Sample records for ballooning instability

  1. Deployment Instabilities of Lobed-Pumpkin Balloon (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. Numerical Modelling Of Pumpkin Balloon Instability (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.

  3. 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


    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.

  4. Three-dimensional geometry of magnetic reconnection induced by ballooning instability in a generalized Harris sheet (United States)

    Zhu, Ping; Bhattacharjee, Amitava; Sangari, Arash; Wang, Zechen; Bonofiglo, Phillip


    We report for the first time the intrinsically three-dimensional (3D) geometry of the magnetic reconnection process induced by ballooning instability in a generalized Harris sheet. The spatial distribution and the structure of the quasi-separatrix layers, as well as their temporal emergence and evolution, indicate that the associated magnetic reconnection can only occur in a 3D geometry, which is irreducible to that of any two-dimensional reconnection process. Such a finding provides a new perspective to the long-standing controversy over the substorm onset problem and elucidates the combined roles of reconnection and ballooning instabilities. It also connects to the universal presence of 3D reconnection processes previously discovered in various natural and laboratory plasmas.

  5. Structure and consequences of the kinetic ballooning/interchange instability in the magnetotail (United States)

    Pritchett, P. L.; Coroniti, F. V.


    AbstractThe structure and dynamical consequences of the kinetic ballooning/interchange instability (BICI) that can be excited in the curved magnetic geometry characteristic of the terrestrial plasma sheet are investigated by means of three-dimensional electromagnetic particle-in-cell simulations. Compared with earlier studies that considered a single Bz minimum configuration with an extremely large midtail field, additional simulations are performed in which this maximum is reduced to a more realistic value, the dependence on the values of the plasma beta and of the mass and temperature ratios mi/me and Ti/Te is investigated, and the limiting case of a constant Bz profile is examined. The general properties of the BICI modes are found to be unaltered by these changes. Significantly, the BICI excitation is found not to require an explicit tailward magnetic field gradient; it appears to be sufficient for the entropy to decrease with distance down the tail. The BICI wavelength varies inversely with Bz, and the eigenmodes are strongly field aligned with parallel electron flows comparable to the ion thermal velocity. In the edge of the plasma sheet, the oscillations in Bx and Bz have comparable magnitude. Once excited, the growth of the modes is robust and leads to the formation of intense interchange heads that propagate earthward. When the equatorial plasma beta is on the order of 500 or higher, the Bz field can be driven southward in the wake of the heads. This results in the onset of localized magnetic reconnection and a violent disruption of the plasma sheet.

  6. A Statistical study of plasma sheet oscillations with kinetic ballooning/interchange instability signatures using THEMIS spacecraft (United States)

    Jurisic, Mirjana; Panov, Evgeny; Nakamura, Rumi; Baumjohann, Wolfgang


    We use THEMIS data from 2010-2012 tail seasons to collect observations of plasma sheet oscillations with kinetic ballooning/interchange instability (BICI) signatures. Over seventy observations with closely located THEMIS probes P3-P5 reveal that BICI-like plasma sheet oscillations may appear at different magnetic local time. For these, we derive background plasma sheet parameters such as BZ, δBZ/δx and plasma beta, and investigate solar wind conditions. We also estimate the proper parameters of BICI-like oscillations such as frequency and amplitude. Based on this, we search for a relation between the background plasma sheet parameters and the proper parameters of BICI-like oscillations.

  7. Pumpkin Balloon


    Nishimura, Jun; 西村, 純


    The Pumpkin shaped balloons, which are the extreme case of the heart-type balloons had been studied as one of the promising candidate of the super pressure balloons. Here, detailed studies for the features of the pumpkin balloons are described, particularly by comparing with those of the spherical shaped super pressure balloons.

  8. Cleft formation in pumpkin balloons (United States)

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

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

  9. Stability of the pumpkin balloon (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

  10. GHOST balloons around Antarctica (United States)

    Stearns, Charles R.


    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.

  11. Clefting in pumpkin balloons (United States)

    Baginski, F.; Schur, W.

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

  12. Development of a balloon volume sensor for pulsating balloon catheters. (United States)

    Nolan, Timothy D C; Hattler, Brack G; Federspiel, William J


    Helium pulsed balloons are integral components of several cardiovascular devices, including intraaortic balloon pumps (IABP) and a novel intravenous respiratory support catheter. Effective use of these devices clinically requires full inflation and deflation of the balloon, and improper operating conditions that lead to balloon under-inflation can potentially reduce respiratory or cardiac support provided to the patient. The goal of the present study was to extend basic spirographic techniques to develop a system to dynamically measure balloon volumes suitable for use in rapidly pulsating balloon catheters. The dynamic balloon volume sensor system (DBVSS) developed here used hot wire anemometry to measure helium flow in the drive line from console to catheter and integrated the flow to determine the volume delivered in each balloon pulsation. An important component of the DBVSS was an algorithm to automatically detect and adjust flow signals and measured balloon volumes in the presence of gas composition changes that arise from helium leaks occurring in these systems. The DBVSS was capable of measuring balloon volumes within 5-10% of actual balloon volumes over a broad range of operating conditions relevant to IABP and the respiratory support catheter. This includes variations in helium concentration from 70-100%, pulsation frequencies from 120-480 beats per minute, and simulated clinical conditions of reduced balloon filling caused by constricted vessels, increased driveline, or catheter resistance.

  13. Mars Solar Balloon Lander Project (United States)

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

  14. Venus Altitude Cycling Balloon Project (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...

  15. Space Weather Ballooning (United States)

    Phillips, Tony; Johnson, Sam; Koske-Phillips, Amelia; White, Michael; Yarborough, Amelia; Lamb, Aaron; Herbst, Anna; Molina, Ferris; Gilpin, Justin; Grah, Olivia; Perez, Ginger; Reid, Carson; Harvey, Joey; Schultz, Jamie


    We have developed a "Space Weather Buoy" for measuring upper atmospheric radiation from cosmic rays and solar storms. The Buoy, which is carried to the stratosphere by helium balloons, is relatively inexpensive and uses off-the-shelf technology accessible to small colleges and high schools. Using this device, we have measured two Forbush Decreases and a small surge in atmospheric radiation during the St. Patrick's Day geomagnetic storm of March 2015.

  16. Obesity and gastric balloon

    Directory of Open Access Journals (Sweden)

    Mohammed I Yasawy


    Full Text Available Background: The obesity epidemic, which is among the most common nutritional disorders, is rising rapidly worldwide. It leads to several health problems such as metabolic disorders, stroke, and even cancer. Efforts to control obesity with exercise and diet have a limited value in obese patients and different approaches to do this have been tried. In this paper, we share our experience with bioenteric intragastric balloon (BIB in treating obesity: Its safety, tolerability, and its efficacy in weight reduction. Materials and Methods: From January 2009 to September 2012, a total of 190 gastric balloons was inserted on patients at the endoscopy unit in King Fahd Hospital of the University, Al-Khobar. This is an evaluation of the first 100 patients. All the patients had a body mass index of over 30 kg/m 2 and were within the age range of 17-55 with a mean age of 32 years. After consent, preballoon investigation tests and anesthesia evaluation, BIB was inserted under monitored anesthesia care sedation in the endoscopy suite. The balloon was filled with 500-700 mls of stained saline. All patients′ were given an analgesic and antiemetic for a week and antisecretory proton pump inhibitor′s for 6 months. Diet and the importance of the exercise were part of the preballoon insertion phase and protocol. The balloon was removed after 6-12 months. Results: The weight loss response to BIB in the 100 patients are classified into four groups: In the uncooperative, noncompliant patients - the maximum weight loss was 7 kg, while in the most compliant patients the weight loss reached up to 39 kg. In addition, there was significant improvement into diabetes mellitus, hypertension, dyslipidemia, and fatty liveras. Its safety and tolerability were extremely acceptable. Conclusion: Our data indicates that in well-selected patients, BIB is an effective device, which with minimum complications helps to achieve body weight loss and resolve many obesity related

  17. Breakthrough in Mars balloon technology (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.


    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.

  18. Titan Balloon Convection Model Project (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...

  19. Buddy balloon for TAVI. (United States)

    Balkin, Jonathan; Silberman, Shuli; Almagor, Yaron


    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.

  20. A Methane Balloon Inflation Chamber (United States)

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


    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.

  1. Nationwide Eclipse Ballooning Project (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


    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.

  2. Finite Larmor radius magnetohydrodynamic analysis of the ballooning modes in tokamaks*

    Institute of Scientific and Technical Information of China (English)

    Jiang Hai-Bin; Wang Ai-Ke; Peng Xiao-Dong


    In this paper,the effect of finite Larmor radius(FLR)on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic(FLR-MHD)theory.A linear FLR ballooning mode equation is derived in an '(s)-α' type equilibrium of circular-flux-surfaces,which is reduced to the ideal ballooning mode equation when the FLR effect is neglected.The present model reproduces some basic features of FLR effects on ballooning mode obtained previously by kinetic ballooning mode theories.That is,the FLR introduces a real frequency into ballooning mode and has a stabilising effect on ballooning modes(e.g.,in the case of high magnetic shear(s)≥ 0.8).In particular,some new properties of FLR effects on ballooning mode are discovered in the present research.Here it is found that in a high magnetic shear region((s)≥0.8)the critical pressure gradient(αc1,FLR)of ballooning mode is larger than the ideal one(αc,IMHD)and becomes larger and larger with the increase of FLR parameter b0.However,in a low magnetic shear region,the FLR ballooning mode is more unstable than the ideal one,and the αc,FLR is much lower than the αc,IMHD.Moreover,the present results indicate that there exist some new weaker instabilities near the second stability boundary(obtained from ideal MHD theory),which means that the second stable region becomes narrow.

  3. US Air Force Balloon Observations (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...

  4. US Monthly Pilot Balloon Observations (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly winds aloft summary forms summarizing Pilot Balloon observational data for the United States. Generally labeled as Form 1114, and then transitioning to Form...

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

  6. Sensor System for Super-Pressure Balloon Performance Modeling Project (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...

  7. Explosive Instability of Prominence Flux Ropes

    Energy Technology Data Exchange (ETDEWEB)

    Hurricane, O; Fong, R H L; Cowley, S C


    The rapid, Alfvenic, time scale of erupting solar-prominences has been an enigma ever since they where first identified. Investigators have proposed a variety of different mechanisms in an effort to account for the abrupt reconfiguration observed. No one mechanism clearly stands out as the single cause of these explosive events. Recent analysis has demonstrated that field lines in the solar atmosphere are metastable to ballooning type instabilities. It has been found previously that in ideal MHD plasmas marginally unstable ballooning modes inevitably become ''explosive'' evolving towards a finite time singularity via a nonlinear 3D instability called ''Nonlinear Magnetohydrodynamic Detonation.'' Thus, this mechanism is a good candidate to explain explosive events observed in the solar atmosphere of our star or in others.

  8. Structure variations of pumpkin balloon (United States)

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


    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.

  9. Balloon Exoplanet Nulling Interferometer (BENI) (United States)

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


    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.

  10. Yellow Balloon in a Briar Patch. (United States)

    Cooper, Frank; Fitzmaurice, Robert W.


    As part of a meteorology unit, sixth grade science students launched helium balloons with attached return postcards. This article describes Weather Service monitoring of the balloons and postcard return results. (MA)

  11. Mechanical instability

    CERN Document Server

    Krysinski, Tomasz


    This book presents a study of the stability of mechanical systems, i.e. their free response when they are removed from their position of equilibrium after a temporary disturbance. After reviewing the main analytical methods of the dynamical stability of systems, it highlights the fundamental difference in nature between the phenomena of forced resonance vibration of mechanical systems subjected to an imposed excitation and instabilities that characterize their free response. It specifically develops instabilities arising from the rotor-structure coupling, instability of control systems, the se

  12. Collective instabilities

    Energy Technology Data Exchange (ETDEWEB)

    K.Y. Ng


    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.

  13. Complications of balloon packing in epistaxis

    NARCIS (Netherlands)

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


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

  14. Ballonnen in zee = balloons as marine litter

    NARCIS (Netherlands)

    Franeker, van J.A.


    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

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

  16. 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)


    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.

  17. Pseudoperforation during kissing balloon angioplasty. (United States)

    Panetta, Carmelo J; Fasseas, Panayotis; Raveendran, Ganesh; Garratt, Kirk N


    We describe a case of apparent perforation during kissing balloon angioplasty of a bifurcation lesion. There was no evidence of perforation on follow-up angiography or via intravascular ultrasound. Possible etiologies include minimal perforation that immediately sealed postdeflation or forced contrast into the microvascular bed via a proximal side branch.

  18. Simulating clefts in pumpkin balloons (United States)

    Baginski, Frank; Brakke, Kenneth


    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.

  19. Ballooning mode spectrum in general toroidal systems

    Energy Technology Data Exchange (ETDEWEB)

    Dewar, R.L.; Glasser, A.H.


    A WKB formalism for constructing normal modes of short-wavelength ideal hydromagnetic, pressure-driven instabilities (ballooning modes) in general toroidal magnetic containment devices with sheared magnetic fields is developed. No incompressibility approximation is made. A dispersion relation is obtained from the eigenvalues of a fourth order system of ordinary differential equations to be solved by integrating along a line of force. Higher order calculations are performed to find the amplitude equation and the phase change at a caustic. These conform to typical WKB results. In axisymmetric systems, the ray equations are integrable, and semiclassical quantization leads to a growth rate spectrum consisting of an infinity of discrete eigenvalues, bounded above by an accumulation point. However, each eigenvalue is infinitely degenerate. In the nonaxisymmetric case, the rays are unbounded in a four dimensional phase space, and semiclassical quantization breaks down, leading to broadening of the discrete eigenvalues and accumulation point of the axisymmetric case into continuum bands. Analysis of a model problem indicates that the broadening of the discrete eigenvalues is numerically very small, the dominant effect being broadening of the accumulation point.

  20. Scientific ballooning in India: recent developments (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.

  1. Viscoelastic behaviour of pumpkin balloons (United States)

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


    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.

  2. Recombination instability

    DEFF Research Database (Denmark)

    D'Angelo, N.


    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) an af...

  3. Hyperspectral Polarimeter for Monitoring Balloon Strain Project (United States)

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

  4. Scientific Ballooning Activities and Recent Developments in Technology and Instrumentation of the TIFR Balloon Facility, Hyderabad (United States)

    Buduru, Suneel Kumar


    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.

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

    Institute of Scientific and Technical Information of China (English)



    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.

  6. [Carpal instability]. (United States)

    Redeker, J; Vogt, P M


    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.

  7. Intragastric balloon and multidisciplinary team

    Directory of Open Access Journals (Sweden)

    R. A. Mazure

    Full Text Available Background: The intragastric balloon is widely used for weight reduction in obese patients, but results are variable. We describe our results enhancing the importance of a Multidisciplinary Team (MT taking part in the treatment. Methods: A retrospective review was done concerning a total of 119 balloons , placed in 116 patients, under endoscopic control and conscious sedation, from May 2001 until August 2006. 49 patients were prepared and recommended to be followed by a MT in a physical unit, at least every 15 days during 6 months. 67 were indicated and followed by other colleagues, without MT. Removal was performed 6 months later. Results: Concerning our 49 patients, mean age was 38, 1 years, 31 female and 18 males, with BMI ranged between 32 and 63, average of 42. The average decrease of weight excess was 31, 85% (-4, 45-80, 4%, and the BMI diminished 5,3 points (from 13,6 to gain of 0,9. The treatment failed in 34,6 % of our patients -including 4 patients lost of follow-up (8, 16%-, compared with 53, 8% of patients without structured MT for selection and follow-up. Physical exercise enhanced markedly the results with 45, 8% of excess of weight loss in women and 39, 7% in males, compared with 14, 6 and 15, 6% in patients who didn't follow the program. The weight loss was mostly fat mass, 89,9% in men and 75,6% in women.- The results maintenance was obtained in 40% of patients one year later. There were no major complications; one balloon had to be removed at 3 weeks because of intolerance, another at 5 months because of gastroesophageal reflux. Conclusions: BIB is an effective help to achieve a short term weight loss in obese patients; nevertheless, good and long lasting results will depend on the modification of life style obtained by a multidisciplinary approach.


    Directory of Open Access Journals (Sweden)

    Ionescu Cristian


    Full Text Available There is an important link between the following two variables: financial instability and political instability. Often, the link is bidirectional, so both may influence each other. This is way the lately crisis are becoming larger and increasingly complex. Therefore, the academic environment is simultaneously talking about economic crises, financial crises, political crises, social crises, highlighting the correlation and causality between variables belonging to the economic, financial, political and social areas, with repercussions and spillover effects that extend from one area to another. Given the importance, relevance and the actuality of the ones described above, I consider that at least a theoretical analysis between economic, financial and political factors is needed in order to understand the reality. Thus, this paper aims to find links and connections to complete the picture of the economic reality.

  9. Paraplegia following intraaortic balloon circulatory assistance

    Directory of Open Access Journals (Sweden)

    Benício Anderson


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

  10. Global stability of the ballooning mode in a cylindrical model (United States)

    Mazur, N. G.; Fedorov, E. N.; Pilipenko, V. A.


    Ballooning disturbances in a finite-pressure plasma in a curvilinear magnetic field are described by the system of coupled equations for the Alfvén and slow magnetosonic modes. In contrast to most previous works that locally analyzed the stability of small-scale disturbances using the dispersion relationship, a global analysis outside a WKB approximation but within a simple cylindrical geometry, when magnetic field lines are circles with constant curvature, is performed in the present work. This model is relatively simple; nevertheless, it has the singularities necessary for the formation of the ballooning mode: field curvature and non-uniform thermal plasma pressure. If the disturbance finite radial extent is taken into account, the instability threshold increases as compared to a WKB approximation. The simplified model used in this work made it possible to consider the pattern of unstable disturbances at arbitrary values of the azimuthal wavenumber ( k y ). Azimuthally large-scale disturbances can also be unstable, although the increment increases with decreasing azimuthal scale and reaches saturation when the scales are of the order of the pressure nonuniformity dimension.

  11. Airborne Internet Providing Tethered Balloon System

    Directory of Open Access Journals (Sweden)

    Suvriti Dhawan1


    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.

  12. Stratospheric electric field measurements with transmediterranean balloons (United States)

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


    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.

  13. A balloon-borne integrating nephelometer

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.S.; Apple, M.L. (Sandia National Labs., Albuquerque, NM (USA)); Weiss, R.E. (Radiance Research, Seattle, WA (USA))


    A balloon-borne integrating nephelometer has been successfully developed and flown by Sandia National Laboratories and Radiance Research. This report details instrument design, calibration and data conversion procedure. Free and tethered balloon transport and telemetry systems are described. Data taken during March 1989 South-Central New Mexico free flight ascents are presented as vertical profiles of atmospheric particle scattering coefficient, temperature and balloon heading. Data taken during December 1989 Albuquerque, New Mexico tethered flights are also presented as vertical profiles. Data analysis shows superior instrument performance. 5 refs., 22 figs.

  14. Looners: Inside the world of balloon fetishism


    McIntyre, Karen E


    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 ...

  15. Shielded Mars Balloon Launcher (SMBL) Project (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....

  16. 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


    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. ...

  17. Retrieving Balloon Data in Flight Project (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 times,...

  18. Magnetometer for Balloons and UAVs Project (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...

  19. Power Systems Design for Long Duration Ballooning (United States)

    Stilwell, Bryan; Chuzel, Alain


    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.

  20. Imaging Sunlit Aurora from Balloon (United States)

    Lummerzheim, D.; Zhou, X.


    Since 1892 when aurora was first imaged by Martin Brendel, useful auroral images have been obtained only when the aurora is in darkness. While UV imagers onboard satellite provide global auroral dynamics, the sunlit aurora in the UV band is overwhelmed by the UV airglow that has the same wavelengths with the UV auroral emissions. The visible band imaging is feasible only when the aurora is in darkness to avoid the sunlight contamination. However, sunlit aurora (such as dayside aurora) is closely related to the solar wind - magnetosphere - ionosphere coupling. In addition, limited land area has badly restricted the capability of imaging dayside aurora from the northern hemisphere and nightside aurora from the southern hemisphere. We have confirmed that sunlit aurora can be imaged using a near-infrared (NIR) camera on board the balloon platform flying in Antarctica or Arctic. This method provides a unique capability for dayside and conjugate auroral investigations. Scientific questions that can be addressed by such observations include how does the dayside aurora respond to solar wind transient variations? Are auroras hemispherically symmetric? Are auroral forms and their variations under sunlight the same as those in darkness? etc. The new method is also cost effective comparing to space-borne imagers, and offers capabilities not obtainable from space and the ground. With the accomplishment of identifying auroral dynamics in sunlight and darkness, in the south and north simultaneously, our knowledge and understanding of auroral phenomenon and its causes will be expanded.

  1. Japan-Indo collaboration on balloon observations (United States)

    Makino, Fumiyoshi

    Japan-Indo collaboration on balloon observations of cosmic X-ray sources was started in 1969 by the late S. Hayakawa of Nagoya Univ. and B. V. Sreekantan of TIFR. Cosmic background X-ray and soft gamma-ray spectra, simultaneous X-ray and optical flux variation, and size of X-ray emitting region of Crab Nebula were observed successfully by balloon flights at Hyderabad in 1969-1975. H. Shibai of Nagoya Univ. and T. N. Rengarajan of TIFR have organized collaboration on far infrared sky survey at wavlength of 150 micron emitted from CII. By employing improved detectors, CII distribution of Orion Nebula has been obtained in good accuracy by more than ten balloon flights in 1999-2008.

  2. Near ultraviolet spectrograph for balloon platform (United States)

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


    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. 75 FR 33838 - National Environmental Policy Act; Scientific Balloon Program (United States)


    ... SPACE ADMINISTRATION National Environmental Policy Act; Scientific Balloon Program AGENCY: National... Draft Programmatic Environmental Assessment (PEA) and Draft Finding of No Significant Impact (FONSI) for NASA's Scientific Balloon Program. SUMMARY: Pursuant to the National Environmental Policy Act of...

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

    CERN Document Server

    Gorham, Peter W


    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.

  5. There is a Text in 'The Balloon'

    DEFF Research Database (Denmark)

    Elias, Camelia


    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...

  6. Cutting balloon angioplasty for intrastent restenosis treatment

    Directory of Open Access Journals (Sweden)

    João Orávio de Freitas Jr


    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.

  7. On the inflation of a rubber balloon (United States)

    Vandermarlière, Julien


    It is a well-known fact that it is difficult to start a balloon inflating. But after a pressure peak that occurs initially, it becomes far easier to do it! The purpose of this article is to establish the experimental pressure-radius chart for a rubber balloon and to compare it to the theoretical one. We will demonstrate that the barometer of a smartphone is a very suitable tool to reach this goal. We hope that this phenomenon will help students realize that sometimes very simple questions can lead to very interesting and counterintuitive science.

  8. High altitude balloon experiments at IIA (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.

  9. Electron heat flux instability (United States)

    Saeed, Sundas; Sarfraz, M.; Yoon, P. H.; Lazar, M.; Qureshi, M. N. S.


    The heat flux instability is an electromagnetic mode excited by a relative drift between the protons and two-component core-halo electrons. The most prominent application may be in association with the solar wind where drifting electron velocity distributions are observed. The heat flux instability is somewhat analogous to the electrostatic Buneman or ion-acoustic instability driven by the net drift between the protons and bulk electrons, except that the heat flux instability operates in magnetized plasmas and possesses transverse electromagnetic polarization. The heat flux instability is also distinct from the electrostatic counterpart in that it requires two electron species with relative drifts with each other. In the literature, the heat flux instability is often called the 'whistler' heat flux instability, but it is actually polarized in the opposite sense to the whistler wave. This paper elucidates all of these fundamental plasma physical properties associated with the heat flux instability starting from a simple model, and gradually building up more complexity towards a solar wind-like distribution functions. It is found that the essential properties of the instability are already present in the cold counter-streaming electron model, and that the instability is absent if the protons are ignored. These instability characteristics are highly reminiscent of the electron firehose instability driven by excessive parallel temperature anisotropy, propagating in parallel direction with respect to the ambient magnetic field, except that the free energy source for the heat flux instability resides in the effective parallel pressure provided by the counter-streaming electrons.

  10. Auditory Risk of Exploding Hydrogen-Oxygen Balloons (United States)

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


    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…

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

    Directory of Open Access Journals (Sweden)

    Vanessa M.J. Lee


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

  12. 21 CFR 884.5050 - Metreurynter-balloon abortion system. (United States)


    ... 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...

  13. Evaluating shoulder instability treatment

    NARCIS (Netherlands)

    van der Linde, J.A.


    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

  14. Single-balloon versus double-balloon bipedicular kyphoplasty for osteoporotic vertebral compression fractures. (United States)

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


    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.

  15. Experiments with Helium-Filled Balloons (United States)

    Zable, Anthony C.


    The concepts of Newtonian mechanics, fluids, and ideal gas law physics are often treated as separate and isolated topics in the typical introductory college-level physics course, especially in the laboratory setting. To bridge these subjects, a simple experiment was developed that utilizes computer-based data acquisition sensors and a digital gram scale to estimate the molar mass of the gas in an inflated balloon. In this experiment, the comparable density of an inflated balloon to that of atmospheric air introduces a significant role for buoyancy that must be accounted for. The ideal gas law approximation is assumed for both the isolated gas mixture within the balloon and the surrounding air, which defines the relationship between the gas pressure, volume, temperature, and molar quantity. Analysis of the forces associated with the inflated balloon with the incorporation of Archimedes' principle and the ideal gas law into Newton's second law results in an experimental method for the measurement of the molar mass and mole fraction of a gas that is easy to implement yet academically challenging for students. The following narrative describes the basic setup of this experiment, along with a sample set of data as acquired and analyzed by a typical physics student from one of my classes.

  16. Pumpkins and onions and balloon design (United States)

    Winker, J. A.

    The reach for a capability to make long flights (months) with heavy payloads (tonnes) has long been pursued. The closest we have come is with polar flights devoid of a significant diurnal cycle. Superpressure technology, with its ability to survive diurnal cycles, is an obvious choice, but materials limitations have been an obstacle to realizing these ambitious goals. Now comes an assortment of new synthetic materials, coupled with a special variety of superpressure balloon which, in combination, is poised to yield a solution for our enhanced duration/payload quest. In this paper we are looking not at materials, but only at a balloon concept. This concept is a "natural shape" oblate spheroid balloon whose shape is chosen to exploit properties of component materials, particularly newly available ones. The current variation of this concept is called a "pumpkin" balloon. The most visible work on this shape is that done by France's CNES, Japan's ISAS, and in the USA by NASA's Wallops Flight Facility. But the basic design idea is not new; it extends back at least a half century. This paper traces the origins of the shape, its evolution through various iterations, and it speculates on some of the recent thinking regarding construction details.

  17. Stratospheric Balloon Platforms for Near Space Access (United States)

    Dewey, R. G.


    For over five decades, high altitude aerospace balloon platforms have provided a unique vantage point for space and geophysical research by exposing scientific instrument packages and experiments to space-like conditions above 99% of Earth's atmosphere. Reaching altitudes in excess of 30 km for durations ranging from hours to weeks, high altitude balloons offer longer flight durations than both traditional sounding rockets and emerging suborbital reusable launch vehicles. For instruments and experiments requiring access to high altitudes, engineered balloon systems provide a timely, responsive, flexible, and cost-effective vehicle for reaching near space conditions. Moreover, high altitude balloon platforms serve as an early means of testing and validating hardware bound for suborbital or orbital space without imposing space vehicle qualifications and certification requirements on hardware in development. From float altitudes above 30 km visible obscuration of the sky is greatly reduced and telescopes and other sensors function in an orbit-like environment, but in 1g. Down-facing sensors can take long-exposure atmospheric measurements and images of Earth's surface from oblique and nadir perspectives. Payload support subsystems such as telemetry equipment and command, control, and communication (C3) interfaces can also be tested and operationally verified in this space-analog environment. For scientific payloads requiring over-flight of specific areas of interests, such as an active volcano or forest region, advanced mission planning software allows flight trajectories to be accurately modeled. Using both line-of-sight and satellite-based communication systems, payloads can be tracked and controlled throughout the entire mission duration. Under NASA's Flight Opportunities Program, NSC can provide a range of high altitude flight options to support space and geophysical research: High Altitude Shuttle System (HASS) - A balloon-borne semi-autonomous glider carries

  18. 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


    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.

  19. Report on the Activities of National Balloon Facility, Hyderabad (United States)

    Vasudevan, Rajagopalan; Sreenivasan, S.; Suneel Kumar, B.; Kulkarni, P. M.


    More than five and half decades back, the Indian Balloon Group at Tata Institute of Fundamental Research, Mumbai started development of stratospheric zero pressure balloon technology and today it is one among the leading balloon groups in the world. For the past 40 years, the Institute has been operating a Scientific Balloon Facility at Hyderabad and carried out 478 balloon flights for various disciplines of space sciences like primary cosmic ray studies, X ray, Gamma Ray, Infra Red Astronomies and Atmospheric science maintaining 100% success rate during the past nine years. The Balloon Facility has the capability to build balloons of volume up to 750,000 Cu.M. as well as carrying out R & D in all aspects of scientific ballooning like balloon engineering, balloon material development, general and flight support instrumentation. A continued effort in R & D for ultra thin balloon material for High Altitude Sounding Flights has resulted in lowering the thickness of the proven indigenous Antrix film initially from 6 to 3.8 microns in the first phase and further reduction to 2.7 microns in the second phase. A test balloon of volume 5000 Cu.M. using the 2.7 micron film attained a record altitude of 45.0 Km. amsl with 1 Kg. GPS sonde payload. A 60,000 Cu.M. balloon fabricated out of 3.8 micron film capable of reaching 47 Km. Altitude with 10 Kg. Payload is awaiting trial. This report briefly describes our balloon activities during the past two years. In atmospheric sciences, aerosol studies were made with OPC,QCM,Aethelometer, Nephelometer,MWR, CIMEL Sun Photometer and Raman LIDAR.Measuments of vertical profile of Meteorological parameters and ozone upto stratosphere using GPS Radiosonde and Ozone sonde is made respectively.Study of Ionospheric tomography is done with CADI and CRABEX.

