Sample records for accumulator ring vacuum

  1. Construction of vacuum system for Tristan accumulation ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ishimaru, H.; Horikoshi, G.; Kobayashi, M.

    1983-08-01

    An all aluminum-alloy vacuum system for the TRISTAN accumulation ring is now under construction. Aluminum and aluminum alloys are preferred materials for ultrahigh vacuum systems of large electron storage rings because of their good thermal conductivity, extremely low outgassing rate, and low residual radioactivity. Vacuum beam chambers for the dipole and quadrupole magnets are extruded using porthole dies. The aluminum alloy 6063-T6 provides superior performance in extrusion. For ultrahigh vacuum performance, a special extrusion technique is applied which, along with the outgassing procedure used, is described in detail. Aluminum alloy 3004 seamless elliptical bellows are inserted between the dipole andmore » quadrupole magnet chambers. These bellows are produced by the hydraulic forming of a seamless tube. The seamless bellows and the beam chambers are joined by fully automatic welding. The ceramic chambers for the kicker magnets, the fast bump magnets, and the slow beam intensity monitor are inserted in the aluminum alloy beam chambers. The ceramic chamber (98% alumina) and elliptical bellows are brazed with brazing sheets (4003-3003-4003) in a vacuum furnace. The brazing technique is described. The inner surface of the ceramic chamber is coated with a TiMo alloy by vacuum evaporation to permit a smooth flow of the RF wall current. Other suitable aluminum alloy components, including fittings, feedthroughs, gauges, optical windows, sputter ion pumps, turbomolecular pumps, and valves have been developed; their fabrication is described.« less

  2. Diffraction-limited storage-ring vacuum technology

    PubMed Central

    Al-Dmour, Eshraq; Ahlback, Jonny; Einfeld, Dieter; Tavares, Pedro Fernandes; Grabski, Marek

    2014-01-01

    Some of the characteristics of recent ultralow-emittance storage-ring designs and possibly future diffraction-limited storage rings are a compact lattice combined with small magnet apertures. Such requirements present a challenge for the design and performance of the vacuum system. The vacuum system should provide the required vacuum pressure for machine operation and be able to handle the heat load from synchrotron radiation. Small magnet apertures result in the conductance of the chamber being low, and lumped pumps are ineffective. One way to provide the required vacuum level is by distributed pumping, which can be realised by the use of a non-evaporable getter (NEG) coating of the chamber walls. It may not be possible to use crotch absorbers to absorb the heat from the synchrotron radiation because an antechamber is difficult to realise with such a compact lattice. To solve this, the chamber walls can work as distributed absorbers if they are made of a material with good thermal conductivity, and distributed cooling is used at the location where the synchrotron radiation hits the wall. The vacuum system of the 3 GeV storage ring of MAX IV is used as an example of possible solutions for vacuum technologies for diffraction-limited storage rings. PMID:25177979

  3. ION EFFECTS IN THE APS PARTICLE ACCUMULATOR RING

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Calvey, J.; Harkay, K.; Yao, CY.

    2017-06-25

    Trapped ions in the APS Particle Accumulator Ring (PAR) lead to a positive coherent tune shift in both planes, which increases along the PAR cycle as more ions accumulate. This effect has been studied using an ion simulation code developed at SLAC. After modifying the code to include a realistic vacuum profile, multiple ionization, and the effect of shaking the beam to measure the tune, the simulation agrees well with our measurements. This code has also been used to evaluate the possibility of ion instabilities at the high bunch charge needed for the APS-Upgrade.

  4. National Synchrotron Light Source II storage ring vacuum systems

    DOE PAGES

    Hseuh, Hsiao-Chaun; Hetzel, Charles; Leng, Shuwei; ...

    2016-04-05

    The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. Also, the majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. Finally, thismore » paper presents the design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

  5. National Synchrotron Light Source II storage ring vacuum systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hseuh, Hsiao-Chaun, E-mail: hseuh@bnl.gov; Hetzel, Charles; Leng, Shuwei

    2016-05-15

    The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. The majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. This paper presents themore » design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

  6. Advanced Photon Source accelerator ultrahigh vacuum guide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, C.; Noonan, J.

    1994-03-01

    In this document the authors summarize the following: (1) an overview of basic concepts of ultrahigh vacuum needed for the APS project, (2) a description of vacuum design and calculations for major parts of APS, including linac, linac waveguide, low energy undulator test line, positron accumulator ring (PAR), booster synchrotron ring, storage ring, and insertion devices, and (3) cleaning procedures of ultrahigh vacuum (UHV) components presently used at APS.

  7. O-Ring sealing arrangements for ultra-high vacuum systems

    DOEpatents

    Kim, Chang-Kyo; Flaherty, Robert

    1981-01-01

    An all metal reusable O-ring sealing arrangement for sealing two concentric tubes in an ultra-high vacuum system. An O-ring of a heat recoverable alloy such as Nitinol is concentrically positioned between protruding sealing rings of the concentric tubes. The O-ring is installed between the tubes while in a stressed martensitic state and is made to undergo a thermally induced transformation to an austenitic state. During the transformation the O-ring expands outwardly and contracts inwardly toward a previously sized austenitic configuration, thereby sealing against the protruding sealing rings of the concentric tubes.

  8. Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dees, Craig

    2016-07-01

    A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

  9. DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    HE,P.; HSEUH,H.C.; MAPES,M.

    2001-06-18

    The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with {approximately}100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent resultsmore » were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented.« less

  10. Ejector/liquid ring pump provides <0. 30 mm Hg vacuum for polymerization vessel

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lockwood, A.; Gaines, A.

    1982-03-01

    Firestone Fibers and Textiles Company, a division of Firestone Tire and Rubber Company, manufactures tire and industrial yarns of polyester and nylon-6. Nylon-6 molding and extrusion resins are also produced at the plant in Hopewell, Virginia. The process for making polyester requires an extremely low vacuum on the polymerization reactor. A consistent polymerization vessel vacuum of 0.3 mm Hg is needed, but the existing vacuum source, a five-stage steam jet ejector, could only provide a 0.5 mm Hg level. Two options were considered when the company decided to replace the original system with a system designed for 0.15 mm Hgmore » with a non-condensible gas load of 10.8 lb/hr. A new five-stage jet ejector system to meet these requirements would use 1395 lb/hr of 100 psig steam. The other option was a hybrid vacuum source composed of a three-stage steam ejector system and a liquid ring vacuum pump that is more energy efficient than ejectors for low vacuum applications. The hybrid system was selected because the three-stage jet ejector would use only 1240 lb/hr of 100 psig steam. The liquid ring vacuum pump would increase the material and installation cost of the system by about $4000, but the savings in steam consumption would pay back the added cost in less than two years. The jet ejector/liquid ring vacuum pump system has provided both the capacity and the extremely low vacuum needed for the polyester polymerization vessel, after making a small modification. The hybrid vacuum source is reliable, requires only routine maintenance, and will contiue to save substantial amounts of steam each year compared to the five-stage steam jet ejector.« less

  11. Beam vacuum system of Brookhaven`s muon storage ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hseuth, H.C.; Snydstrup, L.; Mapes, M.

    1995-11-01

    A storage ring with a circumference of 45 m is being built at Brookhaven to measure the g-2 value of the muons to an accuracy of 0.35 ppm.. The beam vacuum system of the storage ring will operate at 10{sup -7} Torr and has to be completely non-magnetic. It consists of twelve sector chambers. The chambers are constructed of aluminum and are approximately 3.5 m in length with a rectangular cross-section of 16.5 cm high by 45 cm at the widest point. The design features, fabrication techniques and cleaning methods for these chambers are described. The beam vacuum system willmore » be pumped by forty eight non-magnetic distributed ion pumps with a total pumping speed of over 2000 {ell}/sec. Monte Carlo simulations of the pressure distribution in the muon storage region are presented.« less

  12. Characteristics of ring type traveling wave ultrasonic motor in vacuum.

    PubMed

    Qu, Jianjun; Zhou, Ningning; Tian, Xiu; Jin, Long; Xu, Zhike

    2009-03-01

    The characteristics of ultrasonic motor strongly depend on the properties of stator/rotor contact interface which are affected by ambient environment. With the developed apparatus, load properties of two ring type traveling wave ultrasonic motors in atmosphere, low vacuum and high vacuum were studied, respectively. Wear of friction material, variations of vacuum degree and the temperature of motor during the experiment were also measured. The results show that load properties of motor A in vacuum were poorer than those in atmosphere, when load torque M(f) was less than 0.55 N m. Compared to motor A, load properties of motor B were affected a little by environmental pressure. Wear of friction material in vacuum was more severe than wear in atmosphere. The temperature of motor in vacuum rose more quickly than it in atmosphere and had not reached equilibrium in 2 h experiment. However, the temperature of motor in atmosphere had reached equilibrium in about forth minutes. Furthermore, outgas was also observed during experiment under vacuum conditions.

  13. Multiple internal seal ring micro-electro-mechanical system vacuum packaging method

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Shcheglov, Kirill V. (Inventor); Bae, Youngsam (Inventor); Wiberg, Dean V. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2008-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum packaging method that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  14. Status of NSLS-II Storage Ring Vacuum Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Doom,L.; Hseuh,H.; Ferreira, M.

    2009-05-04

    National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3-GeV, high-flux and high- brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system will have extruded aluminium chambers with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers will be used to intercept the un-used bending magnet radiation. In-situ bakeout will be implemented to achieve fast conditioning during initial commissioning and after interventions.

  15. Conditioning of the vacuum system of the TPS storage ring without baking in situ

    NASA Astrophysics Data System (ADS)

    Chan, C. K.; Chang, C. C.; Shueh, C.; Yang, I. C.; Wu, L. H.; Chen, B. Y.; Cheng, C. M.; Huang, Y. T.; Chuang, J. Y.; Cheng, Y. T.; Hsiao, Y. M.; Sheng, Albert

    2017-04-01

    To shorten the machine downtime, a maintenance procedure without baking in situ has been developed and applied to maintain and to upgrade the vacuum system of the TPS storage ring. The data of photon-stimulated desorption (PSD) reveal no obvious discrepancy between baking and not baking the vacuum system in situ. A beam-conditioning dose of extent only 11.8 A h is required to recover quickly the dynamic pressure of an unbaked vacuum system to its pre-intervention value according to the TPS maintenance experience.

  16. Measurement of the accumulation of water ice on optical components in cryogenic vacuum environments

    NASA Astrophysics Data System (ADS)

    Moeller, Trevor M.; Montgomery Smith, L.; Collins, Frank G.; Labello, Jesse M.; Rogers, James P.; Lowry, Heard S.; Crider, Dustin H.

    2012-11-01

    Standard vacuum practices mitigate the presence of water vapor and contamination inside cryogenic vacuum chambers. However, anomalies can occur in the facility that can cause the accumulation of amorphous water ice on optics and test articles. Under certain conditions, the amorphous ice on optical components shatters, which leads to a reduction in signal or failure of the component. An experiment was performed to study and measure the deposition of water (H2O) ice on optical surfaces under high-vacuum cryogenic conditions. Water was introduced into a cryogenic vacuum chamber, via a hydrated molecular sieve zeolite, through an effusion cell and impinged upon a quartz-crystal microbalance (QCM) and first-surface gold-plated mirror. A laser and photodiode setup, external to the vacuum chamber, monitored the multiple-beam interference reflectance of the ice-mirror configuration while the QCM measured the mass deposition. Data indicates that water ice, under these conditions, accumulates as a thin film on optical surfaces to thicknesses over 45 microns and can be detected and measured by nonintrusive optical methods which are based upon multiple-beam interference phenomena. The QCM validated the interference measurements. This experiment established proof-of-concept for a miniature system for monitoring ice accumulation within the chamber.

  17. Loss-free method of charging accumulator rings

    DOEpatents

    Maschke, Alfred W.

    1979-01-01

    A method for the production of high current pulses of heavy ions having an atomic weight greater than 100. Also a linear accelerator based apparatus for carrying out said method. Pulses formed by the method of the subject invention are suitable for storage in a storage ring. The accumulated pulses may be used in inertial fusion apparatus.

  18. Wafer-level hermetic vacuum packaging by bonding with a copper-tin thin film sealing ring

    NASA Astrophysics Data System (ADS)

    Akashi, Teruhisa; Funabashi, Hirofumi; Takagi, Hideki; Omura, Yoshiteru; Hata, Yoshiyuki

    2018-04-01

    A wafer-level hermetic vacuum packaging technology intended for use with MEMS devices was developed based on a copper-tin (CuSn) thin film sealing ring. To allow hermetic packaging, the shear strength of the CuSn thin film bond was improved by optimizing the pretreatment conditions. As a result, an average shear strength of 72.3 MPa was obtained and a cavity that had been hermetically sealed using wafer-level packaging (WLP) maintained its vacuum for 1.84 years. The total pressures in the cavities and the partial pressures of residual gases were directly determined with an ultra-low outgassing residual gas analyzer (RGA) system. Hermeticity was evaluated based on helium leak rates, which were calculated from helium pressures determined with the RGA system. The resulting data showed that a vacuum cavity following 1.84 years storage had a total pressure of 83.1 Pa, contained argon as the main residual gas and exhibited a helium leak rate as low as 1.67  ×  10-17 Pa · m3 s-1, corresponding to an air leak rate of 6.19  ×  10-18 Pa · m3 s-1. The RGA data demonstrate that WLP using a CuSn thin film sealing ring permits ultra-high hermeticity in conjunction with long-term vacuum packaging that is applicable to MEMS devices.

  19. Transverse beam stability measurement and analysis for the SNS accumulator ring

    DOE PAGES

    Xie, Zaipeng; Deibele, Craig; Schulte, Michael J.; ...

    2015-07-01

    In a Field-programmable gate array (FPGA) based transverse feedback damper system we implemented in the Spallation Neutron Source (SNS) accumulator ring with the intention to stabilize the electron-proton (e-p) instability in a frequency range from 1 MHz to 300 MHz. The transverse damper could also be used as a diagnostic tool by measuring the beam transfer function (BTF). An analysis of the BTF measurement provides the stability diagram for the production beam at SNS. Our paper describes the feedback damper system and its set-up as the BTF diagnostic tool. Experimental BTF results are presented and beam stability analysis is performedmore » based on the BTF measurements for the SNS accumulator ring.« less

  20. Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stillwell, B.; Billett, B.; Brajuskovic, B.

    2017-06-20

    Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction and rf cavity straight sections. An overview of progress in these areas is presented.

  1. Introduction to the magnet and vacuum systems of an electron storage ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Weng, W.T.

    An accelerator or storage ring complex is a concerted interplay of various functional systems. For the convenience of discussion we can divide it into the following systems: injector, magnet, RF, vacuum, instrumentation and control. In addition, the conventional construction of the building and radiation safety consideration are also needed and finally the beam lines, detector, data acquisition and analysis set-ups for research programs. Dr. L. Teng has given a comprehensive review of the whole complex and the operation of such a facility. I concentrate on the description of magnet and vacuum systems. Only the general function of each system andmore » the basic design concepts will be introduced, no detailed engineering practice will be given which will be best done after a machine design is produced. For further understanding and references a table of bibliography is provided at the end of the paper.« less

  2. Damping the e-p instability in the SNS accumulator ring

    NASA Astrophysics Data System (ADS)

    Evans, N. J.; Deibele, C.; Aleksandrov, A.; Xie, Z.

    2018-03-01

    A broadband, digital damper system for both transverse planes developed for the SNS accumulator ring has recently damped the first indications of the broadband 50-150 MHz e-p instability in a 1.2 MW neutron production beam. This paper presents details of the design and operation of the SNS damper system as well as results of active damping of the e-p instability in the SNS ring showing a reduction in power of betatron oscillation over the 10-300 MHz band of up to 70%. The spectral content of the beam during operation, with and without the damper system is presented and performance of the damper system is evaluated.

  3. Beamline front end for in-vacuum short period undulator at the photon factory storage ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miyauchi, Hiroshi, E-mail: hiroshi.miyauchi@kek.jp; Department of Accelerator Science, School of High Energy Accelerator Science, SOKENDAI; Tahara, Toshihiro, E-mail: ttahara@post.kek.jp

    The straight-section upgrade project of the Photon Factory created four new short straight sections capable of housing in-vacuum short period undulators. The first to fourth short period undulators SGU#17, SGU#03, SGU#01 and SGU#15 were installed at the 2.5-GeV Photon Factory storage ring in 2005, 2006, 2009 and 2013, respectively. The beamline front end for SGU#15 is described in this paper.

  4. REQUIREMENTS AND GUIDELINES FOR NSLS EXPERIMENTAL BEAM LINE VACUUM SYSTEMS-REVISION B.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    FOERSTER,C.

    Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas aftermore » a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware downstream

  5. Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stillwell, B.; Brajuskovic, B.; Carter, J.

    A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Up-grade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation; insufficient beam position monitor stability; excessive beam impedance; excessive heating by induced electrical surface currents; and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mockup assemblies; performing mechanical testing of chamber weld joints; developing computational tools; investigating design alternatives; and performing electrical bench measurements. Status of these activities andmore » some of what has been learned to date will be shared.« less

  6. The special features of tree ring gas chronologies

    NASA Astrophysics Data System (ADS)

    Ageev, Boris G.; Gruzdev, Aleksandr N.; Sapozhnikova, Valeria A.

    2015-11-01

    Stem wood is known to contain significant amounts of gases. However, literature data on the functional role of the gases are lacking. The results of our experiments show that porous wood structure is capable of annual accumulation (sorption) of the stem gas components that include H2O vapor and plant cell-respired CO2. This allows for development of additional chronologies to be used for gaining a deeper insight into the behavior of the stem gases. An analysis of the vacuum-extracted wood tree ring CO2 and H2O has revealed that the CO2 and H2O chronologies are associated with interannual variations in the total pressure of the gas components in the tree rings and are characterized by short-period cycles independent of tree age and by long-period variations with tree age. Our investigations led us to propose a procedure for using the CO2 content as a marker of year-to-year variations in the total pressure of the residual gas components found in wood tree rings.

  7. NSLS II Vacuum System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ferreira, M.; Doom, L.; Hseuh, H.

    2009-09-13

    National Synchrotron Light Source II, being constructed at Brookhaven, is a 3-GeV, 500 mA, 3rd generation synchrotron radiation facility with ultra low emittance electron beams. The storage ring vacuum system has a circumference of 792 m and consists of over 250 vacuum chambers with a simulated average operating pressure of less than 1 x 10{sup -9} mbar. A summary of the update design of the vacuum system including girder supports of the chambers, gauges, vacuum pumps, bellows, beam position monitors and simulation of the average pressure will be shown. A brief description of the techniques and procedures for cleaning andmore » mounting the chambers are given.« less

  8. Feed-through connector couples RF power into vacuum chamber

    NASA Technical Reports Server (NTRS)

    Grandy, G. L.

    1967-01-01

    Feed-through device connects RF power to an RF coil in a vacuum chamber. The coil and leads are water cooled and vacuum tight seals are provided at the junctions. The device incorporates silver soldered copper tubes, polytetrafluoroethylene electrical insulators, and O-ring vacuum seals.

  9. Observations of Space Charge effects in the Spallation Neutron Source Accumulator Ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Potts III, Robert E; Cousineau, Sarah M; Holmes, Jeffrey A

    2012-01-01

    The Spallation Neutron Source accumulator ring was designed to allow independent control of the transverse beam distribution in each plane. However, at high beam intensities, nonlinear space charge forces can strongly influence the final beam distribution and compromise our ability to independently control the transverse distributions. In this study we investigate the evolution of the beam at intensities of up to ~8x10^13 ppp through both simulation and experiment. Specifically, we analyze the evolution of the beam distribution for beams with different transverse aspect ratios and tune splits. We present preliminary results of simulations of our experiments.

  10. Partial-Vacuum-Gasketed Electrochemical Corrosion Cell

    NASA Technical Reports Server (NTRS)

    Bonifas, Andrew P.; Calle, Luz M.; Hintze, Paul E.

    2006-01-01

    An electrochemical cell for making corrosion measurements has been designed to prevent or reduce crevice corrosion, which is a common source of error in prior such cells. The present cell (see figure) includes an electrolyte reservoir with O-ring-edged opening at the bottom. In preparation for a test, the reservoir, while empty, is pressed down against a horizontal specimen surface to form an O-ring seal. A purge of air or other suitable gas is begun in the reservoir, and the pressure in the reservoir is regulated to maintain a partial vacuum. While maintaining the purge and partial vacuum, and without opening the interior of the reservoir to the atmosphere, the electrolyte is pumped into the reservoir. The reservoir is then slowly lifted a short distance off the specimen. The level of the partial vacuum is chosen such that the differential pressure is just sufficient to keep the electrolyte from flowing out of the reservoir through the small O-ring/specimen gap. Electrochemical measurements are then made. Because there is no gasket (and, hence, no crevice between the specimen and the gasket), crevice corrosion is unlikely to occur.

  11. Surface charge accumulation of solid insulator under nanosecond pulse in vacuum: 3D distribution features and mechanism

    NASA Astrophysics Data System (ADS)

    Qi, Bo; Gao, Chunjia; Sun, Zelai; Li, Chengrong

    2017-11-01

    Surface charge accumulation can incur changes in electric field distribution, involved in the electron propagation process, and result in a significant decrease in the surface flashover voltage. The existing 2D surface charge measurement fails to meet the actual needs in real engineering applications that usually adopt the 45° conical frustum insulators. The present research developed a novel 3D measurement platform to capture surface charge distribution on solid insulation under nanosecond pulse in a vacuum. The results indicate that all surface charges are positive under a positive pulse and negative under a negative pulse. Surface charges tend to accumulate more near the upper electrode. Surface charge density increases significantly with the increase in pulse counts and amplitudes. Accumulation of surface charge results in a certain decrease of flashover voltage. Taking consideration of the secondary electron emission for the surface charge accumulation, four materials were obtained to demonstrate the effects on surface charge. Combining the effect incurred by secondary electron emission and the weighty action taken by surface charge accumulation on the flashover phenomena, the discharge mechanism along the insulator surface under nanosecond pulse voltage was proposed.

  12. In-Vacuum Dissociator for Atomic-Hydrogen Masers

    NASA Technical Reports Server (NTRS)

    Vessot, R. F.

    1987-01-01

    Thermal control and vacuum sealing achieved while contamination avoided. Simple, relatively inexpensive molecular-hydrogen dissociator for atomic-hydrogen masers used on Earth or in vacuum of space. No air cooling required, and absence of elastomeric O-ring seals prevents contamination. In-vacuum dissociator for atomic hydrogen masers, hydrogen gas in glass dissociator dissociated by radio-frequency signal transmitted from surrounding 3-turn coil. Heat in glass conducted away by contacting metal surfaces.

  13. Ultra high vacuum seal arrangement

    DOEpatents

    Flaherty, Robert

    1981-01-01

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  14. Vacuum encapsulated hermetically sealed diamond amplified cathode capsule and method for making same

    DOEpatents

    Rao, Triveni; Walsh, John; Gangone, Elizabeth

    2014-12-30

    A vacuum encapsulated, hermetically sealed cathode capsule for generating an electron beam of secondary electrons, which generally includes a cathode element having a primary emission surface adapted to emit primary electrons, an annular insulating spacer, a diamond window element comprising a diamond material and having a secondary emission surface adapted to emit secondary electrons in response to primary electrons impinging on the diamond window element, a first cold-weld ring disposed between the cathode element and the annular insulating spacer and a second cold-weld ring disposed between the annular insulating spacer and the diamond window element. The cathode capsule is formed by a vacuum cold-weld process such that the first cold-weld ring forms a hermetical seal between the cathode element and the annular insulating spacer and the second cold-weld ring forms a hermetical seal between the annular spacer and the diamond window element whereby a vacuum encapsulated chamber is formed within the capsule.

  15. Force on a storage ring vacuum chamber after sudden turn-off of a magnet power supply

    NASA Astrophysics Data System (ADS)

    Sinha, Gautam; Prabhu, S. S.

    2011-10-01

    We are commissioning a 2.5 GeV synchrotron radiation source (SRS) where electrons travel in high vacuum inside the vacuum chambers made of aluminum alloys. These chambers are kept between the pole gaps of magnets and are made to facilitate the radiation coming out of the storage ring to the experimental station. These chambers are connected by metallic bellows. During the commissioning phase of the SRS, the metallic bellows became ruptured due to the frequent tripping of the dipole magnet power supply. The machine was down for quite some time. In the case of a power supply trip, the current in the magnets decays exponentially. It was observed experimentally that the fast B field decay generates a large eddy current in the chambers and consequently the chambers are subjected to a huge Lorentz force. This motivated us to develop a theoretical model to study the force acting on a metallic plate when exposed to an exponentially decaying field and then to extend it for a rectangular vacuum chamber. The problem is formulated using Maxwell’s equations and converted to the inhomogeneous Helmholtz equation. After taking the Laplace transform, the equation is solved with appropriate boundary conditions. Final results are obtained after taking the appropriate inverse Laplace transform. The expressions for eddy current contour and magnetic field produced by the eddy current are also derived. Variations of the force on chambers of different wall thickness due to spatially varying and exponentially time decaying field are presented. The result is a general theory which can be applied to different geometries and calculation of power loss as well. Comparisons are made with results obtained by simulation using a finite element based code, for quick verification of the theoretical model.

  16. Rugged Preheaters For Vacuum Plasma Spraying

    NASA Technical Reports Server (NTRS)

    Woodford, William H.; Mckechnie, Timothy N.; Sander, Lewis D.; Power, Christopher A.; Sander, Heather L.; Nguyen, Dalton D.

    1994-01-01

    Electric preheater units built to ensure large workpieces to be coated with metals by vacuum plasma spraying heated uniformly to requisite high temperatures by time plasma torch arrives. Units similar to electrical-resistance ribbon heaters in toasters and in some small portable electric "space" heaters. Nichrome resistance-heating ribbons wrapped around ceramic insulating spools on rings and on plates. Round workpiece placed in middle of ring preheater. Plate preheaters stacked as needed near workpiece.

  17. Rubber-coated bellows improves vibration damping in vacuum lines

    NASA Technical Reports Server (NTRS)

    Hegland, D. E.; Smith, R. J.

    1966-01-01

    Compact-vibration damping systems, consisting of rubber-coated metal bellows with a sliding O-ring connector, are used in vacuum lines. The device presents a metallic surface to the vacuum system and combines flexibility with the necessary stiffness. It protects against physical damage, reduces fatigue failure, and provides easy mating of nonparallel lines.

  18. Note: O-ring stack system for electron gun alignment.

    PubMed

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.

  19. Vacuum solutions of five dimensional Einstein equations generated by inverse scattering method. II. Production of the black ring solution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tomizawa, Shinya; Nozawa, Masato

    2006-06-15

    We study vacuum solutions of five-dimensional Einstein equations generated by the inverse scattering method. We reproduce the black ring solution which was found by Emparan and Reall by taking the Euclidean Levi-Civita metric plus one-dimensional flat space as a seed. This transformation consists of two successive processes; the first step is to perform the three-solitonic transformation of the Euclidean Levi-Civita metric with one-dimensional flat space as a seed. The resulting metric is the Euclidean C-metric with extra one-dimensional flat space. The second is to perform the two-solitonic transformation by taking it as a new seed. Our result may serve asmore » a stepping stone to find new exact solutions in higher dimensions.« less

  20. Caps Seal Boltholes On Vacuum-System Flanges

    NASA Technical Reports Server (NTRS)

    Roman, Robert F.

    1993-01-01

    Sealing caps devised for boltholes on vacuum-system flanges. Used in place of leak-prone gaskets, and provide solid metal-to-metal interfaces. Each sealing cap contains square-cut circular groove in which O-ring placed. Mounted on studs protruding into access ports, providing positive seal around each bolthole. Each cap mates directly with surface of flange, in solid metal-to-metal fit, with O-ring completely captured in groove. Assembly immune to misalignment, leakage caused by vibration, and creeping distortion caused by weight of port. O-ring material chosen for resistance to high temperature; with appropriate choice of material, temperature raised to as much as 315 degrees C.

  1. Note: O-ring stack system for electron gun alignment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, In-Yong; Cho, Boklae; Han, Cheolsu

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignmentmore » and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.« less

  2. Analysis of RFQ vacuum system for HINS tests at MDB

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Piekarz, Henryk; /Fermilab

    The arrangement of RFQ vacuum system is briefly described. The projections of the vacuum level using standard out-gassing rates for the RFQ major components are compared with measurements. The permeation of water through the Viton O-rings of the LCW manifold inside the RFQ vacuum vessel is analyzed and compared with RGA data. A model where the out-gassing water from the vanes inner surfaces affects seriously RFQ operation is devised and compared with RFQ performance. The rate of a hydrogen gas spill from the LEBT into the RFQ vacuum space is also projected. Suggestions to correct and improve RFQ operation aremore » presented.« less

  3. Consequences of plasma oxidation and vacuum annealing on the chemical properties and electron accumulation of In2O3 surfaces

    NASA Astrophysics Data System (ADS)

    Berthold, Theresa; Rombach, Julius; Stauden, Thomas; Polyakov, Vladimir; Cimalla, Volker; Krischok, Stefan; Bierwagen, Oliver; Himmerlich, Marcel

    2016-12-01

    The influence of oxygen plasma treatments on the surface chemistry and electronic properties of unintentionally doped and Mg-doped In2O3(111) films grown by plasma-assisted molecular beam epitaxy or metal-organic chemical vapor deposition is studied by photoelectron spectroscopy. We evaluate the impact of semiconductor processing technology relevant treatments by an inductively coupled oxygen plasma on the electronic surface properties. In order to determine the underlying reaction processes and chemical changes during film surface-oxygen plasma interaction and to identify reasons for the induced electron depletion, in situ characterization was performed implementing a dielectric barrier discharge oxygen plasma as well as vacuum annealing. The strong depletion of the initial surface electron accumulation layer is identified to be caused by adsorption of reactive oxygen species, which induce an electron transfer from the semiconductor to localized adsorbate states. The chemical modification is found to be restricted to the topmost surface and adsorbate layers. The change in band bending mainly depends on the amount of attached oxygen adatoms and the film bulk electron concentration as confirmed by calculations of the influence of surface state density on the electron concentration and band edge profile using coupled Schrödinger-Poisson calculations. During plasma oxidation, hydrocarbon surface impurities are effectively removed and surface defect states, attributed to oxygen vacancies, vanish. The recurring surface electron accumulation after subsequent vacuum annealing can be consequently explained by surface oxygen vacancies.

  4. Vacuum system for room temperature X-ray lithography source (XLS)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schuchman, J.C.

    1988-09-30

    A prototype room-temperature X-Ray Lithography Source (XLS)was proposed to be built at Brookhaven National Laboratory as part of a technology-transfer- to-American-industry program. The overall machine comprises a full energy linac, a 170 meter long transport line, and a 39 meter circumference storage ring. The scope of this paper will be limited to describing the storage ring vacuum system. (AIP)

  5. Vacuum system for room temperature X-ray lithography source (XLS)

    NASA Astrophysics Data System (ADS)

    Schuchman, J. C.

    1988-09-01

    A prototype room-temperature X-Ray Lithography Source (XLS)was proposed to be built at Brookhaven National Laboratory as part of a technology-transfer- to-American-industry program. The overall machine comprises a full energy linac, a 170 meter long transport line, and a 39 meter circumference storage ring. The scope of this paper will be limited to describing the storage ring vacuum system. (AIP)

  6. The vacuum system reform and test of the super-critical 600mw unit

    NASA Astrophysics Data System (ADS)

    Yan, Tao; Wan, Zhonghai; Lu, Jin; Chen, Wen; Cai, Wen

    2017-11-01

    The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

  7. Iron-binding haemerythrin RING ubiquitin ligases regulate plant iron responses and accumulation

    PubMed Central

    Kobayashi, Takanori; Nagasaka, Seiji; Senoura, Takeshi; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Nishizawa, Naoko K.

    2013-01-01

    Iron is essential for most living organisms. Plants transcriptionally induce genes involved in iron acquisition under conditions of low iron availability, but the nature of the deficiency signal and its sensors are unknown. Here we report the identification of new iron regulators in rice, designated Oryza sativa Haemerythrin motif-containing Really Interesting New Gene (RING)- and Zinc-finger protein 1 (OsHRZ1) and OsHRZ2. OsHRZ1, OsHRZ2 and their Arabidopsis homologue BRUTUS bind iron and zinc, and possess ubiquitination activity. OsHRZ1 and OsHRZ2 are susceptible to degradation in roots irrespective of iron conditions. OsHRZ-knockdown plants exhibit substantial tolerance to iron deficiency, and accumulate more iron in their shoots and grains irrespective of soil iron conditions. The expression of iron deficiency-inducible genes involved in iron utilization is enhanced in OsHRZ-knockdown plants, mostly under iron-sufficient conditions. These results suggest that OsHRZ1 and OsHRZ2 are iron-binding sensors that negatively regulate iron acquisition under conditions of iron sufficiency. PMID:24253678

  8. Vacuum packing: a model system for laboratory-scale silage fermentations.

    PubMed

    Johnson, H E; Merry, R J; Davies, D R; Kell, D B; Theodorou, M K; Griffith, G W

    2005-01-01

    To determine the utility of vacuum-packed polythene bags as a convenient, flexible and cost-effective alternative to fixed volume glass vessels for lab-scale silage studies. Using perennial ryegrass or red clover forage, similar fermentations (as assessed by pH measurement) occurred in glass tube and vacuum-packed silos over a 35-day period. As vacuum-packing devices allow modification of initial packing density, the effect of four different settings (initial packing densities of 0.397, 0.435, 0.492 and 0.534 g cm(-3)) on the silage fermentation over 16 days was examined. Significant differences in pH decline and lactate accumulation were observed at different vacuum settings. Gas accumulation was apparent within all bags and changes in bag volume with time was observed to vary according to initial packing density. Vacuum-packed silos do provide a realistic model system for lab-scale silage fermentations. Use of vacuum-packed silos holds potential for lab-scale evaluations of silage fermentations, allowing higher throughput of samples, more consistent packing as well as the possibility of investigating the effects of different initial packing densities and use of different wrapping materials.

  9. In-Situ Focusing Inside a Thermal Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Hannah, Brett; Bartman, Randall; Radulescu, Costin; Rud, Mayer; Sarkissian, Edwin; Ho, Timothy; {p; Esposito, Joseph; Sutin, Brian; hide

    2010-01-01

    Traditionally, infrared (IR) space instruments have been focused by iterating with a number of different thickness shim rings in a thermal vacuum chamber until the focus meets requirements. This has required a number of thermal cycles that are very expensive as they tie up many integration and test (I&T)/ environmental technicians/engi neers work ing three shifts for weeks. Rather than creating a test shim for each iteration, this innovation replaces the test shim and can focus the instrument while in the thermal vacuum chamber. The focus tool consists of three small, piezo-actuated motors that drive two sets of mechanical interface flanges between the instrument optics and the focal- plane assembly, and three optical-displacement metrology sensors that can be read from outside the thermal vacuum chamber. The motors are used to drive the focal planes to different focal distances and acquire images, from which it is possible to determine the best focus. At the best focus position, the three optical displacement metrology sensors are used to determine the shim thickness needed. After the instrument leaves the thermal vacuum chamber, the focus tool is replaced with the precision-ground shim ring. The focus tool consists of two sets of collars, one that mounts to the backside of the interface flange of the instrument optics, and one that mounts to the backside of the interface flange of the focal plane modules. The collars on the instrument optics side have the three small piezo-actuated motors and the three optical displacement metrology systems. Before the instrument is focused, there is no shim ring in place and, therefore, no fasteners holding the focal plane modules to the cameras. Two focus tooling collars are held together by three strong springs. The Orbiting Carbon Observatory (OCO) mission spectrometer was focused this way (see figure). The motor described here had to be moved five times to reach an acceptable focus, all during the same thermal cycle, which

  10. [Dynamic characters of sulphur and heavy metals concentrations in Pinus taiwanensis growth rings].

    PubMed

    Wu, Zemin; Gao, Jian; Huang, Chenglin; Hong, Shuyuan

    2005-05-01

    Based on the concentration analyses of S, Mn, Fe, Zn, Cu and Pb in the growth ring set of Pinus taiwanensis at the summit (1,400-1,600 m alt.) of Huangshan Mountains during past 80 years, this paper studied the dynamic characters of element concentrations in the ring set, and their relationships with atmospheric environment. The results showed that there were three levels of S concentration in the growth ring set, i.e., low concentration (less than 2 mg.kg(-1)), accounted for 58.5% of the ring set; medium (3.65-6.0 mg.kg(-1)), accounted for 24.4%; and high ( > 11.0 mg.kg(-1)), accounted for 17.1%. The dynamic change of S accumulation in the ring set displayed an obvious fluctuation, which could be divided into 3 major types, i.e., fluctuation during 1917-1960, relatively stable during 1961-1980, and gradual increase after 1981. In the growth ring set of 1935-1938, 1959-1960, and recent 10 years, the S accumulation concentrations were all higher than 11 mg.kg(-1), suggesting the relatively high atmospheric S concentration in those periods. There was a significant correlation between the increase of tourist amount in Huangshan scenic spot and the S concentration in growth ring set. The fuel fume centralized in some places might result in the atmospheric pollution at local scale, which in turn, might influence the S accumulation in growth ring set. The Pb accumulation concentration in the ring set was less than the background value in soil. The accumulation concentrations of Mn, Fe, Zn and Cu showed fluctuation characteristics, with independence of each other. The accumulation of Zn and Cu in growth rings had no correlation with tree age, while that of Mn and Fe was in adverse. The Mn concentration in the growth ring set decreased with tree age but increased in recent growth rings, while the Fe concentration was on the contrary, which needed further study.

  11. Accelerated vacuum testing of long life ball bearings and sliprings

    NASA Technical Reports Server (NTRS)

    Meeks, C. R.; Christy, R. I.; Cunningham, A. C.

    1971-01-01

    Extensive analytical studies and testing have been conducted on bearings and sliprings in vacuum at temperatures from 30 to 130 F. Thirty-six bearings lubricated with two types of oil were tested in vacuum of less than 10 to the minus 8th power torr at speeds from 55 to 180 rpm. Temperatures, load, speed, and oil viscosity were varied to evaluate the effects on life and wear. All bearings performed successfully during a 7-month test, and the potential merits of the two oils were compared. Over 25 different, dry-lubricated brush/slipring material combinations have been tested, with variations of brush and ring design and surface speed. Test results indicate the probability of 10 years or more of slipring and brush lifetime with properly designed brushes for 1-in.-diameter ring rotating at 60 rpm.

  12. Multiple internal seal right micro-electro-mechanical system vacuum package

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill V. (Inventor); Wiberg, Dean V. (Inventor); Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Bae, Youngsam (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2007-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum package that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  13. Damping Ring R&D at CESR-TA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rubin, David L.

    2015-01-23

    Accelerators that collide high energy beams of matter and anti-matter are essential tools for the investigation of the fundamental constituents of matter, and the search for new forms of matter and energy. A “Linear Collider” is a machine that would bring high energy and very compact bunches of electrons and positrons (anti-electrons) into head-on collision. Such a machine would produce (among many other things) the newly discovered Higgs particle, enabling a detailed study of its properties. Among the most critical and challenging components of a linear collider are the damping rings that produce the very compact and intense beams ofmore » electrons and positrons that are to be accelerated into collision. Hot dilute particle beams are injected into the damping rings, where they are compressed and cooled. The size of the positron beam must be reduced more than a thousand fold in the damping ring, and this compression must be accomplished in a fraction of a second. The cold compact beams are then extracted from the damping ring and accelerated into collision at high energy. The proposed International Linear Collider (ILC), would require damping rings that routinely produce such cold, compact and intense beams. The goal of the Cornell study was a credible design for the damping rings for the ILC. Among the technical challenges of the damping rings; the development of instrumentation that can measure the properties of the very small beams in a very narrow window of time, and mitigation of the forces that can destabilize the beams and prevent adequate cooling, or worse lead to beam loss. One of the most pernicious destabilizing forces is due to the formation of clouds of electrons in the beam pipe. The electron cloud effect is a phenomenon in particle accelerators in which a high density of low energy electrons, build up inside the vacuum chamber. At the outset of the study, it was anticipated that electron cloud effects would limit the intensity of the positron

  14. Squeezed pulsed light from a fiber ring interferometer

    NASA Technical Reports Server (NTRS)

    Bergman, K.; Haus, H. A.

    1992-01-01

    Observation of squeezed noise, 5 +/- 0.3 dB below the shot noise level, generated with pulses in a fiber ring interferometer is reported. The interferometric geometry is used to separate the pump pulse from the squeezed vacuum radiation. A portion of the pump is reused as the local oscillator in a homodyne detection. The pump fluctuations are successfully subtracted and shot noise limited performance is achieved at low frequencies (35-85 KHz). A possible utilization of the generated squeezed vacuum in improving a fiber gyro's signal to noise ratio is discussed.

  15. Design study for a liquid metal slip ring solar array orientation mechanism

    NASA Technical Reports Server (NTRS)

    Clark, R. B.

    1972-01-01

    The design of a single axis orientation mechanism for solar arrays on high power synchronous satellites is studied primarily with respect to providing 116 liquid metal slip rings for reduced friction and improved electrical characteristics. Designs and tradeoff studies for the slip rings and other components are presented. An assembly containing 33 slip rings of three design approaches was designed, fabricated, and vacuum tested to 30 amperes and 30,000 volts. Containment of the liquid metal gallium in large diameter slip rings was difficult. A design approach is presented which is expected to provide improved retention of the liquid metal.

  16. Properties of the electron cloud in a high-energy positron and electron storage ring

    DOE PAGES

    Harkay, K. C.; Rosenberg, R. A.

    2003-03-20

    Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in amore » positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Furthermore, such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.« less

  17. Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

    DOEpatents

    Bowers, Joel M.

    1994-01-01

    An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz.

  18. Saddle-shaped mitral valve annuloplasty rings experience lower forces compared with flat rings.

    PubMed

    Jensen, Morten O; Jensen, Henrik; Smerup, Morten; Levine, Robert A; Yoganathan, Ajit P; Nygaard, Hans; Hasenkam, J Michael; Nielsen, Sten L

    2008-09-30

    New insight into the 3D dynamic behavior of the mitral valve has prompted a reevaluation of annuloplasty ring designs. Force balance analysis indicates correlation between annulus forces and stresses in leaflets and chords. Improving this stress distribution can intuitively enhance the durability of mitral valve repair. We tested the hypothesis that saddle-shaped annuloplasty rings have superior uniform systolic force distribution compared with a nonuniform force distribution in flat annuloplasty rings. Sixteen 80-kg pigs had a flat (n=8) or saddle-shaped (n=8) mitral annuloplasty ring implanted. Mitral annulus 3D dynamic geometry was obtained with sonomicrometry before ring insertion. Strain gauges mounted on dedicated D-shaped rigid flat and saddle-shaped annuloplasty rings provided the intraoperative force distribution perpendicular to the annular plane. Average systolic annular height to commissural width ratio before ring implantation was 14.0%+/-1.6%. After flat and saddle shaped ring implantation, the annulus was fixed in the diastolic (9.0%+/-1.0%) and systolic (14.3%+/-1.3%) configuration, respectively (P<0.01). Force accumulation was seen from the anterior (0.72N+/-0.14N) and commissural annular segments (average 1.38N+/-0.27N) of the flat rings. In these segments, the difference between the 2 types of rings was statistically significant (P<0.05). The saddle-shaped annuloplasty rings did not experience forces statistically significantly larger than zero in any annular segments. Saddle-shaped annuloplasty rings provide superior uniform annular force distribution compared to flat rings and appear to represent a configuration that minimizes out-of-plane forces that could potentially be transmitted to leaflets and chords. This may have important implications for annuloplasty ring selections.

  19. Apple RING E3 ligase MdMIEL1 inhibits anthocyanin accumulation by ubiquitinating and degrading MdMYB1 protein.

    PubMed

    An, Jian-Ping; Liu, Xin; Li, Hao-Hao; You, Chun-Xiang; Wang, Xiao-Fei; Hao, Yu-Jin

    2017-11-01

    MdMYB1 is an important regulator for anthocyanin accumulation in apple (Malus × domestica). Here, an apple RING E3 ligase, MdMIEL1, was screened out as a partner of MdMYB1 with a yeast two-hybrid approach. Pull-down, bimolecular fluorescence complementation and coimmunoprecipitation assays further verified the interaction between MdMIEL1 and MdMYB1 proteins. Subsequently, in vitro and in vivo experiments indicated that MdMIEL1 functioned as a ubiquitin E3 ligase to ubiquitinate MdMYB1 protein, followed by degradation through a 26S proteasome pathway. Furthermore, transgenic studies in apple calli and Arabidopsis demonstrated that MdMIEL1 negatively regulated anthocyanin accumulation by modulating the degradation of MdMYB1 protein. Taken together, our findings provide a new insight into the molecular mechanism by which MdMIEL1 negatively regulates anthocyanin biosynthesis by ubiquitinating and degrading MdMYB1 protein. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  20. Refurbishment of a used in-vacuum undulator from the National Synchrotron Light Source for the National Synchrotron Light Source-II ring

    DOE PAGES

    Tanabe, Toshiya; Bassan, Harmanpreet; Broadbent, Andrew; ...

    2017-08-01

    The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS-II. There were four in-vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini-gap undulator (MGU-X25, to be renamed IVU18 for NSLS-II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS-II. At the time of construction, IVU18 was a state-of-the-art undulator designed to be operated as a cryogenic permanent-magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS-II ring,more » the transition region was redesigned. The control system was also updated to NSLS-II specifications. As a result, this paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning.« less

  1. Refurbishment of a used in-vacuum undulator from the National Synchrotron Light Source for the National Synchrotron Light Source-II ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tanabe, Toshiya; Bassan, Harmanpreet; Broadbent, Andrew

    The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS-II. There were four in-vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini-gap undulator (MGU-X25, to be renamed IVU18 for NSLS-II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS-II. At the time of construction, IVU18 was a state-of-the-art undulator designed to be operated as a cryogenic permanent-magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS-II ring,more » the transition region was redesigned. The control system was also updated to NSLS-II specifications. As a result, this paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning.« less

  2. Functional roles of the pepper RING finger protein gene, CaRING1, in abscisic acid signaling and dehydration tolerance.

    PubMed

    Lim, Chae Woo; Hwang, Byung Kook; Lee, Sung Chul

    2015-09-01

    Plants are constantly exposed to a variety of biotic and abiotic stresses, which include pathogens and conditions of high salinity, low temperature, and drought. Abscisic acid (ABA) is a major plant hormone involved in signal transduction pathways that mediate the defense response of plants to abiotic stress. Previously, we isolated Ring finger protein gene (CaRING1) from pepper (Capsicum annuum), which is associated with resistance to bacterial pathogens, accompanied by hypersensitive cell death. Here, we report a new function of the CaRING1 gene product in the ABA-mediated defense responses of plants to dehydration stress. The expression of the CaRING1 gene was induced in pepper leaves treated with ABA or exposed to dehydration or NaCl. Virus-induced gene silencing of CaRING1 in pepper plants exhibited low degree of ABA-induced stomatal closure and high levels of transpirational water loss in dehydrated leaves. These led to be more vulnerable to dehydration stress in CaRING1-silenced pepper than in the control pepper, accompanied by reduction of ABA-regulated gene expression and low accumulation of ABA and H2O2. In contrast, CaRING1-overexpressing transgenic plants showed enhanced sensitivity to ABA during the seedling growth and establishment. These plants were also more tolerant to dehydration stress than the wild-type plants because of high ABA accumulation, enhanced stomatal closure and increased expression of stress-responsive genes. Together, these results suggest that the CaRING1 acts as positive factor for dehydration tolerance in Arabidopsis by modulating ABA biosynthesis and ABA-mediated stomatal closing and gene expression.

  3. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    NASA Astrophysics Data System (ADS)

    Prasad, D. N.; Ayyappan, R.; Kamble, L. P.; Singh, J. P.; Muralikrishna, L. V.; Alex, M.; Balagi, V.; Mukhopadhyay, P. K.

    2008-05-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ~1 × 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mm×160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face & diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6×10-9 m bar ltr/sec in vacuum mode and 2×10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5×10-5 mbar, the new valve achieved vacuum 7.4×10-6mbar in the same time under the same conditions.

  4. Mysteries of the ringed planets. [colloquium review

    NASA Technical Reports Server (NTRS)

    Cuzzi, J. N.

    1982-01-01

    An assessment is presented of the recent progress in the theory of planetary rings which was in evidence at the IAU's recent, 75th Colloquium. Observational material was dominated by spacecraft data, and theoretical consideration of the problems posed comes predominantly from gravitational mechanics. An understanding of collective effects, in light of both fluid mechanical and statistical mechanical methodologies, is being approached, and the importance of electromagnetic phenomena studies is noted. Voyager observations of Saturn's rings, and accumulating data from stellar occultations by the rings of Uranus, provided most of the observational material. Jupiter's faint ring was closely examined by the 1979 Voyager flight. These three known ring systems are found to exhibit such family resemblances as their proximity to the parent planet and magnetospheric environment.

  5. Multi-hundred kilowatt roll ring assembly

    NASA Technical Reports Server (NTRS)

    Jacobson, Peter E.

