response to stimuli may be captured through simple mathematical models employing regulatory feedback mechanisms. We argue that the sensory processes such as olfaction function optimally by operating in the close proximity of dynamical instabilities. In the case of coupled neurons, we point out that random disturbances and fluctuations can move their operating point close to certain dynamical instabilities triggering synchronous activity.

  8. Sessile Rayleigh drop instability

    Science.gov (United States)

    Steen, Paul; Bostwick, Josh

    2012-11-01

    Rayleigh (1879) determined the mode shapes and frequencies of the inviscid motion of a free drop held by surface tension. We study the inviscid motions of a sessile Rayleigh drop - a drop which rests on a planar solid and whose contact-line is free to move. Linear stability analysis gives the modes and frequencies of the droplet motions. In this talk, we focus on the ``walking instability,'' an unstable mode wherein the drop moves across a planar substrate in an inviscid rocking-like motion. The mode shape is non-axisymmetric. Although the experimental literature has hinted at such a mode, this is the first prediction from linear stability analysis, as far as we are aware. The ``walking instability'' of the drop converts energy stored in the liquid shape into the energy of liquid motion - which represents a heretofore unknown pathway of energy conversion of potentially wide significance for a broad range of applications.

  9. To sail the skies of Mars - Scientific ballooning on the red planet

    Science.gov (United States)

    Gaidos, Eric J.; Burke, James D.

    1988-01-01

    Balloons represent a novel approach to exploring the surface of Mars. One promising aerostat system incorporates a solar-powered balloon as a means of generating diurnally varying lift and so can 'hop' across the surface, obtaining detailed information at a large number of sites. Two important areas of research and testing are underway on solar balloon technology and balloon payload design. The solar balloon concept has been demonstrated on earth, but more work is needed on a 'flyable' version for Mars. Particular attention must be paid to radiation heat transfer and aerodynamic effects. A special 'snake' payload concept has been demonstrated that allows for balloon system traverses of the surface and provides a usable instrument platform. A balloon system of this type could obtain unique surface imaging and physical and chemical data. The flight of the balloon also provides in situ atmospheric boundary-layer and circulation measurements.

  10. Membranous duodenal stenosis: Initial experience with balloon dilatation in four children

    International Nuclear Information System (INIS)

    Introduction: We present a novel approach to the treatment of membranous duodenal stenosis (MDS). To our knowledge this is the first paper to describe balloon dilatation for this entity. Material and methods: Four children, 2 boys and 2 girls, aged between 8 and 28 days, underwent duodenal balloon dilatation. Balloon dilatation was performed under general anaesthesia using standard angiography balloons per os. Balloon diameters ranged from 6 to 14 mm. Results: All balloon dilatations were successful. None of the procedures showed procedural or post-procedural complications. None of the patients subsequently required surgical intervention. To date all children are doing well. Discussion: The initial experience with balloon dilation of MDS showed a 100% success rate, without procedural or post-procedural complications. The results obtained in this small group of patients suggest that the use of balloon dilatation in cases of MDS may be a safe technique that can be readily performed by an experienced interventional radiologist

  11. Balloon vetebroplasty with calcium phosphate cement augmentation for direct restoration of traumatic thoracolumbar vertebral fractures

    NARCIS (Netherlands)

    Verlaan, JJ; van Helden, WH; Oner, FC; Verbout, AJ; Dhert, WJA

    2002-01-01

    Study Design. A human cadaveric model was used to evaluate balloon vertebroplasty in traumatic vertebral fractures. Objectives. To assess the feasibility and safety of balloon vertebroplasty followed by calcium phosphate cement augmentation to prevent recurrent kyphosis. Summary of Background Data.

  12. The bar instability revisited

    OpenAIRE

    Chiodi, Filippo; Andreotti, Bruno; Claudin, Philippe

    2012-01-01

    The river bar instability is revisited, using a hydrodynamical model based on Reynolds averaged Navier-Stokes equations. The results are contrasted with the standard analysis based on shallow water Saint-Venant equations. We first show that the stability of both transverse modes (ripples) and of small wavelength inclined modes (bars) predicted by the Saint-Venant approach are artefacts of this hydrodynamical approximation. When using a more reliable hydrodynamical model, the dispersion relati...

  13. Near Space Lab-Rat Experimentation using Stratospheric Balloon

    Science.gov (United States)

    Buduru, Suneel Kumar; Reddy Vizapur, Anmi; Rao Tanneeru, Venkateswara; Trivedi, Dharmesh; Devarajan, Anand; Pandit Manikrao Kulkarni, MR..; Ojha, Devendra; Korra, Sakram; Neerudu, Nagendra; Seng, Lim; Godi, Stalin Peter

    2016-07-01

    First ever balloon borne lab-rat experiment up to near space stratospheric altitude levels carried out at TIFR Balloon Facility, Hydeabad using zero pressure balloons for the purpose of validating the life support system. A series of two balloon experiments conducted under joint collaboration with IN.Genius, Singapore in the year 2015. In these experiments, three lab-rats sent to stratosphere in a pressurized capsule designed to reach an altitude of 30 km by keeping constant pressure, temperature and maintained at a precise rate of oxygen supply inside the capsule. The first experiment conducted on 1 ^{st} February, 2015 with a total suspended weight of 225 kg. During the balloon ascent stage at 18 km altitude, sensors inside the capsule reported drastic drop in internal pressure while oxygen and temperatures maintained at correct levels resulted in premature fligt termination at 20.1 km. All the three lab-rats recovered without life due to the collapse of their lungs caused by the depressurization inside the capsule. The second experiment conducted on 14th March, 2015 using a newly developed capsule with rectification of depressurization fault by using improved sealing gaskets and hermitically sealed connectors for sending lab-rats again to stratosphere comprising a total suspended load of 122.3 kg. The balloon flight was terminated after reaching 29.5 km in 110 minutes and succesfully recovered all the three lab-rats alive. This paper focuses on lessons learnt of the development of the life support system as an integral pressurized vessel, flight control instrumentation, flight simulation tests using thermo-vaccum chamber with pre-flight operations.

  14. 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.

  15. Global magnetohydrodynamic instabilities in the L-2M stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, M. I., E-mail: mikhaylov-mi@nrcki.ru [National Research Centre Kurchatov Institute (Russian Federation); Shchepetov, S. V., E-mail: shch@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Nührenberg, C.; Nührenberg, J. [Max-Planck-Institut für Plasmaphysik (Germany)

    2015-12-15

    Analysis of global magnetohydrodynamic (MHD) instabilities in the L-2M stellarator (Prokhorov General Physics Institute, Russian Academy of Sciences) is presented. The properties of free-boundary equilibria states are outlined, the stability conditions for small-scale modes are briefly discussed, and the number of trapped particles is estimated. All the magnetic configurations under study are stable against ballooning modes. It is shown that global ideal internal MHD modes can be found reliably only in Mercier unstable plasmas. In plasma that is stable with respect to the Mercier criterion, global unstable modes that are localized in the vicinity of the free plasma boundary and are not associated with any rational magnetic surface inside the plasma (the so-called peeling modes) can be found. The radial structure of all perturbations under study is almost entirely determined by the poloidal coupling of harmonics. The results of calculations are compared with the available experimental data.

  16. Carpal instability nondissociative.

    Science.gov (United States)

    Wolfe, Scott W; Garcia-Elias, Marc; Kitay, Alison

    2012-09-01

    Carpal instability nondissociative (CIND) represents a spectrum of conditions characterized by kinematic dysfunction of the proximal carpal row, often associated with a clinical "clunk." CIND is manifested at the midcarpal and/or radiocarpal joints, and it is distinguished from carpal instability dissociative (CID) by the lack of disruption between bones within the same carpal row. There are four major subcategories of CIND: palmar, dorsal, combined, and adaptive. In palmar CIND, instability occurs across the entire proximal carpal row. When nonsurgical management fails, surgical options include arthroscopic thermal capsulorrhaphy, soft-tissue reconstruction, or limited radiocarpal or intercarpal fusions. In dorsal CIND, the capitate subluxates dorsally from its reduced resting position. Dorsal CIND usually responds to nonsurgical management; refractory cases respond to palmar ligament reefing and/or dorsal intercarpal capsulodesis. Combined CIND demonstrates signs of both palmar and dorsal CIND and can be treated with soft-tissue or bony procedures. In adaptive CIND, the volar carpal ligaments are slackened and are less capable of inducing the physiologic shift of the proximal carpal row from flexion into extension as the wrist ulnarly deviates. Treatment of choice is a corrective osteotomy to restore the normal volar tilt of the distal radius.

  17. BETTII: The Balloon Experimental Twin Telescope for Infrared Interferometry

    Science.gov (United States)

    Rinehart, Stephen

    2011-01-01

    Astronomical studies at infrared wavelengths have dramatically improved our understanding the universe. The relatively low angular resolution of these missions, however, is insufficient to resolve the physical scale on which mid-to far-infrared emission arises. We will build the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII),8oeight-meter Michelson interferometer to fly on a high-altitude balloon. BETTII's spectral-spatial capability, provided by an instrument using double-Fourier techniques, will address key questions about the nature of disks io young star clusters and active galactic nuclei and the envelopes of evolved stars. BETTII will also lay the technological groundwork for future space interferometers.

  18. The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII)

    Science.gov (United States)

    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. BETTII uses a double-Fourier Michelson interferometer to simultaneously obtain spatial and spectral information on science targets; the long baseline provides subarcsecond angular resolution, a capability unmatched by other far-infrared facilities. Here, we present key aspects of the overall design of the mission and provide an overview of the current status of the project. We also discuss briefly the implications of this experiment for future space-based far-infrared interferometers.

  19. Emerging Stent and Balloon Technologies in the Femoropopliteal Arteries

    Directory of Open Access Journals (Sweden)

    Georgios Pastromas

    2014-01-01

    Full Text Available Endovascular procedures for the management of the superficial femoral (SFA and popliteal artery disease are increasingly common. Over the past decade, several stent technologies have been established which may offer new options for improved clinical outcomes. This paper reviews the current evidence for SFA and popliteal artery angioplasty and stenting, with a focus on randomized trials and registries of nitinol self-expanding stents, drug-eluting stents, dug-coated balloons, and covered stent-grafts. We also highlight the limitations of the currently available data and the future routes in peripheral arterial disease (PAD stent and balloon technology.

  20. Cosmic ray abundance measurements with the CAKE balloon experiment

    CERN Document Server

    Cecchini, S; Giacomelli, G; Manzoor, S; Medinaceli, E; Patrizii, L; Togo, V

    2005-01-01

    We present the results from the CAKE (Cosmic Abundance below Knee Energy) balloon experiment which uses nuclear track detectors. The final experiment goal is the determination of the charge spectrum of CR nuclei with Z $>$ 30 in the primary cosmic radiation. The detector, which has a geometric acceptance of $\\sim$ 1.7 m$^2$sr, was exposed in a trans-mediterranean stratospheric balloon flight. Calibrations of the detectors used (CR39 and Lexan), scanning strategies and algorithms for tracking particles in an automatic mode are presented. The present status of the results is discussed

  1. Testing in a stratospheric balloon of a semiconductor detector altimeter

    International Nuclear Information System (INIS)

    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)

  2. Balloon-Borne System Would Aim Instrument Toward Sun

    Science.gov (United States)

    Polites, M. E.

    1992-01-01

    Proposed system including digital control computer, control sensors, and control actuators aims telescope or other balloon-borne instrument toward Sun. Pointing system and instrument flown on gondola, suspended from balloon. System includes reaction wheel, which applies azimuthal control torques to gondola, and torque motor to apply low-frequency azimuthal torques between gondola and cable. Three single-axis rate gyroscopes measure yaw, pitch, and roll. Inclinometer measures roll angle. Two-axis Sun sensor measures deviation, in yaw and pitch, of attitude of instrument from line to apparent center of Sun. System provides initial coarse pointing, then maintains fine pointing.

  3. Polymer blends for LDB applications. [Long Duration Ballooning

    Science.gov (United States)

    Lichkus, Andrew M.; Harrison, Ian R.

    1991-01-01

    A series of LCP/PE blends have been studied to determine the potential of such systems to produce a high modulus balloon film material which retains the balloon fabrication and low temperature flight advantages of the current PE films. Blown films of blends of 5 and 15 percent LCP in PE have been produced which show a 28 percent enhancement in modulus over the neat PE matrix. These results are substantially lower than anticipated and are explained in terms of the LCP reinforcement aspect ratio and fibril diameter.

  4. Shoulder instability; Schultergelenkinstabilitaet

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, J.; Imhof, H. [Abteilung Osteoradiologie, Univ.-Klinik fuer Radiodiagnostik Wien (Austria)

    2004-06-01

    Shoulder instability is a common clinical feature leading to recurrent pain and limitated range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging. (orig.) [German] Die Schultergelenkinstabilitaet ist haeufig fuer wiederholt auftretende Schmerzen sowie eine eingeschraenkte Beweglichkeit im Glenohumeralgelenk verantwortlich. Sie kann als Folge eines vorangegangenen Traumas, einer generellen Hyperlaxitaet oder infolge wiederholter Mikrotraumen entstehen. Die Differenzierung zwischen traumatischer und atraumatischer Form der Gelenkinstabilitaet erfordert eine sorgfaeltige Anamnese und eine genaue klinische Untersuchung. Die Gelelenklaxitaet als Differenzialdiagnose muss von der echten Instabilitaet unterschieden werden, die Instabilitaet wird dann im Rahmen des klinischen Status nach Grad und Richtung der glenohumeralen Translation unterteilt. Zur Diagnose knoecherner Laesionen werden das konventionelle Roentgen sowie die CT herangezogen. MRT sowie MR-Arthrographie dienen zur Detektion

  5. Long-term follow-up after embolization of pulmonary arteriovenous malformations with detachable silicone balloons

    DEFF Research Database (Denmark)

    Andersen, Poul Erik; Kjeldsen, Anette D

    2007-01-01

    ) 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...

  6. Three dimensional intravascular ultrasonic assessment of the local mechanism of restenosis after balloon angioplasty

    NARCIS (Netherlands)

    M.A. Costa (Marco); P.J. de Feyter (Pim); K. Kozuma (Ken); A.L. Gaster; M. Sabaté (Manel); I.P. Kay (Ian Patrick); J.M.R. Ligthart (Jürgen); P. Thayssen; M.J.B.M. van den Brand (Marcel); P.W.J.C. Serruys (Patrick); D.P. Foley (David); W.J. van der Giessen (Wim)

    2001-01-01

    textabstractOBJECTIVE: To assess the mechanism of restenosis after balloon angioplasty. DESIGN: Prospective study. PATIENTS: 13 patients treated with balloon angioplasty. INTERVENTIONS: 111 coronary subsegments (2 mm each) were analysed after balloon angioplasty and at a six month follow up using th

  7. Study of aspect ratio effects on MHD instabilities

    International Nuclear Information System (INIS)

    Full text: Aspect ratio affects kinetic instabilities in many ways. In this paper we describe explicit aspect ratio scaling studies of kinetic instabilities using the NSTX and DIII- D devices and introduce new theoretical work on the general kinetic physics of KBM, TAE, CAE with applications on NSTX. The National Spherical Torus Experiment (NSTX) and the DIII-D tokamak are nearly ideal for an Alfven mode similarity experiment, with similar neutral beams, fast-ion to Alfven speed, fast-ion pressure, and shape of the plasma, but the major radius differs by a factor of two. A similarity study of the toroidal Alfven mode (TAE) shows that the most unstable toroidal mode number scales as expected, supporting an expectation of a 'sea' of unstable modes in a reactor. Alfvenic instabilities with frequencies that chirp rapidly are common in NSTX but rare in DIII-D. Efforts to understand this difference in terms of the hole-clump theory of Berk and Breizman are reported. Compressional Alfven modes (CAE) on NSTX have the frequency scaling, polarization, dependence on the fast-ion distribution function, and low frequency limit qualitatively consistent with CAE theory. Experiments are planned to compare the stability limits on DIII-D with the NSTX stability limits, with the aim of determining if CAE will be excited by alphas in a reactor. The ballooning instability results from the release of free energy of non- uniform pressure that has a gradient in the same direction as the magnetic field curvature. We show that the combined kinetic effect of trapped electron dynamics and ion Larmor radii produces a large parallel electric field and hence a parallel current that greatly enhances the stabilizing effect of field line tension. We are grateful to the NSTX and DIII-D teams. (author)

  8. [Intra-graft balloon pumping--a clinical case report].

    Science.gov (United States)

    Nagata, M; Tashiro, T; Tanaka, K; Haruta, Y; Todo, K

    1991-12-01

    A 29-year-old female underwent tube graft replacement of distal aortic arch and descending aorta for dissecting aneurysm. After 42 minutes of aortic cross-clamping the patient was initially weaned satisfactorily from cardiopulmonary bypass (CPB). However, cardiac arrhythmia and cardiac arrest necessitated reestablishment of CPB. Electro-cardiography showed inferior myocardial infarction. To wean CPB intraaortic balloon pumping (IABP) was mandatory. But because of dissecting aortic aneurysm IABP in conventional method was contra-indicated. Intra graft balloon pumping (IGBP) was initiated while the patient was on full CPB. A low-porosity woven Dacron tube graft (22 mm) was anastomosed end-to-side to ascending aorta. A balloon was inserted into the tube graft to establish IGBP. This IGBP provided effective circulatory assist. The patient was weaned from CPB 1 hours after reestablishment of IGBP. Postoperative course was stable. The patient was returned to the operating room for removal of the balloon 3 days postoperatively. We reported the case for whom IGBP was effective. IGBP was effective circulatory support for the patient when conventional use of IABP was contra-indicated. PMID:1774515

  9. Complications of flow-directed balloon-tipped catheters.

    Science.gov (United States)

    Smart, F W; Husserl, F E

    1990-01-01

    Acute or short-term complications following the use of flow-directed balloon-tipped catheters are well recognized. Long-term sequelae are rarely reported. We report herein an early complication of pulmonary arterial rupture with infarction followed by the delayed development of a pulmonary arterial aneurysm.

  10. Balloon atrial septostomy under echocardiographic guide: case series

    Directory of Open Access Journals (Sweden)

    SM Meraji

    2012-12-01

    Full Text Available Background: Balloon atrial septostomy is an emergent procedure in pediatric cardiology. Nowadays, most patients in need of the procedure have acceptable outcomes after surgical repair. Thus, it is important to perform this procedure as safe as possible. By performing early arterial switch operation and prostaglandin infusion, the rate of balloon atrial septostomy has markedly decreased. However, not all centers performing early arterial switch repairs have abandoned atrial septostomy, even in patients who respond favorably to prostaglandin infusion.Case presentation: In total, eight 1- to 15-day old term neonates admitted in Shahid Rajaee Heart Center in Tehran, Iran from October 2009 to February 2011, with congenital heart diseases were scheduled for balloon atrial septostomy. In six cases the procedure was done exclusively under echocardiographic guidance and in two cases with the help of fluoroscopy. Success was defined as the creation of an atrial septal defect with a diameter equal to or more than 5 mm and ample mobility of its margins.Results: Male sex was predominant (87% and the mean age of the neonates was six days. The diagnosis in all cases was simple transposition of great arteries. The procedure was successful in all patients with any cardiovascular complication.Conclusion: Balloon atrial septostomy is an emergent procedure that can be done safely and effectively under echocardiographic guidance. According to the feasibility of this technique it could be performed fast, safe and effective at bedside, avoiding patient transportation to hemodynamic laboratory or referral center.

  11. 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.

  12. Scientific Ballooning Technologies Workshop STO-2 Thermal Design and Analysis

    Science.gov (United States)

    Ferguson, Doug

    2016-01-01

    The heritage thermal model for the full STO-2 (Stratospheric Terahertz Observatory II), vehicle has been updated to model the CSBF (Columbia Scientific Balloon Facility) SIP-14 (Scientific Instrument Package) in detail. Analysis of this model has been performed for the Antarctica FY2017 launch season. Model temperature predictions are compared to previous results from STO-2 review documents.

  13. Investigating obscure gastrointestinal bleeding : capsule endoscopy or double balloon enteroscopy?

    NARCIS (Netherlands)

    Westerhof, J.; Weersma, R. K.; Koornstra, J. J.

    2009-01-01

    The possibility to visualise the small bowel has dramatically improved with the introduction of capsule endoscopy (CE) and double balloon enteroscopy (DBE). CE and DBE have become standard practice in investigating suspected diseases of the small bowel. An important reason to perform small bowel inv

  14. Hot Air Balloon: An Unusual Cause of Multicasualty Trauma Incident.

    Science.gov (United States)

    Persoz, Marc-Olivier; Dami, Fabrice; Ciavatta, Ettore; Vallotton, Laurent; Albrecht, Roland; Carron, Pierre-Nicolas

    2016-01-01

    Hot air balloon incidents are few and far between compared with the total number of flights. Nevertheless, hot air balloon incidents may produce severe trauma involving several patients and are linked to significant mortality. The prehospital management of injured patients starts after having secured potential surrounding dangers, such as fire or explosion. In the context of a rescue by helicopter, close attention must be paid to potential obstacles, like trees or electrical wires, and the risk of aspiration of the balloon envelope into the rotor. Patients involved in such incidents are often split up in a closed perimeter around the crash point. The severity of the trauma depends essentially on the height of the fall. The most frequent traumatic lesions involve fractures of the lower limbs, the spine, and the pelvis as well as severe burns caused by the balloon fire. Because of the number of patients present, an initial triage is usually required at the site. The use of rescue helicopters can be helpful. They can perform aerial reconnaissance, provide on-site high-level resources, enable access to the patients even in hostile environments, and quickly transport them to trauma center hospitals. PMID:27255882

  15. Latex micro-balloon pumping in centrifugal microfluidic platforms.

    Science.gov (United States)

    Aeinehvand, Mohammad Mahdi; Ibrahim, Fatimah; Harun, Sulaiman Wadi; Al-Faqheri, Wisam; Thio, Tzer Hwai Gilbert; Kazemzadeh, Amin; Madou, Marc

    2014-03-01

    Centrifugal microfluidic platforms have emerged as point-of-care diagnostic tools. However, the unidirectional nature of the centrifugal force limits the available space for multi-step processes on a single microfluidic disc. To overcome this limitation, a passive pneumatic pumping method actuated at high rotational speeds has been previously proposed to pump liquid against the centrifugal force. In this paper, a novel micro-balloon pumping method that relies on elastic energy stored in a latex membrane is introduced. It operates at low rotational speeds and pumps a larger volume of liquid towards the centre of the disc. Two different micro-balloon pumping mechanisms have been designed to study the pump performance at a range of rotational frequencies from 0 to 1500 rpm. The behaviour of the micro-balloon pump on the centrifugal microfluidic platforms has been theoretically analysed and compared with the experimental data. The experimental data show that the developed pumping method dramatically decreases the required rotational speed to pump liquid compared to the previously developed pneumatic pumping methods. It also shows that within a range of rotational speed, a desirable volume of liquid can be stored and pumped by adjusting the size of the micro-balloon.

  16. 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.

  17. [Expansion dilatation balloons for cervical ripening in obstetric practice].

    Science.gov (United States)

    Ducarme, G; Grange, J; Vital, M

    2016-02-01

    During recent decades, mechanical devices have been substituted by pharmacological methods. Their place in the therapeutic arsenal remains important with a renewed obstetrical interest for these devices. Due to a lack of data they are still not recommended as first-line. This review thus attempted to examine the use of expansion dilatation balloons (Foley catheter and double-balloons) to analyze their effectiveness in case of native uterus and previous cesarean section. Twenty-seven clinical trials had compared balloons catheter and prostaglandins in patients without a history of uterine scar. The risk of cesarean section did not differ. Mechanical methods seemed to be more effective in achieving delivery within 24hours, with fewer episodes of excessive uterine contractions, but they necessitated more oxytocin during labor. Ten clinical trials analyzed dilatation balloons in patients with previous cesarean section. More than 70% women had favorable cervical ripening (Bishop score>6), and vaginal delivery was reported between 35 and 70% of patients. The risk of uterine rupture was low between 0.64 and 0.72%, with neither increased risk of severe neonatal and maternal morbidity nor increased risk of infectious morbidity. Mechanical methods are effective and safe for third trimester cervical ripening, mainly in women with previous cesarean section. Potential advantages may include wide availability and reduction of some of the side effects. PMID:26774842

  18. Stability of infernal and ballooning modes in advanced tokamak scenarios

    NARCIS (Netherlands)

    Holties, H. A.; Huysmans, G. T. A.; Goedbloed, J. P.; Kerner, W.; Parail, V.V.; Soldner, F. X.

    1996-01-01

    A numerical parameter study has been performed in order to find MHD stable operating regimes for advanced tokamak experiments In this study we have concentrated on internal modes. Ballooning stability and stability with respect to infernal modes are considered. The calculations confirm that pressure

  19. 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.

  20. Balloon-assisted coiling through a 5-French system

    International Nuclear Information System (INIS)

    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.)

  1. Using Hydrogen Balloons to Display Metal Ion Spectra

    Science.gov (United States)

    Maynard, James H.

    2008-01-01

    We have optimized a procedure for igniting hydrogen-filled balloons containing metal salts to obtain the brightest possible flash while minimizing the quantity of airborne combustion products. We report air quality measurements in a lecture hall immediately after the demonstration. While we recommend that this demonstration be done outdoors or in…

  2. Genome instability and aging.

    Science.gov (United States)

    Vijg, Jan; Suh, Yousin

    2013-01-01

    Genome instability has long been implicated as the main causal factor in aging. Somatic cells are continuously exposed to various sources of DNA damage, from reactive oxygen species to UV radiation to environmental mutagens. To cope with the tens of thousands of chemical lesions introduced into the genome of a typical cell each day, a complex network of genome maintenance systems acts to remove damage and restore the correct base pair sequence. Occasionally, however, repair is erroneous, and such errors, as well as the occasional failure to correctly replicate the genome during cell division, are the basis for mutations and epimutations. There is now ample evidence that mutations accumulate in various organs and tissues of higher animals, including humans, mice, and flies. What is not known, however, is whether the frequency of these random changes is sufficient to cause the phenotypic effects generally associated with aging. The exception is cancer, an age-related disease caused by the accumulation of mutations and epimutations. Here, we first review current concepts regarding the relationship between DNA damage, repair, and mutation, as well as the data regarding genome alterations as a function of age. We then describe a model for how randomly induced DNA sequence and epigenomic variants in the somatic genomes of animals can result in functional decline and disease in old age. Finally, we discuss the genetics of genome instability in relation to longevity to address the importance of alterations in the somatic genome as a causal factor in aging and to underscore the opportunities provided by genetic approaches to develop interventions that attenuate genome instability, reduce disease risk, and increase life span. PMID:23398157

  3. Booming Dune Instability

    Science.gov (United States)

    Andreotti, B.; Bonneau, L.

    2009-12-01

    Sand avalanches flowing down the leeward face of some desert dunes spontaneously produce a loud sound with a characteristic vibrato around a well-defined frequency, a phenomenon called the “song of dunes.” Here, we show through theory that a homogenous granular surface flow is linearly unstable towards growing elastic waves when a localized shear band forms at the interface between the avalanche and the static part of the dune. We unravel the nature of the acoustic amplifying mechanism at the origin of this booming instability. The dispersion relation and the shape of the most unstable modes are computed and compared to field measurements.

  4. Structural and Material Instability

    DEFF Research Database (Denmark)

    Cifuentes, Gustavo Cifuentes

    This work is a small contribution to the general problem of structural and material instability. In this work, the main subject is the analysis of cracking and failure of structural elements made from quasi-brittle materials like concrete. The analysis is made using the finite element method. Three....... Numerical problems associated with the use of elements with embedded cracks based on the extended finite element method are presented in the next part of this work. And an alternative procedure is used in order to successfully remove these numerical problems. In the final part of this work, a computer...

  5. Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

    Science.gov (United States)

    Kogut, Alan; James, Bryan; Fixsen, Dale

    2013-01-01

    Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity. The solution is to separate the functions of cryogen storage and in-flight thermal isolation, utilizing the unique physical conditions at balloon altitudes. Conventional dewars are launched cold: the vacuum walls necessary for thermal isolation must also withstand the pressure gradient at sea level and are correspondingly thick and heavy. The pressure at 40 km is less than 0.3% of sea level: a dewar designed for use only at 40 km can use ultra thin walls to achieve significant reductions in mass. This innovation concerns new construction and operational techniques to produce a lightweight liquid helium bucket dewar. The dewar is intended for use on high-altitude balloon payloads. The mass is low enough to allow a large (3-to-5-meter) diameter dewar to fly at altitudes above 35 km on conventional scientific research balloons without exceeding the lift capability of the balloon. The lightweight dewar has thin (250- micron) stainless steel walls. The walls are too thin to support the pressure gradient at sea level: the dewar launches warm with the vacuum space vented continuously during ascent to eliminate any pressure gradient across the walls. A commercial 500-liter storage dewar maintains a reservoir of liquid helium within a minimal (hence low mass) volume. Once a 40-km altitude is reached, the valve venting the vacuum space of the bucket dewar is closed to seal the vacuum space. A vacuum pump then

  6. Modulational instability of nematic phase

    Indian Academy of Sciences (India)

    T Mithun; K Porsezian

    2014-02-01

    We numerically observe the effect of homogeneous magnetic field on the modulationally stable case of polar phase in = 2 spinor Bose–Einstein condensates (BECs). Also we investigate the modulational instability of uniaxial and biaxial (BN) states of polar phase. Our observations show that the magnetic field triggers the modulational instability and demonstrate that irrespective of the magnetic field effect the uniaxial and biaxial nematic phases show modulational instability.

  7. Instability in Shocked Granular Gases

    OpenAIRE

    Sirmas, Nick; Falle, Sam; Radulescu, Matei

    2013-01-01

    Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by performing discrete-particle simulations of inelastic media undergoing shock compression. By allowing finite dissipation within the shock wave, instability manifests itself as distinctive high density non-uniformities and convective rolls within the shock structur...

  8. Summary of longitudinal instabilities workshop

    International Nuclear Information System (INIS)

    A five-day ISABELLE workshop on longitudinal instabilities was held at BNL, August 9--13, 1976. Heavy emphasis was put on single bunched beam instabilities in the microwave region extending above the cut-off frequency of the ISABELLE vacuum chamber. A discussion is given of the mechanism governing the instability, and calculations as well as measurements of the longitudinal coupling impedances in the ISABELLE rings are described

  9. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur. If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavity...... triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays...

  10. Odontoid balloon kyphoplasty associated with screw fixation for Type II fracture in 2 elderly patients.

    Science.gov (United States)

    Terreaux, Luc; Loubersac, Thomas; Hamel, Olivier; Bord, Eric; Robert, Roger; Buffenoir, Kevin

    2015-03-01

    Anterior screw fixation is a well-recognized technique that is used to stabilize Type IIB fractures of the odontoid process in the elderly. However, advanced age and osteoporosis are 2 risk factors for pseudarthrosis. Kyphoplasty has been described in the treatment of lytic lesions in C-2. The authors decided to combine these 2 techniques in the treatment of unstable fractures of the odontoid. Two approximately 90-year-old patients were treated for this type of fracture. Instability was demonstrated on dynamic radiography in one patient, and the fracture was seen on static radiography in the other. Clinical parameters, pain, range of motion, 36-Item Short Form Health Survey (SF-36) score (for the first patient), and radiological examinations (CT scans and dynamic radiographs) were studied both before and after surgery. After inflating the balloon both above and below the fracture line, the authors applied a high-viscosity polymethylmethacrylate cement. Some minor leakage of cement was noted in both cases but proved to be harmless. The screws were correctly positioned. The clinical result was excellent, both in terms of pain relief and in the fact that there was no reduction in the SF-36 score. The range of motion remained the same. A follow-up CT scan obtained 1 year later in one of the patients showed no evidence of change in the materials used, and the dynamic radiographs showed no instability. This combination of kyphoplasty and anterior screw fixation of the odontoid seems to be an interesting technique in osteoporotic Type IIB fractures of the odontoid process in the elderly, with good results both clinically and radiologically.

  11. [Aspirin suppresses microsatellite instability].

    Science.gov (United States)

    Wallinger, S; Dietmaier, W; Beyser, K; Bocker, T; Hofstädter, F; Fishel, R; Rüschoff, J

    1999-01-01

    Nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit cancer preventive effects and have been shown to induce regression of adenomas in FAP patients. In order to elucidate the probable underlying mechanism, the effect of NSAIDs on mismatch repair related microsatellite instability was investigated. Six colorectal cancer cell lines all but one deficient for human mismatch repair (MMR) genes were examined for microsatellite instability (MSI) prior and after treatment with Aspirin or Sulindac. For rapid in vitro analysis of MSI a microcloning assay was developed by combining Laser microdissection and random (PEP-) PCR prior to specific MSI-PCR. Effects of NSAIDs on cell cycle and apoptosis were systematically investigated by using flow cytometry and cell-sorting. MSI frequency in cells deficient of MMR genes (hMSH2, hMLH1, hMSH6) was markedly reduced after long-term (> 10 weeks) NSAID treatment. This effect was reversible, time- and concentration dependent. However, in the hPMS2 deficient endometrial cancer cell line (HEC-1-A) the MSI phenotype kept unchanged. According to cell sorting, non-apoptotic cells were stable and apoptotic cells were unstable. These results suggest that aspirin/sulindac induces a genetic selection for microsatellite stability in a subset of MMR-deficient cells and may thus provide an effective prophylactic therapy for HNPCC related colorectal carcinomas.