  20. Tearing mode instability due to anomalous resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Atsushi [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka (Japan); Itoh, Sanae I.; Yagi, Masatoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics


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

  1. Shoulder instability; Schulterinstabilitaeten

    Energy Technology Data Exchange (ETDEWEB)

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


    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.)

  2. Balloon-borne gamma-ray polarimetry

    CERN Document Server

    Pearce, Mark


    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.

  3. Burn Injury Arise From Flying Balloon Toys


    Yalcin Kulahci; Fatih Zor; Mehmet Bozkurt; Serdar Ozturk; Mustafa Sengezer


    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 balloon...

  4. 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


    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...

  5. MAXIS Balloon Observations of Electron Microburst Precipitation (United States)

    Millan, R. M.; Hunter, A. E.; McCarthy, M. P.; Lin, R. P.; Smith, D. M.


    Quantifying and understanding losses is an integral part of understanding relativistic electron variability in the radiation belts. SAMPEX observations indicate that electron microburst precipitation is a major loss mechanism during active periods; the loss of relativistic electrons during a six hour period due to microburst precipitation was recently estimated to be comparable to the total number of trapped electrons in the outer zone (Lorentzen et al., 2001). Microburst precipitation was first observed from a balloon (Anderson and Milton, 1964), but these early measurements were only sensitive to MAXIS 2000 long duration balloon campaign. MAXIS was launched from McMurdo Station in Antarctica carrying a germanium spectrometer, a BGO scintillator and two X-ray imagers designed to measure the bremsstrahlung produced by precipitating electrons. The balloon circumnavigated the south pole in 18 days covering magnetic latitudes ranging from 58o-90o South. During the week following a moderate geomagnetic storm (with Dst reaching -91 nT), MAXIS detected a total of over 16 hours of microburst precipitation. We present high resolution spectra obtained with the MAXIS germanium spectrometer which allow us to determine the precipitating electron energy distribution. The precipitating distribution will then be compared to the trapped distribution measured by the GPS and LANL satellites. We also examine the spatial distribution of the precipitation.

  6. Long Duration Balloon Charge Controller Stack Integration (United States)

    Clifford, Kyle

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

  7. Report on the Brazilian Scientific Balloon Program (United States)

    Braga, Joao


    We report on the recent scientific ballooning activities in Brazil, and present the plans for the next few years. Recent technological developments, especially on telecommunications and gondola attitude control systems will be reported. We also present the recent progress achieved in the development of the protoMIRAX balloon experiment. protoMIRAX is a balloon-borne hard X-ray imaging telescope under development at INPE as a pathfinder for the MIRAX (Monitor e Imageador de Raios X) satellite mission. The experiment consists essentially in a hard X-ray coded-aperture imager to operate in the 20-200 keV energy range. The detector plane is a square array of 196 10mm x 10mm x 2mm CdZnTe (CZT) planar detectors. A collimator defines a fully-coded field-of-view of 20 x 20 degrees, with 7 x 7 degrees of full sensitivity and an angular resolution of 1.7 degrees. We describe the final stages of development and testing of the front-end electronics, with charge preamplifiers, LNAs, shapers and Wilkinson-type ADCs customized for these detectors. We also show detailed Monte Carlo simulations of the flight background and the expected flight images of bright sources performed with the use of GEANT4.

  8. 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.

  9. Cavitation Instabilities in Inducers (United States)


    gas handling turbomachines . The fluctuation of the cavity length is plotted in Fig.8 under the surge mode oscillation vi . The major differences...Cavitation Instabilities of Turbomachines .” AIAA Journal of Propulsion and Power, Vol.17, No.3, 636-643. [5] Tsujimoto, Y., (2006), “Flow Instabilities in


    NARCIS (Netherlands)



    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

  11. 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)


    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.

  12. Double-balloon endoscopy: Who needs it?

    DEFF Research Database (Denmark)

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


    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 selectio...... within the next 12 months. Conclusions. CE can be applied as a screening procedure for DBE and allows for an approximately two-thirds reduction in the need for DBE as well as enabling a choice to be made between the oral and anal route Udgivelsesdato: 2008...

  13. Pneumothorax, music and balloons: A case series

    Directory of Open Access Journals (Sweden)

    Shiferaw Dejene


    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.

  14. Ballooning Spiders: The Case for Electrostatic Flight

    CERN Document Server

    Gorham, Peter W


    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.

  15. Thrombus aspiration catheter is a Dottering balloon. (United States)

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


    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?

  16. Flight Qualification of the NASA's Super Pressure Balloon (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

  17. Nonlinear helical MHD instability

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  18. 21 CFR 870.1350 - Catheter balloon repair kit. (United States)


    ... 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...

  19. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Praveen Vemula


    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.”

  1. 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


    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.

  2. An overview of instrumentation capabilities for Scientific ballooning in India (United States)

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


    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.

  3. Global kinetic ballooning mode simulations in BOUT++ (United States)

    Ma, C. H.; Xu, X. Q.


    We report on simulation results of a 3+1 gyro-Landau-fluid (GLF) model in BOUT++ framework, which contributes to increasing the physics understanding of the edge turbulence. We find that there is no second stability region of kinetic ballooning modes (KBM) in the concentric circular geometry. The first unstable β of KBM decreases below the ideal ballooning mode threshold with increasing {ηi} . In order to study the KBM in the real tokamak equilibrium, we find that the approximation of shifted circular geometry (β \\ll {{\\varepsilon}2} ) is not valid for a high β global equilibrium near the second stability region of KBM. Thus we generate a series of real equilibria from a global equilibrium solver CORSICA, including both Shafranov shift and elongation effects, but not including bootstrap current. In these real equilibria, the second stability region of KBM are observed in our global linear simulations. The most unstable mode for different β are the same while the mode number spectrum near the second stability region is wider than the case near the first stability region. The nonlinear simulations show that the energy loss of an ELM keeps increasing with β, because the linear drive of the turbulence remains strong for the case near the second stability region during profile evolution.

  4. A constitutive equation for stratospheric balloon materials (United States)

    Rand, J.; Sterling, J.

    The selection of a suitable material for use as a reliable stratospheric balloon gas barrier and structural component is based on a variety of desired properties. In order to achieve the required combination of weight per unit area, helium permeation, strength, flexibility and toughness at low temperatures, low density polyethylene has been used for the last half century. During the last decade, linear low density polyethylene (LLDPE) has been found to have even better properties for this application. Thin films extruded from this type resin have been found to have time dependent properties which should be understood in order to make an intelligent analysis of the balloon. This paper describes the current effort to characterize a 38 micron coextrusion of LLDPE as a nonlinearly viscoelastic material. The resulting constitutive equation may be used to accurately describe the time dependent creep and/or relaxation of this film when subjected to a biaxial state of stress. Recent laboratory data have been used to modify an existing model of LLDPE to account for differences caused by the coextrusion process. The new model will facilitate structure design optimization and reliability assessment, and may further be utilized as a predictive tool to benefit in-flight operations. Unfortunately, current structural analysis techniques based on linear elastic properties will predict stresses in excess of those which actually exist. An example will be presented which demonstrates the magnitude of this error when nonlinear behavior is ignored.

  5. EUSO-Balloon: The first flight (United States)

    Scotti, Valentina; Osteria, Giuseppe


    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.

  6. EUSO-Balloon: The first flight

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, Valentina, E-mail:; Osteria, Giuseppe


    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.

  7. Spondylolisthesis and Posterior Instability

    Energy Technology Data Exchange (ETDEWEB)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D. (Privatpraxis fuer Upright MRT, Koeln (Germany)); Simons, P.; Kuchta, J. (Media Park Klinik, Koeln (Germany))


    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.


    NARCIS (Netherlands)



    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

  9. Instabilities in nuclei

    CERN Document Server

    Csernai, László P; Papp, G


    The evolution of dynamical perturbations is examined in nuclear multifragmentation in the frame of Vlasov equation. Both plane wave and bubble type of perturbations are investigated in the presence of surface (Yukawa) forces. An energy condition is given for the allowed type of instabilities and the time scale of the exponential growth of the instabilities is calculated. The results are compared to the mechanical spinodal region predictions. PACS: 25.70 Mn

  10. Prediction of Algebraic Instabilities (United States)

    Zaretzky, Paula; King, Kristina; Hill, Nicole; Keithley, Kimberlee; Barlow, Nathaniel; Weinstein, Steven; Cromer, Michael


    A widely unexplored type of hydrodynamic instability is examined - large-time algebraic growth. Such growth occurs on the threshold of (exponentially) neutral stability. A new methodology is provided for predicting the algebraic growth rate of an initial disturbance, when applied to the governing differential equation (or dispersion relation) describing wave propagation in dispersive media. Several types of algebraic instabilities are explored in the context of both linear and nonlinear waves.

  11. Identifying Instability Pockets (United States)


    TYPE SAMS Monograph 3. DATES COVERED (From - To) FEB 2014 – DEC 2014 4. TITLE AND SUBTITLE IDENTIFYING INSTABILITY POCKETS 5a. CONTRACT...century, and if the first few years of the new century are indicative of the future, Central Asia is surely destined to be a focus of the world...reasons. First, there is a possibility of the collapse and instability of Afghanistan once all the U.S troops vacate .107 This stability will most

  12. Effect of intra-aortic balloon pump on coronary blood flow during different balloon cycles support: A computer study. (United States)

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


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

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

    Energy Technology Data Exchange (ETDEWEB)

    S.R. Hudson; C.C. Hegna


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

  14. Propagating Instabilities in Solids (United States)

    Kyriakides, Stelios


    Instability is one of the factors which limit the extent to which solids can be loaded or deformed and plays a pivotal role in the design of many structures. Such instabilities often result in localized deformation which precipitates catastrophic failure. Some materials have the capacity to recover their stiffness following a certain amount of localized deformation. This local recovery in stiffness arrests further local deformation and spreading of the instability to neighboring material becomes preferred. Under displacement controlled loading the propagation of the transition fronts can be achieved in a steady-state manner at a constant stress level known as the propagation stress. The stresses in the transition fronts joining the highly deformed zone to the intact material overcome the instability nucleation stresses and, as a result, the propagation stress is usually much lower than the stress required to nucleate the instability. The classical example of this class of material instabilities is L/"uders bands which tend to affect mild steels and other metals. Recent work has demonstrated that propagating instabilities occur in several other materials. Experimental and analytical results from four examples will be used to illustrate this point: First the evolution of L=FCders bands in mild steel strips will be revisited. The second example involves the evolution of stress induced phase transformations (austenite to martensite phases and the reverse) in a shape memory alloy under displacement controlled stretching. The third example is the crushing behavior of cellular materials such as honeycombs and foams made from metals and polymers. The fourth example involves the axial broadening/propagation of kink bands in aligned fiber/matrix composites under compression. The microstructure and, as a result, the micromechanisms governing the onset, localization, local arrest and propagation of instabilities in each of the four materials are vastly different. Despite this

  15. Design and Calibrations of the Protomirax Balloon Telescope and the Brazilian Scientific Balloon Program (United States)

    Braga, Joao; D'Amico, Flavio; Avila, Manuel


    In this presentation we report on the recent scientific ballooning activities in Brazil, including important international collaborations, and present our plan for the next few years. We also present the recent progress achieved in the design of the detector system of the protoMIRAX balloon experiment and report on the scientific balloon activities in Brazil. protoMIRAX is a balloon-borne X-ray imaging telescope under development at INPE as a pathfinder for the MIRAX (Monitor e Imageador de Raios X) satellite mission. The experiment consists essentially in an X-ray (30-200 keV) coded-aperture imager which employs a square array of 196 10mm x 10mm x 2mm CdZnTe (CZT) planar detectors made by eV Products in the USA. A collimator defines a fully-coded field-of-view of 20o x 20o, with 4o x 4o of full sensitivity. The final angular resolution will depend on the mask pattern used. In this paper we describe the design and development of the detector plane, including the front-end electronics. Preamplifiers and shaping amplifiers, customized for these detectors, were designed and built at INPE. Laboratory spectral measurements show an energy resolution of 12.0% at 60 keV, of which 10.6% is due to intrinsic electronics noise measured with a pulser at similar pulse height levels. We present spectral results obtained in the laboratory as well as initial calibration results of the acquisition system designed to get positions and energies in the detector plane. We show simulations of the coded-aperture images with different mask designs and iterative reconstruction methods.

  16. Balloon observations of spatial coherence in the Global Circuit (United States)

    Holzworth, R. H.; Polar Patrol Balloon Team

    The first campaign of the Polar Patrol Balloon (PPB) experiment (1st-PPB) was carried out at Syowa Station in Antarctica during 1990-1991 and 1992-1993. Based on the results of the 1st-PPB experiment, the next campaign (2nd-PPB) was carried out in the austral summer of 2002-2003. This paper will present the global circuit results from the 2nd-PPB experiment. In that experiment, three balloons were launched for the purpose of upper atmosphere physics observation (3 balloons). Payloads of these 3 flights were identical with each other, and were launched as close together in time as allowed by weather conditions to constitute a cluster of balloons during their flights. Such a "Balloon Cluster" is suitable to observe temporal evolution and spatial distribution of phenomena in the ionospheric regions and boundaries that the balloons traversed during their circumpolar trajectory. More than 20 days of simultaneous fair weather 3-axis electric field and stratospheric conductivity data were obtained at geomagnetic latitudes ranging from sub-auroral to the polar cap. Balloon separation varied from ˜ 60 to ˜ 500 km. This paper will present the global circuit observations with emphasis on the times of apparent spatial variation in the vertical fair weather field.

  17. Geodesic Acoustic Propagation and Ballooning Mode Formalism (United States)

    Li, M. B.; Diamond, P. H.; Young, G. G.; Arakawa, M.


    Relevance of ballooning formalism (BMF) in nonlinear interaction of toroidal electromagnetic drift waves in the presence of zonal flows and Geodesic Acoustic Oscillation (GAO) is critically examined from a physical argument of radial propagation of wave packets. To achieve the quasi-translational invariance of poloidal harmonics which is necessary for the BMF, the geodesic curvature induced transfer [1] of fluctuation energy in radial direction should occur faster than the time scale of physical interest. Of course, this does not happen necessarily in drift-Alfven (DALF) turbulence simulations [2]. This observation casts considerable doubts on the applicability of various codes based on the BMF concept to nonlinear electromagnetic problems. [1] B. Scott, Phys. Letters A 320 (2003) 53. [2] B. Scott, New J. Phys 7 (2005) 92.

  18. The Norwegian Sounding Rocket and Balloon Program (United States)

    Skatteboe, Rolf


    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.

  19. Intragastric balloon: ethics, medical need and cosmetics. (United States)

    Kotzampassi, Katerina; Shrewsbury, Anne D


    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'.

  20. Results of the first EUSO-Balloon flight (United States)

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


    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.

  1. Balloon dilation of congenital supravalvular pulmonic stenosis in a dog (United States)

    Treseder, Julia R.


    Percutaneous balloon valvuloplasty is considered the standard of care for treatment of valvular pulmonic stenosis, a common congenital defect in dogs. Supravalvular pulmonic stenosis is a rare form of pulmonic stenosis in dogs and standard treatment has not been established. Although, there have been reports of successful treatment of supravalvular pulmonic stenosis with surgical and stenting techniques, there have been no reports of balloon dilation to treat dogs with this condition. Here, a case of supravalvular pulmonic stenosis diagnosed echocardiographically and angiographically in which a significant reduction in pressure gradient was achieved with balloon dilation alone is presented. PMID:27297421

  2. An investigation of electrostatically deposited radionuclides on latex balloons

    Energy Technology Data Exchange (ETDEWEB)

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


    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)

  3. 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)


    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.)

  4. Immediate Outcome of Balloon Mitral Valvuloplasty with JOMIVA Balloon during Pregnancy (United States)

    Ramasamy, Ramona; Kaliappan, Tamilarasu; Gopalan, Rajendiran; Palanimuthu, Ramasmy; Anandhan, Premkrishna


    Introduction Rheumatic mitral stenosis is the most common Valvular Heart Disease encountered during pregnancy. Balloon Mitral Valvuloplasty (BMV) is one of the treatment option available if the symptoms are refractory to the medical management and the valve anatomy is suitable for balloon dilatation. BMV with Inoue balloon is the most common technique being followed worldwide. Over the wire BMV is a modified technique using Joseph Mitral Valvuloplasty (JOMIVA) balloon catheter which is being followed in certain centres. Aim To assess the immediate post procedure outcome of over the wire BMV with JOMIVA balloon. Materials and Methods Clinical and echocardiographic parameters of pregnant women with significant mitral stenosis who underwent elective BMV with JOMIVA balloon in our institute from 2005 to 2015 were analysed retrospectively. Severity of breathlessness (New York Heart Association Functional Class), and duration of pregnancy was included in the analysis. Pre procedural echocardiographic parameters which included severity of mitral stenosis and Wilkin’s scoring were analysed. Clinical, haemodynamic and echocardiographic outcomes immediately after the procedure were analysed. Results Among the patients who underwent BMV in our Institute 38 were pregnant women. Twenty four patients (63%) were in New York Heart Association (NYHA) Class III. All of them were in sinus rhythm except two (5%) who had atrial fibrillation. Thirty four patients (89.5%) were in second trimester of pregnancy at the time of presentation and four (10.5%) were in third trimester. Echocardiographic analysis of the mitral valve showed that the mean Wilkin’s score was 7.3. Mean mitral valve area pre procedure was 0.8 cm2. Mean gradient across the valve was 18 mmHg. Ten patients (26.5%) had mild mitral regurgitation and none had more than mild mitral regurgitation. Thirty six patients had pulmonary hypertension as assessed by tricuspid regurgitation jet velocity. All of them underwent BMV

  5. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    Vishnu M Bannur


    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.

  6. Causes of genome instability

    DEFF Research Database (Denmark)

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


    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...... function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make......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...

  7. Mixing through shear instabilities

    CERN Document Server

    Brüggen, M


    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.

  8. 10 meter Sub-Orbital Large Balloon Reflector (LBR) Project (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...

  9. Ohmic scaling based on current diffusive ballooning mode

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masatoshi; Itoh, Sanae [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Fukuyama, Atsushi; Itoh, Kimitaka


    Based on the anomalous transport model due to current diffusive ballooning mode turbulence, the global energy confinement time in a tokamak with Ohmic heating is theoretically studied. Relations to empirical scaling laws are also discussed. (author)

  10. Design Evolution and Methodology for Pumpkin Super-Pressure Balloons (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. Low Cost Variable Conductance Heat Pipe for Balloon Payload Project (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...

  12. Balloon Pump with Floating Valves for Portable Liquid Delivery

    Directory of Open Access Journals (Sweden)

    Yuya Morimoto


    Full Text Available In this paper, we propose a balloon pump with floating valves to control the discharge flow rates of sample solutions. Because the floating valves were made from a photoreactive resin, the shapes of the floating valves could be controlled by employing different exposure patterns without any change in the pump configurations. Owing to the simple preparation process of the pump, we succeeded in changing the discharge flow rates in accordance with the number and length of the floating valves. Because our methods could be used to easily prepare balloon pumps with arbitrary discharge properties, we achieved several microfluidic operations by the integration of the balloon pumps with microfluidic devices. Therefore, we believe that the balloon pump with floating valves will be a useful driving component for portable microfluidic systems.

  13. The Hubble party balloon and the expanding universe (United States)

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


    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.

  14. Small Research Balloons in a Physics Course for Education Majors (United States)

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


    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

  15. Analysis of current diffusive ballooning mode in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Morihisa [Faculty of Engineering, Okayama University, Okayama (Japan); Fukuyama, Atsushi [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan); Itoh, Sanae-I.; Yagi, Masatoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics


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

  16. Intrauterine tamponade balloon use in the treatment of uterine inversion


    Haeri, Sina; Rais, Sheliza; Monks, Brian


    Uterine inversion is a rare but life-threatening obstetrical emergency that occurs when the fundus of the uterus prolapses through the cervix, hence turning the uterus inside out. In this case report, we present our experience using an intrauterine tamponade balloon for management of uterine inversion, and a review of the literature. The utility of an intrauterine tamponade balloon in cases of uterine inversion, especially when maternal medical conditions preclude the use of uterotonics, or r...

  17. Introduction (Special Issue on Scientific Balloon Capabilities and Instrumentation) (United States)

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


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

  18. Development of a tiny tandem balloon system for atmospheric observation (United States)

    Saito, Yoshitaka; Yamada, Kazuhiko; Fujiwara, Masatomo


    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.

  19. Catching Comet's Particles in the Earth's Atmosphere by Using Balloons (United States)

    Potashko, Oleksandr; Viso, Michel

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

  20. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. Benestent Study Group.


    Serruys, P.W.; de Jaegere, P; Kiemeneij, F.; Macaya, C; Rutsch, W; Heyndrickx, G.; Emanuelsson, H.; Marco, J.; Legrand, Victor; Materne, P.


    BACKGROUND: 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 outcomes as compared with standard balloon angioplasty. METHODS: A total of 520 patients with stable angina and a single coronary-artery lesion were randomly assigned to either stent implantation (262 patients)...

  1. Shock instability in dissipative gases


    Radulescu, Matei I.; Sirmas, Nick


    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 ...

  2. Burn Injury Arise From Flying Balloon Toys

    Directory of Open Access Journals (Sweden)

    Yalcin Kulahci


    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

  3. Balloon borne arcsecond pointer feasibility study (United States)

    Ward, Philip R.; Deweese, Keith D.


    A major hurdle in extending the range of experiments for which balloon vehicles are useful has been the imposition of the gondola dynamics on the accuracy with which an instrument can be kept pointed at a celestial target. In this paper, the foundation for a high fidelity controller simulation is presented and it is shown that sub-arcsecond pointing stability can be achieved for a large instrument pointing at an inertial target. The flexibility of the flight train is represented through generalized modal analysis. A multiple controller scheme is introduced with a coarse azimuth pointer and a pitch-yaw gimbal mount for fine pointing. An analysis and demonstration of the necessity in eliminating static friction are provided along with a solution to eliminate static friction from the system dynamics. A control scheme involving linear accelerometers for enhanced disturbance rejection is also presented. This paper establishes that the proposed control strategy can be made robustly stable with significant design margins. Also demonstrated is the efficacy of the proposed system in rejecting disturbances larger than those considered realistic.

  4. Percutaneous balloon valvuloplasty in mitral stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyung; Oh, Byung Hee; Park, Kyung Ju; Kim, Seung Hyup; Lee, Young Woo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)


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

  5. Burn Injury Arise From Flying Balloon Toys

    Directory of Open Access Journals (Sweden)

    Yalcin Kulahci


    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. Optical coherence tomography monitoring of angioplasty balloon inflation in a deployment tester (United States)

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


    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.

  7. Intragastric balloon followed by diet vs intragastric balloon followed by another balloon: a prospective study on 100 patients. (United States)

    Genco, Alfredo; Cipriano, Massimiliano; Bacci, Vincenzo; Maselli, Roberta; Paone, Emanuela; Lorenzo, Michele; Basso, Nicola


    Aim of this study is to compare the efficacy of BioEnterics Intragastric Balloon (BIB®) followed by diet with BIB followed by another BIB. A prospective study was designed: a homogeneous group of 100 obese patients (age range 25-35, BMI range 40.0-44.9, M/F ratio 1/4) was allocated into two groups according to procedure: BIB (6 months) followed by diet therapy (7 months; group A = 50 pts), BIB positioning followed by another BIB after 1 month (group B = 50 pts). Baseline demographics were similar in both groups (Group A 10M/40F; mean age 31.4 ± 2.6; range 25-35; mean weight 106.3 ± 12.5 Kg; range 88-150; mean BMI 42.6±2.7 Kg/m(2); range 40.2-43.8; Group B 10M/40F; mean age 32.1 ± 2.1; range 25-35; mean weight 107.1 ± 11.9 Kg; range 90-150; mean BMI 42.9 ± 2.3; range 40.2-43.9). In both groups, weight loss parameters (Kg, BMI, and % EBL) were considered. Statistics were by Fisher's exact test (p < 0.05 was considered significant). At the time of 1st BIB removal, weight loss parameters in both groups were not significantly different: Group A: mean weight was 83.7±19.1 (range 52-151); mean BMI 34.2 ± 3.9 (range 32.4-43.8); and mean %EBL 43.5 ± 21.1 (range 0-68). Group B: mean weight was 84.9 ± 18.3 (range 50-148); mean BMI 34.8 ± 3.3 (range 32.4-43.8); and mean % EBL 45.2 ± 22.5% (range 0-68). At the study end, weight loss parameters were significantly lower in patients who underwent consecutive BIB (p < 0.05): mean BMI was 30.9 ± 7.2 Kg/m(2) (range 24-40), and 35.9 ± 9.7 Kg/m(2) (range 34-42); mean % EBL was 51.9 ± 24.6% (range 0-100) and 25.1 ± 26.2% (range 0-100) in group B and A, respectively. As compared with diet, a second intragastric balloon can be positioned without difficulties, achieving good results with continuous weight loss.

  8. Extradural balloon obliteration of the empty sella report of three cases (intrasellar balloon obliteration). (United States)

    Gazioğlu, N; Akar, Z; Ak, H; Işlak, C; Koçer, N; Seçkin, M S; Kuday, C


    Empty sella syndrome is an anatomical and clinical entity composed of intrasellar reposition of the CSF and compression of the pituitary tissue, resulting in a clinical picture of headache, visual field defect, CSF rhinorrhea and some mild endocrinological disturbances. While some cases are primary with no appreciable aetiology, secondary cases are associated with prior operation or radiotherapy of the region. In our series, 3 patients with primary empty sella syndrome were treated by the current approach of extradural filling of the sellar cavity. This technique was first described by Guiot and widely accepted thereafter. We used a detachable silicon balloon filled with HEMA or liquid silicone for obliteration of the sellar cavity and obtained clinically satisfactory results without complications. Visual symptoms regressed and headache disappeared. But at long term follow-up all the balloons were found to be deflated. Despite the facility and efficacy of the technique we do not recommend it in the treatment of the empty sella because the filling of the sella is only transient and relapses may occur.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Min; Lee, Sang Hoon; Han, Young Min; Chung, Gyung Ho; Kim, Chong Soo; Choi, Ki Chul [Chung Ang University College of Medicine, Seoul (Korea, Republic of); Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)


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

  10. Coolability of ballooned VVER bundles with pellet relocation

    Energy Technology Data Exchange (ETDEWEB)

    Hozer, Z.; Nagy, I.; Windberg, P.; Vimi, A. [AEKI, 49, Budapest, H-1525 (Hungary)


    During a LOCA incident the high pressure in the fuel rods can lead to clad ballooning and the debris of fuel pellets can fill the enlarged volume. The evaluation of the role of these two effects on the coolability of VVER type fuel bundles was the main objective of the experimental series. The tests were carried out in the modified configuration of the CODEX facility. 19-rod electrically heated VVER type bundle was used. The test section was heated up to 600 deg. C in steam atmosphere and the bundle was quenched from the bottom by cold water. Three series of tests were performed: 1. Reference bundle with fuel rods without ballooning, with uniform power profile. 2. Bundle with 86% blockage rate and with uniform power profile. The blockage rate was reached by superimposing hollow sleeves on all 19 fuel rods. 3. Bundle with 86% blockage rate and with local power peak in the ballooned area. The local power peak was produced by the local reduction the cross section of the internal heater bar inside of the fuel rods. In all three bundle configurations three different cooling water flow-rates were applied. The experimental results confirmed that a VVER bundle with even 86% blockage rate remains coolable after a LOCA event. The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods. Earlier tests on the coolability of ballooned bundles were performed only with Western type bundles with square fuel lattice. The present test series was the first confirmation of the coolability of VVER type bundles with triangular lattice. The accumulation of fuel pellet debris in the ballooned volume results in a local power peak, which leads to further slowing down of quench front. The first tests indicated that the effect of local power peak was less significant on the delay of cooling down than the effect of ballooning. (authors)

  11. The University of Alberta High Altitude Balloon Program (United States)

    Johnson, W.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Mann, I. R.; Mazzino, L.; Rae, J.; University of Alberta High Altitude Balloon Team


    The University of Alberta High Altitude Balloon (UA-HAB) program is a one and half year program sponsored by the Canadian Space Agency (CSA) that offers hands on experience for undergraduate and graduate students in the design, build, test and flight of an experimental payload on a high altitude balloon platform. Utilising low cost weather balloon platforms, and through utilisation of the CSA David Florida Laboratory for thermal-vacuum tests , in advance of the final flight of the payload on a NASA high altitude balloon platform. Collectively the program provided unique opportunities for students to experience mission phases which parallel those of a space satellite mission. The program has facilitated several weather balloon missions, which additionally provide educational opportunities for university students and staff, as well as outreach opportunities among junior and senior high school students. Weather balloon missions provide a cheap and quick alternative to suborbital missions; they can be used to test components for more expensive missions, as well as to host student based projects from different disciplines such as Earth and Atmospheric Sciences (EAS), Physics, and Engineering. In addition to extensive skills development, the program aims to promote recruitment of graduate and undergraduate students into careers in space science and engineering. Results from the UA-HAB program and the flight of the UA-HAB shielded Gieger counter payload for cosmic ray and space radiation studies will be presented. Lessons learned from developing and maintaining a weather balloon program will also be discussed. This project is undertaken in partnership with the High Altitude Student Platform, organized by Louisiana State University and the Louisiana Space Consortium (LaSpace), and sponsored by NASA, with the financial support of the Canadian Space Agency.

