Science.gov

Sample records for beam vacuum overpressure

  1. 33 CFR 154.2203 - Facility requirements for barge vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vapor overpressure and vacuum protection. 154.2203 Section 154.2203 Navigation and Navigable Waters... Installation § 154.2203 Facility requirements for barge vapor overpressure and vacuum protection. In this... valve or a vacuum relief valve apply only to facilities collecting vapors of flammable, combustible,...

  2. 33 CFR 154.2103 - Facility requirements for vessel vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vapor overpressure and vacuum protection. 154.2103 Section 154.2103 Navigation and Navigable Waters... § 154.2103 Facility requirements for vessel vapor overpressure and vacuum protection. In this section... valve or a vacuum relief valve apply only to facilities collecting vapors of flammable, combustible,...

  3. 46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011 Section 39.2011 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

  4. 46 CFR 39.2011 - Vapor overpressure and vacuum protection-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Vapor overpressure and vacuum protection-TB/ALL. 39.2011 Section 39.2011 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank...

  5. 33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... vapor overpressure and vacuum protection. 154.814 Section 154.814 Navigation and Navigable Waters COAST... vacuum protection. (a) A facility's vapor collection system must have the capacity for collecting cargo... vessel's cargo tanks between 80 percent of the highest setting of any of the vessel's vacuum...

  6. 33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... vapor overpressure and vacuum protection. 154.814 Section 154.814 Navigation and Navigable Waters COAST... vacuum protection. (a) A facility's vapor collection system must have the capacity for collecting cargo... vessel's cargo tanks between 80 percent of the highest setting of any of the vessel's vacuum...

  7. 33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... vapor overpressure and vacuum protection. 154.814 Section 154.814 Navigation and Navigable Waters COAST... vacuum protection. (a) A facility's vapor collection system must have the capacity for collecting cargo... vessel's cargo tanks between 80 percent of the highest setting of any of the vessel's vacuum...

  8. 33 CFR 154.814 - Facility requirements for vessel vapor overpressure and vacuum protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vapor overpressure and vacuum protection. 154.814 Section 154.814 Navigation and Navigable Waters COAST... vacuum protection. (a) A facility's vapor collection system must have the capacity for collecting cargo... vessel's cargo tanks between 80 percent of the highest setting of any of the vessel's vacuum...

  9. 46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... less than 0.5 psi below atmospheric pressure. (b) Each pressure-vacuum relief valve must: (1) Be tested... at 1.25 times the maximum transfer rate such that the pressure in the vapor space of each tank connected to the vapor collection system does not exceed: (i) The maximum design working pressure for...

  10. 46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... less than 0.5 psi below atmospheric pressure. (b) Each pressure-vacuum relief valve must: (1) Be tested... at 1.25 times the maximum transfer rate such that the pressure in the vapor space of each tank connected to the vapor collection system does not exceed: (i) The maximum design working pressure for...

  11. 46 CFR 39.20-11 - Vapor overpressure and vacuum protection-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... less than 0.5 psi below atmospheric pressure. (b) Each pressure-vacuum relief valve must: (1) Be tested... at 1.25 times the maximum transfer rate such that the pressure in the vapor space of each tank connected to the vapor collection system does not exceed: (i) The maximum design working pressure for...

  12. Non-Vacuum Electron Beam Welding

    SciTech Connect

    Hershcovitch, Ady

    2007-01-31

    Original objectives of CRADA number BNL-01-03 between BNL and Acceleron, Inc., were to further develop the Plasma Window concept (a BNL invention covered by US Patent number 5,578,831), mate the Plasma Window to an existing electron beam welder to perform in-air electron beam welding, and mount the novel nonvacuum electron beam welder on a robot arm. Except for the last objective, all other goals were met or exceeded. Plasma Window design and operation was enhanced during the project, and it was successfully mated to a conventional4 kW electron beam welder. Unprecedented high quality non-vacuum electron beam . welding was demonstrated. Additionally, a new invention the Plasma Shield (US Patent number 7,075,030) that chemically and thermally shields a target object was set forth. Great interest in the new technology was shown by a number of industries and three arcs were sold for experimental use. However, the welding industry requested demonstration of high speed welding, which requires 100 kW electron beam welders. The cost of such a welder involved the need for additional funding. Therefore, some of the effort was directed towards Plasma Shield development. Although relatively a small portion of the R&D effort was spent on the Plasma Shield, some very encouraging results were obtained. Inair Plasma Shield was demonstrated. With only a partial shield, enhanced vacuum separation and cleaner welds were realized. And, electron beam propagation in atmosphere improved by a factor of about 3. Benefits to industry are the introduction of two new technologies. BNL benefited from licensing fee cash, from partial payment for employee salary, and from a new patent In addition to financial benefits, a new technology for physics studies was developed. Recommendations for future work are to develop an under-water plasma shield, perform welding with high-power electron beam:s, carry out other plasma shielded electron beam and laser processes. Potential benefits from further R

  13. Vacuum chamber for containing particle beams

    DOEpatents

    Harvey, A.

    1985-11-26

    A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer such as nickel can be coated on the inside of the pipe.

  14. Vacuum chamber for containing particle beams

    DOEpatents

    Harvey, Alexander

    1987-01-01

    A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer, such as nickel can be coated on the inside of the pipe.

  15. Vacuum straw tracker test beam run

    SciTech Connect

    Wah, Yau; /Chicago U.

    2005-08-01

    This memorandum of understanding requests beam time at Fermilab during the 2005 Meson Test Beam run to measure the detection inefficiency of vacuum straw tubes. One of the future kaon experiments at J-PARC has the goal to measure the branching ratio of the neutral kaon ''Golden Mode'' K{sub L} {yields} {pi}{sup 0} with a few hundred event sensitivity. This future J-PARC experiment is a follow up of a current KEK experiment, E391a which has been taking data since February 2004. E391a is a collaboration of five countries (Japan, United States, Russia, Korea, and Taiwan) with ten institutions (KEK, Saga U, Yamagata U, Osaka U, U of Chicago, Pusan U, JINR, NDA, Kyoto U, National Taiwan U, and RCNP). The branching ratio of K{sub L} {yields} {pi}{sup 0} {nu} {nu} is small, about 3 x 10{sup -11}. To first order, all kaon decays with final states with charged particles need to be vetoed, and those include K{sub e3}, K{sub {mu}3}, and K{sub {+-}0} (about 80% of all neutral kaon decay). The standard and typical veto power comes from sheet scintillator and may not be adequate. Vacuum straw tubes provides additional, independent and orthogonal veto power, but the detection inefficiency has not been known or measured in a detail way. The inefficiency of the straw has three sources, the electronics, the straw wall/wire, and the gas. We like to perform beam test to measure all three sources. There is much experience in straw detector technology, and some in vacuum straw technology (CKM R&D effort). The possible use of straws in the future K{sub L} {yields} {pi}{sup 0} {nu} {nu} experiment will allow absolute photon/electron energy calibration (via K{sub {+-}0} decays), possible measurement of photon inefficiencies (via K{sub 000} with {pi}{sup 0} Dalitz), and as mentioned, charged particle veto. The results of this proposed beam test will provide new knowledge on the absorption cross section and will direct us on design issues for future neutral kaon decay experiments. Regarding

  16. Vacuum ring exit chamber temperatures due to wiggler beam heating

    SciTech Connect

    Sharma, S.; Ulc, S.

    1984-01-01

    A study was made to determine the effects of a shift in the electron orbital plane and resulting displacement of the wiggler photon beam striking the inner surface of the existing vacuum chamber outer wall. The wiggler beam/vacuum chamber geometry is shown. 7 figures.

  17. Beam tube vacuum in future superconducting proton colliders

    SciTech Connect

    Turner, W.

    1994-10-01

    The beam tube vacuum requirements in future superconducting proton colliders that have been proposed or discussed in the literature -- SSC, LHC, and ELN -- are reviewed. The main beam tube vacuum problem encountered in these machines is how to deal with the magnitude of gas desorption and power deposition by synchrotron radiation while satisfying resistivity, impedance, and space constraints in the cryogenic environment of superconducting magnets. A beam tube vacuum model is developed that treats photodesorption of tightly bound H, C, and 0, photodesorption of physisorbed molecules, and the isotherm vapor pressure of H{sub 2}. Experimental data on cold tube photodesorption experiments are reviewed and applied to model calculations of beam tube vacuum performance for simple cold beam tube and liner configurations. Particular emphasis is placed on the modeling and interpretation of beam tube photodesorpiion experiments at electron synchrotron light sources. The paper also includes discussion of the constraints imposed by beam image current heating, the growth rate of the resistive wall instability, and single-bunch instability impedance limits.

  18. Improved double beam, vacuum far infrared spectrophotometer.

    PubMed

    Iwahashi, I; Matsumoto, K; Matsudaira, S; Minami, S; Yoshinaga, H

    1969-03-01

    A double beam far ir spectrophotometer was improved in order to give more convenience and higher performance. The instrument is evacuable and the sample chamber alone can also be purged with dry air to remove water vapor. Three photometric systems, i.e., conventional double beam, double beam double chopping, and single beam systems can be selected for versatile measurements. The use of an efficient transmission filter system, not involving deliquescent crystals, results in many operational advantages. Accordingly, high resolution can be obtained through the entire spectral region from 400 cm(-1) to 30 cm(-1) Moreover, 30-min scan over the entire spectral region is achieved by completely automatic operation with a refined control system.

  19. Nonlinear Self-Similar Beams of Electromagnetic Waves in Vacuum

    NASA Astrophysics Data System (ADS)

    Vlasov, S. N.

    2015-12-01

    We study nonlinear beams of electromagnetic waves in vacuum. Within the lowest approximation, their structure is determined by the cubic self-focusing nonlinearity, which manifests itself with the maximum intensity in the presence of counterpropagating waves. It is shown that the fields in the beams have no singularities if their power is less than the critical power of the self-focusing. The dependences of the eigenfrequencies of the modes of the quasioptical resonator on the beam power are found. The structure of the fields of these modes corresponds to self-similar wave beams.

  20. Ultrahigh vacuum focused ion beam micromill and articles therefrom

    DOEpatents

    Lamartine, B.C.; Stutz, R.A.

    1998-02-24

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are disclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters. 6 figs.

  1. Ultrahigh vacuum focused ion beam micromill and articles therefrom

    DOEpatents

    Lamartine, Bruce C.; Stutz, Roger A.

    1998-01-01

    An ultrahigh vacuum focused ion beam micromilling apparatus and process are isclosed. Additionally, a durable data storage medium using the micromilling process is disclosed, the durable data storage medium capable of storing, e.g., digital or alphanumeric characters as well as graphical shapes or characters.

  2. Pulsed particle beam vacuum-to-air interface

    DOEpatents

    Cruz, G.E.; Edwards, W.F.

    1987-06-18

    A vacuum-to-air interface is provided for a high-powered, pulsed particle beam accelerator. The interface comprises a pneumatic high speed gate valve, from which extends a vacuum-tight duct, that terminates in an aperture. Means are provided for periodically advancing a foil strip across the aperture at the repetition rate of the particle pulses. A pneumatically operated hollow sealing band urges foil strip, when stationary, against and into the aperture. Gas pressure means periodically lift off and separate foil strip from aperture, so that it may be readily advanced. 5 figs.

  3. Requirements and guidelines for NSLS experimental beam line vacuum systems: Revision A

    SciTech Connect

    Foerster, C.; Halama, H.; Thomlinson, W.

    1986-10-01

    Requirements are provided for NSLS beam line front ends and vacuum interlocks. Guidelines are provided for UHV beam line vacuum systems, including materials, vacuum hardware (pumps, valves, and flanges), acoustic delay lines and beam line fast valves, instrumentation, fabrication and testing, and the NSLS cleaning facility. Also discussed are the design review for experimenters' equipment that would be connected to the NSLS and acceptance tests for any beam line to be connected with the ring vacuum. Also appended are a description of the acoustic delay line as well as the NSLS vacuum standards and NSLS procedures. (LEW)

  4. Pulsed particle beam vacuum-to-air interface

    DOEpatents

    Cruz, Gilbert E.; Edwards, William F.

    1988-01-01

    A vacuum-to-air interface (10) is provided for a high-powered, pulsed particle beam accelerator. The interface comprises a pneumatic high speed gate valve (18), from which extends a vacuum-tight duct (26), that termintes in an aperture (28). Means (32, 34, 36, 38, 40, 42, 44, 46, 48) are provided for periodically advancing a foil strip (30) across the aperture (28) at the repetition rate of the particle pulses. A pneumatically operated hollow sealing band (62) urges foil strip (30), when stationary, against and into the aperture (28). Gas pressure means (68, 70) periodically lift off and separate foil strip (30) from aperture (28), so that it may be readily advanced.

  5. Molecular beam deposition of nanoscale ionic liquids in ultrahigh vacuum.

    PubMed

    Maruyama, Shingo; Takeyama, Yoko; Taniguchi, Hiroki; Fukumoto, Hiroki; Itoh, Mitsuru; Kumigashira, Hiroshi; Oshima, Masaharu; Yamamoto, Takakazu; Matsumoto, Yuji

    2010-10-26

    We propose a new approach to nanoscience and technology for ionic liquids (ILs): molecular beam deposition of IL in ultrahigh vacuum by using a continuous wave infrared (CW-IR) laser deposition technique. This approach has made it possible to prepare a variety of "nano-IL" with the given composition on the substrate: a nanodroplet, on one hand, the volume of which goes down to 1 aL and, on the other hand, an ultrathin film with a thickness to several 100 nm or less. The result of fractional distillation of a binary mixture of ILs, investigated by nuclear magnetic resonance as well as electrospray ionization time-of-flight mass spectrometry, indicates that this deposition process is based on the thermal evaporation of ILs, and thus this process also can be used as a new purification method of ILs in vacuum. Furthermore, the fabrication of binary mixture droplets of two ILs on the substrate by alternating deposition of two ILs was demonstrated; the homogeneity of the composition was confirmed even for one single droplet by high-spatial-resolution Raman spectroscopy.

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

    SciTech Connect

    FOERSTER,C.