  12. Libration driven multipolar instabilities

    CERN Document Server

    Cébron, David; Herreman, Wietze

    2014-01-01

    We consider rotating flows in non-axisymmetric enclosures that are driven by libration, i.e. by a small periodic modulation of the rotation rate. Thanks to its simplicity, this model is relevant to various contexts, from industrial containers (with small oscillations of the rotation rate) to fluid layers of terrestial planets (with length-of-day variations). Assuming a multipolar $n$-fold boundary deformation, we first obtain the two-dimensional basic flow. We then perform a short-wavelength local stability analysis of the basic flow, showing that an instability may occur in three dimensions. We christen it the Libration Driven Multipolar Instability (LDMI). The growth rates of the LDMI are computed by a Floquet analysis in a systematic way, and compared to analytical expressions obtained by perturbation methods. We then focus on the simplest geometry allowing the LDMI, a librating deformed cylinder. To take into account viscous and confinement effects, we perform a global stability analysis, which shows that...

  13. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); P.P.T. de Jaegere (Peter); F. Kiemeneij (Ferdinand); C.M. Miguel (Carlos); W.R. Rutsch (Wolfgang); G.R. Heyndrickx (Guy); H.U. Emanuelsson (Hakan); J. Marco (Jean); V.M.G. Legrand (Victor); P.H. Materne (Phillipe); J.A. Belardi (Jorge); U. Sigwart (Ulrich); A. Colombo (Antonio); J-J. Goy (Jean-Jacques); P.A. van den Heuvel (Paul); J. Delcan; M-A.M. Morel (Marie-Angèle)

    1994-01-01

    textabstractBalloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical outcomes as c

  14. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease.

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); P.P.T. de Jaegere (Peter); F. Kiemeneij (Ferdinand); C.M. Miguel (Carlos); W.R. Rutsch (Wolfgang); G.R. Heyndrickx (Guy); H.U. Emanuelsson (Hakan); J. Marco (Jean); V.M.G. Legrand (Victor); P.H. Materne (Phillipe); J.A. Belardi (Jorge); U. Sigwart (Ulrich); A. Colombo (Antonio); J-J. Goy (Jean-Jacques); P. van den Heuvel; J. Delcan; M-A.M. Morel (Marie-Angèle)

    1994-01-01

    textabstractBACKGROUND. Balloon-expandable coronary-artery stents were developed to prevent coronary restenosis after coronary angioplasty. These devices hold coronary vessels open at sites that have been dilated. However, it is unknown whether stenting improves long-term angiographic and clinical o

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

    International Nuclear Information System (INIS)

    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

  16. Using High Resolution Balloon Photography to Provide Topographic Data

    Science.gov (United States)

    Russell, K.; Bauer, T.

    2009-12-01

    For site-scale projects, the Bureau of Reclamation has used low altitude balloon photogrammetry to obtain high-resolution photographs and detailed topographic information. These data are collected in a fraction of the time and effort it would take to obtain a similar level of detail using traditional methods. This is accomplished at a significantly reduced cost compared to flying LiDAR or aerial photography, which can be prohibitively expensive for small or medium scale projects. Low altitude balloon photogrammetry is a process where overlapping photographs and ground survey control points are input into a photogrammetry software program (AdamTechnology 3DM Analyst Mine Mapping Suite) to produce orthophotographs and digital terrain model (DTM) elevation points. To acquire the photos a digital camera is attached to an 8-foot diameter helium balloon. The balloon is tethered and flown above the location of interest. The camera is controlled remotely while a live image is transmitted to a receiver on the ground. Ground survey control is established by using GPS equipment to survey ground targets placed within the area to be photographed. There are limitations to the process. Data collection is very weather dependent; too much wind causes the balloon to be unstable. Site conditions also determine the feasibility: power lines, trees, and steep embankments can cause difficulties maneuvering the balloon. Although some of the photographs show the underwater portion of the channel; there is little agreement between GPS points and the processed DTM elevations in the channel. The balloon has been used to survey large woody debris (LWD) structures and channel morphology in the Middle Fork John Day River (central Oregon) and monitoring debris after the removal of Chiloquin Dam (Sprague River, southern Oregon). Seventeen LWD structures were installed on the Middle Fork John Day River near John Day, OR in 2007 and 2008 to provide aquatic habitat. Balloon photos were obtained in

  17. 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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Eldon, D.; Boivin, R. L.; Groebner, R. J.; Osborne, T. H.; Snyder, P. B.; Turnbull, A. D.; Tynan, G. R.; Boedo, J. A.; Burrell, K. H.; Kolemen, E.; Schmitz, L.; Wilson, H. R.

    2015-05-01

    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.

  20. Instabilities, turbulence and transport in a magnetized plasma

    International Nuclear Information System (INIS)

    The purpose of this work is to introduce the main processes that occur in a magnetized plasma. During the last 2 decades, the understanding of turbulence has made great progress but analytical formulas and simulations are far to produce reliable predictions. The values of transport coefficients in a tokamak plasma exceed by far those predicted by the theory of collisional transport. This phenomenon is called abnormal transport and might be due to plasma fluctuations. An estimation of turbulent fluxes derived from the levels of fluctuations, is proposed. A flow description of plasma allows the understanding of most micro-instabilities. The ballooning representation deals with instabilities in a toric geometry. 3 factors play an important role to stabilize plasmas: density pinch, magnetic shear and speed shear. The flow model of plasma gives an erroneous value for the stability threshold, this is due to a bad description of the resonant interaction between wave and particle. As for dynamics, flow models can be improved by adding dissipative terms so that the linear response nears the kinetic response. The kinetic approach is more accurate but is complex because of the great number of dimensions involved. (A.C.)

  1. Cinerama sickness and postural instability

    NARCIS (Netherlands)

    Bos, J.E.; Ledegang, W.D.; Lubeck, A.J.A.; Stins, J.F.

    2013-01-01

    Motion sickness symptoms and increased postural instability induced by motion pictures have been reported in a laboratory, but not in a real cinema. We, therefore, carried out an observational study recording sickness severity and postural instability in 19 subjects before, immediately and 45 min af

  2. Microsatellite instability in bladder cancer

    DEFF Research Database (Denmark)

    Gonzalez-Zulueta, M; Ruppert, J M; Tokino, K;

    1993-01-01

    Somatic instability at microsatellite repeats was detected in 6 of 200 transitional cell carcinomas of the bladder. Instabilities were apparent as changes in (GT)n repeat lengths on human chromosome 9 for four tumors and as alterations in a (CAG)n repeat in the androgen receptor gene on the X...

  3. Cohabitation and Children's Family Instability

    Science.gov (United States)

    Kelly Raley, R.; Wildsmith, Elizabeth

    2004-01-01

    This study estimates how much children's family instability is missed when we do not count transitions into and out of cohabitation, and examines early life course trajectories of children to see whether children who experience maternal cohabitation face more family instability than children who do not. Using data from the 1995 National Survey of…

  4. Genome instability in Alzheimer disease

    DEFF Research Database (Denmark)

    Hou, Yujun; Song, Hyundong; Croteau, Deborah L;

    2016-01-01

    to the development of noninvasive treatment strategies. Further investigations into the molecular mechanisms connecting DNA damage to AD pathology may help to develop novel treatment strategies for this debilitating disease. Here we provide an overview of the role of genome instability and DNA repair deficiency...... in AD pathology and discuss research strategies that include genome instability as a component....

  5. Plateau Rayleigh instability simulation.

    Science.gov (United States)

    Mead-Hunter, Ryan; King, Andrew J C; Mullins, Benjamin J

    2012-05-01

    The well-known phenomena of Plateau-Rayleigh instability has been simulated using computational fluid dynamics (CFD). The breakup of a liquid film into an array of droplets on a cylindrical element was simulated using a volume-of-fluid (VOF) solver and compared to experimental observations and existing theory. It is demonstrated that the VOF method can correctly predict the breakup of thins films into an array of either axisymmetric droplets or clam-shell droplets, depending on the surface energy. The existence of unrealistically large films is precluded. Droplet spacing was found to show reasonable agreement with theory. Droplet motion and displacement under fluid flow was also examined and compared to that in previous studies. It was found that the presence of air flow around the droplet does not influence the stable film thickness; however, it reduces the time required for droplet formation. Novel relationships for droplet displacement were derived from the results. PMID:22512475

  6. Instability and Information

    CERN Document Server

    Patzelt, Felix

    2015-01-01

    Many complex systems exhibit extreme events far more often than expected for a normal distribution. This work examines how self-similar bursts of activity across several orders of magnitude can emerge from first principles in systems that adapt to information. Surprising connections are found between two apparently unrelated research topics: hand-eye coordination in balancing tasks and speculative trading in financial markets. Seemingly paradoxically, locally minimising fluctuations can increase a dynamical system's sensitivity to unpredictable perturbations and thereby facilitate global catastrophes. This general principle is studied in several domain-specific models and in behavioural experiments. It explains many findings in both fields and resolves an apparent antinomy: the coexistence of stabilising control or market efficiency and perpetual instabilities resembling critical phenomena in physical systems.

  7. The bar instability revisited

    CERN Document Server

    Chiodi, Filippo; Claudin, Philippe

    2012-01-01

    The river bar instability is revisited, using a hydrodynamical model based on Reynolds averaged Navier-Stokes equations. The results are contrasted with the standard analysis based on shallow water Saint-Venant equations. We first show that the stability of both transverse modes (ripples) and of small wavelength inclined modes (bars) predicted by the Saint-Venant approach are artefacts of this hydrodynamical approximation. When using a more reliable hydrodynamical model, the dispersion relation does not present any maximum of the growth rate when the sediment transport is assumed to be locally saturated. The analysis therefore reveals the fundamental importance of the relaxation of sediment transport towards equilibrium as it it is responsible for the stabilisation of small wavelength modes. This dynamical mechanism is characterised by the saturation number, defined as the ratio of the saturation length to the water depth Lsat/H. This dimensionless number controls the transition from ripples (transverse patte...

  8. The booming dune instability

    Science.gov (United States)

    Andreotti, B.; Bonneau, L.

    2009-12-01

    Sand avalanches flowing down the leeward face of some desert dunes spontaneously produce a loud sound with a characteristic vibrato around a well defined frequency, a phenomenon called the "song of dunes". Here, we show theoretically that an homogenous granular surface flow is linearly unstable towards growing elastic waves when a localized shear band form at the interface between the avalanche and the static part of the dune. We unravel the nature of the acoustic amplifying mechanism at the origin of this booming instability. The dispersion relation and the shape of the most unstable modes are computed and compared to field records performed in the Atlantic Sahara. We finally show that several characteristics predicted by the model and observed in the field allow to dismiss former hypothesis based on resonances or the synchronisation of sand grain collisions.

  9. Combustion Instabilities Modeled

    Science.gov (United States)

    Paxson, Daniel E.

    1999-01-01

    NASA Lewis Research Center's Advanced Controls and Dynamics Technology Branch is investigating active control strategies to mitigate or eliminate the combustion instabilities prevalent in lean-burning, low-emission combustors. These instabilities result from coupling between the heat-release mechanisms of the burning process and the acoustic flow field of the combustor. Control design and implementation require a simulation capability that is both fast and accurate. It must capture the essential physics of the system, yet be as simple as possible. A quasi-one-dimensional, computational fluid dynamics (CFD) based simulation has been developed which may meet these requirements. The Euler equations of mass, momentum, and energy have been used, along with a single reactive species transport equation to simulate coupled thermoacoustic oscillations. A very simple numerical integration scheme was chosen to reduce computing time. Robust boundary condition procedures were incorporated to simulate various flow conditions (e.g., valves, open ends, and choked inflow) as well as to accommodate flow reversals that may arise during large flow-field oscillations. The accompanying figure shows a sample simulation result. A combustor with an open inlet, a choked outlet, and a large constriction approximately two thirds of the way down the length is shown. The middle plot shows normalized, time-averaged distributions of the relevant flow quantities, and the bottom plot illustrates the acoustic mode shape of the resulting thermoacoustic oscillation. For this simulation, the limit cycle peak-to-peak pressure fluctuations were 13 percent of the mean. The simulation used 100 numerical cells. The total normalized simulation time was 50 units (approximately 15 oscillations), which took 26 sec on a Sun Ultra2.

  10. Internal rotor friction instability

    Science.gov (United States)

    Walton, J.; Artiles, A.; Lund, J.; Dill, J.; Zorzi, E.

    1990-01-01

    The analytical developments and experimental investigations performed in assessing the effect of internal friction on rotor systems dynamic performance are documented. Analytical component models for axial splines, Curvic splines, and interference fit joints commonly found in modern high speed turbomachinery were developed. Rotor systems operating above a bending critical speed were shown to exhibit unstable subsynchronous vibrations at the first natural frequency. The effect of speed, bearing stiffness, joint stiffness, external damping, torque, and coefficient of friction, was evaluated. Testing included material coefficient of friction evaluations, component joint quantity and form of damping determinations, and rotordynamic stability assessments. Under conditions similar to those in the SSME turbopumps, material interfaces experienced a coefficient of friction of approx. 0.2 for lubricated and 0.8 for unlubricated conditions. The damping observed in the component joints displayed nearly linear behavior with increasing amplitude. Thus, the measured damping, as a function of amplitude, is not represented by either linear or Coulomb friction damper models. Rotordynamic testing of an axial spline joint under 5000 in.-lb of static torque, demonstrated the presence of an extremely severe instability when the rotor was operated above its first flexible natural frequency. The presence of this instability was predicted by nonlinear rotordynamic time-transient analysis using the nonlinear component model developed under this program. Corresponding rotordynamic testing of a shaft with an interference fit joint demonstrated the presence of subsynchronous vibrations at the first natural frequency. While subsynchronous vibrations were observed, they were bounded and significantly lower in amplitude than the synchronous vibrations.

  11. Equilibrium Electro-osmotic Instability

    CERN Document Server

    Rubinstein, Isaak

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. First theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge-selectivity for the sake of simplicity and so did the subsequent numerical studies of various time-dependent and nonlinear features of electro-osmotic instability. In this letter, we show that relaxing the assumption of perfect charge-selectivity (tantamount to fixing the electrochemical potential in the solid) allows for equilibrium electro-osmotic instability. Moreover, we s...

  12. Instability in Shocked Granular Gases

    CERN Document Server

    Sirmas, Nick; Radulescu, Matei

    2013-01-01

    Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by performing discrete-particle simulations of inelastic media undergoing shock compression. By allowing finite dissipation within the shock wave, instability manifests itself as distinctive high density non-uniformities and convective rolls within the shock structure. In the present study we have extended this work to investigate this instability at the continuum level. We modeled the Euler equations for granular gases with a modified cooling rate to include an impact velocity threshold necessary for inelastic collisions. Our results showed a fair agreement between the continuum and discrete-particle models. Discrepancies, such as higher frequency instabilities in our continuum results may be attributed to the absence of higher order effects.

  13. Instability in shocked granular gases

    International Nuclear Information System (INIS)

    Shocks in granular media, such as vertically oscillated beds, have been shown to develop instabilities. Similar jet formation has been observed in explosively dispersed granular media. Our previous work addressed this instability by performing discrete-particle simulations of inelastic media undergoing shock compression. By allowing finite dissipation within the shock wave, instability manifests itself as distinctive high density non-uniformities and convective rolls within the shock structure. In the present study we have extended this work to investigate this instability at the continuum level. We modeled the Euler equations for granular gases with a modified cooling rate to include an impact velocity threshold necessary for inelastic collisions. Our results showed a fair agreement between the continuum and discrete-particle models. Discrepancies, such as higher frequency instabilities in our continuum results may be attributed to the absence of higher order effects.

  14. Gravitational Instabilities in Circumstellar Disks

    CERN Document Server

    Kratter, Kaitlin M

    2016-01-01

    [Abridged] Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability, and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability, supplemented with a survey of numerical simulations that aim to capture the non-linear evolution. We emphasize the role of thermodynamics and large scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analyt...

  15. Kinetic shear Alfvén instability in the presence of impurity ions in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Gaimin; Shen, Y.; Xie, T.; He, Zhixiong; He, Hongda [Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China); Qi, Longyu [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Cui, Shaoyan [School of Mathematics and Information, Ludong University, Yantai 264025 (China)

    2013-10-15

    The effects of impurity ions on the kinetic shear Alfvén (KSA) instability in tokamak plasmas are investigated by numerically solving the integral equations for the KSA eigenmode in the toroidal geometry. The kinetic effects of hydrogen and impurity ions, including transit motion, finite ion Larmor radius, and finite-orbit-width, are taken into account. Toroidicity induced linear mode coupling is included through the ballooning-mode representation. Here, the effects of carbon, oxygen, and tungsten ions on the KSA instability in toroidal plasmas are investigated. It is found that, depending on the concentration and density profile of the impurity ions, the latter can be either stabilizing or destabilizing for the KSA modes. The results here confirm the importance of impurity ions in tokamak experiments and should be useful for analyzing experimental data as well as for understanding anomalous transport and control of tokamak plasmas.

  16. Gravitational Instabilities in Circumstellar Disks

    Science.gov (United States)

    Kratter, Kaitlin; Lodato, Giuseppe

    2016-09-01

    Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

  17. Instabilities of advection-dominated accretion flows

    CERN Document Server

    Chen, X

    1996-01-01

    Accretion disk instabilities are briefly reviewed. Some details are given to the short-wavelength thermal instabilities and the convective instabilities. Time-dependent calculations of two-dimensional advection-dominated accretion flows are presented.

  18. Designing the Balloon Experimental Twin Telescope for Infrared Interferometry

    Science.gov (United States)

    Rinehart, Stephen

    2011-01-01

    While infrared astronomy has revolutionized our understanding of galaxies, stars, and planets, further progress on major questions is stymied by the inescapable fact that the spatial resolution of single-aperture telescopes degrades at long wavelengths. The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter boom interferometer to operate in the FIR (30-90 micron) on a high altitude balloon. The long baseline will provide unprecedented angular resolution (approx. 5") in this band. In order for BETTII to be successful, the gondola must be designed carefully to provide a high level of stability with optics designed to send a collimated beam into the cryogenic instrument. We present results from the first 5 months of design effort for BETTII. Over this short period of time, we have made significant progress and are on track to complete the design of BETTII during this year.

  19. Stabilization of ballooning modes with sheared toroidal rotation

    International Nuclear Information System (INIS)

    A new code demonstrates the stabilization of MHD ballooning modes by sheared toroidal rotation. A shifted-circle 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, ωA = VA/qR. Shear stabilization is also demonstrated for an equilibrium reconstruction of a DIII-D VH-mode. (author). 9 refs, 3 figs

  20. 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.

  1. [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. PMID:24483961

  2. Electrodynamics of the stratosphere using 5000 cu m superpressure balloons

    Science.gov (United States)

    Holzworth, R. H.

    1983-01-01

    The Electrodynamics of the Middle Atmosphere research project encompasses the design of a microprocessor-controlled payload and the launch of up to eight small superpressure balloons in the 1982-1984 period. The primary payload instrument will measure the vector electric field from dc to 10 kHz, and the payloads will include instruments measuring local ionization, electrical conductivity, magnetic field, and temperature and pressure fluctuations. In addition, optical lightning will be recorded. The simultaneous measurement of these stratospheric parameters by several balloons, for periods extending over several solar rotations, will allow the study of electrical coupling between atmosphere and magnetosphere, of global current systems, and of global response to solar flares and magnetospheric storms.

  3. 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.

  4. Intraaortic Balloon Pump Counterpulsation and Cerebral Autoregulation: an observational study

    OpenAIRE

    Boots Rob; Barnett Adrian G; Timms Daniel; Dunster Kimble; Geng Shureng; Bellapart Judith; Fraser John F

    2010-01-01

    Abstract Background The use of Intra-aortic counterpulsation is a well established supportive therapy for patients in cardiac failure or after cardiac surgery. Blood pressure variations induced by counterpulsation are transmitted to the cerebral arteries, challenging cerebral autoregulatory mechanisms in order to maintain a stable cerebral blood flow. This study aims to assess the effects on cerebral autoregulation and variability of cerebral blood flow due to intra-aortic balloon pump and in...

  5. Double-balloon enteroscopy in detecting small intestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    ZHI Fa-chao; PAN De-shou; ZHOU Dian-yuan; XIAO Bing; JIANG Bo; WAN Tian-mo; GUO Yu; ZHOU Dan; WANG Li-hui; CHEN Jin-feng; XIE Lu

    2005-01-01

    @@ Digestive tract hemorrhage is a common disease of the digestive system, but about 0.4%-5% intestinal bleeding can not be detected with gastroscope or colonscope.1 Since the intestine is long, tortuous, far away from both ends of the digestive tract and unfixed in position, clinical diagnosis of the bleeding is relatively difficult. Yamamoto and Sugano2 reported the clinical application of double-balloon enteroscope at American DDW in 2003.

  6. Effect of Externally Driven Magnetic Islands on Resistive Ballooning Turbulence

    OpenAIRE

    NISHIMURA, Seiya; Yagi, Masatoshi

    2011-01-01

    Turbulent transport in the edge region of tokamak plasmas is simulated using a reduced set of magnetohydrodynamic equations. Repetitive and intermittent transport bursts driven by resistive ballooning turbulence with external heating are observed. The effect of a resonant magnetic perturbation (RMP) on turbulent heat transport is examined, where the electromagnetic response of the plasma to the RMP is solved consistently. The penetration of the RMP excites a magnetic island chain and damps th...

  7. Balloon Kyphoplasty: An Effective Treatment for Kummell Disease?

    Science.gov (United States)

    Kim, Pius

    2016-01-01

    Objective The purpose of this study was to evaluate the efficacy of balloon kyphoplasty for treating Kummel disease accompanying severe osteoporosis. Methods Twelve patients with single-level Kummell disease accompanied by severe osteoporosis were enrolled in this investigation. After postural reduction for 1 or 2 days, balloon kyphoplasty was performed on the collapsed vertebrae. Clinical results, radiological parameters, and related complications were assessed at 7 days, 1 month and 6 months after the procedure. Results Prior to kyphoplasty, the mean pain score (according to the visual analogue scale) was 8.0. Seven days after the procedure, this score improved to 2.5. Despite the significant improvement compared to preoperative value, the score increased to 4.0 at 6 months after the procedure. The mean preoperative vertebral height loss was 55.4%. Kyphoplasty reduced this loss to 31.6%, but it increased to 38.7% at 6 months after the procedure. The kyphotic angle improved significantly from 22.4°±4.9° (before the procedure) to 10.1°±3.8° after surgery, However, the improved angle was not maintained 6 months after the procedure. The mean correction loss for the kyphotic deformity was 7.2° at 6 months after the procedure. Three out of 12 patients sustained adjacent fractures after balloon kyphoplasty within 6 months. Conclusion Although balloon kyphoplasty for treating Kummell disease is known to provide stabilization and pain relief, it may be associated with the development of adjacent fractures and aggravated kyphosis. PMID:27799987

  8. Latex Micro-balloon Pumping in Centrifugal Microfluidic Platforms

    OpenAIRE

    Aeinehvand, Mohammad Mahdi; Ibrahim, Fatimah; Al-Faqheri, Wisam; Thio, Tzer Hwai Gilbert; Kazemzadeh, Amin; Wadi harun, Sulaiman; Madou, Marc

    2014-01-01

    Centrifugal microfluidic platforms have emerged as point-of-care diagnostic tools. However, the unidirectional nature of the centrifugal force limits the available space for multi-stepped processes on a single microfluidics disc. To overcome this limitation, a passive pneumatic pumping method actuated at high rotational speeds has been previously proposed to pump liquid against the centrifugal force. In this paper, a novel micro-balloon pumping method that relies on elastic energy stored in a...

  9. 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.

  10. 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.

  11. The balloon-borne electron telescope with scintillating fibers (BETS)

    CERN Document Server

    Torii, S; Tateyama, N; Yoshida, K; Ouchi, Y; Yamagami, T; Saitô, Y; Murakami, H; Kobayashi, T; Komori, Y; Kasahara, K; Yuda, T; Nishimura, J

    2000-01-01

    we describe a new detector system developed for high-altitude balloon flights to observe the cosmic-ray electrons above 10 GeV. The balloon borne electron telescope with Scintillating (BETS) fibers instrument is an imaging calorimeter which is capable of selecting electrons against the large background of protons. The calorimeter is composed of a sandwich of scintillating optical-fiber belts and lead plates with a combination of three plastic scintillators for the shower trigger. The total thickness of lead is 40 mm (~7.1 r.l.) and the number of fiber belts is nine. In each belt, alternating layers are oriented in orthogonal (x and y) directions. Two sets of an intensified CCD camera are adopted for read-out of the scintillating fibers in the x and y direction, respectively. The accelerator beam tests were carried out to study the performance of detector for electrons in 1996 and for protons in 1997 at CERN-SPS. The instrument was successfully flown aboard high-altitude balloon in 1997 and 1998. It is demonst...

  12. 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.

  13. Inverted Meckel's diverticulum preoperatively diagnosed using double-balloon enteroscopy.

    Science.gov (United States)

    Takagaki, Kosuke; Osawa, Satoshi; Ito, Tatsuhiro; Iwaizumi, Moriya; Hamaya, Yasushi; Tsukui, Hiroe; Furuta, Takahisa; Wada, Hidetoshi; Baba, Satoshi; Sugimoto, Ken

    2016-05-01

    An inverted Meckel's diverticulum is a rare gastrointestinal congenital anomaly that is difficult to diagnose prior to surgery and presents with anemia, abdominal pain, or intussusception. Here, we report the case of 57-year-old men with an inverted Meckel's diverticulum, who was preoperatively diagnosed using double-balloon enteroscopy. He had repeatedly experienced epigastric pain for 2 mo. Ultrasonography and computed tomography showed intestinal wall thickening in the pelvis. Double-balloon enteroscopy via the anal route was performed for further examination, which demonstrated an approximately 8-cm, sausage-shaped, submucosal tumor located approximately 80 cm proximal to the ileocecal valve. A small depressed erosion was observed at the tip of this lesion. Forceps biopsy revealed heterotopic gastric mucosa. Thus, the patient was diagnosed with an inverted Meckel's diverticulum, and single-incision laparoscopic surgery was performed. This case suggests that an inverted Meckel's diverticulum should be considered as a differential diagnosis for a submucosal tumor in the ileum. Balloon-assisted enteroscopy with forceps biopsy facilitate a precise diagnosis of this condition. PMID:27158212

  14. A Low Cost Weather Balloon Borne Solar Cell Calibration Payload

    Science.gov (United States)

    Snyder, David B.; Wolford, David S.

    2012-01-01

    Calibration of standard sets of solar cell sub-cells is an important step to laboratory verification of on-orbit performance of new solar cell technologies. This paper, looks at the potential capabilities of a lightweight weather balloon payload for solar cell calibration. A 1500 gr latex weather balloon can lift a 2.7 kg payload to over 100,000 ft altitude, above 99% of the atmosphere. Data taken between atmospheric pressures of about 30 to 15 mbar may be extrapolated via the Langley Plot method to 0 mbar, i.e. AMO. This extrapolation, in principle, can have better than 0.1 % error. The launch costs of such a payload arc significantly less than the much larger, higher altitude balloons, or the manned flight facility. The low cost enables a risk tolerant approach to payload development. Demonstration of 1% standard deviation flight-to-flight variation is the goal of this project. This paper describes the initial concept of solar cell calibration payload, and reports initial test flight results. .

  15. 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.

  16. Early clinical outcome and complications related to balloon kyphoplasty

    Directory of Open Access Journals (Sweden)

    Martin Bergmann

    2012-06-01

    Full Text Available The treatment of painful osteoporotic vertebral compression fractures using transpedicular cement augmentation has grown significantly over the last two decades. The benefits of balloon kyphoplasty compared to conservative treatment remain controversial and are discussed in the literature. The complication rates of vertebroplasty and kyphoplasty are considered to be low. The focus of this study was the analysis of acute and clinically relevant complications related to this procedure. In our department, all patients treated between February 2002 and February 2011 with percutaneous cement augmentation (372 patients, 522 augmented vertebral bodies were prospectively recorded. Demographic data, comorbidities, fracture types, intraoperative data and all complications were documented. The pre- and postoperative pain-level and neurological status (Frankel-Score were evaluated. All patients underwent a standardized surgical procedure. Two hundred and ninety-seven patients were treated solely by balloon kyphoplasty; 216 females (72.7% and 81 males (27.3%. Average patient age was 76.21 years (±10.71, range 35-98 years. Average American Society Anestesiologists score was 3.02. According to the Orthopedic Trauma Association classification, there were 69 A 1.1 fractures, 177 A 1.2 fractures, 178 A 3.1.1 fractures and 3 A 3.1.3 fractures. Complications were divided into preoperative, intraoperative and postoperative events. There were 4 pre-operative complications: 3 patients experienced persistent pain after the procedure. In one case, the pedicles could not be visualized during the procedure and the surgery was terminated. One hundred and twenty-nine (40.06% of the patients showed intraoperative cement leaking outside the vertebras, one severe hypotension and tachycardia as reaction to the inflation of the balloons, and there was one cardiac arrest during surgery. Postoperative subcutaneous hematomas were observed in 3 cases, 13 patients developed a

  17. Nonlinear ideal magnetohydrodynamics instabilities

    International Nuclear Information System (INIS)

    Explosive phenomena such as internal disruptions in toroidal discharges and solar flares are difficult to explain in terms of linear instabilities. A plasma approaching a linear stability limit can, however, become nonlinearly and explosively unstable, with noninfinitesimal perturbations even before the marginal state is reached. For such investigations, a nonlinear extension of the usual MHD (magnetohydrodynamic) energy principle is helpful. (This was obtained by Merkel and Schlueter, Sitzungsberichted. Bayer. Akad. Wiss., Munich, 1976, No. 7, for Cartesian coordinate systems.) A coordinate system independent Eulerian formulation for the Lagrangian allowing for equilibria with flow and with built-in conservation laws for mass, magnetic flux, and entropy is developed in this paper which is similar to Newcomb's Lagrangian method of 1962 [Nucl. Fusion, Suppl., Pt. II, 452 (1962)]. For static equilibria nonlinear stability is completely determined by the potential energy. For a potential energy which contains second- and nth order or some more general contributions only, it is shown in full generality that linearly unstable and marginally stable systems are explosively unstable even for infinitesimal perturbations; linearly absolutely stable systems require finite initial perturbations. For equilibria with Abelian symmetries symmetry breaking initial perturbations are needed, which should be observed in numerical simulations. Nonlinear stability is proved for two simple examples, m=0 perturbations of a Bennet Z-pinch and z-independent perturbations of a θ pinch. The algebra for treating these cases reduces considerably if symmetries are taken into account from the outset, as suggested by M. N. Rosenbluth (private communication, 1992)

  18. 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

  19. Intestinal cholesterol embolism resulting from intra-aortic balloon pumping: a case report

    OpenAIRE

    Yamaguchi, Satoshi; Kakazu, Masanori; Osamu, Arasaki

    2014-01-01

    Introduction Intra-aortic balloon pumping is used in elective percutaneous coronary intervention for increasing coronary blood flow. However, intra-aortic balloon pumping may decrease visceral blood flow and cause mesenteric ischemia by visceral artery obstruction. Case presentation We report the case of a 79-year-old Asian man in whom elective percutaneous coronary intervention was performed with intra-aortic balloon pumping. He died from mesenteric ischemia 25 hours after the procedure. Mic...

  20. Baryon Instability in SUSY Models

    OpenAIRE

    Nath, Pran; Arnowitt, R.

    1996-01-01

    Comment: 14 pages, latex, 1 fig, to be published in proceedings of the International Workshop on " Future Prospects of Baryon Instability Search in p-Decay and n-nbar Oscillation Experiments", Oak Ridge, Tennessee, March 28-30,1996

  1. Intrinsic Instability of Coronal Streamers

    CERN Document Server

    Chen, Y; Song, H Q; Shi, Q Q; Feng, S W; Xia, L D; 10.1088/0004-637X/691/2/1936

    2009-01-01

    Plasma blobs are observed to be weak density enhancements as radially stretched structures emerging from the cusps of quiescent coronal streamers. In this paper, it is suggested that the formation of blobs is a consequence of an intrinsic instability of coronal streamers occurring at a very localized region around the cusp. The evolutionary process of the instability, as revealed in our calculations, can be described as follows: (1) through the localized cusp region where the field is too weak to sustain the confinement, plasmas expand and stretch the closed field lines radially outward as a result of the freezing-in effect of plasma-magnetic field coupling; the expansion brings a strong velocity gradient into the slow wind regime providing the free energy necessary for the onset of a subsequent magnetohydrodynamic instability; (2) the instability manifests itself mainly as mixed streaming sausage-kink modes, the former results in pinches of elongated magnetic loops to provoke reconnections at one or many loc...

  2. High-Altitude Ballooning Program at the Indian Institute of Astrophysics

    CERN Document Server

    Nayak, A; Safonova, M; Murthy, Jayant

    2013-01-01

    We have begun a program of high altitude ballooning at the Indian Institute of Astrophysics, Bangalore. Recent advances in balloons as well as in electronics have made possible scientific payloads at costs accessible to university departments. The primary purpose of this activity is to test low-cost ultraviolet (UV) payloads for eventual space flight, but to also explore phenomena occurring in the upper atmosphere, including sprites and meteorite impacts, using balloon-borne payloads. This paper discusses the results of three tethered balloon experiments carried out at the CREST campus of IIA, Hosakote and our plans for the future. We also describe the stages of payload development for these experiments.

  3. Development of ultra-thin polyethylene balloons for high altitude research upto mesosphere

    CERN Document Server

    Kumar, B Suneel; Ojha, D K; Peter, G Stalin; Vasudevan, R; Anand, D; Kulkarni, P M; Reddy, V Anmi; Rao, T V; Sreenivasan, S

    2014-01-01

    Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group at TIFR expressed the need for balloons capable of carrying the X-ray telescopes to altitudes up to 42 km, the balloon group initiated research and development work on indigenous balloon grade films in various thickness not only for the main experiment but also in parallel, took up the development of thin films in thickness range 5 to 6 microns for fabrication of sounding balloons required for probing the stratosphere up to 42 km as the regular 2000 grams rubber balloon ascents could not reach altitudes higher than 38 km. By the year 1999, total indigenisation of sounding balloon manufacture was accomplished. The work on balloon grade ultra-thin polyethylene film in thickness range 2.8 to 3.8 microns for fabrication of balloons capable of penetrating mesosphere ...