  12. Development of a super-pressure balloon with a diamond-shaped net --- result of a ground inflation test of a 2,000 cubic-meter balloon --- (United States)

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


    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.

  13. Genetic instability in Gynecological Cancer

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qing-hua; ZHOU Hong-lin


    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.

  14. Modulation instability: The beginning (United States)

    Noskov, Roman; Belov, Pavel; Kivshar, Yuri


    The study of metal nanoparticles plays a central role in the emerging novel technologies employing optics beyond the diffraction limit. Combining strong surface plasmon resonances, high intrinsic nonlinearities and deeply subwavelength scales, arrays of metal nanoparticles offer a unique playground to develop novel concepts for light manipulation at the nanoscale. Here we suggest a novel principle to control localized optical energy in chains of nonlinear subwavelength metal nanoparticles based on the fundamental nonlinear phenomenon of modulation instability. In particular, we demonstrate that modulation instability can lead to the formation of long-lived standing and moving nonlinear localized modes of several distinct types such as bright and dark solitons, oscillons, and domain walls. We analyze the properties of these nonlinear localized modes and reveal different scenarios of their dynamics including transformation of one type of mode to another. We believe this work paves a way towards the development of nonlinear nanophotonics circuitry.

  15. Instabilities in sensory processes (United States)

    Balakrishnan, J.


    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.

  16. Instability and internet design

    Directory of Open Access Journals (Sweden)

    Sandra Braman


    Full Text Available Instability - unpredictable but constant change in one’s environment and the means with which one deals with it - has replaced convergence as the focal problem for telecommunications policy in general and internet policy in particular. Those who designed what we now call the internet during the first decade of the effort (1969-1979, who in essence served simultaneously as its policy-makers, developed techniques for coping with instability of value for network designers today and for those involved with any kind of large-scale sociotechnical infrastructure. Analysis of the technical document series that was medium for and record of that design process reveals coping techniques that began with defining the problem and went on to include conceptual labour, social practices, and technical approaches.

  17. Modulation instability: The beginning (United States)

    Zakharov, V. E.; Ostrovsky, L. A.


    We discuss the early history of an important field of “sturm and drang” in modern theory of nonlinear waves. It is demonstrated how scientific demand resulted in independent and almost simultaneous publications by many different authors on modulation instability, a phenomenon resulting in a variety of nonlinear processes such as envelope solitons, envelope shocks, freak waves, etc. Examples from water wave hydrodynamics, electrodynamics, nonlinear optics, and convection theory are given.

  18. The instability of markets

    CERN Document Server

    Huberman, B A; Huberman, Bernardo A; Youssefmir, Michael


    Recent developments in the global liberalization of equity and currency markets, coupled to advances in trading technologies, are making markets increasingly interdependent. This increased fluidity raises questions about the stability of the international financial system. In this paper, we show that as couplings between stable markets grow, the likelihood of instabilities is increased, leading to a loss of general equilibrium as the system becomes increasingly large and diverse.

  19. Carpal instability nondissociative. (United States)

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


    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.

  20. Chromosomal instability in meningiomas. (United States)

    van Tilborg, Angela A G; Al Allak, Bushra; Velthuizen, Sandra C J M; de Vries, Annie; Kros, Johan M; Avezaat, Cees J J; de Klein, Annelies; Beverloo, H Berna; Zwarthoff, Ellen C


    Approximately 60% of sporadic meningiomas are caused by inactivation of the NF2 tumor suppressor gene on chromosome 22. No causative gene is known for the remaining 40%. Cytogenetic analysis shows that meningiomas caused by inactivation of the NF2 gene can be divided into tumors that show monosomy 22 as the sole abnormality and tumors with a more complex karyotype. Meningiomas not caused by the NF2 gene usually have a diploid karyotype. Here we report that, besides the clonal chromosomal aberrations, the chromosome numbers in many meningiomas varied from one metaphase spread to the other, a feature that is indicative of chromosomal instability. Unexpectedly and regardless of genotype, a subgroup of tumors was observed with an average number of 44.9 chromosomes and little variation in the number of chromosomes per metaphase spread. In addition, a second subgroup was recognized with a hyperdiploid number of chromosomes (average 48.5) and considerable variation in numbers per metaphase. However, this numerical instability resulted in a clonal karyotype with chromosomal gains and losses in addition to loss of chromosome 22 only in meningiomas caused by inactivation of the NF2 gene. In cultured cells of all tumor groups, bi- and multinucleated cells were seen, as well as anaphase bridges, residual chromatid strings, multiple spindle poles, and unseparated chromatids, suggesting defects in the mitotic apparatus or kinetochore. Thus, we conclude that even a benign and slow-growing tumor like a meningioma displays chromosomal instability.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  2. Complexity Analysis of Balloon Drawing for Rooted Trees

    CERN Document Server

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


    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...

  3. Time-dependent strains and stresses in a pumpkin balloon (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

  4. Ballooning osteolysis in 71 failed total ankle arthroplasties. (United States)

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


    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.

  5. 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


    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.

  6. Stratospheric balloons from Esrange - current and future capabilities (United States)

    Norberg, O.

    Stratospheric balloon operations have been carried out at the Swedish Space Corporation's rocket, balloon and satellite operations base Esrange since 1974; approximately 550 stratospheric balloons have been launched during this period. The facility, located in northern Sweden at 68 degrees north, is fully equipped with a large launch pad, payload and flight train preparation hangars, telemetry stations, recovery helicopters, and supporting infrastructure. Many of the scientific balloons launched are CNES missions. This paper will present the possibilities for scientific and technical balloon missions at high latitudes and with a vast landing area in northern Sweden, Finland, and Russia. The proximity to the Arctic polar vortex makes Esrange an ideal base for studies of for example the ozone destruction process in the Arctic. A new option proposed by the Swedish Space Corporation and NASA is to perform week-long missions from the south of Sweden to western Canada. A newly developed line-of-sight telemetry system, E-LINK, for high bit-rates (> 2 Mbps both downlink and uplink) and based on the Ethernet communication standard is also described.

  7. Ideal ballooning modes, shear flow and the stable continuum (United States)

    Taylor, J. B.


    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.

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

    CERN Document Server

    Taylor, J B


    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.

  9. Iridium: Global OTH data communications for high altitude scientific ballooning (United States)

    Denney, A.

    While the scientific community is no stranger to embracing commercially available technologies, the growth and availability of truly affordable cutting edge technologies is opening the door to an entirely new means of global communications. For many years high altitude ballooning has provided science an alternative to costly satellite based experimental platforms. As with any project, evolution becomes an integral part of development. Specifically in the NSBF ballooning program, where flight durations have evolved from the earlier days of hours to several weeks and plans are underway to provide missions up to 100 days. Addressing increased flight durations, the harsh operational environment, along with cumbersome and outdated systems used on existing systems, such as the balloon vehicles Support Instrumentation Package (SIP) and ground-based systems, a new Over-The-Horizon (OTH) communications medium is sought. Current OTH equipment planning to be phased-out include: HF commanding systems, ARGOS PTT telemetry downlinks and INMARSAT data terminals. Other aspects up for review in addition to the SIP to utilize this communications medium include pathfinder balloon platforms - thereby, adding commanding abilities and increased data rates, plus providing a package for ultra-small experiments to ride aloft. Existing communication systems employed by the National Scientific Balloon Facility ballooning program have been limited not only by increased cost, slow data rates and "special government use only" services such as TDRSS (Tracking and Data Relay Satellite System), but have had to make special provisions to geographical flight location. Development of the Support Instrumentation Packages whether LDB (Long Duration Balloon), ULDB (Ultra Long Duration Balloon) or conventional ballooning have been plagued by non-standard systems configurations requiring additional support equipment for different regions and missions along with a myriad of backup for redundancy. Several

  10. To sail the skies of Mars - Scientific ballooning on the red planet (United States)

    Gaidos, Eric J.; Burke, James D.


    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.

  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


    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. Matrix metalloproteinase inhibition reduces adventitial thickening and collagen accumulation following balloon dilation

    NARCIS (Netherlands)

    Sierevogel, MJ; Velema, E; van der Meer, FJ; Nijhuis, MO; de Kleijn, DPV; Borst, C; Pasterkamp, G


    Objective: Constrictive arterial remodeling following balloon angioplasty has been related to adventitial collagen accumulation and subsequent thickening and can be prevented by matrix ructalloprotemase (MMP) inhibition. Following balloon dilation, we examined the effect of MMP inhibition on colla-e

  13. Radiation Induced Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F.


    Radiation induced genomic instability can be observed in the progeny of irradiated cells multiple generations after irradiation of parental cells. The phenotype is well established both in vivo (Morgan 2003) and in vitro (Morgan 2003), and may be critical in radiation carcinogenesis (Little 2000, Huang et al. 2003). Instability can be induced by both the deposition of energy in irradiated cells as well as by signals transmitted by irradiated (targeted) cells to non-irradiated (non-targeted) cells (Kadhim et al. 1992, Lorimore et al. 1998). Thus both targeted and non-targeted cells can pass on the legacy of radiation to their progeny. However the radiation induced events and cellular processes that respond to both targeted and non-targeted radiation effects that lead to the unstable phenotype remain elusive. The cell system we have used to study radiation induced genomic instability utilizes human hamster GM10115 cells. These cells have a single copy of human chromosome 4 in a background of hamster chromosomes. Instability is evaluated in the clonal progeny of irradiated cells and a clone is considered unstable if it contains three or more metaphase sub-populations involving unique rearrangements of the human chromosome (Marder and Morgan 1993). Many of these unstable clones have been maintained in culture for many years and have been extensively characterized. As initially described by Clutton et al., (Clutton et al. 1996) many of our unstable clones exhibit persistently elevated levels of reactive oxygen species (Limoli et al. 2003), which appear to be due dysfunctional mitochondria (Kim et al. 2006, Kim et al. 2006). Interestingly, but perhaps not surprisingly, our unstable clones do not demonstrate a “mutator phenotype” (Limoli et al. 1997), but they do continue to rearrange their genomes for many years. The limiting factor with this system is the target – the human chromosome. While some clones demonstrate amplification of this chromosome and thus lend

  14. Evolution of NASA Scientific Ballooning and Particle Astrophysics Research (United States)

    Jones, William Vernon


    Particle astrophysics research has a history in ballooning that spans over 100 years, ever since Victor Hess discovered cosmic rays on a manned balloon in 1912. The NASA Particle Astrophysics Program currently covers the origin, acceleration and transport of Galactic cosmic rays, plus the Nature of Dark Matter and Ultrahigh Energy Neutrinos. Progress in each of these topics has come from sophisticated instrumentation flown on Long Duration Balloon (LDB) flights around Antarctica for more than two decades. Super Pressure Balloons (SPB) and International Space Station (ISS) platforms are emerging opportunities that promise major steps forward for these and other objectives. NASA has continued development and qualification flights leading to SPB flights capable of supporting 1000 kg science instruments to 33 km for upwards of hundred day missions, with plans for increasing the altitude to 38 km. This goal is even more important now, in view of the Astro2010 Decadal Study recommendation that NASA should support Ultra-Long Duration Balloon (ULDB) flight development for studies of particle astrophysics, cosmology and indirect detection of dark matter. The mid-latitude test flight of an 18.8 MCF SPB launched from Wanaka, NZ in 2015 achieved 32 days of nearly constant altitude exposure, and an identical SPB launched from Wanaka in 2016 with a science payload flew for 46 days. Scientific ballooning as a vital infrastructure component for cosmic ray and general astrophysics investigations, including training for young scientists, graduate and undergraduate students, leading up to the 2020 Decadal Study and beyond, will be presented and discussed.

  15. Near Space Lab-Rat Experimentation using Stratospheric Balloon (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


    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.

  16. Paclitaxel-coated balloons - Survey of preclinical data. (United States)

    Schnorr, B; Kelsch, B; Cremers, B; Clever, Y P; Speck, U; Scheller, B


    Restenosis following interventions in the coronary or peripheral arteries develops over weeks to months. In coronary arteries the restenosis rate has been markedly reduced since the advent of drug-eluting stents. Non-stent-based methods for local drug delivery enable restenosis inhibition without the need for stent implantation, does not permanently change the structure of the vessel, are repeatable, and seems to be applicable where drug-eluting stents provide insufficient protection. Preclinical data indicate that short exposure of the vessel wall to a lipophilic inhibitor of cell proliferation is sufficient for preventing restenosis. Initial evidence to this effect emerged from an investigation of paclitaxel embedded in a matrix that enhances the solubility and release of the agent from the balloon coating as well as its transfer to the vessel wall. Further corroborating data from preclinical and clinical studies demonstrating a reduction in late lumen loss and lower restenosis rates led to the market introduction of a variety of paclitaxel-coated angioplasty balloons. The effectiveness of restenosis inhibition is not determined by the active agent alone. Other factors that are crucial for the effectiveness and safety of drug-coated angioplasty balloons are the formulation containing the agent and the coating technique. In this review we first outline the development of paclitaxel-coated balloons to then provide an overview of the preclinical results obtained with different paclitaxel-coated balloons and finally compare these with the outcome in patients. The article concludes with a short outlook on initial results with a zotarolimus-coated angioplasty balloon.

  17. Second-generation endometrial ablation technologies: the hot liquid balloons. (United States)

    Vilos, George A; Edris, Fawaz


    Hysteroscopic endometrial ablation (HEA) was introduced in the 1980s to treat menorrhagia. Its use required additional training, surgical expertise and specialized equipment to minimize emergent complications such as uterine perforations, thermal injuries and excessive fluid absorption. To overcome these difficulties and concerns, thermal balloon endometrial ablation (TBEA) was introduced in the 1990s. Four hot liquid balloons have been introduced into clinical practice. All systems consist of a catheter (4-10mm diameter), a silicone balloon and a control unit. Liquids used to inflate the balloons include internally heated dextrose in water (ThermaChoice, 87 degrees C), and externally heated glycine (Cavaterm, 78 degrees C), saline (Menotreat, 85 degrees ) and glycerine (Thermablate, 173 degrees C). All balloons require pressurization from 160 to 240 mmHg for treatment cycles of 2 to 10 minutes. Prior to TBEA, preoperative endometrial thinning, including suction curettage, is optional. Several RCTs and cohort studies indicate that the advantages of TBEA include portability, ease of use and short learning curve. In addition, small diameter catheters requiring minimal cervical dilatation (5-7 mm) and short duration of treatment cycles (2-8 min) allow treatment under minimal analgesia/anesthesia requirements in a clinic setting. Following TBEA serious adverse events, including thermal injuries to viscera have been experienced. To minimize such injuries some surgeons advocate the use of routine post-dilatation hysteroscopy and/or ultrasonography to confirm correct intrauterine placement of the balloon prior to initiating the treatment cycle. After 10 years of clinical practice, TBEA is thought to be the preferred first-line surgical treatment of menorrhagia in appropriately selected candidates. Economic modeling also suggested that TBEA may be more cost-effective than HEA.

  18. Balloon-Borne Infrasound Detection of Energetic Bolide Events (United States)

    Young, Eliot F.; Ballard, Courtney; Klein, Viliam; Bowman, Daniel; Boslough, Mark


    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.

  19. Properties of nylon 12 balloons after thermal and liquid carbon dioxide treatments. (United States)

    Ro, Andrew J; Davé, Vipul


    Critical design attributes of angioplasty balloons include the following: tear resistance, high burst pressures, controlled compliance, and high fatigue. Balloons must have tear resistance and high burst pressures because a calcified stenosis can be hard and nominal pressures of up to 16 atm can be used to expand the balloon. The inflated balloon diameter must be a function of the inflation pressure, thus compliance is predictable and controlled. Reliable compliance is necessary to prevent damage to vessel walls, which may be caused by over-inflation. Balloons are often inflated multiple times in a clinical setting and they must be highly resistant to fatigue. These design attributes are dependent on the mechanical properties and polymer morphology of the balloon. The effects of residual stresses on shrinkage, crystallite orientation, balloon compliance, and mechanical properties were studied for angioplasty nylon 12 balloons. Residual stresses of these balloons were relieved by oven heat treatment and liquid CO2 exposure. Residual stresses were measured by quantifying shrinkage at 80 °C of excised balloon samples using a dynamic mechanical analyzer. Shrinkage was lower after oven heat treatment and liquid CO2 exposure compared to the as-received balloons, in the axial and radial directions. As-received, oven heat treated, and liquid CO2-exposed balloon samples exhibited similar thermal properties (T(g), T(m), X(t)). Crystallite orientation was not observed in the balloon cylindrical body using X-ray scattering and polarized light microscopy, which may be due to balloon fabrication conditions. Significant differences were not observed between the stress-strain curves, balloon compliance, and average burst pressures of the as-received, oven heat treated, and liquid CO2-exposed balloons.

  20. Emerging Stent and Balloon Technologies in the Femoropopliteal Arteries

    Directory of Open Access Journals (Sweden)

    Georgios Pastromas


    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.

  1. AIAA Educator Academy: The Space Weather Balloon Module (United States)

    Longmier, B.; Henriquez, E.; Bering, E. A.; Slagle, E.


    Educator Academy is a K-12 STEM curriculum developed by the STEM K-12 Outreach Committee of the American Institute of Aeronautics and Astronautics (AIAA). Consisting of three independent curriculum modules, K-12 students participate in inquiry-based science and engineering challenges to improve critical thinking skills and enhance problem solving skills. The Space Weather Balloon Curriculum Module is designed for students in grades 9-12. Throughout this module, students learn and refine physics concepts as well as experimental research skills. Students participate in project-based learning that is experimental in nature. Students are engaged with the world around them as they collaborate to launch a high altitude balloon equipped with HD cameras.The program leaders launch high altitude weather balloons in collaboration with schools and students to teach physics concepts, experimental research skills, and to make space exploration accessible to students. A weather balloon lifts a specially designed payload package that is composed of HD cameras, GPS tracking devices, and other science equipment. The payload is constructed and attached to the balloon by the students with low-cost materials. The balloon and payload are launched with FAA clearance from a site chosen based on wind patterns and predicted landing locations. The balloon ascends over 2 hours to a maximum altitude of 100,000 feet where it bursts and allows the payload to slowly descend using a built-in parachute. The payload is located using the GPS device. In April 2012, the Space Weather Balloon team conducted a prototype field campaign near Fairbanks Alaska, sending several student-built experiments to an altitude of 30km, underneath several strong auroral displays. To better assist teachers in implementing one or more of these Curriculum Modules, teacher workshops are held to give teachers a hands-on look at how this curriculum is used in the classroom. And, to provide further support, teachers are each

  2. Balloon-Borne System Would Aim Instrument Toward Sun (United States)

    Polites, M. E.


    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. Intrauterine tamponade balloon use in the treatment of uterine inversion. (United States)

    Haeri, Sina; Rais, Sheliza; Monks, Brian


    Uterine inversion is a rare but life-threatening obstetrical emergency that occurs when the fundus of the uterus prolapses through the cervix, hence turning the uterus inside out. In this case report, we present our experience using an intrauterine tamponade balloon for management of uterine inversion, and a review of the literature. The utility of an intrauterine tamponade balloon in cases of uterine inversion, especially when maternal medical conditions preclude the use of uterotonics, or reinversion is observed should be kept in mind.

  4. Cosmic ray abundance measurements with the CAKE balloon experiment

    CERN Document Server

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


    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

  5. Simultaneous electric-field measurements on nearby balloons. (United States)

    Mozer, F. S.


    Electric-field payloads were flown simultaneously on two balloons from Great Whale River, Canada, on September 21, 1971, to provide data at two points in the upper atmosphere that differed in altitude by more than one atmospheric density scale height and in horizontal position by 30-140 km. The altitude dependences in the two sets of data prove conclusively that the vertical electric field at balloon altitudes stems from fair-weather atmospheric electricity sources and that the horizontal fields are mapped down ionospheric fields, since the weather-associated horizontal fields were smaller than 2 mV/m.

  6. Modulational instability of nematic phase

    Indian Academy of Sciences (India)

    T Mithun; K Porsezian


    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. Weibel instability with nonextensive distribution

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Hui-Bin; Liu, Shi-Bing [Strong-field and Ultrafast Photonics Lab, Institute of Laser Engineering, Beijing University of Technology, Beijing 100124 (China)


    Weibel instability in plasma, where the ion distribution is isotropic and the electron component of the plasma possesses the anisotropic temperature distribution, is investigated based on the kinetic theory in context of nonextensive statistics mechanics. The instability growth rate is shown to be dependent on the nonextensive parameters of both electron and ion, and in the extensive limit, the result in Maxwellian distribution plasma is recovered. The instability growth rate is found to be enhanced as the nonextensive parameter of electron increases.

  8. Political Instability and Economic Growth


    Swagel, Phillip; Roubini, Nouriel; Ozler, Sule; Alesina, Alberto


    This paper investigates the relationship between political instability and per capita GDP growth in a sample of 113 countries for the period 1950-1982. We define ?political instability? as the propensity of a government collapse, and we estimate a model in which political instability and economic growth are jointly determined. The main result of this paper is that in countries and time periods with a high propensity of government collapse, growth is significantly lower than otherwise. This ef...

  9. BioEnterics Intragastric Balloon (BIB) versus Spatz Adjustable Balloon System (ABS): Our experience in the elderly. (United States)

    Russo, Teresa; Aprea, Giovanni; Formisano, Cesare; Ruggiero, Simona; Quarto, Gennaro; Serra, Raffaele; Massa, Guido; Sivero, Luigi


    The BioEnterics Intragastric Balloon (BIB) and the Spatz Adjustable Balloon System (ABS) are in fact recommended for weight reduction as a bridge to bariatric surgery. We retrospected studied patients with body mass index (BMI) and age ranges of 37-46 and 70-80 years, respectively, who had undergone BIB from January 2010 to July 2012 and prospected studied patients who had undergone Spatz balloon from July 2012 to August 2014. The aim of this study is to compare BIB and Spatz in terms of weight loss, complications, and maintenance of weight after removal. For both procedures, the median weight loss was 20 ± 3 kg, median BMI at the end of the therapy was 32 ± 2, and no severe complication occurred.

  10. Large bowel impaction by the BioEnterics Intragastric Balloon (BIB) necessitating surgical intervention. (United States)

    Kim, W Y; Kirkpatrick, U J; Moody, A P; Wake, P N


    A case of large bowel impaction caused by migration of a BioEnterics Intragastric Balloon (BIB) is presented. The literature is reviewed regarding both the use and the complications inherent in such balloon devices. This is the first reported case of an intragastric balloon impacted in the colon 9 months after insertion.

  11. Libration driven multipolar instabilities

    CERN Document Server

    Cébron, David; Herreman, Wietze


    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...

  12. Instability of enclosed horizons

    CERN Document Server

    Kay, Bernard S


    We study the classical massless scalar wave equation on the region of 1+1-dimensional Minkowski space between the two branches of the hyperbola $x^2-t^2=1$ with vanishing boundary conditions on it. We point out that there are initially finite-energy initially, say, right-going waves for which the stress-energy tensor becomes singular on the null-line $t+x=0$. We also construct the quantum theory of this system and show that, while there is a regular Hartle-Hawking-Israel-like state, there are coherent states built on this for which there is a similar singularity in the expectation value of the renormalized stress-energy tensor. We conjecture that in 1+3-dimensional situations with 'enclosed horizons' such as a (maximally extended) Schwarzschild black hole in equilibrium in a stationary box or the (maximally extended) Schwarzschild-AdS spacetime, there will be a similar singularity at the horizon and that would signal an instability when matter perturbations and/or gravity are switched on. Such an instability ...

  13. [Aspirin suppresses microsatellite instability]. (United States)

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


    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.

  14. Hybrid Global Communication Architecture with Balloons and Satellites (United States)

    Pignolet, G.; Celeste, A.; Erb, B.


    Global space communication systems have been developed now for more than three decades, based mainly on geostationary satellites or almost equivalent systems such as the Molnya orbit concepts. The last decade of the twentieth century has seen the emergence of satellite constellations in low or medium Earth orbit, in order to improve accessibility in terms of visibility at higher latitudes and limited size or power requirement for ground equipment. However such systems are complex to operate, there are still many situations where connection may remain difficult to achieve, and commercial benefits are still to be proven. A new concept, using a network combination of geostationary relay satellites and high altitude stratospheric platforms may well overcome the inconveniences of both geostationary systems and satellite constellations to improve greatly global communication in the future. The emergence of enabling technologies developed in Japan and in several other countries will soon make it possible to fly helium balloons in the upper layers of the atmosphere, at altitudes of 20 km or more. At such an altitude, well above the meteorological disturbances and the jet-streams, the stratosphere enjoys a regular wind at moderate speeds ranging between 10 m/s and 30 m/s, depending on latitude and also on season. It is possible for balloons powered by electric engines to fly non- stop upstream of the wind in order to remain stationary above a particular location. Large balloons, with sizes up to 300 m in length, would be able to carry sub-satellite communication payloads, as well as observation apparatus and scientific equipment. The range of visibility for easy both-way communication between the balloon and operators or customers on the ground could be as large as 200 km in radius. Most current studies consider a combination of solar cells and storage batteries to power the balloons, but microwave beam wireless power transportation from the ground could be a very

  15. Scientific Ballooning Technologies Workshop STO-2 Thermal Design and Analysis (United States)

    Ferguson, Doug


    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.

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

    NARCIS (Netherlands)

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


    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

  17. Balloon dacryocystoplasty study in the management of adult epiphora.

    LENUS (Irish Health Repository)

    Fenton, S


    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.

  18. 28. Critical pulmonary valve stenosis: Medical management beyond balloon dilation

    Directory of Open Access Journals (Sweden)

    Muhammad Arif Khan


    Conclusion: Phentolamine and/or Captopril have a therapeutic role in neonates with critical PVS who remain oxygen dependent after balloon dilation. Both medicationslead to vasodilatation of pulmonary and systemic vascularity. They facilitate inflowto the right ventricle. Right to left shunt across a PFO or/ ASD minimizesand saturation improves leading to a significantreduction in length of hospitalization.

  19. Latex micro-balloon pumping in centrifugal microfluidic platforms. (United States)

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


    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.

  20. Balloon atrial septostomy under echocardiographic guide: case series

    Directory of Open Access Journals (Sweden)

    SM Meraji


    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.

  1. Using Hydrogen Balloons to Display Metal Ion Spectra (United States)

    Maynard, James H.


    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. Meshed-Pumpkin Super-Pressure Balloon Design (United States)

    Jones, Jack; Yavrouian, Andre


    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.

  3. 75 FR 77673 - National Environmental Policy Act: Scientific Balloon Program (United States)


    ... SPACE ADMINISTRATION National Environmental Policy Act: Scientific Balloon Program AGENCY: National... the National Environmental Policy Act (NEPA) of 1969, as amended (42 U.S.C. 4321, et seq.); the Council on Environmental Quality Regulations for Implementing the Procedural Provisions of NEPA (40...

  4. Complications of flow-directed balloon-tipped catheters. (United States)

    Smart, F W; Husserl, F E


    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.

  5. An automatic parachute release for high altitude scientific balloons (United States)

    Field, Chris

    NASA's Columbia Scientific Balloon Facility launches high altitude scientific research balloons at many locations around the world. Locations like Antarctica are flat for hundreds of miles and have nothing to snag a parachute consequently causing it to be more important to separate the parachute from the payload than in an area with vegetation and fences. Scientists are now building one of a kind payloads costing millions of dollars, taking five years or more to build, and are requesting multiple flights. In addition to that, the data gathering rate of many science payloads far exceeds the data downlink rate on over-the-horizon flights therefore making a recovery of at least the data hard drives a "minimum success requirement". The older mentality in ballooning; separating the parachute and payload from the balloon and getting it on the ground is more important than separating the parachute after the payload is on the ground has changed. It is now equally as important to separate the parachute from the gondola to prevent damage from dragging. Until now, commands had to be sent to separate the parachute from the gondola at approximately 60K ft, 30K ft, and 10K ft to use the Semi Automatic Parachute Release (SAPR), which is after the sometimes violent parachute opening shock. By using the Gondola controlled Automatic Parachute Release (GAPR) all commanding is done prior to termination, making the parachute release fully autonomous.