    1985-01-01

    A program was completed to develop an evaluation unit of a high power rotary transfer device for potential application in a space environment. This device was configured around a Roll Ring concept which performs the same function as a slip ring/brush assembly with a rolling instead of sliding interface. An eight circuit Evaluation Unit (EU) and a portable Test Fixture (TF) were designed and fabricated. The EU was designed to transfer currents to 200 amperes at a potential of as high as 500 volts for an ultimate 100 kW/circuit transfer capability. The EU was evaluated in vacuum at dc transfer currents of 50 to 200 amperes at voltages to 10 volts and at 500 volts at 2 amperes. Power transfer to levels of 2 kW through each of the eight circuits was completed. Power transfer in vacuum at levels and efficiencies not previously achieved was demonstrated. The terminal-to-terminal resistance was measured to be greater than 0.42 milliohms which translates to an efficiency at 100 kW of 99.98 percent. The EU and TF have been delivered to the Lewis Research Center and are being prepared tor testing at increased power levels and for life testing, which will include both dc and ac power.

  6. Evacuated optical structure comprising optical bench mounted to sidewall of vacuum chamber in a manner which inhibits deflection and rotation of the optical bench

    DOEpatents

    Bowers, J.M.

    1994-04-19

    An improved evacuated optical structure is disclosed comprising an optical bench mounted in a vacuum vessel in a manner which inhibits transmission of movement of the vacuum vessel to the optical bench, yet provides a compact and economical structure. The vacuum vessel is mounted, through a sidewall thereof, to a support wall at four symmetrically positioned and spaced apart areas, each of which comprises a symmetrically positioned group of mounting structures passing through the sidewall of the vacuum vessel. The optical bench is pivotally secured to the vacuum vessel by four symmetrically spaced apart bolts and spherical bearings, each of which is centrally positioned within one of the four symmetrically positioned groups of vacuum vessel mounting structures. Cover plates and o-ring seals are further provided to seal the vacuum vessel mounting structures from the interior of the vacuum vessel, and venting bores are provided to vent trapped gases in the bores used to secure the cover plates and o-rings to the vacuum vessel. Provision for detecting leaks in the mounting structures from the rear surface of the vacuum vessel sidewall facing the support wall are also provided. Deflection to the optical bench within the vacuum vessel is further minimized by tuning the structure for a resonant frequency of at least 100 Hertz. 10 figures.

  7. Assessment of neutron skyshine near unmodified Accumulator Debuncher storage rings under Mu2e operational conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cossairt, J.Donald; /Fermilab

    2010-12-01

    Preliminary plans for providing the proton beam needed by the proposed Mu2e experiment at Fermilab will require the transport of 8 GeV protons to the Accumulator/Debuncher where they be processed into an intensity and time structure useful for the experiment. The intensities involved are far greater that those encountered with antiprotons of the same kinetic energy in the same beam enclosures under Tevatron Collider operational conditions, the operating parameters for which the physical facilities of the Antiproton Source were designed. This note explores some important ramifications of the proposed operation for radiation safety and demonstrates the need for extensive modificationsmore » of significant portions of the shielding of the Accumulator Debuncher storage rings; notably that underneath the AP Service Buildings AP10, AP30, and AP50. While existing shielding is adequate for the current operating mode of the Accumulator/Debuncher as part of the Antiproton Source used in the Tevatron Collider program, without significant modifications of the shielding configuration in the Accumulator/Debuncher region and/or beam loss control systems far more effective than seen in most applications at Fermilab, the proposed operational mode for Mu2e is not viable for the following reasons: 1. Due to skyshine alone, under normal operational conditions large areas of the Fermilab site would be exposed to unacceptable levels of radiation where most of the Laboratory workforce and some members of the general public who regularly visit Fermilab would receive measurable doses annually, contrary to workforce, public, and DOE expectations concerning the As Low as Reasonably Achievable (ALARA) principle. 2. Under normal operational conditions, a sizeable region of the Fermilab site would also require fencing due to skyshine. The size of the areas involved would likely invite public inquiry about the significant and visible enlargement of Fermilab's posted radiological areas. 3

  8. The Storage Ring Proton EDM Experiment

    NASA Astrophysics Data System (ADS)

    Semertzidis, Yannis; Storage Ring Proton EDM Collaboration

    2014-09-01

    The storage ring pEDM experiment utilizes an all-electric storage ring to store ~1011 longitudinally polarized protons simultaneously in clock-wise and counter-clock-wise directions for 103 seconds. The radial E-field acts on the proton EDM for the duration of the storage time to precess its spin in the vertical plane. The ring lattice is optimized to reduce intra-beam scattering, increase the statistical sensitivity and reduce the systematic errors of the method. The main systematic error is a net radial B-field integrated around the ring causing an EDM-like vertical spin precession. The counter-rotating beams sense this integrated field and are vertically shifted by an amount, which depends on the strength of the vertical focusing in the ring, thus creating a radial B-field. Modulating the vertical focusing at 10 kHz makes possible the detection of this radial B-field by a SQUID-magnetometer (SQUID-based BPM). For a total number of n SQUID-based BPMs distributed around the ring the effectiveness of the method is limited to the N = n /2 harmonic of the background radial B-field due to the Nyquist sampling theorem limit. This limitation establishes the requirement to reduce the maximum radial B-field to 0.1-1 nT everywhere around the ring by layers of mu-metal and aluminum vacuum tube. The metho's sensitivity is 10-29 e .cm , more than three orders of magnitude better than the present neutron EDM experimental limit, making it sensitive to SUSY-like new physics mass scale up to 300 TeV.

  9. High-power microwave-induced TM{sub 01} plasma ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schamiloglu, E.; Jordan, R.; Moreland, L.D.

    1996-02-01

    Open-shutter photography was used to capture the air breakdown pattern induced by a TM{sub 01} mode radiated by a high-power backward wave oscillator. The resultant plasma ring was formed in air adjacent to a conical horn antenna fitted with a membrane to keep the experiment under vacuum. This image was digitized and further processed using Khoros 2.0 software to obtain the dimensions of the plasma ring. This information was used in an air breakdown analysis to estimate the radiated power, and agrees within 10% with the power measured using field mapping with an open-ended WR-90 waveguide.

  10. Two year operational experience with the TPS vacuum system

    NASA Astrophysics Data System (ADS)

    Yang, Y. C.; Chan, C. K.; Sheng, I. C.; Huang, I. T.; Y Chung, J.; Liang, C. C.

    2017-07-01

    The Taiwan Photon Source (TPS), a 3-GeV third generation synchrotron light source, was commissioned in 2014 December and is now currently operated in top-up mode at 300mA for users. During the past two years, the machine was completed to meet design goals with among others the installation of superconducting cavities (SRF), the installation of insertion devices (ID) and the correction of vacuum chamber structure downstream from the IDs. The design goal of 500mA beam current was achieved with a total accumulated beam dose of more than 1000Ah, resulting in three orders of magnitude reduction of out-gassing. As the beam current was increased, a few vacuum problems were encountered, including vacuum leaks, unexpected pressure bursts, etc. Vacuum related issues including high pressure events, lessons learned and operational experience will be presented and discussed in this paper.

  11. Effect of electron irradiation in vacuum on FEP-A silicon solar cell covers

    NASA Technical Reports Server (NTRS)

    Marsik, S. J.; Broder, J. D.

    1975-01-01

    Fluorinated ethylene-propylene-A (FEP-A) covers on silicon solar cells were irradiated with 1-MeV electrons, in vacuum, to an accumulated fluence equivalent to approximately 28 years in synchronous orbit. The effect of irradiation on the light transmittance of FEP-A was checked by measuring the short-circuit current of the cells after each dose increment. The results indicate no apparent overall loss in transmission due to irradiation of FEP-A. Filter wheel measurements revealed some darkening of the FEP-A at the blue end of the spectrum. Although no delamination from the cell surface was observed while in vacuum, embrittlement of FEP-A occurred at the accumulated dose.

  12. Vacuum injection of hydrogen micro-sphere beams

    NASA Astrophysics Data System (ADS)

    Trostell, Bertil

    1995-02-01

    The design, construction and operation of a facility producing hydrogen micro-sphere beams in vacuum are summarized. A scheme is utilized, where a liquid hydrogen jet is broken up into droplets, which are injected into vacuum through a capillary at continuum gas flow conditions. In a typical beam, 40 μm diameter micro-spheres, generated at a frequency of 70 kHz, travel at free flight speeds of 60 m/s. The angular divergence of the beam amounts to ±0.04°. The intention is to use the micro-sphere beams as high luminosity internal targets in the WASA experimental station at the CELSIUS cooler storage ring in Uppsala. A time averaged target density profile, having a FWHM and peak density of 3.5 mm and 5 × 10 16 atoms/cm 2, respectively, is obtained 2.5 m downstream of the capillary exit.

  13. One ring or two? Determination of ring number in carotenoids by lycopene epsilon-cyclases.

    PubMed

    Cunningham, F X; Gantt, E

    2001-02-27

    Carotenoids in the photosynthetic membranes of plants typically contain two beta-rings (e.g., beta-carotene and zeaxanthin) or one epsilon- and one beta-ring (e.g., lutein). Carotenoids with two epsilon-rings are uncommon. We reported earlier that the Arabidopsis thaliana lycopene epsilon-cyclase (LCYe) adds one epsilon-ring to the symmetrical linear substrate lycopene, whereas the structurally related lycopene beta-cyclase (LCYb) adds two beta-rings. Here we describe a cDNA encoding LCYe in romaine lettuce (Lactuca sativa var. romaine), one of the few plant species known to accumulate substantial quantities of a carotenoid with two epsilon-rings: lactucaxanthin. The product of the lettuce cDNA, similar in sequence to the Arabidopsis LCYe (77% amino acid identity), efficiently converted lycopene into the bicyclic epsilon-carotene in a heterologous Escherichia coli system. Regions of the lettuce and Arabidopsis epsilon-cyclases involved in the determination of ring number were mapped by analysis of chimeric epsilon-cyclases constructed by using an inverse PCR approach. A single amino acid was found to act as a molecular switch: lettuce LCYe mutant H457L added only one epsilon-ring to lycopene, whereas the complementary Arabidopsis LCYe mutant, L448H, added two epsilon-rings. An R residue in this position also yields a bi-epsilon-cyclase for both the lettuce and Arabidopsis enzymes. Construction and analysis of chimera of related enzymes with differing catalytic activities provide an informative approach that may be of particular utility for studying membrane-associated enzymes that cannot easily be crystallized or modeled to existing crystal structures.

  14. One ring or two? Determination of ring number in carotenoids by lycopene ɛ-cyclases

    PubMed Central

    Cunningham, Francis X.; Gantt, Elisabeth

    2001-01-01

    Carotenoids in the photosynthetic membranes of plants typically contain two β-rings (e.g., β-carotene and zeaxanthin) or one ɛ- and one β-ring (e.g., lutein). Carotenoids with two ɛ-rings are uncommon. We reported earlier that the Arabidopsis thaliana lycopene ɛ-cyclase (LCYe) adds one ɛ-ring to the symmetrical linear substrate lycopene, whereas the structurally related lycopene β-cyclase (LCYb) adds two β-rings. Here we describe a cDNA encoding LCYe in romaine lettuce (Lactuca sativa var. romaine), one of the few plant species known to accumulate substantial quantities of a carotenoid with two ɛ-rings: lactucaxanthin. The product of the lettuce cDNA, similar in sequence to the Arabidopsis LCYe (77% amino acid identity), efficiently converted lycopene into the bicyclic ɛ-carotene in a heterologous Escherichia coli system. Regions of the lettuce and Arabidopsis ɛ-cyclases involved in the determination of ring number were mapped by analysis of chimeric ɛ-cyclases constructed by using an inverse PCR approach. A single amino acid was found to act as a molecular switch: lettuce LCYe mutant H457L added only one ɛ-ring to lycopene, whereas the complementary Arabidopsis LCYe mutant, L448H, added two ɛ-rings. An R residue in this position also yields a bi-ɛ-cyclase for both the lettuce and Arabidopsis enzymes. Construction and analysis of chimera of related enzymes with differing catalytic activities provide an informative approach that may be of particular utility for studying membrane-associated enzymes that cannot easily be crystallized or modeled to existing crystal structures. PMID:11226339

  15. A ceramic radial insulation structure for a relativistic electron beam vacuum diode.

    PubMed

    Xun, Tao; Yang, Hanwu; Zhang, Jiande; Liu, Zhenxiang; Wang, Yong; Zhao, Yansong

    2008-06-01

    For one kind of a high current diode composed of a small disk-type alumina ceramic insulator water/vacuum interface, the insulation structure was designed and experimentally investigated. According to the theories of vacuum flashover and the rules for radial insulators, a "cone-column" anode outline and the cathode shielding rings were adopted. The electrostatic field along the insulator surface was obtained by finite element analysis simulating. By adjusting the outline of the anode and reshaping the shielding rings, the electric fields were well distributed and the field around the cathode triple junction was effectively controlled. Area weighted statistical method was applied to estimate the surface breakdown field. In addition, the operating process of an accelerator based on a spiral pulse forming line (PFL) was simulated through the PSPICE software to get the waveform of charging and diode voltage. The high voltage test was carried out on a water dielectric spiral PFL accelerator with long pulse duration, and results show that the diode can work stably in 420 kV, 200 ns conditions. The experimental results agree with the theoretical and simulated results.

  16. Wafer-level vacuum/hermetic packaging technologies for MEMS

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hyun; Mitchell, Jay; Welch, Warren; Lee, Sangwoo; Najafi, Khalil

    2010-02-01

    An overview of wafer-level packaging technologies developed at the University of Michigan is presented. Two sets of packaging technologies are discussed: (i) a low temperature wafer-level packaging processes for vacuum/hermeticity sealing, and (ii) an environmentally resistant packaging (ERP) technology for thermal and mechanical control as well as vacuum packaging. The low temperature wafer-level encapsulation processes are implemented using solder bond rings which are first patterned on a cap wafer and then mated with a device wafer in order to encircle and encapsulate the device at temperatures ranging from 200 to 390 °C. Vacuum levels below 10 mTorr were achieved with yields in an optimized process of better than 90%. Pressures were monitored for more than 4 years yielding important information on reliability and process control. The ERP adopts an environment isolation platform in the packaging substrate. The isolation platform is designed to provide low power oven-control, vibration isolation and shock protection. It involves batch flip-chip assembly of a MEMS device onto the isolation platform wafer. The MEMS device and isolation structure are encapsulated at the wafer-level by another substrate with vertical feedthroughs for vacuum/hermetic sealing and electrical signal connections. This technology was developed for high performance gyroscopes, but can be applied to any type of MEMS device.

  17. Coaxial twin-shaft magnetic fluid seals applied in vacuum wafer-handling robot

    NASA Astrophysics Data System (ADS)

    Cong, Ming; Wen, Haiying; Du, Yu; Dai, Penglei

    2012-07-01

    Compared with traditional mechanical seals, magnetic fluid seals have unique characters of high airtightness, minimal friction torque requirements, pollution-free and long life-span, widely used in vacuum robots. With the rapid development of Integrate Circuit (IC), there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment. The parameters of magnetic fluid seals structure is very important in the vacuum robot design. This paper gives a magnetic fluid seal device for the robot. Firstly, the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics, which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal. Secondly, the magnetic analysis model of twin-shaft magnetic fluid seals structure is established. By analyzing the magnetic field distribution of dual magnetic fluid seal, the optimal value ranges of important parameters, including parameters of the permanent magnetic ring, the magnetic pole tooth, the outer shaft, the outer shaft sleeve and the axial relative position of two permanent magnetic rings, which affect the seal differential pressure, are obtained. A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built. Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min, the maximum burst pressure is about 0.24 MPa. Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot. The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.

  18. Broadband impedance calculations and single bunch instabilities estimations of of the HLS-II storage ring

    NASA Astrophysics Data System (ADS)

    Zhang, Qing-Kun; Wang, Lin; Li, Wei-Min; Gao, Wei-Wei

    2015-12-01

    The upgrade project of the Hefei Light Source storage ring is under way. In this paper, the broadband impedances of resistive wall and coated ceramic vacuum chamber are calculated using the analytic formula, and the wake fields and impedances of other designed vacuum chambers are simulated by CST code, and then a broadband impedance model is obtained. Using the theoretical formula, longitudinal and transverse single bunch instabilities are discussed. With the carefully-designed vacuum chamber, we find that the thresholds of the beam instabilities are higher than the beam current goal. Supported by Natural Science Foundation of China (11175182, 11175180)

  19. Design study of the storage ring EUTERPE

    NASA Astrophysics Data System (ADS)

    Xi, Boling; Botman, J. I. M.; Timmermans, C. J.; Hagedoorn, H. L.

    1992-05-01

    At present the 400 MeV electron storage ring EUTERPE is being constructed at the Eindhoven University of Technology. It is a university project set up for studies of charged particle beam dynamics and applications of synchroton radiation, and for the education of students in these fields. The design of the ring is described in this paper. Considering the requirements of users in different fields, a lattice based on a so-called triple bend achromat structure with a high flexibility has been chosen. With this lattice, different optical options, including the HBSB (high brightness, small beam), the SBL (short bunch length) and the HLF (high light flux) modes can be realized. A small emittance of 7 nm rad and a short bunch length of the order of several mm can be achieved. In the first phase the synchrotron radiation in the UV and XUV region (the critical wavelength is 8.3 nm) will be provided from the regular dipole magnets. Later on, a 10 T wiggler magnet and other special inserters will be added, and other applications and beam dynamics studies will be feasible. Bending magnets are of the parallel faced C configuration. The effective aperture of the vacuum chamber is 2.3 cm (vertical) in the bending magnets and 4.7 cm elsewhere with a working vacuum condition of 10-9 Torr. Collective effects have been studied initially. First calculations indicate that a lifetime of several hours, influenced by the Touschek effect and residual gas scattering will be achievable for a 200 mA beam in the HLF mode for the standard rf parameters. A 70 MeV racetrack microtron will serve as injector for the ring.

  20. Experimental characterization of elastomeric O-rings as reusable seals for mass spectrometric measurements: Application to in situ K-Ar dating on Mars

    NASA Astrophysics Data System (ADS)

    Cho, Yuichiro; Kameda, Shingo; Okuno, Mamoru; Horiuchi, Misa; Shibasaki, Kazuo; Wagatsuma, Ryo; Aida, Yusuke; Miura, Yayoi N.; Yoshioka, Kazuo; Okazaki, Ryuji; Sugita, Seiji

    2017-10-01

    Mass spectrometry has been widely used in lander missions to characterize the volatiles in rocks and soils on planetary surfaces. A good vacuum seal is very important for introducing such solid samples to a vacuum chamber and ejecting them. However, multiple measurements require many metal gaskets, leading to extra weight and complexity for the instruments. In this study, we investigate the capability of three kinds of elastomeric O-rings (Viton, Nexus-SLT, and Nexus-FV) as vacuum seals for mass spectrometric measurements, particularly for in situ K-Ar dating on Mars. First, thermal cycle tests revealed that low-temperature-resistant O-rings can maintain pressure <10-5 Pa at -60 °C under 1 bar ambient pressure, whereas Viton O-rings leaked at -25 °C. Then, the amount of 40Ar due to outgassing from the O-rings and permeation under the ambient pressure of 650 Pa or 3 Pa was measured and compared with the amounts of 40Ar that a flight-equivalent laser would liberate from potential target Martian rocks. The measured amounts were <1% of that a target rock with 5000 ppm K2O and an age of 4.2 Ga would yield. These results suggest that a Viton O-ring can maintain the Ar blank low under the Mars atmospheric pressure when temperatures are higher than -25 °C. A double O-ring seal using the low-temperature-resistant elastomers would be an alternative approach at lower temperatures. The elastomeric O-rings would be useful for constructing a small and light-weighted mass spectrometric instrument for in situ K-Ar dating on Mars.

  1. Liesegang Rings in Xanthogranulomatous Pyelonephritis: A Case Report

    PubMed Central

    Pegas, Karla Laís; Edelweiss, Maria Isabel; Cambruzzi, Eduardo; Zettler, Cláudio Galleano

    2010-01-01

    Liesegang rings are concentric noncellular lamellar structures, rarely seen in vivo, occurring as a consequence of the accumulation of insoluble products in a colloidal matrix. These characteristic structures are a rare phenomenon usually found in association with cystic or inflammatory lesions and may be mistaken for parasites. The authors examined Liesegang rings from an inflammatory kidney lesion identified previously as a tumoral lesion on computerized tomography. On microscopic evaluation, Liesegang rings can be mistaken for eggs and larvae of parasites, psammoma bodies and calcification. Special stains like PAS, Grocott, von Kossa and Masson's trichrome facilitate the diagnosis. PMID:21151725

  2. Vacuum force

    NASA Astrophysics Data System (ADS)

    Han, Yongquan

    2015-03-01

    To study on vacuum force, we must clear what is vacuum, vacuum is a space do not have any air and also ray. There is not exist an absolute the vacuum of space. The vacuum of space is relative, so that the vacuum force is relative. There is a certain that vacuum vacuum space exists. In fact, the vacuum space is relative, if the two spaces compared to the existence of relative vacuum, there must exist a vacuum force, and the direction of the vacuum force point to the vacuum region. Any object rotates and radiates. Rotate bend radiate- centripetal, gravity produced, relative gravity; non gravity is the vacuum force. Gravity is centripetal, is a trend that the objects who attracted wants to Centripetal, or have been do Centripetal movement. Any object moves, so gravity makes the object curve movement, that is to say, the radiation range curve movement must be in the gravitational objects, gravity must be existed in non vacuum region, and make the object who is in the region of do curve movement (for example: The earth moves around the sun), or final attracted in the form gravitational objects, and keep relatively static with attract object. (for example: objects on the earth moves but can't reach the first cosmic speed).

  3. High resolution monochromator for the VUV radiation from the DORIS storage ring

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saile, V.; Gurtler, P.; Koch, E.E.

    1976-10-01

    The unique properties of the DORIS storage ring at DESY as a synchroton radiation source are exploited for high resolution spectroscopy in the vacuum ultraviolet. We describe a new experimental set up with a 3-m normal incidence monochromator for wavelengths between 3000 A and 300 A (4 < or = h..omega.. < or = 40 eV) using a vertical dispersion plane. The storage ring provides a light flux intense and stable enough for rapid photoelectrical scanning of the spectra with a resolution of 0.03 A in first order. (AIP)

  4. Measurement of the setting expansion of phosphate-bonded investment materials: Part I - Development of the Casting-Ring Test.

    PubMed

    Lloyd, C H; Yearn, J A; Cowper, G A; Blavier, J; Vanderdonckt, M

    2004-07-01

    The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the 'Casting-Ring Test', the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation.

  5. Relation of Nickel Concentrations in Tree Rings to Groundwater Contamination

    NASA Astrophysics Data System (ADS)

    Yanosky, Thomas M.; Vroblesky, Don A.

    1992-08-01

    Increment cores were collected from trees growing at two sites where groundwater is contaminated by nickel. Proton-induced X ray emission spectroscopy was used to determine the nickel concentrations in selected individual rings and in parts of individual rings. Ring nickel concentrations were interpreted on the basis of recent concentrations of nickel in aquifers, historical information about site use activities, and model simulations of groundwater flow. Nickel concentrations in rings increased during years of site use but not in trees outside the contaminated aquifers. Consequently, it was concluded that trees may preserve in their rings an annual record of nickel contamination in groundwater. Tulip trees and oaks contained higher concentrations of nickel than did sassafras, sweet gum, or black cherry. No evidence was found that nickel accumulates consistently within parts of individual rings or that nickel is translocated across ring boundaries.

  6. Relation of nickel concentrations in tree rings to groundwater contamination

    USGS Publications Warehouse

    Yanosky, Thomas M.; Vroblesky, Don A.

    1992-01-01

    Increment cores were collected from trees growing at two sites where groundwater is contaminated by nickel. Proton-induced X ray emission spectroscopy was used to determine the nickel concentrations in selected individual rings and in parts of individual rings. Ring nickel concentrations were interpreted on the basis of recent concentrations of nickel in aquifers, historical information about site use activities, and model simulations of groundwater flow. Nickel concentrations in rings increased during years of site use but not in trees outside the contaminated aquifers. Consequently, it was concluded that trees may preserve in their rings an annual record of nickel contamination in groundwater. Tulip trees and oaks contained higher concentrations of nickel than did sassafras, sweet gum, or black cherry. No evidence was found that nickel accumulates consistently within parts of individual rings or that nickel is translocated across ring boundaries.

  7. Effect of vacuum roasting on acrylamide formation and reduction in coffee beans.

    PubMed

    Anese, Monica; Nicoli, Maria Cristina; Verardo, Giancarlo; Munari, Marina; Mirolo, Giorgio; Bortolomeazzi, Renzo

    2014-02-15

    Coffea arabica beans were roasted in an oven at 200 °C for increasing lengths of time under vacuum (i.e. 0.15 kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10 min followed by vacuum treatment (0.15 kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Critically safe vacuum pickup for use in wet or dry cleanup of radioactive materials

    DOEpatents

    Zeren, Joseph D.

    1994-01-01

    A vacuum pickup of critically safe quantity and geometric shape is used in cleanup of radioactive materials. Collected radioactive material is accumulated in four vertical, parallel, equally spaced canisters arranged in a cylinder configuration. Each canister contains a filter bag. An upper intake manifold includes four 90 degree spaced, downward facing nipples. Each nipple communicates with the top of a canister. The bottom of each canister communicates with an exhaust manifold comprising four radially extending tubes that meet at the bottom of a centrally located vertical cylinder. The top of the central cylinder terminates at a motor/fan power head. A removable HEPA filter is located intermediate the top of the central cylinder and the power head. Four horizontal bypass tubes connect the top of the central cylinder to the top of each of the canisters. Air enters the vacuum cleaner via a hose connected to the intake manifold. Air then travels down the canisters, where particulate material is accumulated in generally equal quantities in each filter bag. Four air paths of bag filtered air then pass radially inward to the bottom of the central cylinder. Air moves up the central cylinder, through the HEPA filter, through a vacuum fan compartment, and exits the vacuum cleaner. A float air flow valve is mounted at the top of the central cylinder. When liquid accumulates to a given level within the central cylinder, the four bypass tubes, and the four canisters, suction is terminated by operation of the float valve.

  9. Product suitability of wood...determined by density gradients across growth rings

    Treesearch

    Robert M. Echols

    1972-01-01

    The suitability of wood for various uses can be determined by synthesizing single growth-ring density curves from accumulated means of wood density classes. Wood density gradients across growth rings were measured in large increment cores from 46-year-old ponderosa pines (Pinus ponderosa Laws.) by using X-rays. Of the 48 trees analyzed, 36 had been...

  10. In-Vacuum Photogrammetry of a 10-Meter Solar Sail

    NASA Technical Reports Server (NTRS)

    Meyer, Chris G.; Jones, Thomas W.; Lunsford, Charles B.; Pappa, Richard S.

    2005-01-01

    In July 2004, a 10-meter solar sail structure developed by L Garde, Inc. was tested in vacuum at the NASA Glenn 30-meter Plum Brook Space Power Facility in Sandusky, Ohio. The three main objections of the test were to demonstrate unattended deployment from a stowed configuration, to measure the deployed shape of the sail at both ambient and cryogenic room temperatures, and to measure the deployed structural dynamic characteristics (vibration modes). This paper summarizes the work conducted to fulfill the second test objective. The deployed shape was measured photogrammetrically in vacuum conditions with four 2-megapixel digital video cameras contained in custom made pressurized canisters. The canisters included high-intensity LED ring lights to illuminate a grid of retroreflective targets distributed on the solar sail. The test results closely matched pre-test photogrammetry numerical simulations and compare well with ABAQUS finite-element model predictions.

  11. Beam Loss Measurements at the Los Alamos Proton Storage Ring

    NASA Astrophysics Data System (ADS)

    Spickermann, Thomas

    2005-06-01

    During normal operation the Los Alamos Proton Storage Ring (PSR) accumulates up to 4ṡ1013 protons over 625μs with a repetition rate of 20 Hz, corresponding to a current of 125μA to the Lujan Neutron Science Center. Beam losses in the ring as well as in the extraction beam line and the subsequent activation of material are a limiting factor at these currents. Careful tuning of injection, ring and extraction line is paramount to limiting losses to acceptable levels. Losses are typically not uniform around the ring, but occur in significantly higher levels in certain "hot spots". Here I will report on losses related to the stripper foil which are the dominant source of losses in the ring. First results of a comparison with simulations will also be presented.

  12. Irradiation and measurements of fluorinated ethylene-propylene-A on silicon solar cells in vacuum

    NASA Technical Reports Server (NTRS)

    Marsik, S. J.; Broder, J. D.

    1975-01-01

    Silicon monoxide (SiO) coated silicon solar cells covered with fluorinated ethylene-propylene-A (FEP-A) were irradiated by 1-MeV electrons in vacuum. The effect of irradiation on the light transmittance of FEP-A was checked by measuring the short-circuit current of the cells while in vacuum after each dose increment, immediately after the irradiation, and again after a minimum elapsed time of 16 hr. The results indicated no apparent loss in transmission due to irradiation of FEP-A and no delamination from the SiO surface while the cells were in vacuum, but embrittlement of FEP-A occurred at the accumulated dose.

  13. Over-injection and self-oscillations in an electron vacuum diode

    NASA Astrophysics Data System (ADS)

    Leopold, J. G.; Siman-Tov, M.; Goldman, A.; Krasik, Ya. E.

    2017-07-01

    We demonstrate a practical means by which one can inject more than the space-charge limiting current into a vacuum diode. This over-injection causes self-oscillations of the space-charge resulting in an electron beam current modulation at a fixed frequency, a reaction of the system to the Coulomb repulsive forces due to charge accumulation.

  14. Indian Vacuum Society: The Indian Vacuum Society

    NASA Astrophysics Data System (ADS)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  15. Negative plant soil feedback explaining ring formation in clonal plants.

    PubMed

    Cartenì, Fabrizio; Marasco, Addolorata; Bonanomi, Giuliano; Mazzoleni, Stefano; Rietkerk, Max; Giannino, Francesco

    2012-11-21

    Ring shaped patches of clonal plants have been reported in different environments, but the mechanisms underlying such pattern formation are still poorly explained. Water depletion in the inner tussocks zone has been proposed as a possible cause, although ring patterns have been also observed in ecosystems without limiting water conditions. In this work, a spatially explicit model is presented in order to investigate the role of negative plant-soil feedback as an additional explanation for ring formation. The model describes the dynamics of the plant biomass in the presence of toxicity produced by the decomposition of accumulated litter in the soil. Our model qualitatively reproduces the emergence of ring patterns of a single clonal plant species during colonisation of a bare substrate. The model admits two homogeneous stationary solutions representing bare soil and uniform vegetation cover which depend only on the ratio between the biomass death and growth rates. Moreover, differently from other plant spatial patterns models, but in agreement with real field observations of vegetation dynamics, we demonstrated that the pattern dynamics always lead to spatially homogeneous vegetation covers without creation of stable Turing patterns. Analytical results show that ring formation is a function of two main components, the plant specific susceptibility to toxic compounds released in the soil by the accumulated litter and the decay rate of these same compounds, depending on environmental conditions. These components act at the same time and their respective intensities can give rise to the different ring structures observed in nature, ranging from slight reductions of biomass in patch centres, to the appearance of marked rings with bare inner zones, as well as the occurrence of ephemeral waves of plant cover. Our results highlight the potential role of plant-soil negative feedback depending on decomposition processes for the development of transient vegetation patterns

  16. Turning the LHC ring into a new physics search machine

    NASA Astrophysics Data System (ADS)

    Orava, Risto

    2017-03-01

    The LHC Collider Ring is proposed to be turned into an ultimate automatic search engine for new physics in four consecutive phases: (1) Searches for heavy particles produced in Central Exclusive Process (CEP): pp → p + X + p based on the existing Beam Loss Monitoring (BLM) system of the LHC; (2) Feasibility study of using the LHC Ring as a gravitation wave antenna; (3) Extensions to the current BLM system to facilitate precise registration of the selected CEP proton exit points from the LHC beam vacuum chamber; (4) Integration of the BLM based event tagging system together with the trigger/data acquisition systems of the LHC experiments to facilitate an on-line automatic search machine for the physics of tomorrow.

  17. A vacuum-operated pore-water extractor for estuarine and freshwater sediments

    USGS Publications Warehouse

    Winger, Parley V.; Lasier, Peter J.

    1991-01-01

    A vacuum-operated pore-water extractor for estuarine and freshwater sediments was developed and constructed from a fused-glass air stone attached with aquarium airline tubing to a 30 or 60 cc polypropylene syringe. Pore water is extracted by inserting the air stone into the sediment and creating a vacuum by retracting and bracing the syringe plunger. A hand-operated vacuum pump attached to a filtration flask was also evaluated as an alternative vacuum source. The volume and time to extract pore water varies with the number of devices and the sediment particle size. Extraction time is longer for fine sediments than for sandy sediments. Four liters of sediment generally yield between 500 and 1,500 mL of pore water. The sediment that surrounds and accumulates on the air stone acts as a filter, and, except for the first few milliliters, the collected pore water is clear. Because there is no exposure to air or avenue for escape, volatile compounds andin situ characteristics are retained in the extracted pore water.

  18. Pressure distribution along the AGS vacuum chambers with new types of pump out conduits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nayak, S.; Mapes, M.; Smart, L.

    2015-10-28

    The AGS HEBT and ring vacuum system is monitored by the discharge current of the magnet ion pumps, which is proportional to the pressure at the inlet port of these ion pumps. The discharge current is measured and suitably calibrated to indicate the ion pump pressure. In order to calculate the vacuum chamber pressure from the ion pump pressure, a detailed analysis is essential to compute their difference in different scenarios. Such analysis has been carried out numerically in the past for the system with the older type of pump out conduits, and similar analysis using FEM in ANSYS ismore » presented in this paper with the newer type of pump out conduit.« less

  19. Ring structure of a neutral gas cloud studied in a one-dimensional expansion into space

    NASA Technical Reports Server (NTRS)

    Davidson, R. E.

    1972-01-01

    A one dimensional treatment of the expansion of a gas cloud of uncharged particles into vacuum is discussed. It is determined that the whole cloud does not change from continuum to free molecular flow at the same time. Some regions of the cloud make the transition sooner than others. An explanation of the ring structure observed during barium cloud experiments is presented using this conclusion. An analysis of the velocity distributions for the two kinds of flow yields a velocity distribution for the whole cloud that exhibits ring structure.

  20. Improved Blackbody Temperature Sensors for a Vacuum Furnace

    NASA Technical Reports Server (NTRS)

    Farmer, Jeff; Coppens, Chris; O'Dell, J. Scott; McKechnie, Timothy N.; Schofield, Elizabeth

    2009-01-01

    Some improvements have been made in the design and fabrication of blackbody sensors (BBSs) used to measure the temperature of a heater core in a vacuum furnace. Each BBS consists of a ring of thermally conductive, high-melting-temperature material with two tantalum-sheathed thermocouples attached at diametrically opposite points. The name "blackbody sensor" reflects the basic principle of operation. Heat is transferred between the ring and the furnace heater core primarily by blackbody radiation, heat is conducted through the ring to the thermocouples, and the temperature of the ring (and, hence, the temperature of the heater core) is measured by use of the thermocouples. Two main requirements have guided the development of these BBSs: (1) The rings should have as high an emissivity as possible in order to maximize the heat-transfer rate and thereby maximize temperature-monitoring performance and (2) the thermocouples must be joined to the rings in such a way as to ensure long-term, reliable intimate thermal contact. The problem of fabricating a BBS to satisfy these requirements is complicated by an application-specific prohibition against overheating and thereby damaging nearby instrumentation leads through the use of conventional furnace brazing or any other technique that involves heating the entire BBS and its surroundings. The problem is further complicated by another application-specific prohibition against damaging the thin tantalum thermocouple sheaths through the use of conventional welding to join the thermocouples to the ring. The first BBS rings were made of graphite. The tantalum-sheathed thermocouples were attached to the graphite rings by use of high-temperature graphite cements. The ring/thermocouple bonds thus formed were found to be weak and unreliable, and so graphite rings and graphite cements were abandoned. Now, each BBS ring is made from one of two materials: either tantalum or a molybdenum/titanium/zirconium alloy. The tantalum

  1. The Potential-Well Distortion Effect and Coherent Instabilities of Electron Bunches in Storage Rings

    NASA Astrophysics Data System (ADS)

    Korchuganov, V. N.; Smygacheva, A. S.; Fomin, E. A.

    2018-05-01

    The effect of electromagnetic interaction between electron bunches and the vacuum chamber of a storage ring on the longitudinal motion of bunches is studied. Specifically, the potential-well distortion effect and the so-called coherent instabilities of coupled bunches are considered. An approximate analytical solution for the frequencies of incoherent oscillations of bunches distributed arbitrarily within the ring is obtained for a distorted potential well. A new approach to determining frequencies of coherent oscillations and an approximate analytical relation for estimating the stability of a system of bunches as a function of their distribution in the accelerator orbit are presented.

  2. Vacuum Surface Flashover Characteristics and Secondary Electron Emission Characteristics of Epoxy Resin and FRP Insulator

    NASA Astrophysics Data System (ADS)

    Yamano, Yasushi; Takahashi, Masahiro; Kobayashi, Shinichi; Hanada, Masaya; Ikeda, Yoshitaka

    Neutral beam injectors (NBI) used for JT-60 are required to generate negative ions of 500 keV energies. To produce such high-energy ions, the electrostatic accelerators consisting of 3-stage of electrodes and three insulator rings are applied. The insulators are made of Fiberglass Reinforced Plastic (FRP) which is composed of epoxy resin and glass fibers. The surface discharges along the insulators are one of the most serious problems in the development of NBI. To increase the hold-off voltage against surface flashover events, it is necessary to investigate the FRP and epoxy resin insulator properties related to surface discharges in vacuum. This paper describes surface flashover characteristics for epoxy resin, FRP and Alumina samples under vacuum condition. In addition, the measurements of secondary electron emission (SEE) characteristics are also reported. These are important parameters to analyze surface discharge characteristics of insulators in vacuum.

  3. The accumulation pattern of ferruginol in the heartwood-forming Cryptomeria japonica xylem as determined by time-of-flight secondary ion mass spectrometry and quantity analysis

    PubMed Central

    Kuroda, Katsushi; Fujiwara, Takeshi; Hashida, Koh; Imai, Takanori; Kushi, Masayoshi; Saito, Kaori; Fukushima, Kazuhiko

    2014-01-01

    Background and Aims Heartwood formation is a unique phenomenon of tree species. Although the accumulation of heartwood substances is a well-known feature of the process, the accumulation mechanism remains unclear. The aim of this study was to determine the accumulation process of ferruginol, a predominant heartwood substance of Cryptomeria japonica, in heartwood-forming xylem. Methods The radial accumulation pattern of ferruginol was examined from sapwood and through the intermediate wood to the heartwood by direct mapping using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The data were compared with quantitative results obtained from a novel method of gas chromatography analysis using laser microdissection sampling and with water distribution obtained from cryo-scanning electron microscopy. Key Results Ferruginol initially accumulated in the middle of the intermediate wood, in the earlywood near the annual ring boundary. It accumulated throughout the entire earlywood in the inner intermediate wood, and in both the earlywood and the latewood in the heartwood. The process of ferruginol accumulation continued for more than eight annual rings. Ferruginol concentration peaked at the border between the intermediate wood and heartwood, while the concentration was less in the latewood compared wiht the earlywood in each annual ring. Ferruginol tended to accumulate around the ray parenchyma cells. In addition, at the border between the intermediate wood and heartwood, the accumulation was higher in areas without water than in areas with water. Conclusions TOF-SIMS clearly revealed ferruginol distribution at the cellular level. Ferruginol accumulation begins in the middle of intermediate wood, initially in the earlywood near the annual ring boundary, then throughout the entire earlywood, and finally across to the whole annual ring in the heartwood. The heterogeneous timing of ferruginol accumulation could be related to the distribution of ray parenchyma cells

  4. Vacuum mechatronics

    NASA Technical Reports Server (NTRS)

    Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

    1989-01-01

    The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

  5. Expanding Actin Rings Zipper the Mouse Embryo for Blastocyst Formation.

    PubMed

    Zenker, Jennifer; White, Melanie D; Gasnier, Maxime; Alvarez, Yanina D; Lim, Hui Yi Grace; Bissiere, Stephanie; Biro, Maté; Plachta, Nicolas

    2018-04-19

    Transformation from morula to blastocyst is a defining event of preimplantation embryo development. During this transition, the embryo must establish a paracellular permeability barrier to enable expansion of the blastocyst cavity. Here, using live imaging of mouse embryos, we reveal an actin-zippering mechanism driving this embryo sealing. Preceding blastocyst stage, a cortical F-actin ring assembles at the apical pole of the embryo's outer cells. The ring structure forms when cortical actin flows encounter a network of polar microtubules that exclude F-actin. Unlike stereotypical actin rings, the actin rings of the mouse embryo are not contractile, but instead, they expand to the cell-cell junctions. Here, they couple to the junctions by recruiting and stabilizing adherens and tight junction components. Coupling of the actin rings triggers localized myosin II accumulation, and it initiates a tension-dependent zippering mechanism along the junctions that is required to seal the embryo for blastocyst formation. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. The application of vacuum redistillation of patchouli oil to improve patchouli alcohol compound

    NASA Astrophysics Data System (ADS)

    Asnawi, T. M.; Alam, P. N.; Husin, H.; Zaki, M.

    2018-04-01

    Patchouli oil produced by traditional distillation of patchouli leaves and stems by farmers in Aceh still has low patchouli alcohol compound. In order to increase patchouli alcohol concentration, vacuum redistillation process using packed column was introduced. This research was conducted to fractionate terpene (alpha-copinene) from oxygenated hydrocarbon (patchouli alcohol) compound. The operation condition was conducted at two variables that was dependent variable and independent variable. The dependent variable was the 30 cm height distillation packed column, by using raschig ring with 8 mm x 8 mm dimension. And the independent variable was operating temperature 130 °C and 140 °C., vacuum pressure 143,61 mbar, 121,60 mbar and 88,59 mbar and operation time 2 hours, 3 hours and 5 hours. Total of treatments applied in this works were 3 x 3 x 3 or equal to 27 treatments. Patchouli oil used in this research was obtained from Desa Teladan-Lembah Seulawah, Aceh Province. The initial patchouli alcohol compound which analyzed with GC-MS contained 16,02% before treatment applied. After vacuum redistillation process treatment applied patchouli oil concentration increase up to 34,67%. Physico-chemical test of patchouli oil after vacuum redistillation is in accordance with SNI 06-23852006 standard.

  7. Natural vacuum electronics

    NASA Technical Reports Server (NTRS)

    Leggett, Nickolaus

    1990-01-01

    The ambient natural vacuum of space is proposed as a basis for electron valves. Each valve is an electron controlling structure similiar to a vacuum tube that is operated without a vacuum sustaining envelope. The natural vacuum electron valves discussed offer a viable substitute for solid state devices. The natural vacuum valve is highly resistant to ionizing radiation, system generated electromagnetic pulse, current transients, and direct exposure to space conditions.

  8. Motor actuated vacuum door. [for photography from sounding rockets

    NASA Technical Reports Server (NTRS)

    Hanagud, A. V.

    1986-01-01

    Doors that allow scientific instruments to record and retrieve the observed data are often required to be designed and installed as a part of sounding rocket hardware. The motor-actuated vacuum door was designed to maintain a medium vacuum of the order of 0.0001 torr or better while closed, and to provide an opening 15 inches long x 8.5 inches wide while open for cameras to image Halley's comet. When the electric motor receives the instruction to open the door through the payload battery, timer, and relay circuit, the first operation is to unlock the door. After unlatching, the torque transmitted by the motor to the main shaft through the links opens the door. A microswitch actuator, which rides on the linear motion conversion mechanism, is adjusted to trip the limit switch at the end of the travel. The process is repeated in the reverse order to close the door. 'O' rings are designed to maintain the seal. Door mechanisms similar to the one described have flown on Aerobee 17.018 and Black Brant 27.047 payloads.

  9. Effects of vigorous mixing of blood vacuum tubes on laboratory test results.

    PubMed

    Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Gelati, Matteo; Volanski, Waldemar; Boritiza, Katia Cristina; Picheth, Geraldo; Guidi, Gian Cesare

    2013-02-01

    To evaluate the effect of tubes mixing (gentle vs. vigorous) on diagnostic blood specimens collected in vacuum tube systems by venipuncture. Blood was collected for routine coagulation, immunochemistry and hematological testing from one hundred volunteers into six vacuum tubes: two 3.6 mL vacuum tubes containing 0.4 mL of buffered sodium citrate (9NC) 0.109 mol/L: 3.2 W/V%; two 3.5 mL vacuum tubes with clot activator and gel separator; and two 3.0 mL vacuum tubes containing 5.9 mg K(2)EDTA (Terumo Europe, Belgium). Immediately after the venipuncture all vacuum tubes (each of one additive type) were processed through two different procedures: i) Standard: blood specimens in K(2)EDTA- or sodium citrate-vacuum tubes were gently inverted five times whereas the specimens in tubes with clot activator and gel separator were gently inverted ten times, as recommended by the manufacturer; ii) Vigorous mix: all blood specimens were shaken up vigorously during 3-5s independently of the additive type inside the tubes. The significance of the differences between samples was assessed by Student's t-test or Wilcoxon ranked-pairs test after checking for normality. The level of statistical significance was set at P<0.05. No significant difference (P<0.05) was detected between the procedures for all tested parameters. Surprisingly only a visual alteration (presence of foam on the top) was shown by all the tubes mixed vigorously before centrifugation (Fig. 1 A, B and C). Moreover the serum tubes from vigorous mixing procedure shows a "blood ring" on the tube top after stopper removal (Fig. 1 D). Our results drop out a paradigm suggesting that the incorrect primary blood tubes mixing promotes laboratory variability. We suggest that similar evaluation should be done using other brands of vacuum tubes by each laboratory manager. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  10. Hybrid plasmonic waveguide-assisted Metal–Insulator–Metal ring resonator for refractive index sensing

    NASA Astrophysics Data System (ADS)

    Butt, M. A.; Khonina, S. N.; Kazanskiy, N. L.

    2018-05-01

    A highly sensitive refractive index sensor based on an integrated hybrid plasmonic waveguide (HPWG) and a Metal-Insulator-Metal (M-I-M) micro-ring resonator is presented. In our design, there are two slot-waveguide-based micro-rings that encircle a gold disc. The outer slot WG is formed by the combination of Silicon-Air-Gold ring and the inner slot-waveguide is formed by Gold ring-Air-Gold disc. The slot-waveguide rings provide an interaction length sufficient to accumulate a detectable wavelength shift. The transmission spectrum and electric field distribution of this sensor structure are simulated using Finite Element Method (FEM). The sensitivity of this micro-ring resonator is achieved at 800 nm/RIU which is about six times higher than that of the conventional Si ring with the same geometry. Our proposed sensor design has a potential to find further applications in biomedical science and nano-photonic circuits.

  11. Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

    NASA Technical Reports Server (NTRS)

    Golliher, Eric L.; Yao, S. C.

    2015-01-01

    Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

  12. VACUUM TRAP

    DOEpatents

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  13. Layout of the LER (Low Energy Ring) Arc

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hutton, A.

    We have recently been trying to accumulate all of the information necessary to decide on the layout of the regular curved arcs of the Low Energy Ring (LER) and there have been several ABC Notes published on different aspects of the problem. This note will describe the layout that has been derived from these considerations.

  14. NSLS-II storage ring insertion device and front-end commissioning and operation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, G., E-mail: gwang@bnl.gov; Shaftan, T.; Amundsen, C.