  4. Waves and instabilities in plasmas

    International Nuclear Information System (INIS)

    The contents of this book are: Plasma as a Dielectric Medium; Nyquist Technique; Absolute and Convective Instabilities; Landau Damping and Phase Mixing; Particle Trapping and Breakdown of Linear Theory; Solution of Viasov Equation via Guilding-Center Transformation; Kinetic Theory of Magnetohydrodynamic Waves; Geometric Optics; Wave-Kinetic Equation; Cutoff and Resonance; Resonant Absorption; Mode Conversion; Gyrokinetic Equation; Drift Waves; Quasi-Linear Theory; Ponderomotive Force; Parametric Instabilities; Problem Sets for Homework, Midterm and Final Examinations

  5. Material Instabilities in Particulate Systems

    Science.gov (United States)

    Goddard, J. D.

    1999-01-01

    Following is a brief summary of a theoretical investigation of material (or constitutive) instability associated with shear induced particle migration in dense particulate suspensions or granular media. It is shown that one can obtain a fairly general linear-stability analysis, including the effects of shear-induced anisotropy in the base flow as well as Reynolds dilatancy. A criterion is presented here for simple shearing instability in the absence of inertia and dilatancy.

  6. Midcarpal instability: a radiological perspective

    Energy Technology Data Exchange (ETDEWEB)

    Toms, Andoni Paul [Norfolk and Norwich University Hospital NHS Trust, Department of Radiology, Norwich, Norfolk (United Kingdom); Radiology Academy, Cotman Centre, Norwich, Norfolk (United Kingdom); Chojnowski, Adrian [Norfolk and Norwich University Hospital NHS Trust, Department of Orthopaedic Surgery, Norwich, Norfolk (United Kingdom); Cahir, John G. [Norfolk and Norwich University Hospital NHS Trust, Department of Radiology, Norwich, Norfolk (United Kingdom)

    2011-05-15

    Midcarpal instability (MCI) is the result of complex abnormal carpal motion at the midcarpal joint of the wrist. It is a form of non-dissociative carpal instability (CIND) and can be caused by various combinations of extrinsic ligament injuries that then result in one of several subtypes of MCI. The complex patterns of injury and the kinematics are further complicated by competing theories, terminology and classifications of MCI. Palmar, dorsal, ulna midcarpal instability, and capitolunate or chronic capitolunate instability are all descriptions of types of MCI with often overlapping features. Palmar midcarpal instability (PMCI) is the most commonly reported type of MCI. It has been described as resulting from deficiencies in the ulna limb of the palmar arcuate ligament (triquetrohamate-capitate) or the dorsal radiotriquetral ligaments, or both. Unstable carpal articulations can be treated with limited carpal arthrodesis or the ligamentous defects can be treated with capsulorrhaphy or ligament reconstruction. Conventional radiographic abnormalities are usually limited to volar intercalated segment instability (VISI) patterns of carpal alignment and are not specific. For many years stress view radiographs and videofluoroscopy have been the methods of choice for demonstrating carpal instability and abnormal carpal kinematics respectively. Dynamic US can be also used to demonstrate midcarpal dyskinesia including the characteristic triquetral ''catch-up'' clunk. Tears of the extrinsic ligaments can be demonstrated with MR arthrography, and probably with CT arthrography, but intact yet redundant ligaments are more difficult to identify. The exact role of these investigations in the diagnosis, categorisation and management of midcarpal instability has yet to be determined. (orig.)

  7. Instability of enclosed horizons

    Science.gov (United States)

    Kay, Bernard S.

    2015-03-01

    We point out that there are solutions to the scalar wave equation on dimensional Minkowski space with finite energy tails which, if they reflect off a uniformly accelerated mirror due to (say) Dirichlet boundary conditions on it, develop an infinite stress-energy tensor on the mirror's Rindler horizon. We also show that, in the presence of an image mirror in the opposite Rindler wedge, suitable compactly supported arbitrarily small initial data on a suitable initial surface will develop an arbitrarily large stress-energy scalar near where the two horizons cross. Also, while there is a regular Hartle-Hawking-Israel-like state for the quantum theory between these two mirrors, there are coherent states built on it for which there are similar singularities in the expectation value of the renormalized stress-energy tensor. We conjecture that in other situations with analogous enclosed horizons such as a (maximally extended) Schwarzschild black hole in equilibrium in a (stationary spherical) box or the (maximally extended) Schwarzschild-AdS spacetime, there will be similar stress-energy singularities and almost-singularities—leading to instability of the horizons when gravity is switched on and matter and gravity perturbations are allowed for. All this suggests it is incorrect to picture a black hole in equilibrium in a box or a Schwarzschild-AdS black hole as extending beyond the past and future horizons of a single Schwarzschild (/Schwarzschild-AdS) wedge. It would thus provide new evidence for 't Hooft's brick wall model while seeming to invalidate the picture in Maldacena's ` Eternal black holes in AdS'. It would thereby also support the validity of the author's matter-gravity entanglement hypothesis and of the paper ` Brick walls and AdS/CFT' by the author and Ortíz.

  8. Thromboembolic events associated with single balloon-, double balloon-, and stent-assisted coil embolization of asymptomatic unruptured cerebral aneurysms: evaluation with diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takigawa, Tomoji; Suzuki, Kensuke; Sugiura, Yoshiki; Suzuki, Ryotaro; Takano, Issei; Shimizu, Nobuyuki; Tanaka, Yoshihiro; Hyodo, Akio [Dokkyo Medical University Koshigaya Hospital, Department of Neurosurgery, Koshigaya, Saitama (Japan)

    2014-12-15

    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.)

  9. Influence of inflation pressure and balloon size on the development of intimal hyperplasia after balloon angioplasty. A study in the atherosclerotic rabbit.

    Science.gov (United States)

    Sarembock, I J; LaVeau, P J; Sigal, S L; Timms, I; Sussman, J; Haudenschild, C; Ezekowitz, M D

    1989-10-01

    To evaluate the effect of balloon size and inflation pressure on acute and subsequent outcome following balloon angioplasty (BA), 70 New Zealand White rabbits with bilateral femoral atherosclerosis were assigned to four groups: group 1, oversized balloon, low inflation pressure (n = 35 vessels; balloon size, 3.0 mm/inflation pressure, 5 atm); group 2, oversized balloon, high inflation pressure (n = 36; 3.0 mm/10 atm); group 3, appropriate size, low inflation pressure (n = 17; 2.5 mm/5 atm); and group 4, appropriate size balloon, high inflation pressure (n = 19; 2.5 mm/10 atm). Angiograms were obtained before, 10 minutes after, and 28 days after BA and read by two blinded observers using electronic calipers. The in vivo balloon-to-vessel ratio was measured for each group. There were eight non-BA controls. Rabbits were sacrificed either immediately (n = 34) or at 28 days after BA (n = 36), with the femoral vessels pressure perfused for histologic and morphometric analysis. The latter was performed at 28 days only. Absolute angiographic diameters increased in all groups immediately after BA (p less than 0.01). Acute angiographic success, defined as greater than 20% increase in luminal diameter, was higher using high inflation pressure (group 2, 32/36 [89%] and group 4, 16/19 [84%] vs. group 1, 23/35 [66%] and group 3, 9/17 [53%]; p less than 0.05). A 3.0-mm balloon resulted in significant oversizing irrespective of inflation pressure (balloon-to-vessel ratio, 1.5 +/- 0.1 vs. 1.1 +/- 0.1 to 1, for the 2.5-mm balloon). Vessels exposed to high inflation pressure had a significantly higher incidence of mural thrombus, dissection (p less than 0.01), and medial necrosis versus low pressure (p less than 0.05). At 28 days, the rates of restenosis (defined as greater than 50% loss of initial gain) were 14/20 (70%), 11/16 (69%), 5/10 (50%), and 5/10 (50%) for groups 1 through 4 (p = NS; a trend in favor of the groups using an oversized balloon). There was an increase in the

  10. Experimental investigation of undesired stable equilibria in pumpkin shape super-pressure balloon designs

    Science.gov (United States)

    Schur, W.

    The scientific community's desire for large capacity, constant altitude, long duration stratospheric platforms is not likely going to be met by un-reinforced spherical super-pressure balloons. More likely, the pneumatic envelope for the large-scale super-pressure balloon of the future will be a tendon reinforced structure in which the tendons perform the primary pressure load confining function and the skin serves as a gas barrier and transfers the local pressure load to the tendons. NASA's Ultra Long Duration Balloon (ULDB), which is currently under development, is of that type. By separating the load carrying function of the tendons and the skin a number of advantages are gained. Perhaps most important is the fact that the required skin strength remains to first order independent of the balloon size. Only the size and number of tendons are dictated by the balloon size. By designing the balloon to be at least quasi statically determinate, the stress distributions are more certain, and stress raisers due to fabrication imperfections are more easily controlled and it becomes unnecessary to account for load path uncertainties by providing everywhere excessive strength and structural weight. Furthermore, it becomes possible to use for the envelope skin a visco-elastic film (polyethylene) that has proven performance in the stratospheric environment. The silhouette shape of this balloon type has prompted early researchers to name this design a "pumpkin" shape balloon. Later investigators accepted this terminology. The pumpkin shape balloon concept was adopted by NASA for its ULDB design at the end of 1998 when advantages of that design over a spherical shape design were convincingly demonstrated. Two stratospheric test flights of large-scale super-pressure balloons demonstrated the functioning of this balloon type. In the second successful flight the switch was made from an excessively strong and heavy skin, a holdover from the earlier concept of a spherical design, to

  11. Long-Duration Altitude-Controlled Balloons for Venus: A Feasibility Study Informed by Balloon Flights in Remote Environments on Earth

    Science.gov (United States)

    Voss, P. B.; Nott, J.; Cutts, J. A.; Hall, J. L.; Beauchamp, P. M.; Limaye, S. S.; Baines, K. H.; Hole, L. R.

    2013-12-01

    In situ exploration of the upper atmosphere of Venus, approximately 65-77 km altitude, could answer many important questions (Limaye 2013, Crisp 2013). This region contains a time-variable UV absorber of unknown composition that controls many aspects of the heat balance on Venus. Understanding the composition and dynamics of this unknown absorber is an important science goal; in situ optical and chemical measurements are needed. However, conventional approaches do not provide access to this altitude range, repeated traverses, and a mission lifetime of several months needed to effectively carry out the science. This paper examines concepts for altitude-controlled balloons not previously flown on planetary missions that could potentially provide the desired measurements. The concepts take advantage of the fact that at 60 km altitude, for example, the atmospheric density on Venus is about 40% of the sea-level density on earth and the temperature is a moderate 230 K. The solar flux is approximately double that on earth, creating some thermal challenges, but making photovoltaic power highly effective. Using a steady-state thermodynamic model and flight data from Earth, we evaluate the suitability of two types of altitude-controlled balloons for a potential mission on Venus. Such balloons could repeatedly measure profiles, avoid diurnal temperature extremes, and navigate using wind shear. The first balloon design uses air ballast (AB) whereby ambient air can be compressed into or released from a constant-volume balloon, causing it to descend or ascend accordingly. The second design uses lift-gas compression (LGC) to change the volume of a zero-pressure balloon, thereby changing its effective density and altitude. For an altitude range of 60-75 km on Venus, we find that the superpressure volume for a LGC balloon is about 5% of that needed for an AB balloon while the maximum pressurization is the same for both systems. The compressor work per km descent of the LGC balloon

  12. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    Science.gov (United States)

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

  13. The readout electronic of EUSO-Balloon experiment

    Science.gov (United States)

    Ahmad, S.; Barrillon, P.; Blaksley, C.; Blin-Bondil, S.; Ebersoldt, A.; Dagoret-Campagne, S.; de la Taille, C.; Dulucq, F.; Gorodetzky, P.; Miyamoto, H.; Moretto, C.; Prévôt, G.; Reina, J. A. R.

    2014-03-01

    The EUSO-Balloon experiment is a pathfinder for the satellite mission JEM-EUSO whose goal will be to observe Extensive Air Showers produced in the atmosphere by the passage can detect fluorescent UV photons released by the EAS thanks to Multi-anode photomultipliers (MAPMT) arranged in 6 × 6 matrices inside Photo Detector Modules (PDM). A set of lenses is used to focus the photons on the PDM which can be compared to a UV camera taking pictures every 2.5 μs period (GTU: Gate Time Unit). The experiment consists in launching a balloon, at an altitude of 40 km, equipped with complete PDM and Data Processing systems. This project, supported by CNES and constructed by the JEM-EUSO collaboration, is meant to prove that the technology of such an instrument is possible and that the performance is satisfying, raising the Technical Readiness Level (TRL) of JEM-EUSO. Moreover, complex trigger algorithms will be assessed and the main back ground (night glow plus star light) will be studied. A complex readout electronic chain has been designed for the EUSO-Balloon project. It contains two elements: the 9 EC units and the 6 EC-ASIC boards. The EC unit includes four 64-channel Multi-Anode Photomultipliers and a set of pcbs used to supply the 14 different high voltages needed by the MAPMTs and to read out the analog anode signals. These signals are transmitted to the EC-ASIC boards which contain 6 SPACIROC ASICs each. During the year 2012, prototypes of each board were produced and tested successfully, leading to the production of the flight model PCBs in 2013.

  14. Biogenic nonmethane hydrocarbon emissions estimated from tethered balloon observations

    Science.gov (United States)

    Davis, K. J.; Lenschow, D. H.; Zimmerman, P. R.

    1994-01-01

    A new technique for estimating surface fluxes of trace gases, the mixed-layer gradient technique, is used to calculate isoprene and terpene emissions from forests. The technique is applied to tethered balloon measurements made over the Amazon forest and a pine-oak forest in Alabama at altitudes up to 300 m. The observations were made during the dry season Amazon Boundary Layer Experiment (ABLE 2A) and the Rural Oxidants in the Southern Environment 1990 experiment (ROSE I). Results from large eddy simulations of scalar transport in the clear convective boundary layer are used to infer fluxes from the balloon profiles. Profiles from the Amazon give a mean daytime emission of 3630 +/- 1400 micrograms isoprene sq m/h, where the uncertainty represents the standard deviation of the mean of eight flux estimates. Twenty profiles from Alabama give emissions of 4470 +/- 3300 micrograms isoprene sq m/h, 1740 +/- 1060 micrograms alpha-pinene sq m/h, and 790 +/- 560 micrograms beta-pinene sq m/h, respectively. These results are in agreement with emissions derived from chemical budgets. The emissions may be overestimated because of uncertainty about how to incorporate the effects of the canopy on the mixed-layer gradients. The large variability in these emission estimates is probably due to the relatively short sampling times of the balloon profiles, though spatially heterogeneous emissions may also play a role. Fluxes derived using this technique are representative of an upwind footprint of several kilometers and are independent of hydrocarbon oxidation rate and mean advection.

  15. Fine tracking system for balloon-borne telescopes

    OpenAIRE

    Ricci, M.; Pedichini, F.; Lorenzetti, D.

    2011-01-01

    We present the results of a study along with a first prototype of a high precision system (? 1 arcsec) for pointing and tracking light (near-infrared) telescopes on board stratospheric balloons. Such a system is essentially composed by a star sensor and by a star tracker, able to recognize the field and to adequately track the telescope, respectively. We present the software aimed at processing the star sensor image and the predictive algorithm that allows the fine tracking of the source at a...

  16. Balloon-borne observations of mid-latitude hydrofluoric acid

    Science.gov (United States)

    Sen, B.; Toon, G. C.; Blavier, J.-F.; Szeto, J. T.; Fleming, E. L.; Jackman, C. H.

    1995-01-01

    Measurements of stratospheric hydrofluoric acid (HF) have been made by the JPL MkIV interferometer during high-altitude balloon flights. Infrared solar absorption spectra were acquired near 35 deg N at altitudes between local tropopause and 38 km. Volume mixing ratio profiles of HF derived from 4 flights (1990-93), in conjunction with simultaneously observed N2O profiles, indicate an average rate of HF increase of (5.5 +/- 0.3)% per year, in agreement with time-dependent, two-dimensional model simulations (6% per year) and ATMOS measurements.

  17. Pointing System for the Balloon-Borne Astronomical Payloads

    CERN Document Server

    Nirmal, K; Mathew, Joice; Sarpotdar, Mayuresh; Suresh, Ambily; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-01-01

    We describe the development and implementation of a light-weight, fully autonomous 2-axis pointing and stabilization system designed for balloon-borne astronomical payloads. The system is developed using off-the-shelf components such as Arduino Uno controller, HMC 5883L magnetometer, MPU-9150 Inertial Measurement Unit (IMU) and iWave GPS receiver unit. It is a compact and rugged system which can also be used to take images/video in a moving vehicle, or in areal photography. The system performance is evaluated from the ground, as well as in conditions simulated to imitate the actual flight by using a tethered launch.

  18. The GRAD high-altitude balloon flight over Antarctica

    International Nuclear Information System (INIS)

    The Gamma Ray Advanced Detector(GRAD) consists of a n-type germanium detector inside an active bismuth-germanate Compton and charged particle shield with additional active plastic shielding across the aperture. It will be flown on a high altitude balloon at 36 km altitude at a latitude of 78 degree S over Antarctica for observations of gamma radiation emitted by the radioactive decay of 56Co in the Supernova SN1987A, for assessment of the performance of bismuth-germanate scintillation material in the radiation environment of near space, for gathering information on the gamma-ray background over Antarctica, and for testing fault-tolerant software

  19. Application of double-balloon enteroscopy in jejunal diverticular bleeding

    Institute of Scientific and Technical Information of China (English)

    Tsung-Hsing; Chen; Cheng-Tang; Chiu; Chen-Ming; Hsu

    2010-01-01

    AIM:To evaluate the efficacy of endoscopic diagnosis and therapy for jejunal diverticular bleeding.METHODS:From January 2004 to September 2009,154 patients underwent double-balloon enteroscopy (DBE) for obscure gastrointestinal bleeding.Ten consecutive patients with jejunal diverticula (5 males and 5 females) at the age of 68.7 ± 2.1 years (range 1995 years) at Chang Gung Memorial Hospital,Academic Tertiary Referral Center,were enrolled in this study.RESULTS:Of the 10 patients,5 had melena,2 had hematochezi...

  20. Detachable balloon embolization of an aneurysmal gastroduodenal arterioportal fistula

    Energy Technology Data Exchange (ETDEWEB)

    Defreyne, Luc; De Schrijver, Ignace; Vanlangenhove, Peter; Kunnen, Marc [Department of Radiology and Medical Imaging, Ghent University Hospital (Belgium)

    2002-01-01

    Extrahepatic arteriovenous fistulas involving the gastroduodenal artery and the portal venous system are rare and almost always a late complication of gastric surgery. Secondary portal hypertension and mesenteric ischemia may provoke abdominal pain, upper and lower gastrointestinal hemorrhage, diarrhea, and weight loss. Until recently, surgical excision has been the therapy of choice with excellent results. The authors report a case of gastroduodenal arterioportal fistula with a rare large interpositioned aneurysm in a cardiopulmonary-compromised patient who was considered a non-surgical candidate. The gastroduodenal arterioportal fistula was occluded endovascularly by means of a detachable balloon. A survey of the literature of this rare type of arterioportal fistula is included. (orig.)

  1. Turbulence parameter estimations from high-resolution balloon temperature measurements of the MUTSI-2000 campaign

    Directory of Open Access Journals (Sweden)

    N. M. Gavrilov

    2005-10-01

    Full Text Available Turbulence parameters in the tropo-stratosphere are analyzed using high-resolution balloon temperature measurements collected during the MUTSI (MU radar, Temperature sheets and Interferometry campaign which took place near the Middle and Upper atmosphere (MU radar (Japan, 35° N, 136° E in May 2000. Vertical profiles of the specific dissipation rate of turbulent kinetic energy, ε, and turbulent diffusivity, K, are estimated from the Thorpe lengthscale, LT. The last is obtained by using two methods. The first one consists of measuring directly LT by reordering the potential temperature profiles. The second method is based on estimates of the temperature structure constant, CT2. A relationship between LT and CT2 can be found by assuming either adiabatic vertical displacements or a model based on turbulent energy balance consideration. Analysis shows that the adiabatic assumption gives indirect estimates of LT more consistent with direct measurements. We also found that vertical profiles of analyzed turbulence characteristics show substantial intermittency, leading to substantial scatter of the local, median and average values. General trends correspond to a decrease in ε and K from the boundary layer up to altitudes 20–25 km. Layers of increased turbulence are systematically observed in the tropo-stratosphere, which may be produced by instabilities of temperature and wind profiles. These maxima may substantially increase local values of turbulence diffusivity.

    Keywords. Meteorology and atmospheric dynamics (Turbulence

  2. Fermi liquids near Pomeranchuk instabilities

    Science.gov (United States)

    Reidy, Kelly Elizabeth

    We explore features of a Fermi liquid near generalized Pomeranchuk instabilities (PIs) starting from both ordered and disordered phases. These PIs can be viewed as quantum critical points in parameter space, and thus provide an alternate viewpoint on quantum criticality. We employ the tractable crossing symmetric equation method, which is a non-perturbative diagrammatic many-particle method used to calculate the Fermi liquid interaction functions and scattering amplitudes. We consider both repulsive and attractive underlying interactions of arbitrary strength. Starting from a ferromagnetically ordered ground state, we find that upon approach to an s-wave instability in one critical channel, the system simultaneously approaches instabilities in non-critical channels. We study origins and implications of this "quantum multicriticality". We also find that a nematic (non-s-wave) instability precedes and is driven by Pomeranchuk instabilities in both the s-wave spin and density channels. Finally, we discuss potential applications of our results to physical systems, such as ferromagnetic superconductors.

  3. Radiation-induced chromosomal instability

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S. [GSI, Biophysics, Darmstadt (Germany)

    1999-03-01

    Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/{mu}m) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

  4. Balloon dilatation of post-surgical ano-rectal strictures in two infants

    Energy Technology Data Exchange (ETDEWEB)

    Wilder, W.M.; Melhem, R.E.

    1989-08-01

    Balloon dilatation of ano-rectal strictures offers an alternative to surgical repair of such lesions. This procedure has been described in higher colonic strictures secondary to necrotizing enterocolitis in infants but not in post-surgical ano-rectal strictures. Two cases of successful balloon dilatation are reported. Anal sphincter injury resulting in fecal incontinence, as previously reported, did not occur. (orig.).

  5. The balloon system with stabilized platform and oriented submillimeter telescope: Design

    Science.gov (United States)

    Lapshin, V.; Leonov, V.; Levshuk, B.; Shekshnya, V.

    1994-02-01

    A large number of scientific ballooning programs in the interests both of fundamental sciences (astrophysics, solar physics, etc.) and applied research require fine spatial orientation in inertial space of scientific instruments installed on balloons. Among these, some of the actual programs are the investigations of astophysical objects in gamma- and X-ray, far-infrared/submillimeter regions, as are also high precision magnetometric measurements, the research of the Earth's atmosphere and related ecological problems. As an applied problem, the development of modern balloon-based communication systems is pointed out. A rather large amount of different balloon platforms is developed and used in modern practice of ballooning. The Academy of Sciences of Russia (ASR) provides the design of the balloon-borne oriented and stabilized platform from 1991 (Lebedev Physical Institute, ASR). We have designed and built the balloon platform, that is considered a universal device for future balloon research, where spatial orientation is required. At the first stage of this project, the design of the far-infared version of this platform was performed. The platform is equipped with an 1-meter Cassegrain type telescope (on scheme Nesmith). The primary mirror of spherical form (f/0.5) is made from special aluminum alloy: the construction of telescope is lightweight.

  6. Single Balloon Enteroscopy for Endoscopic Retrograde Cholangiography in a Patient with Hepaticojejunostomy after Liver Transplant

    OpenAIRE

    Salvatore Gruttadauria; Riccardo Volpes; Roberto Miraglia; Marta Di Pisa; Mario Traina

    2010-01-01

    We report a case of a post-transplant patient with hepaticojejunostomy in whom we used a single balloon enteroscopy to access the biliary tree. This procedure seems to be safe and feasible for approaching the biliary anastomosis by means of the overtube and fixation of the small bowel by the balloon.

  7. The design and use of plastic balloons for stratospheric research in India

    Directory of Open Access Journals (Sweden)

    V. K. Balasubramanian

    1958-04-01

    Full Text Available "Plastic balloon flying has been developed at the Tata Institute of Fundamental Research as a research technique which has a number of important applications in India: (a cosmic ray studies; (b air sampling in the stratosphere for fall-out measurements; (c meteorological investigations; (d astronomical observations; (e defence research. Comparatively little work has been done till now in these fields at equatorial latitudes, particularly at stratospheric altitudes. Large plastic balloons with volumes of the order of half a million cubic feet, and more, have been constructed by heat welding polyethylene sheeting 0.0015"" thick. With these balloons, successful level flights at altitudes of 110,000 ft. have been achieved; in some cases, individual loads weighing a hundred pounds have been carried up. The most serious problem encountered is the extremely low temperature(about-85DegreeC, of the tropopause at the equatorial latitudes; all known plastics for balloon manufacture become brittle at these low temperatures. To overcome this, dark fabrics have been employed so that the material is heated by solar radiation. The plastic sheeting employed is extruded in India to balloon specifications from chosen polymers. The low temperatures and the turbulent conditions that prevail in the atmosphere at low latitudes present problems in balloon flying which are different from those encountered at high latitudes present in balloon flying which are different from those encountered at high latitudes. The techniques employed, the design of the balloons, and their performance under these conditions are discussed."

  8. Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty

    DEFF Research Database (Denmark)

    Heerwagen, Søren Thorup; Lönn, Lars; Schroeder, Torben V;

    2010-01-01

    Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose...... of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis....

  9. Clinical study of percutaneous transhepatic balloon dilation: a novel procedure for common bileduct stone

    Institute of Scientific and Technical Information of China (English)

    李玉亮

    2014-01-01

    Objective To investigate the safety and efficacy of percutaneous transhepatic balloon dilation for the removal of common bile duct stone.Methods Sixty-eight cases with common bile duct stone treated with percutaneous transhepatic balloon dilation in our department from July2008 to April 20l1 were analyzed retrospectively.Record CA19-9,total bilirubin,

  10. Effect of oxygen deficiency on response of CR-39 on board scientific balloons

    CERN Document Server

    Fujii, M; Osawa, A; Saitô, T; Yamamoto, K; Hasebe, T; Nakamura, T; Sasaki, H; Yanagita, T; Aglietta, M; Vernetto, S; Castellina, A; Fulgione, W; Saavedra, O; Trinchero, G C

    1999-01-01

    We should be careful about the effect of oxygen deficiency on polymeric track detectors even at balloon altitude. Results of balloon experiments and calibration experiments in a vacuum chamber at different pressures show that the effect of oxygen deficiency becomes serious at a pressure below 10 hPa.

  11. Malignant lymphoma in the ileum diagnosed by double-balloon enteroscopy

    Institute of Scientific and Technical Information of China (English)

    Kazuko Beppu; Nobuhiro Sato; Toshiki Kamano; Yasuo Hayashida; Sumio Watanabe; Taro Osada; Akihito Nagahara; Naoto Sakamoto; Tomoyoshi Shibuya; Masato Kawabe; Takeshi Terai; Toshifumi Ohkusa; Tatsuo Ogihara

    2007-01-01

    A 73-year old man presented with abdominal pain. A tumor with central ulceration was observed in the ileum using double-balloon enteroscopy. Histological findings of the biopsy specimens were consistent with malignant lymphoma. Double-balloon enteroscopy confirmed the diagnosis of a malignant lymphoma tumor which was surgically resected. The patient is still in complete remission now.

  12. Adjustable Intragastric Balloons: A 12-Month Pilot Trial in Endoscopic Weight Loss Management

    NARCIS (Netherlands)

    E. Machytka; P. Klvana; A. Kornbluth; S. Peikin; L.E.M. Mathus-Vliegen; C. Gostout; G. Lopez-Nava; S. Shikora; J. Brooks

    2011-01-01

    Intragastric balloons are associated with (1) early period intolerance, (2) diminished effect within 3-4 months, and (3) bowel obstruction risk mandating removal at 6 months. The introduction of an adjustable balloon could improve comfort and offer greater efficacy. A migration prevention function,

  13. Local drug-delivery balloon for proliferative occlusive in-stent restenosis after drug-eluting stent

    Institute of Scientific and Technical Information of China (English)

    Gianluca Rigatelli; Paolo Cardaioli; Fabio Dell'Avvocata; Massimo Giordan

    2011-01-01

    Drug-coated balloon has been developed as an alternative to drug-eluting stents for in-stent restenosis but the performance of drug infusion balloon in such setting has not been previously described. We present a case of particularly aggressive in-stent restenosis after drug eluting stent implantation treated with a new kind of drug infusion balloon developed in order to overcome the impossibility to inflate regular drug-coated balloon for several dilatation.

  14. An analysis of the deployment of a pumpkin balloon on mars

    Science.gov (United States)

    Rand, J.; Phillips, M.

    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, which produces stress resultants determined by the volume of the system, 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. The application of this technology to very large systems is currently being demonstrated by NASA's Ultra Long Duration Balloon (ULDB) Program. However, this type of balloon has certain features that may be exploited to produce a system far more robust than a comparable sphere during deployment, inflation, and operation for long periods of time. When this concept is applied to a system designed to carry two kilograms in the atmosphere of Mars, the resulting balloon is small enough to alter the construction techniques and produce an envelope which is free of tucks and folds which may cause uncontrolled stress concentrations. A technique has been demonstrated where high strength tendons may be pretensioned prior to installation along the centerline of each gore. Since this position is the shortest distance between the apex and nadir of the balloon, the tendons will automatically resist the forces caused by deployment and inflation and thereby protect the thin film gas barrier from damage. A suitable balloon has been designed for this type of mission using five-micron Mylar Type C film for the gas barrier and P O braided cables for the meridionalB load carrying members. 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 ten-kilogram system suspended at the nadir of the balloon. As the

  15. The Balloon Experimental Twin Telescope for Infrared Interferometry

    Science.gov (United States)

    Silverburg, Robert

    2009-01-01

    Astronomical studies at infrared wavelengths have dramatically improved our understanding of the universe, and observations with Spitzer, the upcoming Herschel mission, and SOFIA will continue to provide exciting new discoveries. The comparatively low spatial resolution of these missions, however, is insufficient to resolve the physical scales on which mid- to far-infrared emission arises, resulting in source and structure ambiguities that limit our ability to answer key science questions. Interferometry enables high angular resolution at these wavelengths. We have proposed a new high altitude balloon experiment, the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). High altitude operation makes far-infrared (30- 300micron) observations possible, and BETTII's 8-meter baseline provides unprecedented angular resolution (approx. 0.5 arcsec) in this band. BETTII will use a double-Fourier instrument to simultaneously obtain both spatial and spectral information. The spatially resolved spectroscopy provided by BETTII will address key questions about the nature of disks in young cluster stars and active galactic nuclei and the envelopes of evolved stars. BETTII will also lay the groundwork for future space interferometers.

  16. Background Measurements from Balloon-Borne CZT Detectors

    CERN Document Server

    Jenkins, J A; Grindlay, J E; Bloser, P F; Stahle, C K; Parker, B; Barthelmy, S D; Jenkins, Johnathan A; Narita, Tomohiko; Grindlay, Jonathan E.; Bloser, Peter F.; Stahle, Carl; Parker, Brad; Barthelmy, Scott

    2002-01-01

    We report detector characteristics and background measurements from two prototype imaging CZT detectors flown on a scientific balloon payload in May 2001. The detectors are both platinum-contact 10mm x 10mm x 5mm CZT crystals, each with a 4 $\\times$ 4 array of pixels tiling the anode. One is made from IMARAD horizontal Bridgman CZT, the other from eV Products high-pressure Bridgman material. Both detectors were mounted side-by-side in a flip-chip configuration and read out by a 32-channel IDE VA/TA ASIC preamp/shaper. We enclosed the detectors in the same 40deg field-of-view collimator (comprisinga graded passive shield and plastic scintillator) used in our previously-reported September 2000 flight. I-V curves for the detectors are diode-like, and we find that the platinum contacts adhere significantly better to the CZT surfaces than gold to previous detectors. The detectors and instrumentation performed well in a 20-hour balloon flight on 23/24 May 2001. Although we discovered a significant instrumental back...

  17. Treatment of urethral strictures with balloon dilation: A forgotten tale

    Directory of Open Access Journals (Sweden)

    Konstantinos Stamatiou

    2015-09-01

    Full Text Available Urethral stricture is a common condition that can lead to serious complications such as urinary infections and renal insufficiency secondary to urinary retention. Treatment options include catheterization and dilation, urethroplasty and endoscopic internal urethrotomy as well. Although treatment option depends on the type, length and aetiology of stricture, the choice can be influenced to varying degrees by the simplicity of the method, the preferences of the patient the available accoutrements and the patient health condition. Both urethroplasty and endoscopic internal urethrotomy require anaesthesia and thus are not suitable for many elder and unfit for surgical treatment patients. On the other hand, dilations are easy to perform in every day clinical practice however they have been associated with iatrogenic urethral trauma. In contrast, balloon dilation under vision dilates by radial application of forces against the stricture, avoiding the potentially shearing forces associated with sequential rigid dilation. Since it reduces the possibility of an iatrogenic urethral trauma and the subsequent spongiofibrosis may lead into improved therapeutic outcomes. In this report we describe a technique for the treatment of urethral strictures with balloon dilation in elder and unfit for surgical treatment patients.