  6. The Micro-Instrumentation Package: A Solution to Lightweight Ballooning (United States)

    Juneau, Jill

    This paper discusses the design and testing of an over the horizon (OTH) light weight telemetry and termination system that can be used for small ballooning payloads. Currently, the Columbia Scientific Balloon Facility (CSBF) provides telemetry for the science payload by integrating one of two types of support packages. The type of support package integrated depends on whether the flight will stay in range of line of sight (LOS) or will exceed LOS requiring the use of over the horizon (OTH) telemetry. The weights of these systems range from 100 pounds to 350 pounds depending upon the use of redundant systems, equipment for high data rates, and batteries and/or solar panels for power requirements. These weight values are not as significant for larger payloads but can be crippling for smaller payloads. In addition, these support package systems are fairly expensive, placing a high importance on recovery. A lightweight and inexpensive telemetry system could be beneficial for various reasons. First, it would allow scientists to fly lightweight payloads on large balloons reaching even higher altitudes. Second, scientists could fly lightweight payloads on less expensive balloons such as meteorological balloons. Depending on the payload, these flights could be fairly inexpensive and even disposable. Third, a compact telemetry system on any balloon will free up more room for the science portion of the payload. In response, a compact telemetry/termination system called the Micro-Instrumentation Package (MIP) was developed. The MIP provides uplink and downlink communications, an interface to the science, housekeeping information including global positioning system (GPS) position, and relays. Instead of a power-hungry microprocessor, the MIP's central consists of a microcontroller. Microcontrollers are lower power, easily programmed, and can be purchased for less than ten dollars. For uplink and downlink telemetry, the MIP uses an LOS serial transceiver and an Iridium unit

  7. Angioplasty with drug coated balloons for the treatment of infrainguinal peripheral artery disease. (United States)

    Werner, Martin


    Restenosis or re-occlusion after femoropopliteal angioplasty or stent implantation is the main limitation of endovascular treatment strategies for peripheral artery disease. Within the last years, balloon catheters with anti-proliferative drug coating on the balloon surface have shown to be associated with higher patency rates compared to plain balloon angioplasty. Thus, drug-coated balloons were gradually adopted in many interventional centres for the treatment of femoropopliteal obstructions. The current review summarises the existing evidence for drug-coated balloons in the infrainguinal vessels and their indication in special lesion cohorts.

  8. Bony instability of the shoulder. (United States)

    Bushnell, Brandon D; Creighton, R Alexander; Herring, Marion M


    Instability of the shoulder is a common problem treated by many orthopaedists. Instability can result from baseline intrinsic ligamentous laxity or a traumatic event-often a dislocation that injures the stabilizing structures of the glenohumeral joint. Many cases involve soft-tissue injury only and can be treated successfully with repair of the labrum and ligamentous tissues. Both open and arthroscopic approaches have been well described, with recent studies of arthroscopic soft-tissue techniques reporting results equal to those of the more traditional open techniques. Over the last decade, attention has focused on the concept of instability of the shoulder mediated by bony pathology such as a large bony Bankart lesion or an engaging Hill-Sachs lesion. Recent literature has identified unrecognized large bony lesions as a primary cause of failure of arthroscopic reconstruction for instability, a major cause of recurrent instability, and a difficult diagnosis to make. Thus, although such bony lesions may be relatively rare compared with soft-tissue pathology, they constitute a critically important entity in the management of shoulder instability. Smaller bony lesions may be amenable to arthroscopic treatment, but larger lesions often require open surgery to prevent recurrent instability. This article reviews recent developments in the diagnosis and treatment of bony instability.

  9. Cinerama sickness and postural instability

    NARCIS (Netherlands)

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


    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

  10. Marital instability after midlife. (United States)

    Wu, Z; Penning, M J


    "Divorce in later life has been shown to produce dramatic declines in the economic, psychological, and physical well-being of marital partners. This study examines the prevalence and determinants of marital disruption after midlife using Becker's theory of marital instability. Using recent Canadian national data, the marital outcomes of women and men who were married as of age 40 are tracked across the remaining years of the marriage. Cox proportional hazard regression models indicate stabilizing effects of the duration of the marriage, the age at first marriage, the presence of young children, as well as of remarriage for middle-aged and older persons. Other significant risk factors include education, heterogamous marital status, premarital cohabitation, number of siblings, and region."

  11. 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...... use of interface elements) is used successfully to model cases where the path of the discontinuity is known in advance, as is the case of the analysis of pull-out of fibers embedded in a concrete matrix. This method is applied to the case of non-straight fibers and fibers with forces that have....... 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...

  12. The bar instability revisited

    CERN Document Server

    Chiodi, Filippo; Claudin, Philippe


    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...

  13. Instability and Information

    CERN Document Server

    Patzelt, Felix


    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.

  14. High Altitude Infrasound Measurements using Balloon-Borne Arrays (United States)

    Bowman, D. C.; Johnson, C. S.; Gupta, R. A.; Anderson, J.; Lees, J. M.; Drob, D. P.; Phillips, D.


    For the last fifty years, almost all infrasound sensors have been located on the Earth's surface. A few experiments consisting of microphones on poles and tethered aerostats comprise the remainder. Such surface and near-surface arrays likely do not capture the full diversity of acoustic signals in the atmosphere. Here, we describe results from a balloon mounted infrasound array that reached altitudes of up to 38 km (the middle stratosphere). The balloon drifted at the ambient wind speed, resulting in a near total reduction in wind noise. Signals consistent with tropospheric turbulence were detected. A spectral peak in the ocean microbarom range (0.12 - 0.35 Hz) was present on balloon-mounted sensors but not on static infrasound stations near the flight path. A strong 18 Hz signal, possibly related to building ventilation systems, was observed in the stratosphere. A wide variety of other narrow band acoustic signals of uncertain provenance were present throughout the flight, but were absent in simultaneous recordings from nearby ground stations. Similar phenomena were present in spectrograms from the last balloon infrasound campaign in the 1960s. Our results suggest that the infrasonic wave field in the stratosphere is very different from that which is readily detectable on surface stations. This has implications for modeling acoustic energy transfer between the lower and upper atmosphere as well as the detection of novel acoustic signals that never reach the ground. Our work provides valuable constraints on a proposed mission to detect earthquakes on Venus using balloon-borne infrasound sensors.

  15. Odontoid balloon kyphoplasty associated with screw fixation for Type II fracture in 2 elderly patients. (United States)

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


    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.

  16. Gravitational Instabilities in Circumstellar Disks

    CERN Document Server

    Kratter, Kaitlin M


    [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...

  17. Beam instability Workshop - plenary sessions

    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

  18. Equilibrium Electro-osmotic Instability

    CERN Document Server

    Rubinstein, Isaak


    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...

  19. Instability in Shocked Granular Gases

    CERN Document Server

    Sirmas, Nick; Radulescu, Matei


    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.

  20. Instability in shocked granular gases (United States)

    Sirmas, Nick; Falle, Sam; Radulescu, Matei


    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.

  1. Gravitational Instabilities in Circumstellar Disks (United States)

    Kratter, Kaitlin; Lodato, Giuseppe


    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

  2. Cutting balloon angioplasty vs. conventional balloon angioplasty in patients receiving intracoronary brachytherapy for the treatment of in-stent restenosis. (United States)

    Fasseas, Panayotis; Orford, James L; Lennon, Ryan; O'Neill, Jessica; Denktas, Ali E; Panetta, Carmelo J; Berger, Peter B; Holmes, David R


    The objective of this study was to evaluate the safety and efficacy of cutting balloon angioplasty (CBA) for the treatment of in-stent restenosis prior to intracoronary brachytherapy (ICB). Cutting balloon angioplasty may reduce the incidence of uncontrolled dissection requiring adjunctive stenting and may limit "melon seeding" and geographic miss in patients with in-stent restenosis who are subsequently treated with ICB. We performed a retrospective case-control analysis of 134 consecutive patients with in-stent restenosis who were treated with ICB preceded by either CBA or conventional balloon angioplasty. We identified 44 patients who underwent CBA and ICB, and 90 control patients who underwent conventional percutaneous transluminal coronary angioplasty (PTCA) and ICB for the treatment of in-stent restenosis. Adjunctive coronary stenting was performed in 13 patients (29.5%) in the CBA/ICB group and 41 patients (45.6%; P 0.05). Despite sound theoretical reasons why CBA may be better than conventional balloon angioplasty for treatment of in-stent restenosis with ICB, and despite a reduction in the need for adjunctive coronary stenting, we were unable to identify differences in clinical outcome.

  3. 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)


    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

  4. 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)


    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

  5. Impact of intra-aortic balloon counterpulsation with different balloon volumes on cardiac performance in humans. (United States)

    Cohen, Marc; Fasseas, Panayotis; Singh, Varinder P; McBride, Ruth; Orford, James L; Kussmaul, William G


    Intra-aortic balloon (IAB) counterpulsation can augment the cardiac output. However, the effect of different IAB volumes on cardiac performance has not been adequately evaluated in humans. Eighty-two patients (52 males [63%]; mean age, 65 +/- 12 years; mean body surface area [BSA], 1.8 +/- 0.2 m(2)) had IAB counterpulsation for cardiogenic shock, refractory angina, and preoperatively for high-risk cardiac surgery. Cardiac hemodynamics were prospectively studied during IAB with inflation volumes of 32 vs. 40 cc. Hemodynamic data collected included aortic pressure, pulmonary artery pressure, systemic and mixed venous oxygen saturations, and cardiac output (by Fick). Transthoracic echocardiography (TTE) was used to obtain both velocity time integrals (VTIs) and the area of the left ventricular outflow tract (LVOT). Left ventricular stroke volume was then calculated as LVOT area x VTI. Cardiac output (CO) determined by the Fick method and VTI did not differ significantly (P = NS) between the two inflation volumes (y = 0.002 + 0.97x). In a subgroup of 33 patients with BSA

  6. 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: [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)


    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.

  7. Using High Resolution Balloon Photography to Provide Topographic Data (United States)

    Russell, K.; Bauer, T.


    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

  8. Abelianization of QCD plasma instabilities (United States)

    Arnold, Peter; Lenaghan, Jonathan


    QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what nonlinear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities in the nonlinear regime may have close parallels to similar processes in traditional plasma physics. We conjecture that the physics of collisionless plasma instabilities in SU(2) and SU(3) gauge theory becomes equivalent, respectively, to (i) traditional plasma physics, which is U(1) gauge theory, and (ii) plasma physics of U(1)×U(1) gauge theory.

  9. The Advanced Scintillator Compton Telescope (ASCOT) balloon project (United States)

    Bloser, Peter F.; Sharma, Tejaswita; Legere, Jason S.; Bancroft, Christopher M.; McConnell, Mark L.; Ryan, James M.; Wright, Alex M.


    We describe a project to develop new medium-energy gamma-ray instrumentation by constructing and flying a balloon-borne Compton telescope using advanced scintillator materials combined with silicon photomultiplier readouts. There is a need in high-energy astronomy for a medium-energy gamma-ray mission covering the energy range from approximately 0.4 - 20 MeV to follow the success of the COMPTEL instrument on CGRO. We believe that directly building on the legacy of COMPTEL, using relatively robust, low-cost, off-the-shelf technologies, is the most promising path for such a mission. Fortunately, high-performance scintillators, such as Lanthanum Bromide (LaBr3), Cerium Bromide (CeBr3), and p-terphenyl, and compact readout devices, such as silicon photomultipliers (SiPMs), are already commercially available and capable of meeting this need. We have conducted two balloon flights of prototype instruments to test these technologies. The first, in 2011, demonstrated that a Compton telescope consisting of an liquid organic scintillator scattering layer and a LaBr3 calorimeter effectively rejects background under balloon-flight conditions, using time-of-flight (ToF) discrimination. The second, in 2014, showed that a telescope using an organic stilbene crystal scattering element and a LaBr3 calorimeter with SiPM readouts can achieve similar ToF performance. We are now constructing a much larger balloon instrument, an Advanced Scintillator Compton Telescope (ASCOT) with SiPM readout, with the goal of imaging the Crab Nebula at MeV energies in a one-day flight. We expect a 4σ detection up to 1 MeV in a single transit. We present calibration results of the first detector modules, and updated simulations of the balloon instrument sensitivity. If successful, this project will demonstrate that the energy, timing, and position resolution of this technology are sufficient to achieve an order of magnitude improvement in sensitivity in the mediumenergy gamma-ray band, were it to be

  10. A Spreadsheet Simulation Tool for Terrestrial and Planetary Balloon Design (United States)

    Raquea, Steven M.


    During the early stages of new balloon design and development, it is necessary to conduct many trade studies. These trade studies are required to determine the design space, and aid significantly in determining overall feasibility. Numerous point designs then need to be generated as details of payloads, materials, mission, and manufacturing are determined. To accomplish these numerous designs, transient models are both unnecessary and time intensive. A steady state model that uses appropriate design inputs to generate system-level descriptive parameters can be very flexible and fast. Just such a steady state model has been developed and has been used during both the MABS 2001 Mars balloon study and the Ultra Long Duration Balloon Project. Using Microsoft Excel's built-in iteration routine, a model was built. Separate sheets were used for performance, structural design, materials, and thermal analysis as well as input and output sheets. As can be seen from figure 1, the model takes basic performance requirements, weight estimates, design parameters, and environmental conditions and generates a system level balloon design. Figure 2 shows a sample output of the model. By changing the inputs and a few of the equations in the model, balloons on earth or other planets can be modeled. There are currently several variations of the model for terrestrial and Mars balloons, as well there are versions of the model that perform crude material design based on strength and weight requirements. To perform trade studies, the Visual Basic language built into Excel was used to create an automated matrix of designs. This trade study module allows a three dimensional trade surface to be generated by using a series of values for any two design variables. Once the fixed and variable inputs are defined, the model automatically steps through the input matrix and fills a spreadsheet with the resulting point designs. The proposed paper will describe the model in detail, including current

  11. Instability of ties in compression

    DEFF Research Database (Denmark)

    Buch-Hansen, Thomas Cornelius


    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...... exact instability solutions are complex to derive, not to mention the extra complexity introducing dimensional instability from the temperature gradients. Using an inverse variable substitution and comparing an exact theory with an analytical instability solution a method to design tie...

  12. Microsatellite instability in bladder cancer

    DEFF Research Database (Denmark)

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


    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...... chromosome for three tumors. Single locus alterations were detected in three tumors, while three other tumors revealed changes in two or more loci. In one tumor we found microsatellite instability in all five loci analyzed on chromosome 9. The alterations detected were either minor 2-base pair changes...

  13. An analysis of the deployment of a pumpkin balloon at Mars (United States)

    Rand, J. L.; Phillips, M. L.


    The design of large superpressure balloons has received significant attention in recent years due to the successful demonstration of various enabling technologies and materials. Of particular note is the "pumpkin" shaped balloon concept, which allows the stress in the envelope to be limited by the surface geometry. Unlike a sphere, where the radius used to determine the stress is determined by the volume of the balloon, the pumpkin utilizes a system of meridional tendons to react the loading in one direction, and form a number of lobes, which limit the stress in the circumferential direction. A suitable superpressure balloon has been designed using this technology which will carry 2 kg in the atmosphere of Mars. The deployment of this balloon is assumed to occur while falling on a decelerator suitably designed for the Mars atmosphere. The inflation is accomplished by a 10 kg system suspended at the nadir of the balloon. As the system falls toward the surface of the planet, helium gas is transferred into the balloon, forming a partially inflated system very similar to an ascending zero pressure balloon. This analysis incorporates the flow of the planetary gas around the inflating balloon which alters the pressure distribution and shape. As a result, stresses are seen to increase beyond the design values which will require the balloon to be redesigned to accommodate this type of dynamic deployment.

  14. Apical ballooning-like syndrome: Hypocalcemia? What else!

    Directory of Open Access Journals (Sweden)

    Maria Accadia


    Full Text Available Apical ballooning syndrome (ABS, also known as Takotsubo or stress cardiomyopathy, is characterised by acute, transient and severe LV dysfunction, mimicking myocardial infarction; it occurs, in most cases, in the absence of obstructive coronary disease and is precipitated by severe emotional or physical stress, but many other potential triggers has been identi ed in the last years. Although the pathogenesis of ABS remains unclear, the most common mechanisms suggested are coronary vasospam and an exaggerated sympathetic activation associated to high levels of plasma cathecolamine leading to cardiotoxicity.We describe two cases of Apical Ballooning like Syndrome that were triggered by severe, acute hypocalcemia, without evidence of coronary vasospasm and with normal hematic level of cathecolamines.

  15. Developing International Standards for Meteorological Balloon to Facilitate Industrial Progress

    Institute of Scientific and Technical Information of China (English)

    Deng Yizhi


    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.

  16. MIPAS Ozone Validation by Stratospheric Balloon and Aircraft Measurements (United States)

    Cortesi, U.; Blom, C. E.; Camy-Peyret, C.; Chance, K.; Davies, J.; Goutail, F.; Kuttippurath, J.; McElroy, C. T.; Mencaraglia, F.; Oelhaf, H.; Petritoli, A.; Pirre, M.; Pommereau, J. P.; Ravegnani, F.; Renard, J. B.; Strong, K.


    A number of in situ and remote sensing techniques for the measurement of upper tropospheric and stratospheric O3 content was employed during dedicated experiments of the ESABC programme, aiming at the validation of the ENVISAT chemistry payload. In this paper, we will be focusing on the validation of MIPAS off-line products, by presenting the results of the intercomparison between MIPAS O3 vertical profiles and aircraft and balloon correlative measurements. First priority is given to the validation of processor v4.61 data, but individual results of 2002 and 2003 balloon observations are also compared with MIPAS O3 non operational data. Some general remarks are finally expressed, along with specific recommendation to fully exploit the available ESABC validation dataset

  17. Evaporative instabilities in climbing films (United States)

    Hosoi, A. E.; Bush, John W. M.


    We consider flow in a thin film generated by partially submerging an inclined rigid plate in a reservoir of ethanol or methanol water solution and wetting its surface. Evaporation leads to concentration and surface tension gradients that drive flow up the plate. An experimental study indicates that the climbing film is subject to two distinct instabilities. The first is a convective instability characterized by flattened convection rolls aligned in the direction of flow and accompanied by free-surface deformations; in the meniscus region, this instability gives rise to pronounced ridge structures aligned with the mean flow. The second instability, evident when the plate is nearly vertical, takes the form of transverse surface waves propagating up the plate.

  18. 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


    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...

  19. Atlantoaxial instability in Down's syndrome


    J Gordon Millichap


    The radiographs and clinical evaluations of 90 children with Down’s syndrome were reassessed after an interval of 5 years in a study of atlantoaxial instability (AAI) at the Derbyshire Children’s Hospital and Infirmary, Derby, UK.

  20. Apical ballooning-like syndrome: Hypocalcemia? What else!


    Maria Accadia; Marianna Abitabile; Salvatore Rumolo; Scotto di Uccio Fortunato; Luigi Irace; Andrea Tuccillo; Giuseppe Mercogliano; Bernardino Tuccillo


    Apical ballooning syndrome (ABS), also known as Takotsubo or stress cardiomyopathy, is characterised by acute, transient and severe LV dysfunction, mimicking myocardial infarction; it occurs, in most cases, in the absence of obstructive coronary disease and is precipitated by severe emotional or physical stress, but many other potential triggers has been identi ed in the last years. Although the pathogenesis of ABS remains unclear, the most common mechanisms suggested are coronary vasospam an...

  1. The Extreme Universe Space Observatory Super Pressure Balloon Mission (United States)

    Wiencke, Lawrence; Olinto, Angela; Adams, Jim; JEM-EUSO Collaboration


    The Extreme Universe Space Observatory on a super pressure balloon (EUSO-SPB) mission will make the first fluorescence observations of high energy cosmic ray extensive air showers by looking down on the atmosphere from near space. A long duration flight of at least 50 nights launched from Wanaka NZ is planned for 2017. We describe completed instrument, and the planned mission. We acknowledge the support of NASA through grants NNX13AH53G and NNX13AH55G.

  2. Astronomical observations with the University College London balloon borne telescope (United States)

    Jennings, R. E.


    The characteristics of a telescope system which was developed for high altitude balloon astronomy are discussed. A drawing of the optical system of the telescope is provided. A sample of the signals recorded during one of the flights is included. The correlation between the infrared flux and the radio continuum flux is analyzed. A far infrared map of the radio and infrared peaks of selected stars is developed. The spectrum of the planet Saturn is plotted to show intensity as compared with wavenumber.

  3. 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


    @@ 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.

  4. Balloon Kyphoplasty: An Effective Treatment for Kummell Disease? (United States)

    Kim, Pius


    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

  5. Prime time for drug eluting balloons in SFA interventions? (United States)

    Brodmann, M


    Peripheral arterial disease most commonly affects the femoropopliteal segment. Despite enormous improvements in device and treatment technology the long-term patency rate and clinical benefit of endovascular treatment in the respective vascular bed is not satisfying. Drug coated balloon technology as a treatment option in femoropopliteal disease has shown encouraging results in first-in-man trials, which have now been proven in large randomized controlled trials.

  6. NEW APPROACHES: A hot air balloon from dustbin liners (United States)

    Weaver, Nicholas


    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.

  7. 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)


    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.)

  8. Material Instabilities in Particulate Systems (United States)

    Goddard, J. D.


    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.

  9. A Sensitivity Analysis of fMRI Balloon Model

    KAUST Repository

    Zayane, Chadia


    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.

  10. The Rocket Balloon (Rocketball): Applications to Science, Technology, and Education (United States)

    Esper, Jaime


    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.

  11. Balloon Cell Urethral Melanoma: Differential Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    M. McComiskey


    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.

  12. 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


    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...

  13. Precision Attitude Control for the BETTII Balloon-Borne Interferometer (United States)

    Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen


    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.

  14. Low Cost Balloon programme of Indian Centre for Space Physics (United States)

    Chakrabarti, Sandip Kumar


    Indian Centre for Space Physics has launched 89 Missions to near space using single or multiple weather balloons or very light plastic balloons. Basic goal was to capitalize miniaturization of equipments in modern ages. Our typical payload of less than 4kg weight consists of GPS, video camera, cosmic ray detectors, Attitude measurement unit, sunsensor and most importantly a 50-100sqcm X-ray/Gamma-ray detector (usually a scintillator type). The main purpose of the latter is to study spectra of secondary cosmic ray spectra (till our ceiling altitude of 36-42km) over the years and their seasonal variation or variation with solar cycle. We also study solar X-ray spectra, especially of solar flares. We have detected a Gamma Ray Burst (GRB) and pulsars. Our observation of black hole candidates did not yield satisfactory result yet mainly because of poor collimation (~ 10 deg x 10 deg) by lead collimator which introduces strong background also. Our effort with multiple balloon flights enabled us to have long duration flights. We believe that our procedure is very futuristic and yet at an affordable cost.

  15. A Low Cost Weather Balloon Borne Solar Cell Calibration Payload (United States)

    Snyder, David B.; Wolford, David S.


    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. .

  16. Instability of enclosed horizons (United States)

    Kay, Bernard S.


    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.

  17. Vector-Resonance-Multimode Instability (United States)

    Sergeyev, S. V.; Kbashi, H.; Tarasov, N.; Loiko, Yu.; Kolpakov, S. A.


    The modulation and multimode instabilities are the main mechanisms which drive spontaneous spatial and temporal pattern formation in a vast number of nonlinear systems ranging from biology to laser physics. Using an Er-doped fiber laser as a test bed, here for the first time we demonstrate both experimentally and theoretically a new type of a low-threshold vector-resonance-multimode instability which inherits features of multimode and modulation instabilities. The same as for the multimode instability, a large number of longitudinal modes can be excited without mode synchronization. To enable modulation instability, we modulate the state of polarization of the lasing signal with the period of the beat length by an adjustment of the in-cavity birefringence and the state of polarization of the pump wave. As a result, we show the regime's tunability from complex oscillatory to periodic with longitudinal mode synchronization in the case of resonance matching between the beat and cavity lengths. Apart from the interest in laser physics for unlocking the tunability and stability of dynamic regimes, the proposed mechanism of the vector-resonance-multimode instability can be of fundamental interest for the nonlinear dynamics of various distributed systems.

  18. The Liege-balloon program. [balloon-borne instruments for high-spectral resolution observations of the sun (United States)

    Zander, R.


    The Liege-balloon program is intended to make high-spectral resolution observations of the sun in the near- and intermediate infrared regions not accessible from the ground. A description of the equipment, followed by a summary of the data obtained till now is presented. Except for ozone whose maximum of concentration lies near 25 Km altitude, the residual mass distribution of the other mentioned molecules decreases with altitude. This is a self-explanatory argument for carrying out spectroscopic observations from platforms transcending the densest layers of the earth's atmosphere. The Liege balloon equipment is primarily intended for very high-resolution solar observations from about 27-30 Km altitude, in all spectral regions between 1.5 and 15.0 microns, not accessible from the ground.

  19. Double Balloon Cervical Ripening Catheter for Control of Massive Hemorrhage in a Cervical Ectopic Pregnancy (United States)

    Zambrano, Nabila; Reilly, James; Moretti, Michael


    Cervical pregnancy can be complicated by perfuse vaginal bleeding. Mechanical compression directed at tamponing the cervical vessels can control hemostasis. There are several types of balloon catheters that have been described for cervical compression. However use of a double balloon catheter is a novel approach for cervical tamponade, as one balloon is positioned below the external cervical os and the second balloon is situated above in the internal cervical os. This compresses the cervix from internal os to external os between the two balloons, forming a “cervical sandwich.” We describe this method of cervical tamponade using a silicone double balloon cervical ripening catheter that rapidly controlled hemorrhage in a patient that failed conservative management with methotrexate. PMID:28261511

  20. Experimental investigation of undesired stable equilibria in pumpkin shape super-pressure balloon designs (United States)

    Schur, W. W.


    Excess in skin material of a pneumatic envelope beyond what is required for minimum enclosure of a gas bubble is a necessary but by no means sufficient condition for the existence of multiple equilibrium configurations for that pneumatic envelope. The very design of structurally efficient super-pressure balloons of the pumpkin shape type requires such excess. Undesired stable equilibria in pumpkin shape balloons have been observed on experimental pumpkin shape balloons. These configurations contain regions with stress levels far higher than those predicted for the cyclically symmetric design configuration under maximum pressurization. Successful designs of pumpkin shape super-pressure balloons do not allow such undesired stable equilibria under full pressurization. This work documents efforts made so far and describes efforts still underway by the National Aeronautics and Space Administration's Balloon Program Office to arrive on guidance on the design of pumpkin shape super-pressure balloons that guarantee full and proper deployment.

  1. Vessel wall temperature estimation for novel short term thermal balloon angioplasty: study of thermal environment. (United States)

    Kaneko, Kenji; Nakatani, Eriko; Futami, Hikaru; Ogawa, Yoshifumi; Arai, Tsunenori; Fukui, Masaru; Shimamura, Satoshi; Kawabata, Takashi


    We have been proposing novel thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PT-DBA). PTDBA realized thermal injury and low pressure dilatation that can prevent restenosis in chronic phase. We aim to determine the most efficient heating condition suit to individual symptom with pre-operation thermal simulation. We analyzed the flow dynamics and heat convection inside the balloon, and investigated heat conduction of balloon film to establish the temperature estimation method among vessel wall. Compared with ex vivo temperature measurement experiment, we concluded that the factors need to be considered for the establishment would be the heat conduction of the flow inside PTDB, heat conduction at the balloon film, and contact thermal resistance between the balloon film and vessel wall.

  2. Early clinical outcome and complications related to balloon kyphoplasty

    Directory of Open Access Journals (Sweden)

    Martin Bergmann


    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

  3. Elliptic and magneto-elliptic instabilities

    Directory of Open Access Journals (Sweden)

    Lyra Wladimir


    Full Text Available Vortices are the fundamental units of turbulent flow. Understanding their stability properties therefore provides fundamental insights on the nature of turbulence itself. In this contribution I briely review the phenomenological aspects of the instability of elliptic streamlines, in the hydro (elliptic instability and hydromagnetic (magneto-elliptic instability regimes. Vortex survival in disks is a balance between vortex destruction by these mechanisms, and vortex production by others, namely, the Rossby wave instability and the baroclinic instability.

  4. Five-millimeter balloon trocar site herniation: report of two cases and review of literature. (United States)

    Kanis, Margaux J; Momeni, Mazdak; Zakashansky, Konstantin; Chuang, Linus; Hayes, Monica Prasad


    Trocar site herniation is a well-known potential complication of minimally invasive surgery. We present the cases of two herniations after use of 5-mm non-bladed balloon trocars. In both patients, surgical management was required, with no subsequent sequelae to date. The hernias were attributed to excessive fascial stretching and compression by the balloon. We recommend full-thickness closure of 5-mm ports if a balloon is used or if there was extensive intraoperative manipulation.

  5. Sinus Balloon Dilation as Treatment for Acute Sphenoid Sinusitis with Impaired Vision for a Child

    Directory of Open Access Journals (Sweden)

    Yin Zhao


    Full Text Available This paper is about sinus balloon dilatation in treatment of acute left sphenoid sinusitis with left impaired vision in a child. Balloon catheter dilatation (BCD of the sinus ostia is a new technique. It has been shown to be a minimally invasive technique to manage chronic sinusitis. However, this method is rarely used in the treatment of acute sinusitis. So far, we know of no reported cases of sinus balloon dilatation in treatment of this case, especially for children.

  6. Planetary Balloon-Based Science Platform Evaluation and Program Implementation (United States)

    Dankanich, John W.; Kremic, Tibor; Hibbitts, Karl; Young, Eliot F.; Landis, Rob


    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

  7. 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


    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 ...

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

    CERN Document Server

    Nayak, A; Safonova, M; Murthy, Jayant


    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.

  9. 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)


    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.)

  10. Influence of inflation pressure and balloon size on the development of intimal hyperplasia after balloon angioplasty. A study in the atherosclerotic rabbit. (United States)

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


    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


    Institute of Scientific and Technical Information of China (English)


    @@ COARCTATION of the aorta (CoA) is a congenital heart defect involving a narrowing of the aorta. The narrowed segment called coarctation is most likely to happen in the segment just after the aortic arch. The narrowing can be removed by surgery or sometimes by a nonsurgical balloon dilation. However, aortic coarctation may recur even after successful surgery or balloon dilation. Fortunately, coarctation can now be treated with nonsurgical balloon dilation associated with implanting a stent using cardiac catheterization. Herein we reported our experience in a 19-year-old boy with CoA who underwent successful covered Cheatham-Platinum (CP) stent implantation for the coarctation.