    1999-05-01

    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 after 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 of front

  7. Novel multi-beam X-ray source for vacuum electronics enabled medical imaging applications

    NASA Astrophysics Data System (ADS)

    Neculaes, V. Bogdan

    2013-10-01

    For almost 100 of years, commercial medical X-ray applications have relied heavily on X-ray tube architectures based on the vacuum electronics design developed by William Coolidge at the beginning of the twentieth century. Typically, the Coolidge design employs one hot tungsten filament as the electron source; the output of the tube is one X-ray beam. This X-ray source architecture is the state of the art in today's commercial medical imaging applications, such as Computed Tomography. Recently, GE Global Research has demonstrated the most dramatic extension of the Coolidge vacuum tube design for Computed Tomography (CT) in almost a century: a multi-beam X-ray source containing thirty two cathodes emitting up to 1000 mA, in a cathode grounded - anode at potential architecture (anode up to 140 kV). This talk will present the challenges of the X-ray multi-beam vacuum source design - space charge electron gun design, beam focusing to compression ratios needed in CT medical imaging applications (image resolution is critically dependent on how well the electron beam is focused in vacuum X-ray tubes), electron emitter choice to fit the aggressive beam current requirements, novel electronics for beam control and focusing, high voltage and vacuum solutions, as well as vacuum chamber design to sustain the considerable G forces typically encountered on a CT gantry (an X-ray vacuum tube typically rotates on the CT gantry at less than 0.5 s per revolution). Consideration will be given to various electron emitter technologies available for this application - tungsten emitters, dispenser cathodes and carbon nano tubes (CNT) - and their tradeoffs. The medical benefits potentially enabled by this unique vacuum multi-beam X-ray source are: X-ray dose reduction, reduction of image artifacts and improved image resolution. This work was funded in part by NIH grant R01EB006837.

  8. Mechanism analysis of radiation generated by the beam-plasma interaction in a vacuum diode

    NASA Astrophysics Data System (ADS)

    Ji, Zengchao; Chen, Shixiu; Gao, Shen

    2017-01-01

    When we were studying the vacuum switch, we found that the vacuum diode can radiate a broadband microwave. The vacuum diode is comprised of a cathode with a trigger device and planar anode, there is not a metallic bellows waveguide structure in this device, so the radiation mechanism of the vacuum diode is different from the plasma filled microwave device. It is hard to completely imitate the theory of the plasma filled microwave device. This paper analyzes the breakdown process of the vacuum diode, establishes the mathematical model of the radiating microwave from the vacuum diode. Based on the analysis of the dispersion relation in the form of a refractive index, the electromagnetic waves generated in the vacuum diode will resonate. The included angle between the direction of the electromagnetic radiation and the initial motion direction of electron beam is 45 degrees. The paper isolates the electrostatic effect from the beam-plasma interaction when the electromagnetic radiation occurs. According to above analyses, the dispersion relations of radiation are obtained by solving the wave equation. The dispersion curves are also obtained based on the theoretical dispersion relations. The theoretical dispersion curves are consistent with the actual measurement time-frequency maps of the radiation. Theoretical deduction and experiments indicate that the reason for microwave radiating from the vacuum diode can be well explained by the interaction of the electron beam and magnetized plasma. Supported by National Nature Science Foundation of China (No. 11075123), the Young Scientists Fund of Nature Science Foundation of China (No. 51207171).

  9. Mechanism analysis of radiation generated by the beam-plasma interaction in a vacuum diode

    NASA Astrophysics Data System (ADS)

    Zengchao, Ji; Shixiu, Chen; Shen, Gao

    2017-01-01

    When we were studying the vacuum switch, we found that the vacuum diode can radiate a broadband microwave. The vacuum diode is comprised of a cathode with a trigger device and planar anode, there is not a metallic bellows waveguide structure in this device, so the radiation mechanism of the vacuum diode is different from the plasma filled microwave device. It is hard to completely imitate the theory of the plasma filled microwave device. This paper analyzes the breakdown process of the vacuum diode, establishes the mathematical model of the radiating microwave from the vacuum diode. Based on the analysis of the dispersion relation in the form of a refractive index, the electromagnetic waves generated in the vacuum diode will resonate. The included angle between the direction of the electromagnetic radiation and the initial motion direction of electron beam is 45 degrees. The paper isolates the electrostatic effect from the beam-plasma interaction when the electromagnetic radiation occurs. According to above analyses, the dispersion relations of radiation are obtained by solving the wave equation. The dispersion curves are also obtained based on the theoretical dispersion relations. The theoretical dispersion curves are consistent with the actual measurement time-frequency maps of the radiation. Theoretical deduction and experiments indicate that the reason for microwave radiating from the vacuum diode can be well explained by the interaction of the electron beam and magnetized plasma. Supported by National Nature Science Foundation of China (No. 11075123), the Young Scientists Fund of Nature Science Foundation of China (No. 51207171).

  10. Beam induced vacuum measurement error in BEPC II

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Xiao, Qiong; Peng, XiaoHua; Wang, HaiJing

    2011-12-01

    When the beam in BEPCII storage ring aborts suddenly, the measured pressure of cold cathode gauges and ion pumps will drop suddenly and decrease to the base pressure gradually. This shows that there is a beam induced positive error in the pressure measurement during beam operation. The error is the difference between measured and real pressures. Right after the beam aborts, the error will disappear immediately and the measured pressure will then be equal to real pressure. For one gauge, we can fit a non-linear pressure-time curve with its measured pressure data 20 seconds after a sudden beam abortion. From this negative exponential decay pumping-down curve, real pressure at the time when the beam starts aborting is extrapolated. With the data of several sudden beam abortions we have got the errors of that gauge in different beam currents and found that the error is directly proportional to the beam current, as expected. And a linear data-fitting gives the proportion coefficient of the equation, which we derived to evaluate the real pressure all the time when the beam with varied currents is on.

  11. In vacuum diamond sensor scanner for beam halo measurements in the beam line at the KEK Accelerator Test Facility

    NASA Astrophysics Data System (ADS)

    Liu, S.; Bogard, F.; Cornebise, P.; Faus-Golfe, A.; Fuster-Martínez, N.; Griesmayer, E.; Guler, H.; Kubytskyi, V.; Sylvia, C.; Tauchi, T.; Terunuma, N.; Bambade, P.

    2016-10-01

    The investigation of beam halo transverse distributions is important for the understanding of beam losses and the control of backgrounds in Future Linear Colliders (FLC). A novel in vacuum diamond sensor (DSv) scanner with four strips has been designed and developed for the investigation of the beam halo transverse distributions and also for the diagnostics of Compton recoil electrons after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for the ILC and CLIC linear collider projects. Using the DSv, a dynamic range of ∼106 has been successfully demonstrated and confirmed for the first time in simultaneous beam core (∼109 electrons) and beam halo (∼103 electrons) measurements at ATF2. This report presents the characterization, performance studies and tests of diamond sensors using an α source, as well as using the electron beams at PHIL, a low energy < 5 MeV photo-injector at LAL, and at ATF2. First beam halo measurement results using the DSv at ATF2 with different beam intensities and vacuum levels are also presented. Such measurements not only allow one to evaluate the different sources of beam halo generation but also to define the requirements for a suitable collimation system to be installed at ATF2, as well as to optimize its performance during future operation.

  12. Comparing 193 nm photoresist roughening in an inductively coupled plasma system and vacuum beam system

    NASA Astrophysics Data System (ADS)

    Titus, M. J.; Nest, D. G.; Chung, T.-Y.; Graves, D. B.

    2009-12-01

    We present a comparison of blanket 193 nm photoresist (PR) roughening and chemical modifications of samples processed in a well-characterized argon (Ar) inductively coupled plasma (ICP) system and an ultra-high vacuum beam system. In the ICP system, PR samples are irradiated with Ar vacuum ultraviolet (VUV) and Ar ions, while in the vacuum beam system, samples are irradiated with either a Xe-line VUV source or Ar-lamp VUV source with Ar ions. Sample temperature, photon flux, ion flux and ion energy are controlled and measured. The resulting chemical modifications to bulk 193 nm PR and surface roughness are analysed with Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy. We demonstrate that under VUV-only conditions in the vacuum beam and ICP (with no substrate bias applied) systems 193 nm PR does not roughen. However, roughness increases with simultaneous high energy (>70 eV) ion bombardment and VUV irradiation and is a function of VUV fluence, substrate temperature and photon-to-ion flux ratio. PR processed in the ICP system experiences increased etching, probably due to release of H- and O-containing gaseous products and subsequent chemical etching, in contrast to samples in the vacuum beam system where etch-products are rapidly pumped away. The surface roughness structure and behaviour, however, remain similar and this is attributed to the synergy between VUV-photon and positive ions.

  13. Performance of the beam chamber vacuum system of K = 500 cyclotron at Variable Energy Cyclotron Centre Kolkata.

    PubMed

    Pal, Gautam; DuttaGupta, Anjan; Chakrabarti, Alok

    2014-07-01

    The beam chamber of Variable Energy Cyclotron Centre, Kolkata's K = 500 superconducting cyclotron is pumped by liquid helium cooled cryopanel with liquid nitrogen cooled radiation shield. Performance of the vacuum system was evaluated by cooling the cryopanel assembly with liquid nitrogen and liquid helium. Direct measurement of beam chamber pressure is quite difficult because of space restrictions and the presence of high magnetic field. Pressure gauges were placed away from the beam chamber. The beam chamber pressure was evaluated using a Monte Carlo simulation software for vacuum system and compared with measurements. The details of the vacuum system, measurements, and estimation of pressure of the beam chamber are described in this paper.

  14. A vacuum spark ion source: High charge state metal ion beams

    NASA Astrophysics Data System (ADS)

    Yushkov, G. Yu.; Nikolaev, A. G.; Oks, E. M.; Frolova, V. P.

    2016-02-01

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  15. A vacuum spark ion source: High charge state metal ion beams

    SciTech Connect

    Yushkov, G. Yu. Nikolaev, A. G.; Frolova, V. P.; Oks, E. M.

    2016-02-15

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  16. Development of High Power Electron Beam Measuring and Analyzing System for Microwave Vacuum Electron Devices

    NASA Astrophysics Data System (ADS)

    Ruan, C. J.; Wu, X. L.; Li, Q. S.; Li, C. S.

    The measurement and analysis of high power electron beam during its formation and transmission are the basic scientific problems and key techniques for the development of high performance microwave vacuum electron devices, which are widely used in the fields of military weapon, microwave system and scientific instruments. In this paper, the dynamic parameters measurement and analysis system being built in Institute of Electronics, Chinese Academy of Sciences (IECAS) recently are introduced. The instrument are designed to determine the cross-section, the current density, and the energy resolution of the high power electron beam during its formation and transmission process, which are available both for the electron gun and the electron optics system respectively. Then the three dimension trajectory images of the electron beam can be rebuilt and display with computer controlled data acquisition and processing system easily. Thus, much more complicated structures are considered and solved completely to achieve its detection and analysis, such as big chamber with 10-6 Pa high vacuum system, the controlled detector movement system in axis direction with distance of 600 mm inside the vacuum chamber, the electron beam energy analysis system with high resolution of 0.5%, and the electron beam cross-section and density detector using the YAG: Ce crystal and CCD imaging system et al. At present, the key parts of the instrument have been finished, the cross-section experiment of the electron beam have been performed successfully. Hereafter, the instrument will be used to measure and analyze the electron beam with the electron gun and electron optics system for the single beam and multiple beam klystron, gyrotron, sheet beam device, and traveling wave tube etc. thoroughly.

  17. An Enhanced Vacuum Arc Ion Source for High Current, High Charge State Uranium Beam Production

    NASA Astrophysics Data System (ADS)

    Johnson, B. M.; Hershcovitch, A.; Brown, I. G.; Leemans, W.; Liu, F.

    1996-05-01

    We plan to carry out an experimental program at LBNL to develop a novel kind of vacuum arc ion source in which the metal ions are further stripped by interaction with an energetic, dense electron beam. Preliminary results obtained by Batalin et al.(V. A. Batalin, Y. N. Volkov, T. V. Kulevoy, and S. V. Petrenko, ITEP, Moscow, Reprints 18-93 (1993), 33-94 (1994); Proc. EPAC 1994, p. 1453.) using this approach have been most promising; the vacuum arc ion source(I.G. Brown, ``Vacuum Arc Ion Sources'', Rev. Sci. Instrum. 65, 3061 (1994).) uranium ion beam output of mostly U^3+ ions was increased significantly, although the yield of high charge state ions was only a small fraction of the original source current. In our experiments the electron beam will propagate antiparallel to the ion beam so as to provide a radially inward Lorentz force to confine and focus the stripped uranium beam, thus maximizing the electron-ion interactions and increasing the ion beam current density. We expect improved performance over the encouraging earlier^1 results. The motivation for this work(Ady Hershcovitch and Brant Johnson, RHIC/DET Note 17 and AGS/ ADD/Tech. Note No. 416) is the desire to eventually inject fully stripped uranium into the Relativistic Heavy Ion Collider (RHIC).

  18. The CpFM, an in-vacuum Cherenkov beam monitor for UA9 at SPS

    NASA Astrophysics Data System (ADS)

    Puill, V.; Addesa, F.; Burmistrov, L.; Breton, D.; Chaumat, V.; Cavoto, G.; Conforti Di Lorenzo, S.; Dubos, S.; Gavrikov, Yu. A.; Iacoangeli, F.; Jeglot, J.; Maalmi, J.; Natochii, A.; Rossi, R.; Montesano, S.; Scandale, W.; Stocchi, A.; Vagnucci, J.-F.

    2017-04-01

    The use of bent crystals for beam manipulation in particle accelerators is a well-assessed concept rapidly evolving into practical application. The experiments of the UA9 collaboration at the CERN-SPS have played a key role for a quantitative understanding of channeling and volume reflection mechanisms. Investigation of the channeling process close to a circulating beam ideally requires in vacuum detectors resolving the single particle, which should be located inside the vacuum pipe itself. Cherenkov radiators are potential candidates for such functionality due the reduced electro-magnetic interaction of the radiator material with the circulating charges and their compatibility with vacuum requirements in the beam pipe. For this purpose, we developed a device called Cherenkov detector for proton Flux Measurement (CpFM) that aims at counting the number of deflected protons of the beam halo surrounding the circulating beam with an accuracy of 15%. After a detailed description of the detection chain and its simulation, we present results of beam tests of different configurations, the calibration of the final device and the results of its first operation in the SPS.

  19. RF impedance studies of a beam chamber and longitudinally slot-coupled vacuum pumping antechamber

    SciTech Connect

    Kustom, R.L.; Nicholls, G.L.; Kramer, S.L.; Khoe, T.K.; Cook, J.M.