    The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. During spring/ summer of 2014, the storage ring was commissioned up to 50 mA without insertion devices. In the fall of 2014, we began commissioning of the project beamlines, which included seven insertion devices on six ID ports. Beamlines IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1 consist of elliptically polarized undulator (EPU), damping wigglers (DW) and in-vacuum undulators (IVU) covering from VUV to hard x-ray range. In this paper, experience with commissioning and operation is discussed.more » We focus on reaching storage ring performance with IDs, including injection, design emittance, compensation of orbit distortions caused by ID residual field, source point stability, beam alignment and tools for control, monitoring and protection of the ring chambers from ID radiation.« less

  15. The thin-wall tube drift chamber operating in vacuum (prototype)

    NASA Astrophysics Data System (ADS)

    Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  16. Nonmedially assembled F-actin cables incorporate into the actomyosin ring in fission yeast

    PubMed Central

    Huang, Junqi; Huang, Yinyi; Yu, Haochen; Subramanian, Dhivya; Padmanabhan, Anup; Thadani, Rahul; Tao, Yaqiong; Tang, Xie; Wedlich-Soldner, Roland

    2012-01-01

    In many eukaryotes, cytokinesis requires the assembly and constriction of an actomyosin-based contractile ring. Despite the central role of this ring in cytokinesis, the mechanism of F-actin assembly and accumulation in the ring is not fully understood. In this paper, we investigate the mechanism of F-actin assembly during cytokinesis in Schizosaccharomyces pombe using lifeact as a probe to monitor actin dynamics. Previous work has shown that F-actin in the actomyosin ring is assembled de novo at the division site. Surprisingly, we find that a significant fraction of F-actin in the ring was recruited from formin-Cdc12p nucleated long actin cables that were generated at multiple nonmedial locations and incorporated into the ring by a combination of myosin II and myosin V activities. Our results, together with findings in animal cells, suggest that de novo F-actin assembly at the division site and directed transport of F-actin cables assembled elsewhere can contribute to ring assembly. PMID:23185032

  17. Jupiter's Main Ring/Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the

  18. The MAX IV storage ring project

    PubMed Central

    Tavares, Pedro F.; Leemann, Simon C.; Sjöström, Magnus; Andersson, Åke

    2014-01-01

    The MAX IV facility, currently under construction in Lund, Sweden, features two electron storage rings operated at 3 GeV and 1.5 GeV and optimized for the hard X-ray and soft X-ray/VUV spectral ranges, respectively. A 3 GeV linear accelerator serves as a full-energy injector into both rings as well as a driver for a short-pulse facility, in which undulators produce X-ray pulses as short as 100 fs. The 3 GeV ring employs a multibend achromat (MBA) lattice to achieve, in a relatively short circumference of 528 m, a bare lattice emittance of 0.33 nm rad, which reduces to 0.2 nm rad as insertion devices are added. The engineering implementation of the MBA lattice raises several technological problems. The large number of strong magnets per achromat calls for a compact design featuring small-gap combined-function magnets grouped into cells and sharing a common iron yoke. The small apertures lead to a low-conductance vacuum chamber design that relies on the chamber itself as a distributed copper absorber for the heat deposited by synchrotron radiation, while non-evaporable getter (NEG) coating provides for reduced photodesorption yields and distributed pumping. Finally, a low main frequency (100 MHz) is chosen for the RF system yielding long bunches, which are further elongated by passively operated third-harmonic Landau cavities, thus alleviating collective effects, both coherent (e.g. resistive wall instabilities) and incoherent (intrabeam scattering). In this paper, we focus on the MAX IV 3 GeV ring and present the lattice design as well as the engineering solutions to the challenges inherent to such a design. As the first realisation of a light source based on the MBA concept, the MAX IV 3 GeV ring offers an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources. PMID:25177978

  19. Development of large volume double ring penning plasma discharge source for efficient light emissions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prakash, Ram; Vyas, Gheesa Lal; Jain, Jalaj

    In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed Penning discharge source consists of two cylindrical end cathodes of stainless steel having radius 6 cm and a gap 5.5 cm between them, which are fitted in the top and bottom flanges of the vacuum chamber. Two stainless steel anode rings with thickness 0.4 cm and inner diameters 6.45 cm having separation 2 cm are kept at the discharge centre. Neodymium (Nd{sub 2}Fe{sub 14}B) permanent magnets are physically inserted behind the cathodes for producing nearly uniform magnetic fieldmore » of {approx}0.1 T at the center. Experiments and simulations have been performed for single and double anode ring configurations using helium gas discharge, which infer that double ring configuration gives better light emissions in the large volume Penning plasma discharge arrangement. The optical emission spectroscopy measurements are used to complement the observations. The spectral line-ratio technique is utilized to determine the electron plasma density. The estimated electron plasma density in double ring plasma configuration is {approx}2 Multiplication-Sign 10{sup 11} cm{sup -3}, which is around one order of magnitude larger than that of single ring arrangement.« less

  20. Development of large volume double ring penning plasma discharge source for efficient light emissions.

    PubMed

    Prakash, Ram; Vyas, Gheesa Lal; Jain, Jalaj; Prajapati, Jitendra; Pal, Udit Narayan; Chowdhuri, Malay Bikas; Manchanda, Ranjana

    2012-12-01

    In this paper, the development of large volume double ring Penning plasma discharge source for efficient light emissions is reported. The developed Penning discharge source consists of two cylindrical end cathodes of stainless steel having radius 6 cm and a gap 5.5 cm between them, which are fitted in the top and bottom flanges of the vacuum chamber. Two stainless steel anode rings with thickness 0.4 cm and inner diameters 6.45 cm having separation 2 cm are kept at the discharge centre. Neodymium (Nd(2)Fe(14)B) permanent magnets are physically inserted behind the cathodes for producing nearly uniform magnetic field of ~0.1 T at the center. Experiments and simulations have been performed for single and double anode ring configurations using helium gas discharge, which infer that double ring configuration gives better light emissions in the large volume Penning plasma discharge arrangement. The optical emission spectroscopy measurements are used to complement the observations. The spectral line-ratio technique is utilized to determine the electron plasma density. The estimated electron plasma density in double ring plasma configuration is ~2 × 10(11) cm(-3), which is around one order of magnitude larger than that of single ring arrangement.

  1. A multi-functional high voltage experiment apparatus for vacuum surface flashover switch research.

    PubMed

    Zeng, Bo; Su, Jian-cang; Cheng, Jie; Wu, Xiao-long; Li, Rui; Zhao, Liang; Fang, Jin-peng; Wang, Li-min

    2015-04-01

    A multifunctional high voltage apparatus for experimental researches on surface flashover switch and high voltage insulation in vacuum has been developed. The apparatus is composed of five parts: pulse generating unit, axial field unit, radial field unit, and two switch units. Microsecond damped ringing pulse with peak-to-peak voltage 800 kV or unipolar pulse with maximum voltage 830 kV is generated, forming transient axial or radial electrical field. Different pulse waveforms and field distributions make up six experimental configurations in all. Based on this apparatus, preliminary experiments on vacuum surface flashover switch with different flashover dielectric materials have been conducted in the axial field unit, and nanosecond pulse is generated in the radial field unit which makes a pulse transmission line in the experiment. Basic work parameters of this kind of switch such as lifetime, breakdown voltage are obtained.

  2. Method and apparatus for performing in-situ vacuum-assisted metal to glass sealing

    DOEpatents

    Kramer, D.P.; Massey, R.T.

    1985-07-18

    A method and apparatus for assembling and fusing glass to metal in a glass-metal electrical component is disclosed. The component includes a metallic shell formed with upper and lower cylindrical recesses connected together by longitudinal passages, a pair of metal rings and plural metal pins assembled to define electrical feed-throughs. The component parts are assembled on a fixture having a sleeve-like projection and a central mounting projection establishing concentric nesting surfaces to which the metal rings are slip-fitted in concentric alignment with each other spaced from sidewalls of the lower recess. The pins are in electrical contact with the metal rings. A glass pre-form is seated within the upper recess. The assembled structure is heated to a temperature sufficient to melt the glass pre-form which flows under gravity through the passages into the lower recess to provide an insulative seal between the metal parts. The gravity flow of glass is assisted by applying vacuum to the lower recess, ensuring that all spaces between the metal parts are filled with sealing glass without formation of bubbles.

  3. Method and apparatus for performing in-situ vacuum-assisted metal to glass sealing

    DOEpatents

    Kramer, Daniel P.; Massey, Richard T.

    1986-01-01

    A method and apparatus for assembling and fusing glass to metal in a glass-metal electrical component is disclosed. The component includes a metallic shell formed with upper and lower cylindrical recesses connected together by longitudinal passages, a pair of metal rings and plural metal pins assembled to define electrical feed-throughs. The component parts are assembled on a fixture having a sleeve-like projection and a central mounting projection establishing concentric nesting surfaces to which the metal rings are slip-fitted in concentric alignment with each other spaced from sidewalls of the lower recess. The pins are in electrical contact with the metal rings. A glass pre-form is seated within the upper recess. The assembled structure is heated to a temperature sufficient to melt the glass pre-form which flows under gravity through the passages into the lower recess to provide an insulative seal between the metal parts. The gravity flow of glass is assisted by applying vacuum to the lower recess, ensuring that all spaces between the metal parts are filled with sealing glass without formation of bubbles.

  4. Comparison of vacuum and non-vacuum urine tubes for urinary sediment analysis.

    PubMed

    Topcuoglu, Canan; Sezer, Sevilay; Kosem, Arzu; Ercan, Mujgan; Turhan, Turan

    2017-12-01

    Urine collection systems with aspiration system for vacuum tubes are becoming increasingly common for urinalysis, especially for microscopic examination of the urine. In this study, we aimed to examine whether vacuum aspiration of the urine sample has any adverse effect on sediment analysis by comparing results from vacuum and non-vacuum urine tubes. The study included totally 213 urine samples obtained from inpatients and outpatients in our hospital. Urine samples were collected to containers with aspiration system for vacuum tubes. Each sample was aliquoted to both vacuum and non-vacuum urine tubes. Urinary sediment analysis was performed using manual microscope. Results were evaluated using chi-square test. Comparison of the sediment analysis results from vacuum and non-vacuum urine tubes showed that results were highly concordant for erythrocyte, leukocyte and epithelial cells (gamma values 1, 0.997, and 0.994, respectively; p < .001). Results were also concordant for urinary casts, crystals and yeast (kappa values 0.815, 0.945 and 1, respectively; p < .001). The results show that in urinary sediment analysis, vacuum aspiration has no adverse effect on the cellular components except on casts.

  5. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry

    2014-03-01

    Preface: a personal view of planetary rings; 1. Introduction: the allure of the ringed planets; 2. Studies of planetary rings 1610-2013; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Uranus' rings and moons; 13. Neptune's partial rings; 14. Jupiter's ring-moon system after Galileo and New Horizons; 15. Ring photometry; 16. Dusty rings; 17. Concluding remarks; Afterword; Glossary; References; Index.

  6. ACCELERATORS: Beam based alignment of the SSRF storage ring

    NASA Astrophysics Data System (ADS)

    Zhang, Man-Zhou; Li, Hao-Hu; Jiang, Bo-Cheng; Liu, Gui-Min; Li, De-Ming

    2009-04-01

    There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.

  7. Saturn's Rings and Associated Ring Plasma Cavity: Evidence for Slow Ring Erosion

    NASA Technical Reports Server (NTRS)

    Farrell, W. M.; Kurth, W. S.; Gurnett, D. A.; Persoon, A. M.; MacDowall, R. J.

    2017-01-01

    We re-examine the radio and plasma wave observations obtained during the Cassini Saturn orbit insertion period, as the spacecraft flew over the northern ring surface into a radial distance of 1.3 Rs (over the C-ring). Voyager era studies suggest the rings are a source of micro-meteoroid generated plasma and dust, with theorized peak impact-created plasma outflows over the densest portion of the rings (central B-ring). In sharp contrast, the Cassini Radio and Plasma Wave System (RPWS) observations identify the presence of a ring-plasma cavity located in the central portion of the B-ring, with little evidence of impact-related plasma. While previous Voyager era studies have predicted unstable ion orbits over the C- ring, leading to field-aligned plasma transport to Saturns ionosphere, the Cassini RPWS observations do not reveal evidence for such instability-created plasma fountains. Given the passive ring loss processes observed by Cassini, we find that the ring lifetimes should extend >10(exp 9) years, and that there is limited evidence for prompt destruction (loss in <100 Myrs).

  8. Saturn's rings and associated ring plasma cavity: Evidence for slow ring erosion

    NASA Astrophysics Data System (ADS)

    Farrell, W. M.; Kurth, W. S.; Gurnett, D. A.; Persoon, A. M.; MacDowall, R. J.

    2017-08-01

    We re-examine the radio and plasma wave observations obtained during the Cassini Saturn orbit insertion period, as the spacecraft flew over the northern ring surface into a radial distance of 1.3 Rs (over the C-ring). Voyager era studies suggest the rings are a source of micro-meteoroid generated plasma and dust, with theorized peak impact-created plasma outflows over the densest portion of the rings (central B-ring). In sharp contrast, the Cassini Radio and Plasma Wave System (RPWS) observations identify the presence of a ring-plasma cavity located in the central portion of the B-ring, with little evidence of impact-related plasma. While previous Voyager era studies have predicted unstable ion orbits over the C-ring, leading to field-aligned plasma transport to Saturn's ionosphere, the Cassini RPWS observations do not reveal evidence for such instability-created plasma 'fountains'. Given the passive ring loss processes observed by Cassini, we find that the ring lifetimes should extend >109 years, and that there is limited evidence for prompt destruction (loss in <100 Myrs).

  9. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems. (a) Vacuum brake assist unit integrity. The vacuum brake assist unit shall demonstrate integrity as... maintained on the pedal. (1) Inspection procedure. Stop the engine and apply service brake several times to...

  10. Demonstrations with a Vacuum: Old Demonstrations for New Vacuum Pumps.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1989-01-01

    Explains mechanisms of 19th-century vacuum pumps. Describes demonstrations using the pump including guinea and feather tube, aurora tube, electric egg, Gassiots cascade, air mill, bell in vacuum, density and buoyancy of air, fountain in vacuum, mercury shower, palm and bladder glasses, Bacchus demonstration, pneumatic man-lifter, and Magdeburg…

  11. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.

    2011-07-01

    Preface; 1. Introduction: the allure of ringed planets; 2. Studies of planetary rings 1610-2004; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-Body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Neptune's partial rings; 13. Jupiter's ring-moon system after Galileo; 14. Ring photometry; 15. Dusty rings; 16. Cassini observations; 17. Summary: the big questions; Glossary; References; Index.

  12. The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname

    PubMed Central

    Neupane, Prem R.

    2017-01-01

    The world’s forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth—periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time. PMID:28813429

  13. The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname.

    PubMed

    Köhl, Michael; Neupane, Prem R; Lotfiomran, Neda

    2017-01-01

    The world's forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth-periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.

  14. Improved Vacuum Bazooka

    NASA Astrophysics Data System (ADS)

    Cockman, John

    2003-04-01

    This apparatus is a modification to the well-known "vacuum bazooka" (PIRA 2B30.70). My vacuum bazooka is easy to construct and demonstrate, requires no precise fittings, foil, or vacuum grease, and propels ping-pong balls at a tremendous velocity!

  15. Very-Low-Cost, Rugged Vacuum System

    NASA Technical Reports Server (NTRS)

    Kline-Schoder, Robert; Sorensen, Paul; Passow, Christian; Bilski, Steve

    2013-01-01

    NASA, DoD, DHS, and commercial industry have a need for miniaturized, rugged, low-cost vacuum systems. Recent advances in sensor technology have led to the development of very small mass spectrometer detectors as well as other miniature analytical instruments. However, the vacuum systems to support these sensors remain large, heavy, and power-hungry. To meet this need, a miniaturized vacuum system was created based on a very small, rugged, and inexpensive- to-manufacture molecular drag pump (MDP). The MDP is enabled by the development of a miniature, veryhigh- speed, rugged, low-power, brushless DC motor optimized for wide temperature operation and long life. Such a pump represents an order-of-magnitude reduction in mass, volume, and cost over current, commercially available, state-ofthe- art vacuum pumps. The vacuum system consists of the MDP coupled to a ruggedized rough pump (for terrestrial applications or for planets with substantial atmospheres). The rotor in the MDP consists of a simple smooth cylinder of aluminum spinning at approximately 200,000 RPM inside an outer stator housing. The pump stator comprises a cylindrical aluminum housing with one or more specially designed grooves that serve as flow channels. To minimize the length of the pump, the gas is forced down the flow channels of the outer stator to the base of the pump. The gas is then turned and pulled toward the top through a second set of channels cut into an inner stator housing that surrounds the motor. The compressed gas then flows down channels in the motor housing to the exhaust port of the pump. The exhaust port of the pump is connected to a diaphragm or scroll pump. This pump delivers very high performance in a very small envelope. The design was simplified so that a smaller compression ratio, easier manufacturing process, and enhanced ruggedness can be achieved at the lowest possible cost. The machining of the rotor and stators is very simple compared to that necessary to fabricate TMP

  16. The Classical Vacuum.

    ERIC Educational Resources Information Center

    Boyer, Timothy H.

    1985-01-01

    The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of…

  17. Electroweak vacuum instability and renormalized Higgs field vacuum fluctuations in the inflationary universe

    NASA Astrophysics Data System (ADS)

    Kohri, Kazunori; Matsui, Hiroki

    2017-08-01

    In this work, we investigated the electroweak vacuum instability during or after inflation. In the inflationary Universe, i.e., de Sitter space, the vacuum field fluctuations < δ phi 2 > enlarge in proportion to the Hubble scale H2. Therefore, the large inflationary vacuum fluctuations of the Higgs field < δ phi 2 > are potentially catastrophic to trigger the vacuum transition to the negative-energy Planck-scale vacuum state and cause an immediate collapse of the Universe. However, the vacuum field fluctuations < δ phi 2 >, i.e., the vacuum expectation values have an ultraviolet divergence, and therefore a renormalization is necessary to estimate the physical effects of the vacuum transition. Thus, in this paper, we revisit the electroweak vacuum instability from the perspective of quantum field theory (QFT) in curved space-time, and discuss the dynamical behavior of the homogeneous Higgs field phi determined by the effective potential V eff( phi ) in curved space-time and the renormalized vacuum fluctuations < δ phi 2 >ren via adiabatic regularization and point-splitting regularization. We simply suppose that the Higgs field only couples the gravity via the non-minimal Higgs-gravity coupling ξ(μ). In this scenario, the electroweak vacuum stability is inevitably threatened by the dynamical behavior of the homogeneous Higgs field phi, or the formations of AdS domains or bubbles unless the Hubble scale is small enough H< ΛI .

  18. Germanium detector vacuum encapsulation

    NASA Technical Reports Server (NTRS)

    Madden, N. W.; Malone, D. F.; Pehl, R. H.; Cork, C. P.; Luke, P. N.; Landis, D. A.; Pollard, M. J.

    1991-01-01

    This paper describes an encapsulation technology that should significantly improve the viability of germanium gamma-ray detectors for a number of important applications. A specialized vacuum chamber has been constructed in which the detector and the encapsulating module are processed in high vacuum. Very high vacuum conductance is achieved within the valveless encapsulating module. The detector module is then sealed without breaking the chamber vacuum. The details of the vacuum chamber, valveless module, processing, and sealing method are presented.

  19. Development of High Interruption Capability Vacuum Circuit Breaker -Technology of Vacuum Arc Control-

    NASA Astrophysics Data System (ADS)

    Niwa, Yoshimitsu; Kaneko, Eiji

    Vacuum circuit breakers (VCB) have been widely used for power distribution systems. Vacuum Interrupters, which are the current interruption unit, have been increased its interruption capability with the development of vacuum arc control technology by magnetic field. There are three major type electrodes: disk shaped electrodes, radial magnetic field electrodes, axial magnetic field (AMF) electrodes. In the disk shaped electrode, the vacuum arc between the electrodes is not controlled. In the AMF electrode, the vacuum arc is diffused and stabilized by an axial magnetic field, which is parallel to the arc current. In the last type of electrodes, the vacuum arc column is rotated by magnetic force generated by the current flowing in the electrodes. The interruption current and the voltage of one break VCB is increased to 100 kA, 144 kV respectively. This paper describes basic configurations and functions of VCB, vacuum arc control technology in vacuum interrupters, recent researches and applications of VCB.

  20. Electroweak vacuum instability and renormalized Higgs field vacuum fluctuations in the inflationary universe

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kohri, Kazunori; Matsui, Hiroki, E-mail: kohri@post.kek.jp, E-mail: matshiro@post.kek.jp

    In this work, we investigated the electroweak vacuum instability during or after inflation. In the inflationary Universe, i.e., de Sitter space, the vacuum field fluctuations < δ φ {sup 2} > enlarge in proportion to the Hubble scale H {sup 2}. Therefore, the large inflationary vacuum fluctuations of the Higgs field < δ φ {sup 2} > are potentially catastrophic to trigger the vacuum transition to the negative-energy Planck-scale vacuum state and cause an immediate collapse of the Universe. However, the vacuum field fluctuations < δ φ {sup 2} >, i.e., the vacuum expectation values have an ultraviolet divergence, andmore » therefore a renormalization is necessary to estimate the physical effects of the vacuum transition. Thus, in this paper, we revisit the electroweak vacuum instability from the perspective of quantum field theory (QFT) in curved space-time, and discuss the dynamical behavior of the homogeneous Higgs field φ determined by the effective potential V {sub eff}( φ ) in curved space-time and the renormalized vacuum fluctuations < δ φ {sup 2} >{sub ren} via adiabatic regularization and point-splitting regularization. We simply suppose that the Higgs field only couples the gravity via the non-minimal Higgs-gravity coupling ξ(μ). In this scenario, the electroweak vacuum stability is inevitably threatened by the dynamical behavior of the homogeneous Higgs field φ, or the formations of AdS domains or bubbles unless the Hubble scale is small enough H < Λ {sub I} .« less

  1. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    NASA Astrophysics Data System (ADS)

    Shin, Joong-Won; Bernstein, Elliot R.

    2014-01-01

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5'-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

  2. Vacuum ultraviolet photoionization of carbohydrates and nucleotides.

    PubMed

    Shin, Joong-Won; Bernstein, Elliot R

    2014-01-28

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5(')-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

  3. Vacuum ultraviolet photoionization of carbohydrates and nucleotides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shin, Joong-Won, E-mail: jshin@govst.edu; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872; Bernstein, Elliot R., E-mail: erb@lamar.colostate.edu

    Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5{sup ′}-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate,more » rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.« less

  4. Report of the eRHIC Ring-Ring Working Group

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aschenauer, E. C.; Berg, S.; Blaskiewicz, M.

    2015-10-13

    This report evaluates the ring-ring option for eRHIC as a lower risk alternative to the linac-ring option. The reduced risk goes along with a reduced initial luminosity performance. However, a luminosity upgrade path is kept open. This upgrade path consists of two branches, with the ultimate upgrade being either a ring-ring or a linac-ring scheme. The linac-ring upgrade could be almost identical to the proposed linac-ring scheme, which is based on an ERL in the RHIC tunnel. This linac-ring version has been studied in great detail over the past ten years, and its significant risks are known. On the othermore » hand, no detailed work on an ultimate performance ring-ring scenario has been performed yet, other than the development of a consistent parameter set. Pursuing the ring-ring upgrade path introduces high risks and requires significant design work that is beyond the scope of this report.« less

  5. Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Cuzzi, J. N.

    2014-12-01

    The rings are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major ring science progress over the mission to date, and describe new observations planned for Cassini's final three years. Ring Composition and particle sizes: The rings are nearly all water ice with no other ices - so why are they reddish? The C Ring and Cassini Division are "dirtier" than the more massive B and A Rings, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. Ring structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main ring divisions, the C Ring plateau structures, and the B Ring irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A ring. Rubble pile ringmoons just outside the rings may escaped from the rings, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the rings: Comet fragments set the rings to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the Rings: The ring mass and bombardment play key roles. The ring mass is well known everywhere but in the B Ring (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient rings, of which the current ring is just a shadow. During its last three years, the Cassini tour profile will allow entirely new

  6. Characterization of an in-vacuum PILATUS 1M detector.

    PubMed

    Wernecke, Jan; Gollwitzer, Christian; Müller, Peter; Krumrey, Michael

    2014-05-01

    A dedicated in-vacuum X-ray detector based on the hybrid pixel PILATUS 1M detector has been installed at the four-crystal monochromator beamline of the PTB at the electron storage ring BESSY II in Berlin, Germany. Owing to its windowless operation, the detector can be used in the entire photon energy range of the beamline from 10 keV down to 1.75 keV for small-angle X-ray scattering (SAXS) experiments and anomalous SAXS at absorption edges of light elements. The radiometric and geometric properties of the detector such as quantum efficiency, pixel pitch and module alignment have been determined with low uncertainties. The first grazing-incidence SAXS results demonstrate the superior resolution in momentum transfer achievable at low photon energies.

  7. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  8. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-03-06

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  9. Oak tree-rings record spatial-temporal pollution trends from different sources in Terni (Central Italy).

    PubMed

    Perone, A; Cocozza, C; Cherubini, P; Bachmann, O; Guillong, M; Lasserre, B; Marchetti, M; Tognetti, R

    2018-02-01

    Monitoring atmospheric pollution in industrial areas near urban center is essential to infer past levels of contamination and to evaluate the impact for environmental health and safety. The main aim of this study was to understand if the chemical composition of tree-ring wood can be used for monitoring spatial-temporal variability of pollutants in Terni, Central Italy, one of the most polluted towns in Italy. Tree cores were taken from 32 downy oaks (Quercus pubescens) located at different distances from several pollutant sources, including a large steel factory. Trace element (Cr, Co, Cu, Pb, Hg, Mo, Ni, Tl, W, U, V, and Zn) index in tree-ring wood was determined using high-resolution laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We hypothesized that the presence of contaminants detected in tree-rings reflected industrial activities over time. The accumulation of contaminants in tree-rings was affected by anthropogenic activities in the period 1958-2009, though signals varied in intensity with the distance of trees from the industrial plant. A stronger limitation of tree growth was observed in the proximity of the industrial plant in comparison with other pollutant sources. Levels of Cr, Ni, Mo, V, U and W increased in tree-ring profiles of trees close to the steel factory, especially during the 80's and 90's, in correspondence to a peak of pollution in this period, as recorded by air quality monitoring stations. Uranium contents in our tree-rings were difficult to explain, while the higher contents of Cu, Hg, Pb, and Tl could be related to the contaminants released from an incinerator located close to the industrial plant. The accumulation of contaminants in tree-rings reflected the historical variation of environmental pollution in the considered urban context. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Future Synchrotron Light Sources Based on Ultimate Storage Rings

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cai, Yunhai; /SLAC

    2012-04-09

    The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving anmore » ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic

  11. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.

    Planetary rings are the only nearby astrophysical disks and the only disks that have been investigated by spacecraft (especially the Cassini spacecraft orbiting Saturn). Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 10- 7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close range and in real time in planetary rings.We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The A, B, and C rings of Saturn, plus the Cassini Division, comprise our solar system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are found both at Uranus (where they comprise the main rings entirely) and at Saturn (where they are embedded in the broad disk) and are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty rings, likely generated by embedded source bodies, are surprisingly found to sport azimuthally confined arcs at Neptune, Saturn, and Jupiter. Finally, every known ring system includes a substantial component of diffuse dusty rings.Planetary rings have shown themselves to be useful as detectors of planetary processes around them, including the planetary magnetic field and interplanetary impactors as well as the gravity of nearby perturbing moons. Experimental rings science has made great progress in recent decades, especially numerical simulations of self-gravity wakes and other processes but also laboratory investigations of coefficient of restitution and spectroscopic ground truth. The age of self-sustained ring systems is a matter of

  12. Vacuum fluctuations in an ancestor vacuum: A possible dark energy candidate

    NASA Astrophysics Data System (ADS)

    Aoki, Hajime; Iso, Satoshi; Lee, Da-Shin; Sekino, Yasuhiro; Yeh, Chen-Pin

    2018-02-01

    We consider an open universe created by bubble nucleation, and study possible effects of our "ancestor vacuum," a de Sitter space in which bubble nucleation occurred, on the present universe. We compute vacuum expectation values of the energy-momentum tensor for a minimally coupled scalar field, carefully taking into account the effect of the ancestor vacuum by the Euclidean prescription. We pay particular attention to the so-called supercurvature mode, a non-normalizable mode on a spatial slice of the open universe, which has been known to exist for sufficiently light fields. This mode decays in time most slowly, and may leave residual effects of the ancestor vacuum, potentially observable in the present universe. We point out that the vacuum energy of the quantum field can be regarded as dark energy if mass of the field is of order the present Hubble parameter or smaller. We obtain preliminary results for the dark energy equation of state w (z ) as a function of the redshift.

  13. Optical extinction efficiency measurements on fine and accumulation mode aerosol using single particle cavity ring-down spectroscopy.

    PubMed

    Cotterell, Michael I; Mason, Bernard J; Preston, Thomas C; Orr-Ewing, Andrew J; Reid, Jonathan P

    2015-06-28

    A new experiment is presented for the measurement of single aerosol particle extinction efficiencies, Qext, combining cavity ring-down spectroscopy (CRDS, λ = 405 nm) with a Bessel beam trap (λ = 532 nm) in tandem with phase function (PF) measurements. This approach allows direct measurements of the changing optical cross sections of individual aerosol particles over indefinite time-frames facilitating some of the most comprehensive measurements of the optical properties of aerosol particles so far made. Using volatile 1,2,6-hexanetriol droplets, Qext is measured over a continuous radius range with the measured Qext envelope well described by fitted cavity standing wave (CSW) Mie simulations. These fits allow the refractive index at 405 nm to be determined. Measurements are also presented of Qext variation with RH for two hygroscopic aqueous inorganic systems ((NH4)2SO4 and NaNO3). For the PF and the CSW Mie simulations, the refractive index, nλ, is parameterised in terms of the particle radius. The radius and refractive index at 532 nm are determined from PFs, while the refractive index at 405 nm is determined by comparison of the measured Qext to CSW Mie simulations. The refractive indices determined at the shorter wavelength are larger than at the longer wavelength consistent with the expected dispersion behaviour. The measured values at 405 nm are compared to estimates from volume mixing and molar refraction mixing rules, with the latter giving superior agreement. In addition, the first single-particle Qext measurements for accumulation mode aerosol are presented for droplets with radii as small as ∼300 nm.

  14. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    DOEpatents

    Howard, Stanley R [Windsor, SC; Korinko, Paul S [Aiken, SC

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  15. Friction, wear and noise of slip ring and brush contacts for synchronous satellite use.

    NASA Technical Reports Server (NTRS)

    Lewis, N. E.; Cole, S. R.; Glossbrenner, E. W.; Vest, C. E.

    1972-01-01

    A program is being conducted for testing of slip rings for synchronous orbit application. Instrumentation systems necessary for monitoring electrical noise, friction, and brush wear at atmospheric pressure and at less than 50 ntorr have been developed. A multiplex scheme necessary for the simultaneous recording of brush displacement, friction, and electrical noise has also been developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite have been employed on rings of coin silver and rhodium plate. Four contact combinations have been tested during an ambient condition run-in at 150 rpm and a humidity sequence at 0.1 rpm. The first six months of the two year vacuum test at 0.1 rpm have been completed. Electrical noise, friction and brush wear data recorded during these periods have been analyzed.

  16. Co-pyrolysis behavior of fermentation residues with woody sawdust by thermogravimetric analysis and a vacuum reactor.

    PubMed

    Zheng, Yan; Zhang, Yimin; Xu, Jingna; Li, Xiayang; Charles Xu, Chunbao

    2017-12-01

    This study aimed at cost-effective utilization of fermentation residues (FR) from biogas project for bio-energy via co-pyrolysis of FR and woody sawdust (WS). In this study, a vacuum reactor was used to study the pyrolysis behaviors of individual and blend samples of FR and WS. Obvious synergistic effects were observed, resulting in a lower char yield but a higher gas yield. The presence of woody sawdust promoted the devolatilization of FR, and improved the syngas (H 2 and CO) content in the gaseous products. Compared to those of the char from pyrolysis of individual feedstock, co-pyrolysis of FR and WS in the vacuum reactor promoted the cracking reactions of large aromatic rings, enlarged the surface area and reduced the oxygenated groups of the resulted char. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The cryogenic storage ring CSR

    NASA Astrophysics Data System (ADS)

    von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  18. The cryogenic storage ring CSR.

    PubMed

    von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

    2016-06-01

    An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

  19. Vacuum Virtues

    ERIC Educational Resources Information Center

    Rathey, Allen

    2007-01-01

    Upright vacuums, like cars, vary in quality, features and performance. Like automobiles, some uprights are reliable, others may be problematic, and some become a problem as a result of neglect or improper use. So, how do education institutions make an informed choice and, having done so, ensure that an upright vacuum goes the distance? In this…

  20. Microfabricated triggered vacuum switch

    DOEpatents

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  1. Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

    NASA Astrophysics Data System (ADS)

    Cheng, Shaoyong; Xiu, Shixin; Wang, Jimei; Shen, Zhengchao

    2006-11-01

    The greenhouse effect of SF6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.

  2. Integrally Closed Rings

    NASA Astrophysics Data System (ADS)

    Tuganbaev, A. A.

    1982-04-01

    This paper studies integrally closed rings. It is shown that a semiprime integrally closed Goldie ring is the direct product of a semisimple artinian ring and a finite number of integrally closed invariant domains that are classically integrally closed in their (division) rings of fractions. It is shown also that an integrally closed ring has a classical ring of fractions and is classically integrally closed in it.Next, integrally closed noetherian rings are considered. It is shown that an integrally closed noetherian ring all of whose nonzero prime ideals are maximal is either a quasi-Frobenius ring or a hereditary invariant domain.Finally, those noetherian rings all of whose factor rings are invariant are described, and the connection between integrally closed rings and distributive rings is examined.Bibliography: 13 titles.

  3. Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

    2010-10-01

    Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  4. Engineering the bacterial shapes for enhanced inclusion bodies accumulation.

    PubMed

    Jiang, Xiao-Ran; Wang, Huan; Shen, Rui; Chen, Guo-Qiang

    2015-05-01

    Many bacteria can accumulate inclusion bodies such as sulfur, polyphosphate, glycogen, proteins or polyhydroxyalkanoates. To exploit bacteria as factories for effective production of inclusion bodies, a larger intracellular space is needed for more inclusion body accumulation. In this study, polyhydroxybutyrate (PHB) was investigated as an inclusion bodies representative to be accumulated by Escherichia coli JM109SG. Various approaches were taken to increase the bacterial cell sizes including deletion on actin-like protein gene mreB, weak expression of mreB in mreB deletion mutant, and weak expression of mreB in mreB deletion mutant under inducible expression of SulA, the inhibitor of division ring protein FtsZ. All of the methods resulted in different levels of increases in bacterial sizes and PHB granules accumulation. Remarkably, an increase of over 100% PHB accumulation was observed in recombinant E. coli overexpressing mreB in an mreB deletion mutant under inducible expression of FtsZ inhibiting protein SulA. The molecular mechanism of enlarged bacterial size was found to be directly relate to weakened cytoskeleton which was the result of broken skeleton helix. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  5. On Organic Material in E Ring Ice Grains

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Khawaja, N.; Reviol, R.; Nölle, L.; Klenner, F.; Hsu, H. W.; Horanyi, M.

    2015-12-01

    Pure water ice dominates the composition of the micron and sub-micron sized dust particles in Saturn's E-ring, a ring constantly replenished by active ice jets of the moon Enceladus [1]. Details about the composition of this tenuous, optically thin ring can only be constrained by in situ measurements. The Cosmic Dust Analyzer (CDA) onboard Cassini investigates the composition of these grains by cationic time-of-flight mass spectra of individual ice grains hitting the instruments target surface. From these spectra three compositional types of E ring ice grains have been identified previously [2,3]: Type-1: Almost pure water, Type-2: Enriched in organics, and Type-3: Enriched in salt. Unlike Type-1 and 3, organic-enriched Type-2 spectra have not yet been investigated in depth. Here we report the first detailed compositional analysis of this type. The spectra analysis is supported by a large-scale laboratory ground campaign yielding a library of analogue spectra for organic material embedded in a water ice matrix. In contrast to Type 1 and 3, Type-2 spectra display a great compositional diversity, which indicates varying contributions of several organic species. So far we have identified characteristic fragment patterns of at least three classes of organic compounds: aromatic species, amines, and carbonyl group species. Work is in progress to quantify concentrations of the identified species and to assign yet un-specified organic mass lines in Type 2 spectra. Due to the dynamical evolution of the orbital elements of E ring grains a large fraction collides with the icy moons embedded in the E ring. Therefore, the organic components identified by CDA can accumulate on the surfaces of these bodies over time. Ref: :[1]Kempf et al., Icarus-206, 2010. [2]Postberg et al., Nature-459, 2009. [3]Postberg et al., Icarus-193, 2008.

  6. Ring-like spatial distribution of laser accelerated protons in the ultra-high-contrast TNSA-regime

    NASA Astrophysics Data System (ADS)

    Becker, G. A.; Tietze, S.; Keppler, S.; Reislöhner, J.; Bin, J. H.; Bock, L.; Brack, F.-E.; Hein, J.; Hellwing, M.; Hilz, P.; Hornung, M.; Kessler, A.; Kraft, S. D.; Kuschel, S.; Liebetrau, H.; Ma, W.; Polz, J.; Schlenvoigt, H.-P.; Schorcht, F.; Schwab, M. B.; Seidel, A.; Zeil, K.; Schramm, U.; Zepf, M.; Schreiber, J.; Rykovanov, S.; Kaluza, M. C.

    2018-05-01

    The spatial distribution of protons accelerated from submicron-thick plastic foil targets using multi-terawatt, frequency-doubled laser pulses with ultra-high temporal contrast has been investigated experimentally. A very stable, ring-like beam profile of the accelerated protons, oriented around the target’s normal direction has been observed. The ring’s opening angle has been found to decrease with increasing foil thicknesses. Two-dimensional particle-in-cell simulations reproduce our results indicating that the ring is formed during the expansion of the proton density distribution into the vacuum as described by the mechanism of target-normal sheath acceleration. Here—in addition to the longitudinal electric fields responsible for the forward acceleration of the protons—a lateral charge separation leads to transverse field components accelerating the protons in the lateral direction.

  7. Ring dynamics

    NASA Technical Reports Server (NTRS)

    Borderies, Nicole

    1989-01-01

    Theoretical models of planetary-ring dynamics are discussed in a detailed analytical review and illustrated with graphs and diagrams. The streamline concept is introduced, and the phenomena associated with the transport of angular momentum are described. Particular attention is then given to (1) broad rings like those of Saturn (shepherding, density-wave excitation, gaps, bending-wave excitation, multiringlet structures, inner-edge shepherding, and the possibility of polar rings around Neptune), (2) narrow rings like those of Uranus (shepherding, ring shapes, and a self-gravity model of rigid precession), and (3) ring arcs like those seen in stellar-occultation observations of Neptune.

  8. Monitoring Snow on ice as Critical Habitat for Ringed Seals

    NASA Astrophysics Data System (ADS)

    Kelly, B. P.; Moran, J.; Douglas, D. C.; Nghiem, S. V.

    2007-12-01

    Ringed seals are the primary prey of polar bears, and they are found in all seasonally ice covered seas of the northern hemisphere as well as in several freshwater lakes. The presence of snow covered sea ice is essential for successful ringed seal reproduction. Ringed seals abrade holes in the ice allowing them to surface and breathe under the snow cover. Where snow accumulates to sufficient depths, ringed seals excavate subnivean lairs above breathing holes. They rest, give birth, and nurse their young in those lairs. Temperatures within the lairs remain within a few degrees of freezing, well within the zone of thermal neutrality for newborn ringed seals, even at ambient temperatures of -30° C. High rates of seal mortality have been recorded when early snow melt caused lairs to collapse exposing newborn seals to predators and to subsequent extreme cold events. As melt onset dates come earlier in the Arctic Ocean, ringed seal populations (and the polar bears that depend upon them) will be increasingly challenged. We determined dates of lair abandonment by ringed seals fitted with radio transmitters in the Beaufort Sea (n = 60). We compared abandonment dates to melt onset dates measured in the field, as well as estimated dates derived from active (Ku-band backscatter) and passive (SSM/I) microwave satellite imagery. Date of snow melt significantly improved models of environmental influences on the timing of lair abandonment. We used an algorithm based on multi-channel means and variances of passive microwave data to detect melt onset dates. Those melt onset dates predicted the date of lair abandonment ± 3 days (r 2 = 0.982, p = 0.001). The predictive power of passive microwave proxies combined with their historical record suggest they could serve to monitor critical changes to ringed seal habitat.

  9. Vacuum probe surface sampler

    NASA Technical Reports Server (NTRS)

    Zahlava, B. A. (Inventor)

    1973-01-01

    A vacuum probe surface sampler is described for rapidly sampling relatively large surface areas which possess relatively light loading densities of micro-organism, drug particles or the like. A vacuum head with a hollow handle connected to a suitable vacuum source is frictionally attached to a cone assembly terminating in a flared tip adapted to be passed over the surface to be sampled. A fine mesh screen carried by the vacuum head provides support for a membrane filter which collects the microorganisms or other particles. The head assembly is easily removed from the cone assembly without contacting the cone assembly with human hands.

  10. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  11. The role of Mab as a source for the μ ring of Uranus

    NASA Astrophysics Data System (ADS)

    Sfair, R.; Giuliatti Winter, S. M.

    2012-07-01

    Context. We previously analysed how the solar radiation force combined with the planetary oblateness changes the orbital evolution of a sample of dust particles located at the secondary ring system of Uranus. Both effects combined with the gravitational perturbations of the close satellites lead to the depletion of these dust particles through collisions on the surfaces of these satellites on a timescale of hundreds of years. Aims: In this work we investigate if the impacts of interplanetary dust particles (IDPs) onto Mab's surface can produce sufficient particles to replenish the μ ring population. Methods: We first analysed through numerical simulations the evolution of a sample of particles ejected from the surface of Mab and computed the lifetime of the grains when the effects of the solar radiation pressure and the planetary oblateness are taken into account. Then we estimated the mass production rate due to the impacts of IDPs following a previously established algorithm, and used this value to determine the time necessary to accumulate an amount of particles comparable with the mass of the μ ring. Results: Based on an estimate of the flux of interplanetary particles and on the surface properties of Mab it is expected that the satellite supplies material to the ring at a rate of ~3 g/s. Meanwhile, our numerical model showed that the ejected particles are removed from the system through collisions with the satellite, and the mean lifetime of the grains may vary from 320 to 1500 years, depending on the radius of the particle. Conclusions: The time necessary to accumulate the mass of the μ ring via ejection from Mab is much shorter than the mean lifetime of the particles, and a stationary regime is not reached. If the ring is kept in a steady state, other effects such as the electromagnetic force and/or the existence of additional bodies may play a significant role in the dust balance, but the current lack of information about the environment renders

  12. Identification and deconvolution of carbohydrates with gas chromatography-vacuum ultraviolet spectroscopy.

    PubMed

    Schenk, Jamie; Nagy, Gabe; Pohl, Nicola L B; Leghissa, Allegra; Smuts, Jonathan; Schug, Kevin A

    2017-09-01

    Methodology for qualitative and quantitative determination of carbohydrates with gas chromatography coupled to vacuum ultraviolet detection (GC-VUV) is presented. Saccharides have been intently studied and are commonly analyzed by gas chromatography-mass spectrometry (GC-MS), but not always effectively. This can be attributed to their high degree of structural complexity: α/β anomers from their axial/equatorial hydroxyl group positioning at the C1-OH and flexible ring structures that lead to the open chain, five-membered ring furanose, and six-membered ring pyranose configurations. This complexity can result in convoluted chromatograms, ambiguous fragmentation patterns and, ultimately, analyte misidentification. In this study, mono-, di, and tri-saccharides were derivatized by two different methods-permethylation and oximation/pertrimethylsilylation-and analyzed by GC-VUV. These two derivatization methods were then compared for their efficiency, ease of use, and robustness. Permethylation proved to be a useful technique for the analysis of ketopentoses and pharmaceuticals soluble in dimethyl sulfoxide (DMSO), while the oximation/pertrimethylsilylation method prevailed as the more promising, overall, derivatization method. VUV spectra have been shown to be distinct and allow for efficient differentiation of isomeric species such as ketopentoses and reducing versus non-reducing sugars. In addition to identification, pharmaceutical samples containing several compounds were derivatized and analyzed for their sugar content with the GC-VUV technique to provide data for qualitative analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Comparison of work rates, energy expenditure, and perceived exertion during a 1-h vacuuming task with a backpack vacuum cleaner and an upright vacuum cleaner.

    PubMed

    Mengelkoch, Larry J; Clark, Kirby

    2006-03-01

    The purpose of this study was to evaluate two types of industrial vacuum cleaners, in terms of cleaning rates, energy expenditure, and perceived exertion. Twelve industrial cleaners (six males and six females, age 28-39 yr) performed two 1-h vacuuming tasks with an upright vacuum cleaner (UVC) and a backpack vacuum cleaner (BPVC). Measures for oxygen uptake (VO2) and ratings of perceived exertion (RPE) were collected continuously during the 1-h vacuuming tasks. Cleaning rates for the UVC and BPVC were 7.23 and 14.98 m2min(-1), respectively. On a separate day subjects performed a maximal treadmill exercise test to determine their maximal aerobic capacity (peak VO2). Average absolute energy costs (in Metabolic equivalents), relative energy costs of the vacuum task compared to the subjects' maximal aerobic capacity (% peak VO2), and RPE responses for the 1-h vacuuming tasks were similar between vacuum cleaners, but % peak VO2 and RPE values differed between genders. These results indicate that the BPVC was more efficient than the UVC. With the BPVC, experienced workers vacuumed at a cleaning rate 2.07 times greater than the UVC and had similar levels of energy expenditure and perceived effort, compared to the slower cleaning rate with the UVC.

  14. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  15. Exploring vacuum birefringence based on a 100 PW laser and an x-ray free electron laser beam

    NASA Astrophysics Data System (ADS)

    Shen, Baifei; Bu, Zhigang; Xu, Jiancai; Xu, Tongjun; Ji, Liangliang; Li, Ruxin; Xu, Zhizhan

    2018-04-01

    Exploring vacuum birefringence with the station of extreme light at Shanghai Coherent Light Facility is considered. Laser pulses of intensity beyond 1023 W cm-2 are capable of polarizing the vacuum due to the ultra-strong electro-magnetic fields. The subtle difference of the vacuum refractive indexes along electric and magnetic fields leads to a birefringence effect for lights propagating through. The vacuum birefringence effect can now be captured by colliding a hard x-ray free electron laser (XFEL) beam with a high-power laser. The initial XFEL beam of pure linear polarization is predicated to gain a very small ellipticity after passing through the laser stimulated vacuum. Various interaction geometries are considered, showing that the estimated ellipticity lies between 1.8 × 10-10 and 10-9 for a 100 PW laser interacting with a 12.9 keV XFEL beam, approaching the threshold for todays’ polarity detection technique. The detailed experimental set-up is designed, including the polarimeter, the focusing compound refractive lens and the optical path. When taking into account the efficiencies of the x-ray instruments, it is found that about 10 polarization-flipped x-ray photons can be detected for a single shot for our design. Considering the background noise level, accumulating runs are necessary to obtain high confident measurement.

  16. A radiation hard vacuum switch

    DOEpatents

    Boettcher, G.E.

    1988-07-19

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

  17. Planetary rings as relics of plasma pre-rings

    NASA Astrophysics Data System (ADS)

    Rabinovich, B. I.

    2007-02-01

    A possibility is discussed that the rings of large planets observed in the modern epoch are relics of some pre-rings consisting of magnetized plasma (according to a hypothesis by H. Alfven). The solution to a model problem published in [36, 37] is used. Its main result is a mechanism of stratification of an evolutionally mature plasma pre-ring into a large number of narrow elite rings separated by anti-rings (gaps). Another result is the theoretical substantiation of the presence in the near-planetary space of a region of existence and stability (in what follows it is referred to as ES-region) of plasma rings. The data obtained in the course of the Voyager, Galileo, and Cassini missions are used below for verification of the model on which the solutions presented in [36, 37] are based.

  18. Comparison of vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification systems.

    PubMed

    Han, Young Keun; Miller, Kevin M

    2009-08-01

    To compare vacuum rise time, vacuum limit accuracy, and occlusion break surge of 3 new phacoemulsification machines. Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA. The vacuum rise time under normal and enhanced aspiration modes, vacuum limit accuracy, and occlusion break surge of the Infiniti Vision System, Stellaris Vision Enhancement System, and WhiteStar Signature Phacoemulsification System were tested. Vacuum rise time and limit accuracy were measured at limit settings of 400 mm Hg and 600 mm Hg. Surge area was recorded at vacuum limit settings of 200 mm Hg, 300 mm Hg, 400 mm Hg, and 500 mm Hg. The Infiniti had the fastest vacuum rise times under normal and enhanced aspiration modes. At 4 seconds, the vacuum limit accuracy was greatest with the Infiniti at the 400 mm Hg limit and the Signature at the 600 mm Hg limit. The Stellaris did not reach either vacuum target. The Infiniti performed better than the other 2 machines during testing of occlusion break surge at all vacuum limit settings above 200 mm Hg. Under controlled laboratory test conditions, the Infiniti had the fastest vacuum rise time, greatest vacuum limit accuracy at 400 mm Hg, and least occlusion break surge. These results can be explained by the lower compliance of the Infiniti system.

  19. Causes of Ring-Related Leg Injuries in Birds – Evidence and Recommendations from Four Field Studies

    PubMed Central

    Griesser, Michael; Schneider, Nicole A.; Collis, Mary-Anne; Overs, Anthony; Guppy, Michael; Guppy, Sarah; Takeuchi, Naoko; Collins, Pete; Peters, Anne; Hall, Michelle L.

    2012-01-01

    One of the main techniques for recognizing individuals in avian field research is marking birds with plastic and metal leg rings. However, in some species individuals may react negatively to rings, causing leg injuries and, in extreme cases, the loss of a foot or limb. Here, we report problems that arise from ringing and illustrate solutions based on field data from Brown Thornbills (Acanthiza pusilla) (2 populations), Siberian Jays (Perisoreus infaustus) and Purple-crowned Fairy-wrens (Malurus coronatus). We encountered three problems caused by plastic rings: inflammations triggered by material accumulating under the ring (Purple-crowned Fairy-wrens), contact inflammations as a consequence of plastic rings touching the foot or tibio-tarsal joint (Brown Thornbills), and toes or the foot getting trapped in partly unwrapped flat-band colour rings (Siberian Jays). Metal rings caused two problems: the edges of aluminium rings bent inwards if mounted on top of each other (Brown Thornbills), and too small a ring size led to inflammation (Purple-crowned Fairy-wrens). We overcame these problems by changing the ringing technique (using different ring types or larger rings), or using different adhesive. Additionally, we developed and tested a novel, simple technique of gluing plastic rings onto metal rings in Brown Thornbills. A review of studies reporting ring injuries (N = 23) showed that small birds (<55 g body weight) are more prone to leg infections while larger birds (>35 g) tend to get rings stuck over their feet. We give methodological advice on how these problems can be avoided, and suggest a ringing hazard index to compare the impact of ringing in terms of injury on different bird species. Finally, to facilitate improvements in ringing techniques, we encourage online deposition of information regarding ringing injuries of birds at a website hosted by the European Union for Bird Ringing (EURING). PMID:23300574

  20. Photon-induced tunability of the thermospin current in a Rashba ring

    NASA Astrophysics Data System (ADS)

    Abdullah, Nzar Rauf; Arnold, Thorsten; Tang, Chi-Shung; Manolescu, Andrei; Gudmundsson, Vidar

    2018-04-01

    The goal of this work is to show how the thermospin polarization current in a quantum ring changes in the presence of Rashba spin-orbit coupling and a quantized single photon mode of a cavity the ring is placed in. Employing the reduced density operator and a general master equation formalism, we find that both the Rashba interaction and the photon field can significantly modulate the spin polarization and the thermospin polarization current. Tuning the Rashba coupling constant, degenerate energy levels are formed corresponding to the Aharonov-Casher destructive phase interference in the quantum ring system. Our analysis indicates that the maximum spin polarization can be observed at the points of degenerate energy levels due to spin accumulation in the system without the photon field. The thermospin current is thus suppressed. In the presence of the cavity, the photon field leads to an additional kinetic momentum of the electron. As a result the spin polarization can be enhanced by the photon field.