  18. Balloon sinuplasty: a new concept in the endoscopic nasal surgery

    Directory of Open Access Journals (Sweden)

    Nogueira Júnior, João Flávio

    2008-12-01

    Full Text Available Introduction: Sinus diseases affect millions of people annually. Clinical treatment is effective in most patients, but in case of failure of this therapy the functional endoscopic surgery is currently the treatment choice for surgical treatment. The objective of the functional endoscopic surgery is to increase the aeration and drainage of the involved paranasal sinuses, which allows for the adequate functioning of the nasal mucosa mucociliary clearance. However, this method still has some limitations, mainly because it removes the nasal mucosa and bone tissue, and it may lead to physiologic alterations of the nasosinusal mucosa and cicatricial fibrosis. Many of these patients could be benefited from less invasive methods, with larger nasal mucosa preservation. Since 2006, an even less invasive procedure was remarked in our specialty: the balloon dilatation of the paranasal sinus ostia. Objective: The objective of this article is to define the concept of sinuplasty, its action mechanism, and present the necessary material for the procedures performance; to describe the techniques with the equipment in a nasosinusal endoscopic surgery simulator model and review the current literature about the indications, complications, results, and follow-up of patients submitted to this procedure. Balloon sinuplasty is safe and appears to be effective in the improvement of the quality of life of patients not responsive to conventional clinical therapy. New applications and indications for this equipment should be described and researched.

  19. The Use of Zylon Fibers in ULDB Balloons

    Science.gov (United States)

    Zimmerman, M.; Seely, L.; McLaughlin, J.

    Early in the development of the ULDB balloon, Zylon (PBO) was selected as the tendon material due to its favorable stress-strain properties. It is a next generation super fiber whose strength and modulus are almost double those of the p-Aramid fibers. In addition there are two versions of the Zylon, As Spun (AS) and High Modulus (HM). Data will be presented on why the HM was chosen. Early in the development process, it was learned that this material exhibited an unusual sensitivity to degradation by ambient light. This is in addition to the expected sensitivity to UV radiation (Ultraviolet). The fiber manufacturer reported all of these properties in their literature. Due to the operating environment of the ULDB (Ultra Long Duration Balloon) it is necessary to protect the tendons from both visible and UV radiation. Methods to protect the tendons will be discussed. In addition, information on the long term exposure of the braided tendon over a thirty-six month period in a controlled manufacturing plant will be provided.

  20. Percutaneous trigeminal ganglion balloon compression : experience in 40 patients.

    Directory of Open Access Journals (Sweden)

    Natarajan M

    2000-10-01

    Full Text Available Forty patients of trigeminal neuralgia were treated with percutaneous trigeminal ganglion balloon compression. Symptoms had been present since six months to twenty years. The age ranged between 23 years and 73 years. All the patients had immediate relief from pain. Two had already undergone trigeminal cistern rhizolysis. One patient had foramen ovale stenosis. After the procedure, all the patients had mild to moderate degree of ipsilateral facial sensory loss which included buccal mucosa and anterior 2/3rd of the tongue. Facial dysaesthesia (anaesthesia dolorosa was seen in only one case, who had mild involvement lasting one week. Thirty patients had altered taste sensation, probably due to general somatic sensory loss. Five patients had herpes perioralis. In this study group, two patients had already undergone microvascular decompression. All the patients were followed for a period ranging from one to eighteen months. Balloon compression technique seems to be better than injection of alcohol, glycerol or radio frequency lesion. Recurrence of pain was noted in 3 patients after one year.

  1. Balloon UV Experiments for Astronomical and Atmospheric Observations

    CERN Document Server

    Sreejith, A G; Sarpotdar, Mayuresh; Nirmal, K; Ambily, S; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

    2016-01-01

    The ultraviolet (UV) window has been largely unexplored through balloons for astronomy. We discuss here the development of a compact near-UV spectrograph with ?ber optics input for balloon ights. It is a modi?ed Czerny-Turner system built using o?-the-shelf components. The system is portable and scalable to di?erent telescopes. The use of re ecting optics reduces the transmission loss in the UV. It employs an image-intensi?ed CMOS sensor, operating in photon counting mode, as the detector of choice. A lightweight pointing system developed for stable pointing to observe astronomical sources is also discussed, together with the methods to improve its accuracy, e.g. using the in-house build star sensor and others. Our primary scienti?c objectives include the observation of bright Solar System objects such as visible to eye comets, Moon and planets. Studies of planets can give us valuable information about the planetary aurorae, helping to model and compare atmospheres of other planets and the Earth. The other ma...

  2. Balloon-borne CALET prototype payload (bCALET)

    Science.gov (United States)

    Ueyama, Yoshitaka; Torii, Shoji; Kasahara, Katsuaki; Murakami, Hiroyuki; Ozawa, Shunsuke; Akaike, Yosui; Nakai, Mikio; Aiba, Toshihide; Kai, Yuuichirou; Tamura, Tadahisa; Yoshida, Kenji; Katayose, Yusaku; Saito, Yoshitaka; Fuke, Hideyuki; Kawada, Jiro; Mizuta, Eiichi; Marrocchesi, Pier Simone; Kim, Meyoung; Bigongiari, Gabriele

    The CALorimetric Electron Telescope (CALET) payload will be installed in the Japanese Experiment Module Exposed Facility (JEM-EF) of the International Space Station (ISS). We have been developing a balloon borne payload to evaluate the performance of CALET by carring out precursor flights for the electron observation in 1-1000 GeV. The first flight of bCALET was done in 2006, and the enhanced version, bCALET-2, was successfully flown in 2009. In this paper, we describe the bCALET-3 payload which is composed of Imaging Calorimeter (IMC), Total Absorption Calorimeter (TASC) and Silicon pixel Array (SIA). IMC has an area of 320mm × 320mm, and is consisted 8 x-y layers of scintillating fiber belts inserted below tungsten plates for a fine imaging of shower particles. TASC is constructed by 6 layers of BGO scintillator blocks with an area of 300mm × 300mm, for measuring the total energy deposit of incoming shower particles. SIA owns to measure the charge number of incoming particle. Each component has very similar function with CALET with about half the area of CALET. We are planning to carry out the balloon experiment by bCALET-3 in November, 2010 for the test of the CALET capability of observing the electrons.

  3. Polar Balloon Experiment for Astrophysics Research (Polar BEAR)

    Science.gov (United States)

    Bashindzhagyan, G.; Adams, James H., Jr.; Bashindzhagyan, P.; Chilingarian, A.; Donnelly, J.; Drury, L.; Egorov, N.; Golubkov, S.; Grebenyuk, V.; Kalinin, A.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    A new balloon experiment is proposed for a long duration flight around the North Pole. The primary objective of the experiment is to measure the elemental energy spectra of high-energy cosmic rays in the region up to 10(exp 15) eV. The proposed instrument involves the combination of a large collecting area (approximately 1 x 1 square m) KLEM (Kinematic Lightweight Energy Meter) device with an ionization calorimeter having a smaller collecting area (approximately 0.5 x 0.5 square m) and integrated beneath the KLEM apparatus. This combination has several important advantages. Due to the large aperture (greater than 2 square m sr) of the KLEM device a large exposure factor can be achieved with a long duration balloon flight (2-4 weeks). The calorimeter will collect about 10% of the events already registered by KLEM and provide effective cross-calibration for both energy measurement methods. Details of the experiment and its astrophysical significance will be presented.

  4. Electrodynamics of the Middle Atmosphere: Superpressure Balloon Program

    Science.gov (United States)

    Holzworth, Robert H.

    1990-01-01

    This project called Electrodynamics of the Middle Atmosphere (EMA): Superpressure Balloon Program was begun by the PI at the Aerospace Corporation in Los Angeles under joint NSF and NASA funding originally combined in one grant ATM80-17071 and has continued at the University of Washington under grants ATM8212283, ATM84-11326 and ATM86-15628 and NASA grants NAGW-724 and NAGS-635. In the EMA experiment a comprehensive set of electrical parameters was measured during eight long-duration balloon flights in the Southern Hemisphere stratosphere. These flights resulted in the largest vector electric field data set ever collected from the stratosphere which has been a treasure-trove of new phenomena. Since the stratosphere has never been electrodynamically sampled in this systematic manner before, it is perhaps not surprising that several new discoveries have been made and reported. Another way to measure the success of this first EMA project is to note that all together the total data rate was about 1 bit/sec/payload amounting to 12 MBytes (1/3 of 1 standard 1600 BPI magnetic tape) which nevertheless has resulted in 14 papers and 2 masters theses (so far! . Ten of these papers and one masters thesis specifically acknowledge the support by NASA grant NAGS-635 are discussed herein.

  5. Longitudinal instability in HIF beams

    International Nuclear Information System (INIS)

    In contrast to an electron induction accelerator, in which the particle velocity is virtually constant, the resistive and inductive components of accelerating module impedances can cause instability for an intense non-relativistic heavy ion beam accelerated in a similar structure. Since focusing requirements at the fusion pellet imply a momentum spread approx-lt 3 x 10-4 at the end of the accelerator, it is essential to understand and suppress this instability. There is also an economic issue involved for this application; selection of parameters to control the instability must not unduly affect the efficiency and cost of the accelerator. This paper will present the results of analytic and computational work on module impedances, growth rates and feed back (forward) systems. 2 refs., 3 figs

  6. Interfacial instabilities and Kapitsa pendula

    Science.gov (United States)

    Krieger, Madison

    2015-11-01

    Determining the critera for onset and amplitude growth of instabilities is one of the central problems of fluid mechanics. We develop a parallel between the Kapitsa effect, in which a pendulum subject to high-frequency low-amplitude vibrations becomes stable in the inverted position, and interfaces separating fluids of different density. It has long been known that such interfaces can be stabilized by vibrations, even when the denser fluid is on top. We demonstrate that the stability diagram for these fluid interfaces is identical to the stability diagram for an appopriate Kapitsa pendulum. We expand the robust, ``dictionary''-type relationship between Kapitsa pendula and interfacial instabilities by considering the classical Rayleigh-Taylor, Kelvin-Helmholtz and Plateau instabilities, as well as less-canonical examples ranging in scale from the micron to the width of a galaxy.

  7. Interfacial Instability during Granular Erosion

    Science.gov (United States)

    Lefebvre, Gautier; Merceron, Aymeric; Jop, Pierre

    2016-02-01

    The complex interplay between the topography and the erosion and deposition phenomena is a key feature to model granular flows such as landslides. Here, we investigated the instability that develops during the erosion of a wet granular pile by a dry dense granular flow. The morphology and the propagation of the generated steps are analyzed in relation to the specific erosion mechanism. The selected flowing angle of the confined flow on a dry heap appears to play an important role both in the final state of the experiment, and for the shape of the structures. We show that the development of the instability is governed by the inertia of the flow through the Froude number. We model this instability and predict growth rates that are in agreement with the experiment results.

  8. Performance through Deformation and Instability

    Science.gov (United States)

    Bertoldi, Katia

    2015-03-01

    Materials capable of undergoing large deformations like elastomers and gels are ubiquitous in daily life and nature. An exciting field of engineering is emerging that uses these compliant materials to design active devices, such as actuators, adaptive optical systems and self-regulating fluidics. Compliant structures may significantly change their architecture in response to diverse stimuli. When excessive deformation is applied, they may eventually become unstable. Traditionally, mechanical instabilities have been viewed as an inconvenience, with research focusing on how to avoid them. Here, I will demonstrate that these instabilities can be exploited to design materials with novel, switchable functionalities. The abrupt changes introduced into the architecture of soft materials by instabilities will be used to change their shape in a sudden, but controlled manner. Possible and exciting applications include materials with unusual properties such negative Poisson's ratio, phononic crystals with tunable low-frequency acoustic band gaps and reversible encapsulation systems.

  9. Hydrodynamick instabilities on ICF capsules

    International Nuclear Information System (INIS)

    This article summarizes our current understanding of hydrodynamic instabilities as relevant to ICF. First we discuss classical, single mode Rayleigh-Taylor instability, and nonlinear effects in the evolution of a single mode. Then we discuss multimode systems, considering: (1) the onset of nonlinearity; (2) a second order mode coupling theory for weakly nonlinear effects, and (3) the fully nonlinear regime. Two stabilization mechanisms relevant to ICF are described next: gradient scale length and convective stabilization. Then we describe a model which is meant to estimate the weakly nonlinear evolution of multi-mode systems as relevant to ICF, given the short-wavelength stabilization. Finally, we discuss the relevant code simulation capability, and experiments. At this time we are quite optimistic about our ability to estimate instability growth on ICF capsules, but further experiments and simulations are needed to verify the modeling. 52 refs

  10. A case of asymptomatic fungal and bacterial colonization of an intragastric balloon

    Institute of Scientific and Technical Information of China (English)

    Halil Coskun; Suleyman Bozkurt

    2009-01-01

    Intragastric balloon therapy, as a part of a multidisciplinary weight management program, is an effective short-term intervention for weight loss. Although the insertion procedure is easy and generally well tolerated by patients, a few complications can occur. We report here a heavy smoker with intragastric balloon insertion complicated by colonization with opportunistic organisms. The 27-year-old female, body mass index 35.5 kg/m2, had a BioEnterics. Intragastric Balloon inserted under conscious sedation without any perioperative complications. Six months later, when the standard removal time arrived, the balloon was seen to be covered with a necrotic white-gray material. Microbiological examination revealed Enterobacter cloacae and Candida species yeast colonies. We recommend that asymptomatic fungal and/or bacterial colonization should be considered among the complications of the intragastric balloon procedure, despite its rarity.

  11. Vascular Rupture Caused by a Molding Balloon during Endovascular Aneurysm Repair: Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Young; Do, Young Soo; Park, Hong Suk; Park, Kwang Bo [Dept. of Radiology, Samsugn Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Young Wook; Kim, Dong Ik [Dept. of Surgery, Samsugn Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    Endovascular aneurysm repair (EVAR) has been accepted as an alternative to traditional open surgery in selected patients. Despite the minimally invasiveness of this treatment, several complications may occur during or after EVAR. Complications include endoleak, aortic dissection, distal embolism, or iatrogenic injury to the access artery. However, there are few reports on the vascular rupture caused by a molding balloon during EVAR. We report two cases of infrarenal abdominal aortic aneurysms complicated by procedure-related aortic or iliac artery rupture by the molding balloon during EVAR. In our cases, we observed suddenly abrupt increase of the diameter of the endograft during balloon inflation, because we inflated the balloon rapidly. In conclusion, careful attention must be paid during inflation of the molding balloon to prevent vascular rupture.

  12. Treatment of benign ureteral stricture by double J stents using high-pressure balloon angioplasty

    Institute of Scientific and Technical Information of China (English)

    YU Hua-liang; YE Lin-yang; LIN Mao-hu; YANG Yu; MIAO Rui; HU Xiao-juan

    2011-01-01

    Background Balloon dilatation angioplasty is a minimally invasive surgery for treating benign ureteral stricture. The aim of this study was to investigate the effect of placing double J (D-J) stents using high-pressure balloon angioplasty in treating benign ureteral stricture.Methods A total of 42 patients (48 cases) with benign ureteral stricture (42 had benign ureteral stricture) were investigated by inserting dual D-J stents using high-pressure balloon angioplasty. The control group contained 50 patients (57 cases) employing the conventional balloon angioplasty with a single D-J stent inserted for comparison.Results The overall effective rate of the treated and control groups was 87.8% (36/41) and 62.7% (32/51), respectively (P <0.05).Conclusion This new approach produces a better curative effect than the conventional balloon angioplasty with a single D-J stent insertion in treating benign ureteral stricture.

  13. Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms

    Science.gov (United States)

    Mahaffy, P. R.; Atreya, S. A.; Fairbrother, D. A.; Farrell, W. M.; Gorevan, S.; Jones, J.; Mitrofanov, I.; Scott, J.

    2003-01-01

    Montgolfiere balloons can provide a unique near-surface platform for an extended traverse over the polar regions of Mars. During the polar summer, such solar powered balloons would remain in the constant sun of the polar summer and could remain airborne for many weeks or even months as the atmospheric circulation would drive the balloons around the polar region many times before the balloon would cross the terminator. Such a platform for scientific measurements could provide in situ sampling of the atmosphere for trace disequilibrium species that might be indicators of present geological or biological activity in this regon. It could furthermore provide high resolution imaging, deep electromagnetic (EM) sounding for subsurface stratigraphy and liquid water, and high spatial resolution neutron measurements of subsurface ice. Technologies for robust balloon deployment on entry and controlled encounters with the surface and near subsurface for sample acquisition in otherwise inaccessible regions are presently being studied and developed with support from NASA.

  14. Laboratory blast wave driven instabilities

    Science.gov (United States)

    Kuranz, Carolyn

    2008-11-01

    This presentation discusses experiments involving the evolution of hydrodynamic instabilities in the laboratory under high-energy-density (HED) conditions. These instabilities are driven by blast waves, which occur following a sudden, finite release of energy, and consist of a shock front followed by a rarefaction wave. When a blast wave crosses an interface with a decrease in density, hydrodynamic instabilities will develop. Instabilities evolving under HED conditions are relevant to astrophysics. These experiments include target materials scaled in density to the He/H layer in SN1987A. About 5 kJ of laser energy from the Omega Laser facility irradiates a 150 μm plastic layer that is followed by a low-density foam layer. A blast wave structure similar to those in supernovae is created in the plastic layer. The blast wave crosses an interface having a 2D or 3D sinusoidal structure that serves as a seed perturbation for hydrodynamic instabilities. This produces unstable growth dominated by the Rayleigh-Taylor (RT) instability in the nonlinear regime. We have detected the interface structure under these conditions using x-ray backlighting. Recent advances in our diagnostic techniques have greatly improved the resolution of our x-ray radiographic images. Under certain conditions, the improved images show some mass extending beyond the RT spike and penetrating further than previously observed or predicted by current simulations. The observed effect is potentially of great importance as a source of mass transport to places not anticipated by current theory and simulation. I will discuss the amount of mass in these spike extensions, the associated uncertainties, and hypotheses regarding their origin We also plan to show comparisons of experiments using single mode and multimode as well as 2D and 3D initial conditions. This work is sponsored by DOE/NNSA Research Grants DE-FG52-07NA28058 (Stewardship Sciences Academic Alliances) and DE-FG52-04NA00064 (National Laser User

  15. Telomere dysfunction and chromosome instability

    Energy Technology Data Exchange (ETDEWEB)

    Murnane, John P., E-mail: jmurnane@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)

    2012-02-01

    The ends of chromosomes are composed of a short repeat sequence and associated proteins that together form a cap, called a telomere, that keeps the ends from appearing as double-strand breaks (DSBs) and prevents chromosome fusion. The loss of telomeric repeat sequences or deficiencies in telomeric proteins can result in chromosome fusion and lead to chromosome instability. The similarity between chromosome rearrangements resulting from telomere loss and those found in cancer cells implicates telomere loss as an important mechanism for the chromosome instability contributing to human cancer. Telomere loss in cancer cells can occur through gradual shortening due to insufficient telomerase, the protein that maintains telomeres. However, cancer cells often have a high rate of spontaneous telomere loss despite the expression of telomerase, which has been proposed to result from a combination of oncogene-mediated replication stress and a deficiency in DSB repair in telomeric regions. Chromosome fusion in mammalian cells primarily involves nonhomologous end joining (NHEJ), which is the major form of DSB repair. Chromosome fusion initiates chromosome instability involving breakage-fusion-bridge (B/F/B) cycles, in which dicentric chromosomes form bridges and break as the cell attempts to divide, repeating the process in subsequent cell cycles. Fusion between sister chromatids results in large inverted repeats on the end of the chromosome, which amplify further following additional B/F/B cycles. B/F/B cycles continue until the chromosome acquires a new telomere, most often by translocation of the end of another chromosome. The instability is not confined to a chromosome that loses its telomere, because the instability is transferred to the chromosome donating a translocation. Moreover, the amplified regions are unstable and form extrachromosomal DNA that can reintegrate at new locations. Knowledge concerning the factors promoting telomere loss and its consequences is

  16. Hydromagnetic Instabilities in Neutron Stars

    CERN Document Server

    Lasky, Paul D; Kokkotas, Kostas D; Glampedakis, Kostas

    2011-01-01

    We model the non-linear ideal magnetohydrodynamics of poloidal magnetic fields in neutron stars in general relativity assuming a polytropic equation of state. We identify familiar hydromagnetic modes, in particular the 'sausage/varicose' mode and 'kink' instability inherent to poloidal magnetic fields. The evolution is dominated by the kink instability, which causes a cataclysmic reconfiguration of the magnetic field. The system subsequently evolves to new, non-axisymmetric, quasi-equilibrium end-states. The existence of this branch of stable quasi-equilibria may have consequences for magnetar physics, including flare generation mechanisms and interpretations of quasi-periodic oscillations.

  17. Efficacy of Intrauterine Bakri Balloon Tamponade in Cesarean Section for Placenta Previa Patients.

    Directory of Open Access Journals (Sweden)

    Hee Young Cho

    Full Text Available The aims of this study were to analyze the predictive factors for the use of intrauterine balloon insertion and to evaluate the efficacy and factors affecting failure of uterine tamponade with a Bakri balloon during cesarean section for abnormal placentation.We reviewed the medical records of 137 patients who underwent elective cesarean section for placenta previa between July 2009 and March 2014. Cesarean section and Bakri balloon insertion were performed by a single qualified surgeon. The Bakri balloon was applied when blood loss during cesarean delivery exceeded 1,000 mL.Sixty-four patients (46.7% required uterine balloon tamponade during cesarean section due to postpartum bleeding from the lower uterine segment, of whom 50 (78.1% had placenta previa totalis. The overall success rate was 75% (48/64 for placenta previa patients. Previous cesarean section history, anterior placenta, peripartum platelet count, and disseminated intravascular coagulopathy all significantly differed according to balloon success or failure (all p<0.05. The drainage amount over 1 hour was 500 mL (20-1200 mL in the balloon failure group and 60 mL (5-500 mL in the balloon success group (p<0.01.Intrauterine tamponade with a Bakri balloon is an adequate adjunct management for postpartum hemorrhage following cesarean section for placenta previa to preserve the uterus. This method is simple to apply, non-invasive, and inexpensive. However, possible factors related to failure of Bakri balloon tamponade for placenta previa patients such as prior cesarean section history, anterior placentation, thrombocytopenia, presence of DIC at the time of catheter insertion, and catheter drainage volume more than 500 mL within 1 hour of catheter placement should be recognized, and the next-line management should be prepared in advance.

  18. Safety and effectiveness of gastric balloons associated with hypocaloric diet for the treatment of obesity

    Directory of Open Access Journals (Sweden)

    M.ª Luisa de Castro

    2013-10-01

    Full Text Available Introduction: 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. Material and methods: 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 ≥ 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 < 0.05. Results: we placed 73 fluid-filled balloons (80.2% and 18 air-filled ones (19.8%. Compared to baseline values, at 6-month 73.7% subjects succeeded, showing significant reductions in weight (13.3 ± 8.8 kg, BMI (5 ± 3.4 kg/m² (p < 0.0001, with% LTW 11 ± 7%. Six and twelve months after retrieval 45.1% and 28.6% patients reached% LTW ≥ 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. Conclusions: 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.

  19. Secondary instabilities of linearly heated falling films

    Institute of Scientific and Technical Information of China (English)

    HU Jun; SUN Dejun; HU Guohui; YIN Xieyuan

    2005-01-01

    Secondary instabilities of linearly heated failing films are studied through three steps. Firstly, the analysis of the primary linear instability on Miladinova's long wave equation of the linearly heated film is performed. Secondly, the similar Landau equation is derived through weak nonlinear theory, and a two-dimensional nonlinear saturation solution of primary instability is obtained within the weak nonlinear domain. Thirdly, the secondary (three-dimensional) instability of the two-dimensional wave is studied by the Floquet theorem.Our secondary instability analysis shows that the Marangoni number has destabilization effect on the secondary instability.

  20. Edge instabilities of topological superconductors

    Science.gov (United States)

    Hofmann, Johannes S.; Assaad, Fakher F.; Schnyder, Andreas P.

    2016-05-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground-state degeneracy. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry-broken phases, which lift the ground-state degeneracy. We examine the instabilities of the flat-band edge states of dx y-wave superconductors by performing a mean-field analysis in the Majorana basis of the edge states. The leading instabilities are Majorana mass terms, which correspond to coherent superpositions of particle-particle and particle-hole channels in the fermionic language. We find that attractive interactions induce three different mass terms. One is a coherent superposition of imaginary s -wave pairing and current order, and another combines a charge-density-wave and finite-momentum singlet pairing. Repulsive interactions, on the other hand, lead to ferromagnetism together with spin-triplet pairing at the edge. Our quantum Monte Carlo simulations confirm these findings and demonstrate that these instabilities occur even in the presence of strong quantum fluctuations. We discuss the implications of our results for experiments on cuprate high-temperature superconductors.

  1. The Chemistry of Beer Instability

    Science.gov (United States)

    Stewart, Graham G.

    2004-01-01

    Brewing of beer, one of the oldest biotechnology industries was one of the earliest processes to be undertaken on commercial basis. Biological instability involves contamination of bacteria, yeast, or mycelia fungi and there is always a risk in brewing that beer can become contaminated by micro-organisms.

  2. Waves and instabilities in plasmas

    CERN Document Server

    Chen Liu

    1987-01-01

    The topics covered in these notes are selective and tend to emphasize more on kinetic-theory approaches to waves and instabilities in both uniform and non-uniform plasmas, students are assumed to have some basic knowledge of plasma dynamics in terms of single-particle and fluid descriptions.

  3. Lending sociodynamics and economic instability

    Science.gov (United States)

    Hawkins, Raymond J.

    2011-11-01

    We show how the dynamics of economic instability and financial crises articulated by Keynes in the General Theory and developed by Minsky as the Financial Instability Hypothesis can be formalized using Weidlich’s sociodynamics of opinion formation. The model addresses both the lending sentiment of a lender in isolation as well as the impact on that lending sentiment of the behavior of other lenders. The risk associated with lending is incorporated through a stochastic treatment of loan dynamics that treats prepayment and default as competing risks. With this model we are able to generate endogenously the rapid changes in lending opinion that attend slow changes in lending profitability and find these dynamics to be consistent with the rise and collapse of the non-Agency mortgage-backed securities market in 2007/2008. As the parameters of this model correspond to well-known phenomena in cognitive and social psychology, we can both explain why economic instability has proved robust to advances in risk measurement and suggest how policy for reducing economic instability might be formulated in an experimentally sound manner.

  4. GENETIC INSTABILITY IN CERVICAL CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    赵旻; 伍欣星; 邱小萍; 李晖; 戴天力; 谭云

    2002-01-01

    Objective: The role of human papillomavirus (HPV) in the development of cervical carcinoma has been clearly established but other factors could be involved in cervical tumorigenesis such as loss of heterozygosity (LOH) and microsatellite instability (MI). The aim of the present study was to investigate the genetic instability in cervical carcinoma tissues and provide evidence for discoveringnew tumor suppressor genes and screening diagnostic molecular marker of cervical carcinoma. Methods: Fifty primary cervical carcinoma samples from high-incidence area were analyzed by PCR for HPV16 infection, LOH and microsatellite instability. Results: HPV16 was detected in 88% of the cases. Sixty-six percent of total cases showed LOH with no more than 3 different loci per case. The highest frequency of the allelic loss was found in D18S474 (18q21, 40.5%). MI was detected in 4 cases (8%) only. Conclusion: Different percentages of LOH on specific chromosomal regions were found and MI was very infrequent in cervical carcinoma. The putative suppressor gene(s) could be located on specific chromosome regions such as 18q, and genetic instability could be involved in cervical tumorigenesis.

  5. Cavitation instabilities in hydraulic machines

    International Nuclear Information System (INIS)

    Cavitation instabilities in hydraulic machines, hydro turbines and turbopump inducers, are reviewed focusing on the cause of instabilities. One-dimensional model of hydro turbine system shows that the overload surge is caused by the diffuser effect of the draft tube. Experiments show that this effect also causes the surge mode oscillations at part load. One dimensional model of a cavitating turbopump inducer shows that the mass flow gain factor, representing the cavity volume increase caused by the incidence angle increase is the cause of cavitation surge and rotating cavitation. Two dimensional model of a cavitating turbopump inducer shows that various modes of cavitation instabilities start to occur when the cavity length becomes about 65% of the blade spacing. This is caused by the interaction of the local flow near the cavity trailing edge with the leading edge of the next blade. It was shown by a 3D CFD that this is true also for real cases with tip cavitation. In all cases, it was shown that cavitation instabilities are caused by the fundamental characteristics of cavities that the cavity volume increases with the decrease of ambient pressure or the increase of the incidence angle

  6. The balloon-borne large aperture submillimeter telescope

    Science.gov (United States)

    Truch, Matthew David Patey

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is designed to produce large (1-100 deg 2 ) maps of the sky at 250, 350, and 500 pm. The balloon platform lifts BLAST above most of the atmosphere, which is nearly opaque in the submillimeter, making BLAST significantly more sensitive than existing ground-based submillimeter telescopes. BLAST has had three successful flights on a high-altitude balloon. This thesis is in three parts. In the first part, the design, construction, and operation of BLAST is described in detail. Specifically, the submillimeter telescope and receiver, the cryogenic system, the various pointing sensors, and the command and control systems are covered. The processes of launching and landing the gondola are also discussed. In the second part, the analysis of BLAST data is discussed, and specifically data from the BLAST05 flight. The process of cleaning and preparing bolometer time-streams for map-making is discussed. The process of calibrating the data, flat-fielding the bolometer responsivity, removing time-varying changes in bolometer responsivity, and absolute flux calibration based on the fluxes of a known astronomical submillimeter source is detailed. Reconstructing the pointing solution from the data from the in-flight pointing sensors is discussed. Finally, combining the calibrated bolometer data with the reconstructed pointing solution to generate maps is described. In the third part, BLAST05 flight data and results are presented. Several compact sources were mapped, including solar system, Galactic, and extragalactic targets. These included Pallas and Saturn in the solar system, K3-50, W 75N, IRAS 20126+4104, CRL 2688, IRAS 21078+5211, LDN 1014, IRAS 21307+5049, IRAS 22134+5834, and IRAS 23011+6126 in the Galaxy, and the galaxies NGC 4565, Mrk 231, and Arp 220. Fluxes and spectral energy distributions (SEDs) of each of these sources at the BLAST wavelengths are presented, and these are compared with previous

  7. Collection of Stratospheric Samples using Balloon-Borne Payload System

    Science.gov (United States)

    Prakash, Ajin; Safonova, Margarita; Murthy, Jayant; Sreejith, A. G.; Kumble, Sheshashayi; Mathew, Joice; Sarpotdar, Mayuresh; Kj, Nirmal; Suresh, Ambily; Chakravortty, Dipshikha; Rangarajan, Annapoorni

    2016-07-01

    Earth's atmosphere at stratospheric altitudes contains dust particles from soil lifted by weather, volcanic dust, man-made aerosols, IDP (Interplanetary Dust Particles) - remnants of comets and asteroids, and even interstellar dust. Satellite observations suggest that approximately 100--300 tons of cosmic dust enter Earth's atmosphere every day. However, very little is known about the microbial life in the upper atmosphere, where conditions are very much similar to that on Mars and possibly on some exoplanets. Stratosphere provides a good opportunity to study the existence or survival of biological life in these conditions. Despite the importance of this topic to astrobiology, stratospheric microbial diversity/survival remains largely unexplored, probably due to significant difficulties in the access and ensuring the absence of contamination of the samples. To conduct a detailed study into this, we are developing the balloon-borne payload system SAMPLE (Stratospheric Altitude Microbiology Probe for Life Existence) to collect dust samples from stratosphere and bring them in an hygienic and uncontaminated manner to a suitable laboratory environment, where further study will be conducted to establish the possibility of microbial life in the upper atmosphere. This balloon-borne payload system will rise through the atmosphere till it reaches an altitude of about 25-30 km above sea level. The payload consists of detachable pre-sterilized sampling chambers designed to collect and contain the dust samples and get them back to the surface without contamination during the flight, a microprocessor and a controller which will determine the altitude of the payload system to actively monitor the opening and closing of the sample collection chambers. For contamination control, we will have two extra chambers, one of which will fly but not open, and one will remain closed on the ground. Other onboard devices include environmental sensors, GPS tracking devices, cameras to monitor

  8. Balloon aortic valvuloplasty as a bridge-to-decision in high risk patients with aortic stenosis: a new paradigm for the heart team decision making

    Science.gov (United States)

    Saia, Francesco; Moretti, Carolina; Dall'Ara, Gianni; Ciuca, Cristina; Taglieri, Nevio; Berardini, Alessandra; Gallo, Pamela; Cannizzo, Marina; Chiarabelli, Matteo; Ramponi, Niccolò; Taffani, Linda; Bacchi-Reggiani, Maria Letizia; Marrozzini, Cinzia; Rapezzi, Claudio; Marzocchi, Antonio

    2016-01-01

    Background Whilst the majority of the patients with severe aortic stenosis can be directly addressed to surgical aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI), in some instances additional information may be needed to complete the diagnostic workout. We evaluated the role of balloon aortic valvuloplasty (BAV) as a bridge-to-decision (BTD) in selected high-risk patients. Methods Between 2007 and 2012, the heart team in our Institution required BTD BAV in 202 patients. Very low left ventricular ejection fraction, mitral regurgitation grade ≥ 3, frailty, hemodynamic instability, serious comorbidity, or a combination of these factors were the main drivers for this strategy. We evaluated how BAV influenced the final treatment strategy in the whole patient group and in each specific subgroup. Results Mean logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 23.5% ± 15.3%, age 81 ± 7 years. In-hospital mortality was 4.5%, cerebrovascular accident 1% and overall vascular complications 4% (0.5% major; 3.5% minor). Of the 193 patients with BTD BAV who survived and received a second heart team evaluation, 72.6% were finally deemed eligible for definitive treatment (25.4% for AVR; 47.2% for TAVI): 96.7% of patients with left ventricular ejection fraction recovery; 70.5% of patients with mitral regurgitation reduction; 75.7% of patients who underwent BAV in clinical hemodynamic instability; 69.2% of frail patients and 68% of patients who presented serious comorbidities. Conclusions Balloon aortic valvuloplasty can be considered as bridge-to-decision in high-risk patients with severe aortic stenosis who cannot be immediate candidates for definitive transcatheter or surgical treatment. PMID:27582761

  9. Basic development of a small balloon-mounted telemetry and its operation system by university students

    Science.gov (United States)

    Yamamoto, Masa-yuki; Kakinami, Yoshihiro; Kono, Hiroki

    In Japan, the high altitude balloon for scientific observation has been continuously launched by JAXA. The balloon has a possibility to reach 50 km altitude without tight environmental condition for onboard equipments, operating with a cost lower than sounding rockets, however, development of the large-scale scientific observation balloons by university laboratories is still difficult. Being coupled with recent improvement of semiconductor sensors, laboratory-basis balloon experiments using small weather balloons has been becoming easily in these years. Owing to an advantage of wide land fields in continental regions, the launch of such small balloons has become to be carried out many times especially in continental countries (e.g. Near Space Ventures, Inc., 2013). Although the balloon is very small as its diameter of 6 feet, excluding its extra buoyancy and the weight of the balloon itself, it is expected that about 2 kg loading capacity is remained for payloads to send it up to about 35 km altitude. However, operation of such balloons in Japan is not in general because precise prediction of a landing area of the payload is difficult, thus high-risk situation for balloon releases is remained. In this study, we aim to achieve practical engineering experiments of weather balloons in Japan to be used for scientific observation within university laboratory level as an educational context. Here we report an approach of developing many devices for a small tethered balloon currently in progress. We evaluated an accuracy of altitude measurement by using a laboratory developed altitude data logger system that consists of a GPS-module and a barometric altimeter. Diameter of the balloon was about 1.4 m. Being fulfilled with about 1440 L helium, it produced buoyancy of about 15.7 N. Taking into account of total weight including the mooring equipments, available payload mass becomes to be about 1100 g. Applying an advantage of a 3D printer of FDM (Fused Deposition Modeling

  10. Coupled Bunch Instabilities in the LHC

    CERN Document Server

    Angal-Kalinin, Deepa

    2002-01-01

    In the LHC, the coupled bunch instabilities will be mainly driven by the RF cavities and the resistive wall effect. The growth times of these instabilities have been estimated taking into consideration the undamped and damped higher order modes of these cavities. These estimates show that the rise times of the longitudinal coupled bunch instabilities are under control. The proposed transverse feed-back system allows the same conclusion to be drawn for the transverse resistive wall instability.