    1987-01-01

    The storage ring vacuum chamber of the proposed 7-GeV synchrotron light source at Argonne National Laboratory is planned to have a semi-elliptical beam chamber, with a longitudinal slot coupled to an antechamber containing NEG pumping strips. Concern over the RF impedance of this complex chamber has stimulated the need to understand the limitations it will have on the beam intensity, the RF acceleration system and on the beam lifetime. Calculations using numerical EM field programs have estimated the waveguide modes of this chamber and the impedance and loss parameter for the expected 1 to 2 cm beam bunch length. The loss parameter is shown to differ little from an elliptical beam chamber without the slot and antechamber. An experimental program has begun to verify the estimates of the impedance for these complex vacuum chamber components using laboratory methods. Preliminary results are presented for the measured loss parameter for a short length of beam vacuum chamber and for other components. These results are compared with their calculated values.

  20. Inertially excited beam vibrations damped by Vacuum Packed Particles

    NASA Astrophysics Data System (ADS)

    Szmidt, T.; Zalewski, R.

    2014-10-01

    The dynamics of an inertially excited steel cantilever beam encapsulated in a hermetic sleeve filled with polypropylene grains is investigated experimentally and theoretically. An electric motor rotating an unbalanced mass is attached at the end of the beam to generate forced vibrations of the system. Changing the underpressure in the sleeve results in changes of the stiffness and dissipative properties of the composite structure, which allow one to control the resonant characteristics of the system. Is is shown that the amplitude of vibrations can be reduced in this way. This innovative semi-active method of vibration damping is based on the jamming mechanism of the granules, and proved to be efficient in the reduction of the free vibrations of the beam, which was studied in the authors’ latest paper. In the present work, it is confirmed that the classical Bernoulli-Euler beam model with Kelvin-Voigt damping provides a satisfactory explanation of the observed relation between the vibrations amplitude and underpressure.

  1. PEP-II vacuum system - joining SS flanges to copper beam chambers

    SciTech Connect

    Fetzko, S.; Hoyt, E.; Cummings, U.

    1994-06-01

    Various methods of joining stainless steel flanges to the copper PEP-II high-energy ring vacuum chambers was investigated with regard to metallurgical soundness, reliability, complexity, and cost. The most promising method appears to be direct electron-beam welding.

  2. Enhanced direct laser vacuum acceleration of a charged particle in crossing plane-wave laser beams

    SciTech Connect

    Lin, H; Liu, C P; Wang, C; Shen, B F

    2015-09-30

    Strict theory shows that in the field of two laser beams crossing in vacuum with a phase delay π/2, a unique dynamics of the electron is observed. Unlike a single-beam case in which the velocity component along the laser magnetic field is always zero, the electron motion in the case of crossing beams is completely three-dimensional and hence a larger maximum value of the relativistic factor Γ, i.e. acceleration of an electron to larger energies, can be achieved. (laser acceleration of electrons)

  3. Electron beam gun with kinematic coupling for high power RF vacuum devices

    DOEpatents

    Borchard, Philipp

    2016-11-22

    An electron beam gun for a high power RF vacuum device has components joined by a fixed kinematic coupling to provide both precise alignment and high voltage electrical insulation of the components. The kinematic coupling has high strength ceramic elements directly bonded to one or more non-ductile rigid metal components using a high temperature active metal brazing alloy. The ceramic elements have a convex surface that mates with concave grooves in another one of the components. The kinematic coupling, for example, may join a cathode assembly and/or a beam shaping focus electrode to a gun stem, which is preferably composed of ceramic. The electron beam gun may be part of a high power RF vacuum device such as, for example, a gyrotron, klystron, or magnetron.

  4. IMPEDANCE OF ELECTRON BEAM VACUUM CHAMBERS FOR THE NSLS-II STORAGE RING.

    SciTech Connect

    BLEDNYKH,A.; KRINSKY, S.

    2007-06-25

    In this paper we discuss computation of the coupling impedance of the vacuum chambers for the NSLS-II storage ring using the electromagnetic simulator GdfidL [1]. The impedance of the vacuum chambers depends on the geometric dimensions of the cross-section and height of the slot in the chamber wall. Of particular concern is the complex geometry of the infrared extraction chambers to be installed in special large-gap dipole magnets. In this case, wakefields are generated due to tapered transitions and large vertical-aperture ports with mirrors near the electron beam.

  5. Devices useful for vacuum ultraviolet beam characterization including a movable stage with a transmission grating and image detector

    DOEpatents

    Gessner, Oliver; Kornilov, Oleg A; Wilcox, Russell B

    2013-10-29

    The invention provides for a device comprising an apparatus comprising (a) a transmission grating capable of diffracting a photon beam into a diffracted photon output, and (b) an image detector capable of detecting the diffracted photon output. The device is useful for measuring the spatial profile and diffraction pattern of a photon beam, such as a vacuum ultraviolet (VUV) beam.

  6. Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum

    SciTech Connect

    Zhu, X.P.; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi; Lei, M.K.

    2005-08-29

    Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2x10{sup -2} Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms/molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.

  7. Scalloped Hibachi and Vacuum-Pressure Foil for Electra: Electron Beam Pumped KrF Laser

    DTIC Science & Technology

    2007-06-01

    SCALLOPED HIBACHI AND VACUUM-PRESSURE FOIL FOR ELECTRA: ELECTRON BEAM PUMPED KrF LASER∗ R. Jaynes+, T. Albert++, F. Hegeler ++ and J. D. Sethian... Hegeler , S. B. Swanekamp, D. Weidenheimer, D. Welch, D. V. Rose, S. Searles, “Electron beam pumped KrF lasers for fusion energy,” Physics of...chambers ,” Nuclear Fusion, vol.43, pp. 1693-1709, December 2003. [8] F. Hegeler , M. C. Myers, M. F. Wolford, J. D. Sethian, R. Jaynes, P. Burns, M

  8. A low-profile molecular beam source isolation valve for ultrahigh vacuum applications

    NASA Astrophysics Data System (ADS)

    Chaban, E. E.; Reutt-Robey, J. E.

    1993-08-01

    We describe the design of a novel low-profile valve to isolate a molecular beam source from an ultrahigh vacuum system. The valve thickness is simply the thickness of a standard double-sided Conflat flange, on which the valve gate and actuation mechanism are assembled in a fully recessed configuration. The valve gate can accommodate a skimmer and/or several source collimating apertures. The manual actuator is mounted radial to the Conflat flange.

  9. Electromagnetic levitation facility incorporating electron beam. [for vacuum heating and melting

    NASA Technical Reports Server (NTRS)

    Wouch, G.; Okress, E. C.; Frost, R. T.; Rutecki, D. J.

    1975-01-01

    An electromagnetic levitation apparatus incorporating an electron beam for auxiliary heating and melting has been developed for experiments on containerless vacuum purification and undercooled solidification of high melting materials. Stable levitation of 10-g specimens of molten tungsten has been achieved and a variety of containerless solidification experiments is being performed, including pure polycrystalline castings and single tungsten crystals grown from the undercooled levitated melts.

  10. Design of large vacuum chamber for VEC superconducting cyclotron beam line switching magnet

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sumantra; Nandi, Chinmoy; Gayen, Subhasis; Roy, Suvadeep; Mishra, Santosh Kumar; Ramrao Bajirao, Sanjay; Pal, Gautam; Mallik, C.

    2012-11-01

    VEC K500 superconducting cyclotron will be used to accelerate heavy ion. The accelerated beam will be transported to different beam halls by using large switching magnets. The vacuum chamber for the switching magnet is around 1000 mm long. It has a height of 85 mm and width varying from 100 mm to 360 mm. The material for the chamber has been chosen as SS304.The material for the vacuum chamber for the switching magnet has been chosen as SS304. Design of the vessel was done as per ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. It was observed that primary stress values exceed the allowable limit. Since, the magnet was already designed with a fixed pole gap; increase of the vacuum chamber plate thickness restricts the space for beam transport. Design was optimized using stress analysis software ANSYS. Analysis was started using plate thickness of 4 mm. The stress was found higher than the allowable level. The analysis was repeated by increasing plate thickness to 6 mm, resulting in the reduction of stress level below the allowable level. In order to reduce the stress concentration due to sharp bend, chamfering was done at the corner, where the stress level was higher. The thickness of the plate at the corner was increased from 6 mm to 10 mm. These measures resulted in reduction of localized stress.

  11. Overpressure by burial

    NASA Astrophysics Data System (ADS)

    Podladchikov, Yury; Dabrowski, Marcin

    2017-04-01

    Preservation of peak metamorphic assemblages cannot be explain by sluggish kinetics only due to high temperatures. Moreover, frequently reported near isothermal decompression from peak conditions testify continuing capacity of lower pressure metamorphic reactions to overcome kinetic barriers. Often these observations come from the same rock sample, or even or from a single host crystal. Natural conclusion on preservation of peak pressures in a 'pressure vessel' in order to preserve the peak mineral assemblages was firmly made already in the first years after convincing identifying of ultra-high pressure minerals in continental rocks. The 'pressure vessels' model is thus the current view on mechanical state during retrogression assuming up to several GPa excess pressure in inclusion maintained by host mineral all the way through retrogression. Same arguments apply to preservation of outcrop scale eclogite boudins in lower pressure amphibolite gneisses. If strength of rocks and minerals is sufficient to keep the pressure difference during retrogression, the same applies to the prograde stage of the metamorphic history of the rock. We investigate and quantify the overpressure development during burial of continental rocks. We show that eclogite lenses are expected to develop over mafic lithology embedded in average crustal rock at lower crustal condition, thus eliminating the need for 'deep continental subduction' as the only mechanism to form it.

  12. The interdisciplinary use of ;overpressure;

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Anderson, M. W.; Rotevatn, A.; Sanderson, D. J.; Tavarnelli, E.

    2017-07-01

    Overpressure is a polysemic word that has a variety of meanings within and across different disciplines. This is likely to be a particular problem in analysis of geothermal resources, where reservoir engineers, volcanologists and structural geologists may each confidently use overpressure but mean different things. We suggest that, to avoid confusion, the term should be carefully and accurately defined whenever used, and ideally only used to mean fluid pressure in excess of hydrostatic pressure.

  13. Toxicology of blast overpressure.

    PubMed

    Elsayed, N M

    1997-07-25

    Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that are occurring worldwide with greater frequency. Exposure to incident BOP waves can cause auditory and non-auditory damage. The primary targets for BOP damage are the hollow organs, ear, lung and gastrointestinal tract. In addition, solid organs such as heart, spleen and brain can also be injured upon exposure. However, the lung is more sensitive to damage and its injury can lead to death. The pathophysiological responses, and mortality have been extensively studied, but little attention, was given to the biochemical manifestations, and molecular mechanism(s) of injury. The injury from BOP has been, generally, attributed to its external physical impact on the body causing internal mechanical damage. However, a new hypothesis has been proposed based on experiments conducted in the Department of Respiratory Research, Walter Reed Army Institute of Research, and later in the Department of Occupational Health, University of Pittsburgh. This hypothesis suggests that subtle biochemical changes namely, free radical-mediated oxidative stress occur and contribute to BOP-induced injury. Understanding the etiology of these changes may shed new light on the molecular mechanism(s) of injury, and can potentially offer new strategies for treatment. In this symposium. BOP research involving auditory, non-auditory, physiological, pathological, behavioral, and biochemical manifestations as well as predictive modeling and current treatment modalities of BOP-induced injury are discussed.

  14. Mechanical performance of electron-beam-irradiated UHMWPE in vacuum and in air.

    PubMed

    Visco, A M; Torrisi, L; Campo, N; Emanuele, U; Trifirò, A; Trimarchi, M

    2009-04-01

    Ultrahigh molecular weight polyethylene (UHMWPE) was modified by a 5-MeV energy electron beam at different temperatures before, during, and after irradiation, both in air and in high vacuum. Wear resistance, hardness, and tensile strength of irradiated polyethylene were compared with those of untreated one. Physical analyses (like infrared spectroscopy and calorimetric analysis) were carried out to investigate about the changes in the material induced by irradiation. Experimental results suggested that structural changes (double bonds, crosslinks, and oxidized species formation) occur in the polymer depending on the environmental conditions of the irradiation. Mechanical behavior is related to the structural modifications. A temperature of 110 degrees C before, during, and after the in vacuum irradiation of UHMWPE produces a high amount of crosslinks and improves polymeric tensile and wear resistance, compared to that of the untreated material.

  15. A novel gas-vacuum interface for environmental molecular beam studies.

    PubMed

    Johansson, Sofia M; Kong, Xiangrui; Papagiannakopoulos, Panos; Thomson, Erik S; Pettersson, Jan B C

    2017-03-01

    Molecular beam techniques are commonly used to obtain detailed information about reaction dynamics and kinetics of gas-surface interactions. These experiments are traditionally performed in vacuum and the dynamic state of surfaces under ambient conditions is thereby excluded from detailed studies. Herein we describe the development and demonstration of a new vacuum-gas interface that increases the accessible pressure range in environmental molecular beam (EMB) experiments. The interface consists of a grating close to a macroscopically flat surface, which allows for experiments at pressures above 1 Pa including angularly resolved measurements of the emitted flux. The technique is successfully demonstrated using key molecular beam experiments including elastic helium and inelastic water scattering from graphite, helium and light scattering from condensed adlayers, and water interactions with a liquid 1-butanol surface. The method is concluded to extend the pressure range and flexibility in EMB studies with implications for investigations of high pressure interface phenomena in diverse fields including catalysis, nanotechnology, environmental science, and life science. Potential further improvements of the technique are discussed.

  16. A novel gas-vacuum interface for environmental molecular beam studies

    NASA Astrophysics Data System (ADS)

    Johansson, Sofia M.; Kong, Xiangrui; Papagiannakopoulos, Panos; Thomson, Erik S.; Pettersson, Jan B. C.

    2017-03-01

    Molecular beam techniques are commonly used to obtain detailed information about reaction dynamics and kinetics of gas-surface interactions. These experiments are traditionally performed in vacuum and the dynamic state of surfaces under ambient conditions is thereby excluded from detailed studies. Herein we describe the development and demonstration of a new vacuum-gas interface that increases the accessible pressure range in environmental molecular beam (EMB) experiments. The interface consists of a grating close to a macroscopically flat surface, which allows for experiments at pressures above 1 Pa including angularly resolved measurements of the emitted flux. The technique is successfully demonstrated using key molecular beam experiments including elastic helium and inelastic water scattering from graphite, helium and light scattering from condensed adlayers, and water interactions with a liquid 1-butanol surface. The method is concluded to extend the pressure range and flexibility in EMB studies with implications for investigations of high pressure interface phenomena in diverse fields including catalysis, nanotechnology, environmental science, and life science. Potential further improvements of the technique are discussed.