  1. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Gordon, M. K.; Araki, S.; Black, G. J.; Bosh, A. S.; Brahic, A.; Brooks, S. M.; Charnoz, S.; Colwell, J. E.; Cuzzi, J. N.; Dones, L.; Durisen, R. H.; Esposito, L. W.; Ferrari, C.; Festou, M.; French, R. G.; Giuliatti-Winter, S. M.; Graps, A. L.; Hamilton, D. P.; Horanyi, M.; Karjalainen, R. M.; Krivov, A. V.; Krueger, H.; Larson, S. M.; Levison, H. F.; Lewis, M. C.; Lissauer, J. J.; Murray, C. D.; Namouni, F.; Nicholson, P. D.; Olkin, C. B.; Poulet, F.; Rappaport, N. J.; Salo, H. J.; Schmidt, J.; Showalter, M. R.; Spahn, F.; Spilker, L. J.; Srama, R.; Stewart, G. R.; Yanamandra-Fisher, P.

    2002-08-01

    The past two decades have witnessed dramatic changes in our view and understanding of planetary rings. We now know that each of the giant planets in the Solar System possesses a complex and unique ring system. Recent studies have identified complex gravitational interactions between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto, or collisions between, parent bodies. Yet, as far as we have come, our understanding is far from complete. The fundamental questions confronting ring scientists at the beginning of the twenty-first century are those regarding the origin, age and evolution of the various ring systems, in the broadest context. Understanding the origin and age requires us to know the current ring properties, and to understand the dominant evolutionary processes and how they influence ring properties. Here we discuss a prioritized list of the key questions, the answers to which would provide the greatest improvement in our understanding of planetary rings. We then outline the initiatives, missions, and other supporting activities needed to address those questions, and recommend priorities for the coming decade in planetary ring science.

  2. Air bearing vacuum seal assembly

    DOEpatents

    Booth, Rex

    1978-01-01

    An air bearing vacuum seal assembly capable of rotating at the speed of several thousand revolutions per minute using an air cushion to prevent the rotating and stationary parts from touching, and a two stage differential pumping arrangement to maintain the pressure gradient between the air cushion and the vacuum so that the leak rate into the vacuum is, for example, less than 1 .times. 10.sup.-4 Pa m.sup.3 /s. The air bearing vacuum seal has particular application for mounting rotating targets to an evacuated accelerator beam tube for bombardment of the targets with high-power charged particle beams in vacuum.

  3. Vacuum-Gauge Connection For Shipping Container

    NASA Technical Reports Server (NTRS)

    Henry, Robert H.

    1990-01-01

    External connector enables measurement of vacuum in stored part. Remote-readout connector added to shipping container and connected to thermo-couple vacuum gauge in vacuum-insulated cryogenic line packed in container. Enables monitoring of condition of vacuum without opening container.

  4. Development and fabrication of the vacuum systems for an elliptically polarized undulator at Taiwan Photon Source

    NASA Astrophysics Data System (ADS)

    Chang, Chin-Chun; Chan, Che-Kai; Wu, Ling-Hui; Shueh, Chin; Shen, I.-Ching; Cheng, Chia-Mu; Yang, I.-Chen

    2017-05-01

    Three sets of a vacuum system were developed and fabricated for elliptically polarized undulators (EPU) of a 3-GeV synchrotron facility. These chambers were shaped with low roughness extrusion and oil-free machining; the design combines aluminium and stainless steel. The use of a bimetallic material to connect the EPU to the vacuum system achieves the vacuum sealing and to resolve the leakage issue due to bake process induced thermal expansion difference. The interior of the EPU chamber consists of a non-evaporable-getter strip pump in a narrow space to absorb photon-stimulated desorption and to provide a RF bridge design to decrease impedance effect in the two ends of EPU chamber. To fabricate these chambers and to evaluate the related performance, we performed a computer simulation to optimize the structure. During the machining and welding, the least deformation was achieved, less than 0.1 mm near 4 m. In the installation, the linear slider can provide a stable and precision moved along parallel the electron beam direction smoothly for the EPU chamber to decrease the twist issue during baking process. The pressure of the EPU chamber attained less than 2×10-8 Pa through baking. These vacuum systems of the EPU magnet have been installed in the electron storage ring of Taiwan Photon Source in 2015 May and have normally operated at 300 mA continuously since, and to keep beam life time achieved over than 12 h.

  5. Effective Porosity Measurements by Wet- and Dry-type Vacuum Saturations using Process-Programmable Vacuum Saturation System

    NASA Astrophysics Data System (ADS)

    Lee, T. J.; Lee, K. S., , Dr; Lee, S. K.

    2017-12-01

    One of the most important factors in measuring effective porosity by vacuum saturation method is that the air in the pore space can be fully substituted by water during the vacuum saturation process. International Society of Rock Mechanics (ISRM) suggests vacuuming a rock sample submerged in the water, while American Society of Test and Materials (ASTM) vacuuming the sample and water separately and then pour the water to the sample. In this study, we call the former wet-type vacuum saturation (WVS) method and the latter dry-type vacuum saturation (DVS) method, and compare the effective porosity measured by the two different vacuum saturation processes. For that purpose, a vacuum saturation system has been developed, which can support both WVS and DVS by only changing the process by programming. Comparison of effective porosity has been made for a cement mortar and rock samples. As a result, DVS can substitute more void volume to water than WVS, which in turn insists that DVS can provide more exact value of effective porosity than WVS.

  6. Saturn's Rings, the Yarkovsky Effects, and the Ring of Fire

    NASA Technical Reports Server (NTRS)

    Rubincam, David

    2004-01-01

    Saturn's icy ring particles, with their low thermal conductivity, are almost ideal for the operation of the Yarkovsky effects. The dimensions of Saturn's A and B rings may be determined by a near balancing of the seasonal Yarkovsky effect with the Yarkovsky- Schach effect. The two effects, which are photon thrust due to temperature gradients, may confine the A and B rings to within their observed dimensions. The C ring may be sparsely populated with icy particles because Yarkovsky drag has pulled them into Saturn, leaving the more slowly orbitally decaying rocky particles. Icy ring particles ejected from the B ring and passing through the C ring, as well as some of the slower rocky particles, should fall on Saturn's equator, where they may create a luminous "Ring of Fire" around Saturn's equator. This predicted Ring of Fire may be visible to Cassini's camera. Curiously, the speed of outwards Yarkovsky orbital evolution appears to peak near the Cassini Division. The connection between the two is not clear. D. Nesvorny has speculated that the resonance at the outer edge of the B ring may impede particles from evolving via Yarkovsky across the Division. If supply from the B ring is largely cut off, then Yarkovsky may push icy particles outward, away from the inner edge of the A ring, leaving only the rocky ones in the Division. The above scenarios depend delicately on the properties of the icy particles.

  7. Variations in Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Déau, E.; Altobelli, N.

    2010-12-01

    Cassini's Composite Infrared Spectrometer has recorded over two million of spectra of Saturn's rings in the far infrared since arriving at Saturn in 2004. CIRS records far infrared radiation between 10 and 600 cm-1 ( 16.7 and 1000 μ {m} ) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn’s rings peaks in this wavelength range. Ring temperatures can be inferred from FP1 data. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and rapidly changing temperatures are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid particles can be expected to have higher thermal inertias. Ferrari et al. (2005) fit thermal inertia values of 5218 {Jm)-2 {K}-1 {s}-1/2 to their B ring data and 6412 {Jm)-2 {K}-1 {s}-1/2 to their C ring data. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The rings’ thermal budget is dominated by its absorption of solar radiation. As a result, ring particles abruptly cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  8. Vortex rings

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Leonard, Anthony

    1992-01-01

    The vortex-ring problem in fluid mechanics is examined generally in terms of formation, the steady state, the duration of the rings, and vortex interactions. The formation is studied by examining the generation of laminar and turbulent vortex rings and their resulting structures with attention given to the three stages of laminar ring development. Inviscid dynamics is addressed to show how core dynamics affects overall ring motion, and laminar vortex structures are described in two dimensions. Viscous and inviscid structures are related in terms of 'leapfrogging', head-on collisions, and collisions with a no-slip wall. Linear instability theory is shown to successfully describe observational data, although late stages in the breakdown are not completely understood. This study of vortex rings has important implications for key aerodynamic issues including sound generation, transport and mixing, and vortex interactions.

  9. Expected first-order effects of a notional equatorial ring on Earth's night sky: a geometric consideration

    NASA Astrophysics Data System (ADS)

    Hancock, L. O.

    2013-12-01

    G. Jones (1856) was first to suggest that the Earth might have its own ring, noting that an Earth ring in the ecliptic plane would account for the latitude dependence of the zodiacal light. Jones's proposal was not accepted: it is difficult to see why the ecliptic would accumulate mass within the Earth-Moon system. Very recently, however, this objection has been mitigated by the discovery of Saturn's Phoebe ring: evidently, the plane of a planetary moon's orbit has now been observed as the site of mass accumulation. An adjustment of just a few degrees from ecliptic to the plane of the lunar orbit gives Jones's proposal the boost of an existing Solar System analogue, mysterious though the analogue is. J. O'Keefe (1980) was first to suggest that an Earth ring system could drive climate: a ring in the equatorial plane, waxing and waning in optical depth, could drive the alternation of Ice Age and interglacial climates. This driver would account for the observation that the Ice Age climate was mainly a difference in winter only. Could Earth have a ring system with one or both elements? Even if light and unstable, it would be important to assess, as it could drive climate change. Dust assessments have not discovered a ring system, but they do not cover low orbits well, nor rule out very small particles stringently. Yet tiny particles can be optically important. There are many difficulties with this hypothesis: Why have ground-based observers never identified an equatorial ring, which after all should be the brightest element of a ring system? Why should a ring system be made of very small particles only? The material must be constantly falling to Earth - where is it? Finally, can we believe in the level of lunar geological activity needed to sustain an Earth ring system? This presentation addresses only one issue: Could ground-based observers have seen but misidentified an equatorial ring? To support consideration of that question, herewith a simple geometric exercise

  10. Asymmetric dipolar ring

    DOEpatents

    Prosandeev, Sergey A.; Ponomareva, Inna V.; Kornev, Igor A.; Bellaiche, Laurent M.

    2010-11-16

    A device having a dipolar ring surrounding an interior region that is disposed asymmetrically on the ring. The dipolar ring generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar ring in the plane of the ring. The ring may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.

  11. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOEpatents

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  12. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOEpatents

    Kuklo, T.C.

    1999-07-20

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings. 2 figs.

  13. Multipurpose Vacuum Induction Processing System

    NASA Astrophysics Data System (ADS)

    Govindaraju, M.; Kulkarni, Deepak; Balasubramanian, K.

    2012-11-01

    Multipurpose vacuum processing systems are cost effective; occupy less space, multiple functional under one roof and user friendly. A multipurpose vacuum induction system was designed, fabricated and installed in a record time of 6 months time at NFTDC Hyderabad. It was designed to function as a) vacuum induction melting/refining of oxygen free electronic copper/pure metals, b) vacuum induction melting furnace for ferrous materials c) vacuum induction melting for non ferrous materials d) large vacuum heat treatment chamber by resistance heating (by detachable coil and hot zone) e) bottom discharge vacuum induction melting system for non ferrous materials f) Induction heat treatment system and g) directional solidification /investment casting. It contains provision for future capacity addition. The attachments require to manufacture multiple shaped castings and continuous rod casting can be added whenever need arises. Present capacity is decided on the requirement for 10years of development path; presently it has 1.2 ton liquid copper handling capacity. It is equipped with provision for capacity addition up to 2 ton liquid copper handling capacity in future. Provision is made to carry out the capacity addition in easy steps quickly. For easy operational maintenance and troubleshooting, design was made in easily detachable sections. High vacuum system is also is detachable, independent and easily movable which is first of its kind in the country. Detailed design parameters, advantages and development history are presented in this paper.

  14. Vacuum leak detector and method

    DOEpatents

    Edwards, Jr., David

    1983-01-01

    Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

  15. Robot design for a vacuum environment

    NASA Technical Reports Server (NTRS)

    Belinski, S.; Trento, W.; Imani-Shikhabadi, R.; Hackwood, S.

    1987-01-01

    The cleanliness requirements for many processing and manufacturing tasks are becoming ever stricter, resulting in a greater interest in the vacuum environment. Researchers discuss the importance of this special environment, and the development of robots which are physically and functionally suited to vacuum processing tasks. Work is in progress at the Center for robotic Systems in Microelectronics (CRSM) to provide a robot for the manufacture of a revolutionary new gyroscope in high vacuum. The need for vacuum in this and other processes is discussed as well as the requirements for a vacuum-compatible robot. Finally, researchers present details on work done at the CRSM to modify an existing clean-room compatible robot for use at high vacuum.

  16. Saturn's Rings, the Yarkovsky Effects, and the Ring of Fire

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    2004-01-01

    The dimensions of Saturn's A and B rings may be determined by the seasonal Yarkovsky effect and the Yarkovsky-Schach effect; the two effects confine the rings between approximately 1.68 and approximately 2.23 Saturn radii, in reasonable agreement with the observed values of 1.525 and 2.267. The C ring may be sparsely populated because its particles are transients on their way to Saturn; the infall may create a luminous Ring of Fire around Saturn's equator. The ring system may be young: in the past heat flow from Saturn's interior much above its present value would not permit rings to exist.

  17. Saturn's largest ring.

    PubMed

    Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P

    2009-10-22

    Most planetary rings in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer rings and Saturn's E ring, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous ring associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The ring's vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these ring particles span the Saturnian system from the main rings to the edges of interplanetary space. The ring's normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer ring, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the ring populated with material. Ring particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.

  18. Slowing down of ring polymer diffusion caused by inter-ring threading.

    PubMed

    Lee, Eunsang; Kim, Soree; Jung, YounJoon

    2015-06-01

    Diffusion of long ring polymers in a melt is much slower than the reorganization of their internal structures. While direct evidence for entanglements has not been observed in the long ring polymers unlike linear polymer melts, threading between the rings is suspected to be the main reason for slowing down of ring polymer diffusion. It is, however, difficult to define the threading configuration between two rings because the rings have no chain end. In this work, evidence for threading dynamics of ring polymers is presented by using molecular dynamics simulation and applying a novel analysis method. The simulation results are analyzed in terms of the statistics of persistence and exchange times that have proved useful in studying heterogeneous dynamics of glassy systems. It is found that the threading time of ring polymer melts increases more rapidly with the degree of polymerization than that of linear polymer melts. This indicates that threaded ring polymers cannot diffuse until an unthreading event occurs, which results in the slowing down of ring polymer diffusion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Technical specification for vacuum systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khaw, J.

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10/sup -5/ to 10/sup -11/ Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing andmore » designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components. (LEW)« less

  20. Simulated microbe removal around finger rings using different hand sanitation methods.

    PubMed

    Alur, Archana A; Rane, Madhavi J; Scheetz, James P; Lorenz, Douglas J; Gettleman, Lawrence

    2009-09-01

    It is our opinion that the CDC and the WHO have underestimated cross-contamination under examination gloves in dental clinics while wearing jewelry, such as finger rings. These agencies only "recommend" removing jewelry, and only washing hands for 15 seconds with soap and warm water before donning gloves. This study examined several washing procedures and finger rings using simulated microbes. A gloved rubber hand manikin was made and fitted with a fresh disposable vinyl glove. Four fingers were fitted with rings or no ring, dusted with simulated microbes, and washed with a scrub brush for 5, 15, and 25 seconds under 20 degrees C and 40 degrees C water alone, or with liquid hand soap. Light levels (in lux) of fluorescent powder before and after washing were measured and delta scores calculated for changes in light levels, equivalent to effectiveness of hand washing procedures. A full-factorial, 3-factor analysis of variance (ANOVA) was used to test for differences among levels of the three study factors-time, temperature, and soap use. Tukey's post hoc honestly significant difference (HSD) test was applied to significant factors to examine pair-wise differences between factor levels. It was found that the longer the hands with rings were washed with a scrub brush under flowing water, the more simulated microbes were removed. By 25 seconds, all methods were essentially the same. Simulated microbes were more difficult to remove from the palm compared to the back of the hand. The liquid hand soap used in this study was more effective with warm water than cold. When given a choice of washing with cold water up to 15 seconds, it would be preferable not to use soap to remove simulated microbes. Qualitatively, the outer surface of finger rings were more effectively cleaned than the crevice below the ring, and the ring with a stone setting appeared to accumulate and retain simulated microbes more than other rings. The most effective treatment was washing with warm water

  1. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Taylor, Daniel M.; Soules, David M.; Barengoltz, Jack B.

    1995-01-01

    Vacuum-bakeout apparatus for decontaminating and measuring outgassing from pieces of equipment constructed by mounting bakeout chamber within conventional vacuum chamber. Upgrade cost effective: fabrication and installation of bakeout chamber simple, installation performed quickly and without major changes in older vacuum chamber, and provides quantitative data on outgassing from pieces of equipment placed in bakeout chamber.

  2. Uranus Tenth Ring

    NASA Image and Video Library

    1996-01-29

    On Jan. 23, 1986, NASA Voyager 2 discovered a tenth ring orbiting Uranus. The tenth ring is about midway between the bright, outermost epsilon ring and the next ring down, called delta. http://photojournal.jpl.nasa.gov/catalog/PIA00035

  3. Catabolism of the Last Two Steroid Rings in Mycobacterium tuberculosis and Other Bacteria.

    PubMed

    Crowe, Adam M; Casabon, Israël; Brown, Kirstin L; Liu, Jie; Lian, Jennifer; Rogalski, Jason C; Hurst, Timothy E; Snieckus, Victor; Foster, Leonard J; Eltis, Lindsay D

    2017-04-04

    Most mycolic acid-containing actinobacteria and some proteobacteria use steroids as growth substrates, but the catabolism of the last two steroid rings has yet to be elucidated. In Mycobacterium tuberculosis , this pathway includes virulence determinants and has been proposed to be encoded by the KstR2-regulated genes, which include a predicted coenzyme A (CoA) transferase gene ( ipdAB ) and an acyl-CoA reductase gene ( ipdC ). In the presence of cholesterol, Δ ipdC and Δ ipdAB mutants of either M. tuberculosis or Rhodococcus jostii strain RHA1 accumulated previously undescribed metabolites: 3aα- H -4α(carboxyl-CoA)-5-hydroxy-7aβ-methylhexahydro-1-indanone (5-OH HIC-CoA) and ( R )-2-(2-carboxyethyl)-3-methyl-6-oxocyclohex-1-ene-1-carboxyl-CoA (COCHEA-CoA), respectively. A Δ fadE32 mutant of Mycobacterium smegmatis accumulated 4-methyl-5-oxo-octanedioic acid (MOODA). Incubation of synthetic 5-OH HIC-CoA with purified IpdF, IpdC, and enoyl-CoA hydratase 20 (EchA20), a crotonase superfamily member, yielded COCHEA-CoA and, upon further incubation with IpdAB and a CoA thiolase, yielded MOODA-CoA. Based on these studies, we propose a pathway for the final steps of steroid catabolism in which the 5-member ring is hydrolyzed by EchA20, followed by hydrolysis of the 6-member ring by IpdAB. Metabolites accumulated by Δ ipdF and Δ echA20 mutants support the model. The conservation of these genes in known steroid-degrading bacteria suggests that the pathway is shared. This pathway further predicts that cholesterol catabolism yields four propionyl-CoAs, four acetyl-CoAs, one pyruvate, and one succinyl-CoA. Finally, a Δ ipdAB M. tuberculosis mutant did not survive in macrophages and displayed severely depleted CoASH levels that correlated with a cholesterol-dependent toxicity. Our results together with the developed tools provide a basis for further elucidating bacterial steroid catabolism and virulence determinants in M. tuberculosis. IMPORTANCE Bacteria are the

  4. Jupiter Ring Halo

    NASA Image and Video Library

    1998-03-26

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest being

  5. Birth Control Ring

    MedlinePlus

    ... Safe Videos for Educators Search English Español Birth Control Ring KidsHealth / For Teens / Birth Control Ring What's in this article? What Is It? ... Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ring ...

  6. Space Suit Portable Life Support System (PLSS) 2.0 Unmanned Vacuum Environment Testing

    NASA Technical Reports Server (NTRS)

    Watts, Carly; Vogel, Matthew

    2016-01-01

    For the first time in more than 30 years, an advanced space suit Portable Life Support System (PLSS) design was operated inside a vacuum chamber representative of the flight operating environment. The test article, PLSS 2.0, was the second system-level integrated prototype of the advanced PLSS design, following the PLSS 1.0 Breadboard that was developed and tested throughout 2011. Whereas PLSS 1.0 included five technology development components with the balance the system simulated using commercial-off-the-shelf items, PLSS 2.0 featured first generation or later prototypes for all components less instrumentation, tubing and fittings. Developed throughout 2012, PLSS 2.0 was the first attempt to package the system into a flight-like representative volume. PLSS 2.0 testing included an extensive functional evaluation known as Pre-Installation Acceptance (PIA) testing, Human-in-the-Loop testing in which the PLSS 2.0 prototype was integrated via umbilicals to a manned prototype space suit for 19 two-hour simulated EVAs, and unmanned vacuum environment testing. Unmanned vacuum environment testing took place from 1/9/15-7/9/15 with PLSS 2.0 located inside a vacuum chamber. Test sequences included performance mapping of several components, carbon dioxide removal evaluations at simulated intravehicular activity (IVA) conditions, a regulator pressure schedule assessment, and culminated with 25 simulated extravehicular activities (EVAs). During the unmanned vacuum environment test series, PLSS 2.0 accumulated 378 hours of integrated testing including 291 hours of operation in a vacuum environment and 199 hours of simulated EVA time. The PLSS prototype performed nominally throughout the test series, with two notable exceptions including a pump failure and a Spacesuit Water Membrane Evaporator (SWME) leak, for which post-test failure investigations were performed. In addition to generating an extensive database of PLSS 2.0 performance data, achievements included requirements and

  7. Planetary Rings

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  8. The Saturn Ring Observer: In situ studies of planetary rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; Tiscareno, M. S.; Spilker, L. J.

    2010-12-01

    As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in a circular orbit above the ring plane: the Saturn Ring Observer. The technical findings and background are discussed in a companion poster by T. R. Spilker et al. Here we outline the science goals of such a mission. Most of the fundamental interactions in planetary rings occur on spatial scales that are unresolved by flyby or orbiter spacecraft. Typical particle sizes in the rings of Saturn are in the 1 cm - 10 m range, and average interparticle spacings are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 - 10 m, which implies a velocity dispersion of only a few mm/sec. Theories of ring structure and evolution depend on the unknown characteristics of interparticle collisions and on the size distribution of the ring particles. The SRO could provide direct measurements of both the coefficient of restitution -- by monitoring individual collisions -- and the particles’ velocity dispersion. High-resolution observations of individual ring particles should also permit estimates of their spin states. Numerical simulations of Saturn’s rings incorporating both collisions and self-gravity predict that the ring particles are not uniformly distributed, but are instead clustered into elongated structures referred to as “self-gravity wakes”, which are continually created and destroyed on an orbital timescale. Theory indicates that the average separation between wakes in the A ring is of order 30-100 m. Direct imaging of self-gravity wakes, including their formation and subsequent dissolution, would provide critical validation of these models. Other

  9. The design improvement of horizontal stripline kicker in TPS storage ring

    NASA Astrophysics Data System (ADS)

    Chou, P. J.; Chan, C. K.; Chang, C. C.; Hsu, K. T.; Hu, K. H.; Kuan, C. K.; Sheng, I. C.

    2017-07-01

    We plan to replace the existing horizontal stripline kicker of the transverse feedback system with an improved design. Large reflected power was observed at the downstream port of stripline kicker driven by the feedback amplifier. A rapid surge of vacuum pressure was observed when we tested the high current operation in TPS storage ring in April 2016. A burned feedthrough of the horizontal stripline kicker was discovered during a maintenance shutdown. The improved design is targeted to reduce the reflection of driving power from feedback system and to reduce beam induced RF heating. This major modification of the design is described. The results of RF simulation performed with the electromagnetic code GdfidL are reported as well.

  10. Retention of Plasmodium falciparum ring-infected erythrocytes in the slow, open microcirculation of the human spleen.

    PubMed

    Safeukui, Innocent; Correas, Jean-Michel; Brousse, Valentine; Hirt, Déborah; Deplaine, Guillaume; Mulé, Sébastien; Lesurtel, Mickael; Goasguen, Nicolas; Sauvanet, Alain; Couvelard, Anne; Kerneis, Sophie; Khun, Huot; Vigan-Womas, Inès; Ottone, Catherine; Molina, Thierry Jo; Tréluyer, Jean-Marc; Mercereau-Puijalon, Odile; Milon, Geneviève; David, Peter H; Buffet, Pierre A

    2008-09-15

    The current paradigm in Plasmodium falciparum malaria pathogenesis states that young, ring-infected erythrocytes (rings) circulate in peripheral blood and that mature stages are sequestered in the vasculature, avoiding clearance by the spleen. Through ex vivo perfusion of human spleens, we examined the interaction of this unique blood-filtering organ with P falciparum-infected erythrocytes. As predicted, mature stages were retained. However, more than 50% of rings were also retained and accumulated upstream from endothelial sinus wall slits of the open, slow red pulp microcirculation. Ten percent of rings were retained at each spleen passage, a rate matching the proportion of blood flowing through the slow circulatory compartment established in parallel using spleen contrast-enhanced ultrasonography in healthy volunteers. Rings displayed a mildly but significantly reduced elongation index, consistent with a retention process, due to their altered mechanical properties. This raises the new paradigm of a heterogeneous ring population, the less deformable subset being retained in the spleen, thereby reducing the parasite biomass that will sequester in vital organs, influencing the risk of severe complications, such as cerebral malaria or severe anemia. Cryptic ring retention uncovers a new role for the spleen in the control of parasite density, opening novel intervention opportunities.

  11. Jupiter's Main Ring

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa. A faint mist of particles can be seen above and below the main rings; this vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic.

    Jupiter's main ring is a thin strand of material encircling the planet. The diffuse innermost boundary begins at approximately 123,000 km. The main ring's outer radius is found to be

  12. Improving Vacuum Cleaners

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Space Act Agreement between the Kirby company and Lewis Research Center, NASA technology was applied to a commercial vacuum cleaner product line. Kirby engineers were interested in advanced operational concepts, such as particle flow behavior and vibration, critical factors to improve vacuum cleaner performance. An evaluation of the company 1994 home care system, the Kirby G4, led to the refinement of the new G5 and future models. Under the cooperative agreement, Kirby had access to Lewis' holography equipment, which added insight into how long a vacuum cleaner fan would perform, as well as advanced computer software that can simulate the flow of air through fans. The collaboration resulted in several successes including fan blade redesign and continuing dialogue on how to improve air-flow traits in various nozzle designs.

  13. Jupiter's ring

    NASA Technical Reports Server (NTRS)

    1979-01-01

    First evidence of a ring around the planet Jupiter is seen in this photograph taken by Voyager 1 on March 4, 1979. The multiple exposure of the extremely thin faint ring appears as a broad light band crossing the center of the picture. The edge of the ring is 1,212,000 km from the spacecraft and 57,000 km from the visible cloud deck of Jupiter. The background stars look like broken hair pins because of spacecraft motion during the 11 minute 12 second exposure. The wavy motion of the star trails is due to the ultra-slow natural oscillation of the spacecraft (with a period of 78 seconds). The black dots are geometric calibration points in the camera. The ring thickness is estimated to be 30 km or less. The photograph was part of a sequence planned to search for such rings in Jupiter's equatorial plane. The ring has been invisible from Earth because of its thinness and its transparency when viewed at any angle except straight on. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

  14. The vertical structure of the F ring of Saturn from ring-plane crossings

    NASA Astrophysics Data System (ADS)

    Scharringhausen, Britt R.; Nicholson, Philip D.

    2013-11-01

    We present a photometric model of the rings of Saturn which includes the main rings and an F ring, inclined to the main rings, with a Gaussian vertical profile of optical depth. This model reproduces the asymmetry in brightness between the east and west ansae of the rings of Saturn that was observed by the Hubble Space Telescope (HST) within a few hours after the Earth ring-plane crossing (RPX) of 10 August 1995. The model shows that during this observation the inclined F ring unevenly blocked the east and west ansae of the main rings. The brightness asymmetry produced by the model is highly sensitive to the vertical thickness and radial optical depth of the F ring. The F-ring model that best matches the observations has a vertical full width at half maximum of 13 ± 7 km and an equivalent depth of 10 ± 4 km. The model also reproduces the shape of the HST profiles of ring brightness vs. distance from Saturn, both before and after the time of ring-plane crossing. Smaller asymmetries observed before the RPX, when the Earth was on the dark side of the rings, cannot be explained by blocking of the main rings by the F ring or vice versa and are probably instead due to the intrinsic longitudinal variation exhibited by the F ring.

  15. Forward modeling of tree-ring data: a case study with a global network

    NASA Astrophysics Data System (ADS)

    Breitenmoser, P. D.; Frank, D.; Brönnimann, S.

    2012-04-01

    Information derived from tree-rings is one of the most powerful tools presently available for studying past climatic variability as well as identifying fundamental relationships between tree-growth and climate. Climate reconstructions are typically performed by extending linear relationships, established during the overlapping period of instrumental and climate proxy archives into the past. Such analyses, however, are limited by methodological assumptions, including stationarity and linearity of the climate-proxy relationship. We investigate climate and tree-ring data using the Vaganov-Shashkin-Lite (VS-Lite) forward model of tree-ring width formation to examine the relations among actual tree growth and climate (as inferred from the simulated chronologies) to reconstruct past climate variability. The VS-lite model has been shown to produce skill comparable to that achieved using classical dendrochronological statistical modeling techniques when applied on simulations of a network of North American tree-ring chronologies. Although the detailed mechanistic processes such as photosynthesis, storage, or cell processes are not modeled directly, the net effect of the dominating nonlinear climatic controls on tree-growth are implemented into the model by the principle of limiting factors and threshold growth response functions. The VS-lite model requires as inputs only latitude, monthly mean temperature and monthly accumulated precipitation. Hence, this simple, process-based model enables ring-width simulation at any location where monthly climate records exist. In this study, we analyse the growth response of simulated tree-rings to monthly climate conditions obtained from the 20th century reanalysis project back to 1871. These simulated tree-ring chronologies are compared to the climate-driven variability in worldwide observed tree-ring chronologies from the International Tree Ring Database. Results point toward the suitability of the relationship among actual tree

  16. Switching Circuit for Shop Vacuum System

    NASA Technical Reports Server (NTRS)

    Burley, R. K.

    1987-01-01

    No internal connections to machine tools required. Switching circuit controls vacuum system draws debris from grinders and sanders in machine shop. Circuit automatically turns on vacuum system whenever at least one sander or grinder operating. Debris safely removed, even when operator neglects to turn on vacuum system manually. Pickup coils sense alternating magnetic fields just outside operating machines. Signal from any coil or combination of coils causes vacuum system to be turned on.

  17. Ring-diameter Ratios for Multi-ring Basins Average 2.0(0.5)D

    NASA Technical Reports Server (NTRS)

    Pike, R. J.; Spudis, P. D.

    1985-01-01

    The spacing of the concentric rings of planetary impact basins was studied. It is shown that a radial increment of x (sup 0.5) D, where x is about 2.0 and D = ring diameter, separates both (1) adjacent least-squares groups of rings and arcs of multi-ring basins on Mars, Mercury, and the Moon; and (2) adjacent rings of individual basins on the three planets. Statistics for ratios of ring diameters are presented, the first and most-applied parameter of ring spacing. It is found that ratios excluding rings flanking the main ring also have a mean spacing increment of about 2.0. Ratios including such rings, as for the least-squares groups, and (1) above, have a larger increment, averaging 2.1. The F-test indicates, that these spacings of basin ring locations, and mode of ring formation are controlled by the mechanics of the impact event itself, rather than by crustal properties.

  18. Vacuum Brazing of Accelerator Components

    NASA Astrophysics Data System (ADS)

    Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

    2012-11-01

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  19. DESY II, a new injector for the DESY storage rings PETRA and DORIS II

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hemmie, G.

    1983-08-01

    There is a proposal to build a new 9 GeV electron synchrotron as a dedicated injector for the storage rings DORIS and PETRA. This machine will be housed in the old DESY-tunnel side-by-side with the original DESY-synchrotron. It is characterized by a separated function lattice, a 12.5 Hz repetition frequency, an all-metal vacuum chamber and a high shunt impedance rf-system. After commissioning of this new machine in 1984, the old DESY-synchrotron could be converted into a dedicated proton-accelerator as part of the injection chain for HERA.

  20. Investigation of Dielectric Breakdown Characteristics for Double-break Vacuum Interrupter and Dielectric Breakdown Probability Distribution in Vacuum Interrupter

    NASA Astrophysics Data System (ADS)

    Shioiri, Tetsu; Asari, Naoki; Sato, Junichi; Sasage, Kosuke; Yokokura, Kunio; Homma, Mitsutaka; Suzuki, Katsumi

    To investigate the reliability of equipment of vacuum insulation, a study was carried out to clarify breakdown probability distributions in vacuum gap. Further, a double-break vacuum circuit breaker was investigated for breakdown probability distribution. The test results show that the breakdown probability distribution of the vacuum gap can be represented by a Weibull distribution using a location parameter, which shows the voltage that permits a zero breakdown probability. The location parameter obtained from Weibull plot depends on electrode area. The shape parameter obtained from Weibull plot of vacuum gap was 10∼14, and is constant irrespective non-uniform field factor. The breakdown probability distribution after no-load switching can be represented by Weibull distribution using a location parameter. The shape parameter after no-load switching was 6∼8.5, and is constant, irrespective of gap length. This indicates that the scatter of breakdown voltage was increased by no-load switching. If the vacuum circuit breaker uses a double break, breakdown probability at low voltage becomes lower than single-break probability. Although potential distribution is a concern in the double-break vacuum cuicuit breaker, its insulation reliability is better than that of the single-break vacuum interrupter even if the bias of the vacuum interrupter's sharing voltage is taken into account.

  1. Vacuum-insulated catalytic converter

    DOEpatents

    Benson, David K.

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  2. Vacuum-Induction, Vacuum-Arc, and Air-Induction Melting of a Complex Heat-Resistant Alloy

    NASA Technical Reports Server (NTRS)

    Decker, R. F.; Rowe, John P.; Freeman, J. W.

    1959-01-01

    The relative hot-workability and creep-rupture properties at 1600 F of a complex 55Ni-20Cr-15Co-4Mo-3Ti-3Al alloy were evaluated for vacuum-induction, vacuum-arc, and air-induction melting. A limited study of the role of oxygen and nitrogen and the structural effects in the alloy associated with the melting process was carried out. The results showed that the level of boron and/or zirconium was far more influential on properties than the melting method. Vacuum melting did reduce corner cracking and improve surface during hot-rolling. It also resulted in more uniform properties within heats. The creep-rupture properties were slightly superior in vacuum heats at low boron plus zirconium or in heats with zirconium. There was little advantage at high boron levels and air heats were superior at high levels of boron plus zirconium. Vacuum heats also had fewer oxide and carbonitride inclusions although this was a function of the opportunity for separation of the inclusions from high oxygen plus nitrogen heats. The removal of phosphorous by vacuum melting was not found to be related to properties. Oxygen plus nitrogen appeared to increase ductility in creep-rupture tests suggesting that vacuum melting removes unidentified elements detrimental to ductility. Oxides and carbonitrides in themselves did not initiate microcracks. Carbonitrides in the grain boundaries of air heats did initiate microcracks. The role of microcracking from this source and as a function of oxygen and nitrogen content was not clear. Oxygen and nitrogen did intensify corner cracking during hot-rolling but were not responsible for poor surface which resulted from rolling heats melted in air.

  3. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, A.; Divsalar, D.; Yao, K.

    2004-01-01

    In this paper we propose an innovative channel coding scheme called Accumulate Repeat Accumulate codes. This class of codes can be viewed as trubo-like codes, namely a double serial concatenation of a rate-1 accumulator as an outer code, a regular or irregular repetition as a middle code, and a punctured accumulator as an inner code.

  4. Jupiter's Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.

    A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest

  5. Saturn Ring

    NASA Image and Video Library

    2007-12-12

    Like Earth, Saturn has an invisible ring of energetic ions trapped in its magnetic field. This feature is known as a "ring current." This ring current has been imaged with a special camera on Cassini sensitive to energetic neutral atoms. This is a false color map of the intensity of the energetic neutral atoms emitted from the ring current through a processed called charged exchange. In this process a trapped energetic ion steals and electron from cold gas atoms and becomes neutral and escapes the magnetic field. The Cassini Magnetospheric Imaging Instrument's ion and neutral camera records the intensity of the escaping particles, which provides a map of the ring current. In this image, the colors represent the intensity of the neutral emission, which is a reflection of the trapped ions. This "ring" is much farther from Saturn (roughly five times farther) than Saturn's famous icy rings. Red in the image represents the higher intensity of the particles, while blue is less intense. Saturn's ring current had not been mapped before on a global scale, only "snippets" or areas were mapped previously but not in this detail. This instrument allows scientists to produce movies (see PIA10083) that show how this ring changes over time. These movies reveal a dynamic system, which is usually not as uniform as depicted in this image. The ring current is doughnut shaped but in some instances it appears as if someone took a bite out of it. This image was obtained on March 19, 2007, at a latitude of about 54.5 degrees and radial distance 1.5 million kilometres (920,000 miles). Saturn is at the center, and the dotted circles represent the orbits of the moon's Rhea and Titan. The Z axis points parallel to Saturn's spin axis, the X axis points roughly sunward in the sun-spin axis plane, and the Y axis completes the system, pointing roughly toward dusk. The ion and neutral camera's field of view is marked by the white line and accounts for the cut-off of the image on the left. The

  6. Jupiter Ring

    NASA Image and Video Library

    2000-03-23

    First evidence of a ring around the planet Jupiter is seen in this photograph taken by Voyager 1 on March 4, 1979. The multiple exposure of the extremely thin faint ring appears as a broad light band crossing the center of the picture. The edge of the ring is 1,212,000 km from the spacecraft and 57,000 km from the visible cloud deck of Jupiter. The background stars look like broken hair pins because of spacecraft motion during the 11 minute 12 second exposure. The wavy motion of the star trails is due to the ultra-slow natural oscillation of the spacecraft (with a period of 78 seconds). The black dots are geometric calibration points in the camera. The ring thickness is estimated to be 30 km or less. The photograph was part of a sequence planned to search for such rings in Jupiter's equatorial plane. The ring has been invisible from Earth because of its thinness and its transparency when viewed at any angle except straight on. JPL manages and controls the Voyager Project for NASA's Office of Space Science. http://photojournal.jpl.nasa.gov/catalog/PIA02251

  7. Wireless Integrated Microelectronic Vacuum Sensor System

    NASA Technical Reports Server (NTRS)

    Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

    2013-01-01

    NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum

  8. Topological ring currents in the "empty" ring of benzo-annelated perylenes.

    PubMed

    Dickens, Timothy K; Mallion, Roger B

    2011-01-27

    Cyclic conjugation in benzo-annelated perylenes is examined by means of the topological π-electron ring currents calculated for each of their constituent rings, in a study that is an exact analogy of a recent investigation by Gutman et al. based on energy-effect values for the corresponding rings in each of these structures. "Classical" approaches, such as Kekulé structures, Clar "sextet" formulas, and circuits of conjugation, predict that the central ring in perylene is "empty" and thus contributes negligibly to cyclic conjugation. However, conclusions from the present calculations of topological ring currents agree remarkably with those arising from the earlier study involving energy-effect values in that, contrary to what would be predicted from the classical approaches, rings annelated in an angular fashion relative to the central ring of these perylene structures materially increase the extent of that ring's involvement in cyclic conjugation. It is suggested that such close quantitative agreement between the predictions of these two superficially very different indices (energy effect and topological ring current) might be due to the fact that, ultimately, both depend, albeit in ostensibly quite different ways, only on an adjacency matrix that contains information about the carbon-carbon connectivity of the conjugated system in question.

  9. Running vacuum cosmological models: linear scalar perturbations

    NASA Astrophysics Data System (ADS)

    Perico, E. L. D.; Tamayo, D. A.

    2017-08-01

    In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ(H2) or Λ(R). Such models assume an equation of state for the vacuum given by bar PΛ = - bar rhoΛ, relating its background pressure bar PΛ with its mean energy density bar rhoΛ ≡ Λ/8πG. This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interaction between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely bar rhoΛ = Σibar rhoΛi. Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ(H2) scenario the vacuum is coupled with every matter component, whereas the Λ(R) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.

  10. A correlative comparison of the ring current and auroral electrojects usig geomagnetic indices

    NASA Technical Reports Server (NTRS)

    Cade, W. B., III; Sojka, J. J.; Zhu, L.

    1995-01-01

    From a study of the 21 largest geomagnetic storms during solar cycle 21, a strong correlation is established between the ring current index Dst and the time-weighted accumulation of the 1-hour auroral electrojets indices, AE and AL. The time-weighted accumulation corresponds to convolution of the auroral electrojet indices with an exponential weighting function with an e-folding time of 9.4 hours. The weighted indices AE(sub w) and AL(sub w) have correltation coefficients against Dst ranging between 0.8 and 0.95 for 20 of the 21 storms. Correlation over the entire solar cycle 21 database is also strong but not as strong as for an individual storm. A set of simple Dst prediction functions provide a first approximation of the inferred dependence, but the specific functional relationship of Dst (AL(sub w)) or Dst (AL(sub w)) varies from one storm to the next in a systematic way. This variation reveals a missing parametric dependence in the transfer function. However, our results indicate that auroral electroject indices are potentially useful for predicting storm time enhancements of ring current intensity with a few hours lead time.

  11. An efficient, movable single-particle detector for use in cryogenic ultra-high vacuum environments.

    PubMed

    Spruck, Kaija; Becker, Arno; Fellenberger, Florian; Grieser, Manfred; von Hahn, Robert; Klinkhamer, Vincent; Novotný, Oldřich; Schippers, Stefan; Vogel, Stephen; Wolf, Andreas; Krantz, Claude

    2015-02-01

    A compact, highly efficient single-particle counting detector for ions of keV/u kinetic energy, movable by a long-stroke mechanical translation stage, has been developed at the Max-Planck-Institut für Kernphysik (Max Planck Institute for Nuclear Physics, MPIK). Both, detector and translation mechanics, can operate at ambient temperatures down to ∼10 K and consist fully of ultra-high vacuum compatible, high-temperature bakeable, and non-magnetic materials. The set-up is designed to meet the technical demands of MPIK's Cryogenic Storage Ring. We present a series of functional tests that demonstrate full suitability for this application and characterise the set-up with regard to its particle detection efficiency.

  12. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  13. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain...

  14. Vacuum Technology Considerations For Mass Metrology

    PubMed Central

    Abbott, Patrick J.; Jabour, Zeina J.

    2011-01-01

    Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

  15. Oxygen Abundances in the Rings of Polar-Ring Galaxies

    NASA Astrophysics Data System (ADS)

    Radtke, I. R.; Eskridge, P. B.; Pogge, R. W.

    2003-05-01

    Polar ring galaxies (PRGs) are typically early-type (S0 or E) galaxies surrounded by rings of gas, dust, and stars orbiting nearly perpendicular to the principle plane of the host galaxy (Whitmore et al. 1990 AJ 100 1489). Given that PRGs have two separate, perpendicular axes of rotation, it is clear on dynamical grounds that PRGs are the products of merger events between two galaxies, but are observed in a state where two distinct kinematic and morphological structures are still apparent. As such, they present a unique opportunity to study merger events in systems where the debris is not confused with material from the host. Our understanding of the relative importance of polar ring systems in the overall process of galaxy evolution is confounded by our lack of knowledge regarding the typical lifetimes and evolutionary histories of polar rings. A crucial factor for understanding the formation and evolution of PRGs is information regarding the elemental abundances of the ring material. Polar rings are typically rich in {\\protectH 2} regions. Optical spectroscopy of these {\\protectH 2} regions can tell us their density, temperature, and oxygen abundance. Our earlier work (Eskridge & Pogge 1997 ApJ 486 259) revealed roughly Solar oxygen abundances for {\\protectH 2} regions in the polar ring of NGC 2685. We have extended this project, and now have spectra for six PRGs. Analysis of the data for II Zw 73 and UGC 7576 reveal the polar rings of these galaxies to have {\\protectH 2} region oxygen abundances in the range 0.3 to 0.6 Solar, substantially less than found for NGC 2685. Abundances in this range are much easier to explain with conventional models of chemical enrichment and polar ring formation. We shall present results for our full sample. Taken as a whole, this sample will provide a clear foundation for the typical chemical enrichment patterns in polar rings, and thus provide a clearer understanding of the formation and evolution of these curious objects. We

  16. Saturn's F-Ring

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This narrow-angle camera image of Saturn's F Ring was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained ring shown here indicate that the ring is less uniform in makeup than the larger rings. JPL managed the Voyager Project for NASA's Office of Space Science

  17. Gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

    NASA Astrophysics Data System (ADS)

    Dhuley, Ram C.

    This dissertation describes the propagation of near atmospheric nitrogen gas that rushes into a liquid helium cooled vacuum tube after the tube suddenly loses vacuum. The loss-of-vacuum scenario resembles accidental venting of atmospheric air to the beam-line of a superconducting radio frequency particle accelerator and is investigated to understand how in the presence of condensation, the in-flowing air will propagate in such geometry. In a series of controlled experiments, room temperature nitrogen gas (a substitute for air) at a variety of mass flow rates was vented to a high vacuum tube immersed in a bath of liquid helium. Pressure probes and thermometers installed on the tube along its length measured respectively the tube pressure and tube wall temperature rise due to gas flooding and condensation. At high mass in-flow rates a gas front propagated down the vacuum tube but with a continuously decreasing speed. Regression analysis of the measured front arrival times indicates that the speed decreases nearly exponentially with the travel length. At low enough mass in-flow rates, no front propagated in the vacuum tube. Instead, the in-flowing gas steadily condensed over a short section of the tube near its entrance and the front appeared to `freeze-out'. An analytical expression is derived for gas front propagation speed in a vacuum tube in the presence of condensation. The analytical model qualitatively explains the front deceleration and flow freeze-out. The model is then simplified and supplemented with condensation heat/mass transfer data to again find the front to decelerate exponentially while going away from the tube entrance. Within the experimental and procedural uncertainty, the exponential decay length-scales obtained from the front arrival time regression and from the simplified model agree.

  18. Developing a vacuum cooking equipment prototype to produce strawberry jam and optimization of vacuum cooking conditions.

    PubMed

    Okut, Dilara; Devseren, Esra; Koç, Mehmet; Ocak, Özgül Özdestan; Karataş, Haluk; Kaymak-Ertekin, Figen

    2018-01-01

    Purpose of this study was to develop prototype cooking equipment that can work at reduced pressure and to evaluate its performance for production of strawberry jam. The effect of vacuum cooking conditions on color soluble solid content, reducing sugars total sugars HMF and sensory properties were investigated. Also, the optimum vacuum cooking conditions for strawberry jam were optimized for Composite Rotatable Design. The optimum cooking temperature and time were determined targeting maximum soluble solid content and sensory attributes (consistency) and minimum Hue value and HMF content. The optimum vacuum cooking conditions determined were 74.4 °C temperature and 19.8 time. The soluble solid content strawberry jam made by vacuum process were similar to those prepared by traditional method. HMF contents of jams produced with vacuum cooking method were well within limit of standards.

  19. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.

    2001-11-01

    A revolution in the studies in planetary rings studies occurred in the period 1977--1981, with the serendipitous discovery of the narrow, dark rings of Uranus, the first Voyager images of the tenuous jovian ring system, and the many spectacular images returned during the twin Voyager flybys of Saturn. In subsequent years, ground-based stellar occultations, HST observations, and the Voyager flybys of Uranus (1986) and Neptune (1989), as well as a handful of Galileo images, provided much additional information. Along with the completely unsuspected wealth of detail these observations revealed came an unwelcome problem: are the rings ancient or are we privileged to live at a special time in history? The answer to this still-vexing question may lie in the complex gravitational interactions recent studies have revealed between the rings and their retinues of attendant satellites. Among the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the context of galactic disks), electromagnetic resonances, spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to collective instabilities, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto parent bodies. Perhaps most puzzling is Saturn's multi-stranded, clumpy F ring, which continues to defy a simple explanation 20 years after it was first glimpsed in grainy images taken by Pioneer 11. Voyager and HST images reveal a complex, probably chaotic, dynamical interaction between unseen parent bodies within this ring and its two shepherd satellites, Pandora and Prometheus. The work described here reflects contributions by Joe Burns, Jeff Cuzzi, Luke Dones, Dick French, Peter Goldreich, Colleen McGhee, Carolyn Porco, Mark Showalter, and Bruno Sicardy, as well as those of the author. This research has been supported by NASA's Planetary Geology and Geophysics program and the

  20. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a.... (b) Each vacuum air system line and fitting on the discharge side of the pump that might contain...