  11. Surge Instability on a Cavitating Propeller

    OpenAIRE

    Duttweiler, Mark E.; Brennen, Christopher E.

    2001-01-01

    This study details experiments investigating a previously unrecognized surge instability on a cavitating propeller in a water tunnel. The surge instability is furst explored through visual observation of the cavitation on the propeller blades and in the tip vortices. Similarities between the instability and previously documented cavitation phenomena are noted. Measurements of the radiated pressure are then obtained, and the acoustic signature of the instability is identified. The magnitud...

  12. LISA: a java API for performing simulations of trajectories for all types of balloons

    Science.gov (United States)

    Conessa, Huguette

    2016-07-01

    LISA (LIbrarie de Simulation pour les Aerostats) is a java API for performing simulations of trajectories for all types of balloons (Zero Pressure Balloons, Pressurized Balloons, Infrared Montgolfier), and for all phases of flight (ascent, ceiling, descent). This library has for goals to establish a reliable repository of Balloons flight physics models, to capitalize developments and control models used in different tools. It is already used for flight physics study software in CNES, to understand and reproduce the behavior of balloons, observed during real flights. It will be used operationally for the ground segment of the STRATEOLE2 mission. It was developed with quality rules of "critical software." It is based on fundamental generic concepts, linking the simulation state variables to interchangeable calculation models. Each LISA model defines how to calculate a consistent set of state variables combining validity checks. To perform a simulation for a type of balloon and a phase of flight, it is necessary to select or create a macro-model that is to say, a consistent set of models to choose from among those offered by LISA, defining the behavior of the environment and the balloon. The purpose of this presentation is to introduce the main concepts of LISA, and the new perspectives offered by this library.

  13. Therapeutic enema for pediatric ileocolic intussusception: using a balloon catheter improves efficacy.

    Science.gov (United States)

    Betz, Bradford W; Hagedorn, Jeffrey E; Guikema, Jeffrey S; Barnes, Courtney L

    2013-10-01

    A therapeutic enema for pediatric intussusception may benefit by using a rectal catheter with an inflated balloon. We compared the efficacy of rectal catheters without and with an inflated balloon for air and liquid enemas. We retrospectively reviewed PACS images and hospital records of children who had a therapeutic enema for intussusception at our institution between January 2006 and May 2011. Sixty-two enemas in 60 children were included. Physician assistants with training in pediatric fluoroscopy and pediatric radiologists were more likely to use air enema (37/41 or 90 %), and general radiologists were more likely to use liquid enema (18/21 or 86 %). However, the reduction rate for air enema overall was only slightly higher than for liquid enema using an inflated balloon catheter (36/40 or 90 % versus 14/17 or 82 %) (P=0.653). For air enema, mean procedure time for successful reductions was shorter with an inflated balloon catheter than with a plastic catheter (7.6 versus 28.2 min) (Pinflated balloon catheter than without inflation (14/17 or 82 % versus 1/5 or 20 %; P=0.021), but the procedure time was not shortened. No procedural complications were directly attributed to using a rectal catheter with an inflated balloon. Using a rectal catheter with an inflated balloon appears to safely shorten the procedure time of a successful air enema and improve the reduction rate of liquid enema. PMID:23748969

  14. Fine tracking system for balloon-borne telescopes

    CERN Document Server

    Ricci, M; Lorenzetti, D

    2011-01-01

    We present the results of a study along with a first prototype of a high precision system (? 1 arcsec) for pointing and tracking light (near-infrared) telescopes on board stratospheric balloons. Such a system is essentially composed by a star sensor and by a star tracker, able to recognize the field and to adequately track the telescope, respectively. We present the software aimed at processing the star sensor image and the predictive algorithm that allows the fine tracking of the source at a sub-pixel level. The laboratory tests of the system are described and its performance is analyzed. We demonstrate how such a device, when used at the focal plane of enough large telescopes (2-4m, F/10), is capable to provide (sub-)arcsec diffraction limited images in the near infrared bands.

  15. Reflood Phenomena in a 5 x 5 Ballooned Rod Bundle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Jae; Kim, Jong Rok; Kim, Kihwan; Moon, S. K. [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    Various experimental programs were carried out for the coolability of an assembly containing a partial blockage in a group of ballooned fuel rods under LOCA conditions. A review on these experimental programs is well documented in. One key distinguished feature of KAERI research activities is the consideration of local power increase owing to fuel relocation, whereas the past experimental program did not consider the effect of fuel relocation. The purpose of this study is to investigate the reflood phenomena in the partial blocked 5 x 5 rod bundle. A series of the forced reflood tests were performed with/without consideration of local power increase by fuel relocation. The experimental data were evaluated with numerical predictions using MARS code. The flow blockage alone has little effect on the peak wall temperature. However, the local power increase by fuel relocation affects considerably the peak wall temperature and the time period during which high wall temperatures continue.

  16. Prototype TIGRE Compton γ-ray balloon-borne telescope

    Science.gov (United States)

    Bhattacharya, D.; O'Neill, T. J.; Akyüz, A.; Samimi, J.; Zych, A. D.

    2004-02-01

    A prototype balloon-borne telescope is being constructed for γ-ray observations in the MeV energy range. The Tracking and Imaging Gamma-Ray Experiment (TIGRE) uses multi-layers of thin silicon detectors to track and measure the energy losses of Compton recoil electrons. When combined with the direction and energy of the Compton scattered γ-ray a unique incident direction for each photon event is determined. This facilitates background rejection, improved sensitivity and image reconstruction. The converter/tracker also serves as an electron-positron pair detector for γ-rays up to 100 MeV. The initial continental US flight will be used to determine the sub-orbital atmospheric backgrounds and search for polarized γ-emission for the Crab pulsar. Longer southern hemisphere flights with an enhanced instrument will map out the 26Al emissions from the galactic center region.

  17. Absence of Bacteria on Coronary Angioplasty Balloons from Unselected Patients

    DEFF Research Database (Denmark)

    Hansen, Gorm Mørk; Nilsson, Martin; Nielsen, Claus Henrik;

    2015-01-01

    Periodontitis is a chronic, bacterially-induced inflammatory disease of the tooth-supporting tissues, which may result in transient bacteremia and a systemic inflammatory response. Periodontitis is associated with coronary artery disease independently of established cardiovascular risk factors......, and translocation of bacteria from the oral cavity to the coronary arteries may play a role in the development of coronary artery disease. Very few studies have used angioplasty balloons for in vivo sampling from diseased coronary arteries, and with varying results. Therefore, the aim of this study was to assess...... patients with stable angina, unstable angina/non-ST elevation myocardial infarction, and ST-elevation myocardial infarction (n = 15 in each group) were collected and analyzed using a PCR assay with high sensitivity and specificity for 16S rRNA genes of the oral microbiome. Despite elimination of extraction...

  18. Reflood Phenomena in a 5 x 5 Ballooned Rod Bundle

    International Nuclear Information System (INIS)

    Various experimental programs were carried out for the coolability of an assembly containing a partial blockage in a group of ballooned fuel rods under LOCA conditions. A review on these experimental programs is well documented in. One key distinguished feature of KAERI research activities is the consideration of local power increase owing to fuel relocation, whereas the past experimental program did not consider the effect of fuel relocation. The purpose of this study is to investigate the reflood phenomena in the partial blocked 5 x 5 rod bundle. A series of the forced reflood tests were performed with/without consideration of local power increase by fuel relocation. The experimental data were evaluated with numerical predictions using MARS code. The flow blockage alone has little effect on the peak wall temperature. However, the local power increase by fuel relocation affects considerably the peak wall temperature and the time period during which high wall temperatures continue

  19. Audit of radiation dose during balloon mitral valvuloplasty procedure

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, Roshan S [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); Chandy, Sunil [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Peace, B S Timothy [Department of Radiology, Christian Medical College, Vellore-632004, TN (India); George, Paul [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); John, Bobby [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India); Pati, Purendra [Department of Cardiology, Christian Medical College, Vellore-632004, TN (India)

    2006-12-15

    Radiation doses to patients during cardiological procedures are of concern in the present day scenario. This study was intended to audit the radiation dose imparted to patients during the balloon mitral valvuloplasty (BMV) procedure. Thirty seven patients who underwent the BMV procedure performed using two dedicated cardiovascular machines were included in the study. The radiation doses imparted to patients were measured using a dose area product (DAP) meter. The mean DAP value for patients who underwent the BMV procedure from one machine was 19.16 Gy cm{sup 2} and from the other was 21.19 Gy cm{sup 2}. Optimisation of exposure parameters and radiation doses was possible for one machine with the use of appropriate copper filters and optimised exposure parameters, and the mean DAP value after optimisation was 9.36 Gy cm{sup 2}.

  20. 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.

  1. Ballooning of CANDU pressure tubes - experiments with degraded tube material

    International Nuclear Information System (INIS)

    Three as-received Zr-2.5% Nb pressure tube specimens and three specimens with eight 0.5 mm deep defects machined on the inside surface were tested in the ballooning test rig at Stern Laboratories Inc. The temperature ramp rate was controlled between 28 K s-1 and 35 K s-1. Temperatures on the outside and inside surfaces of the specimens, and circumferential and longitudinal strains were recorded during the transients. Post-test longitudinal, circumferential and wall thickness strains were measured. All as-received specimens ruptured full-length near the top, i.e., the hottest point. All defected specimens failed at either or both upper defects, one rupture being full-length and the others limited to one to three times the length of the defect. (author). 4 refs., 2 tabs., 15 figs

  2. Initial Results from the ANITA 2006-2007 Balloon Flight

    Energy Technology Data Exchange (ETDEWEB)

    Gorham, P.W.; /Hawaii U.; Allison, P.; /Hawaii U.; Barwick, S.W.; /UC, Irvine; Beatty, J.J.; /Ohio State U.; Besson, D.Z.; /Kansas U.; Binns, W.R.; /Washington U., St. Louis; Chen, C.; /SLAC; Chen, P.; /SLAC; Clem, J.M.; /Delaware U.; Connolly, A.; /University Coll. London; Dowkontt, P.F.; /Washington U., St. Louis; DuVernois, M.A.; /Minnesota U.; Field, R.C.; /SLAC; Goldstein, D.; /UC, Irvine; Goodhue, A.; /UCLA; Hast, C.; /SLAC; Hebert, C.L.; /Hawaii U.; Hoover, S.; /UCLA; Israel, M.H.; /Washington U., St. Louis; Kowalski, J.; /Hawaii U.; Learned, J.G.; /Hawaii U. /Caltech, JPL /Hawaii U. /Minnesota U. /Hawaii U. /Ohio State U. /Hawaii U. /Hawaii U. /UC, Irvine /Taiwan, Natl. Taiwan U. /Caltech, JPL /SLAC /University Coll. London /Ohio State U. /SLAC /Hawaii U. /Hawaii U. /Hawaii U. /UCLA /Delaware U. /Hawaii U. /SLAC /Taiwan, Natl. Taiwan U. /UC, Irvine

    2011-11-16

    We report initial results of the Antarctic Impulsive Transient Antenna (ANITA) 2006-2007 Long Duration Balloon flight, which searched for evidence of the flux of cosmogenic neutrinos. ANITA flew for 35 days looking for radio impulses that might be due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. In our initial high-threshold robust analysis, no neutrino candidates are seen, with no physics background. In a non-signal horizontal-polarization channel, we do detect 6 events consistent with radio impulses from extensive air showers, which helps to validate the effectiveness of our method. Upper limits derived from our analysis now begin to eliminate the highest cosmogenic neutrino models.

  3. Static and quasi-static analysis of lobed-pumpkin balloon

    Science.gov (United States)

    Nakashino, Kyoichi; Sasaki, Makoto; Hashimoto, Satoshi; Saito, Yoshitaka; Izutsu, Naoki

    The present study is motivated by the need to improve design methodology for super pressure balloon with 3D gore design concept, currently being developed at the Scientific Balloon Center of ISAS/JAXA. The distinctive feature of the 3-D gore design is that the balloon film has excess materials not only in the circumferential direction but also in the meridional direction; the meridional excess is gained by attaching the film boundaries to the corresponding tendons of a shorter length with a controlled shortening rate. The resulting balloon shape is a pumpkin-like shape with large bulges formed between adjacent tendons. The balloon film, when fully inflated, develops wrinkles in the circumferential direction over its entire region, so that the stresses in the film are limited to a small amount of uniaxial tension in the circumferential direction while the high meridional loads are carried by re-enforced tendons. Naturally, the amount of wrinkling in the film is dominated by the shortening rate between the film boundaries and the tendon curve. In the 3-D gore design, as a consequence, the shortening rate becomes a fundamental design parameter along with the geometric parameters of the gore. In view of this, we have carried out a series of numerical study of the lobed-pumpkin balloon with varying gore geometry as well as with varying shortening rate. The numerical simula-tions were carried out with a nonlinear finite element code incorporating the wrinkling effect. Numerical results show that there is a threshold value for the shortening rate beyond which the stresses in the balloon film increases disproportionately. We have also carried out quasi-static simulations of the inflation process of the lobed-pumpkin balloon, and have obtained asymmetric deformations when the balloon films are in uniaxial tension state.

  4. Localized Rayleigh Instability in Evaporation Fronts

    OpenAIRE

    Diamant, Haim; Agam, Oded

    2009-01-01

    A qualitatively different manifestation of the Rayleigh instability is demonstrated, where, instead of the usual extended undulations and breakup of the liquid into many droplets, the instability is localized, leading to an isolated narrowing of the liquid filament. The localized instability, caused by a nonuniform curvature of the liquid domain, plays a key role in the evaporation of thin liquid films off solid surfaces.

  5. Observation of Parametric Instability in Advanced LIGO

    CERN Document Server

    Evans, Matthew; Fritschel, Peter; Miller, John; Barsotti, Lisa; Martynov, Denis; Brooks, Aidan; Coyne, Dennis; Abbott, Rich; Adhikari, Rana; Arai, Koji; Bork, Rolf; Kells, Bill; Rollins, Jameson; Smith-Lefebvre, Nicolas; Vajente, Gabriele; Yamamoto, Hiroaki; Derosa, Ryan; Effler, Anamaria; Kokeyama, Keiko; Betzweiser, Joseph; Frolov, Valera; Mullavey, Adam; O`Reilly, Brian; Dwyer, Sheila; Izumi, Kiwamu; Kawabe, Keita; Landry, Michael; Sigg, Daniel; Ballmer, Stefan; Massinger, Thomas J; Staley, Alexa; Mueller, Chris; Grote, Hartmut; Ward, Robert; King, Eleanor; Blair, David; Ju, Li; Zhao, Chunnong

    2015-01-01

    Parametric instabilities have long been studied as a potentially limiting effect in high-power interferometric gravitational wave detectors. Until now, however, these instabilities have never been observed in a kilometer-scale interferometer. In this work we describe the first observation of parametric instability in an Advanced LIGO detector, and the means by which it has been removed as a barrier to progress.

  6. Basic instabilities of collisionless gravitating systems.

    Science.gov (United States)

    Polyachenko, V. L.

    1995-05-01

    The paper presents a short summary of basic instabilities in stellar systems, namely: the Jeans, bar-mode and fire-hose (bending) instabilities. A classification of bar-mode instabilities according to a ratio of the bar pattern angular velocity and the maximal precession speed of nearly-circular stellar orbits is proposed.

  7. Analogy between thermal convective and magnetohydrodynamic instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Valdmanis, Ya.Ya.; Kukainis, O.A.

    1977-01-01

    An examination is made of the analogy between thermo-convective instability and instability produced by various electromagnetic forces both in steady and alternating thermal and electromagnetic fields. An example is given for calculating an assumed bubble instability which could occur in an alternating magnetic field. 17 references.

  8. Solitons versus parametric instabilities during ionospheric heating

    Science.gov (United States)

    Nicholson, D. R.; Payne, G. L.; Downie, R. M.; Sheerin, J. P.

    1984-01-01

    Various effects associated with ionospheric heating are investigated by numerically solving the modified Zakharov (1972) equations. It is shown that, for typical ionospheric parameters, the modulational instability is more important than the parametric decay instability in the spatial region of strongest heater electric field. It is concluded that the modulational instability leads to the formation of solitons, as originally predicted by Petviashvili (1976).

  9. Analysis of actinic flux profiles measured from an ozonesonde balloon

    Science.gov (United States)

    Wang, P.; Allaart, M.; Knap, W. H.; Stammes, P.

    2015-04-01

    A green light sensor has been developed at KNMI to measure actinic flux profiles using an ozonesonde balloon. In total, 63 launches with ascending and descending profiles were performed between 2006 and 2010. The measured uncalibrated actinic flux profiles are analysed using the Doubling-Adding KNMI (DAK) radiative transfer model. Values of the cloud optical thickness (COT) along the flight track were taken from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) Cloud Physical Properties (CPP) product. The impact of clouds on the actinic flux profile is evaluated on the basis of the cloud modification factor (CMF) at the cloud top and cloud base, which is the ratio between the actinic fluxes for cloudy and clear-sky scenes. The impact of clouds on the actinic flux is clearly detected: the largest enhancement occurs at the cloud top due to multiple scattering. The actinic flux decreases almost linearly from cloud top to cloud base. Above the cloud top the actinic flux also increases compared to clear-sky scenes. We find that clouds can increase the actinic flux to 2.3 times the clear-sky value at cloud top and decrease it to about 0.05 at cloud base. The relationship between CMF and COT agrees well with DAK simulations, except for a few outliers. Good agreement is found between the DAK-simulated actinic flux profiles and the observations for single-layer clouds in fully overcast scenes. The instrument is suitable for operational balloon measurements because of its simplicity and low cost. It is worth further developing the instrument and launching it together with atmospheric chemistry composition sensors.

  10. Hands-on Space Exploration through High Altitude Ballooning

    Science.gov (United States)

    Hammergren, Mark; Gyuk, G.

    2010-01-01

    The Adler Planetarium's "Far Horizons" high-altitude ballooning effort serves as the focus for a diverse set of educational activities, including middle school summer camps, a high school summer program (the Astro-Science Workshop), school-year internships for high school students, summer internships for undergraduates, a NSF-funded graduate fellowship, and a thriving public volunteer program. The relatively low costs of both the reusable hardware (less than $1000) and expendable supplies (around $150 per launch) allow us to mount frequent missions throughout the year - and make such a program ideal for replication at institutions of any size. The rapid development schedule for each individual mission permits the cradle-to-grave involvement of short-term participants, making it easy to draw in a wide audience. Students are involved literally in a hands-on manner in all aspects of the construction, launch, tracking, and recovery of simple experimental payloads, which typically include sensors for temperature, pressure, light intensity, and radiation. Stunning imagery provided by onboard cameras can attract significant media interest, which can bring outreach efforts to a very broad audience. Future plans include the design and construction of CubeSats - decimeter-sized picosatellites carried to orbit as secondary payloads. Our first satellite will be a relatively simple Earth-imager, built from commercial, off-the-shelf components. As in the ballooning program, students and volunteers will be involved in all stages of this effort. Once operational, imagery and other data from the satellite will be incorporated into a museum exhibit that will allow visitors to submit target requests. This material is based in part upon work supported by the National Science Foundation under Grant No. 0525995.

  11. Coordinated weather balloon solar radiation measurements during a solar eclipse

    Science.gov (United States)

    2016-01-01

    Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550757

  12. Coordinated weather balloon solar radiation measurements during a solar eclipse.

    Science.gov (United States)

    Harrison, R G; Marlton, G J; Williams, P D; Nicoll, K A

    2016-09-28

    Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. PMID:27550757

  13. Characteristic mechanical properties of balloon-expandable peripheral stent systems

    International Nuclear Information System (INIS)

    Purpose: To measure in vitro geometric-mechanical characteristics of balloon-expandable peripheral stent systems for determining suitability for specific vascular regions. Materials and Methods: Balloon-expandable stents including their delivery systems manufactured by Guidant (OTW MegalinkTM), Inflow Dynamics (Antares), Medtronic (AVE BridgeTM), Biotronik (PeironTM) and Cordis (Corinthian IQTM) were selected for this study. When expanded, all stents had a nominal diameter of 8 mm. The length was 38-40 mm. Stent profile, trackability, length change on expansion, stiffness, elastic recoil, and radio-opacity in the crimped and expanded state of these stent systems were determined with specially developed test methods. Results: The Corinthian IQTM, MegalinkTM and PeironTM required the smallest force to pass through the vascular model. While the BridgeTM system had the largest profile with a diameter of 2.430 mm, all other stent systems had a significantly smaller diameter ranging from 1.970 mm for the PeironTM to 2.078 mm for the Corinthian IQTM. In the distal region of the stent delivery system, the MegalinkTM was the most flexible and the BridgeTM system the stiffest. Elastic recoil for all stents was in the range of 2.5% to 3.5%, with the exception of the BridgeTM stent, which had an elastic recoil of 4.79%. The Corinthian IQTM stent had noticeably the highest radial stiffness. In the expanded condition, the PeironTM was the most flexible while the Corinthian IQTM and AntaresTM were found to be the stiffest. Length change (shrinkage on expansion) ranged from 0.54 to 6.57%, with the exception of the Corinthian IQ, which shrunk >7 mm (18.5%) on expansion. All stent systems in the crimped and expanded state were readily visible radiographically. (orig.)

  14. Amplitude Equation for Instabilities Driven at Deformable Surfaces - Rosensweig Instability

    Science.gov (United States)

    Pleiner, Harald; Bohlius, Stefan; Brand, Helmut R.

    2008-11-01

    The derivation of amplitude equations from basic hydro-, magneto-, or electrodynamic equations requires the knowledge of the set of adjoint linear eigenvectors. This poses a particular problem for the case of a free and deformable surface, where the adjoint boundary conditions are generally non-trivial. In addition, when the driving force acts on the system via the deformable surface, not only Fredholm's alternative in the bulk, but also the proper boundary conditions are required to get amplitude equations. This is explained and demonstrated for the normal field (or Rosensweig) instability in ferrofluids as well as in ferrogels. An important aspect of the problem is its intrinsic dynamic nature, although at the end the instability is stationary. The resulting amplitude equation contains cubic and quadratic nonlinearities as well as first and (in the gel case) second order time derivatives. Spatial variations of the amplitudes cannot be obtained by using simply Newell's method in the bulk.

  15. Balloon catheter dilatation of esophageal strictures in children and an infant

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Kyung Mo; Choe, Yeon Hyeon; Kim, In One [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1986-10-15

    Severe postoperative strictures in two children and an infant and mild postoperative stricture in a child were treated with balloon catheter. A child with post-fundoplication stricture showed symptomatic improvement. Anastomotic strictures after esophageal atresia repair in an infant and a child were successfully dilated with improved luminal diameter and symptoms. In a child with mild postoperative stricture, balloon dilatation was performed to prevent stricture of the anastomotic site. Radiological esophageal dilatation using balloon catheters is a safe effective method for dilating symptomatic esophageal strictures which obviates surgery and allows subsequent standard bougienage.

  16. Randomised comparison of coronary stenting with and without balloon predilatation in selected patients

    OpenAIRE

    Le Breton, H; Boschat, J; Commeau, P; Brunel, P.; Gilard, M; Breut, C; Bar, O.; Geslin, P; Tirouvanziam, A; Maillard, L.; Moquet, B; Barragan, P.; Dupouy, P.; Grollier, G; Berland, J.

    2001-01-01

    BACKGROUND—The SWIBAP (stent without balloon predilatation) prospective randomised trial was designed to compare direct coronary stenting with stenting preceded by lesion predilatation with an angioplasty balloon.
OBJECTIVE—To determine the feasibility and safety of direct stenting in non-complex coronary lesions in a prospective study.
PATIENTS AND DESIGN—All patients  3.0 mm, who granted their informed consent, were randomised into the trial. In group I, the stent was placed without balloon...

  17. Placing Marangoni instabilities under arrest

    CERN Document Server

    Bhamla, M Saad

    2016-01-01

    Soap bubbles occupy the rare position of delighting and fascinating both young children and scientific minds alike. Sir Isaac Newton, Joseph Plateau, Carlo Marangoni, and Pierre-Gilles de Gennes, not to mention countless others, have discovered remarkable results in optics, molecular forces and fluid dynamics from investigating this seemingly simple system. We present here a compilation of curiosity-driven experiments that systematically investigate the surface flows on a rising soap bubble. From childhood experience, we are familiar with the vibrant colors and mesmerizing display of chaotic flows on the surface of a soap bubble. These flows arise due to surface tension gradients, also known as Marangoni flows or instabilities. In Figure 1, we show the surprising effect of layering multiple instabilities on top of each other, highlighting that unexpected new phenomena are still waiting to be discovered, even in the simple soap bubble.

  18. Mechanical Instabilities of Biological Tubes

    CERN Document Server

    Hannezo, Edouard; Prost, Jacques; 10.1103/PhysRevLett.109.018101

    2012-01-01

    We study theoretically the shapes of biological tubes affected by various pathologies. When epithelial cells grow at an uncontrolled rate, the negative tension produced by their division provokes a buckling instability. Several shapes are investigated : varicose, enlarged, sinusoidal or sausage-like, all of which are found in pathologies of tracheal, renal tubes or arteries. The final shape depends crucially on the mechanical parameters of the tissues : Young modulus, wall-to-lumen ratio, homeostatic pressure. We argue that since tissues must be in quasistatic mechanical equilibrium, abnormal shapes convey information as to what causes the pathology. We calculate a phase diagram of tubular instabilities which could be a helpful guide for investigating the underlying genetic regulation.

  19. On dynamical (black hole) instabilities

    CERN Document Server

    Coutant, Antonin; Parentani, Renaud

    2016-01-01

    Black hole dynamical instabilities have been mostly studied in specific models. To display their common features, we study the general properties of the complex frequency modes which are responsible for such instabilities. We show that they are square integrable, have a vanishing conserved norm, and appear in mode doublets or quartets. We also study how they appear in the spectrum and how their complex frequencies subsequently evolve when varying some external parameter. When working on an infinite domain, they appear from the reservoir of quasi-normal modes obeying outgoing boundary conditions. This is illustrated by generalizing, in a non-positive definite Krein space, a solvable model (Friedrichs model) which originally describes the appearance of a resonance when coupling an isolated system to a mode continuum. In a finite spatial domain instead, they arise from the fusion of two real frequency modes with opposite norms, through a process that closely resembles avoided crossing.

  20. Instability of supersymmetric microstate geometries

    CERN Document Server

    Eperon, Felicity C; Santos, Jorge E

    2016-01-01

    We investigate the classical stability of supersymmetric, asymptotically flat, microstate geometries with five non-compact dimensions. Such geometries admit an "evanescent ergosurface": a timelike hypersurface of infinite redshift. On such a surface, there are null geodesics with zero energy relative to infinity. These geodesics are stably trapped in the potential well near the ergosurface. We present a heuristic argument indicating that this feature is likely to lead to a nonlinear instability of these solutions. We argue that the precursor of such an instability can be seen in the behaviour of linear perturbations: nonlinear stability would require that all linear perturbations decay sufficiently rapidly but the stable trapping implies that some linear perturbation decay very slowly. We study this in detail for the most symmetric microstate geometries. By constructing quasinormal modes of these geometries we show that generic linear perturbations decay slower than any inverse power of time.

  1. Instability of vortex pair leapfrogging

    DEFF Research Database (Denmark)

    Tophøj, Laust; Aref, Hassan

    2013-01-01

    linear system with time-periodic coefficients and perform a Floquet analysis. We find transition from linearly unstable to stable leapfrogging at α = φ2 ≈ 0.381966, where is the golden ratio. Acheson also suggested that there was a sharp transition between a "disintegration" instability mode, where two......Leapfrogging is a periodic solution of the four-vortex problem with two positive and two negative point vortices all of the same absolute circulation arranged as co-axial vortex pairs. The set of co-axial motions can be parameterized by the ratio 0 ... pair passes through the other. Leapfrogging occurs for α > σ2, where is the silver ratio. The motion is known in full analytical detail since the 1877 thesis of Gröbli and a well known 1894 paper by Love. Acheson ["Instability of vortex leapfrogging," Eur. J. Phys.21, 269-273 (2000...

  2. Stretching Folding Instability and Nanoemulsions

    CERN Document Server

    Chan, Chon U

    2009-01-01

    Here we show a folding-stretching instability in a microfluidic flow focusing device using silicon oil (100cSt) and water. The fluid dynamics video demonstrates an oscillating thread of oil focused by two co-flowing streams of water. We show several high-speed sequences of these oscillations with 30,000 frames/s. Once the thread is decelerated in a slower moving pool downstream an instability sets in and water-in-oil droplets are formed. We reveal the details of the pinch-off with 500,000 frames/s. The pinch-off is so repeatable that complex droplet patterns emerge. Some of droplets are below the resolution limit, thus smaller than 1 micrometer in diameter.

  3. Statistical theory of thermal instability

    CERN Document Server

    Illarionov, A F

    1997-01-01

    A new statistical approach is presented to study the thermal instability process of optically thin unmagnetized plasma. In this approach the time evolution of mass distribution function over temperature is calculated. This function characterizes the statistical properties of the multiphase medium of arbitrary spaced three-dimensional structure of arbitrary temperature perturbations. We construct our theory under the isobarical condition (P=const over space), which is satisfied in the short wavelength limit. The developed theory is illustrated in the case of thermal instability of a slowly expanding interstellar cloud. Numerical solutions of equations of the statistical theory are constucted and compared with hydrodynamical solutions. The results of both approaches are identical in the short wavelength range when the isobarity condition is satisfied. Also the limits of applicability of the statistical theory are estimated. The possible evolution of initial spectrum of perturbations is discussed. The proposed t...

  4. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth

    2011-01-21

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations of the velocities of spheres to increase with the size of the container, whereas experiments found no such variation. Two ideas have increased our understanding. First, the correlation length of the velocity fluctuations was found experimentally to be 20 interparticle separations. Second, in dilute suspensions, a vertical variation in the concentration due to the spreading of the front with the clear fluid can inhibit the velocity fluctuations. In a very dilute regime, a homogeneous suspension of fibers suffers a spontaneous instability in which fast descending fiber-rich columns are separated by rising fiber-sparse columns. In a semidilute regime, the settling is hindered, more so than for spheres. © 2011 by Annual Reviews. All rights reserved.

  5. Feedback control of resistive instabilities

    International Nuclear Information System (INIS)

    Resistive instabilities are responsible for much of the global behavior and the determination of the possible domains of operation of tokamaks. Their successful control could have definite advantages, even making available new regimes of operation. Elimination of sawtoothing might allow operation with higher currents and more peaked current profiles, with q on axis well below unity. In this work different feedback schemes are explored. Simple analytical derivations of the effects of local heating and current drive feedback are presented. Although control of modes with m greater than or equal to 2 is fairly straightforward, the control of the m = 1 mode is more difficult because of its proximity to ideal instability. The most promising scheme utilizes high energy trapped particles. 20 refs., 3 figs

  6. MD 751: Train Instability Threshold

    CERN Document Server

    Carver, Lee Robert; Metral, Elias; Salvant, Benoit; Levens, Tom; Nisbet, David; Zobov, M; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the octupole current thresholds for stability for a single bunch, and then make an immediate comparison (with the same operational settings) for a train of 72 bunches separated by 25ns. From theory, the expected thresholds should be similar. Any discrepancy between the two cases will be of great interest as it could indicate the presence of additional mechanisms that contribute to the instability threshold, for example electron cloud.