  17. Concentrated atmospheric nanoparticle beams in vacuum for X-ray and optical spectroscopy.

    NASA Astrophysics Data System (ADS)

    Meinen, J.; Khasminskaya, S.; Leisner, T.

    2009-04-01

    The IPCC AR4 points out the important role of aerosol in the radiation budget of the earth. In the model prediction, direct and indirect contribution of the atmospheric aerosol causes a net cooling of the earth. Understanding the fundamental physical and chemical processes of heterogeneous nucleation of water on nanoparticles could help improving the models. On our poster we present the first stage of the TRAPS apparatus (Trapped Reactive Atmospheric Particle Spectrometer). The apparatus comprises as nanoparticle sources atomizers, electrospray and plasma reactors in order to produce nanoparticle sizes from 20-50nm, 10-20nm and 5-10nm respectively. The nanoparticles are dispersed in helium as carrier gas at high pressure. After passing a critical orifice into rough vacuum a tunable aerodynamic lens is used to focus the particles into a differential pumping stage. We put high effort in optimizing the aerodynamic lens for particle beams close to the diffusion limit by CFD calculations. Downstream the differential pumping the particle beam is used to continuously refill a linear ion trap. For the trapping of particles in the size range of several kDa to MDa, a radio frequency from 10-150 kHz is. In contrast to the work of other groups, which are using digital ion traps, we developed an amplifier capable to provide an appropriate sinusoidal voltage with amplitude up to 3kV. This assembly is capable to inject nanoparticles into vacuum chambers in a highly efficient way. The dilution of the particle number concentration arising from the gas expansion from room pressure into vacuum is compensated by concentrating the particles in a small cylindrical volume by electrodynamic trapping. The enlargement of the target density compared to a free molecular beam provides a tool for various techniques of spectroscopy used on smaller ions by routine.

  18. Improving ion beam injector performance by augmenting capacitance of vacuum diode

    SciTech Connect

    Goerz, D. A., LLNL

    1998-06-24

    The recirculating induction accelerator is a new class of particle accelerator being developed at LLNL as a reduced-cost driver for heavy-ion beam driven inertial fusion energy. Ongoing research and development of advanced beam control technologies for the recirculator system requires a very stable and reproducible ion beam source. The injector pulse modulator must be capable of producing very precise high-voltage pulses in order to reduce the current modulation instability and achieve the required beam reproducibility. Computer modeled simulations of beam dynamics have established that errors greater than 0.1 percent in the flatness of the 120 kV injector pulse can create intolerable energy deviations. The pulse modulator that was developed to satisfy the stringent requirements is described in the accompanying paper by Wilson [1]. A crucial aspect of the overall solution is a modification made to the vacuum diode apparatus, whereby high-voltage capacitors were added in close proximity to the thermionic potassium-ion emitter. This paper discusses the rationale for augmenting the normally small capacitance of the injector diode, and presents design information, including an illustrated layout, electrostatic field modeling results, and data on ceramic capacitors operating at elevated levels.

  19. Development of fast heating electron beam annealing setup for ultra high vacuum chamber.

    PubMed

    Das, Sadhan Chandra; Majumdar, Abhijit; Katiyal, Sumant; Shripathi, T; Hippler, R

    2014-02-01

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10(-6) mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  20. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    SciTech Connect

    Das, Sadhan Chandra; Majumdar, Abhijit E-mail: majumdar@uni-greifswald.de; Hippler, R.; Katiyal, Sumant; Shripathi, T.

    2014-02-15

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10{sup −6} mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  1. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    NASA Astrophysics Data System (ADS)

    Das, Sadhan Chandra; Majumdar, Abhijit; Katiyal, Sumant; Shripathi, T.; Hippler, R.

    2014-02-01

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 °C with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (˜10-6 mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 °C of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  2. Boron ion beam generation utilizing lanthanum hexaboride cathodes: Comparison of vacuum arc and planar magnetron glow

    SciTech Connect

    Nikolaev, A. G.; Vizir, A. V.; Yushkov, G. Yu. Frolova, V. P.; Oks, E. M.

    2016-02-15

    Boron ion beams are widely used for semiconductor ion implantation and for surface modification for improving the operating parameters and increasing the lifetime of machine parts and tools. For the latter application, the purity requirements of boron ion beams are not as stringent as for semiconductor technology, and a composite cathode of lanthanum hexaboride may be suitable for the production of boron ions. We have explored the use of two different approaches to boron plasma production: vacuum arc and planar high power impulse magnetron in self-sputtering mode. For the arc discharge, the boron plasma is generated at cathode spots, whereas for the magnetron discharge, the main process is sputtering of cathode material. We present here the results of comparative test experiments for both kinds of discharge, aimed at determining the optimal discharge parameters for maximum yield of boron ions. For both discharges, the extracted ion beam current reaches hundreds of milliamps and the fraction of boron ions in the total extracted ion beam is as high as 80%.

  3. Magnetic latches provide positive overpressure control

    NASA Technical Reports Server (NTRS)

    Loy, J. L.

    1966-01-01

    Louvers are used for overpressure safety venting in rooms or chambers where explosion hazards exist. The louvers have individually hinged closures that are held in locked position by commercially available magnets that quickly release them in an overpressure condition.

  4. Modification of a high vacuum, crossed molecular beam scattering system to perform angle-resolved, gas-surface scattering studies under ultrahigh vacuum conditions

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Hiroshi; Ohashi, Haruhiko; Tabayashi, Kiyohiko; Suzui, Mitsukazu; Horigome, Toshio; Hayakawa, Kazuo; Kato, Shinji; Shobatake, Kosuke; Ito, Koji; Fujimoto, Tetsuo

    1999-03-01

    A molecular beam apparatus which was formerly used for crossed molecular beam chemiluminescence experiments under high vacuum conditions has been modified into an ultrahigh vacuum apparatus with a rotatable mass spectrometer detector equipped with an electron bombardment ionizer to study (1) the molecule-surface scattering process, (2) molecular beam-surface reaction dynamics, and (3) light-excited molecular desorption. Every flange surface originally sealed using a Viton o ring is sealed with a combination of an inner spring-loaded Teflon or aluminum seal with an outer Viton o ring, the intermediate region being pumped with a diffusion pump. Due to the limited space available for a rotatable detector chamber and to make the neutral flight length in time-of-flight (TOF) measurements as long as possible, the electron bombardment ionizer is installed at the farthest end of a triply differentially pumped detector chamber; thus, the ions formed are extracted toward the reverse direction of the scattered neutral molecular beam, mass selected with a quadrupole mass filter, and detected by an electron multiplier. Using this apparatus, angular and TOF distributions have been measured for Xe scattered from crystalline graphite surface and for the desorbed product, SiCl2, from the etching reaction of Si(111) with a beam of hyperthermal Cl2 molecules.

  5. Kinetics of Evaporation of Alloying Elements under Vacuum: Application to Ti alloys in Electron Beam Melting

    NASA Astrophysics Data System (ADS)

    Choi, Wonjin; Jourdan, Julien; Matveichev, Alexey; Jardy, Alain; Bellot, Jean-Pierre

    2017-09-01

    Vacuum metallurgical processes such as the electron beam melting are highly conducive to volatilization. In titanium processing, it concerns the alloying elements which show a high vapor pressure with respect to titanium matrix, such as Al. Two different experimental approaches using a laboratory electron beam furnace have been developed for the estimation of volatilization rate and activity coefficient of Al in Ti64. The first innovative method is based on the deposition rate of Al on Si wafers located at different angles θ above the liquid bath. We found that a deposition according to a cos2(π/2-θ) law describes well the experimental distribution of the weight of the deposition layer. The second approach relies on the depletion of aluminum in the liquid pool at two separate times of the volatilization process. Both approaches provide values of the Al activity coefficient at T=1, 860 °C in a fairly narrow range [0.044-0.0495], in good agreement with the range reported in the literature. Furthermore numerical simulation of the Al behavior in the liquid pool reveals (in the specific case of electron beam button melting) a weak transport resistance in the surface boundary layer.

  6. Direct acceleration of an electron in infinite vacuum by a pulsed radially-polarized laser beam.

    PubMed

    Wong, Liang Jie; Kärtner, Franz X

    2010-11-22

    We study the direct acceleration of a free electron in infinite vacuum along the axis of a pulsed radially-polarized laser beam. We find that net energy transfer from laser pulse to electron is maximized with the tightest focusing. We show that the net energy gain of an electron initially moving at a relativistic velocity may exceed more than half the theoretical limit of energy transfer, which is not possible with an initially stationary electron in the parameter space studied. We determine and analyze the power scaling of maximum energy gain, extending our study to include a relatively unexplored regime of low powers and revealing that substantial acceleration is already possible without the use of petawatt peak-power laser technology.

  7. Secondary ion yields for vacuum-type electrospray droplet beams measured with a triple focus time-of-flight analyzer.

    PubMed

    Ninomiya, Satoshi; Sakai, Yuji; Watanabe, Ryo; Sogou, Mauo; Miyayama, Takuya; Sakai, Daisuke; Watanabe, Katsumi; Chen, Lee Chuin; Hiraoka, Kenzo

    2016-10-30

    We previously developed a massive cluster ion beam gun for secondary ion mass spectrometry (SIMS) in which the primary beam source is a vacuum electrospray. The secondary ion yields produced by this method had not yet been measured with a commercial time-of-flight (TOF) secondary ion mass spectrometer, and the ionization performance was unknown. A vacuum-type electrospray droplet ion gun was connected to a triple-focus TOF analyzer. The flight time of the secondary ions was measured using a sample-bias pulsing method, because a short pulse of the electrospray droplet beam could not be obtained. The secondary ion yields of an amino acid sample produced by the electrospray droplet beams and atomic Ga ion beams were compared. TOF secondary ion spectra were measured for the amino acid and peptide samples with a mass resolution of ~500 using the sample-bias pulsing method. The secondary ion yield of the amino acid sample produced with the 10 kV vacuum-type electrospray droplet beams was much higher than that produced by 10 kV Ga ion beams. In addition, the secondary ion yields for the peptide sample and amino acid samples were almost similar. This is the first report on secondary ion yields produced with vacuum-type electrospray droplet ion beams and measured with a semi-commercial TOF analyzer. The enhancement of secondary ion yields, in particular for relatively high-mass molecules, would be very useful in the SIMS analysis of a wide variety of biological samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Generation of EM radiations using intense electron beam produced in vacuum

    SciTech Connect

    Shukla, R.; Shyam, A.; Verma, R.; Deb, P.; Mishra, E.; Meena, M.

    2014-07-01

    The results of a pulse power generator driving an axial virtual cathode oscillator are being presented in this paper as a source of high power microwave (HPM) radiations. The electron beam generator is also modified to attain the intense X-ray burst. The pulse power generator used for these applications is common and is having 10 ohms as its characteristic impedance with 50nS of pulse width. The peak charging voltage of the pulse forming line is 450 kV and hence 225 kV and 22.5 kA is peak voltage and peak current delivery capabilities respectively for the pulse power generator. The peak electrical power of the generator is 5GW for a matched load. The charging power supply for the pulse forming line consists of a high voltage generator made by pulse transformer and charging the pulse forming line in the first cycle of the charging pulse. To utilize the energy of the primary capacitive storage efficiently the pulse transformer is having 0.8 coupling coefficient between its primary and the secondary. The axial vircator chamber is evacuated to attain the vacuum of 2 x 10{sup -4} torr for the HPM application. In the case of modified electron beam chamber for the generation of X-rays the vacuum of same order is used. The pulse forming line is made using equal lengths of high voltage transmission lines, each having a length of 10 meters, connected in the parallel to give a net source impedance of 10 ohm. The pulse power generator can operate in repetitive mode and hence the HPM as well as X-rays may be generated in the repetitive burst. (author)

  9. Component analysis of a mixed beam generated by vacuum electrospray of an ionic liquid

    SciTech Connect

    Fujiwara, Yukio; Saito, Naoaki; Nonaka, Hidehiko; Ichimura, Shingo

    2012-03-15

    Vacuum electrospray of a quaternary ammonium ionic liquid, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl) amide (DEME-TFSA), was investigated to develop a primary ion source for secondary ion mass spectrometry (SIMS). Since the ionic liquid contains many methyl and ethyl groups as well as protons, its beam is expected to efficiently produce protonated molecules for SIMS analysis of organic materials. Experimental results showed that the beam consisted of charged particles of m/z about 1000 and charged droplets of m/z > 10{sup 5}. The current components of both the charged particles and droplets changed with the applied voltage and the flow rate of the ionic liquid. With decreasing flow rate, the current component of the charged droplets increased, whereas that of the charged particles decreased. The m/z values of the charged droplets diminished with decreasing flow rate and increasing capillary voltage. In addition to masses and charge numbers, the numbers of the charged droplets and the charged particles were estimated.

  10. SPEAKING IN LIGHT - Jupiter radio signals as deflections of light-emitting electron beams in a vacuum chamber

    NASA Astrophysics Data System (ADS)

    Petrovic, K.

    2015-10-01

    Light emitting electron beam generated in a vacuum chamber is used as a medium for visualizing Jupiter's electromagnetic radiation. Dual dipole array antenna is receiving HF radio signals that are next amplified to radiate a strong electromagnetic field capable of influencing the propagation of electron beam in plasma. Installation aims to provide a platform for observing the characteristics of light emitting beam in 3D, as opposed to the experiments with cathode ray tubes in 2-dimensional television screens. Gas giant 'speaking' to us by radio waves bends the light in the tube, allowing us to see and hear the messages of Jupiter - God of light and sky.

  11. Vacuum channeling radiation by relativistic electrons in a transverse field of a laser-based Bessel beam.

    PubMed

    Schächter, L; Kimura, W D

    2015-05-15

    Relativistic electrons counterpropagating through the center of a radially polarized J_{1} optical Bessel beam in vacuum will emit radiation in a manner analogous to the channeling radiation that occurs when charged particles traverse through a crystal lattice. However, since this interaction occurs in vacuum, problems with scattering of the electrons by the lattice atoms are eliminated. Contrary to inverse Compton scattering, the emitted frequency is also determined by the amplitude of the laser field, rather than only by its frequency. Adjusting the value of the laser field permits the tuning of the emitted frequency over orders of magnitude, from terahertz to soft X rays. High flux intensities are predicted (~100 MW/cm^{2}). Extended interaction lengths are feasible due to the diffraction-free properties of the Bessel beam and its radial field, which confines the electron trajectory within the center of the Bessel beam.