  12. Interfacial instabilities and Kapitsa pendula (United States)

    Krieger, Madison


    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.

  13. Evaporative Instability in Binary Mixtures (United States)

    Narayanan, Ranga; Uguz, Erdem


    In this talk we depict the physics of evaporative convection for binary systems in the presence of surface tension gradient effects. Two results are of importance. The first is that a binary system, in the absence of gravity, can generate an instability only when heated from the vapor side. This is to be contrasted with the case of a single component where instability can occur only when heated from the liquid side. The second result is that a binary system, in the presence of gravity, will generate an instability when heated from either the vapor or the liquid side provided the heating is strong enough. In addition to these results we show the conditions at which interfacial patterns can occur. Support from NSF OISE 0968313, Partner Univ. Fund and a Chateaubriand Fellowship is acknowledged.

  14. Laboratory blast wave driven instabilities (United States)

    Kuranz, Carolyn


    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: [Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, San Francisco, CA 94143-1331 (United States)


    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


    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. Mechanical Instabilities of Biological Tubes (United States)

    Hannezo, Edouard; Prost, Jacques; Joanny, Jean-François


    We study theoretically the morphologies of biological tubes affected by various pathologies. When epithelial cells grow, the negative tension produced by their division provokes a buckling instability. Several shapes are investigated: varicose, dilated, sinuous, or sausagelike. They are all found in pathologies of tracheal, renal tubes, or arteries. The final shape depends crucially on the mechanical parameters of the tissues: Young’s 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.

  18. Political instability and illegal immigration. (United States)

    Campos, J E; Lien, D


    "Economic theory suggests that transnational migration results from the push-pull effect of wage differentials between host and source countries. In this paper, we argue that political instability exacerbates the migration flow, with greater instability leading to relatively larger flows. We conclude then that an optimal solution to the illegal immigration problem requires proper coordination of immigration and foreign policies by the host country. A narrow preoccupation with tougher immigration laws is wasteful and may be marginally effective." Emphasis is on the United States as a host country.

  19. Stringy bounces and gradient instabilities

    CERN Document Server

    Giovannini, Massimo


    Bouncing solutions are obtained from a generally covariant action characterized by a potential which is a nonlocal functional of the dilaton field at two separated space-time points. Gradient instabilities are shown to arise in this context but they are argued to be nongeneric. After performing a gauge-invariant and frame-invariant derivation of the evolution equations of the fluctuations, a heuristic criterium for the avoidance of pathological instabilities is proposed and corroborated by a number of explicit examples that turn out to be compatible with a quasi-flat spectrum of curvature inhomogeneities for typical wavelengths larger than the Hubble radius.

  20. Research on aviation fuel instability (United States)

    Baker, C. E.; Bittker, D. A.; Cohen, S. M.; Seng, G. T.


    The problems associated with aircraft fuel instability are discussed. What is currently known about the problem is reviewed and a research program to identify those areas where more research is needed is discussed. The term fuel instability generally refers to the gums, sediments, or deposits which can form as a result of a set of complex chemical reactions when a fuel is stored for a long period at ambient conditions or when the fuel is thermally stressed inside the fuel system of an aircraft.

  1. Undulation Instability of Epithelial Tissues

    CERN Document Server

    Basan, Markus; Prost, Jacques; Risler, Thomas; 10.1103/PhysRevLett.106.158101


    Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion.

  2. Modeling plaque fissuring and dissection during balloon angioplasty intervention. (United States)

    Gasser, T Christian; Holzapfel, Gerhard A


    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.

  3. Biogenic nonmethane hydrocarbon emissions estimated from tethered balloon observations (United States)

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


    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.

  4. BLAST: A balloon-borne, large-aperture, submillimetre telescope (United States)

    Wiebe, Donald Victor

    BLAST is a balloon-borne large-aperture, submillimetre telescope, which makes large area (1--200 square degree) surveys of Galactic and extragalactic targets. Since BLAST observes in the stratosphere, it is able to make broad-band observations between 200 mum and 550 mum which are difficult or impossible to perform from the ground. BLAST has been designed to probe star formation both in the local Galaxy and in the high redshift (z = 1--4) universe. Because BLAST is flown on an unmanned stratospheric balloon platform, it has been designed to be able to operate autonomously, without needing operator intervention to perform its scientific goals. This thesis includes an overview of the design of the BLAST platform, with emphasis on the command and control systems used to operate the telescope. BLAST has been flown on two long-duration balloon flights. The first of these, from Esrange, Sweden in June of 2005, acquired ˜70 hours of primarily Galactic data. During the second flight, from Willy Field, Antarctica in December of 2006, BLAST acquired ˜225 hours of both Galactic and extragalactic data. Operational performance of the platform during these two flights is reviewed, with the goal of providing insight on how future flights can be improved. Reduction of the data acquired by these large-format bolometer arrays is a challenging procedure, and techniques developed for BLAST data reduction are reviewed. The ultimate goal of this reduction is the generation of high quality astronomical maps which can be used for subsequent portions of data analysis. This thesis treats, in detail, the iterative, maximum likelihood map maker developed for BLAST. Results of simulations performed on the map maker to characterise its ability to reconstruct astronomical signals are presented. Finally, astronomical maps produced by this map maker using real data acquired by BLAST are presented, with a discussion on non-physical map pathologies resulting from the data reduction pipeline and

  5. Secondary instabilities of linearly heated falling films

    Institute of Scientific and Technical Information of China (English)

    HU Jun; SUN Dejun; HU Guohui; YIN Xieyuan


    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.

  6. Cineangiographic findings and balloon catheter angioplasty of pulmonic valvular stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Kyung Mo; Yoon, Yong Soo; Kim, In One; Han, Man Chung [College of Medicine, Seoul National University, Seoul (Korea, Republic of)


    Transluminal balloon valvuloplasty was performed in the treatment of congenital pulmonic valvular stenosis in 55 children, aged 4 months to 15 years. The right ventricular outflow tract pressure gradient decreased significantly immediately after the procedure from 87.18 {+-} 56mmHg to 29.62 {+-} 26.48mmHg ({rho} < 0.001). Technical success rate was 98% (54/55 patients) and failed case (1 patient) was due to severe fibrous thickening of valve. Complication occurred in one case, that is tricuspid regurgitation (Grade II) due to suspected rupture of chordae tendinae. The degree of pulmonary conus dilatation was closely related with age than the pressure gradient.

  7. 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


    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.

  8. Pointing system for the balloon-borne astronomical payloads (United States)

    Nirmal, Kaipacheri; Sreejith, Aickara Gopinathan; Mathew, Joice; Sarpotdar, Mayuresh; Ambily, Suresh; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant


    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, 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 real 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.

  9. Computing Optimum Heights for Balloon-Borne Radar (United States)


    ducting, a " radar hole" against other raytrace niodels (IREPS, could develop. Although the radar beam. EREPS) that are considered accurate. The may be...TD-1369, Naval Ocean Systems Center, San Diego, CA, October 1985. ,quires, M.F., Caribbean Basin Radar Network Raytrace Study, USAPETAC/PR-91/005...IlI-AFETAC/PR-93IoO5 * AD-A286 832 COMPUTING OPTIMUM HEIGHTS for BALLOON-BORNE RADAR by Michael F. Squires IjxEA NOVEMBER 1993 DTIC QUAI’ii E’T" 2T

  10. Balloon-borne observations of mid-latitude hydrofluoric acid (United States)

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


    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.

  11. Background Measurements from Balloon-Borne CZT Detectors


    Jenkins, Johnathan A; Narita, Tomohiko; Grindlay, Jonathan E.; Bloser, Peter F.; Stahle, Carl; Parker, Brad; Barthelmy, Scott


    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...

  12. Simulation of peeling-ballooning modes with pellet injection

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    Directory of Open Access Journals (Sweden)

    N. M. Gavrilov


    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

  14. Bakri balloon placement in the successful management of postpartum hemorrhage in a bicornuate uterus: A case report

    Directory of Open Access Journals (Sweden)

    Cynthia Abraham


    Conclusion: In the management of postpartum hemorrhage, Bakri balloon placement is associated with success in the presence of a bicornuate uterus. Care should be taken to direct insertion of the balloon in the appropriate location.

  15. Angiographic risk factors of luminal narrowing after coronary balloon angioplasty using balloon measurements to reflect stretch and elastic recoil at the dilation site. The CARPORT Study Group

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); J. Vos (Jeroen); K.J. Beatt (Kevin); P.M.M. Bossuyt (Patrick); W.R. Rutsch (Wolfgang); P.W.J.C. Serruys (Patrick)


    textabstractBecause many ongoing clinical restenosis prevention trials are using quantitative angiography to assess whether a drug is capable of reducing the amount of intimal hyperplasia, quantitative angiographic risk factors for angiographic luminal narrowing after balloon angioplasty were determ

  16. Angiographic risk factors of luminal narrowing after coronary balloon angioplasty using balloon measurements to reflect stretch and elastic recoil at the dilatation site

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); J. Vos (Jeroen); K.J. Beatt (Kevin); P.M.M. Bossuyt (Patrick); W.R. Rutsch (Wolfgang); P.W.J.C. Serruys (Patrick)


    textabstractAbstract Because many ongoing clinical restenosis prevention trials are using quantitative angiography to assess whether a drug is capable of reducing the amount of intimal hyperplasia, quantitative angiographic risk factors for angiographic luminal narrowing after balloon angioplasty

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

    Directory of Open Access Journals (Sweden)

    V. K. Balasubramanian


    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."

  18. 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


    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.

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

    Institute of Scientific and Technical Information of China (English)



    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,

  20. 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


    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.

  1. 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;


    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....

  2. Ureteropelvic junction obstruction and ureteral strictures treated by simple high-pressure balloon dilation

    DEFF Research Database (Denmark)

    Osther, P J; Geertsen, U; Nielsen, H V


    years, success was achieved in only 25% of cases. There were no major complications. It was concluded that simple high-pressure balloon dilation is a safe and reasonably effective technique for the management of most ureteral strictures and congenital UPJO with symptom debut in adult life. Balloon...... dilation seems to have no place in the treatment of primary congenital UPJO in children....

  3. Astronomy from the Upper Stratosphere: Key Discoveries and New Opportunities from High Altitude Scientific Balloons (United States)

    Fissel, Laura M.


    Stratospheric balloons offer a near-space astronomy platform for a small fraction of the cost of an equivalent satellite. These balloons can lift scientific payloads of up to 6,000 lbs as high as 40 km above the Earth’s surface (above >99.5% of the atmosphere). In this presentation I will discuss the contribution that scientific balloon experiments have made to astronomy, from the early days when astronomers had to accompany their telescopes to the stratosphere, to the present era where automated payloads are in some cases able to achieve a pointing precision of better than an arcsecond. In particular, I will discuss the important contributions that balloon telescopes have made to our current understanding of the Universe through detailed measurements of the Cosmic Microwave Background. I will also show how recent observations from sub-millimeter balloon telescopes such as BLAST and BLASTPol have been used to study both star formation and magnetic fields of nearby giant molecular clouds in unprecedented detail, and also to constrain models of interstellar dust composition. With improving ballooning technology, such as NASA’s new Super-Pressure Balloon program, we will soon have the capability for science flights of several months (rather than weeks) duration, thus beginning an exciting new era in balloon astronomy.


    Institute of Scientific and Technical Information of China (English)

    赵旻; 伍欣星; 邱小萍; 李晖; 戴天力; 谭云


    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. Waves and instabilities in plasmas

    CERN Document Server

    Chen Liu


    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.

  6. Lending sociodynamics and economic instability (United States)

    Hawkins, Raymond J.


    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.

  7. The Chemistry of Beer Instability (United States)

    Stewart, Graham G.


    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.

  8. Edge instabilities of topological superconductors (United States)

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


    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.

  9. 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


    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.

  10. An analysis of the deployment of a pumpkin balloon on mars (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

  11. 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


    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.

  12. Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms (United States)

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


    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.

  13. 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


    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.

  14. 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)


    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.

  15. Exhaled nitric oxide in mylar balloons: influence of storage time, humidity and temperature. (United States)

    Bodini, Alessandro; Pijnenburg, Mariëlle W H; Boner, Atillio L; de Jongste, Johan C


    BACKGROUND: Mylar balloons are used to collect exhaled air for analysis of fractional nitric oxide concentration (FENO). AIM: We studied the effect of storage conditions on the stability of nitric oxide (NO) in mylar balloons. METHODS: Exhaled air samples and calibration gases were stored in mylar balloons at 4, 21 and 37 degrees C, with or without silica gel. NO was measured after 0, 6, 9, 24 and 48 h. Scheffe F-tests were used to compare NO values. RESULTS: NO remained stable in balloons for 9 h at all temperatures, without silica gel. NO increased between 9 and 48 h, but only with low initial FENO. Silica gel increased variability. CONCLUSIONS: FENO in mylar balloons is stable for at least 9 h. The storage temperature is not critical, but silica gel increases variability. PMID:12745548

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

    Directory of Open Access Journals (Sweden)

    Natarajan M


    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.

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

    Directory of Open Access Journals (Sweden)

    Konstantinos Stamatiou


    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. Demonstration of a Balloon Borne Arc-second Pointer Design (United States)

    Deweese, K.; Ward, P.

    Many designs for utilizing stratospheric balloons as low-cost platforms on which to conduct space science experiments have been proposed throughout the years A major hurdle in extending the range of experiments for which these vehicles are useful has been the imposition of the gondola dynamics on the accuracy with which an instrument can be kept pointed at a celestial target A significant number of scientists have sought the ability to point their instruments with jitter in the arc-second range This paper presents the design and analysis of a stratospheric balloon borne pointing system that is able to meet this requirement The test results of a demonstration prototype of the design with similar ability are also presented Discussion of a high fidelity controller simulation for design analysis is presented The flexibility of the flight train is represented through generalized modal analysis A multiple controller scheme is utilized for coarse and fine pointing Coarse azimuth pointing is accomplished by an established pointing system with extensive flight history residing above the gondola structure A pitch-yaw gimbal mount is used for fine pointing providing orthogonal axes when nominally on target Fine pointing actuation is from direct drive dc motors eliminating backlash problems An analysis of friction nonlinearities and a demonstration of the necessity in eliminating static friction are provided A unique bearing hub design is introduced that eliminates static friction from the system dynamics A control scheme involving linear

  19. 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


    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...

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

    Directory of Open Access Journals (Sweden)

    Nogueira Júnior, João Flávio


    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.

  1. The response of superpressure balloons to gravity wave motions (United States)

    Vincent, R. A.; Hertzog, A.


    Superpressure balloons (SPB), which float on constant density (isopycnic) surfaces, provide a unique way of measuring the properties of atmospheric gravity waves (GW) as a function of wave intrinsic frequency. Here we devise a quasi-analytic method of investigating the SPB response to GW motions. It is shown that the results agree well with more rigorous numerical simulations of balloon motions and provide a better understanding of the response of SPB to GW, especially at high frequencies. The methodology is applied to ascertain the accuracy of GW studies using 12 m diameter SPB deployed in the 2010 Concordiasi campaign in the Antarctic. In comparison with the situation in earlier campaigns, the vertical displacements of the SPB were measured directly using GPS. It is shown using a large number of Monte Carlo-type simulations with realistic instrumental noise that important wave parameters, such as momentum flux, phase speed and wavelengths, can be retrieved with good accuracy from SPB observations for intrinsic wave periods greater than ca. 10 min. The noise floor for momentum flux is estimated to be ca. 10-4 mPa.

  2. The Balloon-borne Large Aperture Submillimeter Telescope: BLAST (United States)

    Truch, Matthew D. P.; Ade, P. A. R.; 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.; Pascale, E.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Thomas, N. E.; Tucker, C.; Tucker, G. S.; Viero, M. P.; Wiebe, D. V.


    The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a suborbital surveying 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 three arrays, observes simultaneously in broadband (30%) spectral windows at 250, 350, and 500 microns. The optical design is based on a 2 m diameter telescope, providing a diffraction-limited resolution of 30" at 250 microns. The gondola pointing system enables raster mapping of arbitrary geometry, with a repeatable positional accuracy of 30"; postflight pointing reconstruction to manual override. On this poster, we describe the primary characteristics and measured in-flight performance of BLAST. BLAST performed a test flight in 2003 and has since made two scientifically productive long-duration balloon flights: a 100 hour flight from ESRANGE (Kiruna), Sweden to Victoria Island, northern Canada in 2005 June; and a 250 hour, circumpolar flight from McMurdo Station, Antarctica in 2006 December. The BLAST collaboration acknowledges the support of NASA through grants NAG5-12785, NAG5-13301, and NNGO-6GI11G, the Canadian Space Agency (CSA), the Science and Technology Facilities Council (STFC), Canada's Natural Sciences and Engineering Research Council (NSERC), the Canada Foundation for Innovation, the Ontario Innovation Trust, the Puerto Rico Space Grant Consortium, the Fondo Institucional para la Investigacion of the University of Puerto Rico, and the National Science Foundation Office of Polar Programs.

  3. Beam tests of the balloon-borne ATIC experiment

    CERN Document Server

    Ganel, O; Ahn, H S; Ampe, J; Bashindzhagian, G L; Case, G; Chang, H; Ellison, S; Fazely, A; Gould, R; Granger, D; Gunasingha, R M; Guzik, T G; Han, Y J; Isbert, J; Kim, H J; Kim, K C; Kim, S K; Kwon, Y; Panasyuk, M Y; Panov, A; Price, B; Samsonov, G; Schmidt, W K H; Sen, M; Seo, E S; Sina, R; Sokolskaya, N; Stewart, M; Voronin, A; Wagner, D; Wang, J Z; Wefel, J P; Wu, J; Zatsepin, V


    The Advanced Thin Ionization Calorimeter (ATIC) balloon-borne experiment is designed to perform cosmic-ray elemental spectra measurements from 50 GeV to 100 TeV for nuclei from hydrogen to iron. These measurements are expected to provide information about some of the most fundamental questions in astroparticle physics today. ATIC's design centers on an 18 radiation length (X0) deep bismuth germanate (BGO) calorimeter, preceded by a 0.75λint graphite target. In September 1999, the ATIC detector was exposed to high-energy beams at CERN's SPS accelerator within the framework of the development program for the Advanced Cosmic-ray Composition Experiment for the Space Station (ACCESS). In December 2000–January 2001 and again in December 2002–January 2003, ATIC flew on the first two of a series of long-duration balloon (LDB) flights from McMurdo Station, Antarctica. We present here results from the 1999 beam tests, including energy resolutions for electrons and protons at several beam energies from 100 to 375 G...

  4. Linear Analysis of Drift Ballooning Modes in Tokamak Edge Plasmas (United States)

    Tangri, Varun; Kritz, Arnold; Rafiq, Tariq; Pankin, Alexei


    The H-mode pedestal structure depends on the linear stability of drift ballooning modes (DBMs) in many H-mode pedestal models. Integrated modeling that uses these pedestal models requires fast evaluation of linear stability of DBMs. Linear analysis of DBMs is also needed in the computations of effective diffusivities associated with anomalous transport that is driven by the DBMs in tokamak edge plasmas. In this study several numerical techniques of linear analysis of the DBMs are investigated. Differentiation matrix based spectral methods are used to compute the physical eigenvalues of the DBMs. The model for DBMs used here consists of six differential equations [T. Rafiq et al. Phys. Plasmas, 17, 082511, (2010)]. It is important to differentiate among non-physical (numerical) modes and physical modes. The determination of the number of eigenvalues is solved by a computation of the `nearest' and `ordinal' distances. The Finite Difference, Hermite and Sinc based differentiation matrices are used. It is shown that spectral collocation methods are more accurate than finite difference methods. The technique that has been developed for calculating eigenvalues is quite general and is relevant in the computation of other modes that utilize the ballooning mode formalism.

  5. 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


    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...

  6. Two cases of apical ballooning syndrome masking apical hypertrophic cardiomyopathy. (United States)

    Roy, Ranjini Raina; Hakim, Fayaz A; Hurst, R Todd; Simper, David; Appleton, Christopher P


    Apical akinesis and dilation in the absence of obstructive coronary artery disease is a typical feature of stress-induced (takotsubo) cardiomyopathy, whereas apical hypertrophy is seen in apical-variant hypertrophic cardiomyopathy. We report the cases of 2 patients who presented with takotsubo cardiomyopathy and were subsequently found to have apical-variant hypertrophic cardiomyopathy, after the apical ballooning from the takotsubo cardiomyopathy had resolved. The first patient, a 43-year-old woman with a history of alcohol abuse, presented with shortness of breath, electrocardiographic and echocardiographic features consistent with takotsubo cardiomyopathy, and no significant coronary artery disease. An echocardiogram 2 weeks later revealed a normal left ventricular ejection fraction and newly apparent apical hypertrophy. The 2nd patient, a 70-year-old woman with pancreatitis, presented with chest pain, apical akinesis, and a left ventricular ejection fraction of 0.39, consistent with takotsubo cardiomyopathy. One month later, her left ventricular ejection fraction was normal; however, hypertrophy of the left ventricular apex was newly noted. To our knowledge, these are the first reported cases in which apical-variant hypertrophic cardiomyopathy was masked by apical ballooning from stress-induced cardiomyopathy.

  7. The Use of Zylon Fibers in ULDB Balloons (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.

  8. Balloon-borne CALET prototype payload (bCALET) (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.

  9. Balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Irene Lang


    Full Text Available Chronic thromboembolic pulmonary hypertension (CTEPH is thought to result from incomplete resolution of pulmonary thromboemboli that undergo organisation into fibrous tissue within pulmonary arterial branches, filling pulmonary arterial lumina with collagenous obstructions. The treatment of choice is pulmonary endarterectomy (PEA in CTEPH centres, which has low post-operative mortality and good long-term survival. For patients ineligible for PEA or who have recurrent or persistent pulmonary hypertension after surgery, medical treatment with riociguat is beneficial. In addition, percutaneous balloon pulmonary angioplasty (BPA is an emerging option, and promises haemodynamic and functional benefits for inoperable patients. In contrast to conventional angioplasty, BPA with undersized balloons over guide wires exclusively breaks intraluminal webs and bands, without dissecting medial vessel layers, and repeat sessions are generally required. Observational studies report that BPA improves haemodynamics, symptoms and functional capacity in patients with CTEPH, but controlled trials with long-term follow-up are needed. Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. This review summarises the available evidence for BPA, patient selection, recent technical refinements and periprocedural imaging, and discusses the potential future role of BPA in the management of CTEPH.

  10. Computed Tomography During Experimental Balloon Dilatation For Calcific Aortic Stenosis. A Look into the Mechanism of Valvuloplasty

    NARCIS (Netherlands)

    C. di Mario (Carlo); L.C.P. van Veen; DE BAAT, L. (LEEN); C.E. Essed; K.J. Beatt (Kevin); O. Leborgne; SERRUYS, P.W. (PATRICK W.)


    textabstractThin‐slice contiguous computed tomographic scanning was performed in four postmortem hearts with calcific aortic valve stenosis (mean weight: 583 ± 78 g; mean age: 65 ± 10 years) before, during, and after balloon valvuloplasty. Balloons of increasing diameter (15–19 mm single balloons, a

  11. 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.

  12. 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


    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.

  13. Dose rate in intravascular radionuclide therapy using Re-188 coated balloon

    Energy Technology Data Exchange (ETDEWEB)

    Baek, M. Y.; Kim, J. K. [Hanyang Univ., Seoul (Korea, Republic of)


    Restenosis is the major drawback problem after percutaneous transluminal coronary angioplasty (PTCA). In order to reduce the restenosis, radionuclide therapy has been used, and these day balloon coating method with radionuclide is investigating to effective therapy. We intend to calculate the activity by Monte Carlo method, which is needed in the investigation of coated balloon using Re-188. We used EGSnrc code system to calculate this activity. Balloons were assumed be a length of 20 mm or 30 mm and to have a central catheter of diameter 0.5 mm. The surface of balloon is coated with 0.01 mm depth Re-188 using poly urethan. We calculated dose distribution as radial distance from the surface of balloon. And we calculate how much activities are needed to irradiate 18Gy at the 0.5 mm, 1.0 mm distance from balloon surface during 3 minutes. As results it is needed 19.3 mCi and 33.6 mCi relatively for each 0.5 mm and 1.0 mm in the 20 mm balloon. It is need 27.8 mCi and 48.3 mCi in the 30 mm balloon. Recent report for Ho-166 using EGS4 suggests 13.04 mCi at 0.5 mm distance in the 20 mm balloon. This value is lower than our result for Re-188 for the same size balloon. It is considered to be a systemic difference between two simulation codes ({approx}10%)

  14. 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


    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.

  15. Analogy between thermal convective and magnetohydrodynamic instabilities

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  16. Amplitude Equation for Instabilities Driven at Deformable Surfaces - Rosensweig Instability (United States)

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


    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.

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


    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

  18. Competing structural instabilities in cubic perovskites

    CERN Document Server

    Vanderbilt, D


    We study the antiferrodistortive instability and its interaction with ferroelectricity in cubic perovskite compounds. Our first-principles calculations show that coexistence of both instabilities is very common. We develop a first-principles scheme to study the thermodynamics of these compounds when both instabilities are present, and apply it to SrTiO$_3$. We find that increased pressure enhances the antiferrodistortive instability while suppressing the ferroelectric one. Moreover, the presence of one instability tends to suppress the other. A very rich $P$--$T$ phase diagram results.

  19. Collection of Stratospheric Samples using Balloon-Borne Payload System (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


    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

  20. On dynamical (black hole) instabilities

    CERN Document Server

    Coutant, Antonin; Parentani, Renaud


    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.

  1. Stretching Folding Instability and Nanoemulsions

    CERN Document Server

    Chan, Chon U


    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.

  2. Modern management of patellar instability. (United States)

    Rhee, Shin-Jae; Pavlou, George; Oakley, Jeremy; Barlow, David; Haddad, Farres


    Recurrent patellofemoral instability is a disabling condition, attributed to a variety of anatomical aetiologies. Trochlear dysplasia, patella alta, an increased tibial tubercle trochlear groove distance of greater than 20 mm and soft tissue abnormalities such as a torn medial patellofemoral ligament and inadequate vastus medialis obliquus are all factors to be considered. Management of this condition remains difficult and controversial and knowledge of the functional anatomy and biomechanics of the patellofemoral joint, a detailed history and clinical examination, and an accurate patient assessment are all imperative to formulate an appropriate management plan. Surgical treatment is based on the underlying anatomical pathology with an aim to restore normal patellofemoral kinematics. We summarise aspects of assessment, treatment and outcome of patellofemoral instability and propose an algorithm of treatment.

  3. Buckling instability of squeezed droplets

    CERN Document Server

    Elfring, Gwynn J


    Motivated by recent experiments, we consider theoretically the compression of droplets pinned at the bottom on a surface of finite area. We show that if the droplet is sufficiently compressed at the top by a surface, it will always develop a shape instability at a critical compression. When the top surface is flat, the shape instability occurs precisely when the apparent contact angle of the droplet at the pinned surface is pi, regardless of the contact angle of the upper surface, reminiscent of past work on liquid bridges and sessile droplets as first observed by Plateau. After the critical compression, the droplet transitions from a symmetric to an asymmetric shape. The force required to deform the droplet peaks at the critical point then progressively decreases indicative of catastrophic buckling. We characterize the transition in droplet shape using illustrative examples in two dimensions followed by perturbative analysis as well as numerical simulation in three dimensions. When the upper surface is not f...

  4. Streaming Instabilities in Protoplanetary Disks

    CERN Document Server

    Youdin, A N; Youdin, Andrew N.; Goodman, Jeremy


    Interpenetrating streams of solids and gas in a Keplerian disk produce a local, linear instability. The two components mutually interact via aerodynamic drag, which generates radial drift and triggers unstable modes. The secular instability does not require self-gravity, yet it generates growing particle density perturbations that could seed planetesimal formation. Growth rates are slower than dynamical, but faster than radial drift, timescales. Growth rates, like streaming velocities, are maximized for marginal coupling (stopping times comparable dynamical times). Fastest growth occurs when the solid to gas density ratio is order unity and feedback is strongest. Curiously, growth is strongly suppressed when the densities are too nearly equal. The relation between background drift and wave properties is explained by analogy with Howard's semicircle theorem. The three-dimensional, two-fluid equations describe a sixth order (in the complex frequency) dispersion relation. A terminal velocity approximation allows...

  5. Nonlinear evolution of drift instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.W.; Krommes, J.A.; Oberman, C.R.; Smith, R.A.


    The nonlinear evolution of collisionless drift instabilities in a shear-free magnetic field has been studied by means of gyrokinetic particle simulation as well as numerical integration of model mode-coupling equations. The purpose of the investigation is to identify relevant nonlinear mechanisms responsible for the steady-state drift wave fluctuations. It is found that the saturation of the instability is mainly caused by the nonlinear E x B convection of the resonant electrons and their associated velocity space nonlinearity. The latter also induces energy exchange between the competing modes, which, in turn, gives rise to enhanced diffusion. The nonlinear E x B convection of the ions, which contributes to the nonlinear frequency shift, is also an important ingredient for the saturation.