  7. Chromosomal instability determines taxane response

    OpenAIRE

    Swanton, Charles; Nicke, Barbara; Schuett, Marion; Eklund, Aron C.; Ng, Charlotte; Li, Qiyuan; Hardcastle, Thomas; Lee, Alvin; Roy, Rajat; East, Philip; Kschischo, Maik; Endesfelder, David; Wylie, Paul; Kim, Se Nyun; Chen, Jie-Guang

    2009-01-01

    Microtubule-stabilizing (MTS) agents, such as taxanes, are important chemotherapeutics with a poorly understood mechanism of action. We identified a set of genes repressed in multiple cell lines in response to MTS agents and observed that these genes are overexpressed in tumors exhibiting chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells....

  8. Experiences with Extreme Monetary Instability

    OpenAIRE

    Dornbusch, Rudiger

    1990-01-01

    In early 1990, Argentina, Brazil, Peru, Yugoslavia and Poland were experiencing extreme instability or, at least, the early stages of stabilization. Other countries, like Bolivia, had already run the course and stabilized or, like Mexico, had avoided the extreme experience and opted for stabilization promptly and decisively. The lessons from these case studies, and from the earlier experiences of the 1920s and 1940s, have still to be drawn. Exactly the same themes come up each time. The paper...

  9. Bifurcations, instabilities, degradation in geomechanics

    CERN Document Server

    Exadaktylos, George

    2007-01-01

    Leading international researchers and practitioners of bifurcations and instabilities in geomechanics debate the developments and applications which have occurred over the last few decades. The topics covered include modeling of bifurcation, structural failure of geomaterials and geostructures, advanced analytical, numerical and experimental techniques, and application and development of generalised continuum models etc. In addition analytical solutions, numerical methods, experimental techniques, and case histories are presented. Beside fundamental research findings, applications in geotechni

  10. Polygonal instabilities on interfacial vorticities

    CERN Document Server

    Labousse, Matthieu

    2015-01-01

    We report the results of a theoretical investigation of the stability of a toroidal vortex bound by an interface. Two distinct instability mechanisms are identified that rely on, respectively, surface tension and fluid inertia, either of which may prompt the transformation from a circular to a polygonal torus. Our results are discussed in the context of three experiments, a toroidal vortex ring, the hydraulic jump, and the hydraulic bump.

  11. Single-bunch longitudinal instability

    International Nuclear Information System (INIS)

    A theoretical analysis is given of the recently observed microwave instability in storage rings. It is shown that one expects a threshold proportional to impedance R/sub S/ in the limit of very large or small resonator bandwidths, with the threshold lower by the bunching factor for the large bandwidth case. For intermediate bandwidths, the threshold should be proportional to the area under the resonance curve, so de-Qing resonators will have little effect in this region

  12. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

    Bykov, A M; Malkov, M A; Osipov, S M

    2013-01-01

    Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

  13. Ruptured high flow gastric varices with an intratumoral arterioportal shunt treated with balloon-occluded retrograde transvenous obliteration during temporary balloon occlusion of a hepatic artery

    Institute of Scientific and Technical Information of China (English)

    Motoki Nakai; Morio Sato; Hirohiko Tanihata; Tetsuo Sonomura; Shinya Sahara; Nobuyuki Kawai; Masashi Kimura; Masaki Terada

    2006-01-01

    A patient presented with hematemesis due to gastric variceal bleeding with an intratumoral arterioportal shunt. Contrast-enhanced CT revealed gastric varices and hepatocellular carcinoma with tumor thrombi in the right portal vein. Angiography and angio-CT revealed a marked intratumoral arterioportal shunt accompanied with reflux into the main portal vein and gastric varices. Balloon-occluded retrograde venography from the gastro-renal shunt showed no visualization of gastric varices due to rapid blood flow through the intratumoral arterioportal shunt. The hepatic artery was temporarily occluded with a balloon catheter to reduce the blood flow through the arterioportal shunt, and then concurrent balloon-occluded retrograde transvenous obliteration (BRTO) was achieved. Vital signs stabilized immediately thereafter, and contrast-enhanced CT revealed thrombosed gastric varices. Worsening of hepatic function was not recognized. BRTO combined with temporary occlusion of the hepatic artery is a feasible interventional procedure for ruptured high flow gastric varices with an intratumoral arterioportal shunt.

  14. The prevention and management of complications during and immediately after percutaneous balloon mitral valvuloplasty

    International Nuclear Information System (INIS)

    Objective: To approach the cause and treatment of complication during and immediately after percutaneous balloon mitral valvuloplasty. Methods: One thousand three hundred and eleven patients with mitral stenosis were treated by percutaneous transseptal balloon mitral valvuloplasty. Among them, 42 patients with complications were retrospectively analyzed. Results: The overall complications rate was 3.2% (42/1311) including atrial fibrillation 0.8% (10/1311), acute pericardial tamponade 0.31% (4/1311), severe mitral insufficiency 0.46% (6/1311), femoral arterial venous fistula 0.69% (9/1311), acute pulmonary edema and iatrogenic atrial septal defect 0.23% (3/1311), respectively. Coronary air embolism, arterial thrombosis and transient cerebrovascular accident was 0.15% (2/1311) for every other one. Balloon rupture was 0.08%(1/1311). Conclusions: The complications of percutaneous balloon mitral valvuloplasty rarely occur. It is a safe and efficient nonsurgical method for treating rheumatic mitral stenosis

  15. Demonstrating Classical Conditioning in Introductory Psychology: Needles Do Not Always Make Balloons Pop!

    Science.gov (United States)

    Vernoy, Mark W.

    1987-01-01

    Describes a method of teaching classical conditioning to an introductory psychology class which involves demonstrating the conditioned response that occurs when a needle pierces, but does not pop, a balloon. (GEA)

  16. Optical coherence tomography layer thickness characterization of a mock artery during angioplasty balloon deployment

    Science.gov (United States)

    Azarnoush, Hamed; Vergnole, Sébastien; Boulet, Benoît; Lamouche, Guy

    2011-03-01

    Optical coherence tomography (OCT) is used to study the deformation of a mock artery in an angioplasty simulation setup. An OCT probe integrated in a balloon catheter provides intraluminal real-time images during balloon inflation. Swept-source OCT is used for imaging. A 4 mm semi-compliant polyurethane balloon is used for experiments. The balloon is inflated inside a custom-built multi-layer artery phantom. The phantom has three layers to mock artery layers, namely, intima, media and adventitia. Semi-automatic segmentation of phantom layers is performed to provide a detailed assessment of the phantom deformation at various inflation pressures. Characterization of luminal diameter and thickness of different layers of the mock artery is provided for various inflation pressures.

  17. Balloon-Borne, High-Energy Astrophysics: Experiences from the 1960s to the 1980s

    Science.gov (United States)

    Fishman, Gerald J.

    2008-01-01

    Observational high-energy astrophysics in the hard-x-ray and gamma-ray regions owes its development and initial successes to the balloon-borne development of detector systems, as well as pioneering observations, primarily in the timeframe from the 1960s to the 1990s. I will describe some of the first observations made by the Rice University balloon group in the 1960s, including the impetus for these observations. The appearance of SN 1987a led to several balloon-flight campaigns, sponsored by NASA, from Alice Springs, Australia in 1987 and 1988. During the 1980s, prototypes of instruments for the Compton Gamma Ray Observatory were flown on many balloon flights, which greatly enhanced the success of that mission.

  18. Sub-Scale Re-entry Capsule Drop via High Altitude Balloons Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High-altitude balloon flights are an inexpensive method used to lift payloads to high altitudes. Federal Aviation Administration (FAA) regulations permit payloads...

  19. Novel Ultralow-Weight Metal Rubber Sensor System for Ultra Long-Duration Scientific Balloons Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic proposes to develop an innovative, ultralow mass density, and non-intrusive sensor system for ultra long duration balloons that will operate in the most...

  20. Integrating BalloonSAT and Atmospheric Dynamic Concepts into the Secondary Classroom

    Science.gov (United States)

    Fong, B. N.; Kennon, J. T.; Roberts, E.

    2016-05-01

    Arkansas BalloonSAT is an educational outreach and scientific research program that is part of Arkansas State University in Jonesboro, AR. The following is a unit of instruction to incorporate BalloonSAT measurements into secondary science classes. Students interpret graphs and identify several atmospheric trends and properties of a typical balloon flight. Students engage critical thinking skills in developing and answering their own questions relevant to the BalloonSAT program. Prerequisite concepts students should know are how to interpret graphs and unit conversions. Students should have a basic understanding of gravity, units of temperature and distance, and error in measurements. The unit is designed for one week after end-of-course exams and before the end of school. The unit may take two to five 50-minute periods, depending on how many activities are completed.

  1. Induced Radioactivity Measured in a Germanium Detector After a Long Duration Balloon Flight

    Science.gov (United States)

    Starr, R.; Evans, L. G.; Floyed, S. R.; Drake, D. M.; Feldman, W. C.; Squyres, S. W.; Rester, A. C.

    1997-01-01

    A 13-day long duration balloon flight carrying a germanium detector was flown from Williams Field, Antartica in December 1992. After recovery of the payload the activity induced in the detector was measured.

  2. Environmental effects of the US Antarctic Program`s use of balloons in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    McCold, L.N.; Eddlemon, G.K.; Blasing, T.J.

    1995-06-01

    The USAP uses balloons in Antarctica to conduct scientific research, to facilitate safe air transport, and to provide data for global weather predictions. However, there is the possibility that balloons or their payloads may adversely affect Antarctic fauna or flora. The purpose of this study is to provide background information upon which the USAP may draw when complying with its responsibilities under the National Environmental Policy Act of 1969, the Antarctic Treaty, and the Madrid Protocol.

  3. Modeling the ascent of sounding balloons: derivation of the vertical air motion

    Directory of Open Access Journals (Sweden)

    A. Gallice

    2011-06-01

    Full Text Available A new model to describe the ascent of sounding balloons in the troposphere and lower stratosphere (up to ~30–35 km altitude is presented. Contrary to previous models, detailed account is taken of both the variation of the drag coefficient with altitude and the heat imbalance between the balloon and the atmosphere. To compensate for the lack of data on the drag coefficient of sounding balloons, a reference curve for the relationship between drag coefficient and Reynolds number is derived from a dataset of flights launched during the Lindenberg Upper Air Methods Intercomparisons (LUAMI campaign. The transfer of heat from the surrounding air into the balloon is accounted for by solving the radial heat diffusion equation inside the balloon. The potential applications of the model include the forecast of the trajectory of sounding balloons, which can be used to increase the accuracy of the match technique, and the derivation of the air vertical velocity. The latter is obtained by subtracting the ascent rate of the balloon in still air calculated by the model from the actual ascent rate. This technique is shown to provide an approximation for the vertical air motion with an uncertainty error of 0.5 m s−1 in the troposphere and 0.2 m s−1 in the stratosphere. An example of extraction of the air vertical velocity is provided in this paper. We show that the air vertical velocities derived from the balloon soundings in this paper are in general agreement with small-scale atmospheric velocity fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions measured during the SUCCESS campaign (Subsonic Aircraft: Contrail and Cloud Effects Special Study in the orographically unperturbed mid-latitude middle troposphere.

  4. Laceration of anterior mitral leaflet postpercutaneous balloon mitral valvuloplasty for rheumatic mitral stenosis

    OpenAIRE

    Jadoon, Mehmood; Roberts, M. J.; Dixon, L.; Jones, Mark

    2012-01-01

    A 37-year-old Caucasian female with known rheumatic mitral stenosis was admitted for Balloon mitral valvuloplasty which was complicated with a laceration of anterior mitral leaflet (A2 scallop) resulting in severe mitral regurgitation. Intra-aortic balloon pump (IABP) was instituted and the patient was referred for emergency mitral surgery. During surgery anterior mitral leaflet was excised. Most of the posterior leaflet was preserved. Mitral valve was replaced with St Jude mitral mechanical ...

  5. Variceal bleeding from ileum identified and treated by single balloon enteroscopy

    Institute of Scientific and Technical Information of China (English)

    Mario Traina; Ilaria Tarantino; Luca Barresi; Filippo Mocciaro

    2009-01-01

    We report a case of acute uncontrolled gastrointestinal bleeding in a patient with liver cirrhosis. The upper and lower endoscopy were negative for bleeding lesions. We decided to perform the examination of the small bowel using single-balloon enteroscopy. The lower enteroscopy revealed signs of bleeding from varices of the ileum. In this report, we showed that the injection of a sclerosant solution can be accomplished using a freehand technique via the single balloon enteroscopy.

  6. Drug-Coated Balloon Treatment of Very Late Stent Thrombosis Due to Complicated Neoatherosclerosis

    Science.gov (United States)

    Alfonso, Fernando; Bastante, Teresa; Cuesta, Javier; Benedicto, Amparo; Rivero, Fernando

    2016-01-01

    We describe the treatment of a patient presenting with very-late stent thrombosis with the use of a drug-coated balloon. In this patient, optical coherence tomography disclosed that ruptured and complicated neoatherosclerosis was the underlying substrate responsible for the episode of very-late stent thrombosis. The potential use of drug-coated balloons in this unique scenario is discussed. PMID:27409130

  7. Identification of cerebral response to balloon distention of the bile duct

    Institute of Scientific and Technical Information of China (English)

    Masafumi; Suyama; Yoshihiro; Kubokawa; Yuuji; Matsumura; Koichi; Inami; Sumio; Watanabe; Eiji; Kirino

    2010-01-01

    AIM: To identify the brain loci that process human biliary sensation. METHODS: In 6 patients (age range: 42-74 years; 4 men), who underwent percutaneous transhepatic biliary drainage (PTBD), the distal biliary tract was stimulated by repeatedly inflating the balloon of the PTBD catheter so that it reached volumes that produced a definite painless sensation. The functional magnetic resonance imaging (fMRI) of the cortical response to biliary sensation was examined. RESULTS: Biliary balloon stimulation elicit...

  8. Expression of glutamine synthetase in balloon cells: a basis of their antiepileptic role?

    Science.gov (United States)

    Buccoliero, Anna Maria; Barba, Carmen; Giordano, Flavio; Baroni, Gianna; Genitori, Lorenzo; Guerrini, Renzo; Taddei, Gian Luigi

    2015-01-01

    Glutamine synthetase is an enzyme involved in the clearance of glutamate, the most potent excitatory neurotransmitter. We studied the immunohistochemical expression of glutamine synthetase in neocortical samples from 5 children who underwent surgery for pharmacoresistant epilepsy and a histological diagnosis of focal cortical dysplasia IIb. In all cases, balloon cells, but not dysmorphic neurons, were immunopositive for glutamine synthetase. This finding suggests that balloon cells can be involved in the neutralization of glutamate and play a protective anti-seizure role.

  9. A New Type of Captive Balloon for Vertical Meteorological Observation in Urban Area

    Science.gov (United States)

    Nakamura, M.; Sakai, S.; Ono, K.

    2010-12-01

    Many meteorological observations in urban area have been made in recent years in order to investigate the mechanism of heat island. However, there are few data of cooling process in urban area. For this purpose, high density observations in both space and time are required. Generally vertical meteorological observations can be made by towers, radars, balloons. These methods are limited by urban area conditions. Among these methods, a captive balloon is mainly used to about a hundred meter from ground in a vertical meteorological observation. Small airships called kytoons or advertising balloons, for example. Conventional balloons are, however, influenced by the wind and difficult to keep the specified position. Moreover, it can be dangerous to conduct such observations in the highly build-up area. To overcome these difficulties, we are developing a new type of captive balloon. It has a wing form to gain lift and keep its position. It is also designed small to be kept in a carport. It is made of aluminum film and polyester cloth in order to attain lightweight solution. We have tried floating a balloon like NACA4424 for several years. It was difficult to keep a wing form floating up over 100 meters from ground because internal pressure was decreased by different temperature. The design is changed in this year. The balloon that has wing form NACA4415 is similar in composition to an airplane. It has a big gasbag with airship form and two wing form. It is able to keep form of a wing by high internal pressure. We will report a plan for the balloon and instances of some observations.

  10. 24 Hour ST Segment Analysis in Transient Left Ventricular Apical Ballooning

    OpenAIRE

    Frank Bode; Christof Burgdorf; Heribert Schunkert; Volkhard Kurowski

    2013-01-01

    OBJECTIVE: The etiologic basis of transient left ventricular apical ballooning, a novel cardiac syndrome, is not clear. Among the proposed pathomechanisms is coronary vasospasm. Long-term ST segment analysis may detect vasospastic episodes but has not been reported. METHODS: 30 consecutive patients with transient left ventricular apical ballooning, left ventricular dysfunction and normal or near-normal coronary arteries were investigated. A 24-hour Holter ECG was obtained after emergency admi...

  11. Balloon Analogue Risk Task to assess decision-making in Acquired Brain Injury

    OpenAIRE

    Marina Areny Balagueró; Mercè Jodar Vicente; Alberto García Molina; Josep María Tormos; Teresa Roig Rovira

    2016-01-01

    Introduction: Although impairment in decision-making is a frequent consequence of frontal lobe injury, few instruments evaluate decision-making in patients with acquired brain injury (ABI). Most are difficult to use and require a well-preserved ability of complex verbal comprehension and executive functions. We propose the Balloon Analogue Risk Task (BART) as an alternative instrument to evaluate decision-making in ABI. Material and Methods: Balloon Analogue Risk Task (BART) and Iowa Gambling...

  12. Characterization of Pebax angioplasty balloon surfaces with AFM, SEM, TEM, and SAXS.

    Science.gov (United States)

    Warner, Jacob A; Forsyth, Bruce; Zhou, Fang; Myers, Jason; Frethem, Chris; Haugstad, Greg

    2016-04-01

    In the medical device industry, angioplasty balloons have been widely used in the less invasive treatment of heart disease by expanding and relieving clogged structures in various arterial segments. However, new applications using thin coatings on the balloon surface have been explored to enhance therapeutic value in the delivery of pharmaceuticals (drug-elution) or control thermal energy output (RF ablation). In this study, angioplasty balloon materials comprised of poly(ether-block-amide) (Pebax) were investigated via atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and small-angle X-ray scattering (SAXS) to characterize physical properties at the balloon surface that may affect coating adhesion. The soft segment of this Pebax 1074 material is polyethylene oxide (PEO) and the hard segment is nylon-12. The morphology of the hard segments of this block co-polymer are found via AFM stiffness measurements to be (40 ± 20) nm by (300 ± 150) nm and are oriented parallel to the surface of the balloon. SAXS measurements found the lamellar spacing to be (18.5 ± 0.5) nm, and demonstrate a preferential orientation in agreement with TEM and AFM measurements. Fixation of this balloon in resin, followed by cryo-sectioning is shown to provide a novel manner in which to investigate surface characteristics on the balloon such as material or coating thickness as well as uniformity in comparison to the bulk structure. These outputs were deemed critical to improve overall balloon processing such as molding and surface treatment options for robust designs toward better procedural outcomes targeting new therapeutic areas. PMID:25891789

  13. Double-Balloon Catheter for Isolated Liver Perfusion: An Experimental Study

    International Nuclear Information System (INIS)

    Purpose: Further development of a previously described interventional method for isolated liver perfusion (ILP) with a new double-lumen balloon catheter, and evaluation of the side-effects of such isolation.Methods: In six pigs a double-balloon occlusion catheter was placed via the transjugular approach with its tip in the portal vein. One of the balloons was positioned in the inferior vena cava (IVC), cranial to the origin of the hepatic veins and the other balloon in the portal vein. By the transfemoral approach, a single-balloon occlusion catheter was placed in the IVC caudal to the origin of the hepatic veins. A third catheter was placed by the transfemoral route with the occlusion balloon in the proper hepatic artery. After inflation of all balloons 99Tcm-labelled human serum albumin was recirculated through the liver. The isolation was evaluated by repeated measurement of radioactivity levels in peripheral blood. Laboratory tests of liver and pancreas function, and hemoglobin, were taken before, at the end of, and 3 days after the procedure. Blood gases were tested at the beginning and end of the procedure.Results: One pig died during the procedure due to technical failure and was excluded from the study. In the other pigs leakage from the isolated liver to the systemic circulation increased slowly, up to 9.7% (mean) during 30 min of recirculation of the perfusate through the liver. Laboratory tests were normal in all pigs except insignificant acidosis directly after the procedure and the slight elevation of s-ALAT after 3 days.Conclusions: Only minor leakage from the liver to the systemic circulation was noted during ILP performed with a new, double-balloon catheter. There were no serious side effects

  14. The Cosmic Foreground Explorer (COFE): A balloon-borne microwave polarimeter to characterize polarized foregrounds

    OpenAIRE

    Leonardi, Rodrigo; Williams, Brian; Bersanelli, Marco; Ferreira, Ivan; Lubin, Philip M.; Meinhold, Peter R.; O'Neill, Hugh,; Stebor, Nathan C.; Villa, Fabrizio; Villela, Thyrso; Wuensche, Carlos A.

    2007-01-01

    The COsmic Foreground Explorer (COFE) is a balloon-borne microwave polarime- ter designed to measure the low-frequency and low-l characteristics of dominant diffuse polarized foregrounds. Short duration balloon flights from the Northern and Southern Hemispheres will allow the telescope to cover up to 80% of the sky with an expected sensitivity per pixel better than 100 $\\mu K / deg^2$ from 10 GHz to 20 GHz. This is an important effort toward characterizing the polarized foregrounds for future...

  15. Pulmonary valve regurgitation following balloon valvuloplasty for pulmonary valve stenosis: Single center experience

    Directory of Open Access Journals (Sweden)

    Asim Yousuf Al Balushi

    2013-01-01

    Full Text Available Background: Pulmonary valve regurgitation following balloon valvuloplasty for moderate to severe pulmonary valve stenosis is a known late outcome of this procedure. Objective: The aim of the study was to characterise the status of pulmonary regurgitation on follow up after pulmonary valve balloon dilatation (PVBD, and to study the determinant of the severity of PR. Materials and Methods: We retrospectively reviewed 50 consecutive patients, aged 2 days to 18 years, with isolated pulmonary valve stenosis, who had undergone PVBD in 2004-2009 and were assessed with follow-up Doppler echocardiography. The impact of balloon to annulus ratio, age, and valve anatomy on the late development of moderate and severe pulmonary valve regurgitation following balloon valvuloplasty was analysed. Results: Six patients (12% had no pulmonary valve regurgitation; 32 (64% had mild, 9 (18% had moderate, and 3 (6% had severe pulmonary valve regurgitation at a mean follow-up of 4 years. Balloon to annulus ratio, age, and valve anatomy were not statistically significant predictors for moderate and severe pulmonary valve regurgitation. Conclusions: The majority of patients in our population had mild pulmonary valve regurgitation. Moderate to severe pulmonary valve regurgitation was well tolerated at midterm follow-up. Age, balloon to annulus ratio, and valve anatomy were not statistically significant predictors for the late development of moderate and severe valve regurgitation. Large and longer follow-up studies are needed to address this question.

  16. Integrating Balloon and Satellite Operation Data Centers for Technology Readiness Assessment

    Science.gov (United States)

    Mattiello-Francisco, Fátima; Fernandes, Jose Oscar

    2016-07-01

    Stratospheric balloon-borne experiments have been one of the most effective ways to validate innovative space technology, taking the advantage of reduced development cycles and low cost in launching and operation. In Brazil, the National Institute for Space Research (INPE) has balloon and satellite ground infrastructures since the 1970´s and the 1990´s, respectively. In the recent past, a strategic approach was adopted on the modernization of balloon ground operation facilities for supporting the protoMIRAX experiment, an X-ray imaging telescope under development at INPE as a pathfinder for the MIRAX (Monitor e Imageador de Raios X) satellite mission. The strategic target was to reuse the SATellite Control System (SATCS), a software framework developed to control and monitor INPÉs satellites, for balloon operation. This paper presents the results of that effort and the new ongoing project, a computer-based framework named I2Bso, which strategic target is to Integrate INPÉs Balloon and Satellite Operation data centers. The I2Bso major purpose is to support the continuous assessment of an innovative technology after different qualification flights either on board balloons or satellites in order to acquire growing evidence for the technology maturity.

  17. Diagnostic and therapeutic direct peroral cholangioscopy using an intraductal anchoring balloon

    Institute of Scientific and Technical Information of China (English)

    Mansour A Parsi; Tyler Stevens; John J Vargo

    2012-01-01

    AIM:To report our experience using a recently introduced anchoring balloon for diagnostic and therapeutic direct peroral cholangioscopy (DPOC).METHODS:Consecutive patients referred for diagnostic or therapeutic peroral cholangioscopy were evaluated in a prospective cohort study.The patients underwent DPOC using an intraductal anchoring balloon,which was recently introduced to allow consistent access to the biliary tree with an ultraslim upper endoscope.The device was later voluntarily withdrawn from the market by the manufacturer.RESULTS:Fourteen patients underwent DPOC using the anchoring balloon.Biliary access with an ultraslim upper endoscope was accomplished in all 14 patients.In 12 (86%) patients,ductal access required sphincteroplasty with a 10-mm dilating balloon.Intraductal placement of the ultraslim upper endoscope allowed satisfactory visualization of the biliary mucosa to the level of the confluence of the right and left hepatic ducts in 13 of 14 patients (93%).Therapeutic interventions by DPOC were successfully completed in all five attempted cases (intraductal biopsy in one and DPOC guided laser lithotripsy in four).Adverse events occurred in a patient on immunosuppressive therapy who developed an intrahepatic biloma at the site of the anchoring balloon.This required hospitalization and antibiotics.Repeat endoscopic retrograde cholangiopancreatography 8 wk after the index procedure showed resolution of the biloma.CONCLUSION:Use of this anchoring balloon allowed consistent access to the biliary tree for performance of diagnostic and therapeutic DPOC distal to the biliary bifurcation.

  18. Correcting the dynamic response of a commercial esophageal balloon-catheter.

    Science.gov (United States)

    Cross, Troy J; Beck, Kenneth C; Johnson, Bruce D

    2016-08-01

    It is generally recommended that an esophageal balloon-catheter possess an adequate frequency response up to 15 Hz, such that parameters of respiratory mechanics may be quantified with precision. In our experience, however, we have observed that some commercially available systems do not display an ideal frequency response (Wiener deconvolution. These two numerical techniques were performed on a commercial balloon-catheter interfaced with 0, 1, and 2 lengths of extension tubing (90 cm each), referred to as configurations L0, L90, and L180, respectively. The frequency response of the balloon-catheter in these configurations was assessed by empirical transfer function analysis, and its "working" range was defined as the frequency beyond which more than 5% amplitude and/or phase distortion was observed. The working frequency range of the uncorrected balloon-catheter extended up to only 10 Hz for L0, and progressively worsened with additional tubing length (L90 = 3 Hz, L180 = 2 Hz). Although both numerical methods of correction adequately enhanced the working frequency range of the balloon-catheter to beyond 25 Hz for all length configurations (L0, L90, and L180), Wiener deconvolution consistently provided more accurate corrections. Our data indicate that Wiener deconvolution provides a superior correction of the balloon-catheter's dynamic response, and is relatively more robust to extensions in catheter tube length compared with the exponential correction method. PMID:27402558

  19. A rectal balloon catheter as internal immobilization device for conformal radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Background: As known from the literature, prostate motion depends on different bladder and/or rectum fillings. The aim of this study was to analyze the influence of a rectum balloon catheter, used as an internal immobilization device, on prostate and rectum motion during the treatment course. Moreover we have analysed if the balloon enables an increase of the distance between the prostate and the posterior rectum wall. Results: An increase of the distance between the prostate and the posterior rectal wall of 8 mm was observed at the base of the prostate when using the rectum balloon. Moreover prostate motion in the ventrodorsal direction ≥4 mm (1 SD) was reduced from 6/10 patients (60%) to 1/10 patients (10%) using the rectal balloon. In general, deviations in the latero-lateral and cranio-caudal directions were less (mean ≤ 2 mm, 1 SD), no difference between both examination series (with and without balloon) was observed. Conclusion: Rectal balloon catheter offers a possibility to reduce prostate motion and rectum filling variations during treatment course. In addition it enables an increase in the distance between prostate and posterior rectal wall, which could enable an improved protection of the posterior rectal wall. (orig./AJ)

  20. Long-Term Outcomes of Balloon Dilation for Acquired Subglottic Stenosis in Children

    Directory of Open Access Journals (Sweden)

    Aliye Filiz

    2014-01-01

    Full Text Available Objectives. Balloon dilation laryngoplasty has been suggested as an alternative treatment to open surgical treatment of acquired subglottic stenosis in children. We describe long-term outcomes of balloon dilation for acquired subglottic stenosis in children. Methods. The medical charts of children who had balloon dilation for subglottic stenosis secondary to intubation were reviewed. Data included demographics, relevant history and physical examination, diagnostic workup, and management. Outcomes of balloon dilation were assessed based on improvement in preoperative symptoms, grading of stenosis, complications, and need for additional procedures. Results. Three children (2 male, 1 female, age range: 14 weeks–1 year underwent balloon dilation for acquired subglottic stenosis. Patients presented with stridor and increased work of breathing. Duration of intubation ranged from 2 days to 3 weeks. Patients became symptomatic 5 days to 6 weeks after extubation. Grade of subglottic stenosis was II in 2 patients and III in one. Subglottic stenosis patients had 2-3 dilations within 2–10 weeks. All patients were asymptomatic during 14–21-month follow-up. Conclusions. Serial balloon dilation was safe and successful method to manage acquired subglottic stenosis in this group of children. No recurrence was noted in a follow-up more than a year after resolution of symptoms.

  1. Long-term outcomes of balloon dilation for acquired subglottic stenosis in children.

    Science.gov (United States)

    Filiz, Aliye; Ulualp, Seckin O

    2014-01-01

    Objectives. Balloon dilation laryngoplasty has been suggested as an alternative treatment to open surgical treatment of acquired subglottic stenosis in children. We describe long-term outcomes of balloon dilation for acquired subglottic stenosis in children. Methods. The medical charts of children who had balloon dilation for subglottic stenosis secondary to intubation were reviewed. Data included demographics, relevant history and physical examination, diagnostic workup, and management. Outcomes of balloon dilation were assessed based on improvement in preoperative symptoms, grading of stenosis, complications, and need for additional procedures. Results. Three children (2 male, 1 female, age range: 14 weeks-1 year) underwent balloon dilation for acquired subglottic stenosis. Patients presented with stridor and increased work of breathing. Duration of intubation ranged from 2 days to 3 weeks. Patients became symptomatic 5 days to 6 weeks after extubation. Grade of subglottic stenosis was II in 2 patients and III in one. Subglottic stenosis patients had 2-3 dilations within 2-10 weeks. All patients were asymptomatic during 14-21-month follow-up. Conclusions. Serial balloon dilation was safe and successful method to manage acquired subglottic stenosis in this group of children. No recurrence was noted in a follow-up more than a year after resolution of symptoms.

  2. Significant skin burns may occur with the use of a water balloon in HIFU treatment

    Science.gov (United States)

    Ritchie, Robert; Collin, Jamie; Wu, Feng; Coussios, Constantin; Leslie, Tom; Cranston, David

    2012-10-01

    HIFU is a minimally-invasive therapy suitable for treating selected intra-abdominal tumors. Treatment is safe although skin burns may occur due to pre-focal heating. HIFU treatment of a renal transplant tumor located in the left lower abdomen was undertaken in our centre. Treatment was performed prone, requiring displacement of the abdominal wall away from the treatment field using a water balloon, constructed of natural rubber latex and filled with degassed water. Intra-operatively, ultrasound imaging and physical examination of the skin directly over the focal region was normal. Immediately post-operative, a full-thickness skin burn was evident at the periphery of the balloon location, outside the expected HIFU path. Three possibilities may account for this complication. Firstly, the water balloon may have acted as a lens, focusing the HIFU to a neo-focus off axis. Secondly, air bubbles may have been entrapped between the balloon and the skin, causing heating at the interface. Finally, heating of the isolated water within the balloon may have been sufficient to cause burning. In this case, the placement of a water balloon caused a significant skin burn. Care should be taken in their use as burns, situated off axis, may occur even if the overlying skin appears normal.

  3. Right ventricular function before and after percutaneous balloon mitral valvuloplasty.

    Science.gov (United States)

    Burger, W; Brinkies, C; Illert, S; Teupe, C; Kneissl, G D; Schräder, R

    1997-01-01

    Aim of this study was to evaluate right ventricular performance in patients with mitral stenosis and its modification by balloon valvuloplasty. Right ventricular volumes of 24 patients with postrheumatic mitral stenosis were determined by thermodilution 1 or 2 days before and 1 or 2 days after valvuloplasty. Right ventricular ejection fraction at rest was 43 (36-47)% (median and interquartile range). Right ventricular end-diastolic volume was 100 (86-119) ml/m2. Supine bicycle exercise (50 Watt) reduced right ventricular ejection fraction to 30 (29-37)% (P volume to 124 (112-141) ml/m2 (P improvement of right ventricular ejection fraction correlated inversely with the value of this parameter before valvuloplasty (r = -0.88, P volume (r = 0.57, P < 0.01). The right ventricular function curve, disturbed before commissurotomy, was reestablished by the procedure. In conclusion, at the here investigated stage of mitral stenosis right ventricular function is reversibly impaired. This is predominantly caused by the hemodynamic consequences of the valvular defect and not by an impairment of right ventricular myocardial function.