  1. The 3-D numerical simulation research of vacuum injector for linear induction accelerator

    NASA Astrophysics Data System (ADS)

    Liu, Dagang; Xie, Mengjun; Tang, Xinbing; Liao, Shuqing

    2017-01-01

    Simulation method for voltage in-feed and electron injection of vacuum injector is given, and verification of the simulated voltage and current is carried out. The numerical simulation for the magnetic field of solenoid is implemented, and a comparative analysis is conducted between the simulation results and experimental results. A semi-implicit difference algorithm is adopted to suppress the numerical noise, and a parallel acceleration algorithm is used for increasing the computation speed. The RMS emittance calculation method of the beam envelope equations is analyzed. In addition, the simulated results of RMS emittance are compared with the experimental data. Finally, influences of the ferromagnetic rings on the radial and axial magnetic fields of solenoid as well as the emittance of beam are studied.

  2. Vacuum status-display and sector-conditioning programs

    NASA Astrophysics Data System (ADS)

    Skelly, J.; Yen, S.

    1990-08-01

    Two programs have been developed for observation and control of the AGS vacuum system, which include the following notable features: (1) they incorporate a graphical user interface and (2) they are driven by a relational database which describes the vacuum system. The vacuum system comprises some 440 devices organized into 28 vacuum sectors. The status-display program invites menu selection of a sector, interrogates the relational database for relevant vacuum devices, acquires live readbacks and posts a graphical display of their status. The sector-conditioning program likewise invites sector selection, produces the same status display and also implements process control logic on the sector devices to pump the sector down from atmospheric pressure to high vacuum over a period extending several hours. As additional devices are installed in the vacuum system, the devices are added to the relational database; these programs then automatically include the new devices.

  3. A new ring-shape high-temperature superconducting trapped-field magnet

    NASA Astrophysics Data System (ADS)

    Sheng, Jie; Zhang, Min; Wang, Yawei; Li, Xiaojian; Patel, Jay; Yuan, Weijia

    2017-09-01

    This paper presents a new trapped-field magnet made of second-generation high-temperature superconducting (2G HTS) rings. This so-called ring-shape 2G HTS magnet has the potential to provide much stronger magnetic fields relative to existing permanent magnets. Compared to existing 2G HTS trapped- field magnets, e.g. 2G HTS bulks and stacks, this new ring-shape 2G HTS magnet is more flexible in size and can be made into magnets with large dimensions for industrial applications. Effective magnetization is the key to being able to use trapped-field magnets. Therefore, this paper focuses on the magnetization mechanism of this new magnet using both experimental and numerical methods. Unique features have been identified and quantified for this new type of HTS magnet in the field cooling and zero field cooling process. The magnetization mechanism can be understood by the interaction between shielding currents and the penetration of external magnetic fields. An accumulation in the trapped field was observed by using multiple pulse field cooling. Three types of demagnetization were studied to measure the trapped-field decay for practical applications. Our results show that this new ring-shape HTS magnet is very promising in the trapping of a high magnetic field. As a super-permanent magnet, it will have a significant impact on large-scale industrial applications, e.g. the development of HTS machines with a very high power density and HTS magnetic resonance imaging devices.

  4. Mucinous colorectal adenocarcinoma with signet-ring cells: immunohistochemical and ultrastructural study.

    PubMed

    Seretis, E; Konstantinidou, A; Arnogiannakis, N; Xinopoulos, D; Voloudakis-Baltatzis, I E

    2010-12-01

    A primary mucinous colorectal adenocarcinoma tissue with signet-ring cells, as revealed after histological evaluation, was examined ultrastructurally. The authors also analyzed the immunohistochemical data of the tissue for serotonin, vasoactive intestinal polypeptide (VIP), bombesin, somatostatin, and glucagon, using the peroxidase anti-peroxidase (PAP) method and the immunogold labeling method for light and electron microscope, respectively. Electron microscopically mucinous adenocarcinoma was characterized by the formation of small lumen. Adenocarcinoma cells were full of mucous granules of varying electron density, providing a good environment for the tumor cells to grow. They also exhibited a significant loss of microvilli and intracytoplasmic junctions, which could allow the cells to disseminate. Signet-ring cells were located in the basal site of the ducts or in the lamina propria and appeared neoplastic, with mucin accumulation intracellularly and an eccentric crescent-shaped nucleus. The cytoplasmic organelles were decreased and at the periphery of the cell. The PAP method demonstrated that these cells were strongly positive for bombesin and also positive for vasointestinal polypeptide (VIP). The immunogold method detected bombesin immunoreactivity in the vacuoles as well as in other cytoplasmic membranes, whereas VIP was localized mainly in the plasma membrane. The location of signet-ring cells combined with the immunoreactivity for bombesin and VIP indicated that signet-ring cells were of neuroendocrine origin and probably dedifferentiated enterochromaffin-like endocrine cells. These findings have implications for understanding the biological behavior of these composite malignant tumors and could help in the knowledge of the origin of signet-ring cells.

  5. Working in a Vacuum

    ERIC Educational Resources Information Center

    Rathey, Allen

    2005-01-01

    In this article, the author discusses several myths about vacuum cleaners and offers tips on evaluating and purchasing this essential maintenance tool. These myths are: (1) Amps mean performance; (2) Everyone needs high-efficiency particulate air (HEPA): (3) Picking up a "bowling ball" shows cleaning power; (4) All vacuum bags are the same; (5)…

  6. The Ring Sculptor

    NASA Image and Video Library

    2006-09-08

    Prometheus zooms across the Cassini spacecraft field of view, attended by faint streamers and deep gores in the F ring. This movie sequence of five images shows the F ring shepherd moon shaping the ring inner edge

  7. Double-Vacuum-Bag Process for Making Resin-Matrix Composites

    NASA Technical Reports Server (NTRS)

    Bradford, Larry J.

    2007-01-01

    A double-vacuum-bag process has been devised as a superior alternative to a single-vacuum-bag process used heretofore in making laminated fiber-reinforced resin-matrix composite-material structural components. This process is applicable to broad classes of high-performance matrix resins including polyimides and phenolics that emit volatile compounds (solvents and volatile by-products of resin-curing chemical reactions) during processing. The superiority of the double-vacuum-bag process lies in enhanced management of the volatile compounds. Proper management of volatiles is necessary for making composite-material components of high quality: if not removed and otherwise properly managed, volatiles can accumulate in interior pockets as resins cure, thereby forming undesired voids in the finished products. The curing cycle for manufacturing a composite laminate containing a reactive resin matrix usually consists of a two-step ramp-and-hold temperature profile and an associated single-step pressure profile as shown in Figure 1. The lower-temperature ramp-and-hold step is known in the art as the B stage. During the B stage, prepregs are heated and volatiles are generated. Because pressure is not applied at this stage, volatiles are free to escape. Pressure is applied during the higher-temperature ramp-and-hold step to consolidate the laminate and impart desired physical properties to the resin matrix. The residual volatile content and fluidity of the resin at the beginning of application of consolidation pressure are determined by the temperature and time parameters of the B stage. Once the consolidation pressure is applied, residual volatiles are locked in. In order to produce a void-free, high-quality laminate, it is necessary to design the curing cycle to obtain the required residual fluidity and the required temperature at the time of application of the consolidation pressure.

  8. Nonperturbative vacuum polarization effects in two-dimensional supercritical Dirac-Coulomb system I. Vacuum charge density

    NASA Astrophysics Data System (ADS)

    Davydov, A.; Sveshnikov, K.; Voronina, Yu.

    2018-01-01

    Based on the original combination of analytical methods, computer algebra tools and numerical calculations, proposed recently in Refs. 1-3, the nonperturbative vacuum polarization effects in the 2+1D supercritical Dirac-Coulomb system with Z > Zcr,1 are explored. Both the vacuum charge density ρV P(r→) and vacuum energy ℰV P are considered. The main result of the work is that in the overcritical region ℰV P turns out to be a rapidly decreasing function ˜-ηeffZ3/R with ηeff > 0 and R being the size of the external Coulomb source. Due to a lot of details of calculation the whole work is divided into two parts I and II. In the present part I, we consider the evaluation and behavior of the vacuum density ρV P, which further is used in part II for evaluation of the vacuum energy, with emphasis on the renormalization, convergence of the partial expansion for ρV P and behavior of the integral induced charge QV P in the overcritical region.

  9. Mechanisms of ring chromosome formation, ring instability and clinical consequences.

    PubMed

    Guilherme, Roberta S; Meloni, Vera F Ayres; Kim, Chong A; Pellegrino, Renata; Takeno, Sylvia S; Spinner, Nancy B; Conlin, Laura K; Christofolini, Denise M; Kulikowski, Leslie D; Melaragno, Maria I

    2011-12-21

    The breakpoints and mechanisms of ring chromosome formation were studied and mapped in 14 patients. Several techniques were performed such as genome-wide array, MLPA (Multiplex Ligation-Dependent Probe Amplification) and FISH (Fluorescent in situ Hybridization). The ring chromosomes of patients I to XIV were determined to be, respectively: r(3)(p26.1q29), r(4)(p16.3q35.2), r(10)(p15.3q26.2), r(10)(p15.3q26.13), r(13)(p13q31.1), r(13)(p13q34), r(14)(p13q32.33), r(15)(p13q26.2), r(18)(p11.32q22.2), r(18)(p11.32q21.33), r(18)(p11.21q23), r(22)(p13q13.33), r(22)(p13q13.2), and r(22)(p13q13.2). These rings were found to have been formed by different mechanisms, such as: breaks in both chromosome arms followed by end-to-end reunion (patients IV, VIII, IX, XI, XIII and XIV); a break in one chromosome arm followed by fusion with the subtelomeric region of the other (patients I and II); a break in one chromosome arm followed by fusion with the opposite telomeric region (patients III and X); fusion of two subtelomeric regions (patient VII); and telomere-telomere fusion (patient XII). Thus, the r(14) and one r(22) can be considered complete rings, since there was no loss of relevant genetic material. Two patients (V and VI) with r(13) showed duplication along with terminal deletion of 13q, one of them proved to be inverted, a mechanism known as inv-dup-del. Ring instability was detected by ring loss and secondary aberrations in all but three patients, who presented stable ring chromosomes (II, XIII and XIV). We concluded that the clinical phenotype of patients with ring chromosomes may be related with different factors, including gene haploinsufficiency, gene duplications and ring instability. Epigenetic factors due to the circular architecture of ring chromosomes must also be considered, since even complete ring chromosomes can result in phenotypic alterations, as observed in our patients with complete r(14) and r(22).

  10. Night vision imaging system design, integration and verification in spacecraft vacuum thermal test

    NASA Astrophysics Data System (ADS)

    Shang, Yonghong; Wang, Jing; Gong, Zhe; Li, Xiyuan; Pei, Yifei; Bai, Tingzhu; Zhen, Haijing

    2015-08-01

    The purposes of spacecraft vacuum thermal test are to characterize the thermal control systems of the spacecraft and its component in its cruise configuration and to allow for early retirement of risks associated with mission-specific and novel thermal designs. The orbit heat flux is simulating by infrared lamp, infrared cage or electric heater. As infrared cage and electric heater do not emit visible light, or infrared lamp just emits limited visible light test, ordinary camera could not operate due to low luminous density in test. Moreover, some special instruments such as satellite-borne infrared sensors are sensitive to visible light and it couldn't compensate light during test. For improving the ability of fine monitoring on spacecraft and exhibition of test progress in condition of ultra-low luminous density, night vision imaging system is designed and integrated by BISEE. System is consist of high-gain image intensifier ICCD camera, assistant luminance system, glare protect system, thermal control system and computer control system. The multi-frame accumulation target detect technology is adopted for high quality image recognition in captive test. Optical system, mechanical system and electrical system are designed and integrated highly adaptable to vacuum environment. Molybdenum/Polyimide thin film electrical heater controls the temperature of ICCD camera. The results of performance validation test shown that system could operate under vacuum thermal environment of 1.33×10-3Pa vacuum degree and 100K shroud temperature in the space environment simulator, and its working temperature is maintains at 5° during two-day test. The night vision imaging system could obtain video quality of 60lp/mm resolving power.

  11. Nonperturbative vacuum polarization effects in two-dimensional supercritical Dirac-Coulomb system II. Vacuum energy

    NASA Astrophysics Data System (ADS)

    Davydov, A.; Sveshnikov, K.; Voronina, Yu.

    2018-01-01

    Nonperturbative vacuum polarization effects are explored for a supercritical Dirac-Coulomb system with Z > Zcr,1 in 2+1D, based on the original combination of analytical methods, computer algebra and numerical calculations, proposed recently in Refs. 1-3. Both the vacuum charge density ρV P(r→) and vacuum energy ℰV P are considered. Due to a lot of details of calculation the whole work is divided into two parts I and II. Taking account of results, obtained in the part I4 for ρV P, in the present part II, the evaluation of the vacuum energy ℰV P is investigated with emphasis on the renormalization and convergence of the partial expansion for ℰV P. It is shown that the renormalization via fermionic loop turns out to be the universal tool, which removes the divergence of the theory both in the purely perturbative and essentially nonperturbative regimes of the vacuum polarization. The main result of calculation is that for a wide range of the system parameters in the overcritical region ℰV P turns out to be a rapidly decreasing function ˜-ηeffZ3/R with ηeff > 0 and R being the size of the external Coulomb source. To the end the similarity in calculations of ℰV P in 2+1 and 3+1D is discussed, and qualitative arguments are presented in favor of the possibility for complete screening of the classical electrostatic energy of the Coulomb source by the vacuum polarization effects for Z ≫ Zcr,1 in 3+1D.

  12. Quantum vacuum noise in physics and cosmology.

    PubMed

    Davies, P. C. W.

    2001-09-01

    The concept of the vacuum in quantum field theory is a subtle one. Vacuum states have a rich and complex set of properties that produce distinctive, though usually exceedingly small, physical effects. Quantum vacuum noise is familiar in optical and electronic devices, but in this paper I wish to consider extending the discussion to systems in which gravitation, or large accelerations, are important. This leads to the prediction of vacuum friction: The quantum vacuum can act in a manner reminiscent of a viscous fluid. One result is that rapidly changing gravitational fields can create particles from the vacuum, and in turn the backreaction on the gravitational dynamics operates like a damping force. I consider such effects in early universe cosmology and the theory of quantum black holes, including the possibility that the large-scale structure of the universe might be produced by quantum vacuum noise in an early inflationary phase. I also discuss the curious phenomenon that an observer who accelerates through a quantum vacuum perceives a bath of thermal radiation closely analogous to Hawking radiation from black holes, even though an inertial observer registers no particles. The effects predicted raise very deep and unresolved issues about the nature of quantum particles, the role of the observer, and the relationship between the quantum vacuum and the concepts of information and entropy. (c) 2001 American Institute of Physics.

  13. Running vacuum cosmological models: linear scalar perturbations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Perico, E.L.D.; Tamayo, D.A., E-mail: elduartep@usp.br, E-mail: tamayo@if.usp.br

    In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ( H {sup 2}) or Λ( R ). Such models assume an equation of state for the vacuum given by P-bar {sub Λ} = - ρ-bar {sub Λ}, relating its background pressure P-bar {sub Λ} with its mean energy density ρ-bar {sub Λ} ≡ Λ/8π G . This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interactionmore » between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely ρ-bar {sub Λ} = Σ {sub i} ρ-bar {sub Λ} {sub i} . Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ( H {sup 2}) scenario the vacuum is coupled with every matter component, whereas the Λ( R ) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.« less

  14. So Long, C Ring

    NASA Image and Video Library

    2017-11-13

    Saturn's C ring is home to a surprisingly rich array of structures and textures. Much of the structure seen in the outer portions of Saturn's rings is the result of gravitational perturbations on ring particles by moons of Saturn. Such interactions are called resonances. However, scientists are not clear as to the origin of the structures seen in this image which has captured an inner ring region sparsely populated with particles, making interactions between ring particles rare, and with few satellite resonances. In this image, a bright and narrow ringlet located toward the outer edge of the C ring is flanked by two broader features called plateaus, each about 100 miles (160 kilometers) wide. Plateaus are unique to the C ring. Cassini data indicates that the plateaus do not necessarily contain more ring material than the C ring at large, but the ring particles in the plateaus may be smaller, enhancing their brightness. This view looks toward the sunlit side of the rings from about 53 degrees above the ring plane. The image was taken in green light with the Cassini spacecraft narrow-angle camera on Aug. 14, 2017. The view was acquired at a distance of approximately 117,000 miles (189,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 74 degrees. Image scale is 3,000 feet (1 kilometer) per pixel. The Cassini spacecraft ended its mission on Sept. 15, 2017. https://photojournal.jpl.nasa.gov/catalog/PIA21356

  15. Vacuum phonon tunneling.

    PubMed

    Altfeder, Igor; Voevodin, Andrey A; Roy, Ajit K

    2010-10-15

    Field-induced phonon tunneling, a previously unknown mechanism of interfacial thermal transport, has been revealed by ultrahigh vacuum inelastic scanning tunneling microscopy (STM). Using thermally broadened Fermi-Dirac distribution in the STM tip as in situ atomic-scale thermometer we found that thermal vibrations of the last tip atom are effectively transmitted to sample surface despite few angstroms wide vacuum gap. We show that phonon tunneling is driven by interfacial electric field and thermally vibrating image charges, and its rate is enhanced by surface electron-phonon interaction.

  16. 21 CFR 884.4340 - Fetal vacuum extractor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... means of a suction cup attached to the scalp and is powered by an external vacuum source. This generic type of device may include the cup, hosing, vacuum source, and vacuum control. (b) Classification...

  17. 21 CFR 884.4340 - Fetal vacuum extractor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... means of a suction cup attached to the scalp and is powered by an external vacuum source. This generic type of device may include the cup, hosing, vacuum source, and vacuum control. (b) Classification...

  18. Cold cathode vacuum gauging system

    DOEpatents

    Denny, Edward C.

    2004-03-09

    A vacuum gauging system of the cold cathode type is provided for measuring the pressure of a plurality of separate vacuum systems, such as in a gas centrifuge cascade. Each casing is fitted with a gauge tube assembly which communicates with the vacuum system in the centrifuge casing. Each gauge tube contains an anode which may be in the form of a slender rod or wire hoop and a cathode which may be formed by the wall of the gauge tube. The tube is provided with an insulated high voltage connector to the anode which has a terminal for external connection outside the vacuum casing. The tube extends from the casing so that a portable magnet assembly may be inserted about the tube to provide a magnetic field in the area between the anode and cathode necessary for pressure measurements in a cold cathode-type vacuum gauge arrangement. The portable magnetic assembly is provided with a connector which engages the external high voltage terminal for providing power to the anode within in the gauge tube. Measurement is made in the same manner as the prior cold cathode gauges in that the current through the anode to the cathode is measured as an indication of the pressure. By providing the portable magnetic assembly, a considerable savings in cost, installation, and maintenance of vacuum gauges for pressure measurement in a gas centrifuge cascade is realizable.

  19. Measurement of partial pressures in vacuum technology and vacuum physics

    NASA Technical Reports Server (NTRS)

    Huber, W. K.

    1986-01-01

    It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

  20. VACUUM TRAP AND VALVE COMBINATION

    DOEpatents

    Milleron, N.; Levenson, L.

    1963-02-19

    This patent relates to a vacuum trap and valve combination suitable for use in large ultra-high vacuum systems. The vacuum trap is a chamber having an inlet and outlet opening which may be made to communicate with a chamber to be evacuated and a diffusion pump, respectively. A valve is designed to hermeticaliy seal with inlet opening and, when opened, block the line-of- sight'' between the inlet and outlet openings, while allowing a large flow path between the opened vaive and the side walls of the trap. The interior of the trap and the side of the valve facing the inlet opening are covered with an impurity absorbent, such as Zeolite or activated aluminum. Besides the advantage of combining two components of a vacuum system into one, the present invention removes the need for a baffle between the pump and the chamber to be evacuated. In one use of a specific embodiment of this invention, the transmission probability was 45 and the partial pressure of the pump fluid vapor in the vacuum chamber was at least 100 times lower than its vapor pressure. (AEC)

  1. Ring faults and ring dikes around the Orientale basin on the Moon.

    PubMed

    Andrews-Hanna, Jeffrey C; Head, James W; Johnson, Brandon; Keane, James T; Kiefer, Walter S; McGovern, Patrick J; Neumann, Gregory A; Wieczorek, Mark A; Zuber, Maria T

    2018-08-01

    The Orientale basin is the youngest and best-preserved multiring impact basin on the Moon, having experienced only modest modification by subsequent impacts and volcanism. Orientale is often treated as the type example of a multiring basin, with three prominent rings outside of the inner depression: the Inner Rook Montes, the Outer Rook Montes, and the Cordillera. Here we use gravity data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission to reveal the subsurface structure of Orientale and its ring system. Gradients of the gravity data reveal a continuous ring dike intruded into the Outer Rook along the plane of the fault associated with the ring scarp. The volume of this ring dike is ~18 times greater than the volume of all extrusive mare deposits associated with the basin. The gravity gradient signature of the Cordillera ring indicates an offset along the fault across a shallow density interface, interpreted to be the base of the low-density ejecta blanket. Both gravity gradients and crustal thickness models indicate that the edge of the central cavity is shifted inward relative to the equivalent Inner Rook ring at the surface. Models of the deep basin structure show inflections along the crust-mantle interface at both the Outer Rook and Cordillera rings, indicating that the basin ring faults extend from the surface to at least the base of the crust. Fault dips range from 13-22° for the Cordillera fault in the northeastern quadrant, to 90° for the Outer Rook in the northwestern quadrant. The fault dips for both outer rings are lowest in the northeast, possibly due to the effects of either the direction of projectile motion or regional gradients in pre-impact crustal thickness. Similar ring dikes and ring faults are observed around the majority of lunar basins.

  2. Vascular ring

    MedlinePlus

    ... with aberrant subclavian and left ligamentum ateriosus; Congenital heart defect - vascular ring; Birth defect heart - vascular ring ... accounts for less than 1% of all congenital heart problems. The condition occurs as often in males ...

  3. Stable forming conditions and geometrical expansion of L-shape rings in ring rolling process

    NASA Astrophysics Data System (ADS)

    Quagliato, Luca; Berti, Guido A.; Kim, Dongwook; Kim, Naksoo

    2018-05-01

    Based on previous research results concerning the radial-axial ring rolling process of flat rings, this paper details an innovative approach for the determination of the stable forming conditions to successfully simulate the radial ring rolling process of L-shape profiled rings. In addition to that, an analytical model for the estimation of the geometrical expansion of L-shape rings from its initial flat ring preform is proposed and validated by comparing its results with those of numerical simulations. By utilizing the proposed approach, steady forming conditions could be achieved, granting a uniform expansion of the ring throughout the process for all of the six tested cases of rings having the final outer diameter of the flange ranging from 545mm and 1440mm. The validation of the proposed approach allowed concluding that the geometrical expansion of the ring, as estimated by the proposed analytical model, is in good agreement with the results of the numerical simulation, with a maximum error of 2.18%, in the estimation of the ring wall diameter, 1.42% of the ring flange diameter and 1.87% for the estimation of the inner diameter of the ring, respectively.

  4. Vacuum enhanced cutaneous biopsy instrument

    DOEpatents

    Collins, Joseph

    2000-01-01

    A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.

  5. Saturn’s Ring Rain: Initial Estimates of Ring Mass Loss Rates

    NASA Astrophysics Data System (ADS)

    Moore, Luke; O'Donoghue, J.; Mueller-Wodarg, I.; Mendillo, M.

    2013-10-01

    We estimate rates of mass loss from Saturn’s rings based on ionospheric model reproductions of derived H3+ column densities. On 17 April 2011 over two hours of near-infrared spectral data were obtained of Saturn using the Near InfraRed Spectrograph (NIRSPEC) instrument on the 10-m Keck II telescope. The intensity of two bright H3+ rotational-vibrational emission lines was visible from nearly pole to pole, allowing low-latitude ionospheric emissions to be studied for the first time, and revealing significant latitudinal structure, with local extrema in one hemisphere being mirrored at magnetically conjugate latitudes in the opposite hemisphere. Even more striking, those minima and maxima mapped to latitudes of increased or increased density in Saturn’s rings, implying a direct ring-atmosphere connection in which charged water group particles from the rings are guided by magnetic field lines as they “rain” down upon the atmosphere. Water products act to quench the local ionosphere, and therefore modify the observed H3+ densities. Using the Saturn Thermosphere Ionosphere Model (STIM), a 3-D model of Saturn’s upper atmosphere, we derive the rates of water influx required from the rings in order to reproduce the observed H3+ column densities. As a unique pair of conjugate latitudes map to a specific radial distance in the ring plane, the derived water influxes can equivalently be described as rates of ring mass erosion as a function of radial distance in the ring plane, and therefore also allow for an improved estimate of the lifetime of Saturn’s rings.

  6. Troubleshooting crude vacuum tower overhead ejector systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lines, J.R.; Frens, L.L.

    1995-03-01

    Routinely surveying tower overhead vacuum systems can improve performance and product quality. These vacuum systems normally provide reliable and consistent operation. However, process conditions, supplied utilities, corrosion, erosion and fouling all have an impact on ejector system performance. Refinery vacuum distillation towers use ejector systems to maintain tower top pressure and remove overhead gases. However, as with virtually all refinery equipment, performance may be affected by a number of variables. These variables may act independently or concurrently. It is important to understand basic operating principles of vacuum systems and how performance is affected by: utilities, corrosion and erosion, fouling, andmore » process conditions. Reputable vacuum-system suppliers have service engineers that will come to a refinery to survey the system and troubleshoot performance or offer suggestions for improvement. A skilled vacuum-system engineer may be needed to diagnose and remedy system problems. The affect of these variables on performance is discussed. A case history is described of a vacuum system on a crude tower in a South American refinery.« less

  7. The Enceladus Ring

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled)

    This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background.

    The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view.

    Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring.

    Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione.

    An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus.

    One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane.

    Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally

  8. PREFACE: Special section on vortex rings Special section on vortex rings

    NASA Astrophysics Data System (ADS)

    Fukumoto, Yasuhide

    2009-10-01

    This special section of Fluid Dynamics Research includes five articles on vortex rings in both classical and quantum fluids. The leading scientists of the field describe the trends in and the state-of-the-art development of experiments, theories and numerical simulations of vortex rings. The year 2008 was the 150th anniversary of 'vortex motion' since Hermann von Helmholtz opened up this field. In 1858, Helmholtz published a paper in Crelle's Journal which put forward the concept of 'vorticity' and made the first analysis of vortex motion. Fluid mechanics before that was limited to irrotational motion. In the absence of vorticity, the motion of an incompressible homogeneous fluid is virtually equivalent to a rigid-body motion in the sense that the fluid motion is determined once the boundary configuration is specified. Helmholtz proved, among other things, that, without viscosity, a vortex line is frozen into the fluid. This Helmholtz's law immediately implies the preservation of knots and links of vortex lines and its implication is enormous. One of the major trends of fluid mechanics since the latter half of the 20th century is to clarify the topological meaning of Helmholtz's law and to exploit it to develop theoretical and numerical methods to find the solutions of the Euler equations and to develop experimental techniques to gain an insight into fluid motion. Vortex rings are prominent coherent structures in a variety of fluid motions from the microscopic scale, through human and mesoscale to astrophysical scales, and have attracted people's interest. The late professor Philip G Saffman (1981) emphasized the significance of studies on vortex rings. One particular motion exemplifies the whole range of problems of vortex motion and is also a commonly known phenomenon, namely the vortex ring or smoke ring. Vortex rings are easily produced by dropping drops of one liquid into another, or by puffing fluid out of a hole, or by exhaling smoke if one has the skill

  9. Surface roughness of Saturn's rings and ring particles inferred from thermal phase curves

    NASA Astrophysics Data System (ADS)

    Morishima, Ryuji; Turner, Neal J.; Spilker, Linda

    2017-10-01

    We analyze thermal phase curves of all the main rings of Saturn (the A, B, C rings, and the Cassini division) measured by both the far-IR and mid-IR detectors of the Cassini Composite InfraRed Spectrometer (CIRS). All the rings show temperature increases toward zero phase angle, known as an opposition effect or thermal beaming. For the C ring and Cassini division, which have low optical depths, intra-particle shadowing is considered the dominant mechanism causing the effect. On the other hand, the phase curves of the optically thick B and A rings steepen significantly with decreasing absolute solar elevation angle from 21° to 14°, suggesting inter-particle shadowing plays an important role in these rings. We employ an analytic roughness model to estimate the degrees of surface roughness of the rings or ring particles. For optically thin rings, an isolated particle covered by spherical segment craters is employed while for the thick rings we approximate a packed particle layer as a slab covered by craters. The particles in the thin rings are found to have generally rough surfaces, except in the middle C ring. Across the C ring, the optical depth correlates with the degree of surface roughness. This may indicate that surface roughness comes mainly from particle clumping, while individual particles have rather smooth surfaces. For the optically thick rings, the surface roughness of the particle layer is found to be moderate. The modeled phase curves of optically thick rings are shallow if the phase angle change is primarily due to change of observer azimuthal angle. On the other hand, the phase curves are steep if the phase angle change is due to change of observer elevation angle, as inter-particle shadows become visible at higher observer elevation. In addition, the area of shadowed facets increases with decreasing solar elevation angle. These combined effects explain the large seasonal change of the phase curve steepness observed for the thick rings. The degrees

  10. Surface roughness of Saturn's rings and ring particles inferred from thermal phase curves

    NASA Astrophysics Data System (ADS)

    Morishima, Ryuji; Turner, Neal; Spilker, Linda

    2017-10-01

    We analyze thermal phase curves of all the main rings of Saturn (the A, B, C rings, and the Cassini division) measured by both the far-IR and mid-IR detectors of the Cassini Composite InfraRed Spectrometer (CIRS). All the rings show temperature increases toward zero phase angle, known as an opposition effect or thermal beaming. For the C ring and Cassini division, which have low optical depths, intra-particle shadowing is considered the dominant mechanism causing the effect. On the other hand, the phase curves of the optically thick B and A rings steepen significantly with decreasing absolute solar elevation angle from 21° to 14°, suggesting inter-particle shadowing plays an important role in these rings. We employ an analytic roughness model to estimate the degrees of surface roughness of the rings or ring particles. For optically thin rings, an isolated particle covered by spherical segment craters is employed while for the thick rings we approximate a packed particle layer as a slab covered by craters. The particles in the thin rings are found to have generally rough surfaces, except in the middle C ring. Across the C ring, the optical depth correlates with the degree of surface roughness. This may indicate that surface roughness comes mainly from particle clumping, while individual particles have rather smooth surfaces. For the optically thick rings, the surface roughness of the particle layer is found to be moderate. The modeled phase curves of optically thick rings are shallow if the phase angle change is primarily due to change of observer azimuthal angle. On the other hand, the phase curves are steep if the phase angle change is due to change of observer elevation angle, as inter-particle shadows become visible at higher observer elevation. In addition, the area of shadowed facets increases with decreasing solar elevation angle. These combined effects explain the large seasonal change of the phase curve steepness observed for the thick rings. The degrees

  11. Dusty D Ring

    NASA Image and Video Library

    2014-02-24

    Saturn D ring is easy to overlook since it trapped between the brighter C ring and the planet itself. In this view from NASA Cassini spacecraft, all that can be seen of the D ring is the faint and narrow arc as it stretches from top right of the ima

  12. Ring World

    NASA Image and Video Library

    2007-03-01

    Our robotic emissary, flying high above Saturn, captured this view of an alien copper-colored ring world. The overexposed planet has deliberately been removed to show the unlit rings alone, seen from an elevation of 60 degrees

  13. Vapor-barrier Vacuum Isolation System

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  14. Planetary rings: Structure and history

    NASA Astrophysics Data System (ADS)

    Esposito, L.

    The composition and structure of planetary rings provide the key evidence to understand their origin and evolution. Before the first space observations, we were able to maintain an idealized view of the rings around Saturn, the only known ring system at that time. Rings were then discovered around Jupiter, Uranus and Neptune. Saturn's F ring was discovered by Pioneer 11. Our ideal view of circular, planar, symmetric and unchanging rings was shattered by observations of inclined, eccentric rings, waves and wavy edges, and numerous processes acting at rates that give timescales much younger than the solar system. Moons within and near the rings sculpt them and are the likely progenitors of future rings. The moonlet lifetimes are much less than Saturn's age. The old idea of ancient rings gave rise to youthful rings, that are recently created by erosion and destruction of small nearby moons. Although this explanation may work well for most rings, Saturn's massive ring system provides a problem. It is extremely improbable that Saturn's rings were recently created by the destruction of a moon as large as Mimas, or even by the breakup of a large comet that passed too close to Saturn. The history of Saturn's rings has been a difficult problem, now made even more challenging by the close-up Cassini measurements. Cassini observations show unexpected ring variability in time and space. Time variations are seen in ring edges, in the thinner D and F rings, and in the neutral oxygen cloud, which outweighs the E ring in the same region around Saturn. The rings are inhomogeneous, with structures on all scales, sharp gradients and edges. Compositional gradients are sharper than expected, but nonetheless cross structural boundaries. This is evidence for ballistic transport that has not gone to completion. The autocovariance maximizes in the middle of the A ring, with smaller structure near the main rings' outer edge. Density wave locations have a fresher ice composition. The

  15. 7 CFR 58.423 - Cheese vacuumizing chamber.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....423 Cheese vacuumizing chamber. The vacuum chamber shall be satisfactorily constructed and maintained...

  16. 7 CFR 58.423 - Cheese vacuumizing chamber.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....423 Cheese vacuumizing chamber. The vacuum chamber shall be satisfactorily constructed and maintained...

  17. Ring King

    NASA Image and Video Library

    2014-08-18

    Saturn reigns supreme, encircled by its retinue of rings. Although all four giant planets have ring systems, Saturn's is by far the most massive and impressive. Scientists are trying to understand why by studying how the rings have formed and how they have evolved over time. Also seen in this image is Saturn's famous north polar vortex and hexagon. This view looks toward the sunlit side of the rings from about 37 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on May 4, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 2 million miles (3 million kilometers) from Saturn. Image scale is 110 miles (180 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18278

  18. A Pauson-Khand and ring-expansion approach to the aquariane ring system.

    PubMed

    Thornton, Paul D; Burnell, D Jean

    2006-07-20

    [Structure: see text] The carbocyclic ring system of the aquariolide diterpenes has been synthesized by two routes involving a diastereoselective Pauson-Khand reaction and subsequent ring expansion. In one route, a tetracyclic enone was elaborated to generate the nine-membered ring by Grob fragmentation. In the second approach, a spirocyclic tricycle underwent a facile anionic oxy-Cope rearrangement to complete the synthesis of the desired ring system.

  19. Engineering Matter Interactions Using Squeezed Vacuum

    NASA Astrophysics Data System (ADS)

    Zeytinoǧlu, Sina; Imamoǧlu, Ataç; Huber, Sebastian

    2017-04-01

    Virtually all interactions that are relevant for atomic and condensed matter physics are mediated by quantum fluctuations of the electromagnetic field vacuum. Consequently, controlling the vacuum fluctuations can be used to engineer the strength and the range of interactions. Recent experiments have used this premise to demonstrate novel quantum phases or entangling gates by embedding electric dipoles in photonic cavities or wave guides, which modify the electromagnetic fluctuations. Here, we show theoretically that the enhanced fluctuations in the antisqueezed quadrature of a squeezed vacuum state allow for engineering interactions between electric dipoles without the need for a photonic structure. Thus, the strength and range of the interactions can be engineered in a time-dependent way by changing the spatial profile of the squeezed vacuum in a traveling-wave geometry, which also allows the implementation of chiral dissipative interactions. Using experimentally realized squeezing parameters and including realistic losses, we predict single-atom cooperativities C of up to 10 for the squeezed-vacuum-enhanced interactions.

  20. SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K

    NASA Astrophysics Data System (ADS)

    DeGraff, B.; Howell, M.; Kim, S.; Neustadt, T.

    2017-12-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinney pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.

  1. Lightweight Vacuum Jacket for Cryogenic Insulation. Volume 1

    NASA Technical Reports Server (NTRS)

    Barclay, D. L.; Bell, J. E.; Brogren, E. W.; Straayer, J. W.

    1975-01-01

    The feasibility of producing a lightweight vacuum jacket using state-of-the-art technology and materials was examined. Design and analytical studies were made on a full-scale, orbital maneuvering system fuel tank. Preliminary design details were made for the tank assembly, including an optimized vacuum jacket and multilayer insulation system. A half-scale LH2 test model was designed and fabricated, and a force/stiffness proof test was conducted on the vacuum jacket. A vacuum leak rate of .000001 atmosphere ml of helium per second was measured, approximately 1500 hours of vacuum pressure were sustained, and 29 vacuum-pressure cycles were experienced prior to failure.

  2. Heating performances of a IC in-blanket ring array

    NASA Astrophysics Data System (ADS)

    Bosia, G.; Ragona, R.

    2015-12-01

    An important limiting factor to the use of ICRF as candidate heating method in a commercial reactor is due to the evanescence of the fast wave in vacuum and in most of the SOL layer, imposing proximity of the launching structure to the plasma boundary and causing, at the highest power level, high RF standing and DC rectified voltages at the plasma periphery, with frequent voltage breakdowns and enhanced local wall loading. In a previous work [1] the concept for an Ion Cyclotron Heating & Current Drive array (and using a different wave guide technology, a Lower Hybrid array) based on the use of periodic ring structure, integrated in the reactor blanket first wall and operating at high input power and low power density, was introduced. Based on the above concept, the heating performance of such array operating on a commercial fusion reactor is estimated.

  3. Heating performances of a IC in-blanket ring array

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bosia, G., E-mail: gbosia@to.infn.it; Ragona, R.

    2015-12-10

    An important limiting factor to the use of ICRF as candidate heating method in a commercial reactor is due to the evanescence of the fast wave in vacuum and in most of the SOL layer, imposing proximity of the launching structure to the plasma boundary and causing, at the highest power level, high RF standing and DC rectified voltages at the plasma periphery, with frequent voltage breakdowns and enhanced local wall loading. In a previous work [1] the concept for an Ion Cyclotron Heating & Current Drive array (and using a different wave guide technology, a Lower Hybrid array) basedmore » on the use of periodic ring structure, integrated in the reactor blanket first wall and operating at high input power and low power density, was introduced. Based on the above concept, the heating performance of such array operating on a commercial fusion reactor is estimated.« less

  4. 7 CFR 305.29 - Vacuum heat treatment schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Vacuum heat treatment schedule. 305.29 Section 305.29... SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Heat Treatments § 305.29 Vacuum heat treatment... vacuum at 8 hours. Maintain the vacuum until the end of the treatment. Gradually increase the temperature...

  5. Revealing the Self-Degradation Mechanisms in Methylammonium Lead Iodide Perovskites in Dark and Vacuum.

    PubMed

    Gunasekaran, Rajendra Kumar; Chinnadurai, Deviprasath; Selvaraj, Aravindha Raja; Rajendiran, Rajmohan; Senthil, Karuppanan; Prabakar, Kandasamy

    2018-06-19

    Organic-inorganic lead halide perovskite phases segregate (and their structures degrade) under illumination, exhibiting a poor stability with hysteresis and producing halide accumulation at the surface.In this work, we observed structural and interfacial dissociation in methylammonium lead iodide (CH 3 NH 3 PbI 3 ) perovskites even under dark and vacuum conditions. Here, we investigate the origin and consequences of self-degradation in CH 3 NH 3 PbI 3 perovskites stored in the dark under vacuum. Diffraction and photoelectron spectroscopic studies reveal the structural dissociation of perovskites into PbI 2 , which further dissociates into metallic lead (Pb 0 ) and I 2 - ions, collectively degrading the perovskite stability. Using TOF-SIMS analysis, AuI 2 - formation was directly observed, and it was found that an interplay between CH 3 NH 3 + , I 3 - , and mobile I - ions continuously regenerates more I 2 - ions, which diffuse to the surface even in the absence of light. Besides, halide diffusion causes a concentration gradient between Pb 0 and I 2 - and creates other ionic traps (PbI 2 - , PbI - ) that segregate as clusters at the perovskite/gold interface. A shift of the onset of the absorption band edge towards shorter wavelengths was also observed by absorption spectroscopy, indicating the formation of defect species upon aging in the dark under vacuum. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. [The evolution of vacuum extraction in obstetrics].

    PubMed

    Nikolov, A

    2010-01-01

    Vacuum extraction is one of the methods for assisted vaginal delivery. In this article the evolution of vacuum extraction in obstetrics is been discussed. Historical facts and data from the invention up to state-of-the-art vacuum systems in modern obstetrics are presented.

  7. Evaluation of a Prototype Hybrid Vacuum Pump to Provide Vacuum-Assisted Suspension for Above-Knee Prostheses

    PubMed Central

    Major, Matthew J.; Caldwell, Ryan; Fatone, Stefania

    2015-01-01

    Vacuum-assisted suspension (VAS) of prosthetic sockets utilizes a pump to evacuate air from between the prosthetic liner and socket, and are available as mechanical or electric systems. This technical note describes a hybrid pump that benefits from the advantages of mechanical and electric systems, and evaluates a prototype as proof-of-concept. Cyclical bench testing of the hybrid pump mechanical system was performed using a materials testing system to assess the relationship between compression cycles and vacuum pressure. Phase 1 in vivo testing of the hybrid pump was performed by an able-bodied individual using prosthesis simulator boots walking on a treadmill, and phase 2 involved an above-knee prosthesis user walking with the hybrid pump and a commercial electric pump for comparison. Bench testing of 300 compression cycles produced a maximum vacuum of 24 in-Hg. In vivo testing demonstrated that the hybrid pump continued to pull vacuum during walking, and as opposed to the commercial electric pump, did not require reactivation of the electric system during phase 2 testing. The novelty of the hybrid pump is that while the electric system provides rapid, initial vacuum suspension, the mechanical system provides continuous air evacuation while walking to maintain suspension without reactivation of the electric system, thereby allowing battery power to be reserved for monitoring vacuum levels. PMID:27462383

  8. O-Ring-Testing Fixture

    NASA Technical Reports Server (NTRS)

    Turner, James E.; Mccluney, D. Scott

    1991-01-01

    Fixture tests O-rings for sealing ability under dynamic conditions after extended periods of compression. Hydraulic cylinder moves plug in housing. Taper of 15 degrees on plug and cavity of housing ensures that gap created between O-ring under test and wall of cavity. Secondary O-rings above and below test ring maintain pressure applied to test ring. Evaluates effects of variety of parameters, including temperature, pressure, rate of pressurization, rate and magnitude of radial gap movement, and pretest compression time.

  9. 5-Aminolevulinic Acid Accumulation in a Cerebral Infarction Mimicking High-Grade Glioma.

    PubMed

    Behling, Felix; Hennersdorf, Florian; Bornemann, Antje; Tatagiba, Marcos; Skardelly, Marco

    2016-08-01

    5-Aminolevulinic acid (5-ALA) has become an integral part in the neurosurgical treatment of malignant glioma. Over time, several other tumor entities have been identified to metabolize 5-ALA and show a similar fluorescence pattern during surgical resection. This case report is the first description of 5-ALA accumulation in postischemic cerebral tissue. This evidence questions the assumption that 5-ALA accumulation in glioma is exclusively attributed to tumor infiltration. Instead, 5-ALA accumulation can also occur beyond the tumor borders and may be partially ascribed to inflammatory changes in the surrounding brain tissue. A 64-year old woman presented with episodes of apraxia and a ring-enhancing lesion in postcontrast T1-weighted magnetic resonance sequences suggestive of high grade glioma. Strong fluorescence was observed during 5-ALA-guided resection. However, although the frozen section was inconclusive, the final histopathologic examination revealed a stage II cerebral infarction. 5-ALA accumulation in postischemic cerebral tissue should be considered for intended supramarginal resections near eloquent brain regions. Therefore, sufficient preoperative imaging should regularly include magnetic resonance imaging spectroscopy and perfusion sequences to ascertain the proper diagnosis. Moreover, further research is warranted to determine the role of 5-ALA accumulation in postischemic and inflammatory brain tissue. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Nardo Ring, Italy

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Nardo Ring is a striking visual feature from space, and astronauts have photographed it several times. The Ring is a race car test track; it is 12.5 kilometers long and steeply banked to reduce the amount of active steering needed by drivers. The Nardo Ring lies in a remote area on the heel of Italy's 'boot,' 50 kilometers east of the naval port of Taranto. The Ring encompasses a number of active (green) and fallow (brown to dark brown) agricultural fields. In this zone of intensive agriculture, farmers gain access to their fields through the Ring via a series of underpasses. Winding features within the southern section of the Ring appear to be smaller, unused race tracks.

    The image covers an area of 18.8 x 16.4 km, was acquired on August 17. 2007, and is located at 49.3 degrees north latitude, 17.8 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. Gravitational collapse and the vacuum energy

    NASA Astrophysics Data System (ADS)

    Campos, M.

    2014-03-01

    To explain the accelerated expansion of the universe, models with interacting dark components (dark energy and dark matter) have been considered recently in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy of the all fields that fill the universe. As the other side of the same coin, the influence of the vacuum energy on the gravitational collapse is of great interest. We study such collapse adopting different parameterizations for the evolution of the vacuum energy. We discuss the homogeneous collapsing star fluid, that interacts with a vacuum energy component, using the stiff matter case as example. We conclude this work with a discussion of the Cahill-McVittie mass for the collapsed object.

  12. Gravitational baryogenesis in running vacuum models

    NASA Astrophysics Data System (ADS)

    Oikonomou, V. K.; Pan, Supriya; Nunes, Rafael C.

    2017-08-01

    We study the gravitational baryogenesis mechanism for generating baryon asymmetry in the context of running vacuum models. Regardless of whether these models can produce a viable cosmological evolution, we demonstrate that they produce a nonzero baryon-to-entropy ratio even if the universe is filled with conformal matter. This is a sound difference between the running vacuum gravitational baryogenesis and the Einstein-Hilbert one, since in the latter case, the predicted baryon-to-entropy ratio is zero. We consider two well known and most used running vacuum models and show that the resulting baryon-to-entropy ratio is compatible with the observational data. Moreover, we also show that the mechanism of gravitational baryogenesis may constrain the running vacuum models.

  13. Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.

    PubMed

    Zhou, Yihui; Wu, Wenbiao; Qiu, Keqiang

    2010-11-01

    In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. [Laser Induced Fluorescence Spectroscopic Analysis of Aromatics from One Ring to Four Rings].

    PubMed

    Zhang, Peng; Liu, Hai-feng; Yue, Zong-yu; Chen, Bei-ling; Yao, Ming-fa

    2015-06-01

    In order to distinguish small aromatics preferably, a Nd : YAG Laser was used to supply an excitation laser, which was adjusted to 0.085 J x cm(-2) at 266 nm. Benzene, toluene, naphthalene, phenanthrene, anthracene, pyrene and chrysene were used as the representative of different rings aromatics. The fluorescence emission spectra were researched for each aromatic hydrocarbon and mixtures by Laser induced fluorescence (LIF). Results showed that the rings number determined the fluorescence emission spectra, and the structure with same rings number did not affect the emission fluorescence spectrum ranges. This was due to the fact that the absorption efficiency difference at 266 nm resulted in that the fluorescence intensities of each aromatic hydrocarbon with same rings number were different and the fluorescence intensities difference were more apparently with aromatic ring number increasing. When the absorption efficiency was similar at 266 nm and the concentrations of each aromatic hydrocarbon were same, the fluorescence intensities were increased with aromatic ring number increasing. With aromatic ring number increasing, the fluorescence spectrum and emission peak wavelength were all red-shifted from ultraviolet to visible and the fluorescence spectrum range was also wider as the absorption efficiency was similar. The fluorescence emission spectra from one to four rings could be discriminated in the following wavelengths, 275 to 320 nm, 320 to 375 nm, 375 to 425 nm, 425 to 556 nm, respectively. It can be used for distinguish the type of the polycyclic aromatic hydrocarbons (PAHs) as it exists in single type. As PAHs are usually exist in a variety of different rings number at the same time, the results for each aromatic hydrocarbon may not apply to the aromatic hydrocarbon mixtures. For the aromatic hydrocarbon mixtures, results showed that the one- or two-ring PAHs in mixtures could not be detected by fluorescence as three- or four-ring PAHs existed in mixture

  15. Electric Propulsion Laboratory Vacuum Chamber

    NASA Image and Video Library

    1964-06-21

    Engineer Paul Reader and his colleagues take environmental measurements during testing of a 20-inch diameter ion engine in a vacuum tank at the Electric Propulsion Laboratory (EPL). Researchers at the Lewis Research Center were investigating the use of a permanent-magnet circuit to create the magnetic field required power electron bombardment ion engines. Typical ion engines use a solenoid coil to create this magnetic field. It was thought that the substitution of a permanent magnet would create a comparable magnetic field with a lower weight. Testing of the magnet system in the EPL vacuum tanks revealed no significant operational problems. Reader found the weight of the two systems was similar, but that the thruster’s efficiency increased with the magnet. The EPL contained a series of large vacuum tanks that could be used to simulate conditions in space. Large vacuum pumps reduced the internal air pressure, and a refrigeration system created the cryogenic temperatures found in space.