  6. Circulation in blast driven instabilities (United States)

    Henry de Frahan, Marc; Johnsen, Eric


    Mixing in many natural phenomena (e.g. supernova collapse) and engineering applications (e.g. inertial confinement fusion) is often initiated through hydrodynamic instabilities. Explosions in these systems give rise to blast waves which can interact with perturbations at interfaces between different fluids. Blast waves are formed by a shock followed by a rarefaction. This wave profile leads to complex time histories of interface acceleration. In addition to the instabilities induced by the acceleration field, the rarefaction from the blast wave decompresses the material at the interface, further increasing the perturbation growth. After the passage of the wave, circulation circulation generated by the blast wave through baroclinic vorticity continues to act upon the interface. In this talk, we provide scaling laws for the circulation and amplitude growth induced by the blast wave. Numerical simulations of the multifluid Euler equations solved using a high-order accurate Discontinuous Galerkin method are used to validate the theoretical results.

  7. Instability of supersymmetric microstate geometries

    CERN Document Server

    Eperon, Felicity C; Santos, Jorge E


    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.

  8. Mechanical Instabilities of Biological Tubes

    CERN Document Server

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


    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.

  9. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth


    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.

  10. Placing Marangoni instabilities under arrest

    CERN Document Server

    Bhamla, M Saad


    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.

  11. Cardiac Magnetic Resonance Imaging in the Diagnosis of Anterolateral Left Ventricular Ballooning, a Variant of Classic Takotsubo Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    R. Zbinden


    Full Text Available Transient left ventricular apical ballooning syndrome is characterized by transient akinesis of the left ventricular apex with basal wall hyperkinesis; this is also known as Takotsubo cardiomyopathy. There are three distinct contractile LV patterns described in the literature: apical, midventricular, and basal ballooning. The apical ballooning pattern is the most frequent pattern. We describe the case of a transient anterolateral left ventricular ballooning fulfilling the definition of Takotsubo cardiomyopathy except for the contractile LV pattern. The diagnosis was supported by cardiac magnetic resonance imaging and by the fact that the anterolateral ballooning resolved completely after 6 weeks.

  12. The use of a cutting balloon in contemporary reverse controlled antegrade and retrograde subintimal tracking (reverse CART) technique. (United States)

    Nakabayashi, Keisuke; Okada, Hisayuki; Oka, Toshiaki


    The key concept of reverse controlled antegrade and retrograde tracking (CART) technique is retrograde puncture with a tapered wire to an antegrade balloon (contemporary reverse CART) or new connections between the antegrade and retrograde subintimal space (classical reverse CART). In our case, a 75-year-old man with severe chronic total occlusion of the right coronary artery, reverse CART with conventional balloons could not be accomplished. Externalization wiring was completed by contemporary reverse CART using a cutting balloon as an antegrade balloon to improve the fenestration force of the retrograde guidewire. Thus, the use of a cutting balloon for contemporary reverse CART might be promising.

  13. 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


    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.

  14. Polygonal instabilities on interfacial vorticities

    CERN Document Server

    Labousse, Matthieu


    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.

  15. Instability of colliding metastable strings

    Energy Technology Data Exchange (ETDEWEB)

    Hiramatsu, Takashi [Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics; Eto, Minoru [Yamagata Univ. (Japan). Dept. of Physics; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research


    We investigate the collision dynamics of two metastable strings which can be viewed as tube-like domain walls with winding numbers interpolating a false vacuum and a true vacuum. We find that depending on the relative angle and speed of two strings, instability of strings increases and the false vacuum is filled out by rapid expansion of the strings or of a remnant of the collision.

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

  17. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

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


    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.

  18. Gravitational instabilities in astrophysical fluids (United States)

    Tohline, Joel E.


    Over the past decade, the significant advancements that have been made in the development of computational tools and numerical techniques have allowed astrophysicists to begin to model accurately the nonlinear growth of gravitational instabilities in a variety of physical systems. The fragmentation or rotationally driven fission of dynamically evolving, self-gravitating ``drops and bubbles'' is now routinely modeled in full three-dimensional generality as we attempt to understand the behavior of protostellar clouds, rotating stars, galaxies, and even the primordial soup that defined the birth of the universe. A brief review is presented here of the general insights that have been gained from studies of this type, followed by a somewhat more detailed description of work, currently underway, that is designed to explain the process of binary star formation. A short video animation sequence, developed in conjunction with some of the research being reviewed, illustrates the basic-nature of the fission instability in rotating stars and of an instability that can arise in a massive disk that forms in a protostellar cloud.

  19. Balloon Study of the Global Circuit: Spatial Coherence and Correlation with Lightning Observations (United States)

    Holzworth, R. H.; Bering, E. A.; Kokorowski, M.; Reddell, B.; Kadokura, A.; Yamagishi, H.; Sato, N.; Ejiri, M.; Hirosawa, H.; Yamagami, T.; Torii, S.; Tohyama, F.; Nakagawa, M.; Okada, T.


    The second campaign of the Polar Patrol Balloon (PPB) experiment (2nd-PPB) was carried out at Syowa Station in Antarctica during 2002-2003. This paper will present the global circuit results from the 2nd-PPB experiment. In that experiment, three balloons were launched for the purpose of upper atmosphere physics observation (3 balloons). Payloads of these 3 flights were identical with each other, and were launched as close together in time as allowed by weather conditions to constitute a cluster of balloons during their flights. Such a ``Balloon Cluster'' is suitable to observe temporal evolution and spatial distribution of phenomena in the ionospheric regions and boundaries that the balloons traversed during their circumpolar trajectory. More than 20 days of simultaneous fair weather 3-axis electric field and stratospheric conductivity data were obtained at geomagnetic latitudes ranging from sub-auroral to the polar cap. Balloon separation varied from ˜60 to ˜500 km. This paper will present the global circuit observations with emphasis on the times of apparent spatial variation in the vertical fair weather field. This paper will also present stratospheric conductivity observations with emphasis on the temporal and spatial variations that were observed. Finally, the inferred current density will be compared with data from the WWLL (TOGA) lightning monitor experiment.

  20. Utility of a scoring balloon for a severely calcified lesion: bench test and finite element analysis. (United States)

    Kawase, Yoshiaki; Saito, Naritatsu; Watanabe, Shin; Bao, Bingyuan; Yamamoto, Erika; Watanabe, Hiroki; Higami, Hirooki; Matsuo, Hitoshi; Ueno, Katsumi; Kimura, Takeshi


    We aimed to investigate the effectiveness of a scoring balloon catheter in expanding a circumferentially calcified lesion compared to a conventional balloon catheter using an in vitro experiment setting and elucidate the underlying mechanisms of this ability using a finite element analysis. True efficacy of the scoring device and the underlying mechanisms for heavily calcified coronary lesions are unclear. We employed a Scoreflex scoring balloon catheter (OrbusNeich, Hong Kong, China). The ability of Scoreflex to dilate a calcified lesion was compared with a conventional balloon catheter using 3 different sized calcium tubes. The thickness of the calcium tubes were 2.0, 2.25, and 2.5 mm. The primary endpoints were the successful induction of cracks in the calcium tubes and the inflation pressures required for inducing cracks. The inflation pressure required for cracking the calcium tubes were consistently lower with Scoreflex (p finite element analysis revealed that the first principal stress applied to the calcified plaque was higher by at least threefold when applying the balloon catheter with scoring elements. A scoring balloon catheter can expand a calcified lesion with lower pressure than that of a conventional balloon. The finite element analysis revealed that the concentration of the stress observed in the outside of the calcified plaque just opposite to the scoring element is the underlying mechanism of the increased ability of Scoreflex to dilate the calcified lesion.

  1. LISA: a java API for performing simulations of trajectories for all types of balloons (United States)

    Conessa, Huguette


    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.

  2. NASA balloon: Aircraft ranging, data and voice experiment (United States)

    Wishna, S.; Hamby, C.; Reed, D.


    A series of tests to evaluate, at L-band, the ranging, voice, and data communications concepts proposed for the air traffic control experiment of the Applications Technology Satellite-F are described. The ground station facilities, balloon platforms and the aircraft were supplied by the European Space Research Organization. One ground simulation and two aircraft flights at low elevation angles were conducted. Even under high interference conditions good performance was obtained for both voice communications and side tone ranging. High bit errors occurred in the data channels resulting in false commands. As a result of the experience gained in operating the equipment in an aircraft environment several recommendations were made for improving the equipment performance.

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

    DEFF Research Database (Denmark)

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


    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...

  4. Probabilistic Motion Planning of Balloons in Strong, Uncertain Wind Fields (United States)

    Wolf, Michael T.; Blackmore, Lars; Kuwata, Yoshiaki; Fathpour, Nanaz; Elfes, Alberto; Newman, Claire


    This paper introduces a new algorithm for probabilistic motion planning in arbitrary, uncertain vector fields, with emphasis on high-level planning for Montgolfiere balloons in the atmosphere of Titan. The goal of the algorithm is to determine what altitude--and what horizontal actuation, if any is available on the vehicle--to use to reach a goal location in the fastest expected time. The winds can vary greatly at different altitudes and are strong relative to any feasible horizontal actuation, so the incorporation of the winds is critical for guidance plans. This paper focuses on how to integrate the uncertainty of the wind field into the wind model and how to reach a goal location through the uncertain wind field, using a Markov decision process (MDP). The resulting probabilistic solutions enable more robust guidance plans and more thorough analysis of potential paths than existing methods.

  5. 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)


    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}.

  6. Long distance cell communication using spherical tether balloons (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.

  7. SPIDER: A Balloon-borne Large-scale CMB Polarimeter

    CERN Document Server

    Crill, B P; Battistelli, E S; Benton, S; Bihary, R; Bock, J J; Bond, J R; Brevik, J; Bryan, S; Contaldi, C R; Dore, O; Farhang, M; Fissel, L; Golwala, S R; Halpern, M; Hilton, G; Holmes, W; Hristov, V V; Irwin, K; Jones, W C; Kuo, C L; Lange, A E; Lawrie, C; MacTavish, C J; Martin, T G; Mason, P; Montroy, T E; Netterfield, C B; Pascale, E; Riley, D; Ruhl, J E; Runyan, M C; Trangsrud, A; Tucker, C; Turner, A; Viero, M; Wiebe, D


    Spider is a balloon-borne experiment that will measure the polarization of the Cosmic Microwave Background over a large fraction of a sky at 1 degree resolution. Six monochromatic refracting millimeter-wave telescopes with large arrays of antenna-coupled transition-edge superconducting bolometers will provide system sensitivities of 4.2 and 3.1 micro K_cmb rt s at 100 and 150 GHz, respectively. A rotating half-wave plate will modulate the polarization sensitivity of each telescope, controlling systematics. Bolometer arrays operating at 225 GHz and 275 GHz will allow removal of polarized galactic foregrounds. In a 2-6 day first flight from Alice Springs, Australia in 2010, Spider will map 50% of the sky to a depth necessary to improve our knowledge of the reionization optical depth by a large factor.

  8. 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


    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.

  9. Investigation of source position uncertainties & balloon deformation in MammoSite brachytherapy on treatment effectiveness. (United States)

    Bensaleh, S; Bezak, E


    The MammoSite breast high dose rate brachytherapy is used in treatment of early-stage breast cancer. The tumour bed volume is irradiated with high dose per fraction in a relatively small number of fractions. Uncertainties in the source positioning and MammoSite balloon deformation will alter the prescribed dose within the treated volume. They may also expose the normal tissues in balloon proximity to excessive dose. The purpose of this work is to explore the impact of these two uncertainties on the MammoSite dose distribution in the breast using dose volume histograms and Monte Carlo simulations. The Lyman-Kutcher and relative seriality models were employed to estimate the normal tissues complications associated with the MammoSite dose distributions. The tumour control probability was calculated using the Poisson model. This study gives low probabilities for developing heart and lung complications. The probability of complications of the skin and normal breast tissues depends on the location of the source inside the balloon and the volume receiving high dose. Incorrect source position and balloon deformation had significant effect on the prescribed dose within the treated volume. A 4 mm balloon deformation resulted in reduction of the tumour control probability by 24%. Monte Carlo calculations using EGSnrc showed that a deviation of the source by 1 mm caused approximately 7% dose reduction in the treated target volume at 1 cm from the balloon surface. In conclusion, accurate positioning of the (192)Ir source at the balloon centre and minimal balloon deformation are critical for proper dose delivery with the MammoSite brachytherapy applicator. On the basis of this study, we suggest that the MammoSite treatment protocols should allow for a balloon deformation of < or = 2 mm and a maximum source deviation of < or = 1 mm.

  10. Clinical Usefulness of Bakri Balloon Tamponade in the Treatment of Massive Postpartum Uterine Hemorrhage. (United States)

    Nagai, Sayori; Kobayashi, Hiroaki; Nagata, Tomomi; Hiwatashi, Sayuri; Kawamura, Toshihiko; Yokomine, Daisaku; Orita, Yuji; Oki, Toshimichi; Yoshinaga, Mitsuhiro; Douchi, Tsutomu


    Intrauterine globe-shaped metreurynter tamponade has been used for some time to treat massive postpartum hemorrhage (PPH). More recently, the Bakri balloon has come into use to treat PPH. It is made of silicon, possesses a drainage lumen, and has a sausage-like spindle shape. The aim of the present study was to investigate the clinical usefulness of Bakri balloon tamponade for massive PPH. Subjects in the present study comprised 5 patients with uterine atony, 3 with placenta previa, and 2 with low-lying placenta. All patients exhibited massive PPH and resistance to conventional hemostatic managements. Bakri balloon tamponade was appliedto these 10 patients. The mean amounts of uterine bleeding (average ± SD) before and after Bakri insertion were2,732 ± 1,397 mL and 380 ± 376 mL, respectively. The median (third-first quartile ranges) volume of salineinflating the balloon was 200 mL (300-150 mL). The median (third-first quartile ranges) indwelling duration of Bakri balloon was 24 hours (24-11 hrs). The overall success rate of Bakri balloon tamponade was 90% (9/10).There were no cases of slipping out or complications regarding balloon placement. Our findings suggest that Bakri balloon tamponade may be applied to the treatment of massive PPH in uterine atony and placenta previa.The Bakri balloon appears to have the following merits: (1) easy insertion into the uterine cavity and low rate of slipping out, (2) proper conformability to the hemorrhagic area due to its spindle shape, (3) ability to monitor blood loss through the drainage lumen even after insertion.

  11. Static and quasi-static analysis of lobed-pumpkin balloon (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.

  12. Measurement of polar stratospheric NO2 from the 23rd and 24th Japanese Antarctic Research Expedition (JARE) balloon experiments (United States)

    Shibasaki, K.; Iwagami, N.; Ogawa, T.


    As a part of the Japanese activities of MAP in the Antarctica, balloon-borne measurements of the stratospheric NO2 profile were planned and carried out by the JARE 23rd and 24th wintering parties. Few results have been reported so far as the stratospheric NO2 profile at high latitude. There were no reported balloon measurements carried out in the Southern Hemisphere. Profiles are presented for the first balloon-borne measurement of the stratospheric NO2 in the Antarctica. Three balloons named JA21, JA25 and JA26 were launched from Syowa Station (69 deg S, 35.6 deg E) using 5000 cu. cm plastic balloons. JA21 balloon was launched on November 24, 1982, and JA25 and JA26 balloons on November 12 and 20, 1983, respectively.

  13. Analysis of actinic flux profiles measured from an ozonesonde balloon (United States)

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


    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.

  14. Coordinated weather balloon solar radiation measurements during a solar eclipse. (United States)

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


    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'.

  15. Coordinated weather balloon solar radiation measurements during a solar eclipse (United States)


    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

  16. Background measurements from balloon-born imaging CZT detectors (United States)

    Jenkins, Jonathan A.; Narita, Tomohiko; Grindlay, Jonathan E.; Bloser, Peter F.; Stahle, Carl M.; Parker, Bradford H.; Barthelmy, Scott D.


    We report detector characteristics and background measurements from two prototype imaging CdZnTe (CZT) detectors flown on a scientific balloon payload in May 2001. The detectors are both platinum-contact 10 mm × 10 mm × 5 mm CZT crystals, each with a 4 × 4 array of pixels tiling the anode. One is made from IMARAD horizontal Bridgman CZT, the other from eV Products high-pressure Bridgman CZT. 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 40o field-of-view collimator 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 previosu detectors. The detectors and instrumentation performed well in a 20-hour balloon flight on 23/24 May 2001. Although we discovered a significant instrumental background component in flight, it was possible to measure and subtract this component from the spectra. The resulting IMARAD detector background spectrum reaches ~5×10-3 counts cm-2s-1keV-1 at 100 keV and has a power-law index of ~2 at hgih energies. The eV Products detector has a similar spectrum, although there is more uncertainty in the enregy scale because of calibration complications.

  17. Radiofrequency balloon angioplasty. Rationale and proof of principle

    Energy Technology Data Exchange (ETDEWEB)

    Becker, G.J.; Lee, B.I.; Waller, B.F.; Barry, K.J.; Kaplan, J.; Connolly, R.; Dreesen, R.G.; Nardella, P.


    Post-angioplasty restenosis (PARS) in atherosclerotic lesions of medium and small arteries occurs in about one-third of cases in the first year following percutaneous transluminal angioplasty (PTA) (early PARS). PARS includes acute spasm, dissection with reclosure, elastic recoil, fibrocellular proliferative response, and progressive atheromatous disease. Fibrocellular proliferation (possibly initiated by platelet derived growth factor) is felt to be culpable in many cases of early PARS (months). Pharmacologic regimens, stents, and thermal welding of the intimal-medial cracks of PTA are among the interventions being developed to deal with PARS. Radiofrequency (RF) current as a source of thermal energy may be useful in combination with balloon angioplasty to reduce PARS. Ideally, this combination would (1) weld intimal-medial cracks of PTA; (2) mold plaque and normal vessel to increase lumen diameters without creating intimal-medial cracks; and (3) destroy medial smooth muscle cells and multipotential cells (cellular substrate of PARS). Canine in vivo studies have established the feasibility of RF-mediated vascular tissue welding. Human aortic specimens (N = 28) were manually dissected into intima-media and media-adventitia layers. Bipolar RF energy (650 KHz, total 300 J) and mechanical pressure (1 atm) (experimental group, N = 24) or mechanical pressure alone (control group, N = 4) were applied to the reapposed specimen layers in a special chamber. The chamber was modified with a bipolar electrode designed to reproduce that planned for an RF balloon angioplasty catheter. Welding was demonstrated in normal and atherosclerotic treated specimens (23/24 or 96%) but not controls (0/4).

  18. CNES super pressure balloons upgrade for Strateole-2 campaign (United States)

    Venel, Stephanie; Cocquerez, Philippe; Hertzog, Albert


    The French Space Agency, CNES, has developed, since about twelve years ago, super pressure balloons (SPB) that float on constant density (isopycnic) surfaces in the lowermost stratosphere, carrying 40 to 50 kg payloads, during typically three months. These SPB have been successfully deployed in flotilla of about 20 balloons for different scientific campaigns all over the world in different configuration sizes from 8,5 to 12 m diameter, mainly to document the chemistry and dynamics of the atmosphere, to study gravity waves, and to provide in-situ atmospheric profiles thanks to the NCAR driftsonde payload. The SPB housekeeping gondola used from 2005 to 2011 now needs to be upgraded in order to increase the flights' safety and to improve its performance with up to date equipment's. The control center will also be redesigned. These modifications take into account the experience acquired during the last SPB campaigns, mainly during CONCORDIASI, with 19 flights over Antarctica from September 2010 to January 2011. After a successful preliminary design review, the project is now conducting the detailed conception phase. This new system is developed for STRATEOLE-2, a project dedicated to the coupling processes between the troposphere and the stratosphere in the deep tropics, using several types of instruments, both for in situ and remote measurements in the atmosphere. STRATEOLE -2 includes two measurement campaigns, three years spaced to study the quasi biennial oscillation. Since the scientific payloads are fully self-standing, some technical solutions will be common with the CNES housekeeping gondola, such as the renewable power system. This paper will describe the STRATEOLE-2 project and the developments in progress for the SPB system upgrade.

  19. Current diffusive ballooning mode in a Tokamak with a noncircular cross section

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masatoshi; Itoh, Sanae [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics; Fukuyama, Atsushi; Itoh, Kimitaka


    The eigenvalue equation for the current diffusive ballooning mode in tokamaks is derived taking the geometrical effects, i.e., triangularity and ellipticity into account. The stability boundary is obtained in the strong ballooning limit. It is found that the ellipticity plays an important role on the stability of the current diffusive ballooning mode. On the other hand, the effect of the stabilization by the triangularity appears indirectly through the magnetic well term. The geometrical effect on the transport coefficient is also discussed. (author)

  20. Balloon occlusion of the internal iliac arteries in the multidisciplinary management of placenta percreta

    DEFF Research Database (Denmark)

    Clausen, Caroline; Stensballe, Jakob; Albrechtsen, Charlotte K;


    Objective. To evaluate our experience with prophylactic balloon occlusion of the internal iliac arteries as a part of a multidisciplinary algorithm for the management of placenta percreta. Design. Consecutive case series. Setting. Rigshospitalet, Copenhagen University Hospital, Denmark. Sample....... Prophylactic balloon occlusion of the internal iliac arteries as part of a multidisciplinary algorithm allowed for a safe management of all cases in our consecutive series of 17 women with placenta percreta. However, intraoperative blood loss and transfusion requirements were significant. We have therefore...... decided to modify our multidisciplinary algorithm to include balloon occlusion of the common iliac arteries rather than the internal iliac arteries....

  1. Modes of storage ring coherent instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.M.


    Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered. (LEW)

  2. Compressor instability with integral methods

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Y.K. Eddie [Nanyang Technological Univ., Singapore (Singapore). School of Mechanical and Aerospace Engineering; Liu, Ningyu [Singapore National Univ. (Singapore). Dept. of Mechanical Engineering


    ''Compressor Instability with Integral Methods'' is a book, to bring together the quick integral approaches and advances in the field for the prediction of stall and surge problem in compressor. This book is useful for people involved in the flow analysis, design and testing of rotating machinery. For students, it can be used as a specialized topic of senior undergraduate or graduate study. The book can also be served as a self-study material to those who keen to acquire this knowledge. In brief, this book focuses on the numerical/computational analysis for the effect of distorted inlet flow propagation on the rotating stall and surge in axial compressors. It gains insight into the basic phenomena controlling these flow instabilities, and reveals the influence of inlet parameters on rotating stall and surge. The book starts from the confirmation and application of Kim et al's integral method and then follows by a development to this method through the proposing and applying a critical distortion line. This line is applied successfully on the stall prediction of in-flight compressor due to flaming of refueling leakage near inlet, a typical real and interesting example of compressor stall and surge operation. Further, after a parametric study on the integral method and the distorted flow field of compressor using Taguchi method, a novel integral method is formulated using more appropriate and practical airfoil characteristics, with a less assumptions needed for derivation. Finally, as an extended work, the famous Greitzer's instability flow model, the well-known B-parameter model applied for analyzing the stall and surge characteristics, is studied parametrically using Taguchi method. (orig.)

  3. Demonstrating Classical Conditioning in Introductory Psychology: Needles Do Not Always Make Balloons Pop! (United States)

    Vernoy, Mark W.


    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)

  4. Optical coherence tomography layer thickness characterization of a mock artery during angioplasty balloon deployment (United States)

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


    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.

  5. EUSO-BALLOON a pathfinder for detecting UHECR's from the edge of space

    Directory of Open Access Journals (Sweden)

    Scotti V.


    Full Text Available EUSO-Balloon has been conceived as a pathfinder mission for JEM-EUSO, to perform an end-to-end test of the subsystems and components, and to prove the global detection chain while improving our knowledge of the atmospheric and terrestrial UV background. Through a series of stratospheric balloon flights performed by the French Space Agency CNES, EUSO-BALLOON will serve as an evolutive test-bench for all the key technologies of JEM-EUSO. EUSO-Balloon also has the potential to detect Extensive Air Showers from above, marking a key milestone in the development of UHECR science, and paving the way for any future large scale, space-based UHECR observatory.

  6. Balloon-Borne, High-Energy Astrophysics: Experiences from the 1960s to the 1980s (United States)

    Fishman, Gerald J.


    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.

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

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

  9. Integrating BalloonSAT and Atmospheric Dynamic Concepts into the Secondary Classroom (United States)

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


    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.

  10. Spatiotemporal chaos involving wave instability (United States)

    Berenstein, Igal; Carballido-Landeira, Jorge


    In this paper, we investigate pattern formation in a model of a reaction confined in a microemulsion, in a regime where both Turing and wave instability occur. In one-dimensional systems, the pattern corresponds to spatiotemporal intermittency where the behavior of the systems alternates in both time and space between stationary Turing patterns and traveling waves. In two-dimensional systems, the behavior initially may correspond to Turing patterns, which then turn into wave patterns. The resulting pattern also corresponds to a chaotic state, where the system alternates in both space and time between standing wave patterns and traveling waves, and the local dynamics may show vanishing amplitude of the variables.

  11. Nonlinear Instability of Liquid Layers. (United States)

    Newhouse, Lori Ann

    The nonlinear instability of two superposed viscous liquid layers in planar and axisymmetric configurations is investigated. In the planar configuration, the light layer fluid is bounded below by a wall and above by a heavy semiinfinite fluid. Gravity drives the instability. In the first axisymmetric configuration, the layer is confined between a cylindrical wall and a core of another fluid. In the second, a thread is suspended in an infinite fluid. Surface tension forces drive the instability in the axisymmetric configurations. The nonlinear evolution of the fluid-fluid interface is computed for layers of arbitrary thickness when their dynamics are fully coupled to those of the second fluid. Under the assumption of creeping flow, the flow field is represented by an interfacial distribution of Green's functions. A Fredholm integral equation of the second kind for the strength of the distribution is derived and then solved using an iterative technique. The Green's functions produce flow fields which are periodic in the direction parallel to the wall and have zero velocity on the wall. For small and moderate surface tension, planar layers evolve into a periodic array of viscous plumes which penetrate into the overlying fluid. The morphology of the plumes depends on the surface tension and the ratio of the fluid viscosities. As the viscosity of the layer increases, the plumes change from a well defined drop on top of a narrow stem to a compact column of rising fluid. The capillary instability of cylindrical interfaces and interfaces in which the core thickness varies in the axial direction are investigated. In both the unbounded and wall bounded configurations, the core evolves into a periodic array of elongated fluid drops connected by thin, almost cylindrical fluid links. The characteristics of the drop-link structure depend on the core thickness, the ratio of the core radius to the wall radius, and the ratio of the fluid viscosities. The factors controlling the

  12. Bathtub vortex induced by instability (United States)

    Mizushima, Jiro; Abe, Kazuki; Yokoyama, Naoto


    The driving mechanism and the swirl direction of the bathtub vortex are investigated by the linear stability analysis of the no-vortex flow as well as numerical simulations. We find that only systems having plane symmetries with respect to vertical planes deserve research for the swirl direction. The bathtub vortex appearing in a vessel with a rectangular cross section having a drain hole at the center of the bottom is proved to be induced by instability when the flow rate exceeds a threshold. The Coriolis force is capable of determining the swirl direction to be cyclonic.

  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


    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. 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


    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.

  15. Optimal excitation of two dimensional Holmboe instabilities

    CERN Document Server

    Constantinou, Navid C


    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 ...

  16. Mode-locking via dissipative Faraday instability (United States)

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


    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.

  17. Mode-locking via dissipative Faraday instability. (United States)

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


    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. Expression of glutamine synthetase in balloon cells: a basis of their antiepileptic role? (United States)

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


    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.

  19. 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


    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.

  20. Balloon-assisted guide catheter positioning to overcome extreme cervical carotid tortuosity: technique and case experience


    Peeling, Lissa; Fiorella, David


    Background and significance We describe a method by which to efficiently and atraumatically achieve distal positioning of a flexible guiding catheter beyond extreme cervical tortuosity using a hypercompliant temporary occlusion balloon. Methods A retrospective review of a prospective neuroendovascular database was used to identify cases in which a hypercompliant balloon catheter (Hyperform or Hyperglide, ev3/Covidien, Irvine, California, USA; Scepter or Scepter XC, Alisa Viejo, California, US...

  1. A New Type of Captive Balloon for Vertical Meteorological Observation in Urban Area (United States)

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


    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.

  2. 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


    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...

  3. Balloon-guided navigation technique to perform stenting in an acutely angled anterior cerebral artery. (United States)

    Cohen, José E; Gomori, John M; Moscovici, Samuel; Itshayek, Eyal


    The complex anatomic features of wide-necked anterior communicating artery aneurysms represent an endovascular challenge. Compliant balloons and microstents are frequently required to achieve aneurysm occlusion. When the angle between the A1 and A2 segments is acute, microcatheter navigation is hazardous, and may be difficult or sometimes impossible with standard techniques. We present our technique using a support balloon to facilitate guidewire engagement and navigation of A2, and to assist with microcatheterization in this unfavorable vascular anatomy.

  4. Current-diffusive ballooning mode in low shear and negative shear regions of tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masatoshi; Azumi, Masafumi (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment); Itoh, Kimitaka; Itoh, Sanae; Fukuyama, Atsushi


    The stability of the current-diffusive ballooning mode in tokamaks with high toroidal mode number is analyzed in the region of second stability against the ideal magnetohydrodynamic mode. It is found that the growth rate of the current-diffusive ballooning mode is decreased upon the reduction of the geodesic curvature driving force. The reduction of thermal conductivity in the limit of very weak shear or negative shear in comparison with standard shear is also shown. (author).