  4. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    Science.gov (United States)

    Wlach, S.; Schwarzbauch, M.; Laiacker, M.

    2015-09-01

    The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircrafts. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS). This paper highlights some aspects of the design, building, integration and testing of a flying experimental platform for high altitudes. This unmanned aircraft, with a wingspan of 3 m and a mass of less than 10 kg, is meant to be launched as a glider from a high altitude balloon in 20 km altitude and shall investigate technologies for future large HAPS platforms. The aerodynamic requirements for high altitude flight included the development of a launch method allowing for a safe transition to horizontal flight from free-fall with low control authority. Due to the harsh environmental conditions in the stratosphere, the integration of electronic components in the airframe is a major effort. For regulatory reasons a reliable and situation dependent flight termination system had to be implemented. In May 2015 a flight campaign was conducted. The mission was a full success demonstrating that stratospheric research flights are feasible with rather small aircrafts.

  5. Understanding cosmic rays with Balloon and Space Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Picozza, P., E-mail: piergiorgio.picozza@roma2.infn.it [University of Rome Tor Vergata, Department of Physics, Via della Ricerca Scientifica 1, 00133 Rome (Italy); INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy); Di Felice, V. [INFN, Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2013-10-15

    Measurements of cosmic rays provide important information on their sources and on the mechanisms of acceleration and propagation of cosmic particles through the Galaxy. Positrons and antiprotons in cosmic rays are also the major candidates for searching signals from annihilation of dark matter and contributions from other exotic sources as nearby pulsars. Many balloon-borne experiments have been performed since the sixties, obtaining important results that strongly suggested the realization of the PAMELA and Fermi satellite missions, the latter mainly for gamma rays, and AMS-02 on the ISS. The precision of the measurements and the high statistics highlighted unexpected features in the cosmic particle energy spectra that are setting strong constraints to the nature of Dark Matter and are contributing to change our basic vision of their origin and propagation. The continuous particle detection in space experiments is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms.

  6. Balloon catheter dilatation for mitral stenosis and severe pulmonary hypertension

    International Nuclear Information System (INIS)

    Objective: To determine the safety and efficacy of percutaneous balloon mitral valvuloplasty (PBMV) for patients with mitral stenosis and severe pulmonary hypertension, and to assess the changes in pulmonary systolic pressure during follow-up. Methods: Forty-two patients with rheumatic mitral stenosis and severe pulmonary hypertension (pulmonary systolic pressure > 75 mmHg) underwent PBMV using standard Inoue technique, and the changes in clinical functional status and echo Doppler pulmonary systolic pressure during follow-up were assessed. Results: PBMV was successful in 39 patients. Immediately after the procedure, mitral valve area increased from (0.83 +- 0.12) cm2 to (1.75 +- 0.11) cm2, pulmonary systolic pressure decreased from (85 +- 7) mmHg to (61 +- 13) mmHg (all P < 0.001). Severe mitral regurgitation occurred in 3 patients, one of whom underwent mitral valve replacement. During follow-up (average 6 months), in 39 patients with successful PBMV, the clinical functional status was improved and pulmonary systolic pressure was further decreased despite unchanged mitral valve area. Conclusions: PBMV was safe and effective for patients with mitral stenosis and severe pulmonary hypertension. Clinical functional status was improved and pulmonary systolic pressure was continuously decreased during the short-term follow-up

  7. EBEX: A balloon-borne CMB polarization experiment

    CERN Document Server

    Reichborn-Kjennerud, Britt; Ade, Peter; Aubin, Françcois; Baccigalupi, Carlo; Bao, Chaoyun; Borrill, Julian; Cantalupo, Christopher; Chapman, Daniel; Didier, Joy; Dobbs, Matt; Grain, Julien; Grainger, William; Hanany, Shaul; Hillbrand, Seth; Hubmayr, Johannes; Jaffe, Andrew; Johnson, Bradley; Jones, Terry; Kisner, Theodore; Klein, Jeff; Korotkov, Andrei; Leach, Sam; Lee, Adrian; Levinson, Lorne; Limon, Michele; MacDermid, Kevin; Matsumura, Tomotake; Meng, Xiaofan; Miller, Amber; Milligan, Michael; Pascale, Enzo; Polsgrove, Daniel; Ponthieu, Nicolas; Raach, Kate; Sagiv, Ilan; Smecher, Graeme; Stivoli, Federico; Stompor, Radek; Tran, Huan; Tristram, Matthieu; Tucker, Gregory S; Vinokurov, Yury; Yadav, Amit; Zaldarriaga, Matias; Zilic, Kyle

    2010-01-01

    EBEX is a NASA-funded balloon-borne experiment designed to measure the polarization of the cosmic microwave background (CMB). Observations will be made using 1432 transition edge sensor (TES) bolometric detectors read out with frequency multiplexed SQuIDs. EBEX will observe in three frequency bands centered at 150, 250, and 410 GHz, with 768, 384, and 280 detectors in each band, respectively. This broad frequency coverage is designed to provide valuable information about polarized foreground signals from dust. The polarized sky signals will be modulated with an achromatic half wave plate (AHWP) rotating on a superconducting magnetic bearing (SMB) and analyzed with a fixed wire grid polarizer. EBEX will observe a patch covering ~1% of the sky with 8' resolution, allowing for observation of the angular power spectrum from \\ell = 20 to 1000. This will allow EBEX to search for both the primordial B-mode signal predicted by inflation and the anticipated lensing B-mode signal. Calculations to predict EBEX constrain...

  8. Pointing control for the SPIDER balloon-borne telescope

    CERN Document Server

    Shariff, Jamil A; Amiri, Mandana; Benton, Steven J; Bock, Jamie J; Bond, J Richard; Bryan, Sean A; Chiang, H Cynthia; Contaldi, Carlo R; Crill, Brendan P; Doré, Olivier P; Farhang, Marzieh; Filippini, Jeffrey P; Fissel, Laura M; Fraisse, Aurelien A; Gambrel, Anne E; Gandilo, Natalie N; Golwala, Sunil R; Gudmundsson, Jon E; Halpern, Mark; Hasselfield, Matthew; Hilton, Gene C; Holmes, Warren A; Hristov, Viktor V; Irwin, Kent D; Jones, William C; Kermish, Zigmund D; Kuo, Chao-Lin; MacTavish, Carolyn J; Mason, Peter V; Megerian, Krikor G; Moncelsi, Lorenzo; Morford, Tracy A; Nagy, Johanna M; Netterfield, C Barth; O'Brient, Roger; Rahlin, Alexandra S; Reintsema, Carl D; Ruhl, John E; Runyan, Marcus C; Soler, Juan D; Trangsrud, Amy; Tucker, Carole E; Tucker, Rebecca S; Turner, Anthony D; Weber, Alexis C; Wiebe, Donald V; Young, Edward Y

    2014-01-01

    We present the technology and control methods developed for the pointing system of the SPIDER experiment. SPIDER is a balloon-borne polarimeter designed to detect the imprint of primordial gravitational waves in the polarization of the Cosmic Microwave Background radiation. We describe the two main components of the telescope's azimuth drive: the reaction wheel and the motorized pivot. A 13 kHz PI control loop runs on a digital signal processor, with feedback from fibre optic rate gyroscopes. This system can control azimuthal speed with < 0.02 deg/s RMS error. To control elevation, SPIDER uses stepper-motor-driven linear actuators to rotate the cryostat, which houses the optical instruments, relative to the outer frame. With the velocity in each axis controlled in this way, higher-level control loops on the onboard flight computers can implement the pointing and scanning observation modes required for the experiment. We have accomplished the non-trivial task of scanning a 5000 lb payload sinusoidally in az...

  9. Novel Balloon Surface Scanning Device for Intraoperative Breast Endomicroscopy.

    Science.gov (United States)

    Zuo, Siyang; Hughes, Michael; Yang, Guang-Zhong

    2016-07-01

    Recent advances in fluorescence confocal endomicroscopy have allowed real-time identification of residual tumour cells on the walls of the cavity left by breast conserving surgery. However, it is difficult to systematically survey the surgical site because of the small imaging field-of-view of these probes, compounded by tissue deformation and inconsistent probe-tissue contact when operated manually. Therefore, a new robotized scanning device is required for controlled, large area scanning and mosaicing. This paper presents a robotic scanning probe with an inflatable balloon, providing stable cavity scanning over undulating surfaces. It has a compact design, with an outer diameter of 4 mm and a working channel of 2.2 mm, suitable for a leached flexible fibre bundle endomicroscope probe. With the probe inserted, the tip positioning accuracy measured to be 0.26 mm for bending and 0.17 mm for rotational motions. Large area scanning was achieved (25-35 mm(2)) and the experimental results demonstrate the potential clinical value of the device for intraoperative cavity tumour margin evaluation. PMID:26508330

  10. The Balloon-borne Large Aperture Submillimeter Telescope: BLAST

    CERN Document Server

    Pascale, E; Bock, J J; Chapin, E L; Chung, J; Devlin, M J; Dicker, S; Griffin, M; Gundersen, J O; Halpern, M; Hargrave, P C; Hughes, D H; Klein, J; MacTavish, C J; Marsden, G; Martin, P G; Martin, T G; Mauskopf, P; Netterfield, C B; Olmi, L; Patanchon, G; Rex, M; Scott, D; Semisch, C; Thomas, N; Truch, M D P; Tucker, C; Tucker, G S; Viero, M P; Wiebe, D V

    2007-01-01

    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a sub-orbital survey-experiment designed to study the evolutionary history and processes of star formation in local galaxies (including the Milky Way) and galaxies at cosmological distances. The BLAST continuum camera, which consists of 270 detectors distributed between 3 arrays, observes simultaneously in broad-band (30%) spectral-windows at 250, 350, and 500 micron. The optical design is based on a 2m diameter Cassegrain telescope, providing a diffraction-limited resolution of 30" at 250 micron. The gondola pointing system enables raster-like maps of arbitrary geometry, with a repeatable positional accuracy of ~30" post-flight pointing reconstruction to ~<5" rms is also achieved. The on-board telescope control software permits autonomous execution of a pre-selected set of maps, with the option of manual intervention. In this paper we describe the primary characteristics and measured in-flight performance of BLAST. Since a test-flight in ...

  11. Kinetic analysis of MHD ballooning modes in tokamaks

    International Nuclear Information System (INIS)

    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

  12. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius

    2013-01-01

    Masonry cavity walls are loaded by wind pressure and vertical load from upper floors. These loads results in bending moments and compression forces in the ties connecting the outer and the inner wall in a cavity wall. Large cavity walls are furthermore loaded by differential movements from...... the temperature gradient between the outer and the inner wall, which results in critical increase of the bending moments in the ties. Since the ties are loaded by combined compression and moment forces, the loadbearing capacity is derived from instability equilibrium equations. Most of them are iterative, since...

  13. The instability of Wilton ripples

    CERN Document Server

    Trichtchenko, Olga; Wilkening, Jon

    2015-01-01

    Wilton ripples are a type of periodic traveling wave solution of the full water wave problem incorporating the effects of surface tension. They are characterized by a resonance phenomenon that alters the order at which the resonant harmonic mode enters in a perturbation expansion. We compute such solutions using non-perturbative numerical methods and investigate their stability by examining the spectrum of the water wave problem linearized about the resonant traveling wave. Instabilities are observed that differ from any previously found in the context of the water wave problem.

  14. High Altitude Balloons as a Platform for Space Radiation Belt Science

    Science.gov (United States)

    Mazzino, L.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Johnson, W.; Mann, I. R.; Rae, J.; University of Alberta High Altitude Balloons (UA-HAB)

    2011-12-01

    The goals of the University of Alberta High Altitude Balloons Program (UA-HAB) are to i) use low cost balloons to address space radiation science, and ii) to utilise the excitement of "space mission" involvement to promote and facilitate the recruitment of undergraduate and graduate students in physics, engineering, and atmospheric sciences to pursue careers in space science and engineering. The University of Alberta High Altitude Balloons (UA-HAB) is a unique opportunity for University of Alberta students (undergraduate and graduate) to engage in the hands-on design, development, build, test and flight of a payload to operate on a high altitude balloon at around 30km altitude. The program development, including formal design and acceptance tests, reports and reviews, mirror those required in the development of an orbital satellite mission. This enables the students to gain a unique insight into how space missions are flown. UA-HAB is a one and half year program that offers a gateway into a high-altitude balloon mission through hands on experience, and builds skills for students who may be attracted to participate in future space missions in their careers. This early education will provide students with the experience necessary to better assess opportunities for pursuing a career in space science. Balloons offer a low-cost alternative to other suborbital platforms which can be used to address radiation belt science goals. In particular, the participants of this program have written grant proposal to secure funds for this project, have launched several 'weather balloon missions', and have designed, built, tested, and launched their particle detector called "Maple Leaf Particle Detector". This detector was focussed on monitoring cosmic rays and space radiation using shielded Geiger tubes, and was flown as one of the payloads from the institutions participating in the High Altitude Student Platform (HASP), organized by the Louisiana State University and the Louisiana

  15. Mode-locking via dissipative Faraday instability.

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-01-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering. PMID:27503708

  16. Transverse Instabilities in the Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L.R.; Burov, A.; Shemyakin, A.; Bhat, C.M.; Crisp, J.; Eddy, N.; /Fermilab

    2011-07-01

    Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly lowered for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.

  17. Mode-locking via dissipative Faraday instability

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M.; Churkin, Dmitry V.; Staliunas, Kestutis; Turitsyn, Sergei K.

    2016-08-01

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system--spectrally dependent losses--achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  18. Radiation induced chromosome instability in human fibroblasts

    International Nuclear Information System (INIS)

    Evidence has been arising that some biological effects can manifest many cell divisions after irradiation. We have demonstrated that de novo chromosome instability can be detected 10- 15 mean population doubling after heavy ion irradiations. This chromosome instability is characterized by end to end fusions between specific chromosomes. The specificity of the instability may differ from one donor to another but for the same donor, the same instability should be observed after irradiation, during the senescence process and after SV40 transfection (before crisis). In irradiated primary culture fibroblasts, the expression of the delayed chromosomal instability lasts for several cell divisions without inducing cell death. Several rounds of fusions- breakage-fusions can be performed and unbalanced clones emerge (gain or loss of chromosomes with the shorter telomeres would become unstable first.. The difference in the chromosomal instability among donors could be due to a polymorphism in telomere lengths. This could induce large variation in long term response to irradiation among individuals. (author)

  19. Optimal excitation of two dimensional Holmboe instabilities

    CERN Document Server

    Constantinou, Navid C

    2010-01-01

    Highly stratified shear layers are rendered unstable even at high stratifications by Holmboe instabilities when the density stratification is concentrated in a small region of the shear layer. These instabilities may cause mixing in highly stratified environments. However these instabilities occur in tongues for a limited range of parameters. We perform Generalized Stability analysis of the two dimensional perturbation dynamics of an inviscid Boussinesq stratified shear layer and show that Holmboe instabilities at high Richardson numbers can be excited by their adjoints at amplitudes that are orders of magnitude larger than by introducing initially the unstable mode itself. We also determine the optimal growth that obtains for parameters for which there is no instability. We find that there is potential for large transient growth regardless of whether the background flow is exponentially stable or not and that the characteristic structure of the Holmboe instability asymptotically emerges for parameter values ...

  20. Material and structural instabilities of single-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    J. Wu; K. C. Hwang; J. Song; Y. Huang

    2008-01-01

    The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the structural instability. We use the finite-deformation shell theory based on the interatomic potential to show that the tension instability of single-wall carbon nanotubes is the material instability, while the compression and torsion instabilities are structural instability.

  1. Instabilities and transition in boundary layers

    Indian Academy of Sciences (India)

    N Vinod; Rama Govindarajan

    2005-03-01

    Some recent developments in boundary layer instabilities and transition are reviewed. Background disturbance levels determine the instability mechanism that ultimately leads to turbulence. At low noise levels, the traditional Tollmien–Schlichting route is followed, while at high levels, a `by-pass' route is more likely. Our recent work shows that spot birth is related to the pattern of secondary instability in either route.

  2. Instability of SmS under pressure

    International Nuclear Information System (INIS)

    It is suggested that electron-phonon (EP) interaction is a suitable mechanism to explain the instability of the semiconducting phase in SmS under pressure. The f reversible d and d reversible d scattering processes due to EP interaction avoid the introduction of negative renormalized f-d hybridization assumed by some other models as the source of the first order instability. Moreover this instability is shown as occuring for a non-zero energy gap. (orig.)

  3. Beam Instabilities in the Scale Free Regime

    CERN Document Server

    Folli, Viola; Conti, Claudio; 10.1103/PhysRevLett.108.033901

    2012-01-01

    The instabilities arising in a one-dimensional beam sustained by the diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are theoretically and numerically investigated. In the "scale-free model", in striking contrast with the well-known spatial modulational instability, two different beam instabilities dominate: a defocusing and a fragmenting process. Both are independent of the beam power and are not associated to any specific periodic pattern.

  4. Electron proton instability in the CSNS ring

    Institute of Scientific and Technical Information of China (English)

    WANG Na; QIN Qing; LIU Yu-Dong

    2009-01-01

    The electron proton(e-p)instability has been observed in many proton accelerators.It will induce transverse beam size blow-up,cause beam loss and restrict the machine performance.Much research work has been done on the causes,dynamics and cures of this instability.A simulation code is developed to study the e-p instability in the ring of the China Spallation Neutron Source(CSNS).

  5. Cultural diversity, economic development and societal instability

    OpenAIRE

    Daniel Nettle; Grace, James B.; Marc Choisy; Howard V Cornell; Jean-François Guégan; Michael E Hochberg

    2007-01-01

    BACKGROUND: Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation or alpha diversity, but also diversity between a nation and its neighbours or beta diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are media...

  6. Kelvin-Helmholtz instabilities with Godunov SPH

    OpenAIRE

    Cha, Seung-Hoon; Inutsuka, Shu-Ichiro; Nayakshin, Sergei

    2009-01-01

    Numerical simulations for the non-linear development of Kelvin-Helmholtz instability in two different density layers have been performed with the particle-based method (Godunov SPH) developed by Inutsuka (2002). The Godunov SPH can describe the Kelvin-Helmholtz instability even with a high density contrast, while the standard SPH shows the absence of the instability across a density gradient (Agertz et al. 2007). The interaction of a dense blob with a hot ambient medium has been performed als...

  7. Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles

    OpenAIRE

    Dorf, M.; H. Bösch; Butz, A.; Camy-Peyret, C.; Chipperfield, M. P.; Engel, A.; Goutail, F.; Grunow, K.; Hendrick, F.; Hrechanyy, S.; B. Naujokat; J.-P. Pommereau; Van Roozendael, M.; C. Sioris; F. Stroh

    2006-01-01

    For the first time, results of four stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-borne in situ ...

  8. Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles

    OpenAIRE

    Dorf, M.; H. Bösch; Butz, A.; Camy-Peyret, C.; Chipperfield, M. P.; Engel, A.; Goutail, F.; Grunow, K.; Hendrick, F.; Hrechanyy, S.; B. Naujokat; J.-P. Pommereau; Van Roozendael, M.; C. Sioris; F. Stroh

    2005-01-01

    For the first time, results of all four existing stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-b...

  9. Balloon-borne stratospheric BrO measurements : comparison with Envisat/SCIAMACHY BrO limb profiles

    OpenAIRE

    Dorf, Marcel; Bösch, Hartmut; BUTZ Andre; Camy-Peyret, Claude C.; Chipperfield, Martyn P.; Engel, Andreas; Goutail, Florence; Grunow, Katja; Hendrick, François; Hrechanyy, Serhiy; Naujokat, Barbara; Pommereau, Jean-Pierre; Van Roozendael, Michel; Sioris, Christopher E.; Stroh, Fred

    2005-01-01

    For the first time, results of all four existing stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-b...

  10. Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles

    OpenAIRE

    Dorf, Marcel; Bösch, Hartmut; BUTZ Andre; Camy-Peyret, Claude C.; Chipperfield, Martyn P.; Engel, Andreas; Goutail, Florence; Grunow, Katja; Hendrick, François; Hrechanyy, Serhiy; Naujokat, Barbara; Pommereau, Jean-Pierre; Van Roozendael, Michel; Sioris, Christopher E.; Stroh, Fred

    2006-01-01

    For the first time, results of all four existing stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-b...

  11. Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles

    OpenAIRE

    Dorf, M.; H. Bösch; B. Naujokat; Pommereau, J. P.; Van Roozendael, M.; C. Sioris; F. Stroh; Weidner, F.; K. Pfeilsticker; Butz, A.; Camy-Peyret, C.; Chipperfield, M. P.; Engel, A.; Goutail, F.; Grunow, K.

    2006-01-01

    For the first time, results of four stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include ( a) balloon-borne in situ...

  12. Aeroelastic instability problems for wind turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2007-01-01

    This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical...... stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research...... issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd....

  13. Size-effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur. If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavity...... triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays...

  14. Review of two-phase instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Han Ok; Seo, Han Ok; Kang, Hyung Suk; Cho, Bong Hyun; Lee, Doo Jeong

    1997-06-01

    KAERI is carrying out a development of the design for a new type of integral reactors. The once-through helical steam generator is important design features. The study on designs and operating conditions which prevent flow instability should precede the introduction of one-through steam generator. Experiments are currently scheduled to understand two-phase instability, evaluate the effect of each design parameter on the critical point, and determine proper inlet throttling for the prevention of instability. This report covers general two-phase instability with review of existing studies on this topics. The general classification of two phase flow instability and the characteristics of each type of instability are first described. Special attention is paid to BWR core flow instability and once-through steam generator instability. The reactivity feedback and the effect of system parameters are treated mainly for BWR. With relation to once-through steam generators, the characteristics of convective heating and dryout point oscillation are first investigated and then the existing experimental studies are summarized. Finally chapter summarized the proposed correlations for instability boundary conditions. (author). 231 refs., 5 tabs., 47 figs

  15. Early Prevention Method for Power Systems Instability

    DEFF Research Database (Denmark)

    Dmitrova, Evgenia

    In the scope of this work, a method capable of fast identification of the proper countermeasure, that prevents emerging instability, has been developed. The focus is placed on the prevention of aperiodic small signal angular instability by means of manipulations applied to load nodes (nodes...... instability was created. Utilizing synthetic PMU data, the early prevention method proposed a location and an amount of the countermeasure which will prevent instability; the prediction of the resulting stability margins corresponding to application of the suggested countermeasure was carried out...

  16. Instabilities of flows and transition to turbulence

    CERN Document Server

    Sengupta, Tapan K

    2012-01-01

    Introduction to Instability and TransitionIntroductionWhat Is Instability?Temporal and Spatial InstabilitySome Instability MechanismsComputing Transitional and Turbulent FlowsFluid Dynamical EquationsSome Equilibrium Solutions of the Basic EquationBoundary Layer TheoryControl Volume Analysis of Boundary LayersNumerical Solution of the Thin Shear Layer (TSL) EquationLaminar Mixing LayerPlane Laminar JetIssues of Computing Space-Time Dependent FlowsWave Interaction: Group Velocity and Energy FluxIssues of Space-Time Scale Resolution of FlowsTemporal Scales in Turbulent FlowsComputing Time-Averag

  17. Hydrodynamic instabilities and neutron scattering

    International Nuclear Information System (INIS)

    The flow pattern in a liquid layer heated from below changes character as the vertical temperature gradient is increased. A review is given for the sequence of instabilities connected with the different flow regimes, with emphasis on their phase-transition aspects. Utilizing the coupling that exists between the molecular orientation and flow in a liquid crystal, we have used neutron scattering to explore these phenomena. The special features of liquid crystals in this respect are pointed out. Experiments near the lowest lying instability, the Rayleigh-Benard transition, verify the mean-field predictions for the change of the threshold gradient with the applied magnetic field, the behaviour of the order parameter (the fluid velocity) versus epsilon (the reduced gradient scale), the time-dependent growth and the critical slowing down of the growth rate of the order parameter. A pre-transitional tail of intensity is analysed within the same formalism and it is suggested that it arises from hydrodynamic fluctuations driven by the microscopic fluctuations of the liquid. Experiments at higher gradients reveal a time-periodic flow regime with frequencies down to cycles per hour. These observations lend support to modern theories for the transition to turbulence. (author)

  18. Combustion instability modeling and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1995-10-01

    It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.

  19. Instability of a penetrating blade

    Science.gov (United States)

    Bigoni, D.; Bosi, F.; Dal Corso, F.; Misseroni, D.

    2014-03-01

    Application of a dead compressive load at the free end of an elastic rod (the ‘blade') induces its penetration into a sliding sleeve ending with a linear elastic spring. Bifurcation and stability analysis of this simple elastic system shows a variety of unexpected behaviors: (i) an increase of buckling load at decreasing of elastic stiffness; (ii) a finite number of buckling loads for a system with infinite degrees of freedom (leading to a non-standard Sturm-Liouville problem); (iii) more than one bifurcation load associated to each bifurcation mode; (iv) a restabilization of the straight configuration after the second bifurcation load associated to the first instability mode; (v) the presence of an Eshelby-like (or configurational) force, deeply influencing stability. Only the first of these behaviors was previously known, the second and third ones disprove common beliefs, the fourth highlights a sort of ‘island of instability', and the last one shows surprising phenomena and effects on stability.

  20. Rogue Waves and Modulational Instability

    Science.gov (United States)

    Zakharov, V. E.; Dyachenko, A.

    2015-12-01

    The most plausible cause of rogue wave formation in a deep ocean is development of modulational instability of quasimonochromatic wave trains. An adequate model for study of this phenomenon is the Euler equation for potential flow of incompressible fluid with free surface in 2-D geometry. Numerical integration of these equations confirms completely the conjecture of rogue wave formation from modulational instability but the procedure is time consuming for determination of rogue wave appearance probability for a given shape of wave energy spectrum. This program can be realized in framework of simpler model using replacement of the exact interaction Hamiltonian by more compact Hamiltonian. There is a family of such models. The popular one is the Nonlinear Schrodinger equation (NLSE). This model is completely integrable and suitable for numerical simulation but we consider that it is oversimplified. It misses such important phenomenon as wave breaking. Recently, we elaborated much more reliable model that describes wave breaking but is as suitable as NLSE from the point of numerical modeling. This model allows to perform massive numerical experiments and study statistics of rogue wave formation in details.

  1. Recent Results and Near Term Outlook for the NASA Balloon Science Program

    Science.gov (United States)

    Jones, William Vernon

    Long-duration and conventional balloon flights in the traditional Astrophysics, Solar and Heliophysics, and Earth Science disciplines have continued in both polar and non-polar regions since the 39th COSPAR Assembly in Mysore, India. One of these established a new flight record of 55 days over Antarctica during the 2012-2013 austral season. That Super-TIGER science flight broke both the 42-day record of the CREAM science flight during the 2004-2005 season and the 54-day super pressure balloon test flight in 2008-2009. With two comets approaching the sun in 2013-2014, the Planetary Science community has shown increased interest in remote observations of comets, planets, and other objects in the Solar System. All of the above science disciplines are interested in super pressure balloon (SPB) flights, which have been under development by NASA, and which were strongly supported by the Astro2010 Decadal Study. A 532,152 m3 (18.8 MCF) SPB with a major gamma ray astrophysics payload is planned for an ultra-long duration balloon (ULDB) test flight around and from Antarctica during the upcoming 2014-2015 season. Flights for SPB qualification to support 1000 kg science instruments to 33 km altitude have proceeded in parallel with planning for options to increase the altitude for less massive instruments that require less atmospheric overburden. The nearly constant SPB volume will provide stable altitude long-duration flights at non-polar latitudes, thereby supporting a much broader range of scientific investigations. Scientific ballooning continues to complement and enable space missions, while training young scientists and systems engineers for the workforce needed to conduct future missions. Highlights of results from past balloon-borne measurements and expected results from ongoing and planned balloon-borne experiments will be presented.

  2. Application of new balloon catheters in the treatment of congenital heart defects

    Science.gov (United States)

    Fiszer, Roland; Szkutnik, Małgorzata; Smerdziński, Sebastian; Chodór, Beata; Białkowski, Jacek

    2016-01-01

    Introduction Balloon angioplasty (BAP) and aortic or pulmonary balloon valvuloplasty (BAV, BPV) are well-established treatment options in congenital heart defects. Recently, significant technological progress has been made and new catheters have been implemented in clinical practice. Aim To analyze the results of BAP, BAV and BPV with the new balloon catheter Valver and its second generation Valver II, which the company Balton (Poland) launched and developed. These catheters have not been clinically evaluated yet. Material and methods We performed 64 interventions with Valver I and Valver II. With Valver I the following procedures were performed: 17 BPV (including 9 in tetralogy of Fallot – TOF), 10 BAV and 27 BAP in coarctations of the aorta (CoA) – including 9 native and 18 after surgery. With Valver II ten interventions were done – 3 BPV, 2 pulmonary supravalvular BAP (after switch operations), 2 BAP of recoarctations and 3 other BAP. Age of the patients ranged from a few days to 40 years. Results All procedures were completed successfully, without rupture of any balloon catheters. The pressure gradient drop was statistically significant in all groups: BPV in isolated pulmonary valvular stenosis 28.1 mm Hg (mean), BPV in TOF 18.7 mm Hg, BAV 32.8 mm Hg, BAP in native CoA 15.4 mm Hg and in recoarctations 18.6 mm Hg. In 3 cases during rapid deflation of Valver I, wrinkles of the balloons made it impossible to insert the whole balloon into the vascular sheath (all were removed surgically from the groin). No such complication occured with Valver II. Conclusions Valver balloon catheters are an effective treatment modality in different valvular and vascular stenoses. PMID:27625686

  3. Implementation of a Novel Flight Tracking and Recovery Package for High Altitude Ballooning Missions

    Science.gov (United States)

    Fatima, Aqsa; Nekkanti, Sanjay; Mohan Suri, Ram; Shankar, Divya; Prasad Nagendra, Narayan

    High altitude ballooning is typically used for scientific missions including stratospheric observations, aerological observations, and near space environment technology demonstration. The usage of stratospheric balloons is a cost effective method to pursue several scientific and technological avenues against using satellites in the void of space. Based on the Indian Institute of Astrophysics (IIA) ballooning program for studying Comet ISON using high altitude ballooning, a cost effective flight tracking and recovery package for ballooning missions has been developed using open source hardware. The flight tracking and recovery package is based on using Automatic Packet Reporting System (APRS) and has a redundant Global System for Mobile Communications (GSM) based Global Positioning System (GPS) tracker. The APRS based tracker uses AX.25 protocol for transmission of the GPS coordinates (latitude, longitude, altitude, time) alongside the heading and health parameters of the board (voltage, temperature). APRS uses amateur radio frequencies where data is transmitted in packet messaging format, modulated by radio signals. The receiver uses Very High Frequency (VHF) transceiver to demodulate the APRS signals. The data received will be decoded using MixW (open source software). A bridge will be established between the decoding software and the APRS software. The flight path will be predicted before the launch and the real time position co-ordinates will be used to obtain the real time flight path that will be uploaded online using the bridge connection. We also use open source APRS software to decode and Google Earth to display the real time flight path. Several ballooning campaigns do not employ payload data transmission in real time, which makes the flight tracking and package recovery vital for data collection and recovery of flight instruments. The flight tracking and recovery package implemented in our missions allow independent development of the payload package

  4. Beta-limiting Instabilities and Global Mode Stabilization in NSTX

    Science.gov (United States)

    Sabbagh, Steven

    2001-10-01

    Low aspect ratio and high edge q theoretically alter the plasma stability and mode structure compared to standard tokamak configurations. Below the no-wall limit, stability calculations with PEST, GATO, and DCON show the perturbed radial field is maximized near the center column and DCON and VALEN calculations show that mode stability is not greatly improved by a nearby conducting wall due to the short poloidal wavelength in this region. In contrast, as beta reaches and exceeds the no-wall limit, the mode becomes strongly ballooning with long poloidal wavelength at large major radius and is highly wall stabilized. In this way, wall stabilization is more effective at higher beta in low aspect ratio geometry. Research on the stability of spherical torus plasmas at and above the no-wall beta limit is being addressed on NSTX, which has produced low aspect ratio plasmas, R/a = 1.27 at plasma current up to 1.4 MA with high energy confinement (TauE/TauE-ITER89P = 2). Toroidal and normalized beta have reached 22%, and 4.3, respectively in q = 7 plasmas. The beta limit is observed to increase with increasing plasma internal inductance, li, and the stability factor betaN/li has reached 5.8, limited by sudden beta collapses at low li that was achieved by use of high-harmonic fast wave heating (HHFW). DCON stability analysis of equilibria reconstructed with EFIT using external magnetics show that the plasmas are below or at the no-wall beta limit for the n = 1 mode, which has characteristics of a current-driven kink. With more peaked current profiles (li greater than 0.7), core MHD instabilities are observed which saturate or slowly degrade beta. Sawteeth with large inversion radii can also cause substantial beta collapses, although current profile modification using HHFW, altered plasma growth, and increased toroidal field have each been successful in mitigating this effect.