  16. Electrostatic forces in planetary rings

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.; Shan, Linhua; Havnes, O.

    1988-01-01

    The average charge on a particle in a particle-plasma cloud, the plasma potential inside the cloud, and the Coulomb force acting on the particle are calculated. The net repulsive electrostatic force on a particle depends on the plasma density, temperature, density of particles, particle size, and the gradient of the particle density. In a uniformly dense ring the electrostatic repulsion is zero. It is also shown that the electrostatic force acts like a pressure force, that even a collisionless ring can be stable against gravitational collapse, and that a finite ring thickness does not necessarily imply a finite velocity dispersion. A simple criterion for the importance of electrostatic forces in planetary rings is derived which involves the calculation of the vertical ring thickness which would result if only electrostatic repulsion were responsible for the finite ring thickness. Electrostatic forces are entirely negligible in the main rings of Saturn and the E and G rings. They may also be negligible in the F ring. However, the Uranian rings and Jupiter's ring seem to be very much influenced by electrostatic repulsion. In fact, electrostatic forces could support a Jovian ring which is an order of magnitude more dense than observed.

  17. Historical changes in lead concentrations in tree-rings of sycamore, oak and Scots pine in north-west England.

    PubMed

    Watmough, Shaun A; Hutchinson, Thomas C

    2002-07-03

    Lead concentrations in tree rings of sycamore (Acer pseudoplatanus L.), oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.) sampled at a parkland in north-west England were measured in wood formed since the mid-1800s. Concentrations of Pb in Scots pine and oak peaked in wood formed between 1900 and 1940, most likely because of Pb accumulation in heartwood, indicating that oak and Scots pine are unsuitable for monitoring temporal changes in Pb deposition at the study site. In contrast, Pb concentrations in sycamore, a species that has similar heartwood and sapwood chemistry, were relatively constant in wood formed between the mid-1800s and 1950. Lead concentrations decreased steadily in sycamore tree rings formed after the 1950s, and decreased more abruptly in wood formed after 1985. This sharp decrease in wood Pb cannot be due to decreases in soil Pb concentration. Stable Pb isotope analysis was used to further investigate Pb patterns in sycamore wood. Excess 206Pb/207Pb ratios in tree-rings of sycamore were relatively constant, approximately 1.17, in wood formed prior to the 1930s, but decreased steadily thereafter reaching a minimum value of approximately 1.16 in wood formed between 1975 and 1985 after which time 206Pb/207Pb ratios increased. This pattern is consistent with changes in Pb isotope ratios measured in peat, sediment and aerosol samples in the UK. However, the magnitude of the decrease in 206Pb/207Pb (largely due to gasoline Pb) is considerably lower than in other studies and our estimates indicate that less than 20% of the total Pb in sycamore wood measured since the mid-1800s is derived from gasoline emissions. A more likely explanation for the pattern of Pb observed in sycamore tree rings is that soil Pb accumulates within rings of the diffuse porous wood over a number of years. Such uptake patterns would result in lower Pb concentrations in the outer (more recently formed) tree rings, which coincide with recent reductions in Pb deposition

  18. Stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  19. Biomarkers and biometric measures of adherence to use of ARV-based vaginal rings.

    PubMed

    Stalter, Randy M; Moench, Thomas R; MacQueen, Kathleen M; Tolley, Elizabeth E; Owen, Derek H

    2016-01-01

    : intracellular drug levels, drug levels in hair, the accumulation of a vaginal analyte that diffuses into the ring, and the depletion of an intrinsic ring constituent. While some approaches show significant promise over others, it is recommended that a strategy of using complementary biometric and behavioural approaches be adopted to best understand participants' adherence to ARV-based ring products in clinical trials.

  20. How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?

    PubMed

    Mäthger, Lydia M; Bell, George R R; Kuzirian, Alan M; Allen, Justine J; Hanlon, Roger T

    2012-11-01

    The blue-ringed octopus (Hapalochlaena lunulata), one of the world's most venomous animals, has long captivated and endangered a large audience: children playing at the beach, divers turning over rocks, and biologists researching neurotoxins. These small animals spend much of their time in hiding, showing effective camouflage patterns. When disturbed, the octopus will flash around 60 iridescent blue rings and, when strongly harassed, bite and deliver a neurotoxin that can kill a human. Here, we describe the flashing mechanism and optical properties of these rings. The rings contain physiologically inert multilayer reflectors, arranged to reflect blue-green light in a broad viewing direction. Dark pigmented chromatophores are found beneath and around each ring to enhance contrast. No chromatophores are above the ring; this is unusual for cephalopods, which typically use chromatophores to cover or spectrally modify iridescence. The fast flashes are achieved using muscles under direct neural control. The ring is hidden by contraction of muscles above the iridophores; relaxation of these muscles and contraction of muscles outside the ring expose the iridescence. This mechanism of producing iridescent signals has not previously been reported in cephalopods and we suggest that it is an exceptionally effective way to create a fast and conspicuous warning display.

  1. Manipulating the Coffee-Ring Effect: Interactions at Work.

    PubMed

    Anyfantakis, Manos; Baigl, Damien

    2015-07-31

    The evaporation of a drop of colloidal suspension pinned on a substrate usually results in a ring of particles accumulated at the periphery of the initial drop. Intense research has been devoted to understanding, suppressing and ultimately controlling this so-called coffee-ring effect (CRE). Although the crucial role of flow patterns in the CRE has been thoroughly investigated, the effect of interactions on this phenomenon has been largely neglected. This Concept paper reviews recent works in this field and shows that the interactions of colloids with (and at) liquid-solid and liquid-gas interfaces as well as bulk particle-particle interactions drastically affect the morphology of the deposit. General rules are established to control the CRE by tuning these interactions, and guidelines for the rational physicochemical formulation of colloidal suspensions capable of depositing particles in desirable patterns are provided. This opens perspectives for the reliable control of the CRE in real-world formulations and creates new paradigms for flexible particle patterning at all kinds of interfaces as well for the exploitation of the CRE as a robust and inexpensive diagnostic tool. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The Crossings of Saturn Ring Plane by the Earth in 1995: Ring Thickness

    NASA Astrophysics Data System (ADS)

    Poulet, François; Sicardy, Bruno; Dumas, Christophe; Jorda, Laurent; Tiphène, Didier

    2000-05-01

    The crossings of Saturn's ring plane by Earth were observed in the near infrared on May 22 and August 10, 1995, from the 2.2-m telescope of the University of Hawaii, the 2-m telescope at Pic du Midi, France, and with the Adonis adaptive optics camera at the 3.6-m telescope of the European Southern Observatory in Chile. Images from the Hubble Space Telescope, obtained in August 1995, are also reanalyzed. The radial brightness profiles of the rings indicate that the outer and usually faint F ring dominates the edge-on brightness of the system, thus hiding the vertical structure of the main rings within a few hours around the ring plane crossing. The photometric behaviors of the A, B, and C rings and of the Cassini Division are analyzed, using a radiative transfer code which includes the illuminations by the Sun and by the planet. The F ring is modeled as a physically thick ribbon of height H, composed of large particles embedded in dust of fractional optical depth f. The observed profiles, combined with previous results, can be explained if the F ring is both optically thick ( radial optical depth ˜0.20) and physically thick ( H=21±4 km). We suggest that this vertical distribution results from the interactions between ring particles and shepherding satellites and/or from gravitational stirring by large bodies. The dust particles dominate the F ring's photometric behavior even in backscattered light ( f>0.80). Constraints on the particle properties of the other rings are also derived.

  3. LET-99 functions in the astral furrowing pathway, where it is required for myosin enrichment in the contractile ring

    PubMed Central

    Price, Kari L.; Rose, Lesilee S.

    2017-01-01

    The anaphase spindle determines the position of the cytokinesis furrow, such that the contractile ring assembles in an equatorial zone between the two spindle poles. Contractile ring formation is mediated by RhoA activation at the equator by the centralspindlin complex and midzone microtubules. Astral microtubules also inhibit RhoA accumulation at the poles. In the Caenorhabditis elegans one-cell embryo, the astral microtubule–dependent pathway requires anillin, NOP-1, and LET-99. LET-99 is well characterized for generating the asymmetric cortical localization of the Gα-dependent force-generating complex that positions the spindle during asymmetric division. However, whether the role of LET-99 in cytokinesis is specific to asymmetric division and whether it acts through Gα to promote furrowing are unclear. Here we show that LET-99 contributes to furrowing in both asymmetrically and symmetrically dividing cells, independent of its function in spindle positioning and Gα regulation. LET-99 acts in a pathway parallel to anillin and is required for myosin enrichment into the contractile ring. These and other results suggest a positive feedback model in which LET-99 localizes to the presumptive cleavage furrow in response to the spindle and myosin. Once positioned there, LET-99 enhances myosin accumulation to promote furrowing in both symmetrically and asymmetrically dividing cells. PMID:28701343

  4. Ion related problems for the XLS ring

    NASA Astrophysics Data System (ADS)

    Bozoki, Eva S.; Halama, Henry

    1991-10-01

    The electron beam in a storage ring collides with the residual gas in the vacuum chamber. As a consequence, low velocity positive ions are produced and trapped in the potential well of the electron beam. They perform stable or unstable oscillations around the beam under the repetitive Coulomb force of the bunches. If not cleared, the captured ions can lead to partial or total neutralization of the beam, causing both a decrease of lifetime and a change in the vertical tunes as well as an increase in the tune spread. It can also cause coherent and incoherent transverse instabilities. An electrostatic clearing electrodes system was designed to keep the neutralization below a desired limit. The location and the geometry of the clearing electrodes as well as the applied clearing voltage is based on the study of the ion production rate, longitudinal velocity of ions in field-free regions and in the dipoles, beam self-electric field, beam potential, critical mass for ion capture in the bunched beam and the bounce frequencies of the ions, tune shift and pressure rise due to trapped ions.

  5. Electrostatically Levitated Ring-Shaped Rotational-Gyro/Accelerometer

    NASA Astrophysics Data System (ADS)

    Murakoshi, Takao; Endo, Yasuo; Fukatsu, Keisuke; Nakamura, Sigeru; Esashi, Masayoshi

    2003-04-01

    This paper reports an electrostatically levitated inertia measurement system which is based on the principle of a rotational gyro. The device has several advantages: the levitation of the rotor in a vacuum eliminates mechanical friction resulting in high sensitivity; the position control for the levitation allows accelerations to be sensed in the tri-axis; and the fabrication of the device by a micromachining technique has the cost advantages afforded by miniaturization. Latest measurements yield a noise floor of the gyro and that of the accelerometer as low as 0.15 deg/h1/2 and 30 μG/Hz1/2, respectively. This performance is achieved by a new sensor design. To further improve of the previous device, a ring-shaped structure is designed and fabricated by deep reactive ion etching using inductively coupled plasma. The rotor levitation is performed with capacitive detection and electrostatic actuation. Multiaxis closed-loop control is realized by differential capacitance sensing and frequency multiplying. The rotation of the micro gyro is based on the principle of a planar variable capacitance motor.

  6. Luminescent Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This view shows the unlit face of Saturn's rings, visible via scattered and transmitted light. In these views, dark regions represent gaps and areas of higher particle densities, while brighter regions are filled with less dense concentrations of ring particles.

    The dim right side of the image contains nearly the entire C ring. The brighter region in the middle is the inner B ring, while the darkest part represents the dense outer B Ring. The Cassini Division and the innermost part of the A ring are at the upper-left.

    Saturn's shadow carves a dark triangle out of the lower right corner of this image.

    The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 8, 2005, at a distance of approximately 433,000 kilometers (269,000 miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

    For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

  7. A Photo-Favorskii Ring Contraction Reaction: The Effect of Ring Size

    PubMed Central

    Kammath, Viju Balachandran; Šolomek, Tomáš; Ngoy, Bokolombe Pitchou; Heger, Dominik; Klán, Petr; Rubina, Marina; Givens, Richard S.

    2012-01-01

    The effect of ring size on the photo-Favorskii induced ring-contraction reaction of the hydroxybenzocycloalkanonyl acetate and mesylate esters (7a–d, 8a–c) has provided new insight into the mechanism of the rearrangement. By monotonically decreasing the ring size in these cyclic derivatives, the increasing ring strain imposed on the formation of the elusive bicyclic spirocyclopropanone 20 results in a divergence away from rearrangement and toward solvolysis. Cycloalkanones of seven or eight carbons undergo a highly efficient photo-Favorskii rearrangement with ring contraction paralleling the photochemistry of p-hydroxyphenacyl esters. In contrast, the five-carbon ring does not rearrange but is diverted to the photosolvolysis channel avoiding the increased strain energy that would accompany the formation of the spirobicyclic ketone, the “Favorskii intermediate 20”. The six-carbon analogue demonstrates the bifurcation in reaction channels, yielding a solvent-sensitive mixture of both. Employing a combination of time-resolved absorption measurements, quantum yield determinations, isotopic labeling, and solvent variation studies coupled with theoretical treatment, a more comprehensive mechanistic description of the rearrangement has emerged. PMID:22686289

  8. Degradation of Phenolic Compounds and Ring Cleavage of Catechol by Phanerochaete chrysosporium

    PubMed Central

    Leatham, Gary F.; Crawford, R. L.; Kirk, T. Kent

    1983-01-01

    POL-88, a mutant of the white-rot fungus Phanerochaete chrysosporium, was selected for diminished phenol-oxidizing enzyme activity. A wide variety of phenolic compounds were degraded by ligninolytic cultures of this mutant. With several o-diphenolic substrates, degradation intermediates were produced that had UV spectra consistent with muconic acids. Extensive spectrophotometric and polarographic assays failed to detect classical ring-cleaving dioxygenases in cell homogenates or in extracts from ligninolytic cultures. Even so, a sensitive carrier-trapping assay showed that intact cultures degraded [U-14C]catechol to [14C]muconic acid, establishing the presence of a system capable of 1,2-intradiol fission. Significant accumulation of [14C]muconic acid into carrier occurred only when evolution of 14CO2 from [14C]catechol was inhibited by treating cultures with excess nutrient nitrogen (e.g., l-glutamic acid) or with cycloheximide. l-Glutamic acid is known from past work to repress the ligninolytic system in P. chrysosporium and to mimic the effect of cycloheximide. The results here indicate, therefore, that the enzyme system responsible for degrading ring-cleavage products to CO2 turns over faster than does the system responsible for ring cleavage. PMID:16346340

  9. Vacuum Energy and Inflation: 4. An Inflationary Universe

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2013-01-01

    This is the fourth paper in a series of four. The first paper in the series, "Vacuum Energy and Inflation: 1. A Liter of Vacuum Energy" [EJ1024183] discusses an example of vacuum energy. Vacuum energy is explained as an energy with a negative pressure whose energy density remains constant in an expanding space. Paper 2, "Vacuum…

  10. Earth: A Ringed Planet?

    NASA Astrophysics Data System (ADS)

    Hancock, L. O.; Povenmire, H.

    2010-12-01

    Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring

  11. Dynamics of the Uranian Rings

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  12. Accumulation of Carotenoids and Expression of Carotenoid Biosynthetic Genes during Maturation in Citrus Fruit1

    PubMed Central

    Kato, Masaya; Ikoma, Yoshinori; Matsumoto, Hikaru; Sugiura, Minoru; Hyodo, Hiroshi; Yano, Masamichi

    2004-01-01

    The relationship between carotenoid accumulation and the expression of carotenoid biosynthetic genes during fruit maturation was investigated in three citrus varieties, Satsuma mandarin (Citrus unshiu Marc.), Valencia orange (Citrus sinensis Osbeck), and Lisbon lemon (Citrus limon Burm.f.). We cloned the cDNAs for phytoene synthase (CitPSY), phytoene desaturase (CitPDS), ζ-carotene (car) desaturase (CitZDS), carotenoid isomerase (CitCRTISO), lycopene β-cyclase (CitLCYb), β-ring hydroxylase (CitHYb), zeaxanthin (zea) epoxidase (CitZEP), and lycopene ε-cyclase (CitLCYe) from Satsuma mandarin, which shared high identities in nucleotide sequences with Valencia orange, Lisbon lemon, and other plant species. With the transition of peel color from green to orange, the change from β,ε-carotenoid (α-car and lutein) accumulation to β,β-carotenoid (β-car, β-cryptoxanthin, zea, and violaxanthin) accumulation was observed in the flavedos of Satsuma mandarin and Valencia orange, accompanying the disappearance of CitLCYe transcripts and the increase in CitLCYb transcripts. Even in green fruit, high levels of β,ε-carotenoids and CitLCYe transcripts were not observed in the juice sacs. As fruit maturation progressed in Satsuma mandarin and Valencia orange, a simultaneous increase in the expression of genes (CitPSY, CitPDS, CitZDS, CitLCYb, CitHYb, and CitZEP) led to massive β,β-xanthophyll (β-cryptoxanthin, zea, and violaxanthin) accumulation in both the flavedo and juice sacs. The gene expression of CitCRTISO was kept low or decreased in the flavedo during massive β,β-xanthophyll accumulation. In the flavedo of Lisbon lemon and Satsuma mandarin, massive accumulation of phytoene was observed with a decrease in the transcript level for CitPDS. Thus, the carotenoid accumulation during citrus fruit maturation was highly regulated by the coordination of the expression among carotenoid biosynthetic genes. In this paper, the mechanism leading to diversity in

  13. First storage of ion beams in the Double Electrostatic Ion-Ring Experiment: DESIREE.

    PubMed

    Schmidt, H T; Thomas, R D; Gatchell, M; Rosén, S; Reinhed, P; Löfgren, P; Brännholm, L; Blom, M; Björkhage, M; Bäckström, E; Alexander, J D; Leontein, S; Hanstorp, D; Zettergren, H; Liljeby, L; Källberg, A; Simonsson, A; Hellberg, F; Mannervik, S; Larsson, M; Geppert, W D; Rensfelt, K G; Danared, H; Paál, A; Masuda, M; Halldén, P; Andler, G; Stockett, M H; Chen, T; Källersjö, G; Weimer, J; Hansen, K; Hartman, H; Cederquist, H

    2013-05-01

    We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C(n)(-), n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C2 (-) molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s ± 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10(-14) mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.

  14. 21 CFR 884.5070 - Vacuum abortion system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

  15. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

  16. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

  17. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

  18. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

  19. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve...

  20. 21 CFR 884.5070 - Vacuum abortion system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

  1. 21 CFR 884.5070 - Vacuum abortion system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

  2. 21 CFR 884.5070 - Vacuum abortion system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

  3. 21 CFR 884.5070 - Vacuum abortion system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vacuum abortion system. 884.5070 Section 884.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... § 884.5070 Vacuum abortion system. (a) Identification. A vacuum abortion system is a device designed to...

  4. The localized quantum vacuum field

    NASA Astrophysics Data System (ADS)

    Dragoman, D.

    2008-03-01

    A model for the localized quantum vacuum is proposed in which the zero-point energy (ZPE) of the quantum electromagnetic field originates in energy- and momentum-conserving transitions of material systems from their ground state to an unstable state with negative energy. These transitions are accompanied by emissions and re-absorptions of real photons, which generate a localized quantum vacuum in the neighborhood of material systems. The model could help resolve the cosmological paradox associated with the ZPE of electromagnetic fields, while reclaiming quantum effects associated with quantum vacuum such as the Casimir effect and the Lamb shift. It also offers a new insight into the Zitterbewegung of material particles.

  5. Relict slope rings and talus flatirons in the Colorado Piedmont: Origin, chronology and paleoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Francisco; Morgan, Matthew L.; Matthews, Vincent; Gutiérrez, Mateo; Jiménez-Moreno, Gonzalo

    2015-02-01

    In the Colorado Piedmont, talus flatiron chronosequences are associated with buttes that consist of erodible arkosic sandstone and resistant caprock. Following the removal of the caprock, some buttes evolve into crater-like relict slope rings resulting from the differential erosion of the soft bedrock in the core of the hills. These unique landforms are only documented in the Colorado Piedmont. Their development is attributed to the unusually high erodibility contrast between the low-cohesion sandy bedrock and the bouldery colluvial armor. The talus flatiron sequences and relict slope rings mapped in the three studied areas record alternating periods of accumulation and incision in the slopes that are likely controlled by changes in moisture availability and vegetation cover density. The obtained OSL dates place slope accumulation phases at > 124 ka, and ca. 73 ka, 50-40 ka, 15 ka, and 10-6 ka. A comparison of these geochronological data with paleoclimatic records from the region suggests that colluvium deposition occurred during periods of denser vegetation cover, which are controlled by climate changes. Further investigations, including additional and more accurate geochrological data from the relict slopes, will help to better understand the paleoclimatic significance of these largely unknown morphostratigraphic features.

  6. Uranus rings and two moons

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Voyager 2 has discovered two 'shepherd' satellites associated with the rings of Uranus. The two moons -- designated 1986U7 and 1986U8 -- are seen here on either side of the bright epsilon ring; all nine of the known Uranian rings are visible. The image was taken Jan. 21, 1986, at a distance of 4.1 million kilometers (2.5 million miles) and resolution of about 36 km (22 mi). The image was processed to enhance narrow features. The epsilon ring appears surrounded by a dark halo as a result of this processing; occasional blips seen on the ring are also artifacts. Lying inward from the epsilon ring are the delta, gamma and eta rings; then the beta and alpha rings; and finally the barely visible 4, 5 and 6 rings. The rings have been studied since their discovery in 1977, through observations of how they diminish the light of stars they pass in front of. This image is the first direct observation of all nine rings in reflected sunlight. They range in width from about 100 km (60 mi) at the widest part of the epsilon ring to only a few kilometers for most of the others. The discovery of the two ring moons 1986U7 and 1986U8 is a major advance in our understanding of the structure of the Uranian rings and is in good agreement with theoretical predictions of how these narrow rings are kept from spreading out. Based on likely surface brightness properties, the moons are of roughly 2O- and 3O-km diameter, respectively. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  7. Vacuum casting of thick polymeric films

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Moacanin, J.

    1979-01-01

    Bubble formation and layering, which often plague vacuum-evaporated films, are prevented by properly regulating process parameters. Vacuum casting may be applicable to forming thick films of other polymer/solvent solutions.

  8. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. [Doc. No...

  9. Ceramic vacuum tubes for geothermal well logging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kelly, R.D.

    1977-01-12

    The results of investigations carried out into the availability and suitability of ceramic vacuum tubes for the development of logging tools for geothermal wells are summarized. Design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes for application to the development of high temperature well logs are discussed. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data is presented in the appendix. (MHR)

  10. Compressed Air/Vacuum Transportation Techniques

    NASA Astrophysics Data System (ADS)

    Guha, Shyamal

    2011-03-01

    General theory of compressed air/vacuum transportation will be presented. In this transportation, a vehicle (such as an automobile or a rail car) is powered either by compressed air or by air at near vacuum pressure. Four version of such transportation is feasible. In all versions, a ``c-shaped'' plastic or ceramic pipe lies buried a few inches under the ground surface. This pipe carries compressed air or air at near vacuum pressure. In type I transportation, a vehicle draws compressed air (or vacuum) from this buried pipe. Using turbine or reciprocating air cylinder, mechanical power is generated from compressed air (or from vacuum). This mechanical power transferred to the wheels of an automobile (or a rail car) drives the vehicle. In type II-IV transportation techniques, a horizontal force is generated inside the plastic (or ceramic) pipe. A set of vertical and horizontal steel bars is used to transmit this force to the automobile on the road (or to a rail car on rail track). The proposed transportation system has following merits: virtually accident free; highly energy efficient; pollution free and it will not contribute to carbon dioxide emission. Some developmental work on this transportation will be needed before it can be used by the traveling public. The entire transportation system could be computer controlled.

  11. Tiny Mimas, Huge Rings

    NASA Image and Video Library

    2016-11-28

    Saturn's icy moon Mimas is dwarfed by the planet's enormous rings. Because Mimas (near lower left) appears tiny by comparison, it might seem that the rings would be far more massive, but this is not the case. Scientists think the rings are no more than a few times as massive as Mimas, or perhaps just a fraction of Mimas' mass. Cassini is expected to determine the mass of Saturn's rings to within just a few hundredths of Mimas' mass as the mission winds down by tracking radio signals from the spacecraft as it flies close to the rings. The rings, which are made of small, icy particles spread over a vast area, are extremely thin -- generally no thicker than the height of a house. Thus, despite their giant proportions, the rings contain a surprisingly small amount of material. Mimas is 246 miles (396 kilometers) wide. This view looks toward the sunlit side of the rings from about 6 degrees above the ring plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on July 21, 2016. The view was obtained at a distance of approximately 564,000 miles (907,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 31 degrees. Image scale is 34 miles (54 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20509

  12. Vacuum chamber-free centrifuge with magnetic bearings.

    PubMed

    Park, Cheol Hoon; Kim, Soohyun; Kim, Kyung-Soo

    2013-09-01

    Centrifuges are devices that separate particles of different densities and sizes through the application of a centrifugal force. If a centrifuge could be operated under atmospheric conditions, all vacuum-related components such as the vacuum chamber, vacuum pump, diffusion pump, and sealing could be removed from a conventional centrifuge system. The design and manufacturing procedure for centrifuges could then be greatly simplified to facilitate the production of lightweight centrifuge systems of smaller volume. Furthermore, the maintenance costs incurred owing to wear and tear due to conventional ball bearings would be eliminated. In this study, we describe a novel vacuum chamber-free centrifuge supported by magnetic bearings. We demonstrate the feasibility of the vacuum chamber-free centrifuge by presenting experimental results that verify its high-speed support capability and motoring power capacity.

  13. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1993-11-09

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of standard polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  14. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1995-03-07

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  15. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1993-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  16. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1995-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  17. On a suspected ring external to the visible rings of Saturn

    NASA Technical Reports Server (NTRS)

    Feibelman, W. A.; Beebe, R. F.; Smith, B. A.; Cook, A. F., II

    1974-01-01

    The reexamination of a photograph of Saturn taken on 15 November 1966 when the earth was nearly in the ring plane is investigated which indicates that ring material does exist outside the visible rings, extending to more than 6 Saturnian radii. The observed brightness in blue light was estimated per linear arc second, implying a normal optical thickness, for ice-covered particles.

  18. Cryogenic Insulation System for Soft Vacuum

    NASA Technical Reports Server (NTRS)

    Augustynowicz, S. D.; Fesmire, J. E.

    1999-01-01

    The development of a cryogenic insulation system for operation under soft vacuum is presented in this paper. Conventional insulation materials for cryogenic applications can be divided into three levels of thermal performance, in terms of apparent thermal conductivity [k-value in milliwatt per meter-kelvin (mW/m-K)]. System k-values below 0.1 can be achieved for multilayer insulation operating at a vacuum level below 1 x 10(exp -4) torr. For fiberglass or powder operating below 1 x 10(exp -3) torr, k-values of about 2 are obtained. For foam and other materials at ambient pressure, k-values around 30 are typical. New industry and aerospace applications require a versatile, robust, low-cost thermal insulation with performance in the intermediate range. The target for the new composite insulation system is a k-value below 4.8 mW/m-K (R-30) at a soft vacuum level (from 1 to 10 torr) and boundary temperatures of approximately 77 and 293 kelvin (K). Many combinations of radiation shields, spacers, and composite materials were tested from high vacuum to ambient pressure using cryostat boiloff methods. Significant improvement over conventional systems in the soft vacuum range was demonstrated. The new layered composite insulation system was also shown to provide key benefits for high vacuum applications as well.

  19. Vacuum-assisted venous return reduces blood usage.

    PubMed

    Banbury, Michael K; White, Jennifer A; Blackstone, Eugene H; Cosgrove, Delos M

    2003-09-01

    To determine whether vacuum-assisted venous return has clinical advantages over conventional gravity drainage apart from allowing the use of smaller cannulas and shorter tubing. A total of 150 valve operations were performed at our institution between February and July 1999 using vacuum-assisted venous return with small venous cannulas connected to short tubing. These were compared with (1) 83 valve operations performed between April 1997 and January 1998 using the initial version of vacuum-assisted venous return, and (2) 124 valve operations performed between January and April of 1997 using conventional gravity drainage. Priming volume, hematocrit value, red blood cell usage, and total blood product usage were compared multivariably. These comparisons were covariate and propensity adjusted for dissimilarities between the groups and confirmed by propensity-matched pairs analysis. Priming volume was 1.4 +/- 0.4 L for small-cannula vacuum-assisted venous return, 1.7 +/- 0.4 L for initial vacuum-assisted venous return, and 2.0 +/- 0.4 L for gravity drainage (P <.0001). Smaller priming resulted in higher hematocrit values both at the beginning of cardiopulmonary bypass (27% +/- 5% compared with 26% +/- 4% and 25% +/- 4%, respectively, P <.0001) and at the end (30% +/- 4% compared with 28% +/- 4% and 27% +/- 4%, respectively, P <.0001). Red cell transfusions were used in 17% of the patients having small-cannula vacuum-assisted venous return, 27% of the initial patients having vacuum-assisted venous return, and 37% of the patients having gravity drainage (P =.001); total blood product usage was 19%, 27%, and 39%, respectively (P =.002). Although ministernotomy also was associated with reduced blood product usage (P <.004), propensity matching on type of sternotomy confirmed the association of vacuum-assisted venous return with lowered blood product usage. Vacuum-assisted venous return results in (1) higher hematocrit values during cardiopulmonary bypass and (2) decreased

  20. Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

    NASA Astrophysics Data System (ADS)

    Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

    2015-12-01

    Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process.

  1. Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

    PubMed Central

    Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

    2015-01-01

    Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process. PMID:26643504

  2. Development of an Abort Gap Monitor for High-Energy Proton Rings

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beche, J.-F.; Byrd, J.; De Santis, S.

    2004-11-10

    The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the 'abort gap', and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider.« less

  3. Development of an abort gap monitor for high-energy proton rings

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beche, Jean-Francois; Byrd, John; De Santis, Stefano

    2004-05-03

    The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider« less

  4. Highly concentrated, ring-shaped phase conversion laser-induced breakdown spectroscopy technology for liquid sample analysis.

    PubMed

    Lin, Qingyu; Wei, Zhimei; Guo, Hongli; Wang, Shuai; Guo, Guangmeng; Zhang, Zhi; Duan, Yixiang

    2017-06-10

    A highly concentrated, ring-shaped phase conversion (RSPC) method was developed for liquid sample analysis using the laser-induced breakdown spectroscopy (LIBS) technique. In this work, test samples were prepared by mixing the metal particles with polyvinyl alcohol (PVA) supporter in liquid phase. With heat, the PVA solution solidified inside a modified glass petri dish, forming a metal-enriched polymer ring film. Distinguished from other traditional liquid-to-solid conversing methods, the proposed new method takes advantage of enhanced homogeneity for the target elements inside the ring film. The modified glass petri dish was used to control the ring-shaped concentration. Due to the specially designed circular groove at the bottom of this dish, where the PVA solution and liquid sample mixture accumulated, the target elements were concentrated in this small ring, which is beneficial for enhancing and stabilizing the plasma signals compared to the direct liquid sample analysis using LIBS. The limits of detection for Ag, Cu, Cr, and Ba obtained with the RSPC-LIBS technology were 0.098  μg·mL -1 , 0.18  μg·mL -1 , 0.83  μg·mL -1 , and 0.046  μg·mL -1 , respectively, which provided greater improvement than the direct bulk liquid analysis using LIBS.

  5. Deployable Fresnel Rings

    NASA Technical Reports Server (NTRS)

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.; Lin, Gregory Y.

    2014-01-01

    Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the

  6. Thermal vacuum real-life test of an Marconi Space and Defence Systems (MSDS) solar-array drive mechanism (MSDS 002). First four years of operation

    NASA Astrophysics Data System (ADS)

    Parker, K.; Douglas, A.; Burke, W. R.

    1981-01-01

    The first part of a 7 yr life test on a mechanism which turns a satellite solar array at 1rev/day is reported. A thermal transfer shroud, surrounding the mechanism in a vacuum chamber, is held at a constant temperature of 22.5 C while the shaft temperature, measured near the top of the shaft at the large bearing, is changed at 6-monthly intervals so that it operates alternately at 60 and 10 C. At the beginning of each 6-monthly cycle, 30 eclipse simulations are performed, i.e., the shaft temperature is reduced from 60 C to 0 C in 72 min and is returned to 60 C in as short a time as possible. Apart from a very small increase in motor power during eclipse simulation, no changes in the mechanism parameters occur with temperature. The mechanism operates within motor power and angular rotation accuracy specifications. The electrical noise on all slip rings increased during the first two years, but then slowly decreased. Certain slip ring pairs show a noise level in excess of the arbitrary limits set at the start of the test, and two slip ring pairs give large periodic noise transients which may be due to mechanical damage to the slip rings or brushes.

  7. Mechanical improvement of metal reinforcement rings for a finite ring-shaped superconducting bulk

    NASA Astrophysics Data System (ADS)

    Huang, Chen-Guang; Zhou, You-He

    2018-03-01

    As a key technique, reinforcement of type-II superconducting bulks with metal rings can efficiently improve their mechanical properties to enhance the maximum trapped field. In this paper, we study the magnetostrictive and fracture behaviors of a finite superconducting ring bulk reinforced by three typical reinforcing structures composed of metal rings during the magnetizing process by means of the minimization of magnetic energy and the finite element method. After a field-dependent critical current density is adopted, the magnetostriction, pinning-induced stress, and crack tip stress intensity factor are calculated considering the demagnetization effects. The results show that the mechanical properties of the ring bulk are strongly dependent on the reinforcing structure and the material and geometrical parameters of the metal rings. Introducing the metal ring can significantly reduce the hoop stress, and the reduction effect by internal reinforcement is much improved relative to external reinforcement. By comparison, bilateral reinforcement seems to be the best candidate structure. Only when the metal rings have particular Young's modulus and radial thickness will they contribute to improve the mechanical properties the most. In addition, if an edge crack is pre-existing in the ring bulk, the presence of metal rings can effectively avoid crack propagation since it reduces the crack tip stress intensity factor by nearly one order of magnitude.

  8. Ring rotational speed trend analysis by FEM approach in a Ring Rolling process

    NASA Astrophysics Data System (ADS)

    Allegri, G.; Giorleo, L.; Ceretti, E.

    2018-05-01

    Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. In this process two different deformations occur in order to reduce the width and the height of a preform hollow ring; as results a diameter expansion is obtained. In order to guarantee a uniform deformation, the preform is forced toward the Driver Roll whose aim is to transmit the rotation to the ring. The ring rotational speed selection is fundamental because the higher is the speed the higher will be the axial symmetry of the deformation process. However, it is important to underline that the rotational speed will affect not only the final ring geometry but also the loads and energy needed to produce it. Despite this importance in industrial environment, usually, a constant value for the Driver Roll angular velocity is set so to result in a decreasing trend law for the ring rotational speed. The main risk due to this approach is not fulfilling the axial symmetric constrain (due to the diameter expansion) and to generate a high localized ring section deformation. In order to improve the knowledge about this topic in the present paper three different ring rotational speed trends (constant, linearly increasing and linearly decreasing) were investigated by FEM approach. Results were compared in terms of geometrical and dimensional analysis, loads and energies required.

  9. Purifying Aluminum by Vacuum Distillation

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1985-01-01

    Proposed method for purifying aluminum employs one-step vacuum distillation. Raw material for process impure aluminum produced in electrolysis of aluminum ore. Impure metal melted in vacuum. Since aluminum has much higher vapor pressure than other constituents, boils off and condenses on nearby cold surfaces in proportions much greater than those of other constituents.

  10. Facility and Methods Developed for Simulated Space Vacuum Ultraviolet Exposure Testing of Polymer Films

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Pietromica, Anthony J.; Stueber, Thomas J.; Sechkar, Edward A.; Messer, Russell K.

    2002-01-01

    moveable cesium iodide VUV phototube, and two thermocouples for temperature measurement. The vacuum chamber and exterior equipment is shown. Each VUV lamp is located at the top of the chamber with its projection-tube pushed through an O-ring compression fitting. The lamp assemblies are located on ports that can be isolated from the rest of the vacuum chamber, permitting maintenance or replacement of the lamps without breaking vacuum in the main chamber where the samples are located. A view of two of the four interior VUV-exposure compartments, including the moveable sample stages and detector holders is also shown. Glenn is using this facility to support testing of Next Generation Space Telescope sunshield materials that is being led by the NASA Goddard Space Flight Center and to develop an understanding of the wavelength, intensity, and temperature dependence of VUV-induced polymer degradation.

  11. Ring correlations in random networks.

    PubMed

    Sadjadi, Mahdi; Thorpe, M F

    2016-12-01

    We examine the correlations between rings in random network glasses in two dimensions as a function of their separation. Initially, we use the topological separation (measured by the number of intervening rings), but this leads to pseudo-long-range correlations due to a lack of topological charge neutrality in the shells surrounding a central ring. This effect is associated with the noncircular nature of the shells. It is, therefore, necessary to use the geometrical distance between ring centers. Hence we find a generalization of the Aboav-Weaire law out to larger distances, with the correlations between rings decaying away when two rings are more than about three rings apart.

  12. Catabolism of the Last Two Steroid Rings in Mycobacterium tuberculosis and Other Bacteria

    PubMed Central

    Crowe, Adam M.; Casabon, Israël; Brown, Kirstin L.; Liu, Jie; Lian, Jennifer; Rogalski, Jason C.; Hurst, Timothy E.; Snieckus, Victor; Foster, Leonard J.

    2017-01-01

    ABSTRACT Most mycolic acid-containing actinobacteria and some proteobacteria use steroids as growth substrates, but the catabolism of the last two steroid rings has yet to be elucidated. In Mycobacterium tuberculosis, this pathway includes virulence determinants and has been proposed to be encoded by the KstR2-regulated genes, which include a predicted coenzyme A (CoA) transferase gene (ipdAB) and an acyl-CoA reductase gene (ipdC). In the presence of cholesterol, ΔipdC and ΔipdAB mutants of either M. tuberculosis or Rhodococcus jostii strain RHA1 accumulated previously undescribed metabolites: 3aα-H-4α(carboxyl-CoA)-5-hydroxy-7aβ-methylhexahydro-1-indanone (5-OH HIC-CoA) and (R)-2-(2-carboxyethyl)-3-methyl-6-oxocyclohex-1-ene-1-carboxyl-CoA (COCHEA-CoA), respectively. A ΔfadE32 mutant of Mycobacterium smegmatis accumulated 4-methyl-5-oxo-octanedioic acid (MOODA). Incubation of synthetic 5-OH HIC-CoA with purified IpdF, IpdC, and enoyl-CoA hydratase 20 (EchA20), a crotonase superfamily member, yielded COCHEA-CoA and, upon further incubation with IpdAB and a CoA thiolase, yielded MOODA-CoA. Based on these studies, we propose a pathway for the final steps of steroid catabolism in which the 5-member ring is hydrolyzed by EchA20, followed by hydrolysis of the 6-member ring by IpdAB. Metabolites accumulated by ΔipdF and ΔechA20 mutants support the model. The conservation of these genes in known steroid-degrading bacteria suggests that the pathway is shared. This pathway further predicts that cholesterol catabolism yields four propionyl-CoAs, four acetyl-CoAs, one pyruvate, and one succinyl-CoA. Finally, a ΔipdAB M. tuberculosis mutant did not survive in macrophages and displayed severely depleted CoASH levels that correlated with a cholesterol-dependent toxicity. Our results together with the developed tools provide a basis for further elucidating bacterial steroid catabolism and virulence determinants in M. tuberculosis. PMID:28377529

  13. Breakdown-Resistant RF Connectors for Vacuum

    NASA Technical Reports Server (NTRS)

    Caro, Edward R.; Bonazza, Walter J.

    1987-01-01

    Resilient inserts compensate for insulation shrinkage. Coaxial-cable connector for radio-frequency (RF) energy resists electrical breakdown in vacuum. Used on RF equipment in vacuum chambers as well as in spaceborne radar and communication gear.

  14. Seal ring installation tool

    NASA Technical Reports Server (NTRS)

    Haselmaier, L. Haynes (Inventor)

    2004-01-01

    A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

  15. Breather cloth for vacuum curing

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1979-01-01

    Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

  16. Vacuum Gas Tungsten Arc Welding

    NASA Technical Reports Server (NTRS)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  17. Neptune - full ring system

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This pair of Voyager 2 images (FDS 11446.21 and 11448.10), two 591-s exposures obtained through the clear filter of the wide angle camera, show the full ring system with the highest sensitivity. Visible in this figure are the bright, narrow N53 and N63 rings, the diffuse N42 ring, and (faintly) the plateau outside of the N53 ring (with its slight brightening near 57,500 km).

  18. Barely Bisected Rings

    NASA Image and Video Library

    2016-09-12

    Saturn's shadow stretched beyond the edge of its rings for many years after Cassini first arrived at Saturn, casting an ever-lengthening shadow that reached its maximum extent at the planet's 2009 equinox. This image captured the moment in 2015 when the shrinking shadow just barely reached across the entire main ring system. The shadow will continue to shrink until the planet's northern summer solstice, at which point it will once again start lengthening across the rings, reaching across them in 2019. Like Earth, Saturn is tilted on its axis. And, just as on Earth, as the sun climbs higher in the sky, shadows get shorter. The projection of the planet's shadow onto the rings shrinks and grows over the course of its 29-year-long orbit, as the angle of the sun changes with respect to Saturn's equator. This view looks toward the sunlit side of the rings from about 11 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Jan. 16, 2015. The view was obtained at a distance of approximately 1.6 million miles (2.5 million kilometers) from Saturn. Image scale is about 90 miles (150 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20498

  19. Particle sizes in Saturn's rings from UVIS stellar occultations 1. Variations with ring region

    NASA Astrophysics Data System (ADS)

    Colwell, J. E.; Esposito, L. W.; Cooney, J. H.

    2018-01-01

    The Cassini spacecraft's Ultraviolet Imaging Spectrograph (UVIS) includes a high speed photometer (HSP) that has observed stellar occultations by Saturn's rings with a radial resolution of ∼10 m. In the absence of intervening ring material, the time series of measurements by the HSP is described by Poisson statistics in which the variance equals the mean. The finite sizes of the ring particles occulting the star lead to a variance that is larger than the mean due to correlations in the blocking of photons due to finite particle size and due to random variations in the number of individual particles in each measurement area. This effect was first exploited by Showalter and Nicholson (1990) with the stellar occultation observed by Voyager 2. At a given optical depth, a larger excess variance corresponds to larger particles or clumps that results in greater variation of the signal from measurement to measurement. Here we present analysis of the excess variance in occultations observed by Cassini UVIS. We observe differences in the best-fitting particle size in different ring regions. The C ring plateaus show a distinctly smaller effective particle size, R, than the background C ring, while the background C ring itself shows a positive correlation between R and optical depth. The innermost 700 km of the B ring has a distribution of excess variance with optical depth that is consistent with the C ring ramp and C ring but not with the remainder of the B1 region. The Cassini Division, while similar to the C ring in spectral and structural properties, has different trends in effective particle size with optical depth. There are discrete jumps in R on either side of the Cassini Division ramp, while the C ring ramp shows a smooth transition in R from the C ring to the B ring. The A ring is dominated by self-gravity wakes whose shadow size depends on the occultation geometry. The spectral ;halo; regions around the strongest density waves in the A ring correspond to

  20. Apparatus For Metal/Inert-Gas Welding In Vacuum

    NASA Technical Reports Server (NTRS)

    Stocks, C. O.

    1994-01-01

    Metal/inert-gas welding-torch assembly operates in vacuum. Plasma generated in interior chamber and focused onto workpiece in vacuum. Pinch rollers feed wire to weld puddle. Controlled flow of plasma reduces dispersal in vacuum, preventing extinction.

  1. High-Affinity Accumulation of Chloroquine by Mouse Erythrocytes Infected with Plasmodium berghei

    PubMed Central

    Fitch, Coy D.; Yunis, Norman G.; Chevli, Rekha; Gonzalez, Yolanda

    1974-01-01

    Washed erythrocytes infected with chloroquine-susceptible (CS) or with chloroquine-resistant (CR) P. berghei were used in model systems in vitro to study the accumulation of chloroquine with high affinity. The CS model could achieve distribution ratios (chloroquine in cells: chloroquine in medium) of 100 in the absence of substrate. 200—300 in the presence of 10 mM pyruvate or lactate, and over 600 in the presence of 1 mM glucose or glycerol. In comparable studies of the CR model, the distribution ratios were 100 in the absence of substrate and 300 or less in the presence of glucose or glycerol. The presence of lactate stimulated chloroquine accumulation in the CR model, whereas the presence of pyruvate did not. Lactate production from glucose and glycerol was undiminished in the CR model, and ATP concentrations were higher than in the CS model. Cold, iodoacetate, 2,4-dinitrophenol, or decreasing pH inhibited chloroquine accumulation in both models. These findings demonstrate substrate involvement in the accumulation of chloroquine with high affinity. In studies of the CS model, certain compounds competitively inhibited chloroquine accumulation, while others did not. This finding is attributable to a specific receptor that imposes structural constraints on the process of accumulation. For chloroquine analogues, the position and length of the side chain, the terminal nitrogen atom of the side chain, and the nitrogen atom in the quinoline ring are important determinants of binding to this receptor. PMID:4600044

  2. TFTR diagnostic vacuum controller

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Olsen, D.; Persons, R.

    1981-01-01

    The TFTR diagnostic vacuum controller (DVC) provides in conjunction with the Central Instrumentation Control and Data Acquisition System (CICADA), control and monitoring for the pumps, valves and gauges associated with each individual diagnostic vacuum system. There will be approximately 50 systems on TFTR. Two standard versions of the controller (A and B) wil be provided in order to meet the requirements of two diagnostic manifold arrangements. All pump and valve sequencing, as well as protection features, will be implemented by the controller.

  3. Measurement and Modeling of Water-Vapor Diffusion in Elastomers with Impact in Humidity and Vacuum Measurements

    NASA Astrophysics Data System (ADS)

    Šetina, Janez; Sefa, Makfir; Erjavec, Bojan; Hudoklin, Domen

    2013-03-01

    The dynamics of water-vapor dissolution in Viton O-rings is measured with a gravimetric method using a precise mass comparator. A sample gasket was degassed in high vacuum for a sufficiently long period to remove more than 99 % of the dissolved water vapor. After that, it was exposed to the ambient atmosphere with a controlled temperature, and relative humidity and water-vapor uptake curves were measured gravimetrically with a precise balance. The dynamics of a water-vapor release into vacuum from another sample that was previously saturated with water vapor at room temperature was determined. The sample was placed in a vacuum outgassing rate measurement apparatus. The time dependence of the evolved water vapor was calculated by integrating the measured outgassing rate. The physical process of water absorption can be described by the diffusion equation. The geometry of the samples required solving the diffusion equation in cylindrical coordinates. This was done numerically using a finite-difference method. As a result of the modeling, room temperature values of the diffusion constant D, the solubility s, and the permeability K = D× s of water vapor in the sample material (Viton A-401C) were obtained. For sample 1, we obtained D = 8.0 × 10 ^{-8} cm2 {\\cdot } s^{-1} and s = 6.5 × 10^{-7} g {\\cdot } cm^-3 Pa^{-1}, while for sample 2, D = 3.0 × 10^{-7} cm2 s^{-1} and s = 3.5 × 10^{-7} g {\\cdot } cm^{-3} {\\cdot } Pa^{-1}.

  4. Vehicle-Level Oxygen/Methane Propulsion System Hotfire Testing at Thermal Vacuum Conditions

    NASA Technical Reports Server (NTRS)

    Morehead, Robert L.; Melcher, J. C.; Atwell, Matthew J.; Hurlbert, Eric A.; Desai, Pooja; Werlink, Rudy

    2017-01-01

    A prototype integrated liquid oxygen/liquid methane propulsion system was hot-fire tested at a variety of simulated altitude and thermal conditions in the NASA Glenn Research Center Plum Brook Station In-Space Propulsion Thermal Vacuum Chamber (formerly B2). This test campaign served two purposes: 1) Characterize the performance of the Plum Brook facility in vacuum accumulator mode and 2) Collect the unique data set of an integrated LOX/Methane propulsion system operating in high altitude and thermal vacuum environments (a first). Data from this propulsion system prototype could inform the design of future spacecraft in-space propulsion systems, including landers. The test vehicle for this campaign was the Integrated Cryogenic Propulsion Test Article (ICPTA), which was constructed for this project using assets from the former Morpheus Project rebuilt and outfitted with additional new hardware. The ICPTA utilizes one 2,800 lbf main engine, two 28 lbf and two 7 lbf reaction control engines mounted in two pods, four 48-inch propellant tanks (two each for liquid oxygen and liquid methane), and a cold helium system for propellant tank pressurization. Several hundred sensors on the ICPTA and many more in the test cell collected data to characterize the operation of the vehicle and facility. Multiple notable experiments were performed during this test campaign, many for the first time, including pressure-fed cryogenic reaction control system characterization over a wide range of conditions, coil-on-plug ignition system demonstration at the vehicle level, integrated main engine/RCS operation, and a non-intrusive propellant mass gauging system. The test data includes water-hammer and thermal heat leak data critical to validating models for use in future vehicle design activities. This successful test campaign demonstrated the performance of the updated Plum Brook In-Space Propulsion thermal vacuum chamber and incrementally advanced the state of LOX/Methane propulsion

  5. SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Degraff, Brian D.; Howell, Matthew P.; Kim, Sang-Ho

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinneymore » pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.« less

  6. The 1995 Saturn Ring-Plane Crossings: Ring Thickness and Small Inner Satellites

    NASA Astrophysics Data System (ADS)

    Poulet, F.; Sicardy, B.