  12. Peak Overpressures for Internal Blast

    DTIC Science & Technology

    1979-06-01

    reactions such as formation of aluminum oxide. The slow pressure-decay rates for internal explosions leid to relatively long overpressure duration times that...1750 6.61 2205 .21 7.9 5.59 1941 7.19 2408 .18 6.9 6.13 2007 7.70 2643 .23 9.4 6.23 2122 7.89 2586 .23 9.4 5.45 2186 7.89 25Ś .17 9.4 6.23 2124 7.89

  13. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap.

    PubMed

    Nikolaev, A G; Savkin, K P; Oks, E M; Vizir, A V; Yushkov, G Yu; Vodopyanov, A V; Izotov, I V; Mansfeld, D A

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap--axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  14. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trapa)

    NASA Astrophysics Data System (ADS)

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-01

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent "minimum-B" structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 μs) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  15. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap

    SciTech Connect

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-15

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  16. Leak Rate Test for a Fiber Beam Monitor Contained in a Vacuum for the Muon g-2 Experiment

    NASA Astrophysics Data System (ADS)

    O'Mara, Bridget; Lane, Noel; Gross, Eisen; Gray, Frederick; Muon g-2 Collaboration

    2014-09-01

    The muon g-2 experiment at Fermilab aims to measure the muon anomalous magnetic moment with a precision of 0.14 parts per million (ppm). The measurement will build on the Brookhaven-based E821 experiment, which yielded results suggesting new physics such as supersymmetry. The Fiber Beam Monitors (FBMs) are used in the experiment to determine the position and observe the motion of a muon beam and monitor the properties of the beam over time. The FBMs support a 9 cm × 8 cm ``harp'' with 7 scintillating fibers separated from each other by 13 mm, each with a diameter of 0.5 mm. The experiment requires a vacuum of less than 1 ×10-6 Torr to prevent trapping of electrons ionized from the residual gas by the electrostatic quadrupoles. To meet this requirement the FBMs must have a leak rate of less than 5 ×10-5 Torr L/s. We have constructed a vacuum system to simulate these conditions and have determined the leak rate of the FBMs within the constructed vacuum apparatus. This leak rate will be reported, along with preliminary results from tests of the light output from the scintillating fibers. The muon g-2 experiment at Fermilab aims to measure the muon anomalous magnetic moment with a precision of 0.14 parts per million (ppm). The measurement will build on the Brookhaven-based E821 experiment, which yielded results suggesting new physics such as supersymmetry. The Fiber Beam Monitors (FBMs) are used in the experiment to determine the position and observe the motion of a muon beam and monitor the properties of the beam over time. The FBMs support a 9 cm × 8 cm ``harp'' with 7 scintillating fibers separated from each other by 13 mm, each with a diameter of 0.5 mm. The experiment requires a vacuum of less than 1 ×10-6 Torr to prevent trapping of electrons ionized from the residual gas by the electrostatic quadrupoles. To meet this requirement the FBMs must have a leak rate of less than 5 ×10-5 Torr L/s. We have constructed a vacuum system to simulate these conditions

  17. Vacuum tube operation analysis under multi-harmonic driving and heavy beam loading effect in J-PARC RCS

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Nomura, M.; Shimada, T.; Tamura, F.; Hara, K.; Hasegawa, K.; Ohmori, C.; Toda, M.; Yoshii, M.; Schnase, A.

    2016-11-01

    An rf cavity in the J-PARC RCS not only covers the frequency range of a fundamental acceleration pattern but also generates multi-harmonic rf voltage because it has a broadband impedance. However, analyzing the vacuum tube operation in the case of multi-harmonics is very complicated because many variables must be solved in a self-consistent manner. We developed a method to analyze the vacuum tube operation using a well-known formula and which includes the dependence on anode current for some variables. The calculation method is verified with beam tests, and the results indicate that it is efficient under condition of multi-harmonics with a heavy beam loading effect.

  18. Conceptual Design of Vacuum Chamber for testing of high heat flux components using electron beam as a source

    NASA Astrophysics Data System (ADS)

    Khan, M. S.; Swamy, Rajamannar; Khirwadkar, S. S.; Divertors Division, Prototype

    2012-11-01

    A conceptual design of vacuum chamber is proposed to study the thermal response of high heat flux components under energy depositions of the magnitude and durations expected in plasma fusion devices. It is equipped with high power electron beam with maximum beam power of 200 KW mounted in a stationary horizontal position from back side of the chamber. The electron beam is used as a heat source to evaluate the heat removal capacity, material performance under thermal loads & stresses, thermal fatigue etc on actively cooled mock - ups which are mounted on a flange system which is the front side door of the chamber. The tests mock - ups are connected to a high pressure high temperature water circulation system (HPHT-WCS) operated over a wide range of conditions. The vacuum chamber consists of different ports at different angles to view the mock -up surface available for mock -up diagnostics. The vacuum chamber is pumped with different pumps mounted on side ports of the chamber. The chamber is shielded from X - rays which are generated inside the chamber when high-energy electrons are incident on the mock-up. The design includes development of a conceptual design with theoretical calculations and CAD modelling of the system using CATIA V5. These CAD models give an outline on the complete geometry of HHF test chamber, fabrication challenges and safety issues. FEA analysis of the system has been performed to check the structural integrity when the system is subjected to structural & thermal loads.

  19. An ultra-low energy (30-200 eV) ion-atomic beam source for ion-beam-assisted deposition in ultrahigh vacuum

    SciTech Connect

    Mach, Jindrich; Kolibal, Miroslav; Sikola, Tomas; Samoril, Tomas; Voborny, Stanislav; Zlamal, Jakub; Spousta, Jiri; Dittrichova, Libuse

    2011-08-15

    The paper describes the design and construction of an ion-atomic beam source with an optimized generation of ions for ion-beam-assisted deposition under ultrahigh vacuum (UHV) conditions. The source combines an effusion cell and an electron impact ion source and produces ion beams with ultra-low energies in the range from 30 eV to 200 eV. Decreasing ion beam energy to hyperthermal values ({approx_equal}10{sup 1} eV) without loosing optimum ionization conditions has been mainly achieved by the incorporation of an ionization chamber with a grid transparent enough for electron and ion beams. In this way the energy and current density of nitrogen ion beams in the order of 10{sup 1} eV and 10{sup 1} nA/cm{sup 2}, respectively, have been achieved. The source is capable of growing ultrathin layers or nanostructures at ultra-low energies with a growth rate of several MLs/h. The ion-atomic beam source will be preferentially applied for the synthesis of GaN under UHV conditions.

  20. Apparatus for reducing shock and overpressure

    DOEpatents

    Walter, C.E.

    1975-01-28

    An apparatus for reducing shock and overpressure is particularly useful in connection with the sequential detonation of a series of nuclear explosives under ground. A coupling and decoupling arrangement between adjacent nuclear explosives in the tubing string utilized to emplace the explosives is able to support lower elements on the string but yields in a manner which absorbs energy when subjected to the shock wave produced upon detonation of one of the explosives. Overpressure is accomodated by an arrangement in the string which provides an additional space into which the pressurized material can expand at a predetermined overpressure. (10 claims)

  1. Apparatus for reducing shock and overpressure

    DOEpatents

    Walter, C.E.

    1975-10-21

    The design is given of an apparatus for reducing shock and overpressure particularly useful in connection with the sequential detonation of a series of nuclear explosives underground. A coupling and decoupling arrangement between adjacent nuclear explosives in the tubing string utilized to emplace the explosives is able to support lower elements on the string but yields in a manner which absorbs energy when subjected to the shock wave produced upon detonation of one of the explosives. Overpressure is accommodated by an arrangement in the string which provides an additional space into which the pressurized material can expand at a predetermined overpressure.

  2. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    NASA Astrophysics Data System (ADS)

    Manova, D.; Bergmann, A.; Mändl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-01

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton® windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  3. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber.

    PubMed

    Manova, D; Bergmann, A; Mändl, S; Neumann, H; Rauschenbach, B

    2012-11-01

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton(®) windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  4. Integration of a broad beam ion source with a high-temperature x-ray diffraction vacuum chamber

    SciTech Connect

    Manova, D.; Bergmann, A.; Maendl, S.; Neumann, H.; Rauschenbach, B.

    2012-11-15

    Here, the integration of a low energy, linearly variable ion beam current density, mechanically in situ adjustable broad beam ion source with a high-temperature x-ray diffraction (XRD) vacuum chamber is reported. This allows in situ XRD investigation of phase formation and evolution processes induced by low energy ion implantation. Special care has been taken to an independent adjustment of the ion beam for geometrical directing towards the substrate, a 15 mm small ion source exit aperture to avoid a secondary sputter process of the chamber walls, linearly variable ion current density by using a pulse length modulation (PLM) for the accelerating voltages without changing the ion beam density profile, nearly homogeneous ion beam distribution over the x-ray footprint, together with easily replaceable Kapton{sup Registered-Sign} windows for x-rays entry and exit. By combining a position sensitive x-ray detector with this PLM-modulated ion beam, a fast and efficient time resolved investigation of low energy implantation processes is obtained in a compact experimental setup.

  5. Ultrahigh vacuum and low-temperature cleaning of oxide surfaces using a low-concentration ozone beam

    SciTech Connect

    Pratt, A.; Graziosi, P.; Bergenti, I.; Dediu, A.; Prezioso, M.; Yamauchi, Y.

    2014-07-15

    We present a novel method of delivering a low-concentration (<15%) ozone beam to an ultra-high vacuum environment for the purpose of cleaning and dosing experimental samples through oxidation processing. The system described is safe, low-cost, and practical and overcomes the limitations of ozone transport in the molecular flow environment of high or ultrahigh vacuum whilst circumventing the use of pure ozone gas which is potentially highly explosive. The effectiveness of this method in removing surface contamination is demonstrated through comparison of high-temperature annealing of a simple oxide (MgO) in ozone and oxygen environments as monitored using quadrupole mass spectroscopy and Auger electron spectroscopy. Additionally, we demonstrate the potential of ozone for obtaining clean complex oxide surfaces without the need for high-temperature annealing which may significantly alter surface structure.

  6. Electrical conductivity of cluster-assembled carbon/titania nanocomposite films irradiated by highly focused vacuum ultraviolet photon beams

    SciTech Connect

    Amati, M.; Lenardi, C.; Agostino, R. G.; Caruso, T.; Ducati, C.; La Rosa, S.; Bongiorno, G.; Cassina, V.; Podesta, P.; Ravagnan, L.; Piseri, P.; Milani, P.

    2007-03-15

    We investigated the electrical transport properties of nanostructured carbon and carbon/titanium oxide nanocomposite films produced by supersonic cluster beam deposition and irradiated by highly focused vacuum UV photon beam. We have observed a relevant increase of the density of states at Fermi level, suggesting that the films acquire a 'metallic' character. This is confirmed by the increment of the conductivity of four orders of magnitude for pure nanostructured carbon films and at least eight orders of magnitude for films containing 9 at. % of titanium. A partial reversibility of the process is observed by exposing the modified films to molecular oxygen or directly to air. We demonstrate the capability of writing micrometric conductive strips (2-3 {mu}m width and 60 {mu}m length) and controlling the variation of the conductivity as a function of the titanium concentration.

  7. Effects of vacuum annealing and oxygen ion beam bombarding on the electrical and optical properties of ITO films deposited by E-beam evaporation

    NASA Astrophysics Data System (ADS)

    Pan, Yongqiang; Hang, Lingxia

    2012-10-01

    Tin doped indium oxide (ITO) transparent conductive thin films with composition of 10 wt% SnO2 and 89.8 wt% In2O3 have been deposited by electron beam evaporation technique on K9 glass substrates at room temperature. The post annealing processes are done in vacuum with different annealing temperature at 100, 200, 300 and 350 ° for 1 hour, respectively. The oxygen ion energy is 800 eV; oxygen ion beam bombarding time is 10,20,30,40 and 50min, respectively. The results show that conductivity of ITO thin films are improved by increasing annealing temperature. The resistivity of the ITO thin films decrease from 5.2×10-3Ω •cm at room temperature to 1.3×10-3Ω •cm(350 °C). The transmittance values of all samples in the visible range have been increased. As the oxygen ion beam bombarding time increases the resistivity reduce from 5.2×10-3Ω •cm to 9×10-4Ω •cm, the transmittance value improve from 66% to 82% at 550nm. Finally, the vacuum annealing and oxygen ion beam bombarding are done simultaneously, at temperature of 350 °C for 1 hours, ion bombardment time for 40 min. The resistivity of obtained ITO thin film is 7×10-4Ω •cm. The maximum transmittance value is above 89% in the visible wavelength region.

  8. Study of Damage of Storage Ring Vacuum Chamber by 8 GeV Electron Beam Abort at SPring-8

    NASA Astrophysics Data System (ADS)

    Yorita, Tetsuhiko; Ohishi, Masaya; Kumagai, Noritaka; Ohkuma, Haruo; Yonehara, Hiroto; Schimizu, Jun; Tanaka, Hitoshi

    The 8 GeV electron beam stored on the SPring-8 storage ring finally hits the vacuum chamber wall, especially stainless steel chamber wall of 0.7 mm thickness in the injection section, when the operation is suddenly stopped by interlock system for safety. At that time the localized heat load is generated in the stainless steel material as a result of the dense electro-magnetic shower. Because of the several times such heat loads, the stainless steel chamber has been broken and vacuum also has. On the cross section of the broken stainless steel wall, one can see the evidence of the degeneration or melting down of the stainless steel which is well described by the cascade calculation for the high energy electro-magnetic events using GEANT31). To avoid such a vacuum break, a thicker stainless steel chamber has been installed and an Al damper, in which density of electro-magnetic shower is low because of its small atomic number, has been developed.

  9. Heavy ion beam degradation from stripping in near vacuum reactor chambers

    SciTech Connect

    Barletta, W.A.

    1981-07-21

    With the use of a particle simulation code we have investigated the ballistic transport of heavy ion beams through a gas-filled reactor for inertial confinement fusion. The background gas pressure has been taken to be 10/sup -4/ torr - 10/sup -3/ torr of Lithium vapor as is appropriate to the HYLIFE reactor concept. During transport to the pellet, Coulomb collisions of beam particles with the background gas will convert a fraction of the beam to charges states higher than the initial value. Collisons will also produce an associated swarm of knock-on electrons. As the beam approaches the pellet, anharmonic components of the space charges forces will lead to a distortion of the phase space of the beam and a consequent degradation of the focal properties of the beam. This degradation can be described in terms of an increase in the rms emittance of the beam. The degree of emittance growth depends sensitivity upon the initial spatial distribution of particles in the beam. For this study we have modified a single-disk particle simulation code, DESTIN (2), to follow two species of particles, the number of which varies in a prescribed fashion dependent upon reactor temperature as the beam converges toward the pellet.