  5. Sodium ferulate inhibits neointimal hyperplasia in rat balloon injury model.

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    Full Text Available BACKGROUND/AIM: Neointimal formation after vessel injury is a complex process involving multiple cellular and molecular processes. Inhibition of intimal hyperplasia plays an important role in preventing proliferative vascular diseases, such as restenosis. In this study, we intended to identify whether sodium ferulate could inhibit neointimal formation and further explore potential mechanisms involved. METHODS: Cultured vascular smooth muscle cells (VSMCs isolated from rat thoracic aorta were pre-treated with 200 µmol/L sodium ferulate for 1 hour and then stimulated with 1 µmol/L angiotensin II (Ang II for 1 hour or 10% serum for 48 hours. Male Sprague-Dawley rats subjected to balloon catheter insertion were administrated with 200 mg/kg sodium ferulate (or saline for 7 days before sacrificed. RESULTS: In presence of sodium ferulate, VSMCs exhibited decreased proliferation and migration, suppressed intracellular reactive oxidative species production and NADPH oxidase activity, increased SOD activation and down-regulated p38 phosphorylation compared to Ang II-stimulated alone. Meanwhile, VSMCs treated with sodium ferulate showed significantly increased protein expression of smooth muscle α-actin and smooth muscle myosin heavy chain protein. The components of Notch pathway, including nuclear Notch-1 protein, Jagged-1, Hey-1 and Hey-2 mRNA, as well as total β-catenin protein and Cyclin D1 mRNA of Wnt signaling, were all significantly decreased by sodium ferulate in cells under serum stimulation. The levels of serum 8-iso-PGF2α and arterial collagen formation in vessel wall were decreased, while the expression of contractile markers was increased in sodium ferulate treated rats. A decline of neointimal area, as well as lower ratio of intimal to medial area was observed in sodium ferulate group. CONCLUSION: Sodium ferulate attenuated neointimal hyperplasia through suppressing oxidative stress and phenotypic switching of VSMCs.

  6. Material Properties Analysis of Structural Members in Pumpkin Balloons

    Science.gov (United States)

    Sterling, W. J.

    2003-01-01

    The efficient design, service-life qualification, and reliability predictions for lightweight aerospace structures require careful mechanical properties analysis of candidate structural materials. The demand for high-quality laboratory data is particularly acute when the candidate material or the structural design has little history. The pumpkin-shaped super-pressure balloon presents both challenges. Its design utilizes load members (tendons) extending from apex to base around the gas envelope to achieve a lightweight structure. The candidate tendon material is highly weight-efficient braided HM cord. Previous mechanical properties studies of Zylon have focused on fiber and yarn, and industrial use of the material in tensile applications is limited. For high-performance polymers, a carefully plamed and executed properties analysis scheme is required to ensure the data are relevant to the desired application. Because no directly-applicable testing standard was available, a protocol was developed based on guidelines fiom professional and industry organizations. Due to the liquid-crystalline nature of the polymer, the cord is very stiff, creeps very little, and does not yield. Therefore, the key material property for this application is the breaking strength. The pretension load and gauge length were found to have negligible effect on the measured breaking strength over the ranges investigated. Strain rate was found to have no effect on breaking strength, within the range of rates suggested by the standards organizations. However, at the lower rate more similar to ULDB operations, the strength was reduced. The breaking strength increased when the experiment temperature was decreased from ambient to 183K which is the lowest temperature ULDB is expected to experience. The measured strength under all test conditions was well below that resulting from direct scale-up of fiber strength based on the manufacturers data. This expected result is due to the effects of the

  7. Modeling the ascent of sounding balloons: derivation of the vertical air motion

    Directory of Open Access Journals (Sweden)

    A. Gallice

    2011-10-01

    Full Text Available A new model to describe the ascent of sounding balloons in the troposphere and lower stratosphere (up to ∼30–35 km altitude is presented. Contrary to previous models, detailed account is taken of both the variation of the drag coefficient with altitude and the heat imbalance between the balloon and the atmosphere. To compensate for the lack of data on the drag coefficient of sounding balloons, a reference curve for the relationship between drag coefficient and Reynolds number is derived from a dataset of flights launched during the Lindenberg Upper Air Methods Intercomparisons (LUAMI campaign. The transfer of heat from the surrounding air into the balloon is accounted for by solving the radial heat diffusion equation inside the balloon. In its present state, the model does not account for solar radiation, i.e. it is only able to describe the ascent of balloons during the night. It could however be adapted to also represent daytime soundings, with solar radiation modeled as a diffusive process. The potential applications of the model include the forecast of the trajectory of sounding balloons, which can be used to increase the accuracy of the match technique, and the derivation of the air vertical velocity. The latter is obtained by subtracting the ascent rate of the balloon in still air calculated by the model from the actual ascent rate. This technique is shown to provide an approximation for the vertical air motion with an uncertainty error of 0.5 m s−1 in the troposphere and 0.2 m s−1 in the stratosphere. An example of extraction of the air vertical velocity is provided in this paper. We show that the air vertical velocities derived from the balloon soundings in this paper are in general agreement with small-scale atmospheric velocity fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions measured during the SUCCESS campaign (Subsonic Aircraft: Contrail and Cloud Effects

  8. Interfacial instabilities in vibrated fluids

    Science.gov (United States)

    Porter, Jeff; Laverón-Simavilla, Ana; Tinao Perez-Miravete, Ignacio; Fernandez Fraile, Jose Javier

    2016-07-01

    Vibrations induce a range of different interfacial phenomena in fluid systems depending on the frequency and orientation of the forcing. With gravity, (large) interfaces are approximately flat and there is a qualitative difference between vertical and horizontal forcing. Sufficient vertical forcing produces subharmonic standing waves (Faraday waves) that extend over the whole interface. Horizontal forcing can excite both localized and extended interfacial phenomena. The vibrating solid boundaries act as wavemakers to excite traveling waves (or sloshing modes at low frequencies) but they also drive evanescent bulk modes whose oscillatory pressure gradient can parametrically excite subharmonic surface waves like cross-waves. Depending on the magnitude of the damping and the aspect ratio of the container, these locally generated surfaces waves may interact in the interior resulting in temporal modulation and other complex dynamics. In the case where the interface separates two fluids of different density in, for example, a rectangular container, the mass transfer due to vertical motion near the endwalls requires a counterflow in the interior region that can lead to a Kelvin-Helmholtz type instability and a ``frozen wave" pattern. In microgravity, the dominance of surface forces favors non-flat equilibrium configurations and the distinction between vertical and horizontal applied forcing can be lost. Hysteresis and multiplicity of solutions are more common, especially in non-wetting systems where disconnected (partial) volumes of fluid can be established. Furthermore, the vibrational field contributes a dynamic pressure term that competes with surface tension to select the (time averaged) shape of the surface. These new (quasi-static) surface configurations, known as vibroequilibria, can differ substantially from the hydrostatic state. There is a tendency for the interface to orient perpendicular to the vibrational axis and, in some cases, a bulge or cavity is induced

  9. Balloon Measurements of Electric Fields in Thunderstorms: A Modern Version of Benjamin Franklin's Kite

    Science.gov (United States)

    Marshall, T. C.; Stolzenburg, M.

    2006-12-01

    One of Benjamin Franklin's most famous experiments was the kite experiment, which showed that thunderstorms are electrically charged. It is not as commonly noted that the kite experiment was also one of the the first attempts to make an in situ measurement of any storm parameter. Franklin realized the importance of making measurements close to and within storms, and this realization has been shared by later atomspheric scientists. In this presentation we focus on a modern version of Franklin's kite--instrumented balloons--used for in situ measurements of electric field and other storm parameters. In particular, most of our knowledge of the charge structure inside thunderstorms is based on balloon soundings of electric field. Balloon measurements of storm electricity began with the work of Simpson and colleagues in the 1930's and 1940's. The next major instrumentation advances were made by Winn and colleagues in the 1970's and 1980's. Today's instruments are digital versions of the Winn design. We review the main instrument techniques that have allowed balloons to be the worthy successors to kites. We also discuss some of the key advances in our understanding of thunderstorm electrification made with in situ balloon-borne instruments.

  10. Approaching the knee -- balloon-borne observations of cosmic ray composition

    CERN Document Server

    Cherry, M L

    2005-01-01

    Below the knee in the cosmic ray spectrum, balloon and spacecraft experiments offer the capability of direct composition and energy measurements on the primary particles. A major difficulty is obtaining enough exposure to extend the range of direct measurements sufficiently high in energy to permit overlap with ground-based observations. Presently, balloon and space measurements extend only up to ~100 TeV, well below the range of ground-based experiments. The prospect of Ultra-Long Duration Balloon missions offers the promise of multiple long flights that can build up exposure. The status of balloon measurements to measure the high energy proton and nuclear composition and spectrum is reviewed, and the statistical considerations involved in searching for a steepening in the spectrum are discussed. Given the very steeply falling spectrum, it appears unlikely that balloon experiments will be able to extend the range of direct measurements beyond 1000 TeV any time in the near future. Especially given the recent ...

  11. Formation and evolution of flapping and ballooning waves in magnetospheric plasma sheet

    Science.gov (United States)

    Ma, J. Z. G.; Hirose, A.

    2016-05-01

    By adopting Lembége & Pellat's 2D plasma-sheet model, we investigate the flankward flapping motion and Sunward ballooning propagation driven by an external source (e.g., magnetic reconnection) produced initially at the sheet center. Within the ideal MHD framework, we adopt the WKB approximation to obtain the Taylor-Goldstein equation of magnetic perturbations. Fourier spectral method and Runge-Kutta method are employed in numerical simulations, respectively, under the flapping and ballooning conditions. Studies expose that the magnetic shears in the sheet are responsible for the flapping waves, while the magnetic curvature and the plasma gradient are responsible for the ballooning waves. In addition, the flapping motion has three phases in its temporal development: fast damping phase, slow recovery phase, and quasi-stabilized phase; it is also characterized by two patterns in space: propagating wave pattern and standing wave pattern. Moreover, the ballooning modes are gradually damped toward the Earth, with a wavelength in a scale size of magnetic curvature or plasma inhomogeneity, only 1-7% of the flapping one; the envelops of the ballooning waves are similar to that of the observed bursty bulk flows moving toward the Earth.

  12. A review of recent results in gamma-ray astronomy obtained from high-altitude balloons

    Science.gov (United States)

    Teegarden, B. J.

    1994-06-01

    This paper reviews recent results in gamma-ray astronomy obtained from experiments flown on high-altitude balloons. New generation balloon-borne imaging experiments have produced the first gamma-ray maps of the Galactic center (GC) region. Balloon flights of new gamma-ray spectrometers with improved sensitivity have provided important new information on the GC annihilation line. For the first time, the narrow 511 keV line as been resolved (FWHM approx. = 3 keV). A very interesting spectral feature at approximately 170 keV has been attributed to backscattered annihilation, probably from the vicinity of a compact object. New results from the Compton Gamma-Ray Observatory (CGRO)/OSSE and Granat/SIGMA experiments on the annihilation line, when considered together with the recent balloon results, have added greatly to our knowledge and understanding of the origin and distribution of this emission. Balloon-borne instruments have made important measurements of gamma-ray continuum and line emission from SN 1987A. The GRIS spectrometer unambiguously resolved the 847 and 1238 keV line emission from radioactive Co-56 synthesized during the explosion. This data indicated that simple spherically symmetric and homogeneous models did not provide an adequate description of the expanding SN shell.

  13. Balloon Dilatation of Pediatric Subglottic Laryngeal Stenosis during the Artificial Apneic Pause: Experience in 5 Children

    Directory of Open Access Journals (Sweden)

    J. Lisý

    2014-01-01

    Full Text Available Introduction. Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim of procedure in apneic pause is to avoid new insertion of tracheostomy cannula. Patients and Methods. The authors performed balloon dilatation of subglottic laryngeal strictures (SGS in 5 children (3 girls and 2 boys without tracheotomy. Two of them with traumatic and inflammatory SGS had a tracheal cannula removed in the past. The other 3 children with postintubation SGS had never had a tracheostomy before. The need for tracheostomy due to worsening stridor was imminent for all of them. Results. The total of seven laryngeal dilatations by balloon esophagoplasty catheter in apneic pause was performed in the 5 children. The procedure averted the need for tracheostomy placement in 4 of them (80%. Failure of dilatation in girl with traumatic stenosis and concomitant severe obstructive lung disease led to repeated tracheostomy. Conclusion. Balloon dilatation of laryngeal stricture could be done in the absence of tracheostomy in apneic pause. Dilatation averted threatening tracheostomy in all except one case. Early complication after the procedure seems to be a negative prognostic factor for the outcome of balloon dilatation.

  14. Assessment of risk of carotid occlusion with balloon Matas testing and dynamic computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Terada, Tomoaki; Okuno, Takashi; Moriwaki, Hiroshi; Nakai, Ekini; Nishiguchi, Takashi; Hayashi, Seiji; Komai, Norihiko.

    1988-02-01

    Temporary occlusion of the internal carotid artery with a balloon catheter (balloon Matas test) and simultaneous dynamic computed tomographic scanning (DCT) were performed in four patients with intracranial aneurysms to determine their tolerance for permanent carotid occlusion. Five DCT parameters were evaluated: appearance time, peak time, peak height fitting, first effective moment, and transit time. The patients were characterized into three types: type I (2 patients) - lack of neurological deficit during the balloon Matas test and equally preserved cerebral blood flow (CBF) in the two hemispheres on DCT during carotid occlusion, type II (one patient) - a decreased CBF on the occluded side on DCT despite the lack of neurological deficit; type III (one patient) - neurological signs, such as disturbance of consciousness, aphasia, and right hemiparesis occuring immediately after the start of the balloon Matas test, and a decreased CBF in the region of the middle and anterior cerebral arteries on the occluded side. In the type III patient, occlusion of the internal carotid artery is contraindicated unless an EC-IC bypass procedure that can rapidly provide a large supply of blood is performed. It can be concluded that the balloon Matas/DCT method offers a reliable means of predicting the risk of carotid ligation. (Namekawa, K.).

  15. Status of the Balloon-Borne X-ray Polarimetry Mission X-Calibur

    Science.gov (United States)

    Krawczynski, Henric; Kislat, Fabian; Stuchlik, David; Okajima, Takashi; de Geronimo, Gianluigi

    2016-04-01

    We report on the status of the balloon borne hard X-ray polairmetry mission X-Calibur. The missions combines a focussing hard X-ray mirror from the InFOCuS collaboration with a scattering polarimeter and the WASP (Wallops Arc Second Pointer) pointing system. The mission is scheduled for a conventonal ~1 day balloon flight in Fall 2016 and a long duration (~30 day) balloon flight from McMurdo (Ross Island) in 2018/2019. X-Calibur will allow us to measure ~5% polarization fractions for strong sources with a Crab-like enegry spectra and fluxes. The science targets of the first balloon flights will include the stellar mass black holes GRS 1915+105 and Cyg X-1, Her X-1, Sco X-1, and the Crab nebula and pulsar. The long duration balloon flight will target several X-ray binaries and the extragalactic mass accreting supermassive black hole Cen A. In this contribution we give an update on the status of the mission, and the expected science return.

  16. Combined CT and fluoroscopic guidance of balloon kyphoplasty versus fluoroscopy-only procedures

    Energy Technology Data Exchange (ETDEWEB)

    Amoretti, Nicolas; Marcy, Pierre-Yves; Lesbats-Jacquot, Virginie; Fonquerne, Marie-Eve; Hericord, Olivier; Maratos, Yvonne [Centre Hospitalier Universitaire de Nice, Service de Radiologie, Nice (France); Hovorka, Istvan [Centre Hospitalier Universitaire de Nice, Spine Surgery Department, Nice (France); Roux, Christian; Euller-Ziegler, Liana [Centre Hospitalier Universitaire de Nice, Rheumatology Department, Nice (France)

    2009-07-15

    To evaluate the performance of combined (computed tomography (CT) and fluoroscopic) guidance of balloon kyphoplasty in comparison to fluoroscopic guidance alone. Forty-one kyphoplasties were performed between January 2005 and March 2006 according to two different protocols. Study group 1 consisted of 20 consecutive patients with 20 balloon kyphoplasty procedures under dual guidance (CT scan and fluoroscopy) for osteoporotic or traumatic vertebral fractures. Study group 2 consisted of 21 consecutive patients in whom kyphoplasty was performed with fluoroscopy alone. Visualization of the pedicles, the final of the balloon position, and cement distribution were evaluated(1 - poor, 2 - intermediate, 3 - good). Combined use of CT and fluoroscopy (group 1) was superior in identifying the pedicles (100% versus 66.7%, p = 0.009) and balloon placement (100% versus 71.4%, p = 0.02) but not in monitoring of cement distribution within the vertebral body (100% versus 90.5%, p = 0.49). The difference between the two groups was more pronounced in the thoracic spine than in the lumbar spine. CT/fluoroscopic guidance of kyphoplasty combines safe CT-guided insertion of the osteointroducers and balloons as well as fluoroscopic real-time monitoring of polymethylmethacrylate injection. (orig.)

  17. Parallel wire balloon angioplasty for undilatable venous stenosis in hemodialysis fistula

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Tae Beom; You, Jin Jong; Cho, Jae Min [Gyeongsang National University Hospital, Jinju (Korea, Republic of)] (and others)

    2007-05-15

    The purpose of this study was to assess the value of the parallel wire balloon angioplasty technique for treating dysfunctional hemdialysis fistula with rigid stenosis, and this type of lesion was resistant to conventional angioplasty. Between March 2002 and August 2003, we included 6 patients (mean age: 59, males: 2, females: 4) who were treated via parallel the wire balloon angioplasty technique and their hemodialysis fistula has stenoses that were resistant to conventional angioplasty. We performed conventional angioplasty in all patients, but we failed to achieve sufficient dilatation. In the cases of highly resistant stenosis, an additional 0.016 inch wire was inserted into the 7 F vascular sheath. During angioplasty, a 0.016 inch guide wire was inserted between the balloon and the stenosis and then it was pushed to and fro until the balloon indentation disappeared. After the procedure, we performed angiography to identify the residual stenosis and the procedure-related complications. The undilatable stenoses in 5 patients were successfully resolved without complications via the parallel wire angioplasty technique. In one patient, indentation of balloon was not resolved, but the residual stenosis was both minimal and hemodynamically insignificant. The parallel wire angioplasty technique seems to be a feasible and cost-effective method for treating a dysfunctional hemodialysis fistula with undilatable and rigid stenosis.

  18. Balloon catheter dilation technology combined with a fibrolaryngoscope to treat a maxillary sinus cyst.

    Science.gov (United States)

    Xiao, Jianxin; Chen, Junming; Wang, Yuejian

    2016-02-01

    A prospective randomized controlled study was conducted to investigate the effect of balloon catheter dilation technology combined with a fibrolaryngoscope in the treatment of a maxillary sinus cyst. The clinical data of 14 cases (19 maxillary sinuses) with balloon catheter dilation technology combined with a fibrolaryngoscope to remove sinus cysts (balloon group) and 16 cases (23 maxillary sinuses) with conventional nasal endoscopic sinus surgery to remove sinus cysts (conventional group) were analyzed. All cases have completed the preoperative and postoperative SNOT-20, nasal endoscopy and coronal sinus CT scan. Lund-Kennedy endoscopic and Lund-Mackay CT scan staging scores were recorded. All patients were followed up for 24 weeks after the operation. The SNOT-20 scores, Lund-Kennedy endoscopic and Lund-Mackay CT scan staging scores were lower in the balloon group than that in the control group. Balloon catheter dilation technology combined with a fibrolaryngoscope can effectively preserve the function and structures of the nasal cavity and sinus, making it a good choice in the treatment of a retention cyst of the maxillary sinus.

  19. Instabilities, turbulence and transport in a magnetized plasma; Instabilites, turbulence et transport dans un plasma magnetise

    Energy Technology Data Exchange (ETDEWEB)

    Garbet, X

    2001-06-01

    The purpose of this work is to introduce the main processes that occur in a magnetized plasma. During the last 2 decades, the understanding of turbulence has made great progress but analytical formulas and simulations are far to produce reliable predictions. The values of transport coefficients in a tokamak plasma exceed by far those predicted by the theory of collisional transport. This phenomenon is called abnormal transport and might be due to plasma fluctuations. An estimation of turbulent fluxes derived from the levels of fluctuations, is proposed. A flow description of plasma allows the understanding of most micro-instabilities. The ballooning representation deals with instabilities in a toric geometry. 3 factors play an important role to stabilize plasmas: density pinch, magnetic shear and speed shear. The flow model of plasma gives an erroneous value for the stability threshold, this is due to a bad description of the resonant interaction between wave and particle. As for dynamics, flow models can be improved by adding dissipative terms so that the linear response nears the kinetic response. The kinetic approach is more accurate but is complex because of the great number of dimensions involved. (A.C.)

  20. Stability and instability in quantum mechanics

    International Nuclear Information System (INIS)

    This work is an attempt to describe the problem of stability and instabilities of quantum systems and involving very delicate experiments in molecular physics and solid state physics. A kind of transition to chaos occurs and few theoretical models have been proposed to investigate such a transition but it is better to use the term instabilities waiting for calling such an effect quantum chaos

  1. Energetic particle instabilities in fusion plasmas

    NARCIS (Netherlands)

    Sharapov, S. E.; Alper, B.; Berk, H. L.; Borba, D. N.; Breizman, B. N.; Challis, C. D.; Classen, I.G.J.; Edlund, E. M.; Eriksson, J.; Fasoli, A.; Fredrickson, E. D.; Fu, G. Y.; Garcia-Munoz, M.; Gassner, T.; Ghantous, K.; Goloborodko, V.; Gorelenkov, N. N.; Gryaznevich, M. P.; Hacquin, S.; Heidbrink, W. W.; Hellesen, C.; Kiptily, V. G.; Kramer, G. J.; Lauber, P.; Lilley, M. K.; Lisak, M.; Nabais, F.; Nazikian, R.; Nyqvist, R.; Osakabe, M.; C. Perez von Thun,; Pinches, S. D.; Podesta, M.; Porkolab, M.; Shinohara, K.; Schoepf, K.; Todo, Y.; Toi, K.; VanZeeland, M. A.; Voitsekhovich, I.; White, R. B.; Yavorskij, V.; ITPA EP TG Contributors,; JET-EFDA Contributors,

    2013-01-01

    Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfvén instabilities and modelling tools developed world-wide, and discus

  2. Cultural diversity, economic development and societal instability

    Science.gov (United States)

    Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.

    2007-01-01

    Background. Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation on ?? diversity, but also diversity between a nation and its neighbours or ?? diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings. We assembled a large cross-national dataset with information on ?? and ?? cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different type and domains of diversity have interacting effects. As previously documented, linguistic ?? diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For ?? diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious ?? diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between, neighboring nations has the opposite effect, decreasing societal instability.

  3. The short circuit instability in protoplanetary disks

    DEFF Research Database (Denmark)

    Hubbard, A.; McNally, C.P.; Mac Low, M.M.;

    2013-01-01

    We introduce a magneto-hydrodynamic instability which occurs, among other locations, in the inner, hot regions of protoplanetary disks, and which alters the way in which resistive dissipation of magnetic energy into heat proceeds. This instability can be likened to both an electrical short circuit...

  4. Cultural diversity, economic development and societal instability.

    Directory of Open Access Journals (Sweden)

    Daniel Nettle

    Full Text Available BACKGROUND: Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation or alpha diversity, but also diversity between a nation and its neighbours or beta diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. METHODOLOGY/PRINCIPAL FINDINGS: We assembled a large cross-national dataset with information on alpha and beta cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different types and domains of diversity have interacting effects. As previously documented, linguistic alpha diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For beta diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious beta diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. CONCLUSIONS: Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between neighboring nations has the opposite effect, decreasing societal instability.

  5. Travelling-wave-induced instability of structures

    International Nuclear Information System (INIS)

    The effect of transmission time of propagating disturbances on the dynamic instability of structures is discussed in this paper. Through a parametric study it is shown that for certain values of transmission time and wave frequency parameters, the structure may become dynamically unstable. An example is worked out, and graphical results depicting the regions of instability are presented

  6. Comparison of instability theory with simulation results

    International Nuclear Information System (INIS)

    The results of a quantitative comparison between linear instability theory and simulation results for a third order charge fluctuation mode in a quadrupole - focused beam are summarized. The theory is found to provide a good account of the initial instability exhibited by the simulation computations

  7. Plasma instabilities in high electric fields

    DEFF Research Database (Denmark)

    Morawetz, K.; Jauho, Antti-Pekka

    1994-01-01

    expression is derived for the nonequilibrium dielectric function epsilon(K, omega). For certain values of momenta K and frequency omega, Imepsilon(K, omega) becomes negative, implying a plasma instability. This new instability exists only for strong electric fields, underlining its nonequilibrium origin....

  8. On the descriptions of beam instabilities

    CERN Document Server

    Maillard, Antoine

    2016-01-01

    We investigate two interesting features of beam instabilities in accelerators : First, we provide the equivalence between two models to describe transverse instabilities, the circulant matrix model (based on a longitudinal phase space discretization) and the Vlasov formalism. Secondly, we show how to derive dispersion integrals for transverse detuning effects in the Vlasov formalism, thus allowing for Landau damping mechanism.

  9. Hydrodynamic Instabilities in Rotating Fluids

    Institute of Scientific and Technical Information of China (English)

    KarlBuehler

    2000-01-01

    Rotating flow systems are often used to study stability phenomena and structure developments.The closed spherical gap prblem is generalized into an open flow system by superimposing a mass flux in meridional direction.The basic solutions at low Reynolds numbers are described by analytical methods.The nonlinear supercritical solutions are simulated numerically and realized in experiments.Novel steady and time-dependent modes of flows are obtained.The extensive results concern the stability behaviour.non-uniqueness of supercritical solutions,symmetry behaviour and transitions between steady and time-dependent solutions.The experimental investigations concern the visualization of the various instabilities and the quatitative description of the flow structures including the laminar-turbulent transition.A Comparison between theoretical and experimental results shows good agreement within the limit of rotational symmetric solutions from the theory.

  10. The Magnetoviscous-thermal Instability

    CERN Document Server

    Islam, Tanim

    2011-01-01

    Accretion flows onto underluminous black holes, such as Sagittarius A* at the center of our galaxy, are dilute (mildly collisional to highly collisionless), optically thin, and radiatively inefficient. Therefore, the accretion properties of such dilute flows are expected to be modified by their large viscosities and thermal conductivities. Second, turbulence within these systems needs to transport angular momentum as well as thermal energy generated through gravitational infall outwards in order to allow accretion to occur. This is in contrast to classical accretion flows, in which the energy generated through accretion down a gravitational well is locally radiated. In this paper, using an incompressible fluid treatment of an ionized gas, we expand on previous research by considering the stability properties of a magnetized rotating plasma wherein the thermal conductivity and viscosity are not negligible and may be dynamically important. We find a class of MHD instabilities that can transport angular momentum...

  11. Instability Threshold “Hysteresis”

    Directory of Open Access Journals (Sweden)

    Agnes Muszynska

    1999-01-01

    Full Text Available The transient process which starts at the instability threshold of a rotor rotating in a fluid environment, and ends up in the limit cycle of self-excited vibrations known as fluid whirl or fluid whip, is discussed in this paper. A one-lateral-mode, isotropic, nonlinear model of the rotor with fluid interaction allows for exact particular solutions and an estimation of the transient process. The fluid interacting with the rotor is contained in a small radial clearance area, such as in bearings, seals, or rotor-to-stator clearances, and its effects are represented by fluid film radial stiffness, damping, and fluid inertia rotating at a different angular velocities.

  12. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.;

    2009-01-01

    -positive breast cancer and occurs frequently in basal-like and Her2-positive cases. In diploid cells, but not in chromosomally unstable cells, paclitaxel causes repression of CIN-survival genes, followed by cell death. In the OV01 ovarian cancer clinical trial, a high level of CIN was associated with taxane...... chromosomal instability (CIN). Silencing 22/50 of these genes, many of which are involved in DNA repair, caused cancer cell death, suggesting that these genes are involved in the survival of aneuploid cells. Overexpression of these "CIN-survival'' genes is associated with poor outcome in estrogen receptor...... resistance but carboplatin sensitivity, indicating that CIN may determine MTS response in vivo. Thus, pretherapeutic assessment of CIN may optimize treatment stratification and clinical trial design using these agents....

  13. Transient spirals as superposed instabilities

    CERN Document Server

    Sellwood, J A

    2014-01-01

    We present evidence that recurrent spiral activity, long manifested in simulations of disk galaxies, results from the super-position of a few transient spiral modes. Each mode lasts between five and ten rotations at its corotation radius where its amplitude is greatest. The scattering of stars as each wave decays takes place over narrow ranges of angular momentum, causing abrupt changes to the impedance of the disk to subsequent traveling waves. Partial reflections of waves at these newly created features, allows new standing-wave instabilities to appear that saturate and decay in their turn, scattering particles at new locations, creating a recurring cycle. The spiral activity causes the general level of random motion to rise, gradually decreasing the ability of the disk to support further activity unless the disk contains a dissipative gas component from which stars form on near-circular orbits. We also show that this interpretation is consistent with the behavior reported in other recent simulations with l...

  14. Taylor instability in rhyolite lava flows

    Science.gov (United States)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  15. Parametric instabilities in the LCGT arm cavity

    Science.gov (United States)

    Yamamoto, K.; Uchiyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.; Numata, K.

    2008-07-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (USA). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta2O5) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  16. Parametric instabilities in the LCGT arm cavity

    CERN Document Server

    Yamamoto, K; Miyoki, S; Ohashi, M; Kuroda, K; Numata, K

    2008-01-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (U.S.A.). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta$_2$O$_5$) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  17. Taming contact line instability for pattern formation

    Science.gov (United States)

    Deblais, A.; Harich, R.; Colin, A.; Kellay, H.

    2016-08-01

    Coating surfaces with different fluids is prone to instability producing inhomogeneous films and patterns. The contact line between the coating fluid and the surface to be coated is host to different instabilities, limiting the use of a variety of coating techniques. Here we take advantage of the instability of a receding contact line towards cusp and droplet formation to produce linear patterns of variable spacings. We stabilize the instability of the cusps towards droplet formation by using polymer solutions that inhibit this secondary instability and give rise to long slender cylindrical filaments. We vary the speed of deposition to change the spacing between these filaments. The combination of the two gives rise to linear patterns into which different colloidal particles can be embedded, long DNA molecules can be stretched and particles filtered by size. The technique is therefore suitable to prepare anisotropic structures with variable properties.

  18. Treatment of the subject of tearing instability

    International Nuclear Information System (INIS)

    A simple approach is taken to the mechanics of potential instability associated with the steady tearing portion of J-Integral R-curves. The analysis is developed from simple examples of structural component (or test specimen) configurations with cracks, examining their instability possibilities individually, in order to draw more general conclusions about elastic-plastic cracking instability as contrasted to linear-elastic behavior. Finally, an attempt is made to model a more local cleavage-like instability for material in the fracture process zone just ahead of a crack tip. Results are then presented of a testing program which clearly demonstrates the appropriateness of the tearing instability analysis and which illustrates its broad potential for future application, as well as presenting guidelines for its further development. The material selected for analysis was Ni-Cr-Mo-V rotor steel

  19. MHD instability with dawn-dusk symmetry in near-Earth plasma sheet during substorm growth phase*

    Science.gov (United States)

    Zhu, P.; Raeder, J.; Hegna, C.; Sovinec, C.

    2010-12-01

    Recent global MHD simulations of March 23, 2007 THEMIS substorm event using the OpenGGCM code have confirmed the presence of both high-ky ballooning modes and zero-ky instabilities in the near-Earth plasma sheet during the substorm growth phase [Raeder et al 2010]. These results are consistent with findings from earlier analyses [Siscoe et al 2009; Zhu et al 2009]. Here ky is the azimuthal wavenumber in the dawn-dusk direction. However, the nature and role of the ky=0 mode, as well as its interaction with the high ky ballooning modes, in the process leading to the expansion onset remain unclear. In this work, we focus on the stability properties of the ky=0 mode. A re-evaluation of the tail-tearing mode criterion by Sitnov and Schindler (2009) suggested that the dipolarization front (DF) structure identified in THEMIS observations [Runov et al 2009] could be tearing-unstable. Linear calculations using the NIMROD code have found a growing tearing mode in a generalized Harris sheet with a DF-like structure, which is also a unique feature closely correlated with the appearance of zero-ky mode in the OpenGGCM simulation. The ideal-MHD energy principle analysis is used to address the question whether the ky=0 mode is an ideal or resistive MHD instability. We further compare the linear and nonlinear tail-tearing mode in NIMROD simulations with the ky=0 mode from OpenGGCM simulations. *Supported by NSF Grants AGS-0902360 and PHY-0821899. References: Raeder, J., P. Zhu, Y.-S. Ge, and G. Siscoe (2010), Tail force imbalance and ballooning instability preceding substorm onset, submitted to J. Geophys. Res. Runov, A., et al. (2009), Geophys. Res. Lett., 36, L14106. Siscoe, G.L., M.M. Kuznetsova, and J. Raeder (2009), Ann. Geophys., 27, 3141. Sitnov, M.I. and K. Schindler (2010), Geophys. Res. Lett., 37, L08102. Zhu, P., J. Raeder, K. Germaschewski, and C.C. Hegna (2009), Ann. Geophys., 27, 1129.

  20. New developments in the clinical use of drug-coated balloon catheters in peripheral arterial disease

    Science.gov (United States)

    Naghi, Jesse; Yalvac, Ethan A; Pourdjabbar, Ali; Ang, Lawrence; Bahadorani, John; Reeves, Ryan R; Mahmud, Ehtisham; Patel, Mitul

    2016-01-01

    Peripheral arterial disease (PAD) involving the lower extremity is a major source of morbidity and mortality. Clinical manifestations of PAD span the spectrum from lifestyle limiting claudication to ulceration and gangrene leading to amputation. Advancements including balloon angioplasty, self-expanding stents, drug-eluting stents, and atherectomy have resulted in high technical success rates for endovascular therapy in patients with PAD. However, these advances have been limited by somewhat high rates of clinical restenosis and clinically driven target lesion revascularization. The recent introduction of drug-coated balloon technology shows promise in limiting neointimal hyperplasia induced by vascular injury after endovascular therapies. This review summarizes the contemporary clinical data in the emerging area of drug-coated balloons.