    1996-09-01

    The May 22() th and August 10() th, 1995, Saturn ring-plane crossings by the Earth were observed from the 2-m and 1-m telescopes at Pic du Midi, the 2.2-m telescope of the University of Hawaii, and with the Adonis adaptive optics camera at the 3.6-m telescope of the European Southern Observatory (ESO). Observations were made with either a 0.9 mu m or 2.2 mu m (short K) methane band filter. The radial brightness profiles of the rings indicate that the outer F ring dominates the apparent edge-on thickness of the system, with a vertically integrated equivalent width of 0.8-1.0 km near a radius of 130,000 km. The photometric behaviors of the A, B, and C rings and of the Cassini Division have been analyzed using a classical radiative transfer code which includes illumination by the Sun and by the planet. The F ring is modelled as a physically thick ribbon (thickness h) composed of large particles embedded in dust. The observed profiles can be explained if the F ring is both optically thick (tau ~ 0.15-0.25), and physically thick (h at least ~ 1.5 km). The large particles dominate the F ring's photometric behavior in backscattered light. Constraints on the particle properties in the other rings have been derived. The dimming of the rings around August 10, 1995 provided ideal conditions to study the small inner satellites. Besides Janus, Epimetheus and Pandora, two unresolved objects were detected in the ESO frames. They have been identified with the objects 1995S5 and 1995S6, detected several hours later by the Hubble Space Telescope (Nicholson et al. 1996, Science 272, 509--515). Combining the ESO and HST data, we derive orbital and photometric parameters for these objects. In particular, we improve the orbital parameters of 1995S5, whose orbital radius is now close to that of the F ring.

  7. Saturn's dynamic D ring

    USGS Publications Warehouse

    Hedman, M.M.; Burns, J.A.; Showalter, M.R.; Porco, C.C.; Nicholson, P.D.; Bosh, A.S.; Tiscareno, M.S.; Brown, R.H.; Buratti, B.J.; Baines, K.H.; Clark, R.

    2007-01-01

    The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, <40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60??. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of ??? 30 ?? km extending between orbital radii of 73,200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of ??? 60 ?? km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. ?? 2006 Elsevier Inc. All rights reserved.

  8. Fate of electroweak vacuum during preheating

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori

    2016-10-28

    Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after inflation, the additional mass term oscillates, and it can destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum bymore » properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton and -curvature couplings, and discuss possible dynamics that might relax them.« less

  9. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying

  10. Simulation of the synergistic low Earth orbit effects of vacuum thermal cycling, vacuum UV radiation, and atomic oxygen

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Degroh, Kim K.; Stidham, Curtis R.; Stueber, Thomas J.; Dever, Therese M.; Rodriguez, Elvin; Terlep, Judith A.

    1992-01-01

    In order to assess the low Earth orbit (LEO) durability of candidate space materials, it is necessary to use ground laboratory facilities which provide LEO environmental effects. A facility combining vacuum thermal cycling and vacuum ultraviolet (VUV) radiation has been designed and constructed at NASA Lewis Research Center for this purpose. This facility can also be operated without the VUV lamps. An additional facility can be used to provide VUV exposure only. By utilizing these facilities, followed by atomic oxygen exposure in an RF plasma asher, the effects of the individual vacuum thermal cycling and VUV environments can be compared to the effect of the combined vacuum thermal cycling/VUV environment on the atomic oxygen durability of materials. The synergistic effects of simulated LEO environmental conditions on materials were evaluated by first exposing materials to vacuum thermal cycling, VUV, and vacuum thermal cycling/VUV environments followed by exposure to atomic oxygen in an RP plasma asher. Candidate space power materials such as atomic oxygen protected polyimides and solar concentrator mirrors were evaluated using these facilities. Characteristics of the Vacuum Thermal Cycling/VUV Exposure Facility which simulates the temperature sequences and solar ultraviolet radiation exposure that would be experienced by a spacecraft surface in LEO are discussed. Results of durability evaluations of some candidate space power materials to the simulated LEO environmental conditions will also be discussed. Such results have indicated that for some materials, atomic oxygen durability is affected by previous exposure to thermal cycling and/or VUV exposure.

  11. Eyeing the E Ring

    NASA Image and Video Library

    2009-12-24

    NASA Cassini spacecraft takes a look at Saturn diffuse E ring which is formed from icy material spewing out of the south pole of the moon Enceladus. The E ring is seen nearly edge-on from slightly above the northern side of Saturn ring plane.

  12. Nearly Seamless Vacuum-Insulated Boxes

    NASA Technical Reports Server (NTRS)

    Stepanian, Christopher J.; Ou, Danny; Hu, Xiangjun

    2010-01-01

    A design concept, and a fabrication process that would implement the design concept, have been proposed for nearly seamless vacuum-insulated boxes that could be the main structural components of a variety of controlled-temperature containers, including common household refrigerators and insulating containers for shipping foods. In a typical case, a vacuum-insulated box would be shaped like a rectangular parallelepiped conventional refrigerator box having five fully closed sides and a hinged door on the sixth side. Although it is possible to construct the five-closed-side portion of the box as an assembly of five unitary vacuum-insulated panels, it is not desirable to do so because the relatively high thermal conductances of the seams between the panels would contribute significant amounts of heat leakage, relative to the leakage through the panels themselves. In contrast, the proposal would make it possible to reduce heat leakage by constructing the five-closed-side portion of the box plus the stationary portion (if any) of the sixth side as a single, seamless unit; the only remaining seam would be the edge seal around the door. The basic cross-sectional configuration of each side of a vacuum-insulated box according to the proposal would be that of a conventional vacuum-insulated panel: a low-density, porous core material filling a partially evacuated space between face sheets. However, neither the face sheets nor the core would be conventional. The face sheets would be opposite sides of a vacuum bag. The core material would be a flexible polymer-modified silica aerogel of the type described in Silica/Polymer and Silica/Polymer/Fiber Composite Aero - gels (MSC-23736) in this issue of NASA Tech Briefs. As noted in that article, the stiffness of this core material against compression is greater than that of prior aerogels. This is an important advantage because it translates to greater retention of thickness and, hence, of insulation performance when pressure is

  13. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  14. Compact vacuum insulation

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  15. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1993-01-01

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  16. Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes.

    PubMed

    Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

    2017-12-01

    Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  17. Hot piston ring tests

    NASA Technical Reports Server (NTRS)

    Allen, David J.; Tomazic, William A.

    1987-01-01

    As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

  18. Tree Rings: Timekeepers of the Past.

    ERIC Educational Resources Information Center

    Phipps, R. L.; McGowan, J.

    One of a series of general interest publications on science issues, this booklet describes the uses of tree rings in historical and biological recordkeeping. Separate sections cover the following topics: dating of tree rings, dating with tree rings, tree ring formation, tree ring identification, sample collections, tree ring cross dating, tree…

  19. Cavity-locked ring down spectroscopy

    DOEpatents

    Zare, Richard N.; Paldus, Barbara A.; Harb, Charles C.; Spence, Thomas

    2000-01-01

    Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

  20. Accidental ingestion of BiTine ring and a note on inefficient ring separation forceps.

    PubMed

    Baghele, Om Nemichand; Baghele, Mangala Om

    2011-01-01

    Accidental ingestion of medium-to-large instruments is relatively uncommon during dental treatment but can be potentially dangerous. A case of BiTine ring ingestion is presented with a note on inefficient ring separation forceps. A 28-year-old male patient accidentally ingested the BiTine ring (2 cm diameter, 0.5 cm outward projections) while it was being applied to a distoproximal cavity in tooth # 19. The ring placement forceps were excessively flexible; bending of the beaks towards the ring combined with a poor no-slippage mechanism led to sudden disengagement of the ring and accelerated movement towards the pharynx. We followed the patient with bulk forming agents and radiographs. Fortunately the ring passed out without any complications. Checking equipment and methods is as important as taking precautions against any preventable medical emergency. It is the responsibility of the clinician to check, verify and then use any instrument/equipment.

  1. Study on convection improvement of standard vacuum tube

    NASA Astrophysics Data System (ADS)

    He, J. H.; Du, W. P.; Qi, R. R.; He, J. X.

    2017-11-01

    For the standard all-glass vacuum tube collector, enhancing the vacuum tube axial natural convection can improve its thermal efficiency. According to the study of the standard all-glass vacuum tube, three kinds of guide plates which can inhibit the radial convection and increase axial natural convection are designed, and theory model is established. Experiments were carried out on vacuum tubes with three types of baffles and standard vacuum tubes without the improvement. The results show that T-type guide plate is better than that of Y-type guide plate on restraining convection and increasing axial radial convection effect, Y type is better than that of flat plate type, all guide plates are better than no change; the thermal efficiency of the tube was 2.6% higher than that of the unmodified standard vacuum tube. The efficiency of the system in the experiment can be increased by 3.1%.

  2. 21 CFR 864.9125 - Vacuum-assisted blood collection system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

  3. 21 CFR 864.9125 - Vacuum-assisted blood collection system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

  4. 21 CFR 864.9125 - Vacuum-assisted blood collection system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

  5. 21 CFR 864.9125 - Vacuum-assisted blood collection system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

  6. 21 CFR 864.9125 - Vacuum-assisted blood collection system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vacuum-assisted blood collection system. 864.9125... Blood and Blood Products § 864.9125 Vacuum-assisted blood collection system. (a) Identification. A vacuum-assisted blood collection system is a device intended for medical purposes that uses a vacuum to...

  7. Solid sulfur in vacuum: Sublimation effects on surface microtexture, color and spectral reflectance, and applications to planetary surfaces

    NASA Technical Reports Server (NTRS)

    Nash, D. B.

    1987-01-01

    A form of sulfur that is white at room temperature and very fluffy in texture has been found in laboratory experiments on the effects of vacuum sublimation (evaporation) on solid sulfur. This work is an outgrowth of proton sputtering experiments on sulfur directed toward understanding Jovian magnetospheric effects on the surface of Io. Fluffy white sulfur is formed on the surface of solid yellow, tan, or brown sulfur melt freezes in vacuum by differential (fractional) evaporation of two or more sulfur molecular species present in the original sulfur; S(8) ring sulfur is thought to be the dominant sublimination phase lost to the vacuum sink, and polymeric chain sulfur S(u) the dominant residual phase that remains in place, forming the residual fluffy surface layer. The reflectance spectrum of the original sulfur surface is greaty modified by formation of the fluffy layer: the blue absorption band-edge and shoulder move 0.05 to 0.06 microns toward shorter wavelengths resulting in a permanent increase in reflectivity near 0.42 to 0.46 microns; the UV reflectivity below 0.40 microns is reduced. This form of sulfur should exist in large quantity on the surface of Io, especially in hotspot regions if there is solid free sulfur there that has solidified from a melt. Its color and spectra will indicate relative crystallization age on a scale of days to months and/or surface temperature distribution history.

  8. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 25.1433 Section 25.1433 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There...

  9. Plates for vacuum thermal fusion

    DOEpatents

    Davidson, James C.; Balch, Joseph W.

    2002-01-01

    A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

  10. Apparatus and method for creating a photonic densely-accumulated ray-point

    NASA Technical Reports Server (NTRS)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

  11. Photometry of Polar-Ring Galaxies

    NASA Astrophysics Data System (ADS)

    Godínez-Martínez, A.; Watson, A. M.; Matthews, L. D.; Sparke, L. S.

    2007-10-01

    We have obtained photometry in B and R for seven confirmed or probable polar-ring galaxies from the Polar-Ring Catalog of Whitmore et al. (1990). The rings show a range of colors from B - R ≈ 0.6 to B - R ≈ 1.7. The bluest rings have bright H II regions, which are direct evidence for recent star formation. The minimum age of the reddest ring, that in PRC B-20, is somewhat uncertain because of a lack of knowledge of the internal reddening and metallicity, but appears to be at least 1.2 Gyr. As such, this ring is likely to be stable for at least several rotation periods. This ring is an excellent candidate for future studies that might better determine if it is truly old.

  12. Researches on Position Detection for Vacuum Switch Electrode

    NASA Astrophysics Data System (ADS)

    Dong, Huajun; Guo, Yingjie; Li, Jie; Kong, Yihan

    2018-03-01

    Form and transformation character of vacuum arc is important influencing factor on the vacuum switch performance, and the dynamic separations of electrode is the chief effecting factor on the transformation of vacuum arcs forms. Consequently, how to detect the position of electrode to calculate the separations in the arcs image is of great significance. However, gray level distribution of vacuum arcs image isn’t even, the gray level of burning arcs is high, but the gray level of electrode is low, meanwhile, the forms of vacuum arcs changes sharply, the problems above restrict electrode position detection precisely. In this paper, algorithm of detecting electrode position base on vacuum arcs image was proposed. The digital image processing technology was used in vacuum switch arcs image analysis, the upper edge and lower edge were detected respectively, then linear fitting was done using the result of edge detection, the fitting result was the position of electrode, thus, accurate position detection of electrode was realized. From the experimental results, we can see that: algorithm described in this paper detected upper and lower edge of arcs successfully and the position of electrode was obtained through calculation.

  13. Ceramic vacuum tubes for geothermal well logging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kelly, R.D.

    1977-01-01

    Useful design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes are discussed for application to the development of high temperature well logs. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data are presented in the appendix.

  14. Improving the Accuracy of Laplacian Estimation with Novel Variable Inter-Ring Distances Concentric Ring Electrodes

    PubMed Central

    Makeyev, Oleksandr; Besio, Walter G.

    2016-01-01

    Noninvasive concentric ring electrodes are a promising alternative to conventional disc electrodes. Currently, the superiority of tripolar concentric ring electrodes over disc electrodes, in particular, in accuracy of Laplacian estimation, has been demonstrated in a range of applications. In our recent work, we have shown that accuracy of Laplacian estimation can be improved with multipolar concentric ring electrodes using a general approach to estimation of the Laplacian for an (n + 1)-polar electrode with n rings using the (4n + 1)-point method for n ≥ 2. This paper takes the next step toward further improving the Laplacian estimate by proposing novel variable inter-ring distances concentric ring electrodes. Derived using a modified (4n + 1)-point method, linearly increasing and decreasing inter-ring distances tripolar (n = 2) and quadripolar (n = 3) electrode configurations are compared to their constant inter-ring distances counterparts. Finite element method modeling and analytic results are consistent and suggest that increasing inter-ring distances electrode configurations may decrease the truncation error resulting in more accurate Laplacian estimates compared to respective constant inter-ring distances configurations. For currently used tripolar electrode configuration, the truncation error may be decreased more than two-fold, while for the quadripolar configuration more than a six-fold decrease is expected. PMID:27294933

  15. Improving the Accuracy of Laplacian Estimation with Novel Variable Inter-Ring Distances Concentric Ring Electrodes.

    PubMed

    Makeyev, Oleksandr; Besio, Walter G

    2016-06-10

    Noninvasive concentric ring electrodes are a promising alternative to conventional disc electrodes. Currently, the superiority of tripolar concentric ring electrodes over disc electrodes, in particular, in accuracy of Laplacian estimation, has been demonstrated in a range of applications. In our recent work, we have shown that accuracy of Laplacian estimation can be improved with multipolar concentric ring electrodes using a general approach to estimation of the Laplacian for an (n + 1)-polar electrode with n rings using the (4n + 1)-point method for n ≥ 2. This paper takes the next step toward further improving the Laplacian estimate by proposing novel variable inter-ring distances concentric ring electrodes. Derived using a modified (4n + 1)-point method, linearly increasing and decreasing inter-ring distances tripolar (n = 2) and quadripolar (n = 3) electrode configurations are compared to their constant inter-ring distances counterparts. Finite element method modeling and analytic results are consistent and suggest that increasing inter-ring distances electrode configurations may decrease the truncation error resulting in more accurate Laplacian estimates compared to respective constant inter-ring distances configurations. For currently used tripolar electrode configuration, the truncation error may be decreased more than two-fold, while for the quadripolar configuration more than a six-fold decrease is expected.

  16. Embryonic ring closure: Actomyosin rings do the two-step

    PubMed Central

    2016-01-01

    Actomyosin rings drive numerous closure processes, but the mechanisms by which they contract are still poorly understood. In this issue, Xue and Sokac (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201608025) show that actomyosin ring closure during Drosophila melanogaster cellularization uses two steps, only one of which involves Myosin-2. PMID:27799371

  17. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

  18. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

  19. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

  20. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

  1. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

  2. Scintillating C Ring

    NASA Image and Video Library

    2007-01-16

    Both luminous and translucent, the C ring sweeps out of the darkness of Saturn's shadow and obscures the planet at lower left. The ring is characterized by broad, isolated bright areas, or "plateaus," surrounded by fainter material. This view looks toward the unlit side of the rings from about 19 degrees above the ringplane. North on Saturn is up. The dark, inner B ring is seen at lower right. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 15, 2006 at a distance of approximately 632,000 kilometers (393,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 56 degrees. Image scale is 34 kilometers (21 miles) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA08855

  3. Radar imaging of Saturn's rings

    NASA Astrophysics Data System (ADS)

    Nicholson, Philip D.; French, Richard G.; Campbell, Donald B.; Margot, Jean-Luc; Nolan, Michael C.; Black, Gregory J.; Salo, Heikki J.

    2005-09-01

    We present delay-Doppler images of Saturn's rings based on radar observations made at Arecibo Observatory between 1999 and 2003, at a wavelength of 12.6 cm and at ring opening angles of 20.1°⩽|B|⩽26.7°. The average radar cross-section of the A ring is ˜77% relative to that of the B ring, while a stringent upper limit of 3% is placed on the cross-section of the C ring and 9% on that of the Cassini Division. These results are consistent with those obtained by Ostro et al. [1982, Icarus 49, 367-381] from radar observations at |B|=21.4°, but provide higher resolution maps of the rings' reflectivity profile. The average cross-section of the A and B rings, normalized by their projected unblocked area, is found to have decreased from 1.25±0.31 to 0.74±0.19 as the rings have opened up, while the circular polarization ratio has increased from 0.64±0.06 to 0.77±0.06. The steep decrease in cross-section is at variance with previous radar measurements [Ostro et al., 1980, Icarus 41, 381-388], and neither this nor the polarization variations are easily understood within the framework of either classical, many-particle-thick or monolayer ring models. One possible explanation involves vertical size segregation in the rings, whereby observations at larger elevation angles which see deeper into the rings preferentially see the larger particles concentrated near the rings' mid-plane. These larger particles may be less reflective and/or rougher and thus more depolarizing than the smaller ones. Images from all four years show a strong m=2 azimuthal asymmetry in the reflectivity of the A ring, with an amplitude of ±20% and minima at longitudes of 67±4° and 247±4° from the sub-Earth point. We attribute the asymmetry to the presence of gravitational wakes in the A ring as invoked by Colombo et al. [1976, Nature 264, 344-345] to explain the similar asymmetry long seen at optical wavelengths. A simple radiative transfer model suggests that the enhancement of the azimuthal

  4. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

  5. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

  6. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

  7. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

  8. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913....913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk... Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. ...

  9. Vacuum coupling of rotating superconducting rotor

    DOEpatents

    Shoykhet, Boris A.; Zhang, Burt Xudong; Driscoll, David Infante

    2003-12-02

    A rotating coupling allows a vacuum chamber in the rotor of a superconducting electric motor to be continually pumped out. The coupling consists of at least two concentric portions, one of which is allowed to rotate and the other of which is stationary. The coupling is located on the non-drive end of the rotor and is connected to a coolant supply and a vacuum pump. The coupling is smaller in diameter than the shaft of the rotor so that the shaft can be increased in diameter without having to increase the size of the vacuum seal.

  10. Uranus Rings in False Color

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This false-color view of the rings of Uranus was made from images taken by Voyager 2 on Jan. 21, 1986, from a distance of 4.17 million kilometers (2.59 million miles). All nine known rings are visible here; the somewhat fainter, pastel lines seen between them are contributed by the computer enhancement. Six 15-second narrow-angle images were used to extract color information from the extremely dark and faint rings. Two images each in the green, clear and violet filters were added together and averaged to find the proper color differences between the rings. The final image was made from these three color averages and represents an enhanced, false-color view. The image shows that the brightest, or epsilon, ring at top is neutral in color, with the fainter eight other rings showing color differences between them. Moving down, toward Uranus, we see the delta, gamma and eta rings in shades of blue and green; the beta and alpha rings in somewhat lighter tones; and then a final set of three, known simply as the 4, 5 and 6 rings, in faint off-white tones. Scientists will use this color information to try to understand the nature and origin of the ring material. The resolution of this image is approximately 40 km (25 mi). The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  11. Engineering cell wall synthesis mechanism for enhanced PHB accumulation in E. coli.

    PubMed

    Zhang, Xing-Chen; Guo, Yingying; Liu, Xu; Chen, Xin-Guang; Wu, Qiong; Chen, Guo-Qiang

    2018-01-01

    The rigidity of bacterial cell walls synthesized by a complicated pathway limit the cell shapes as coccus, bar or ellipse or even fibers. A less rigid bacterium could be beneficial for intracellular accumulation of poly-3-hydroxybutyrate (PHB) as granular inclusion bodies. To understand how cell rigidity affects PHB accumulation, E. coli cell wall synthesis pathway was reinforced and weakened, respectively. Cell rigidity was achieved by thickening the cell walls via insertion of a constitutive gltA (encoding citrate synthase) promoter in front of a series of cell wall synthesis genes on the chromosome of several E. coli derivatives, resulting in 1.32-1.60 folds increase of Young's modulus in mechanical strength for longer E. coli cells over-expressing fission ring FtsZ protein inhibiting gene sulA. Cell rigidity was weakened by down regulating expressions of ten genes in the cell wall synthesis pathway using CRISPRi, leading to elastic cells with more spaces for PHB accumulation. The regulation on cell wall synthesis changes the cell rigidity: E. coli with thickened cell walls accumulated only 25% PHB while cell wall weakened E. coli produced 93% PHB. Manipulation on cell wall synthesis mechanism adds another possibility to morphology engineering of microorganisms. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  12. From coffee ring to spherulites ring of poly(ethylene oxide) film from drying droplet

    NASA Astrophysics Data System (ADS)

    Hu, Yinchun; Zhang, Xuerong; Qiu, Maibo; Wei, Yan; Zhou, Qiong; Huang, Di

    2018-03-01

    We discuss how the "spherulites ring" morphology and "coffee ring" profile of PEO film formed by the drying droplet at glass substrate with different heating rate. Upon increasing the heating rate of substrate, it is found that deposited PEO film from drying droplet shows the unusually observed "coffee ring" profile and "spherulites ring" morphology. The main mechanism for this phenomenon is proposed to be an enhanced Marangoni convection which is induced by the increased solute concentration gradient and reduced viscous force above 70 °C. A simple formation mechanism of the unusually observed "coffee ring" profile and "spherulites ring" morphology is proposed. These findings can be exploited to trace the center of Marangoni convection, with potential applications in designing the spherulite patterns of crystalline polymer films in ink-jet printing and self-assembly fields.

  13. Evaporation-induced self-assembly of quantum dots-based concentric rings on polymer-based nanocomposite films.

    PubMed

    Zhang, Shaofu; Luan, Weiling; Zhong, Qixin; Yin, Shaofeng; Yang, Fuqian

    2016-10-12

    The "ball-on-film" template is used to construct concentric rings on the surface of PMMA-QDs (polymethyl methacrylate - quantum dots) nanocomposite films via the evaporation of pure chloroform droplets, which are confined by a steel ball. The concentric rings consist of QDs, as revealed by the fluorescence images of the concentric rings. The photoluminescence intensity of the concentric rings increases with the increase of the distance to the ball center, suggesting that the amount of QDs accumulated around the contact line at individual stick state increases with the increase of the distance to the ball center. Both the wavelength and cross-sectional area (width) of the concentric rings increase approximately linearly with increasing distance to the ball center, independent of the ball size, the film thickness and the QDs concentration. For the PMMA-QDs nanocomposite films prepared from the same QDs concentration in chloroform, the thicker the PMMA-QDs nanocomposite film, the larger the wavelength for the same distance to the ball center. The effect of confinement of two steel balls on the surface patterns over the PMMA-QDs nanocomposite films is studied via a template of "two spheres on film". Symmetric surface patterns are formed. There exist two types of featureless zone between the two balls, depending on the distance between the two balls: one is the inner featureless zone and the other is the outer featureless zone. The size of both featureless zones increases with the increase of the ball distance.

  14. Systematic Search for Rings around Kepler Planet Candidates: Constraints on Ring Size and Occurrence Rate

    NASA Astrophysics Data System (ADS)

    Aizawa, Masataka; Masuda, Kento; Kawahara, Hajime; Suto, Yasushi

    2018-05-01

    We perform a systematic search for rings around 168 Kepler planet candidates with sufficient signal-to-noise ratios that are selected from all of the short-cadence data. We fit ringed and ringless models to their light curves and compare the fitting results to search for the signatures of planetary rings. First, we identify 29 tentative systems, for which the ringed models exhibit statistically significant improvement over the ringless models. The light curves of those systems are individually examined, but we are not able to identify any candidate that indicates evidence for rings. In turn, we find several mechanisms of false positives that would produce ringlike signals, and the null detection enables us to place upper limits on the size of the rings. Furthermore, assuming the tidal alignment between axes of the planetary rings and orbits, we conclude that the occurrence rate of rings larger than twice the planetary radius is less than 15%. Even though the majority of our targets are short-period planets, our null detection provides statistical and quantitative constraints on largely uncertain theoretical models of the origin, formation, and evolution of planetary rings.

  15. Rings Through Atmosphere

    NASA Image and Video Library

    2010-05-26

    NASA Cassini spacecraft looks toward the limb of Saturn and, on the right of this image, views part of the rings through the planet atmosphere. Saturn atmosphere can distort the view of the rings from some angles.

  16. Vacuum-jacketed transfer line installation technique

    NASA Technical Reports Server (NTRS)

    Bowers, W. M.

    1968-01-01

    Rolling-type spacers in the form of steel balls retained in appropriate sleeves affixed at intervals to the exterior of the transfer line facilitate the installation of a vacuum-jacketed line. They act as standoffs to position the transfer line concentrically within the vacuum jacket line.

  17. Effect of electrical current on the tribological behavior of the Cu-WS2-G composites in air and vacuum

    NASA Astrophysics Data System (ADS)

    Qian, Gang; Feng, Yi; Li, Bin; Huang, Shiyin; Liu, Hongjuan; Ding, Kewang

    2013-03-01

    As the traditional graphite-based composites cannot meet the requirement of rapid developing modern industry, novel sliding electrical contact materials with high self-lubricating performance in multiple environments are eagerly required. Herein a copper-based composite with WS2 and graphite as solid lubricant are fabricated by powder metallurgy hot-pressed method. The friction and wear behaviors of the composites with and without current are investigated under the condition with sliding velocity of 10 m/s and normal load of 2.5 N/cm2 in both air and vacuum. Morphologies of the worn surfaces are observed by optical microscope and compositions of the lubricating films are analyzed by XPS. Surface profile curves and roughness of the worn surfaces are obtained by 2205 surface profiler. The results of wear tests show that the friction coefficient and wear volume loss of the composites with current are greater than that without current in both air and vacuum due to the adverse effects of electrical current which damaged the lubricating film partially and roughed the worn surfaces. XPS results demonstrate that the lubricating film formed in air is composed of oxides of Cu, WS2, elemental S and graphite, while the lubricating film formed in vacuum is composed of Cu, WS2 and graphite. Because of the synergetic lubricating action of oxides of Cu, WS2 and graphite, the composites show low friction coefficient and wear volume loss in air condition. Owing to the fact that graphite loses its lubricity which makes WS2 become the only lubricant, severe adhesive and abrasive wear occur and result in a high value of wear rate in vacuum condition. The formation of the lubricating film on the contact interface between the brush and ring is one of the factors which can greatly affect the wear performance of the brushes. The low contact voltage drop of the composites in vacuum condition is attributed to the high content of Cu in the surface film. This study fabricated a kind of new

  18. Thermodynamic performance of multi-stage gradational lead screw vacuum pump

    NASA Astrophysics Data System (ADS)

    Zhao, Fan; Zhang, Shiwei; Sun, Kun; Zhang, Zhijun

    2018-02-01

    As a kind of dry mechanical vacuum pump, the twin-screw vacuum pump has an outstanding pumping performance during operation, widely used in the semiconductor industry. Compared with the constant lead screw (CLS) vacuum pump, the gradational lead screw (GLS) vacuum pump is more popularly applied in recent years. Nevertheless, not many comparative studies on the thermodynamic performance of GLS vacuum pump can be found in the literature. Our study focuses on one type of GLS vacuum pump, the multi-stage gradational lead screw (MGLS) vacuum pump, gives a detailed description of its construction and illustrates it with the drawing. Based on the structural analysis, the thermodynamic procedure is divided into four distinctive processes, including sucking process, transferring (compressing) process, backlashing process and exhausting process. The internal mechanism of each process is qualitatively illustrated and the mathematical expressions of seven thermodynamic parameters are given under the ideal situation. The performance curves of MGLS vacuum pump are plotted by MATLAB software and compared with those of the CLS vacuum pump in the same case. The results can well explain why the MGLS vacuum pump has more favorable pumping performance than the CLS vacuum pump in saving energy, reducing noise and heat dissipation.

  19. Vacuum tool manipulator

    DOEpatents

    Zollinger, William T.

    1993-01-01

    Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm.

  20. Ring-through-ring molecular shuttling in a saturated [3]rotaxane

    NASA Astrophysics Data System (ADS)

    Zhu, Kelong; Baggi, Giorgio; Loeb, Stephen J.

    2018-06-01

    Mechanically interlocked molecules such as rotaxanes and catenanes comprise two or more components whose motion relative to each other can be controlled. A [2]rotaxane molecular shuttle, for example, consists of an axle bearing two recognition sites and a single macrocyclic wheel that can undergo a to-and-fro motion along the axle—shuttling between the recognition sites. The ability of mechanically interlocked molecules to undergo this type of large-amplitude change is the core mechanism behind almost every interlocked molecular switch or machine, including sophisticated mechanical systems such as a molecular elevator and a peptide synthesizer. Here, as a way to expand the scope of dynamics possible at the molecular level, we have developed a molecular shuttling mechanism involving the exchange of rings between two recognition sites in a saturated [3]rotaxane (one with no empty recognition sites). This was accomplished by passing a smaller ring through a larger one, thus achieving ring-through-ring molecular shuttling.

  1. REVIEWS OF TOPICAL PROBLEMS: Cosmic vacuum

    NASA Astrophysics Data System (ADS)

    Chernin, Artur D.

    2001-11-01

    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered.

  2. Source replenishment device for vacuum deposition

    DOEpatents

    Hill, Ronald A.

    1988-01-01

    A material source replenishment device for use with a vacuum deposition apparatus. The source replenishment device comprises an intermittent motion producing gear arrangement disposed within the vacuum deposition chamber. An elongated rod having one end operably connected to the gearing arrangement is provided with a multiarmed head at the opposite end disposed adjacent the heating element of the vacuum deposition apparatus. An inverted U-shaped source material element is releasably attached to the outer end of each arm member whereby said multiarmed head is moved to locate a first of said material elements above said heating element, whereupon said multiarmed head is lowered to engage said material element with the heating element and further lowered to release said material element on the heating element. After vaporization of said material element, second and subsequent material elements may be provided to the heating element without the need for opening the vacuum deposition apparatus to the atmosphere.

  3. Source replenishment device for vacuum deposition

    DOEpatents

    Hill, R.A.

    1986-05-15

    A material source replenishment device for use with a vacuum deposition apparatus is described. The source replenishment device comprises an intermittent motion producing gear arrangement disposed within the vacuum deposition chamber. An elongated rod having one end operably connected to the gearing arrangement is provided with a multiarmed head at the opposite end disposed adjacent the heating element of the vacuum deposition apparatus. An inverted U-shaped source material element is releasably attached to the outer end of each arm member whereby said multiarmed head is moved to locate a first of said material elements above said heating element, whereupon said multiarmed head is lowered to engage said material element with the heating element and further lowered to release said material element on the heating element. After vaporization of said material element, second and subsequent material elements may be provided to the heating element without the need for opening the vacuum deposition apparatus to the atmosphere.

  4. Waveguide quantum electrodynamics in squeezed vacuum

    NASA Astrophysics Data System (ADS)

    You, Jieyu; Liao, Zeyang; Li, Sheng-Wen; Zubairy, M. Suhail

    2018-02-01

    We study the dynamics of a general multiemitter system coupled to the squeezed vacuum reservoir and derive a master equation for this system based on the Weisskopf-Wigner approximation. In this theory, we include the effect of positions of the squeezing sources which is usually neglected in the previous studies. We apply this theory to a quasi-one-dimensional waveguide case where the squeezing in one dimension is experimentally achievable. We show that while dipole-dipole interaction induced by ordinary vacuum depends on the emitter separation, the two-photon process due to the squeezed vacuum depends on the positions of the emitters with respect to the squeezing sources. The dephasing rate, decay rate, and the resonance fluorescence of the waveguide-QED in the squeezed vacuum are controllable by changing the positions of emitters. Furthermore, we demonstrate that the stationary maximum entangled NOON state for identical emitters can be reached with arbitrary initial state when the center-of-mass position of the emitters satisfies certain conditions.

  5. Transcription coactivator Arabidopsis ANGUSTIFOLIA3 modulates anthocyanin accumulation and light-induced root elongation through transrepression of Constitutive Photomorphogenic1.

    PubMed

    Meng, Lai-Sheng

    2015-04-01

    ANGUSTIFOLIA3 (AN3), a transcription coactivator, is implicated in modulating cell proliferation. In this study, I found that AN3 is a novel regulator of anthocyanin biosynthesis and light-induced root elongation. Seedlings and seeds lacking AN3 activity presented significantly reduced anthocyanin accumulation and light-induced root elongation, whereas those of transgenic plants harbouring the 35S:AN3 construct exhibited increased anthocyanin accumulation. AN3 is required for the proper expression of other genes that affect anthocyanin accumulation and light-induced root elongation, Constitutive Photomorphogenic1 (COP1), encoding a RING motif - containing E3 ubiquitin ligase. AN3 was associated with COP1 promoter in vivo. Thus, AN3 may act with other proteins that bind to COP1 promoter to promote anthocyanin accumulation and inhibit light-induced root elongation. © 2014 John Wiley & Sons Ltd.

  6. Study of Storage Ring Free-Electron Laser Using Experimental and Simulation Approaches

    NASA Astrophysics Data System (ADS)

    Jia, Botao

    2011-12-01

    The Duke electron storage ring, first commissioned in November of 1994, has been developed as a dedicated driver for storage ring free-electron lasers (SRFELs) operating in a wide wavelength range from infrared, to visible, to ultraviolet (UV) and vacuum ultraviolet (VUV). The storage ring has a long straight section for various insertion devices and can be operated in a wide energy range (0.25 GeV to 1.15 GeV). Commissioned in 1995, the first free-electron laser (FEL) on the Duke storage ring was the OK-4 FEL, an optical klystron with two planar undulators sandwiching a buncher magnet. In 2005, the OK-5 FEL with two helical undulators was commissioned. Operating four undulators---two OK-4 and two OK-5 undulators, the world's first distributed optical klystron FEL was brought to operation in 2005. Via Compton scattering of FEL photons and electrons in the storage ring, the Duke FEL drives the world's most powerful, nearly monochromatic, and polarized Compton gamma-ray source, the High Intensity Gamma-ray Source (HIgammaS). Today, a variety of configurations of the storage ring FELs at Duke have been used in a wide range of research areas from nuclear physics to biophysics, from chemical and medical research to industrial applications. The capability of accurately measuring the storage ring electron beam energy spread is crucial for understanding the longitudinal beam dynamics and the dynamics of the storage ring FEL. In this dissertation, we have successfully developed a noninvasive, versatile, and accurate method to measure the energy spread using optical klystron radiation. Novel numerical methods based upon the Gauss-Hermite expansion have been developed to treat both spectral broadening and modulation on an equal footing. Through properly configuring the optical klystron, this energy spread measurement method has a large dynamic range. In addition, a model-based scheme has been developed for correcting the electron beam emittance related inhomogeneous spectral

  7. A six-membered-ring incorporated Si-rhodamine for imaging of copper(ii) in lysosomes.

    PubMed

    Wang, Baogang; Cui, Xiaoyan; Zhang, Zhiqiang; Chai, Xiaoyun; Ding, Hao; Wu, Qiuye; Guo, Zhongwu; Wang, Ting

    2016-07-12

    The regulation of copper homeostasis in lysosomes of living cells is closely related to various physiological and pathological processes. Thus, it is of urgent need to develop a fluorescent probe for selectively and sensitively monitoring the location and concentration of lysosomal Cu(2+). Herein, a six-membered ring, thiosemicarbazide, was incorporated into a Si-rhodamine (SiR) scaffold for the first time, affording a SiR-based fluorescent probe SiRB-Cu. Through the effective Cu(2+)-triggered ring-opening process, the probe exhibits fast NIR chromogenic and fluorogenic responses to Cu(2+) within 2 min as the result of formation of a highly fluorescent product SiR-NCS. Compared with a five-membered ring, the expanded ring retains great tolerance to H(+), ensuring the superior sensitivity with a detection limit as low as 7.7 nM and 200-fold enhancement of relative fluorescence in the presence of 1.0 equiv. of Cu(2+) in pH = 5.0 solution, the physiological pH of lysosome. Moreover, the thiosemicarbazide moiety acts not only as the chelating and reactive site, but also as an efficient lysosome-targeting group, leading to the proactive accumulation of the probe into lysosomes. Taking advantage of these distinct properties, SiRB-Cu provides a functional probe suitable for imaging exogenous and endogenous lysosomal Cu(2+) with high imaging contrast and fidelity.

  8. Constraints on Particle Sizes in Saturn's G Ring from Ring Plane Crossing Observations

    NASA Astrophysics Data System (ADS)

    Throop, H. B.; Esposito, L. W.

    1996-09-01

    The ring plane crossings in 1995--96 allowed earth-based observations of Saturn's diffuse rings (Nicholson et al., Nature 272, 1996; De Pater et al. Icarus 121, 1996) at a phase angle of alpha ~ 5 deg . We calculate the G ring reflectance for steady state distributions of dust to km-sized bodies from a range of physical models which track the evolution of the G ring from its initial formation following the disruption of a progenitor satellite (Canup & Esposito 1996, \\ Icarus,\\ in press). We model scattering from the ring's small particles using an exact T-matrix method for nonspherical, absorptive particles (Mishchenko et al. 1996, \\ JGR Atmo., in press), large particles using the phase function and spectrum of Europa, and intermediate particles using a linear combination of the small and large limits. Two distinct particle size distributions from the CE96 model fit the observed spectrum. The first is that of a dusty ring, with the majority of ring reflectance in dust particles of relatedly shallow power law size distribution exponent q ~ 2.5. The second has equal reflectances from a) dust in the range q ~ 3.5 -- 6.5 and b) macroscopic bodies > 1 mm. In this second case, the respective slightly blue and red components combine to form the observed relatively flat spectrum. Although light scattering in backscatter is not sufficient to completely constrain the G ring size distribution, the distributions predicted by the CE96 model can explain the earth-based observations.

  9. Sugar maple sap volume increases as vacuum level is increased

    Treesearch

    Russell S. Walters; H. Clay Smith

    1975-01-01

    Maple sap yields collected by using plastic tubing with a vacuum pump increased as the vacuum level was increased. Sap volumes collected at the 10- and 15-inch mercury vacuum levels were statistically significantly higher than volumes collected at the 5-inch level. Although the 15-inch vacuum yielded more sap than the 10-inch vacuum, the difference was not...

  10. Outgassing of solid material into vacuum thermal insulation spaces

    NASA Technical Reports Server (NTRS)

    Wang, Pao-Lien

    1994-01-01

    Many cryogenic storage tanks use vacuum between inner and outer tank for thermal insulation. These cryogenic tanks also use a radiation shield barrier in the vacuum space to prevent radiation heat transfer. This shield is usually constructed by using multiple wraps of aluminized mylar and glass paper as inserts. For obtaining maximum thermal performance, a good vacuum level must be maintained with the insulation system. It has been found that over a period of time solid insulation materials will vaporize into the vacuum space and the vacuum will degrade. In order to determine the degradation of vacuum, the rate of outgassing of the insulation materials must be determined. Outgassing rate of several insulation materials obtained from literature search were listed in tabular form.

  11. High-resolution imaging of Saturn's main rings during the Cassini Ring-Grazing Orbits and Grand Finale

    NASA Astrophysics Data System (ADS)

    Tiscareno, M. S.

    2017-12-01

    Cassini is ending its spectacular 13-year mission at Saturn with a two-part farewell, during which it has obtained the sharpest and highest-fidelity images ever taken of Saturn's rings. From December 2016 to April 2017, the spacecraft executed 20 near-polar orbits that passed just outside the outer edge of the main rings; these "Ring-Grazing Orbits" provided the mission's best viewing of the A and F rings and the outer B ring. From April to September 2017, the spacecraft is executing 22 near-polar orbits that pass between the innermost D ring and the planet's clouds; this "Grand Finale" provides the mission's best viewing of the C and D rings and the inner B ring. 1) Clumpy BeltsClumpy structure called "straw" was previously observed in parts of the main rings [Porco et al. 2005, Science]. New images show this structure with greater clarity. More surprisingly, new images reveal strong radial variations in the degree and character of clumpiness, which are probably an index for particle properties and interactions. Belts with different clumpiness characteristics are often adjacent to each other and not easily correlated with other ring characteristics. 2) PropellersA "propeller" is a local disturbance in the ring created by an embedded moon [Tiscareno et al. 2006, Nature; 2010, ApJL]. Cassini has observed two classes of propellers: small propellers that swarm in the "Propeller Belts" of the mid-A ring, and "Giant Propellers" whose individual orbits can be tracked in the outer A ring. Both are shown in unprecedented detail in new images. Targeted flybys of Giant Propellers were executed on both the lit and unlit sides of the ring (see figure), yielding enhanced ability to convert brightness to optical depth and surface density. 3) Impact Ejecta CloudsBeing a large and delicate system, Saturn's rings function as a detector of their planetary environment. Cassini images of impact ejecta clouds in the rings previously constrained the population of decimeter

  12. Unfocused F Ring

    NASA Image and Video Library

    2007-04-02

    The F ring dissolves into a fuzzy stream of particles -- rather different from its usual appearance of a narrow, bright core flanked by dimmer ringlets. Also notable here is the bright clump of material that flanks the ring core

  13. An Instability in Narrow Planetary Rings

    NASA Astrophysics Data System (ADS)

    Weiss, J. W.; Stewart, G. R.

    2003-08-01

    We will present our work investigating the behavior of narrow planetary rings with low dispersion velocities. Such narrow a ring will be initially unstable to self-gravitational collapse. After the collapse, the ring is collisionally very dense. At this stage, it is subject to a new instability. Waves appear on the inner and outer edges of the ring within half of an orbital period. The ring then breaks apart radially, taking approximately a quarter of an orbital period of do so. As clumps of ring particles expand radially away from the dense ring, Kepler shear causes these clumps to stretch out azimuthally, and eventually collapse into a new set of dense rings. Small-scale repetitions of the original instability in these new rings eventually leads to a stabilized broad ring with higher dispersion velocities than the initial ring. Preliminary results indicate that this instability may be operating on small scales in broad rings in the wake-like features seen by Salo and others. Some intriguing properties have been observed during this instability. The most significant is a coherence in the epicyclic phases of the particles. Both self-gravity and collisions in the ring operated to create and enforce this coherence. The coherence might also be responsible for the instability to radial expansion. We also observe that guiding centers of the particles do not migrate to the center of the ring during the collapse phase of the ring. In fact, guiding centers move radially away from the core of the ring during this phase, consistent with global conservation of angular momentum. We will show the results of our simulations to date, including movies of the evolution of various parameters. (Audiences members wanting popcorn are advised to bring their own.) This work is supported by a NASA Graduate Student Research Program grant and by the Cassini mission.

  14. The Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.

    2009-01-01

    The jumping ring experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the rings and their metallurgical state. In general, aluminium rings are…

  15. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  16. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, G.W.; Bushman, J.F.; Alger, T.W.

    1996-07-23

    A vacuum housing and pumping system is described for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof. 7 figs.

  17. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, Gerald W.; Bushman, John F.; Alger, Terry W.

    1996-01-01

    A vacuum housing and pumping system for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof.

  18. Viability of Cladosporium herbarum spores under 157 nm laser and vacuum ultraviolet irradiation, low temperature (10 K) and vacuum

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sarantopoulou, E., E-mail: esarant@eie.gr; Stefi, A.; Kollia, Z.

    Ultraviolet photons can damage microorganisms, which rarely survive prolonged irradiation. In addition to the need for intact DNA, cell viability is directly linked to the functionality of the cell wall and membrane. In this work, Cladosporium herbarum spore monolayers exhibit high viability (7%) when exposed to 157 nm laser irradiation (412 kJm⁻²) or vacuum-ultraviolet irradiation (110–180 nm) under standard pressure and temperature in a nitrogen atmosphere. Spore viability can be determined by atomic-force microscopy, nano-indentation, mass, μ-Raman and attenuated reflectance Fourier-transform far-infrared spectroscopies and DNA electrophoresis. Vacuum ultraviolet photons cause molecular damage to the cell wall, but radiation resistance inmore » spores arises from the activation of a photon-triggered signaling reaction, expressed via the exudation of intracellular substances, which, in combination with the low penetration depth of vacuum-ultraviolet photons, shields DNA from radiation. Resistance to phototoxicity under standard conditions was assessed, as was resistance to additional environmental stresses, including exposure in a vacuum, under different rates of change of pressure during pumping time and low (10 K) temperatures. Vacuum conditions were far more destructive to spores than vacuum-ultraviolet irradiation, and UV-B photons were two orders of magnitude more damaging than vacuum-ultraviolet photons. The viability of irradiated spores was also enhanced at 10 K. This work, in addition to contributing to the photonic control of the viability of microorganisms exposed under extreme conditions, including decontamination of biological warfare agents, outlines the basis for identifying bio-signaling in vivo using physical methodologies.« less

  19. Wavelength-tunable optical ring resonators

    DOEpatents

    Watts, Michael R [Albuquerque, NM; Trotter, Douglas C [Albuquerque, NM; Young, Ralph W [Albuquerque, NM; Nielson, Gregory N [Albuquerque, NM

    2009-11-10

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  20. Wavelength-tunable optical ring resonators

    DOEpatents

    Watts, Michael R [Albuquerque, NM; Trotter, Douglas C [Albuquerque, NM; Young, Ralph W [Albuquerque, NM; Nielson, Gregory N [Albuquerque, NM

    2011-07-19

    Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

  1. Helmet latching and attaching ring

    NASA Technical Reports Server (NTRS)

    Chase, E. W.; Viikinsalo, S. J. (Inventor)

    1970-01-01

    A neck ring releasably secured to a pressurized garment carries an open-ended ring normally in the engagement position fitted into an annular groove and adapted to fit into a complementary annular groove formed in a helmet. Camming means formed on the inner surface at the end of the helmet engages the open-ended ring to retract the same and allow for one motion donning even when the garment is pressurized. A projection on the end of the split ring is engageable to physically retract the split ring.

  2. A-ring Propeller

    NASA Image and Video Library

    2010-08-26

    A propeller-shaped structure, created by an unseen moon, can be seen in Saturn A ring and looks like a small, dark line interrupting the bright surrounding ring material in the upper left of this image taken by NASA Cassini spacecraft.

  3. Splinters of Rings

    NASA Image and Video Library

    2009-12-28

    Saturn shadow interrupts the planet rings, leaving just thin slivers of the rings visible in this image, which shows a pair of the planet small moons. Helene is in the center top of the image, Epimetheus is in the lower right.

  4. Residual hormone levels in used contraceptive rings as a measurement of adherence to vaginal ring use.

    PubMed

    Haaland, Richard E; Holder, Angela; Evans-Strickfaden, Tammy; Nyagol, Beatrice; Makanga, Mumbi; Oyaro, Boaz; Humwa, Felix; Williams, Tiffany; McLellan-Lemal, Eleanor; Desai, Mitesh; Huey, Michael J

    2017-06-01

    This study sought to measure residual contraceptive hormone levels in vaginal rings as an adherence marker for monitoring product use in clinical trials. Residual etonogestrel and ethinyl estradiol levels from used NuvaRings® of 26 self-reported adherent women enrolled in a clinical trial of vaginal ring acceptability were compared to those from 16 women who used NuvaRing® as their contraceptive choice. Twenty-one (81%) clinical trial rings had contraceptive hormone levels within the range of those used as a contraceptive choice. Five returned rings had unused or discordant levels of residual contraceptive hormones. Residual vaginal ring drug levels could help assess adherence in clinical trials. Published by Elsevier Inc.

  5. Main Vacuum Technical Issues of Evacuated Tube Transportation

    NASA Astrophysics Data System (ADS)

    Zhang, Y. P.; Li, S. S.; Wang, M. X.