  10. Measuring of plasma properties induced by non-vacuum electron beam welding

    SciTech Connect

    Reisgen, U.; Schleser, M.; Abdurakhmanov, A.; Gumenyuk, A.

    2012-01-15

    Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic.

  11. Measuring of plasma properties induced by non-vacuum electron beam welding

    NASA Astrophysics Data System (ADS)

    Reisgen, U.; Schleser, M.; Abdurakhmanov, A.; Gumenyuk, A.

    2012-01-01

    Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic.

  12. Investigation of the thermally induced laser beam distortion associated with vacuum compressor gratings in high energy and high average power femtosecond laser systems

    PubMed Central

    Fourmaux, S.; Serbanescu, C.; Lecherbourg, L.; Payeur, S.; Martin, F.; Kieffer, J. C.

    2009-01-01

    We report successful compensation of the thermally induced laser beam distortion associated with high energy 110 mJ and high average power femtosecond laser system of 11 Watts operated with vacuum compressor gratings. To enhance laser-based light source brightness requires development of laser systems with higher energy and higher average power. Managing the high thermal loading on vacuum optical components is a key issue in the implementation of this approach. To our knowledge this is the first time that such thermal induced distortions on the vacuum compressor gratings are characterized and compensated. PMID:19129886

  13. Investigation of the thermally induced laser beam distortion associated with vacuum compressor gratings in high energy and high average power femtosecond laser systems.

    PubMed

    Fourmaux, S; Serbanescu, C; Lecherbourg, L; Payeur, S; Martin, F; Kieffer, J C

    2009-01-05

    We report successful compensation of the thermally induced laser beam distortion associated with high energy 110 mJ and high average power femtosecond laser system of 11 Watts operated with vacuum compressor gratings. To enhance laser-based light source brightness requires development of laser systems with higher energy and higher average power. Managing the high thermal loading on vacuum optical components is a key issue in the implementation of this approach. To our knowledge this is the first time that such thermal induced distortions on the vacuum compressor gratings are characterized and compensated.

  14. Increasing the electric strength of vacuum insulation by treating the electrodes with a low-energy, high-current electron beam

    SciTech Connect

    Batrakov, A.V.; Nazarov, D.S.; Ozur, G.E.

    1996-12-31

    The paper is devoted to the study of how the irradiation of the electrode surface with a low-energy, high-current electron beam affects the prebreakdown current and the electric strength of the vacuum insulation. This study is an extension of the work whose results were presented at the XVI ISDEIV. Experiments have been performed for 0.1-mm vacuum gaps formed by refractory-metal electrodes and for millimeter vacuum gaps with a pulsed voltage of amplitude 250 kV and duration 30-100 ns.

  15. In-vacuum sensors for the beamline components of the ITER neutral beam test facility

    SciTech Connect

    Dalla Palma, M. Pasqualotto, R.; Spagnolo, S.; Spolaore, M.; Sartori, E.; Veltri, P.

    2016-11-15

    Embedded sensors have been designed for installation on the components of the MITICA beamline, the prototype ITER neutral beam injector (Megavolt ITER Injector and Concept Advancement), to derive characteristics of the particle beam and to monitor the component conditions during operation for protection and thermal control. Along the beamline, the components interacting with the particle beam are the neutralizer, the residual ion dump, and the calorimeter. The design and the positioning of sensors on each component have been developed considering the expected beam-surface interaction including non-ideal and off-normal conditions. The arrangement of the following instrumentation is presented: thermal sensors, strain gages, electrostatic probes including secondary emission detectors, grounding shunt for electrical currents, and accelerometers.

  16. In-vacuum sensors for the beamline components of the ITER neutral beam test facility

    NASA Astrophysics Data System (ADS)

    Dalla Palma, M.; Pasqualotto, R.; Sartori, E.; Spagnolo, S.; Spolaore, M.; Veltri, P.

    2016-11-01

    Embedded sensors have been designed for installation on the components of the MITICA beamline, the prototype ITER neutral beam injector (Megavolt ITER Injector and Concept Advancement), to derive characteristics of the particle beam and to monitor the component conditions during operation for protection and thermal control. Along the beamline, the components interacting with the particle beam are the neutralizer, the residual ion dump, and the calorimeter. The design and the positioning of sensors on each component have been developed considering the expected beam-surface interaction including non-ideal and off-normal conditions. The arrangement of the following instrumentation is presented: thermal sensors, strain gages, electrostatic probes including secondary emission detectors, grounding shunt for electrical currents, and accelerometers.

  17. Non-vacuum electron-beam carburizing and surface hardening of mild steel

    NASA Astrophysics Data System (ADS)

    Bataev, I. A.; Golkovskii, M. G.; Losinskaya, A. A.; Bataev, A. A.; Popelyukh, A. I.; Hassel, T.; Golovin, D. D.

    2014-12-01

    In this paper, we study the structure, microhardness, and tribological properties of surface layers of mild (0.19% C) steel, which was formed by electron-beam cladding with an iron-graphite powder mixture followed by quenching and tempering. A 1.4 MeV electron beam that was extracted into air was used. Cladding of steel with the iron-graphite mixture at a beam current of 24 and 26 mA formed a hypoeutectic cast iron layer (2.19% C) and a hypereutectoid steel (1.57% C) layer, which were 2.0 and 2.6 mm thick, respectively. The microhardness of the surface-quenched and tempered steel and cast iron layers was 7 and 8 GPa, respectively. Electron-beam quenching of the surface layers of hypoeutectic cast iron was accompanied with multiple cracking. During the quenching of the 1.57% C steel layer, crack formation was not observed. In friction tests against fixed and loose abrasive particles, the surface layers of hypereutectoid steel and hypoeutectic cast iron that were produced by electron-beam cladding and quenching had lower wear rates than mild steel after pack carburizing, quenching, and tempering. In the sliding wear tests, the cast iron clad layer, which was subjected to electron-beam quenching and tempering, exhibited the highest wear resistance. Electron-beam treatment can be used to harden local areas of large workpieces. It is reasonable to treat clad layers of high-carbon steel with electron-beam quenching and tempering. To prevent multiple cracking, white cast iron layers should not be quenched.

  18. Housing protects laser in vacuum

    NASA Technical Reports Server (NTRS)

    Canali, V. G.

    1978-01-01

    Airtight housing encloses laser for easy alinement and operation in high-vacuum chamber. Beam is transmitted through window into vacuum chamber. Flexible line runs through vacuum chamber to outside, maintaining laser enclosure at atmospheric pressure.

  19. Glacially Generated Overpressure Offshore Massachusetts, USA: Integration of Full Seismic Waveform Inversion and Overpressure Modeling

    NASA Astrophysics Data System (ADS)

    Siegel, J. E.; Lizarralde, D.; Dugan, B.; Person, M. A.

    2012-12-01

    Localized, high-amplitude reflections, overlying a late Pleistocene glacial erosion surface 100 km offshore Massachusetts, USA, have lower compressional wave velocities of up to 200 m/s compared to adjacent sediments of equal depth. This may be the result of lower effective stress from overpressures as high as 1 MPa. To investigate the origin of these low velocity zones, we compare the detailed velocity structure across the high-amplitude regions to adjacent, undisturbed regions through a full waveform inversion, and we forward model the effective stress and overpressure. We relate the full waveform inversion velocities to effective stress with a power-law model. This model predicts effective stresses are 0.6 MPa at 250 m below the sea floor, which equates to an overpressure of 1.0 MPa. To help understand the overpressure source, we model the pressure response to erosion, glacial loading, and sedimentation in 1D. Preliminary models show that late Pleistocene glaciations, including the Last Glacial Maximum (LGM), and rapid sedimentation from glacial lake drainage may be important mechanisms for the generation of the localized regions of high overpressure. Our geophysical observations and interpretations suggest overpressure exists offshore today. Our forward models predict that this overpressure originated during the LGM due to pore pressure generation from rapid loading by glacial ice, however these overpressures are dissipating in the modern, low sedimentation rate environment. These shallow overpressures provide a mechanism to explain the SGD inferred along the Northern Atlantic continental shelf. Our results also provide physical-property observables, specific to location, that can constrain ongoing 3D numerical modeling efforts to deterministically predict the hydrologic history of the continental shelf sediments based on detailed stratigraphic and ice-sheet evolution.

  20. Beam Interaction Measurements with a Retarding Field Analyzer in a High-Current High-Vacuum Positively-Charged Particle Accelerator

    SciTech Connect

    Covo, M K; Molvik, A W; Friedman, A; Barnard, J J; Seidl, P A; Logan, B G; Baca, D; Vujic, J L

    2006-07-11

    A Retarding Field Analyzer (RFA) was inserted in a drift region of a magnetic transport section of the high-current experiment (HCX) that is at high-vacuum to measure ions and electrons resulting from beam interaction with background gas and walls. The ions are expelled during the beam by the space-charge potential and the electrons are expelled mainly at the end of the beam, when the beam potential decays. The ion energy distribution shows the beam potential of {approx} 2100 V and the beam-background gas total cross-section of 1.6x10{sup -20} m{sup 2}. The electron energy distribution reveals that the expelled electrons are mainly desorbed from the walls and gain {approx} 22 eV from the beam potential decaying with time before entering the RFA. Details of the RFA design and of the measured energy distributions are presented and discussed.

  1. Signal generator exciting an electromagnetic field for ion beam transport to the vacuum chamber of a mass spectrometer

    NASA Astrophysics Data System (ADS)

    Tubol'tsev, Yu. V.; Kogan, V. T.; Bogdanov, A. A.; Chichagov, Yu. V.; Antonov, A. S.

    2015-02-01

    A high-voltage high-frequency signal generator is described that excites an electric field for ion beam transport from an ion source to the vacuum chamber of a mass spectrometer. Excitation signals to the number of two are high-frequency sine-wave out-of-phase signals with the same amplitudes. The amplitude and phase of the signals vary from 20 to 100 V and from 10 kHz to 1 MHz, respectively. The generator also produces a controlled bias voltage in the interval 50-200 V. The frequency and amplitude of the signals, as well as the bias voltage, are computer-controlled via the USB interface.

  2. Structure and properties of Ti-C-B coatings produced by non-vacuum electron beam cladding

    NASA Astrophysics Data System (ADS)

    Lenivtseva, O. G.; Belousova, N. S.; Lozhkina, E. A.; Zimoglyadova, T. A.; Samoylenko, V. V.; Chuchkova, L. V.

    2016-11-01

    Cp-Ti/TiB+TiC wear-resistance coatings produced by non-vacuum electron beam cladding of boron carbide and titanium powders are studied in the paper. The X-ray phase analysis of the composite coatings microstructure showed that titanium carbide and boride reinforcing particles are evolved during the process. The obtained data are in good agreement with results of optical and electron microscopy. Undissolved particles of the initial boron carbide powder are detected in the coatings. The microhardness test as well as wear resistance test of materials under conditions of loose abrasive particles are conducted. It is established that the precipitation of reinforcing particles improves the tribological properties of the composite coatings.

  3. Structure and tribological properties of steel after non-vacuum electron beam cladding of Ti, Mo and graphite powders

    SciTech Connect

    Bataev, I.A.; Mul, D.O.; Bataev, A.A.; Lenivtseva, O.G.; Golkovski, M.G.; Lizunkova, Ya.S.; Dostovalov, R.A.

    2016-02-15

    The non-vacuum electron beam cladding technique was used to fabricate layers alloyed with Ti, Mo and C on the surface of low-alloyed steel. Two types of experiments were carried out. In the first experiment, a mixture of Ti and graphite powders was used for cladding; in the second, a mixture of Ti, Mo and graphite powders was used for cladding. CaF{sub 2} powder or a mixture of CaF{sub 2} and LiF powders was used as flux. The thickness of the cladded layers was in the range of 2–2.2 mm. The structure of the layers was studied using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The microhardness after cladding of the layers fabricated by cladding of Ti and graphite powders was 8–9 GPa, while the microhardness of layers with Mo additions reached 11–12 GPa. The highest wear resistance at sliding friction and friction in abrasive environment was reached in the samples fabricated using Ti, Mo and graphite mixture due to the higher hardness and the martensite–austenite structure of the matrix. The wear resistance against fixed abrasive particles was 2.4 times higher compared to that of carburized and quenched steel. - Highlights: • Ti, C and Mo mixture of powders was cladded using non-vacuum electron beam treatment. • The depth of the cladded layers was 2.0 … 2.2 mm. • The microhardness of layer with Mo, Ti and C additions reached ~ 11 … 12 GPa. • The hardening of the layers caused by the formation of TiC particles and martensitic matrix • Wear resistance of cladded coatings was 2.4 higher than carburized steel.

  4. 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.

  5. Note: A cryogenic, ultra-high-vacuum, microwave filter which passes a narrow beam

    SciTech Connect

    Evetts, N. Dosanjh, P.; Hardy, W. N.; Zvyagintsev, V.

    2015-12-15

    We report on a device which filters microwave radiation prone to heating cryogenic experiments while at the same time allowing large apertures which will not disturb a propagating beam. A method for evaporating thin films onto the inner face of a narrow tube is also described.

  6. Damping properties of a beam with vacuum-packed granular damper

    NASA Astrophysics Data System (ADS)

    Bajkowski, Jacek Mateusz; Dyniewicz, Bartłomiej; Bajer, Czesław I.

    2015-04-01

    An experimental study of the properties of a layered beam partially treated with a damping element based on a granular material is presented. The beam structure comprises two aluminium face strips connected at the tip by a hermetic, elastic envelope, filled with bulk granules. Changing the underpressure value inside the airtight envelope allows variation of the mechanical properties of such a complex system, like stiffness or damping coefficients. Four types of granules, different in size, shape, and material, were examined to find the most promising one. A detailed discussion of the experimental amplitude, frequency, and damping capacity of the cantilever is given. The Zener, Kelvin-Voigt, and classic Maxwell models were employed for modelling and parameter identification. The range of applicability and limitations of the proposed solution has been given, as well as the benefits from the application.

  7. X-ray diagnostic for current density profiling relativistic electron beams in vacuum and gas

    SciTech Connect

    Slaughter, D.; Koppel, L.; Smith, J.