  5. Drug-Coated Balloon Treatment of Very Late Stent Thrombosis Due to Complicated Neoatherosclerosis (United States)

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


    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

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


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


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

  7. Drug-eluting balloon catheters for lower limb peripheral arterial disease: the evidence to date

    Directory of Open Access Journals (Sweden)

    Barkat M


    Full Text Available Mohamed Barkat,1 Francesco Torella,1 George A Antoniou2 1Liverpool Vascular and Endovascular Service, Royal Liverpool University Hospital, Liverpool, 2Department of Vascular and Endovascular Surgery, The Royal Oldham Hospital, Pennine Acute Hospitals NHS Trust, Manchester, UK Abstract: A significant proportion of patients with severe lower limb peripheral arterial disease require revascularization. Over the past decade, an endovascular-first approach even for complex disease has gained widespread use among vascular specialists. An important limitation of percutaneous transluminal balloon angioplasty or stenting remains the occurrence of restenosis. Drug-coated balloons have emerged as an exciting technology developed to overcome the limitations of standard balloon angioplasty and stenting. Drug-eluting devices inhibit neointimal growth of vascular smooth muscle cells with the potential of preventing restenosis. This review provides a synopsis of the up-to-date evidence on the role of drug-coated balloons in the treatment of lower limb peripheral arterial disease. Bibliographic searches were conducted using MEDLINE, EMBASE, and the Cochrane Library electronic database. Eleven randomized clinical trials, two systematic reviews, and a published registry providing the best available evidence were identified. Current evidence suggests that angioplasty with drug-coated balloon is reliable, safe, and efficient in increasing patency rates and reducing target lesion revascularization and restenosis. However, it remains unknown whether these improved results can translate into beneficial clinical outcomes, as current randomized clinical trials have failed to demonstrate a significant benefit in limb salvage and mortality. Further randomized trials focusing on clinical and functional outcomes of drug-eluting balloons and on cost versus clinical benefit are required. Keywords: drug-eluting balloon, drug-coated balloon, angioplasty, peripheral arterial

  8. Limited endoscopic sphincterotomy plus large balloon dilation for choledocholithiasis with periampullary diverticula

    Institute of Scientific and Technical Information of China (English)

    Hyung; Wook; Kim; Dae; Hwan; Kang; Cheol; Woong; Choi; Jong; Hwan; Park; Jin; Ho; Lee; Min; Dae; Kim; Il; Doo; Kim; Ki; Tae; Yoon; Mong; Cho; Ung; Bae; Jeon; Suk; Kim; Chang; Won; Kim; Jun; Woo; Lee


    AIM: To investigate the effectiveness and safety of limited endoscopic sphincterotomy (EST) plus large balloon dilation (LBD) for removing choledocholithiasis in patients with periampullary diverticula (PAD). METHODS: A total of 139 patients with common bile duct (CBD) stones were treated with LBD (10-20 mm balloon diameter) after limited EST. Of this total, 73 patients had PAD and 66 patients did not have PAD (controls). The results of stone removal and complications were retrospectively evaluated. RESULTS...

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  10. FIREBALL: the Faint Intergalactic medium Redshifted Emission Balloon: overview and first science flight results


    Milliard, Bruno; Martin, D. Christopher; Schiminovich, David; Evrard, Jean; Matuszewski, Matt; Rahman, Shahinur; Tuttle, Sarah; McLean, Ryan; Deharveng, Jean-Michel; Mirc, Frederi; Grange, Robert; Chave, Robert


    FIREBALL (the Faint Intergalactic Redshifted Emission Balloon) is a balloon-borne 1m telescope coupled to an ultraviolet fiber-fed spectrograph. FIREBALL is designed to study the faint and diffuse emission of the intergalactic medium, until now detected primarily in absorption. FIREBALL is a path finding mission to test new technology and make new constraints on the temperature and density of this gas. We report on the first successful science flight of FIREBALL, in June 2009, which proved ev...

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

    Directory of Open Access Journals (Sweden)

    A. Gallice


    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.

  12. 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.


    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.

  13. Fishbone Instability Excited by Barely Trapped Electrons

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-Tian; LONG Yong-Xing; DONG Jia-Qi; WANG Long; Fulvio Zonca


    Fishbone instability excited by barely trapped suprathermal electrons (BTSEs) in tokamaks is investigated theoretically. The frequency of the mode is found to close to procession frequency of BTSEs. The growth rate of the mode is much smaller than that of the ideal magnetohytrodynamic (MHD) internal kink mode that is in contrast to the case of trapped ion driven fishbone instability. The analyses also show that spatial density gradient reversal is necessary for the instability. The correlation of the results with experiments is discussed.

  14. Electron proton instability in the CSNS ring

    Institute of Scientific and Technical Information of China (English)

    WANG Na; QIN Qing; LIU Yu-Dong


    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).

  15. Beam Instabilities in the Scale Free Regime

    CERN Document Server

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


    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.

  16. Instabilities and transition in boundary layers

    Indian Academy of Sciences (India)

    N Vinod; Rama Govindarajan


    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.

  17. Balloon-expandable covered stent therapy of complex endovascular pathology. (United States)

    Giles, Heath; Lesar, Christopher; Erdoes, Luke; Sprouse, Richard; Myers, Stuart


    The current study was designed to investigate our hypotheses that balloon-expandable covered stents display acceptable function over longitudinal follow-up in patients with complex vascular pathology and provide a suitable alternative for the treatment of recurrent in-stent restenosis. All stents were Atrium iCast, which is a balloon-mounted, polytetrafluoroethylene-covered stent with a 6F/7F delivery system. A retrospective review was performed of 49 patients with 66 stented lesions. Data were analyzed with life tables and t-tests. The most commonly treated vessels were the iliac (61%) and renal (24%) arteries. Indications for covered stent placement were unstable atheromatous lesions (50%), recurrent in-stent restenosis (24%), aneurysm (8%), aortic bifurcation reconstruction (7.5%), dissection (4.5%), endovascular aneurysm repair-related (4.5%), and stent fracture (1.5%). Patency was assessed by angiogram or duplex ultrasonography. The primary end point was patency and secondary end points were technical success and access-site complications. Mean follow-up was 13 months (range 1.5-25). The technical success rate was 97%. Unsuccessful outcomes were due to deployment error (n=1) and stent malpositioning (n=1). The cohort (n=64) 6- and 12-month primary patency rates were 96% and 84%, respectively. Twelve-month assisted primary patency was 98%. Iliac artery stents (n=38) had a primary patency of 97% at 6 months and 84% at 12 months with an assisted primary patency of 100% at 12 months. Renal artery stents (n=16) had a primary patency of 92% at 6 months and 72% at 12 months with an assisted primary patency of 92% at 6 and 12 months. Stents placed for recurrent in-stent restenosis (n=16) had a primary patency of 85%, assisted primary patency of 93%, and a 15% restenosis rate at 12 months. Specifically, stents placed for renal artery recurrent in-stent restenosis (n=10) had a primary patency of 73%, assisted primary patency of 82%, and a restenosis rate of 27%. The

  18. [Cervical spine instability in the surgical patient]. (United States)

    Barbeito, A; Guerri-Guttenberg, R A


    Many congenital and acquired diseases, including trauma, may result in cervical spine instability. Given that airway management is closely related to the movement of the cervical spine, it is important that the anesthesiologist has detailed knowledge of the anatomy, the mechanisms of cervical spine instability, and of the effects that the different airway maneuvers have on the cervical spine. We first review the normal anatomy and biomechanics of the cervical spine in the context of airway management and the concept of cervical spine instability. In the second part, we review the protocols for the management of cervical spine instability in trauma victims and some of the airway management options for these patients.

  19. Systems and methods for controlling flame instability

    KAUST Repository

    Cha, Min Suk


    A system (62) for controlling flame instability comprising: a nozzle (66) coupled to a fuel supply line (70), an insulation housing (74) coupled to the nozzle, a combustor (78) coupled to the nozzle via the insulation housing, where the combustor is grounded (80), a pressure sensor (82) coupled to the combustor and configured to detect pressure in the combustor, and an instability controlling assembly coupled to the pressure sensor and to an alternating current power supply (86), where, the instability controlling assembly can control flame instability of a flame in the system based on pressure detected by the pressure sensor.

  20. 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


    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

  1. Aeroelastic instability problems for wind turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig


    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....

  2. Two-Fluid Interface Instability Being Studied (United States)

    Niederhaus, Charles E.


    The interface between two fluids of different density can experience instability when gravity acts normal to the surface. The relatively well known Rayleigh-Taylor (RT) instability results when the gravity is constant with a heavy fluid over a light fluid. An impulsive acceleration applied to the fluids results in the Richtmyer-Meshkov (RM) instability. The RM instability occurs regardless of the relative orientation of the heavy and light fluids. In many systems, the passing of a shock wave through the interface provides the impulsive acceleration. Both the RT and RM instabilities result in mixing at the interface. These instabilities arise in a diverse array of circumstances, including supernovas, oceans, supersonic combustion, and inertial confinement fusion (ICF). The area with the greatest current interest in RT and RM instabilities is ICF, which is an attempt to produce fusion energy for nuclear reactors from BB-sized pellets of deuterium and tritium. In the ICF experiments conducted so far, RM and RT instabilities have prevented the generation of net-positive energy. The $4 billion National Ignition Facility at Lawrence Livermore National Laboratory is being constructed to study these instabilities and to attempt to achieve net-positive yield in an ICF experiment.

  3. Instabilities of flows and transition to turbulence

    CERN Document Server

    Sengupta, Tapan K


    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

  4. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Aliye Filiz


    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.

  6. Long-term outcomes of balloon dilation for acquired subglottic stenosis in children. (United States)

    Filiz, Aliye; Ulualp, Seckin O


    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.

  7. Integrating Balloon and Satellite Operation Data Centers for Technology Readiness Assessment (United States)

    Mattiello-Francisco, Fátima; Fernandes, Jose Oscar


    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.

  8. Drug-eluting balloon catheters for lower limb peripheral arterial disease: the evidence to date (United States)

    Barkat, Mohamed; Torella, Francesco; Antoniou, George A


    A significant proportion of patients with severe lower limb peripheral arterial disease require revascularization. Over the past decade, an endovascular-first approach even for complex disease has gained widespread use among vascular specialists. An important limitation of percutaneous transluminal balloon angioplasty or stenting remains the occurrence of restenosis. Drug-coated balloons have emerged as an exciting technology developed to overcome the limitations of standard balloon angioplasty and stenting. Drug-eluting devices inhibit neointimal growth of vascular smooth muscle cells with the potential of preventing restenosis. This review provides a synopsis of the up-to-date evidence on the role of drug-coated balloons in the treatment of lower limb peripheral arterial disease. Bibliographic searches were conducted using MEDLINE, EMBASE, and the Cochrane Library electronic database. Eleven randomized clinical trials, two systematic reviews, and a published registry providing the best available evidence were identified. Current evidence suggests that angioplasty with drug-coated balloon is reliable, safe, and efficient in increasing patency rates and reducing target lesion revascularization and restenosis. However, it remains unknown whether these improved results can translate into beneficial clinical outcomes, as current randomized clinical trials have failed to demonstrate a significant benefit in limb salvage and mortality. Further randomized trials focusing on clinical and functional outcomes of drug-eluting balloons and on cost versus clinical benefit are required. PMID:27274265


    Directory of Open Access Journals (Sweden)

    P. Akbari Asbagh A. Shahmohammadi


    Full Text Available Soon after successful results of balloon valvuloplasty in treatment of congenital pulmonary stenosis, use of this technique for relief of congenital aortic stenosis (AS was attempted in different parts of the world. With the purpose of assessment the value of valvuloplasty in comparison with surgical valvotomy in relief of congenital AS, we retrospectively studied 115 patients with valvar AS, 48 of whom underwent balloon valvuloplasty (mean age 9.63 years, and 67 subjected to surgical aortic valvotomy (mean age 10.32 years, in a six year period from 1991 to 1997 at Rajaie heart hospital. Comparison of balloon valvuloplasty with surgical valvotomy revealed that reduction in the mean pressure gradient in balloon valvuloplasty group was greater than those subjected to surgical valvotomy (73.54 vs. 45.03 mmHg, P < 0.0001. Decreased incidence of aortic insufficiency and mortality in balloon valvuloplasty in comparison with surgical valvotomy are other notable points in this study. Although it is difficult to compare the results of the two procedures and determine their different indications, our successful experience with balloon valvuloplasty for congenital AS and the safety of this procedure encourage us to use this technique for the patients with congenital AS more than ever. These results must be supported by future studies.

  10. [A new balloon-expandable plastic endoprosthesis. Initial report of experience with the malleable thermostent]. (United States)

    Beck, A


    A new system of balloon-expandable stents for different purposes is presented. A special plastic material that can be shaped by a hot balloon technique or other internal or external heating modalities has been developed. The plastic material - a distant derivative of polyurethane - is caprolactone, which is soft from 52 degrees C to 70 degrees C. Using balloon techniques, the "thermo-stent" can be modeled to suit the form of the vessels, the bile ducts or the bronchial tree, as required. The balloon can be heated simply by means of a warm NaCl solution, electric matter in the balloon itself or microwaves. The plastic material can even be heated directly, which is especially beneficial if the stent needs to be thicker, e.g. in the bronchial tree, by an electric network within the plastic material, which heats the material to the necessary temperature by electric current. When the balloon is cooled after the dilatation the new form, the plastic has been modeled to is maintained exactly. The advantages of this thermo-stent will be the perfect adaptation to every individual situation in the intraluminal vessels, the bile ducts, and even the bronchi. The problems encountered hitherto with conventional metallic stents, e.g. high thrombogenicity, risk of metal intoxication or metallic rupture of filaments, have not be seen so far in animal experiments.

  11. Significant skin burns may occur with the use of a water balloon in HIFU treatment (United States)

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


    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.

  12. Status of balloon production for KamLAND-Zen 800 kg phase (United States)

    Obara, S.


    KamLAND-Zen is an experiment for neutrinoless double beta decay (0 ν 2 β) search with 136Xe, based on the large liquid scintillator detector KamLAND. KamLAND-Zen includes 16.5 m3 xenon loaded liquid scintillator in a 3.16 m diameter nylon balloon (inner-balloon) with 25 μm wall thickness. KamLAND-Zen 400 (383 kg 136Xe used) released a lower limit on the 0 ν 2 β half-life of 136Xe. However, the sensitivity is limited by the contamination of radioactive backgrounds from the inner-balloon. Then, we planned KamLAND-Zen 800, upgrading the detector with a new inner-balloon of 3.84 m diameter with 800 kg 136Xe and 31.4 m3 liquid scintillator. We present the current status of KamLAND-Zen, the new mini-balloon construction and methods to avoid background contaminations. In addition, the development of a scintillating balloon for future upgrades in order to remove the radioactive decay chain daughter nuclei bismuth is also introduced.

  13. Cosmic Rays and Radiative Instabilities

    CERN Document Server

    Hartquist, T W; Falle, S A E G; Pittard, J M; Van Loo, S


    In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance of the thermal instablity for the formation of clouds in the interstellar medium. Even in the past several years, many papers have concerned the role of the thermal instability in the production of molecular clouds. About three and a half decades ago, astrophysicists investigating radiative shocks noticed that for many cooling laws such shocks are unstable. Attempts to address the effects of cosmic rays on the stablity of radiative media that are initially uniform or that have just passed through shocks have been made. The simplest approach to such studies involves the assumption that the cosmic rays behave as a fluid. Work based on such an approach is described. Cosmic rays have no effect on the stability of initially uniform, static media with respect to isobaric perturb...

  14. Visco-Resistive Plasmoid Instability

    CERN Document Server

    Comisso, Luca


    The plasmoid instability in visco-resistive current sheets is analyzed in both the linear and nonlinear regimes. The linear growth rate and the wavenumber are found to scale as $S^{1/4} {\\left( {1 + {P_m}} \\right)}^{-5/8}$ and $S^{3/8} {\\left( {1 + {P_m}} \\right)}^{-3/16}$ with respect to the Lundquist number $S$ and the magnetic Prandtl number $P_m$. Furthermore, the linear layer width is shown to scale as $S^{-1/8} {(1+P_m)}^{1/16}$. The growth of the plasmoids slows down from an exponential growth to an algebraic growth when they enter into the nonlinear regime. In particular, the time-scale of the nonlinear growth of the plasmoids is found to be $\\tau_{NL} \\sim S^{-3/16} {(1 + P_m)^{19/32}}{\\tau _{A,L}}$. The nonlinear growth of the plasmoids is radically different from the linear one and it is shown to be essential to understand the global current sheet disruption. It is also discussed how the plasmoid instability enables fast magnetic reconnection in visco-resistive plasmas. In particular, it is shown t...

  15. 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


    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.

  16. The Chemistry of Beer Instability (United States)

    Stewart, Graham G.


    Compared to most other alcoholic beverages, beer is unique because it is unstable when in the final package. This instability can be divided into biological and nonbiological instability. Nonbiological stability of beer involves a wide range of chemical processes and can be considered in a number of categories: physical, flavor, light, foam, and gushing. It is the balance between flavanoid polyphenols (tannoids) and sensitive proteins that specifically combine with polyphenols to form haze that largely dictates physical stability. The flavor stability of beer primarily depends on the oxygen concentration of packaged beer but is influenced by all stages of the brewing process. Foam stability in a glass of beer reflects the quality of the beverage. The backbone of foam is hydrophobic polypeptides. Novel brewing processes such as high-gravity brewing result in a disproportionate loss of these polypeptides and have a negative effect on the foam stability of the resulting beer. Beer is light sensitive, especially in the 350 500 nm range. Beer exposed to this wavelength range in clear or green glass containers quickly develop nauseous skunky-like off-flavors resulting from the formation of 3-methyl-2-butene-1-thiol. Methods of enhancing all of these types of beer stability are discussed.

  17. Dosimetry of charged and neutral particles onboard a stratospheric balloon (United States)

    Dönsdorf, Esther Miriam; Burmeister, Soenke; Heber, Bernd; Benton, Eric; Berger, Thomas

    The interaction of the primary galactic cosmic rays with constituents of the atmosphere leads to a complex secondary radiation field at high altitudes. Of special interest for aviation and thereby also for radiation protection is the height up to 30 km where the radiation field consists of charged and neutral particles. For the determination of the dose rates up to this altitude in the Earth's atmosphere a stratopheric balloon flight will be performed in central Oklahoma which has a cutoff rigidity of about 4 GV. Onboard there will be two different active radiation detector systems to measure the dose of charged and neutral particles in the stratosphere. The first one is a silicon telescope which consists of two 2 cm2 silicon PIN-photodiodes used as semiconductor detectors. This instrument will mainly be used to measure the charged component of the radiation field due to the fact that the silicon detectors have a rather low efficiency for the detection of neutrons and gammas with energies higher than 60 keV. The second instrument is a so called phoswich detector. It is composed of two dissimilar scintillators optically coupled to each other and to a common photomultiplier tube. For this experimental setup a combination of a fast plastic scintillator BC412 and a slow inorganic scintillator CsI(Na) is used. The pulses from the two scintillators will be separated by applying pulse shape analysis. These two different scintillator materials have been chosen because BC412 is hydrogen rich and thus the cross section for fast neutrons is relatively high and CsI(Na) has a high cross section for gamma radiation. The objective of the phoswich detector is to distinguish between gammas and neutrons but it is also possible to measure charged particles with this setup. The aim of the balloon flight is to determine the dose measured with these two different instruments and in particular to differentiate between the dose induced by charged particles and by the different neutral

  18. 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


    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...

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Understanding cosmic rays with Balloon and Space Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Picozza, P., E-mail: [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)


    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.

  1. Particle and thermal transport due to drift resistive ballooning modes (United States)

    Goldstein, T.; Rafiq, T.; Kritz, A. H.; Bateman, G.; Pankin, A. Y.


    The ion-temperature-gradient and trapped electron modes are primary candidates for producing the turbulence that drives anomalous transport in the core of magnetically confined plasmas. The situation at the edge is different. Since the edge plasma is influenced strongly by collisions, it is expected that resistive ballooning modes (RBMs) are an important driver of turbulence in the edge region. In this work, a new advanced RBM model [1] is tested as a function of plasma parameters. In this model, the eigenvalues and eigenvectors are used together with a quasi-linear mixing length estimate to determine fluxes and diffusivities. Particle and thermal transport coefficients are investigated in systematic scans over plasma density, density gradient, electron and ion temperature gradients, magnetic q, collisions, magnetic shear, finite Larmor radius effects, and pressure gradient. In the low temperature plasma region, it is found that RBM diffusivities increase with increasing density gradient, magnetic q, and collisionality.[4pt] [1] T. Rafiq, et al, poster at this APS meeting

  2. Right ventricular function before and after percutaneous balloon mitral valvuloplasty. (United States)

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


    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.

  3. 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


    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...

  4. CdZnTe Background Measurement at Balloon Altitudes

    CERN Document Server

    Bloser, P F; Narita, T; Harrison, F


    We report results of an experiment conducted in May 1997 to measure CdZnTe background and background reduction schemes in space flight conditions similar to those of proposed hard X-ray astrophysics missions. A 1 cm^2 CdZnTe detector was placed adjacent to a thick BGO anticoincidence shield and flown piggybacked onto the EXITE2 scientific balloon payload. The planar shield was designed to veto background countsproduced by local gamma-ray production in passive material and neutron interactions in the detector. The CdZnTe and BGO were partially surrounded by a Pb-Sn-Cu shield to approximate the grammage of an X-ray collimator, although the field of view was still ~2 pi sr. At an altitude of 127000 feet we find a reduction in background by a factor of 6 at 100 keV. The non-vetoed background is 9 X 10^{-4} cts /cm^2-sec-keV at 100 keV, about a factor of 2 higher than that of the collimated (4.5 deg FWHM) EXITE2 phoswich detector. We compare our recorded spectrum with that expected from simulations using GEANT and...

  5. 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


    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 ...

  6. Interfacial instabilities in vibrated fluids (United States)

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


    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

  7. On the descriptions of beam instabilities

    CERN Document Server

    Maillard, Antoine


    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.

  8. The short circuit instability in protoplanetary disks

    DEFF Research Database (Denmark)

    Hubbard, A.; McNally, C.P.; Mac Low, M.M.;


    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...

  9. 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,


    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

  10. Cultural diversity, economic development and societal instability (United States)

    Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.


    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.

  11. Mapping Instabilities in Polymer Friction (United States)

    Rand, Charles; Crosby, Alfred


    Schallamach waves are instabilities that occur as interfaces between a soft elastomer and rigid surface slide past each other.(1) The presence of Schallamach waves can lead to drastic changes in frictional properties. Although the occurrence of Schallamach waves has been studied for the past several decades, a general map relating fundamental material properties, geometry, and operating conditions (i.e. speed and temperature) has not been established. Using a combinatorial approach, we illustrate the role of modulus, testing velocity and surface energetics of crosslinked poly(dimethyl siloxane) on the generation Schallamach waves. This knowledge will be used with polymer patterning processes to fabricate responsive coatings for applications such as anti-fouling coatings. (1)Schallamach, A.;Wear 1971,17, 301-312.

  12. Transient spirals as superposed instabilities

    CERN Document Server

    Sellwood, J A


    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...

  13. Gravitational Instability of a Kink

    CERN Document Server

    Barreto, W; Lehner, L; Winicour, J


    We study the equilibria of a self-gravitating scalar field in the region outside a reflecting barrier. By introducing a potential difference between the barrier and infinity, we create a kink which cannot decay to a zero energy state. In the realm of small amplitude, the kink decays to a known static solution of the Einstein-Klein-Gordon equation. However, for larger kinks the static equilibria are degenerate, forming a system with two energy levels. The upper level is unstable and, under small perturbations, decays to the lower energy stable equilibrium. Under large perturbations, the unstable upper level undergoes collapse to a black hole. The equilibrium of the system provides a remarkably simple and beautiful illustration of a turning point instability.

  14. Chromosomal instability determines taxane response

    DEFF Research Database (Denmark)

    Swanton, C.; Nicke, B.; Schuett, M.;


    -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....

  15. Hydrodynamic Instabilities in Rotating Fluids

    Institute of Scientific and Technical Information of China (English)



    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.

  16. Instabilities, turbulence and transport in a magnetized plasma; Instabilites, turbulence et transport dans un plasma magnetise

    Energy Technology Data Exchange (ETDEWEB)

    Garbet, X


    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.)

  17. Secondary instability in boundary-layer flows (United States)

    Nayfeh, A. H.; Bozatli, A. N.


    The stability of a secondary Tollmien-Schlichting wave, whose wavenumber and frequency are nearly one half those of a fundamental Tollmien-Schlichting instability wave is analyzed using the method of multiple scales. Under these conditions, the fundamental wave acts as a parametric exciter for the secondary wave. The results show that the amplitude of the fundamental wave must exceed a critical value to trigger this parametric instability. This value is proportional to a detuning parameter which is the real part of k - 2K, where k and K are the wavenumbers of the fundamental and its subharmonic, respectively. For Blasius flow, the critical amplitude is approximately 29% of the mean flow, and hence many other secondary instabilities take place before this parametric instability becomes significant. For other flows where the detuning parameter is small, such as free-shear layer flows, the critical amplitude can be small, thus the parametric instability might play a greater role.

  18. Tensile Instability in a Thick Elastic Body (United States)

    Overvelde, Johannes T. B.; Dykstra, David M. J.; de Rooij, Rijk; Weaver, James; Bertoldi, Katia


    A range of instabilities can occur in soft bodies that undergo large deformation. While most of them arise under compressive forces, it has previously been shown analytically that a tensile instability can occur in an elastic block subjected to equitriaxial tension. Guided by this result, we conducted centimeter-scale experiments on thick elastomeric samples under generalized plane strain conditions and observed for the first time this elastic tensile instability. We found that equibiaxial stretching leads to the formation of a wavy pattern, as regions of the sample alternatively flatten and extend in the out-of-plane direction. Our work uncovers a new type of instability that can be triggered in elastic bodies, enlarging the design space for smart structures that harness instabilities to enhance their functionality.

  19. Taylor instability in rhyolite lava flows (United States)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.


    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.

  20. 3-D nonlinear evolution of MHD instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, G.; Hicks, H. R.; Wooten, J. W.


    The nonlinear evolution of ideal MHD internal instabilities is investigated in straight cylindrical geometry by means of a 3-D initial-value computer code. These instabilities are characterized by pairs of velocity vortex cells rolling off each other and helically twisted down the plasma column. The cells persist until the poloidal velocity saturates at a few tenths of the Alfven velocity. The nonlinear phase is characterized by convection around these essentially fixed vortex cells. For example, the initially centrally peaked temperature profile is convected out and around to form an annulus of high temperature surrounding a small region of lower temperature. Weak, centrally localized instabilities do not alter the edge of the plasma. Strong, large-scale instabilities, resulting from a stronger longitudinal equilibrium current, drive the plasma against the wall. After three examples of instability are analyzed in detail, the numerical methods and their verification are discussed.

  1. Whipping Instabilities in Electrified Liquid Jets

    CERN Document Server

    Marin, Alvaro G; Loscertales, Ignacio G; Barrero, Antonio


    A liquid jet may develop different types of instabilities, like the so-called Rayleigh-Plateau instability, which breaks the jet into droplets. However, another type of instabilities may appear when we electrify a liquid jet and induce some charge at his surface. Among them, the most common is the so-called Whipping Instability, which is characterized by violent and fast lashes of the jet. In the submitted fluid dynamic video(see, we will show an unstable charged glycerine jet in a dielectric liquid bath, which permits an enhanced visualization of the instability. For this reason, it is probably the first time that these phenomena are visualized with enough clarity to analyze features as the effect of the feeding liquid flow rate through the jet or as the surprising spontaneous stabilization at some critical distance to the ground electrode.

  2. Application of new balloon catheters in the treatment of congenital heart defects (United States)

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


    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. 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.

  4. Double balloon enteroscopy in the old: Experience from China

    Institute of Scientific and Technical Information of China (English)

    Qiong He; Bing Xiao; Ya-Li Zhang; Bo Jiang; Yang Bai; Fa-Chao Zhi; Qiang Zhang; Jian-Dong Li; Ya-Dong Wang; Tian-Mo Wan; Zhen-Yu Chen; De-Shou Pan; Jian-Qun Cai; Si-De Liu


    AIM:To evaluate the safety,efficacy and management of double balloon enteroscopy (DBE) carried out in those aged individuals with suspicious small intestine diseases.METHODS:DBE is a wonderful invention of the past decade and is widely used as an examination tool for the gastrointestinal tract.From January 2003 to July 2011,data from patients who were ≥ 65 years old and underwent DBE examination in the Nanfang Hospital were included in a retrospective analysis.RESULTS:Fifty-nine individuals were found and subsequently analyzed.The mean age was 69.63 ± 3.89 years (range 65-84),34 were males.Indications for DBE were melena/hematochezia (36 cases),abdominal pain (15 cases),diarrhea (3 cases),stool change (1 case),weight loss (1 case),vomiting (2 cases),and de bilitation (1 case).The average duration of symptoms was 33.34 ± 64.24 mo.Twenty-seven patients suffered from age-related diseases.Severe complications were not found during and after DBE.Comparison between systolic and diastolic blood pressure before and after DBE was statistically significant (mean ± SD,P < 0.01,P < 0.05,respectively).Small bowel pathologies were found by DBE in 35 patients,definite diagnoses were made in 31 cases,and detection rate and diagnostic yield for DBE were 68.6% and 60.8%,respectively.CONCLUSION:DBE is a safe and effective method for gastrointestinal examination in the aged population.Aging alone is not a risk factor for elderly patients with suspicious gastrointestinal diseases and thorough preparation prior to the DBE procedure should be made for individuals with multiple diseases especially cardiopulmonary disorders.

  5. Material Properties Analysis of Structural Members in Pumpkin Balloons (United States)

    Sterling, W. J.