    In the future, Evacuated Tube Transportation (ETT) would be built and faster than jets. ETT tube with diameter 2∼4m and length over 1000 km will be the largest scale vacuum equipment on earth. This paper listed some main vacuum technical issues to be solved in ETT as follow. How to build ultra-large-scale vacuum chamber like ETT tube with low cost and high reliability? How to pump gas out off the ETT tube in short time? How to release heat or reduce temperature in the vacuum tube? Hot to avoid vacuum electricity discharge? How to manufacture vehicles with airproof shells and equip the life support system? How to detect leakage and find leakage position efficiently and fast as possible? Some relative solutions and suggestions are put up.

  6. Vacuum deposition and curing of liquid monomers apparatus

    DOEpatents

    Affinito, John D.

    1996-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  7. Development of a MEMS-Scale Turbomachinery Based Vacuum Pump

    DTIC Science & Technology

    2012-06-01

    MEMS -SCALE TURBOMACHINERY BASED VACUUM PUMP by Michael J. Shea June 2012 Thesis Advisor: Anthony J. Gannon Second Reader...June 2012 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Development of a MEMS -Scale Turbomachinery Based Vacuum Pump 5...to develop a MEMS scale turbomachinery based vacuum pump. This would allow very high vacuum to be drawn for handheld mass spectroscopy. This

  8. Vacuum system for the SAMURAI spectrometer

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Otsu, H.; Kobayashi, T.; Kubo, T.; Motobayashi, T.; Sato, H.; Yoneda, K.

    2013-12-01

    The first commissioning experiment of the SAMURAI spectrometer and its beam line was performed in March, 2012. The vacuum system for the SAMURAI spectrometer includes its beam line and the SAMURAI vacuum chamber with the windows for detecting neutrons and charged particles. The window for neutrons was made of stainless steel with a thickness of 3 mm and was designed with a shape of partial cylinder to support itself against the atmospheric pressure. The window for charged particles was of the combination of Kevlar and Mylar with the thickness of 280 and 75 μm, respectively. The pressure in the vacuum system was at a few Pa throughout the commissioning experiment.

  9. Moving characteristics of electrodes for vacuum circuit breaker

    NASA Astrophysics Data System (ADS)

    Yuan, Shun; Wang, Jimei

    1994-05-01

    This paper analyzes the effect of the gap of electrodes on the state of vacuum arc by experiment and theory. And the model of vacuum arc is set up. The optimal gap can be deduced from controlling the vacuum arc to be diffusion state, in order to get the optimal moving characteristics of electrodes.

  10. Three stage vacuum system for ultralow temperature installation

    NASA Astrophysics Data System (ADS)

    Das, N. K.; Pradhan, J.; Naser, Md Z. A.; Mandal, B. Ch; Roy, A.; Kumar, P.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    We use a three stage vacuum system for developing a dilution fridge at VECC, Kolkata. We aim at achieving a cooling power of 20μW at 100mK for various experiments especially in the field of condensed matter and nuclear physics. The system is essentially composed of four segments-bath cryostat, vacuum system, dilution insert and 3He circulation circuit. Requirement of vacuum system at different stages are different. The vacuum system for cryostat and for internal vacuum chamber located within the helium bath is a common turbo molecular pump backed by scroll pump as to maintain a vacuum ~10-6mbar. For bringing down the temperature of the helium evaporator, we use a high throughput Roots pump backed by a dry pump. The pumping system for 3He distillation chamber (still) requires a high pumping speed, so a turbo drag pump backed by a scroll pump has been installed. As the fridge use precious 3He gas for operation, the entire system has been made to be absolutely leak proof with respect to the 3He gas.

  11. Carbon nanotubes based vacuum gauge

    NASA Astrophysics Data System (ADS)

    Rudyk, N. N.; Il'in, O. I.; Il'ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.

    2017-11-01

    We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

  12. Saturn Ring-Plane Crossing, may 1995

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda

    1995-07-01

    In 1995-1996, the Earth and the Sun will pass through Saturn's ring plane. The Earth will pass through 3 times (22 May 1995, 10 August 1995, 11 Feb 1996), and the Sun will pass through once (19 November 1995). All but the 11 Feb 1996 event will be visible from HST. During the crossings of the Earth through Saturn's ring plane, the rings will become very thin and dark. By monitoring the brightness of the rings as they become very thin, we will be able to determine the time of ring-plane crossing and the residual brightness of the rings at this time. The time of the ring- plane crossing will place additional constraints on the precession rate of Saturn's pole. The recent occultations by Saturn's rings have produced a measurement of this value, but it is not known very well (French et al., 1993; Bosh, 1994; Elliot et al., 1993). A measure of the brightness of the rings in their edge-on configuration, combined with photometric properties of the rings derived from early calibration observations will allow us to determine the thickness of the rings.

  13. The Vacuum-Compacted Regolith Gripping Mechanism and Unmanned Flights via Quad-Rotors

    NASA Technical Reports Server (NTRS)

    Scott, Rollin L.

    2014-01-01

    During the course of the Kennedy Space Center Summer Internship, two main experiments were performed: The Vacuum-Compacted Regolith Gripping Mechanism and Unmanned Flights via Quad-copters. The objectives of the Vacuum-Compacted Regolith Gripping Mechanism, often abbreviated as the Granular Gripper, are to exhibit Space Technology, such as a soft robotic hand, lift different apparatuses used to excavate regolith, and conserve energy while executing its intended task. The project is being conducted to test how much weight the Granular Gripper can hold. With the use of an Animatronic Robotic Hand, Arduino Uno, and other components, the system was calibrated before actually conducting the intended weight test. The maximum weight each finger could hold with the servos running, in the order of pinky, ring, middle, and index fingers, are as follows: 1.340N, 1.456 N, 0.9579 N, and 1.358 N. Using the small vacuum pump system, the maximum weight each finger could hold, in the same order, was: 4.076 N, 6.159 N, 5.454 N, and 4.052 N. The maximum torques on each of the fingers when the servos were running, in the same respective order, was: 0.0777 Nm, 0.0533 Nm, 0.0648 Nm, and 0.0532 Nm. The maximum torques on the individual fingers, when the small vacuum pump was in effect, in the same order as above, was: 0.2318 Nm, 0.3032 Nm, 0.2741 Nm, and 0.1618 Nm. In testing all the fingers with the servos running, the total weight was 5.112 N and the maximum torque on the all the fingers was 0.2515 Nm. However, when the small vacuum pump system was used, the total weight was 19.741 N and the maximum torque on the all the fingers was 0.9713 Nm. The conclusion that was drawn stated that using the small vacuum pump system proved nearly 4 times more effective when testing how much weigh the hand could hold. The resistance provided by the compacted sand in the glove allowed more weight to be held by the hand and glove. Also, when the servos turned off and the hand still retaining its

  14. The contraceptive vaginal ring, NuvaRing(®), a decade after its introduction.

    PubMed

    Roumen, Frans J M E; Mishell, Daniel R

    2012-12-01

    To review the clinical experience with the contraceptive vaginal ring (CVR, NuvaRing(®)) since its introduction over ten years ago. The literature was searched on efficacy, cycle control, safety, user preference and satisfaction of the CVR in comparison with combined oral contraceptives (COCs) and the patch, with special attention to recent developments. The ring has the same working mechanism and contraindications as COCs. Serum levels of steroids are steadier, whereas oestrogenic exposure is lower. Contraceptive efficacy is similar, as are metabolic changes. Cycle control is better, and compliance and continuation rates are equal or higher. Oestrogen-related adverse symptoms appear to be fewer, but reports on the incidence of venous thrombosis are conflicting. Expulsion of the ring is reported by 4% to 20% of women. Local adverse events are the main reason for discontinuation. Acceptability is as high as with COCs and, after structured counselling, the ring is preferred by many women to the pill or the patch. Efficacy of the CVR, and the metabolic changes and adverse events it elicits, are generally comparable to those of COCs, yet oestrogenic exposure is lower and cycle control superior. After counselling, the ring is preferred to the pill by many women.

  15. Concentric ring flywheel without expansion separators

    DOEpatents

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion.

  16. Galactic rings revisited - I. CVRHS classifications of 3962 ringed galaxies from the Galaxy Zoo 2 Database

    NASA Astrophysics Data System (ADS)

    Buta, Ronald J.

    2017-11-01

    Rings are important and characteristic features of disc-shaped galaxies. This paper is the first in a series that re-visits galactic rings with the goals of further understanding the nature of the features and for examining their role in the secular evolution of galaxy structure. The series begins with a new sample of 3962 galaxies drawn from the Galaxy Zoo 2 citizen science data base, selected because zoo volunteers recognized a ring-shaped pattern in the morphology as seen in Sloan Digital Sky Survey colour images. The galaxies are classified within the framework of the Comprehensive de Vaucouleurs revised Hubble-Sandage system. It is found that zoo volunteers cued on the same kinds of ring-like features that were recognized in the 1995 Catalogue of Southern Ringed Galaxies. This paper presents the full catalogue of morphological classifications, comparisons with other sources of classifications and some histograms designed mainly to highlight the content of the catalogue. The advantages of the sample are its large size and the generally good quality of the images; the main disadvantage is the low physical resolution that limits the detectability of linearly small rings such as nuclear rings. The catalogue includes mainly inner and outer disc rings and lenses. Cataclysmic (`encounter-driven') rings (such as ring and polar ring galaxies) are recognized in less than 1 per cent of the sample.

  17. Baryogenesis in false vacuum

    NASA Astrophysics Data System (ADS)

    Hamada, Yuta; Yamada, Masatoshi

    2017-09-01

    The null result in the LHC may indicate that the standard model is not drastically modified up to very high scales, such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops a large vacuum expectation value in the early universe, a lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with higher-dimensional operators.

  18. Comparative Evaluation of Vacuum-based Surface Sampling ...

    EPA Pesticide Factsheets

    Journal Article Following a biological contamination incident, collection of surface samples is necessary to determine the extent and level of contamination, and to deem an area safe for reentry upon decontamination. Current sampling strategies targeting Bacillus anthracis spores prescribe vacuum-based methods for rough and/or porous surfaces. In this study, four commonly-used B. anthracis spore sampling devices (vacuum socks, 37 mm 0.8 µm MCE filter cassettes, 37 mm 0.3 µm PTFE filter cassettes, and 3MTM forensic filters) were comparatively evaluated for their ability to recover surface-associated spores. The vacuum sock device was evaluated at two sampling speeds (slow and fast), resulting in five total methods evaluated. Aerosolized spores (~105 cm-2) of a surrogate Bacillus species (Bacillus atrophaeus) were allowed to settle onto three material types (concrete, carpet, and upholstery). Ten replicate samples were collected using each vacuum method, from each of the three material types. In addition, stainless steel (i.e., nonporous) surfaces inoculated simultaneously were sampled with pre-moistened wipes. Recoveries from wipes of steel surfaces were utilized to verify the inoculum, and to normalize vacuum-based recoveries across trials. Recovery (CFU cm-2) and relative recovery (vacuum recovery/wipe recovery) were determined for each method and material type. Relative recoveries were compared by one-way and three-way ANOVA. Data analysis by one-

  19. Vacuum energy from noncommutative models

    NASA Astrophysics Data System (ADS)

    Mignemi, S.; Samsarov, A.

    2018-04-01

    The vacuum energy is computed for a scalar field in a noncommutative background in several models of noncommutative geometry. One may expect that the noncommutativity introduces a natural cutoff on the ultraviolet divergences of field theory. Our calculations show however that this depends on the particular model considered: in some cases the divergences are suppressed and the vacuum energy is only logarithmically divergent, in other cases they are stronger than in the commutative theory.

  20. Sealed vacuum canister and method for pick-up and containment of material

    DOEpatents

    Stoutenburgh, Roger R.

    1996-01-01

    A vacuum canister including a housing with a sealed vacuum chamber having a predetermined vacuum pressure therein and a valve having a first port for fluid communication with the vacuum chamber and a second port for receiving at least one of a fluid and a particulate material. The valve is operable between a first position to seal the vacuum chamber and retain the predetermined vacuum within the vacuum chamber, and a second position to access the vacuum chamber to permit vacuum fluid flow through the valve from the second port into the vacuum chamber. In operation of the vacuum canister to pick up material with the valve in the second position, when the second port is located adjacent at least one of a fluid and a particulate material, is effective to displace through the valve at least one of a fluid and a particulate material into the housing. The vacuum canister is desirably suitable for picking up and containing hazardous material such as radioactive material, in which the vacuum canister includes a protective layer of lead having a predetermined thickness that is effective to shield radiation emitted from the radioactive material contained within the housing. Advantageously, the vacuum canister includes a vacuum means for establishing a predetermined vacuum pressure within the vacuum chamber.

  1. An ultra-high vacuum chamber for scattering experiments featuring in-vacuum continuous in-plane variation of the angle between entrance and exit vacuum ports

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Englund, Carl-Johan; Agåker, Marcus, E-mail: marcus.agaker@physics.uu.se; Fredriksson, Pierre

    2015-09-15

    A concept that enables in-vacuum continuous variation of the angle between two ports in one plane has been developed and implemented. The vacuum chamber allows for measuring scattering cross sections as a function of scattering angle and is intended for resonant inelastic X-ray scattering experiments. The angle between the ports can be varied in the range of 30°-150°, while the pressure change is less than 2 × 10{sup −10} mbars.

  2. Rheology modification with ring polymers

    NASA Astrophysics Data System (ADS)

    Vlassopoulos, Dimitris

    It is now established that experimental unconcatenated ring polymers can be purified effectively by means of fractionation at the critical condition. For molecular weights well above the entanglement threshold, purified rings relax stress via power-law (with an exponent of about -0.4), sharply departing from their linear counterparts. Experimental results are in harmony with modeling predictions and simulations. Here, we present results from recent interdisciplinary efforts and discuss two challenges: (i) the nonlinear shear rheology of purified ring melts is also very different from that of unlinked chains. Whereas the latter exhibit features that can be explained, to a first approach, in the framework in the tube model, the former behave akin to unentangled chains with finite extensibility and exhibit much small deformation at steady state. (ii) blends of rings and linear polymers exhibit unique features in different regimes: The addition of minute amounts of linear chains drastically affects ring dynamics. This relates to ring purity and the ability of unlinked linear chains to thread rings. With the help of simulations, it is possible to rationalize the observed surprisingly slow viscoelastic relaxation, which is attributed to ring-linear and ring-ring penetrations. On the other hand, adding small amounts of rings to linear polymers of different molecular weights influences their linear and nonlinear rheology in an unprecedented way. The blend viscosity exceeds that of the slower component (linear) in this non-interacting mixture, and its dependencies on composition and molecular weight ratio are examined, whereas the role of molecular architecture is also addressed. Consequently, closing the ends of a linear chain can serve as a powerful means for molecular manipulation of its rheology. This presentation reflects collaborative efforts with S. Costanzo, Z-C. Yan, R. Pasquino, M. Kaliva, S. Kamble, Y. Jeong, P. Lutz, J. Allgaier, T. Chang, D. Talikis, V

  3. Overview of Fabrication Techniques and Lessons Learned with Accelerator Vacuum Windows

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ader, C. R.; McGee, M. W.; Nobrega, L. E.

    Vacuum thin windows have been used in Fermilab's accelerators for decades and typically have been overlooked in terms of their criticality and fragility. Vacuum windows allow beam to pass through while creating a boundary between vacuum and air or high vacuum and low vacuum areas. The design of vacuum windows, including Titanium and Beryllium windows, will be discussed as well as fabrication, testing, and operational concerns. Failure of windows will be reviewed as well as safety approaches to mitigating failures and extending the lifetimes of vacuum windows. Various methods of calculating the strengths of vacuum windows will be explored, includingmore » FEA.« less

  4. Safety shield for vacuum/pressure-chamber windows

    NASA Technical Reports Server (NTRS)

    Shimansky, R. A.; Spencer, R.

    1980-01-01

    Optically-clear shatter-resistant safety shield protects workers from implosion and explosion of vacuum and pressure windows. Plastic shield is inexpensive and may be added to vacuum chambers, pressure chambers, and gas-filling systems.

  5. Vacuum tool manipulator

    DOEpatents

    Zollinger, W.T.

    1993-11-23

    Apparatus for manipulating a vacuum hose in a reactor vessel comprises a housing with two opposing openings, an arm carried by the housing and deployable from a stowed position essentially completely within the housing to an extended position where the arm extends through the two openings in a generally horizontal position. The arm preferably has a two-fingered gripping device for gripping the vacuum hose but may carry a different end effector such as a grinding wheel. The fingers are opened and closed by one air cylinder. A second air cylinder extends the device. A third air cylinder within the housing pivotally pulls the opposing end of the arm into the housing via a pivoting member pivotally connected between the third air cylinder shaft and the arm. 6 figures.

  6. The structure of Jupiter’s main ring from New Horizons: A comparison with other ring-moon systems

    NASA Astrophysics Data System (ADS)

    Chancia, Robert; Hedman, Matthew

    2018-04-01

    During New Horizon’s Jupiter flyby in 2007, the Long-Range Reconnaissance Imager (LORRI) took several images of the planet’s main ring. The data set contains two extended image-movies of the main ring, along with several brief observations at varying ring azimuths, and a small set of high phase angle images. Thus far, the only published work on the New Horizons Jupiter rings data set found seven bright clumps with sub-km equivalent radii embedded in the main ring (Showalter et al. 2007 Science). In this work, we searched the inner region of the main ring for any structures that might be perturbed at the 3:2 resonances with the rotation of Jupiter’s magnetic field or massive storms. We also examined the structure of the outer main ring in order to assess how it is shaped by the small moons Metis and Adrastea. Some of the features seen in Jupiter’s main ring are similar to those found in other dusty rings around Saturn, Uranus, and Neptune. By comparing these different rings, we can gain a better understanding of how small moons sculpt tenuous rings.

  7. Proton velocity ring-driven instabilities and their dependence on the ring speed: Linear theory

    NASA Astrophysics Data System (ADS)

    Min, Kyungguk; Liu, Kaijun; Gary, S. Peter

    2017-08-01

    Linear dispersion theory is used to study the Alfvén-cyclotron, mirror and ion Bernstein instabilities driven by a tenuous (1%) warm proton ring velocity distribution with a ring speed, vr, varying between 2vA and 10vA, where vA is the Alfvén speed. Relatively cool background protons and electrons are assumed. The modeled ring velocity distributions are unstable to both the Alfvén-cyclotron and ion Bernstein instabilities whose maximum growth rates are roughly a linear function of the ring speed. The mirror mode, which has real frequency ωr=0, becomes the fastest growing mode for sufficiently large vr/vA. The mirror and Bernstein instabilities have maximum growth at propagation oblique to the background magnetic field and become more field-aligned with an increasing ring speed. Considering its largest growth rate, the mirror mode, in addition to the Alfvén-cyclotron mode, can cause pitch angle diffusion of the ring protons when the ring speed becomes sufficiently large. Moreover, because the parallel phase speed, v∥ph, becomes sufficiently small relative to vr, the low-frequency Bernstein waves can also aid the pitch angle scattering of the ring protons for large vr. Potential implications of including these two instabilities at oblique propagation on heliospheric pickup ion dynamics are discussed.

  8. Extreme-UV lithography vacuum chamber zone seal

    DOEpatents

    Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

    2001-01-01

    Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

  9. Extreme-UV lithography vacuum chamber zone seal

    DOEpatents

    Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

    2003-04-08

    Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

  10. Extreme-UV lithography vacuum chamber zone seal

    DOEpatents

    Haney, Steven J.; Herron, Donald Joe; Klebanoff, Leonard E.; Replogle, William C.

    2003-04-15

    Control of particle contamination on the reticle and carbon contamination of optical surfaces in photolithography systems can be achieved by the establishment of multiple pressure zones in the photolithography systems. The different zones will enclose the reticle, projection optics, wafer, and other components of system. The system includes a vacuum apparatus that includes: a housing defining a vacuum chamber; one or more metrology trays situated within the vacuum chamber each of which is supported by at least one support member, wherein the tray separates the vacuum chamber into a various compartments that are maintained at different pressures; and conductance seal devices for adjoining the perimeter of each tray to an inner surface of the housing wherein the tray is decoupled from vibrations emanating from the inner surface of the housing.

  11. Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

    NASA Astrophysics Data System (ADS)

    Husain, Riyasat; Ghodke, A. D.

    2017-08-01

    Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

  12. Nuclear-matter radius studies from 58Ni(α ,α ) experiments at the GSI Experimental Storage Ring with the EXL facility

    NASA Astrophysics Data System (ADS)

    Zamora, J. C.; Aumann, T.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, Th.; Kuilman, M.; Litvinov, S.; Litvinov, Yu. A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; von Schmid, M.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zenihiro, J.

    2017-09-01

    A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of 58Ni. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored 58Ni beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered α -recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of 58Ni with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

  13. Vacuum deposition and curing of liquid monomers apparatus

    DOEpatents

    Affinito, J.D.

    1996-08-20

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface. 3 figs.

  14. Edge-on View of Saturn's Rings

    NASA Technical Reports Server (NTRS)

    1996-01-01

    TOP - This is a NASA Hubble Space Telescope snapshot of Saturn with its rings barely visible. Normally, astronomers see Saturn with its rings tilted. Earth was almost in the plane of Saturn's rings, thus the rings appear edge-on.

    In this view, Saturn's largest moon, Titan, is casting a shadow on Saturn. Titan's atmosphere is a dark brown haze. The other moons appear white because of their bright, icy surfaces. Four moons - from left to right, Mimas, Tethys, Janus, and Enceladus - are clustered around the edge of Saturn's rings on the right. Two other moons appear in front of the ring plane. Prometheus is on the right edge; Pandora, on the left. The rings also are casting a shadow on Saturn because the Sun was above the ring plane.

    BOTTOM - This photograph shows Saturn with its rings slightly tilted. The moon called Dione, on the lower right, is casting a long, thin shadow across the whole ring system due to the setting Sun on the ring plane. The moon on the upper left of Saturn is Tethys.

    Astronomers also are studying the unusual appearance of Saturn's rings. The bottom image displays a faint, narrow ring, the F-ring just outside the main ring, which normally is invisible from Earth. Close to the edge of Saturn's disk, the front section of rings seem brighter and more yellow than the back due to the additional lumination by yellowish Saturn.

    The color images were assembled from separate exposures taken August 6 (top) and November 17 (bottom), 1995 with the Wide Field Planetary Camera-2.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

    This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  15. Apse-Alignment of the Uranian Rings

    NASA Technical Reports Server (NTRS)

    Mosqueira, I.; Estrada, P. R.

    2000-01-01

    An explanation of the dynamical mechanism for apse-alignment of the eccentric Uranian rings is necessary before observations can be used to determine properties such as ring masses, particle sizes, and elasticities. The leading model relies on the ring self-gravity to accomplish this task, yet it yields equilibrium masses which are not in accord with Voyager radio measurements. We explore possible solutions such that the self-gravity and the collisional terms are both involved in the process of apse-alignment. We consider limits that correspond to a hot and a cold ring, and show that pressure terms may play a significant role in the equilibrium conditions for the narrow Uranian rings. In the cold ring case, where the scale height of the ring near periapse is comparable to the ring particle size, we introduce a new pressure correction pertaining to a region of the ring where the particles are locked in their relative positions and jammed against their neighbors, and the velocity dispersion is so low that the collisions are nearly elastic. In this case, we find a solution such that the ring self-gravity maintains apse-alignment against both differential precession (m = 1 mode) and the fluid pressure. We apply this model to the Uranian alpha ring, and show that, compared to the previous self-gravity model, the mass estimate for this ring increases by an order of magnitude. In the case of a hot ring, where the scale height can reach a value as much as fifty times larger than a particle size, we find velocity dispersion profiles that result in pressure forces which act in such a way as to alter the ring equilibrium conditions, again leading to a ring mass increase of an order of magnitude; however, such a velocity dispersion profile would require a different mechanism than is currently envisioned for establishing heating/cooling balance in a finite-sized, inelastic particle ring. Finally, we introduce an important correction to the model of Chiang and Goldreich.

  16. Simulating the Smallest Ring World of Chariklo

    NASA Astrophysics Data System (ADS)

    Michikoshi, Shugo; Kokubo, Eiichiro

    2017-03-01

    A ring system consisting of two dense narrow rings has been discovered around Centaur Chariklo. The existence of these rings around a small object poses various questions about their origin, stability, and lifetime. In order to understand the nature of Chariklo’s rings, we perform global N-body simulations of the self-gravitating collisional particle rings for the first time. We find that Chariklo should be denser than the ring material in order to avoid the rapid diffusion of the rings. If Chariklo is denser than the ring material, fine spiral structures called self-gravity wakes occur in the inner ring. These wakes accelerate the viscous spreading of the ring significantly and typically occur on timescales of about 100 {years} for m-sized ring particles, which is considerably shorter than the timescales suggested in previous studies. The existence of these narrow rings implies smaller ring particles or the existence of shepherding satellites.

  17. Recent Simulation Results on Ring Current Dynamics Using the Comprehensive Ring Current Model

    NASA Technical Reports Server (NTRS)

    Zheng, Yihua; Zaharia, Sorin G.; Lui, Anthony T. Y.; Fok, Mei-Ching

    2010-01-01

    Plasma sheet conditions and electromagnetic field configurations are both crucial in determining ring current evolution and connection to the ionosphere. In this presentation, we investigate how different conditions of plasma sheet distribution affect ring current properties. Results include comparative studies in 1) varying the radial distance of the plasma sheet boundary; 2) varying local time distribution of the source population; 3) varying the source spectra. Our results show that a source located farther away leads to a stronger ring current than a source that is closer to the Earth. Local time distribution of the source plays an important role in determining both the radial and azimuthal (local time) location of the ring current peak pressure. We found that post-midnight source locations generally lead to a stronger ring current. This finding is in agreement with Lavraud et al.. However, our results do not exhibit any simple dependence of the local time distribution of the peak ring current (within the lower energy range) on the local time distribution of the source, as suggested by Lavraud et al. [2008]. In addition, we will show how different specifications of the magnetic field in the simulation domain affect ring current dynamics in reference to the 20 November 2007 storm, which include initial results on coupling the CRCM with a three-dimensional (3-D) plasma force balance code to achieve self-consistency in the magnetic field.

  18. Compressible Vortex Ring

    NASA Astrophysics Data System (ADS)

    Elavarasan, Ramasamy; Arakeri, Jayawant; Krothapalli, Anjaneyulu

    1999-11-01

    The interaction of a high-speed vortex ring with a shock wave is one of the fundamental issues as it is a source of sound in supersonic jets. The complex flow field induced by the vortex alters the propagation of the shock wave greatly. In order to understand the process, a compressible vortex ring is studied in detail using Particle Image Velocimetry (PIV) and shadowgraphic techniques. The high-speed vortex ring is generated from a shock tube and the shock wave, which precedes the vortex, is reflected back by a plate and made to interact with the vortex. The shadowgraph images indicate that the reflected shock front is influenced by the non-uniform flow induced by the vortex and is decelerated while passing through the vortex. It appears that after the interaction the shock is "split" into two. The PIV measurements provided clear picture about the evolution of the vortex at different time interval. The centerline velocity traces show the maximum velocity to be around 350 m/s. The velocity field, unlike in incompressible rings, contains contributions from both the shock and the vortex ring. The velocity distribution across the vortex core, core diameter and circulation are also calculated from the PIV data.

  19. Microbial analysis of meatballs cooled with vacuum and conventional cooling.

    PubMed

    Ozturk, Hande Mutlu; Ozturk, Harun Kemal; Koçar, Gunnur

    2017-08-01

    Vacuum cooling is a rapid evaporative cooling technique and can be used for pre-cooling of leafy vegetables, mushroom, bakery, fishery, sauces, cooked food, meat and particulate foods. The aim of this study was to apply the vacuum cooling and the conventional cooling techniques for the cooling of the meatball and to show the vacuum pressure effect on the cooling time, the temperature decrease and microbial growth rate. The results of the vacuum cooling and the conventional cooling (cooling in the refrigerator) were compared with each other for different temperatures. The study shows that the conventional cooling was much slower than the vacuum cooling. Moreover, the microbial growth rate of the vacuum cooling was extremely low compared with the conventional cooling. Thus, the lowest microbial growth occurred at 0.7 kPa and the highest microbial growth was observed at 1.5 kPa for the vacuum cooling. The mass loss ratio for the conventional cooling and vacuum cooling was about 5 and 9% respectively.

  20. Recycling of waste lead storage battery by vacuum methods.

    PubMed

    Lin, Deqiang; Qiu, Keqiang

    2011-07-01

    Waste lead storage battery is the most important recyclable lead material not only in various European and other OECD countries but also in China. Pollution control of lead has become the focus of people's attention in the world. A vacuum process for recycling waste lead storage battery was developed in this work. The experimental results showed that all the valuable materials in waste lead storage battery could be satisfactorily recycled by vacuum technologies. The vacuum melting of lead grids and the vacuum reduction of lead pastes produce the lead bullion with the direct recovery ratio of 96.29% and 98.98%, respectively. The vacuum pyrolysis of plastics can produce pyrolysis oil with yield of more than 93 wt.%. These vacuum recycling technologies offer improvements in metallurgical and environmental performance. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Window-assisted nanosphere lithography for vacuum micro-nano-electronics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Nannan; Institute of Electronic Engineering, Chinese Academy of Engineering Physics, Mianyang, 621900; Pang, Shucai

    2015-04-15

    Development of vacuum micro-nano-electronics is quite important for combining the advantages of vacuum tubes and solid-state devices but limited by the prevailing fabricating techniques which are expensive, time consuming and low-throughput. In this work, window-assisted nanosphere lithography (NSL) technique was proposed and enabled the low-cost and high-efficiency fabrication of nanostructures for vacuum micro-nano-electronic devices, thus allowing potential applications in many areas. As a demonstration, we fabricated high-density field emitter arrays which can be used as cold cathodes in vacuum micro-nano-electronic devices by using the window-assisted NSL technique. The details of the fabricating process have been investigated. This work provided amore » new and feasible idea for fabricating nanostructure arrays for vacuum micro-nano-electronic devices, which would spawn the development of vacuum micro-nano-electronics.« less

  2. Symmetrical collision of multiple vortex rings

    NASA Astrophysics Data System (ADS)

    Hernández, R. H.; Reyes, T.

    2017-10-01

    In this work, we investigate the motion, interaction, and simultaneous collision between many initially stable vortex rings arranged symmetrically in two initial configurations, three and six rings making an angle of 60 and 120° between their straight path lines, respectively. We report results for laminar vortex rings in air obtained through numerical simulations of the ring velocity, pressure, and vorticity fields, both in free flight and during the entire collision. Each collision was studied for small Reynolds numbers R e <1 03 based on both the self-induced velocity and diameter of the ring. The case of three rings produces secondary vortical structures formed by laterally expanding dipolar arms with top and bottom secondary vortex rings. The case of six colliding rings produces, as secondary structures, two big rings moving in opposite directions, a process that reminds us of the head-on collision of two rings [T. T. Lim and T. B. Nickels, "Instability and reconnection in the head-on collision of two vortex rings," Nature 357, 225-227 (1992)] under a hypothetical time reversal transformation. Both collisions display a characteristic kinetic energy evolution where mean collision stages can be identified within the range of Reynolds numbers investigated here.

  3. Sealed vacuum canister and method for pick-up and containment of material

    DOEpatents

    Stoutenburgh, R.R.

    1996-02-13

    A vacuum canister is described including a housing with a sealed vacuum chamber having a predetermined vacuum pressure therein and a valve having a first port for fluid communication with the vacuum chamber and a second port for receiving at least one of a fluid and a particulate material. The valve is operable between a first position to seal the vacuum chamber and retain the predetermined vacuum within the vacuum chamber, and a second position to access the vacuum chamber to permit vacuum fluid flow through the valve from the second port into the vacuum chamber. The vacuum canister, in the operation to pick up material with the valve in the second position, when the second port is located adjacent at least one of a fluid and a particulate material, is effective to displace through the valve at least one of a fluid and a particulate material into the housing. The vacuum canister is desirably suitable for picking up and containing hazardous material such as radioactive material, in which the vacuum canister includes a protective layer of lead having a predetermined thickness that is effective to shield radiation emitted from the radioactive material contained within the housing. Advantageously, the vacuum canister includes a vacuum means for establishing a predetermined vacuum pressure within the vacuum chamber. 6 figs.

  4. Vacuum transfer system increases sugar maple sap yield

    Treesearch

    Russell S. Walters

    1978-01-01

    Yields of sugar maple sap collected from three plastic pipeline systems by gravity, vacuum pump, and a vacuum pump with a transfer tank were compared during 2 years in northern Vermont. The transfer system yielded 27 percent more sap one year and 17 percent more the next year. Higher vacuum levels at the tapholes were observed in the transfer system.

  5. Vacuum plasma coatings for turbine blades

    NASA Technical Reports Server (NTRS)

    Holmes, R. R.

    1985-01-01

    Turbine blades, vacuum plasma spray coated with NiCrAlY, CoCrAlY or NiCrAlY/Cr2O3, were evaluated and rated superior to standard space shuttle main engine (SSME) coated blades. Ratings were based primarily on 25 thermal cycles in the MSFC Burner Rig Tester, cycling between 1700 F (gaseous H2) and -423 F (liquid H2). These tests showed no spalling on blades with improved vacuum plasma coatings, while standard blades spalled. Thermal barrier coatings of ZrO2, while superior to standard coatings, lacked the overall performance desired. Fatigue and tensile specimens, machined from MAR-M-246(Hf) test bars identical to the blades were vacuum plasma spray coated, diffusion bond treated, and tested to qualify the vacuum plasma spray process for flight hardware testing and application. While NiCrAlY/Cr2O3 offers significant improvement over standard coatings in durability and thermal protection, studies continue with an objective to develop coatings offering even greater improvements.

  6. Self contained, independent, in-vacuum spinner motor

    DOEpatents

    Ayers, Marion J.

    2002-01-01

    An independent, self contained apparatus for operation within a vacuum chamber. A sealed enclosure is located in the chamber. The enclosure contains its own atmosphere independent of the vacuum in the chamber. A motor, power unit, and controls are located entirely within the enclosure. They do not have a direct structural connection outside of the enclosure in any way that would effect the atmosphere within the enclosure. The motor, power unit, and controls drive a spinner plate located outside the enclosure but within the vacuum chamber.

  7. Smoke Ring Physics

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2011-01-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampere's law in an introductory physics course. We discuss these common features. (Contains 7 figures.)

  8. Microscale Digital Vacuum Electronic Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  9. Controlled release of metronidazole from composite poly-ε-caprolactone/alginate (PCL/alginate) rings for dental implants.

    PubMed

    Lan, Shih-Feng; Kehinde, Timilehin; Zhang, Xiangming; Khajotia, Sharukh; Schmidtke, David W; Starly, Binil

    2013-06-01

    Dental implants provide support for dental crowns and bridges by serving as abutments for the replacement of missing teeth. To prevent bacterial accumulation and growth at the site of implantation, solutions such as systemic antibiotics and localized delivery of bactericidal agents are often employed. The objective of this study was to demonstrate a novel method of controlled localized delivery of antibacterial agents to an implant site using a biodegradable custom fabricated ring. The study involved incorporating a model antibacterial agent (metronidazole) into custom designed poly-ε-caprolactone/alginate (PCL/alginate) composite rings to produce the intended controlled release profile. The rings can be designed to fit around the body of any root form dental implants of various diameters, shapes and sizes. In vitro release studies indicate that pure (100%) alginate rings exhibited an expected burst release of metronidazole in the first few hours, whereas Alginate/PCL composite rings produced a medium burst release followed by a sustained release for a period greater than 4 weeks. By varying the PCL/alginate weight ratios, we have shown that we can control the amount of antibacterial agents released to provide the minimal inhibitory concentration (MIC) needed for adequate protection. The fabricated composite rings have achieved a 50% antibacterial agent release profile over the first 48 h and the remaining amount slowly released over the remainder of the study period. The PCL/alginate agent release characteristic fits the Ritger-Peppas model indicating a diffusion-based mechanism during the 30-day study period. The developed system demonstrates a controllable drug release profile and the potential for the ring to inhibit bacterial biofilm growth for the prevention of diseases such as peri-implantitis resulting from bacterial infection at the implant site. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  10. Instrument for measurement of vacuum in sealed thin wall packets

    DOEpatents

    Kollie, T.G.; Thacker, L.H.; Fine, H.A.

    1995-04-18

    An instrument is disclosed for the measurement of vacuum within sealed packets, the packets having a wall that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head for placement against the deformable wall of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall with this deformation or lift monitored by the application of light as via a bifurcated light pipe. Retro-reflected light through the light pipe is monitored with a photo detector. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet. In a preferred embodiment a vacuum plate is placed beneath the packet to ensure that no deformation occurs on the reverse surface of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head. 4 figs.

  11. Ringed Structures of the HD 163296 Protoplanetary Disk Revealed by ALMA

    NASA Astrophysics Data System (ADS)

    Isella, Andrea; Guidi, Greta; Testi, Leonardo; Liu, Shangfei; Li, Hui; Li, Shengtai; Weaver, Erik; Boehler, Yann; Carperter, John M.; De Gregorio-Monsalvo, Itziar; Manara, Carlo F.; Natta, Antonella; Pérez, Laura M.; Ricci, Luca; Sargent, Anneila; Tazzari, Marco; Turner, Neal

    2016-12-01

    We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around the Herbig Ae star HD 163296 that trace the spatial distribution of millimeter-sized particles and cold molecular gas on spatial scales as small as 25 astronomical units (A.U.). The image of the disk recorded in the 1.3 mm continuum emission reveals three dark concentric rings that indicate the presence of dust depleted gaps at about 60, 100, and 160 A.U. from the central star. The maps of the 12CO, 13CO, and C 18O J =2 -1 emission do not show such structures but reveal a change in the slope of the radial intensity profile across the positions of the dark rings in the continuum image. By comparing the observations with theoretical models for the disk emission, we find that the density of CO molecules is reduced inside the middle and outer dust gaps. However, in the inner ring there is no evidence of CO depletion. From the measurements of the dust and gas densities, we deduce that the gas-to-dust ratio varies across the disk and, in particular, it increases by at least a factor 5 within the inner dust gap compared to adjacent regions of the disk. The depletion of both dust and gas suggests that the middle and outer rings could be due to the gravitational torque exerted by two Saturn-mass planets orbiting at 100 and 160 A.U. from the star. On the other hand, the inner dust gap could result from dust accumulation at the edge of a magnetorotational instability dead zone, or from dust opacity variations at the edge of the CO frost line. Observations of the dust emission at higher angular resolution and of molecules that probe dense gas are required to establish more precisely the origins of the dark rings observed in the HD 163296 disk.

  12. Ringed Structures of the HD 163296 Protoplanetary Disk Revealed by ALMA.

    PubMed

    Isella, Andrea; Guidi, Greta; Testi, Leonardo; Liu, Shangfei; Li, Hui; Li, Shengtai; Weaver, Erik; Boehler, Yann; Carperter, John M; De Gregorio-Monsalvo, Itziar; Manara, Carlo F; Natta, Antonella; Pérez, Laura M; Ricci, Luca; Sargent, Anneila; Tazzari, Marco; Turner, Neal

    2016-12-16

    We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around the Herbig Ae star HD 163296 that trace the spatial distribution of millimeter-sized particles and cold molecular gas on spatial scales as small as 25 astronomical units (A.U.). The image of the disk recorded in the 1.3 mm continuum emission reveals three dark concentric rings that indicate the presence of dust depleted gaps at about 60, 100, and 160 A.U. from the central star. The maps of the ^{12}CO, ^{13}CO, and C^{18}O J=2-1 emission do not show such structures but reveal a change in the slope of the radial intensity profile across the positions of the dark rings in the continuum image. By comparing the observations with theoretical models for the disk emission, we find that the density of CO molecules is reduced inside the middle and outer dust gaps. However, in the inner ring there is no evidence of CO depletion. From the measurements of the dust and gas densities, we deduce that the gas-to-dust ratio varies across the disk and, in particular, it increases by at least a factor 5 within the inner dust gap compared to adjacent regions of the disk. The depletion of both dust and gas suggests that the middle and outer rings could be due to the gravitational torque exerted by two Saturn-mass planets orbiting at 100 and 160 A.U. from the star. On the other hand, the inner dust gap could result from dust accumulation at the edge of a magnetorotational instability dead zone, or from dust opacity variations at the edge of the CO frost line. Observations of the dust emission at higher angular resolution and of molecules that probe dense gas are required to establish more precisely the origins of the dark rings observed in the HD 163296 disk.

  13. Dyonic Flux Tube Structure of Nonperturbative QCD Vacuum

    NASA Astrophysics Data System (ADS)

    Chandola, H. C.; Pandey, H. C.

    We study the flux tube structure of the nonperturbative QCD vacuum in terms of its dyonic excitations by using an infrared effective Lagrangian and show that the dyonic condensation of QCD vacuum has a close connection with the process of color confinement. Using the fiber bundle formulation of QCD, the magnetic symmetry condition is presented in a gauge covariant form and the gauge potential has been constructed in terms of the magnetic vectors on global sections. The dynamical breaking of the magnetic symmetry has been shown to lead the dyonic condensation of QCD vacuum in the infrared energy sector. Deriving the asymptotic solutions of the field equations in the dynamically broken phase, the dyonic flux tube structure of QCD vacuum is explored which has been shown to lead the confinement parameters in terms of the vector and scalar mass modes of the condensed vacuum. Evaluating the charge quantum numbers and energy associated with the dyonic flux tube solutions, the effect of electric excitation of monopole is analyzed using the Regge slope parameter (as an input parameter) and an enhancement in the dyonic pair correlations and the confining properties of QCD vacuum in its dyonically condensed mode has been demonstrated.

  14. Flow Visualization Proposed for Vacuum Cleaner Nozzle Designs

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In 1995, the NASA Lewis Research Center and the Kirby Company (a major vacuum cleaner company) began negotiations for a Space Act Agreement to conduct research, technology development, and testing involving the flow behavior of airborne particulate flow behavior. Through these research efforts, we hope to identify ways to improve suction, flow rate, and surface agitation characteristics of nozzles used in vacuum cleaner nozzles. We plan to apply an advanced visualization technology, known as Stereoscopic Imaging Velocimetry (SIV), to a Kirby G-4 vacuum cleaner. Resultant data will be analyzed with a high-speed digital motion analysis system. We also plan to evaluate alternative vacuum cleaner nozzle designs. The overall goal of this project is to quantify both velocity fields and particle trajectories throughout the vacuum cleaner nozzle to optimize its "cleanability"--its ability to disturb and remove embedded dirt and other particulates from carpeting or hard surfaces. Reference

  15. Planetary rings - Theory

    NASA Technical Reports Server (NTRS)

    Borderies, Nicole

    1989-01-01

    Theoretical models of planetary-ring dynamics are examined in a brief analytical review. The mathematical description of streamlines and streamline interactions is outlined; the redistribution of angular momentum due to collisions between particles is explained; and problems in the modeling of broad, narrow, and arc rings are discussed.

  16. The Dynamics of Dense Planetary Rings.

    NASA Astrophysics Data System (ADS)

    Mosqueira, Ignacio

    1995-01-01

    We study the dynamics of a two-mode narrow ring in the case that one of the modes dominates the overall ring perturbation. We use a simple two-streamline self -gravity model, including viscosity, and shepherd satellites. As might be expected, we find that n m = 1 mode appears to be a natural end state for the rings, inasmuch as the presence of a dominant eccentric mode inhibits the growth of other modes, but the reverse is not true. Why some rings exhibit other m values only remains unexplained. Using a modified N-body code to include periodic boundary conditions in a perturbed shear flow, we investigate the role of viscosity on the dynamics of perturbed rings with optical depth tau ~ 1. In particular, we are concerned with rings such that qe = a{de over da} ne 0, where a is the semi-major axis and e is the eccentricity. We confirm the possibility that, for a sufficiently perturbed ring, the angular momentum luminosity may reverse direction with respect to the unperturbed ring (Borderies et al. 1983a). We use observationally constrained parameters for the delta and epsilon Uranian rings, as well as the outer portion of Saturn's B ring. We find that understanding the effects of viscosity for the Uranian rings requires that both local and non-local transport terms be considered if the coefficient of restitution experimentally obtained by Bridges et al. (1984) is appropriate for ring particles. We also find evidence that the criterion for viscous overstability is satisfied in the case of high optical depth rings, as originally proposed by Borderies et al. (1985), making viscous overstability a leading candidate mechanism to explain the non-axisymmetric structure present in the outer portion of Saturn's B ring. To better understand our path-code results we extend a non-local and incompressible fluid model used by Borderies et al. (1985) for dense rings. We incorporate local and non-local transport terms as well as compressibility, while retaining the same number of

  17. Planetary rings as relics of plasma proto-rings rotating in the magnetic field of a central body

    NASA Astrophysics Data System (ADS)

    Rabinovich, B.

    2007-08-01

    A possibility is discussed in accordance to hypothesis by H. Alfven, that the rings of large planets are relics of some plasma proto-rings rotating in the magnetic fields of central bodies. A finite-dimensional mathematical model of the system is synthesized using the solution of the boundary-value problem by the Boubnov - Galerkin method. The dipole magnetic field of the central body is assumed to have a small eccentricity, and the dipole axis - to be inclined at a small angle to the central body's axis of rotation which coincides with the ring's rotation axis. The proto-ring is supposed to be thin and narrow and having the same rotating axis as the central body. A medium forming the ring is cold rarefied plasma with high electron density, so that electric conductivity of the medium tends to infinity, as well as the magnetic Reynolds number. The original mathematical model is reduced to a system of finite-difference equations whose asymptotic analytical solution is obtained. Emphasis is placed on the problems of stability of the ring's steady state rotation and quantization of the eigenvalues of nondimensional sector velocity of the ring with respect to the central body. The solutions corresponding to magneto-gravitational and to magneto-gyroscopic waves are considered It is demonstrated that some rings characterized by integral quantum numbers are stable and long-living, while the rings which are associated with half-integer quantum numbers (rings>) are unstable and short-living. As a result, an evolutionally rife rotating plasma ring turns out to be stratified into a large number of narrow elite rings separated by gaps whose position correspond to anti-rings. The regions of possible existence of elite rings in near-central body space are determined. The main result of eigenvalue spectrum's analysis is as follows. Quantum numbers determining elite eigenvalues of the sector velocity of a ring (normalized in a certain manner) coincide with the quantum

  18. The Search for Ringed Exoplanets

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-04-01

    Are planetary rings as common in our galaxy as they are in our solar system? A new study demonstrates how we might search for ringed exoplanets and then possibly finds one!Saturns Elsewhere?Artists illustration of the super ring system around exoplanet J1407b. This is the only exoplanet weve found with rings, but its not at all like Saturn. [Ron Miller]Our solar system is filled with moons and planetary rings, so it stands to reason that exoplanetary systems should exhibit the same features. But though weve been in the planet-hunting game for decades, weve only found one exoplanet thats surrounded by a ring system. Whats more, that system J1407b has enormous rings that are vastly different from the modest, Saturn-like rings that we might expect to be more commonplace.Have we not discovered ringed exoplanets just because theyre hard to identify? Or is it because theyre not out there? A team of scientists led by Masataka Aizawa (University of Tokyo) has set out to answer this question by conducting a systematic search for rings around long-period planet candidates.The transit light curve of KIC 10403228, shown with three models: the best-fitting planet-only model (blue) and the two best-fitting planet+ring models (green and red). [Aizawa et al. 2017]The Hunt BeginsWhy long-period planets? Rings are expected to be unstable as the planet gets closer to the central star. Whats more, the planet needs to be far enough away from the stars warmth for the icy rings to exist. The authors therefore select from the collection of candidate transiting planets 89 long-period candidates that might be able to host rings.Aizawa and collaborators then fit single-planet models (with no rings) to the light curves of these planets and search for anomalies curves that arent fit well by these standard models. Particularly suspicious characteristics include a long ingress/egress as the planet moves across the face of the star, and asymmetry of the transit shape.After applying a series of

  19. Red rubber bulb, cheap and effective vacuum drainage.

    PubMed

    Vatanasapt, V; Areemit, S; Jeeravipoolvarn, P; Kuyyakanond, T; Kuptarnond, C

    1989-04-01

    Red rubber bulbs have been used for vacuum drainage in head, neck, breast and several other operations by the authors since 1975 quite effectively without any major problems. The vacuum pressure of the red rubber bulbs was found to be higher than the expensive commercially available vacuum wound drainage device. The question of remaining old blood and infective microorganisms inside the reservoir for the reused ones were tested by the manual cleaning process and the standard sterile technique using steam under increased pressure (autoclave). The result is quite satisfactory. We encourage the use of this cheap and effective (made in Thailand) vacuum wound drainage in Thai hospitals and Thai medical schools.

  20. Study of Vacuum Energy Physics for Breakthrough Propulsion

    NASA Technical Reports Server (NTRS)

    Millis, Marc G. (Technical Monitor); Maclay, G. Jordan; Hammer, Jay; Clark, Rod; George, Michael; Kim, Yeong; Kir, Asit

    2004-01-01

    This report summarizes the accomplishments during a three year research project to investigate the use of surfaces, particularly in microelectromechanical systems (MEMS), to exploit quantum vacuum forces. During this project, we developed AFM instrumentation to repeatably measure Casimir forces in the nanoNewton range at 10 6 torr, designed an experiment to measure attractive and repulsive quantum vacuum forces, developed a QED based theory of Casimir forces that includes non-ideal material properties for rectangular cavities and for multilayer slabs, developed theoretical models for a variety of microdevices utilizing vacuum forces, applied vacuum physics to a gedanken spacecraft, and investigated a new material with a negative index of refraction.