    1986-02-15

    An x-ray imaging technique has been studied for the purpose of observing the current density profile in a high-current relativistic electron beam (50 MeV, 10 kA). Calculations and measurements of energy spectra and intensities are in good agreement. Results indicate sufficient photon yield for pinhole imaging when the beam deposits a small part of its energy in high-Z gas or a thin high-Z foil. Characteristic L and K x-ray emission is not found not be a reliable technique due to strong L and K shell fluorescence in the presence of intense bremsstrahlung radiation. It is also found that at pressures on the order of one atmosphere, the density of energy deposition in a gas cell is too small to generate sufficient photon yield for time-resolved measurements.

  8. Slow down of a globally neutral relativistic e-e+ beam shearing the vacuum

    NASA Astrophysics Data System (ADS)

    Alves, E. P.; Grismayer, T.; Silveirinha, M. G.; Fonseca, R. A.; Silva, L. O.

    2016-01-01

    The microphysics of relativistic collisionless shear flows is investigated in a configuration consisting of a globally neutral, relativistic {{e}-}{{e}+} beam streaming through a hollow plasma/dielectric channel. We show through multidimensional particle-in-cell simulations that this scenario excites the mushroom instability (MI), a transverse shear instability on the electron-scale, when there is no overlap (no contact) between the {{e}-}{{e}+} beam and the walls of the hollow plasma channel. The onset of the MI leads to the conversion of the beam’s kinetic energy into magnetic (and electric) field energy, effectively slowing down a globally neutral body in the absence of contact. The collisionless shear physics explored in this configuration may operate in astrophysical environments, particularly in highly relativistic and supersonic settings where macroscopic shear processes are stable.

  9. Slow down of a globally neutral relativistic e-e + beam shearing the vacuum

    NASA Astrophysics Data System (ADS)

    Alves, E. P.; Grismayer, T.; Silveirinha, M. G.; Fonseca, R. A.; Silva, L. O.

    2015-11-01

    It has been recently found that the development of electromagnetic instabilities between shearing, globally neutral polarisable dielectric slabs, separated by a nanometer-scale gap, can result in an effective non-contact friction force between slavs, which is the classical analogue of the quantum friction effect proposed by Pendry (1997). This effect has been explored analytically in the sub-relativistic regime, where the development of unstable electromagnetic modes parallel to the direction of motion are responsible for the non-contact friction effect. We explore the interaction of a relativistic, globally neutral e-e + beam streaming through a hollow plasma/dielectric in the absence of overlap (no contact). We show through analytic theory and 3D particle-in-cell simulations that this relativistic scenario excites unstable electromagnetic modes transverse to the direction of propagation. The onset of this electromagnetic instability leads to the conversion of the kinetic energy of the e-e + beam into electric and magnetic field energy, effectively slowing down a relativistic, globally neutral body in the absence of contact. We demonstrate that this effect be explored using beam properties that are readily available at the SLAC National Accelerator Laboratory.

  10. Mechanisms for generating overpressure in sedimentary basins: A reevaluation

    SciTech Connect

    Osborne, M.J.; Swarbrick, R.E.

    1997-06-01

    Overpressure can be produced by the following processes: (1) increase of compressive stress, (2) changes in the volume of the pore fluid or rock matrix, and (3) fluid movement or buoyancy. Loading during burial can generate considerable overpressure due to disequilibrium compaction, particularly during the rapid subsidence of low-permeability sediments. Horizontal stress changes can rapidly generate and dissipate large amounts of overpressure in tectonically active areas. Overpressure mechanisms involving change in volume must be well sealed to be effective. Fluid volume increases associated with aquathermal expansion and clay dehydration are too small to generate significant overpressure unless perfect sealing occurs. Hydrocarbon generation and cracking to gas could possibly produce overpressure, depending upon the kerogen type, abundance of organic matter, temperature history, and rock permeability; however, these processes may be self-limiting in a sealed system because buildup of pressure could inhibit further organic metamorphism. The potential for generating overpressure by hydrocarbon generation and cracking must be regarded as unproven at present. Fluid movement due to a hydraulic head can generate significant overpressure in shallowly buried, {open_quotes}well-plumbed{close_quotes} basins. Calculations indicate that hydrocarbon buoyancy and osmosis can generate only small amounts of localized overpressure. The upward movement of gas in an incompressible fluid also could generate significant overpressure, but requires further investigation. Stress-related mechanisms are the most likely causes of overpressure in many sedimentary basins.

  11. Visual system degeneration induced by blast overpressure.

    PubMed

    Petras, J M; Bauman, R A; Elsayed, N M

    1997-07-25

    The effect of blast overpressure on visual system pathology was studied in 14 male Sprague-Dawley rats weighing 360-432 g. Blast overpressure was simulated using a compressed-air driven shock tube, with the aim of studying a range of overpressures causing sublethal injury. Neither control (unexposed) rats nor rats exposed to 83 kiloPascals (kPa) overpressure showed evidence of visual system pathology. Neurological injury to brain visual pathways was observed in male rats surviving blast overpressure exposures of 104-110 kPa and 129-173 kPa. Optic nerve fiber degeneration was ipsilateral to the blast pressure wave. The optic chiasm contained small numbers of degenerated fibers. Optic tract fiber degeneration was present bilaterally, but was predominantly ipsilateral. Optic tract fiber degeneration was followed to nuclear groups at the level of the midbrain, midbrain-diencephalic junction, and the thalamus where degenerated fibers arborized among the neurons of: (i) the superior colliculus, (ii) pretectal region, and (iii) the lateral geniculate body. The superior colliculus contained fiber degeneration localized principally to two superficial layers (i) the stratum opticum (layer III) and (ii) stratum cinereum (layer II). The pretectal area contained degenerated fibers which were widespread in (i) the nucleus of the optic tract, (ii) olivary pretectal nucleus, (iii) anterior pretectal nucleus, and (iv) the posterior pretectal nucleus. Degenerated fibers in the lateral geniculate body were not universally distributed. They appeared to arborize among neurons of the dorsal and ventral nuclei: the ventral lateral geniculate nucleus (parvocellular and magnocellular parts); and the dorsal lateral geniculate nucleus. The axonopathy observed in the central visual pathways and nuclei of the rat brain are consistent with the presence of blast overpressure induced injury to the retina. The orbital cavities of the human skull contain frontally-directed eyeballs for binocular

  12. Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation

    SciTech Connect

    Golan, Amir; Ahmed, Musahid

    2012-01-01

    Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics.[1-4] Fundamental studies of photoionization processes of biomolecules provide information about electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water.[1, 5-9] We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-methyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline[10] located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds[1]. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations[11, 12]. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain

  13. Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation

    PubMed Central

    Golan, Amir; Ahmed, Musahid

    2012-01-01

    Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics1-4. Fundamental studies of photoionization processes of biomolecules provide information about the electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water1, 5-9. We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-dimethyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline10 located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds1. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations11, 12. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain in

  14. Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation.

    PubMed

    Golan, Amir; Ahmed, Musahid

    2012-10-30

    Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics(1-4). Fundamental studies of photoionization processes of biomolecules provide information about the electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water(1, 5-9). We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-dimethyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline(10) located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds(1). Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations(11, 12). By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn

  15. Thermal Processing of Semiconductor Materials Using Soft-Vacuum Electron Beams.

    NASA Astrophysics Data System (ADS)

    Moore, Cameron Alden

    Electron beams generated in gaseous discharges have been used to perform a variety of thermal treatments germane to semiconductor fabrication. The unique beams employed in these studies are typified by high continuous power (>100 watts per cm^2 of cathode surface), operation in relatively high pressures (0.05-25 Torr), and a wide variety of beam configurations. The ability to extract and direct high power densities lends itself to the heat treatment of silicon-based semiconductor materials. Initial studies examined the rapid thermal processing of various materials and structures using a 7.5 cm. diameter electron beam. Using this source both the annealing of ion implanted single crystal silicon and the formation of titanium disilicide were performed. The repair of damage in single-crystal silicon wafers induced by ions of boron, phosphorus, and arsenic was repaired with minimum redistribution of the dopant profile. The same apparatus was also used to form titanium silicide from both co-deposited and sequentially deposited constituent materials. While low resistivity phases of both materials were obtained, each would exhibit high resistivity behavior as well. Excessive heating of co-deposited films on silicon dioxide induces reactions between the two films, causing oxygen to be incorporated in the silicide. Ti-on-Si structures self-cleanse oxygen from the silicide during formation, in contradiction to known Si-O and Ti-O thermodynamics. A line-source (150 mm x 2 mm) electron beam was used to recrystallize silicon films deposited on oxidized silicon wafers up to 100 mm in diameter. Agglomeration of the silicon while molten was prevented via the use of (i) an encapsulating silicon dioxide film, and (ii) the introduction of appropriate wetting agents into the deposited silicon during wafer preparation. A limiting constraint to the recrystallization of full wafers was the construction of a background heater which can heat the wafer to 1200 ^circC with a uniformity of

  16. Phase equilibrium in system Ti-Si-C-B and synthesis of MAX phase layers in vacuum under the influence of electron beam

    NASA Astrophysics Data System (ADS)

    Smirnyagina, N. N.; Khaltanova, V. M.; Dasheev, D. E.; Lapina, A. E.

    2017-05-01

    Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VТ-1 are generated at diffused saturation by electron beam treatment in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

  17. Elastic properties of overpressured and unconsolidated sediments

    USGS Publications Warehouse

    Lee, Myung W.

    2003-01-01

    Differential pressure affects elastic velocities and Poisson?s ratio of sediments in such a way that velocities increase as differential pressure increases. Overpressured zones in sediments can be detected by observing an increase in Poisson?s ratio with a corresponding drop in elastic velocities. In highly overpressured sands, such as shallow water flow sands, the P-to S-wave velocity ratio (Vp/Vs) is very high, on the order of 10 or higher, due to the unconsolidated and uncemented nature of sediments. In order to predict elastic characteristics of highly overpressured sands, Biot-Gassmann theory by Lee (BGTL) is used with a variable exponent n that depends on differential pressure and the degree of consolidation/compaction. The exponent n decreases as differential pressure and the degree of consolidation increases, and, as n decreases, velocity increases and Vp/Vs decreases. The predicted velocity ratio by BGTL agrees well with the measured velocity ratio at low differential pressure for unconsolidated sediments.

  18. Coasting after overpressure induction with sevoflurane.

    PubMed

    Hendrickx, J F; Vandeput, D M; De Geyndt, A M; DeLoof, T; De Wolf, A M

    2000-03-01

    To evaluate the clinical feasibility of using a coasting technique to temporarily maintain anesthesia after overpressure induction with sevoflurane. Prospective clinical study. Large teaching hospital. 12 ASA physical status I, II, and III patients receiving general anesthesia for a variety of peripheral procedures. After overpressure induction of anesthesia with sevoflurane (8%) in an O(2)/N(2)O mixture, the fresh gas flow (FGF) was lowered to 0.5 L/min and the vaporizer was turned off (coasting). After priming a circle system with sevoflurane (8% sevoflurane vaporizer setting in 6 L/min O(2)/N(2)O [33%/66%] for 30 s), patients took several vital capacity breaths from the mixture until loss of consciousness. After 3.4 +/- 0.7 min, depth of anesthesia was considered adequate for laryngeal mask airway (LMA) insertion, and FGF was reduced to 0.5 L/min (33% O(2), 66% N(2)O) and the sevoflurane vaporizer was turned off. The end-expired sevoflurane concentration (Et(sevo)) decreased from 5.8 +/- 1.3% just before insertion of the LMA to 0.97 +/- 0.22% at 20 minutes. After overpressure induction with sevoflurane, coasting during minimal flow anesthesia (FGF 0.5 L/min) is a simple technique that can maintain anesthesia for short procedures (less than 15 to 20 min), or can be used as a bridge or an adjunct to other low-flow techniques.

  19. Simulation Assisted Risk Assessment: Blast Overpressure Modeling

    NASA Technical Reports Server (NTRS)

    Lawrence, Scott L.; Gee, Ken; Mathias, Donovan; Olsen, Michael

    2006-01-01

    A probabilistic risk assessment (PRA) approach has been developed and applied to the risk analysis of capsule abort during ascent. The PRA is used to assist in the identification of modeling and simulation applications that can significantly impact the understanding of crew risk during this potentially dangerous maneuver. The PRA approach is also being used to identify the appropriate level of fidelity for the modeling of those critical failure modes. The Apollo launch escape system (LES) was chosen as a test problem for application of this approach. Failure modes that have been modeled and/or simulated to date include explosive overpressure-based failure, explosive fragment-based failure, land landing failures (range limits exceeded either near launch or Mode III trajectories ending on the African continent), capsule-booster re-contact during separation, and failure due to plume-induced instability. These failure modes have been investigated using analysis tools in a variety of technical disciplines at various levels of fidelity. The current paper focuses on the development and application of a blast overpressure model for the prediction of structural failure due to overpressure, including the application of high-fidelity analysis to predict near-field and headwinds effects.

  20. Deuterium Neutral Beam Orbits In NSTX-U Nonaxisymmetric Vacuum Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Philion, Jonah; Darrow, Douglass

    2016-10-01

    Axisymmetry of the tokamak magnetic field provides good fast ion radial confinement. Perturbations from this symmetry could induce fast ion radial diffusion and loss. A nonaxisymmetric perturbation was chosen to model the effect of this symmetry loss on NSTX-U deuterium neutral beam ions. Passing and banana orbits in the perturbed field were simulated by integrating the Lorentz force over a duration shorter than the collision time of ions. Upon comparison with analogous orbits in the unperturbed field, the perturbation is shown to have a dispersive effect on the magnetic moment of particle orbit guiding centers. In particular, banana orbits acquire oscillating magnetic moments when subject to the nonaxisymmetric field. The behavior is modeled as a diffusion coefficient which varies with the magnetic moment and canonical angular momentum of the orbit.

  1. On the role of secondary electrons in beam plasma generation inside a dielectric flask by fore-vacuum plasma-cathode electron source

    NASA Astrophysics Data System (ADS)

    Zolotukhin, D. B.; Burdovitsin, V. A.; Oks, E. M.

    2017-09-01

    The paper presents the results of experimental research and numerical simulation, demonstrating a considerable influence of secondary electrons on parameters of the beam-produced plasma generated at a pressure range of 1-13 Pa by injection of a continuous (with current of tens mA) electron beam into a dielectric (quartz) flask. An electron beam was formed by a fore-vacuum plasma-cathode electron source based on a hollow cathode discharge. The secondary electrons were emitted as a result of high-energy (3-8 keV) electron beam bombardment mainly a bottom end of the flask. These electrons provide an additional contribution to the ionization of the gas and also affect on the longitudinal distribution of the plasma density along the flask.