    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

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

    Directory of Open Access Journals (Sweden)

    A. Gallice


    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

  7. Formation and evolution of flapping and ballooning waves in magnetospheric plasma sheet (United States)

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


    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.

  8. 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)


    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.

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

    Marshall, T. C.; Stolzenburg, M.


    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


    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. 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.


    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.).

  12. Status of the Balloon-Borne X-ray Polarimetry Mission X-Calibur (United States)

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


    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.

  13. 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)


    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.)

  14. Balloon catheter dilation technology combined with a fibrolaryngoscope to treat a maxillary sinus cyst. (United States)

    Xiao, Jianxin; Chen, Junming; Wang, Yuejian


    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.

  15. Femorofemoral grafts for lower limb ischemia caused by intra-aortic balloon pump. (United States)

    Friedell, M L; Alpert, J; Parsonnet, V; Brief, D K; Brener, B J; Goldenkranz, R J; Nozick, J


    From January 1975 to December 1985, 1454 patients had an intra-aortic balloon inserted for cardiac assistance. Eighty balloon-dependent patients had severe limb ischemia and required a femorofemoral graft (FFG) (5% of the total group of patients). Twenty-nine of the 80 patients with grafts (or 36%) left the hospital and 28 were followed up for an average of 40 months to determine late complications associated with the crossover grafts. All grafts remained patent. The 28 patients were classified into five groups according to the degree and type of lower limb ischemia. Group I consisted of 13 asymptomatic patients (46%); group II had four (14%) patients with mild claudication caused by preexisting peripheral arteriosclerosis; group III comprised four patients (14%) without preexisting disease but claudication subsequent to the FFG; group IV had five patients with irreversible ischemic sequelae before grafting ending in amputation, foot drop, or persistent paresthesia; and group V consisted of two patients with graft infection (7%). The perioperative mortality rate of the balloon-dependent patients with an FFG (64%) reflects the gravity of the cardiac condition. Placement of an FFG to relieve limb ischemia in these patients is followed by few immediate or late complications in the survivors and any persistent limb changes were related to the prolonged ischemia present before revascularization. Our data suggest that in balloon-dependent patients with limb-threatening ischemia, aggressive use of the FFG is limb-saving, durable, and allows continuation of balloon support.

  16. Quantum effects in beam-plasma instabilities

    CERN Document Server

    Bret, A


    Among the numerous works on quantum effects that have been published in recent years, streaming instabilities in plasma have also been revisited. Both the fluid quantum and the kinetic Wigner-Maxwell models have been used to explore quantum effects on the Weibel, Filamentation and Two-Stream instabilities. While quantum effects usually tend to reduce the instabilities, they can also spur new unstable branches. A number of theoretical results will be reviewed together with the implications to one physical setting, namely the electron driven fast ignition scenario.

  17. Fingering instability in combustion: an extended view. (United States)

    Zik, O; Moses, E


    We detail the experimental situation concerning the fingering instability that occurs when a solid fuel is forced to burn against a horizontal oxidizing wind. The instability appears when the Rayleigh number for convection is below criticality. The focus is on the developed fingering state. We present direct measurements of the depletion of oxygen by the front as well as new results that connect heat losses to the characteristic scale of the instability. In addition, we detail the experimental system, elaborate (qualitatively and quantitatively) on the results that were previously presented, and discuss new observations. We also show that the same phenomenological model applies to electrochemical deposition.

  18. More on core instabilities of magnetic monopoles

    CERN Document Server

    Striet, J


    In this paper we present new results on the core instability of the 't Hooft Polyakov monopoles we reported on before. This instability, where the spherical core decays in a toroidal one, typically occurs in models in which charge conjugation is gauged. In this paper we also discuss a third conceivable configuration denoted as ``split core'', which brings us to some details of the numerical methods we employed. We argue that a core instability of 't Hooft Polyakov type monopoles is quite a generic feature of models with charged Higgs particles.

  19. Careers in conditions of instability

    Directory of Open Access Journals (Sweden)

    Hohlova Valentina Vasil'evna


    Full Text Available The purpose of this work is the research of the social-economic phenomenon of a career as a result of conscious human position and behaviour in the field of employment, which is connected with job and professional growth, as a chain of events which are components of life, the sequence of professional activities and other biographical roles, which all together express the commitment of a person’s activity according to his generalized model of self-development. On the basis of the theoretical analysis the dependence of making a career in the condition of instability and indefiniteness on job market flexibility, erosion and even the destruction of the usual way of life and labor relations. The career concepts under the conditions of flexible capitalism and of career policy as the typology of empiric differences of job biographic models are considered. The peculiarity of the proposed career policy concept is that its individual alternatives of career making oppose to organization management and personal demands: the difference between a professional’s wishes and a specific strategy of the development phases are quite noticeable. According to the results of empiric research carried out through the methods of interview, polling, expert assessment, the analysis of the received results, the mathematical data processing the basic types of the career policy and its connection with the organization’s personal development are revealed.

  20. Boyle's law and gravitational instability

    CERN Document Server

    Lombardi, M; Lombardi, Marco; Bertin, Giuseppe


    We have re-examined the classical problem of the macroscopic equation of state for a hydrostatic isothermal self-gravitating gas cloud bounded by an external medium at constant pressure. We have obtained analytical conditions for its equilibrium and stability without imposing any specific shape and symmetry to the cloud density distribution. The equilibrium condition can be stated in the form of an upper limit to the cloud mass; this is found to be inversely proportional to the power 3/2 of a form factor \\mu characterizing the shape of the cloud. In this respect, the spherical solution, associated with the maximum value of the form factor, \\mu = 1, turns out to correspond to the shape that is most difficult to realize. Surprisingly, the condition that defines the onset of the Bonnor instability (or gravothermal catastrophe) can be cast in the form of an upper limit to the density contrast within the cloud that is independent of the cloud shape. We have then carried out a similar analysis in the two-dimensiona...

  1. Magnetorotational instability in protoplanetary discs

    CERN Document Server

    Salmeron, Roberto Aureliano; Salmeron, Raquel; Wardle, Mark


    We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionised, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards the midplane, so charges are carried by electrons and ions only. Solutions are obtained at representative radial locations from the central protostar for different choices of the initial magnetic field strength, sources of ionisation, and disc surface density. The MRI is active over a wide range of magnetic field strengths and fluid conditions in low conductivity discs. For the minimum-mass solar nebula model, incorporating cosmic ray ionisation, perturbations grow at 1 AU for B < 8 G. For a significant subset of these strengths (0.2 - 5 G), the growth rate is of order the ideal MHD rate (0.75 Omega). Similarly, when cosmic rays are assumed to be excluded from the disc by the winds emitted by the magnetically active protostar, unstable modes grow at this radius for B less...

  2. The azimuthal magnetorotational instability (AMRI)

    CERN Document Server

    Ruediger, G; Schultz, M; Hollerbach, R; Stefani, F


    We consider the interaction of differential rotation and toroidal fields that are current-free in the gap between two corotating axially unbounded cylinders. It is shown that nonaxisymmetric perturbations are unstable if the rotation rate and Alfven frequency of the field are of the same order almost independent of the magnetic Prandtl number Pm. For the very steep rotation law \\Omega\\propto R^{-2} (the Rayleigh limit) this Azimuthal MagnetoRotational Instability (AMRI) scales with the ordinary Reynolds number and the Hartmann number, which allows a laboratory experiment with liquid metals like sodium or gallium in a Taylor-Couette container. The growth rate of AMRI scales with \\Omega^2 in the low-conductivity limit and with \\Omega in the high-conductivity limit. For the weakly nonlinear system the numerical values of the kinetic energy and the magnetic energy are derived for magnetic Prandtl numbers between 0.05 and unity. We find that the magnetic energy scales with the magnetic Reynolds number Rm, while th...

  3. Thermal instability of cell nuclei (United States)

    Warmt, Enrico; Kießling, Tobias R.; Stange, Roland; Fritsch, Anatol W.; Zink, Mareike; Käs, Josef A.


    DNA is known to be a mechanically and thermally stable structure. In its double stranded form it is densely packed within the cell nucleus and is thermo-resistant up to 70\\:^\\circ {\\rm{C}}. In contrast, we found a sudden loss of cell nuclei integrity at relatively moderate temperatures ranging from 45 to 55\\:^\\circ {\\rm{C}}. In our study, suspended cells held in an optical double beam trap were heated under controlled conditions while monitoring the nuclear shape. At specific critical temperatures, an irreversible sudden shape transition of the nuclei was observed. These temperature induced transitions differ in abundance and intensity for various normal and cancerous epithelial breast cells, which clearly characterizes different cell types. Our results show that temperatures slightly higher than physiological conditions are able to induce instabilities of nuclear structures, eventually leading to cell death. This is a surprising finding since recent thermorheological cell studies have shown that cells have a lower viscosity and are thus more deformable upon temperature increase. Since the nucleus is tightly coupled to the outer cell shape via the cytoskeleton, the force propagation of nuclear reshaping to the cell membrane was investigated in combination with the application of cytoskeletal drugs.

  4. Transient spirals as superposed instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Sellwood, J. A. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Carlberg, R. G., E-mail:, E-mail: [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)


    We present evidence that recurrent spiral activity, long manifested in simulations of disk galaxies, results from the superposition of a few transient spiral modes. Each mode lasts between 5 and 10 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 low-mass disks.

  5. Pulsational-Pair Instability Supernovae

    CERN Document Server

    Woosley, S E


    The final evolution of stars in the mass range 60 - 150 solar masses is explored. Depending upon their mass loss and rotation rates, many of these stars will end their lives as pulsational pair-instability supernovae. Even a non-rotating 70 solar mass star is pulsationally unstable during oxygen shell burning and can power a sub-luminous supernova. Rotation decreases the limit further. For more massive stars, the pulsations are less frequent, span a longer time, and are more powerful. Violent pulsations eject not only any residual low density envelope, but also that fraction of the helium core mass outside about 35 - 50 solar masses. The remaining core of helium and heavy elements continues to evolve, ultimately forming an iron core of about 2.5 solar masses that probably collapses to a black hole. A variety of observational transients result with total durations ranging from days to 10,000 years, and luminosities from 10$^{41}$ to 10$^{44}$ erg s$^{-1}$. Many transients resemble ordinary Type IIp supernovae,...

  6. Taylor Instability of Incompressible Liquids (United States)

    Fermi, E.; von Neumann, J.


    A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

  7. Thermal design and performance of the balloon-borne large aperture submillimeter telescope for polarimetry BLASTPol

    CERN Document Server

    Soler, J D; Angilè, F E; Benton, S J; Devlin, M J; Dober, B; Fissel, L M; Fukui, Y; Galitzki, N; Gandilo, N N; Klein, J; Korotkov, A L; Matthews, T G; Moncelsi, L; Mroczkowski, A; Netterfield, C B; Novak, G; Nutter, D; Pascale, E; Poidevin, F; Savini, G; Scott, D; Shariff, J A; Thomas, N E; Truch, M D; Tucker, C E; Tucker, G S; Ward-Thompson, D


    We present the thermal model of the Balloon-borne Large-Aperture Submillimeter Telescope for Polarimetry (BLASTPol). This instrument was successfully flown in two circumpolar flights from McMurdo, Antarctica in 2010 and 2012. During these two flights, BLASTPol obtained unprecedented information about the magnetic field in molecular clouds through the measurement of the polarized thermal emission of interstellar dust grains. The thermal design of the experiment addresses the stability and control of the payload necessary for this kind of measurement. We describe the thermal modeling of the payload including the sun-shielding strategy. We present the in-flight thermal performance of the instrument and compare the predictions of the model with the temperatures registered during the flight. We describe the difficulties of modeling the thermal behavior of the balloon-borne platform and establish landmarks that can be used in the design of future balloon-borne instruments.

  8. Loss of Guide Wire: A Rare Complication of Intra-Aortic Balloon Pump Insertion

    Directory of Open Access Journals (Sweden)

    Manouchehr Hekmat


    Full Text Available At the final stages of a coronary artery bypass graft operation on a 64-year-old man, an experienced physician attempted to insert an intra-aortic balloon pump into the femoral artery via the Seldinger technique. However, while the balloon pump was being passed over the guide wire, the latter was completely lost.The guide wire should be held at the tip at all times to prevent passage into the vessel. Strict adherence to this rule will prevent guide-wire loss, which is, albeit rare and completely avoidable, a potentially life-threatening complication of central vein or artery catheterization, with reported fatality rates of up to 20% when the whole wire is lost. The literature contains several reports on guide-wire loss during central venous, arterial, and hemodialysis catheterization, but we report for the first time the loss of a guide wire as a rare complication of intra-aortic balloon pump insertion.

  9. Design and construction of a carbon fiber gondola for the SPIDER balloon-borne telescope

    CERN Document Server

    Soler, J D; Amiri, M; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, C; Contaldi, C C; Crill, B P; Doré, O P; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Gambrel, A E; Gandilo, N N; 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; Kuo, C L; MacTavish, C J; Mason, P V; Megerian, K G; Moncelsi, L; Nagy, J M; Netterfield, C B; O'Brient, R; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Shariff, J A; Trangsrud, A; Tucker, C; Tucker, R S; Turner, A D; Weber, A C; Wiebe, D V; Young, E Y


    We introduce the light-weight carbon fiber and aluminum gondola designed for the SPIDER balloon-borne telescope. SPIDER is designed to measure the polarization of the Cosmic Microwave Background radiation with unprecedented sensitivity and control of systematics in search of the imprint of inflation: a period of exponential expansion in the early Universe. The requirements of this balloon-borne instrument put tight constrains on the mass budget of the payload. The SPIDER gondola is designed to house the experiment and guarantee its operational and structural integrity during its balloon-borne flight, while using less than 10% of the total mass of the payload. We present a construction method for the gondola based on carbon fiber reinforced polymer tubes with aluminum inserts and aluminum multi-tube joints. We describe the validation of the model through Finite Element Analysis and mechanical tests.

  10. Balloon observations of Galactic cosmic ray helium before and during a Forbush decrease (United States)

    Clem, J. M.; Guzik, T. G.; Lijowski, M.; Wefel, J. P.; Beatty, J. J.; Ficenec, D. J.; Tobias, S.; Mitchell, J. W.; Mckee, S.; Nutter, S.


    The energy spectrum of Galactic cosmic ray helium was measured in two different balloon experiments launched four days apart from Canada: SMILI-I on Sept 1, 1989 and MASS on Sept 5, 1989. A slow Forbush decrease began on Sept 4, 1989 and had not reached its maximum at the time of the MASS flight. Comparison of the balloon measurements shows a fractional decrease of 0.37 to 0.15 in the Helium flux between 200 and 450 MeV/nucleon (1.2-2.0 GV). The rigidity dependence is analyzed in two models and found to be steeper than previous observations. Interplanetary particle data and ground-based Neutron Monitor results are consistent with the balloon observations. Probable sources for this Forbush decrease are discussed.

  11. Multi-Modal Image Registration and Matching for Localization of a Balloon on Titan (United States)

    Ansar, Adnan I.


    A solution was developed that matches visible/IR imagery aboard a balloon in Saturn's moon Titan's atmosphere to SAR (synthetic aperture radar) and visible/IR data acquired from orbit. A balloon in Titan's atmosphere must be able to localize itself autonomously both globally and with respect to local terrain. The orbital data is used to provide the balloon imagery with global context. The work is novel in applying mutual information (MI) to orbital vs. aerial data. There are unique challenges in this setting. Image offsets are much higher than in medical imaging, there is local distortion due to 3D terrain relief, and the fields of regard from orbit and from the air are quite different.

  12. A balloon-borne millimeter-wave telescope for cosmic microwave background anisotropy measurements

    CERN Document Server

    Fixsen, D J; Cottingham, D A; Folz, W C; Inman, C A; Kowitt, M S; Meyer, S; Page, L A; Puchalla, J L; Ruhl, J E; Silverberg, R F


    We report on the characteristics and design details of the Medium Scale Anisotropy Measurement (MSAM), a millimeter-wave, balloon-borne telescope that has been used to observe anisotropy in the Cosmic Microwave Background Radiation (CMBR) on 0\\fdg5 angular scales. The gondola is capable of determining and maintaining absolute orientation to a few arcminutes during a one-night flight. Emphasis is placed on the optical and pointing performance as well as the weight and power budgets. We also discuss the total balloon/gondola mechanical system. The pendulation from this system is a ubiquitous perturbation on the pointing system. A detailed understanding in these areas is needed for developing the next generation of balloon-borne instruments.

  13. Fibular free flap with arteria peronea magna: the role of preoperative balloon occlusion. (United States)

    Rahmel, Benjamin B; Snow, Thomas M; Batstone, Martin D


    The free fibular osteocutaneous flap is a commonly used donor for reconstruction of mandibular defects. Vascular abnormalities and leg trauma are relative contraindications to the use of a fibular free flap. Peroneal arteria magna (PAM) is one such vascular abnormality that may preclude the use of the graft due to the high risk of lower-limb ischemia. Lower-limb angiography is the standard for assessing the lower-limb vascular anatomy; however, the indications remain controversial. Although balloon occlusion has been used to assess the vascular supply in distal bypass surgery, there have no reported cases of balloon occlusion to assess the viability of the distal extremity with PAM. Intraoperative assessment of vascular anatomy with an aborted harvest can lead to significant morbidity and cost. Balloon occlusion provides a relatively safe and minimally invasive technique for assessment of potential lower-limb ischemia in patients with PAM.

  14. Preliminary Electric Field Results From A Multiple Balloon Campaign to Study Relativistic Electron Loss (United States)

    Bering, E. A.; Kokorowski, M.; Holzworth, R. H.; Sample, J. G.; McCarthy, M. P.; Smith, D. M.; Parks, G. K.; Millan, R. M.; Woodger, L.; Reddell, B. D.; Lay, E.; Bale, S. D.; Pulupa, M.; O'Brien, T. P.; Blake, J. B.; Lin, R. P.; Moraal, H.; Stoker, P.; Hughes, A. R.; Collier, A. B.


    The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. Quantifying and understanding losses is an integral part of understanding the variability of relativistic electrons in the radiation belts. Balloon-based experiments directly measure precipitation and thus provide a method for quantifying losses, while the nearly stationary platform allows for the separation of temporal and spatial variations. A new class of precipitation event, characterized by extremely hard spectra, short durations, and complex temporal structure, occurring in the evening to midnight sector, was discovered by the INTERBOA balloon in 1996 and studied further by the MAXIS balloon in 2000. The MINIS campaign provided the first opportunities for multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and at near-conjugate locations. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba at 0850 UT on 21 January 2005 and 0140 UT on 25 January 2005. Four balloons, each carrying an X-ray spectrometer, a Z-axis search coil magnetometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). The Southern launches took place at 1400 UT on 17 January, 1309 UT on 19 January, 2115 UT on 20 January, and 0950 UT on 24 January 2005. In this paper, we present the preliminary results from the MINIS South electric field instrumentation. We have good DC and VLF electric field data from all payloads, and the payload rotation mechanism worked in all four as well. The campaign began with two large solar flares. In the post-flare environment, some very magnetospherically active periods are included in our data, with strong and

  15. Preliminary X-ray Results From A Multiple Balloon Campaign to Study Relativistic Electron Loss (United States)

    Sample, J. G.; Kokorowski, M.; Millan, R. M.; McCarthy, M.; Holzworth, R. H.; Bering, E. A.; Parks, G. K.; Woodger, L.; Reddell, B. D.; Lay, E.; Pulupa, M.; Bale, S.; O'Brien, T. P.; Blake, J. B.; Lin, R. P.; Moraal, H.; Stoker, P.; Hughes, A. R.; Collier Cameron, A.; Smith, D. M.


    The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. Quantifying and understanding losses is an integral part of understanding the variability of relativistic electrons in the radiation belts. Balloon-based experiments directly measure precipitation and thus provide a method for quantifying losses, while the nearly stationary platform allows for the separation of temporal and spatial variations. A new class of precipitation event, characterized by extremely hard spectra, short durations, and complex temporal structure, occurring in the evening to midnight sector, was discovered by the INTERBOA balloon in 1996 and studied further by the MAXIS balloon in 2000. The MINIS campaign provided the first opportunities for multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and at near-conjugate locations. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba at 0850 UT on 21 January 2005 and 0140 UT on 25 January 2005. Four balloons, each carrying an X-ray spectrometer, a Z-axis search coil magnetometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). The Southern launches took place at 1400 UT on 17 January, 1309 UT on 19 January, 2115 UT on 20 January, and 0950 UT on 24 January 24 2005. In this paper, we present the preliminary results from the MINIS North and South X-ray data. The first and second Southern payloads observed a rarely-seen phenomenon: gamma-ray line emission from nuclear interactions of solar protons in the Earth's atmosphere. When the solar particles abated, there were numerous opportunities for simultaneous observations of MeV precipitation from multiple

  16. Balloon Coating with Rapamycin Using an On-site Coating Device

    Energy Technology Data Exchange (ETDEWEB)

    Schmehl, Joerg, E-mail: [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Ruhr, Juergen von der [Institute of Anatomy, University of Tuebingen (Germany); Dobratz, Markus; Kehlbach, Rainer [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Braun, Isabelle [Translumina GmbH (Germany); Greiner, Tim-Oliver [Clinic of Thoracic and Cardiovascular Surgery, University Hospital of Tuebingen (Germany); Claussen, Claus D. [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen (Germany); Behnisch, Boris [Translumina GmbH (Germany)


    Purpose. The efficacy of drug-eluting balloons has been demonstrated in clinical trials. The drug predominantly used is paclitaxel because of its lipophilic properties and the rapid onset of action. The aim of the investigation was to evaluate the feasibility and efficacy of an alternative balloon coating with rapamycin that can be applied on site.MethodsThe balloon coating (3.0/18 and 3.0/12 mm, Cathy No. 4, Translumina GmbH) with rapamycin was conducted with a coating machine (Translumina GmbH). Concentrations were 2, 2 Multiplication-Sign 2, 3, and 4 %. Measurements regarding the amount of substance released to the vessel wall were carried out on explanted porcine coronaries by means of ultraviolet and visible-light spectroscopy. Inflation time varied between 30 and 120 s. The biological effect of the coating was evaluated in a porcine peripheral overstretch and stent implantation model. Results. The amount of rapamycin on the balloon surface ranged from 558 {+-} 108 {mu}g for the 2 % solution to 1,441 {+-} 228 {mu}g in the 4 % solution. An amount of 95 {+-} 63-193 {+-} 113 {mu}g was released into the vessel wall. The quantitative measurements of the angiographic examinations 4 weeks after treatment revealed a reduction of diameter stenosis from 20.6 {+-} 17.4 % in the control group to 11.6 {+-} 5.5 % in the drug-eluting balloon group. Conclusion. A balloon coating with rapamycin omitting an excipient is possible with a dose-adjustable coating machine. However, the biological effects are moderate, which make further optimization of the coating process and evaluation of appropriate excipients necessary.

  17. Lifting options for stratospheric aerosol geoengineering: advantages of tethered balloon systems. (United States)

    Davidson, Peter; Burgoyne, Chris; Hunt, Hugh; Causier, Matt


    The Royal Society report 'Geoengineering the Climate' identified solar radiation management using albedo-enhancing aerosols injected into the stratosphere as the most affordable and effective option for geoengineering, but did not consider in any detail the options for delivery. This paper provides outline engineering analyses of the options, both for batch-delivery processes, following up on previous work for artillery shells, missiles, aircraft and free-flying balloons, as well as a more lengthy analysis of continuous-delivery systems that require a pipe connected to the ground and supported at a height of 20 km, either by a tower or by a tethered balloon. Towers are shown not to be practical, but a tethered balloon delivery system, with high-pressure pumping, appears to have much lower operating and capital costs than all other delivery options. Instead of transporting sulphuric acid mist precursors, such a system could also be used to transport slurries of high refractive index particles such as coated titanium dioxide. The use of such particles would allow useful experiments on opacity, coagulation and atmospheric chemistry at modest rates so as not to perturb regional or global climatic conditions, thus reducing scale-up risks. Criteria for particle choice are discussed, including the need to minimize or prevent ozone destruction. The paper estimates the time scales and relatively modest costs required if a tethered balloon system were to be introduced in a measured way with testing and development work proceeding over three decades, rather than in an emergency. The manufacture of a tether capable of sustaining the high tensions and internal pressures needed, as well as strong winds, is a significant challenge, as is the development of the necessary pumping and dispersion technologies. The greatest challenge may be the manufacture and launch of very large balloons, but means have been identified to significantly reduce the size of such balloons or aerostats.

  18. Healing after arterial dilatation with radiofrequency thermal and nonthermal balloon angioplasty systems. (United States)

    Kaplan, J; Barry, K J; Connolly, R J; Nardella, P C; Hayes, L L; Lee, B I; Waller, B F; Becker, G J; Callow, A D


    Thermal balloon angioplasty has been proposed as a means of reducing acute and delayed reclosure of arteries after percutaneous transluminal balloon angioplasty. A radiofrequency (rf) balloon catheter was used to perform thermal balloon angioplasty on canine arteries in vivo. The histologic appearance of rf-treated sites was compared with that of control sites treated by conventional percutaneous transluminal angioplasty. Acutely, rf-treated sites showed a reduced medial cellularity with preservation of internal elastic lamina except at the transitional zone between thermal injury and normal artery, where localized internal elastic lamina disruption was found. Nonthermal sites showed generalized disruption of internal elastic lamina and normal medial cellularity. Both thermal and nonthermal sites displayed a return of intimal cover commencing at 1 to 2 weeks and completed by 4 weeks. Diffuse myointimal hyperplasia appeared by 2 weeks after injury at breaks in the internal elastic lamina along the nonthermal vessels but was localized to the transitional zone in thermal injury sites. In rf-treated vessels, repopulation of the acellular thermally modified media had commenced by 4 weeks, and by 8 weeks the media was diffusely repopulated by spindle-shaped cells resembling smooth muscle cells lying between and aligned with preserved connective tissue laminae. Overall, the distribution and extent of the proliferative response after rf thermal balloon angioplasty were less than those seen after nonthermal balloon angioplasty. Thermal sites, which underwent reintimalization before medial cells returned, were considerably less prone to the development of myointimal hyperplasia. These results suggest that this modality may have beneficial effects on arterial healing after angioplasty.

  19. Effect of low-grade conductive heating on vascular compliance during in vitro balloon angioplasty. (United States)

    Mitchel, J F; Fram, D B; Aretz, T A; Gillam, L D; Woronick, C; Waters, D D; McKay, R G


    Radiofrequency-powered, thermal balloon angioplasty is a new technique that enhances luminal dilatation with less dissection than conventional angioplasty. The purpose of this study was to assess the effect of radiofrequency heating of balloon fluid on the pressure-volume mechanics of in vitro balloon angioplasty and to determine the histologic basis for thermal-induced compliance changes. In vitro, radiofrequency-powered, thermal balloon angioplasty was performed on 46 paired iliac segments freshly harvested from 23 nonatherosclerotic pigs. Balloon inflations at 60 degrees C were compared to room temperature inflations in paired arterial segments. Intraballoon pressure and volume were recorded during each inflation as volume infusion increased pressure over a 0 to 10 atm range. Pressure-volume compliance curves were plotted for all dilatations. Six segments were stained to assess the histologic abnormalities associated with thermal compliance changes. Radiofrequency heating acutely shifted the pressure-volume curves rightward in 20 of 23 iliac segments compared to nonheated controls. This increase in compliance persisted after heating and exceeded the maximum compliance shift caused by multiple nonheated inflations in a subset of arterial segments. Histologically, heated segments showed increased thinning and compression of the arterial wall, increased medial cell necrosis and altered elastic tissue fibers compared to nonheated specimens. In conclusion, radiofrequency heating of intraballoon fluid to 60 degrees C acutely increases vascular compliance during in vitro balloon angioplasty of nonatherosclerotic iliac arteries. The increased compliance persists after heating and can be greater than the compliance shifts induced by multiple conventional dilatations. Arterial wall thinning and irreversible alteration of elastic tissue fibers probably account for thermal compliance changes.

  20. Coriolis Mass-Flowmeter for aerostatic gas amount determination in zero pressure stratosperic balloons. (United States)

    Behar, Jean-Baptiste


    The CNES ballooning community regularly operates zero pressure balloons in many countries around the world (recently in France, Sweden, Canada and soon, Australia in 2017). An important operational flight parameter is the aerostatic gas mass injected into the balloon (currently helium and hydrogen in the study). Besides the lifting force, it determines mainly the ascent rate from which the adiabatic expansion depends directly. A too high ascent velocity in very cold air temperature profiles could result in a gas temperature drop which if too great, might induce brittleness of the envelope. A precise gas mass determination is therefore critical for performance as well as for mission safety. The various gas supply tanks in various countries all have different characteristics with possible uncertainties with regard to their volumes. This makes the currently used gas mass determination method based on supply tank pressure measurements unreliable. This method also relies on tank temperature, another source of inaccuracy in the gas amount determination. CNES has therefore prospected for alternative methods to reduce inaccuracies and perhaps also ease the operational procedures during balloon inflation. Coriolis mass-flowmeters which have reached industrial maturity, offer the great advantage over other flowmeters to be able to directly measure the mass of the transferred fluid, and not deducing it from other parameters as other types of flowmeters would do. An industrial contractor has been therefore assigned to integrate this solution into the CNES operational setup. This new system is to be tested in February 2016. The presentation will briefly explain the Coriolis flowmeter's principle and display the February 2016 performance tests' results. The expected incidence on zero pressure balloons' trajectories will also be discussed based on simulations ran on a balloon flight simulator software.