  2. Nanograting-based compact vacuum ultraviolet spectrometer and beam profiler for in situ characterization of high-order harmonic generation light sources.

    PubMed

    Kornilov, Oleg; Wilcox, Russell; Gessner, Oliver

    2010-06-01

    A compact, versatile device for vacuum ultraviolet (VUV) beam characterization is presented. It combines the functionalities of a VUV spectrometer and a VUV beam profiler in one unit and is entirely supported by a standard DN200 CF flange. The spectrometer employs a silicon nitride transmission nanograting in combination with a microchannel plate-based imaging detector. This enables the simultaneous recording of wavelengths ranging from 10 to 80 nm with a resolution of 0.25-0.13 nm. Spatial beam profiles with diameters up to 10 mm are imaged with 0.1 mm resolution. The setup is equipped with an in-vacuum translation stage that allows for in situ switching between the spectrometer and beam profiler modes and for moving the setup out of the beam. The simple, robust design of the device is well suited for nonintrusive routine characterization of emerging laboratory- and accelerator-based VUV light sources. Operation of the device is demonstrated by characterizing the output of a femtosecond high-order harmonic generation light source.

  3. Micro-/nanosized cantilever beams and mass sensors under applied axial tensile/compressive force vibrating in vacuum and viscous fluid

    SciTech Connect

    Stachiv, Ivo; Fang, Te-Hua; Chen, Tao-Hsing

    2015-11-15

    Vibrating micro-/nanosized cantilever beams under an applied axial force are the key components of various devices used in nanotechnology. In this study, we perform a complete theoretical investigation of the cantilever beams under an arbitrary value of the axial force vibrating in a specific environment such as vacuum, air or viscous fluid. Based on the results easy accessible expressions enabling one the fast and highly accurate estimations of changes in the Q-factor and resonant frequencies of beam oscillating in viscous fluid caused by the applied axial force are derived and analyzed. It has been also shown that for beam-to-string and string vibrational regimes the mode shape starts to significantly deviate from the one known for a beam without axial force. Moreover, a linear dependency of the vibrational amplitude in resonance on the dimensionless tension parameter has been found. We revealed that only a large axial force, i.e. the string vibrational regime, significantly improves the Q-factor of beams submerged in fluid, while an increase of the axial force in beam and beam-to-string transition regimes has a negligibly small impact on the Q-factor enhancement. Experiments carried out on the carbon nanotubes and nanowires are in a good agreement with present theoretical predictions.

  4. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, William A.

    1994-01-01

    A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife.

  5. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, W.A.

    1994-02-08

    A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife. 6 figures.

  6. The pathology of primary blast overpressure injury.

    PubMed

    Mayorga, M A

    1997-07-25

    Primary blast injury occurs in civilian and military detonations and from the firing of weapon systems. The pathology of primary blast injury has been reported for the last 70 years and has primarily been limited to descriptions of gross pathology and histology. Commonly accepted tenets have not been confirmed as blast overpressure experiments in enclosures and with multiple detonations have been conducted. Organ systems other than the ear and the lung are playing a greater role in injury definition and research importance. This paper is an overview and update of the current understanding of the pathology of primary blast injury.

  7. 46 CFR 153.365 - Liquid overpressurization protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.365 Liquid overpressurization protection. (a) Except as noted...

  8. 46 CFR 153.365 - Liquid overpressurization protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.365 Liquid overpressurization protection. (a) Except as noted...

  9. 46 CFR 153.365 - Liquid overpressurization protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.365 Liquid overpressurization protection. (a) Except as noted...

  10. 46 CFR 153.365 - Liquid overpressurization protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.365 Liquid overpressurization protection. (a) Except as noted...

  11. 46 CFR 153.365 - Liquid overpressurization protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Liquid overpressurization protection. 153.365 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.365 Liquid overpressurization protection. (a) Except as noted...

  12. 49 CFR 192.195 - Protection against accidental overpressuring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Protection against accidental overpressuring. 192.195 Section 192.195 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE... Pipeline Components § 192.195 Protection against accidental overpressuring. (a) General requirements...

  13. K-130 Cyclotron vacuum system

    NASA Astrophysics Data System (ADS)

    Yadav, R. C.; Bhattacharya, S.; Bhole, R. B.; Roy, Anindya; Pal, Sarbajit; Mallik, C.; Bhandari, R. K.

    2012-11-01

    The vacuum system for K-130 cyclotron has been operational since 1977. It consists of two sub-systems, main vacuum system and beam line vacuum system. The main vacuum system is designed to achieve and maintain vacuum of about 1 × 10-6 mbar inside the 23 m3 volume of acceleration chamber comprising the Resonator tank and the Dee tank. The beam line vacuum system is required for transporting the extracted beam with minimum loss. These vacuum systems consist of diffusion pumps backed by mechanical pumps like roots and rotary pumps. The large vacuum pumps and valves of the cyclotron vacuum system were operational for more than twenty five years. In recent times, problems of frequent failures and maintenance were occurring due to aging and lack of appropriate spares. Hence, modernisation of the vacuum systems was taken up in order to ensure a stable high voltage for radio frequency system and the extraction system. This is required for efficient acceleration and transportation of high intensity ion beam. The vacuum systems have been upgraded by replacing several pumps, valves, gauges and freon units. The relay based control system for main vacuum system has also been replaced by PLC based state of the art control system. The upgraded control system enables inclusion of additional operational logics and safety interlocks into the system. The paper presents the details of the vacuum system and describes the modifications carried out for improving the performance and reliability of the vacuum system.

  14. Influence of 700 °C vacuum annealing on fracture behavior of micro/nanoscale focused ion beam fabricated silicon structures

    NASA Astrophysics Data System (ADS)

    Goshima, Yoshiharu; Fujii, Tatsuya; Inoue, Shozo; Namazu, Takahiro

    2016-06-01

    In this paper, we describe the influence of 700 °C vacuum annealing on strength and fracture behavior of micro- and nano-scale Si structures fabricated by focused ion beam (FIB). Si nanowires (NWs) made from silicon-on-nothing (SON) membrane are fabricated using FIB. Microscale Si specimens are fabricated by conventional micromachining technologies and FIB. These specimens are tensioned to failure using specially developed microelectromechanical systems (MEMS) device and thin-film tensile tester, respectively. The mean fracture strengths of the nano- and microscale specimens are 5.6 and 1.6 GPa, respectively, which decrease to 2.9 and 0.9 GPa after vacuum annealing at 700 °C for only 10 s. These strength values do not vary with increasing annealing time. Fracture origin and its behavior are discussed in the light of fracture surface and FIB damage layer observations.

  15. Propulsion system ignition overpressure for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Ryan, R. S.; Jones, J. H.; Guest, S. H.; Struck, H. G.; Rheinfurth, M. H.; Verferaime, V. S.

    1981-01-01

    Liquid and solid rocket motor propulsion systems create an overpressure wave during ignition, caused by the accelerating gas particles pushing against or displacing the air contained in the launch pad or launch facility and by the afterburning of the fuel-rich gases. This wave behaves as a blast or shock wave characterized by a positive triangular-shaped first pulse and a negative half-sine wave second pulse. The pulse travels up the space vehicle and has the potential of either overloading individual elements or exciting overall vehicle dynamics. The latter effect results from the phasing difference of the wave from one side of the vehicle to the other. This overpressure phasing, or delta P environment, because of its frequency content as well as amplitude, becomes a design driver for certain panels (e.g., thermal shields) and payloads for the Space Shuttle. The history of overpressure effects on the Space Shuttle, the basic overpressure phenomenon, Space Shuttle overpressure environment, scale model overpressure testing, and techniques for suppressing the overpressure environments are considered.

  16. Ignition overpressure study from solid rocket motor firings

    NASA Technical Reports Server (NTRS)

    Counter, Douglas D.

    1987-01-01

    The objective was to investigate, through experimental means, the basic mechanisms influencing ignition overpressure and to determine ways to suppress ignition overpressure. Ignition overpressure was studied using solid rocket motors with geometry scaled at 1 percent of the Shuttle's Solid Rocket Boosters. Both water injection and aerosol foam were examined as a mean of reducing ignition overpressure. The results of the water injection tests indicate that a relatively small amount of water is sufficient to provide significant suppression. Of the flow rates tested, the lower water injection flow rates provided the best reduction of the ignition overpressure wave. Also, the test results show there is an optimum water flow rate range that provides the best suppression, and as this range is exceeded the effectiveness of water to reduce ignition overpressure is decreased. Aerosol foam provided very little reduction of ignition overpressure, but only small volumes of foam were used and further testing is necessary to determine its total effectiveness as a means of suppression.

  17. Record of source-generated overpressures, Venezuela

    SciTech Connect

    Vrolijk, P.J.; Pottorf, R.J.; Maze, W.B. )

    1996-01-01

    Fluid pressures affect migration of oil, gas, and water in continental margins. Burial and thermal history models describe the degree to which indercompaction or thermal expansion of fluids contribute to fluid pressure histories, but it is more difficult to evaluate how source-terms, such as oil yield or mineral dehydration reactions, impact paleo-fluid pressures. In this study, we document how a thick, maturing source rock helped create near-lithostatic fluid pressures that generated overpressures in reservoir rocks. We analyzed abundant oil-filled and rare aqueous fluid inclusions in calcite-filled fractures in the La Luna Fm. source rock and in the underlying Cogollo Gp. carbonate reservoir in the W. Maracaibo Basin, Venezuela. Homogenization temperatures (Th) of oil-filled inclusions range from 25-42[degrees]C in the La Luna Fm. and from 25-105[degrees]C in the Cogollo Gp., and associated gravities (determined from fluorescence properties) range from 28-43[degrees]API and 17-45[degrees]API, respectively. Integration of Th with the burial and thermal history of the sampled horizons leads to the conclusion that fractures in the La Luna Fm. formed under near-lithostatic fluid pressure conditions in the presence of a gas-charged oil. The values from fractures in the Cogollo Gp. are higher than in the La Luna Fm and become more variable with increasing depth below La Luna. We interpret those fractures to have formed under lower fluid pressure conditions and/or with a less gas-charged oil than for La Luna. This interpretation of the distribution of paleo-fluid pressures is supported by the observation of modern inverted fluid pressure gradients between upper and lower Cogollo Gp. reservoirs. Thus late expulsion of a gas-charged oil created near-lithostatic fluid pressures in the La Luna Fm. source rock, and those fluid pressures bled downward through fractures into the adjoining reservoir rocks, contributing to the overpressures we observe today.

  18. Record of source-generated overpressures, Venezuela

    SciTech Connect

    Vrolijk, P.J.; Pottorf, R.J.; Maze, W.B.

    1996-12-31

    Fluid pressures affect migration of oil, gas, and water in continental margins. Burial and thermal history models describe the degree to which indercompaction or thermal expansion of fluids contribute to fluid pressure histories, but it is more difficult to evaluate how source-terms, such as oil yield or mineral dehydration reactions, impact paleo-fluid pressures. In this study, we document how a thick, maturing source rock helped create near-lithostatic fluid pressures that generated overpressures in reservoir rocks. We analyzed abundant oil-filled and rare aqueous fluid inclusions in calcite-filled fractures in the La Luna Fm. source rock and in the underlying Cogollo Gp. carbonate reservoir in the W. Maracaibo Basin, Venezuela. Homogenization temperatures (Th) of oil-filled inclusions range from 25-42{degrees}C in the La Luna Fm. and from 25-105{degrees}C in the Cogollo Gp., and associated gravities (determined from fluorescence properties) range from 28-43{degrees}API and 17-45{degrees}API, respectively. Integration of Th with the burial and thermal history of the sampled horizons leads to the conclusion that fractures in the La Luna Fm. formed under near-lithostatic fluid pressure conditions in the presence of a gas-charged oil. The values from fractures in the Cogollo Gp. are higher than in the La Luna Fm and become more variable with increasing depth below La Luna. We interpret those fractures to have formed under lower fluid pressure conditions and/or with a less gas-charged oil than for La Luna. This interpretation of the distribution of paleo-fluid pressures is supported by the observation of modern inverted fluid pressure gradients between upper and lower Cogollo Gp. reservoirs. Thus late expulsion of a gas-charged oil created near-lithostatic fluid pressures in the La Luna Fm. source rock, and those fluid pressures bled downward through fractures into the adjoining reservoir rocks, contributing to the overpressures we observe today.

  19. Over-Pressurized Drums: Their Causes and Mitigation

    SciTech Connect

    Simmons, Fred; Kuntamukkula, Murty; Quigley, David; Robertson, Janeen; Freshwater, David

    2009-07-10

    Having to contend with bulging or over-pressurized drums is, unfortunately, a common event for people storing chemicals and chemical wastes. (Figure 1) The Department of Energy alone reported over 120 incidents of bulging drums between 1992 and 1999 (1). Bulging drums can be caused by many different mechanisms, represent a number of significant hazards and can be tricky to mitigate. In this article, we will discuss reasons or mechanisms by which drums can become over-pressurized, recognition of the hazards associated with and mitigation of over-pressurized drums, and methods that can be used to prevent drum over-pressurization from ever occurring. Drum pressurization can represent a significant safety hazard. Unless recognized and properly mitigated, improperly manipulated pressurized drums can result in employee exposure, employee injury, and environmental contamination. Therefore, recognition of when a drum is pressurized and knowledge of pressurized drum mitigation techniques is essential.

  20. Modular ultrahigh vacuum-compatible gas-injection system with an adjustable gas flow for focused particle beam-induced deposition

    SciTech Connect

    Klingenberger, D.; Huth, M.

    2009-09-15

    A gas-injection system (GIS) heats up a powdery substance and transports the resulting gas through a capillary into a vacuum chamber. Such a system can be used to guide a (metal)organic precursor gas very close to the focal area of an electron or ion beam, where a permanent deposit is created and adheres to the substrate. This process is known as focused particle beam-induced deposition. The authors present design principles and give construction details of a GIS suitable for ultrahigh vacuum usage. The GIS is composed of several self-contained components which can be customized rather independently. It allows for a continuously adjustable gas-flow rate. The GIS was attached to a standard scanning electron microscope (JEOL 6100) and tested with the tungsten precursor W(CO){sub 6}. The analysis of the deposits by means of atomic force microscopy and energy dispersive x-ray spectroscopy provides clear evidence that excellent gas-flow-rate stability and ensuing growth rate and metal-content reproducibility are experienced.

  1. Elastic-plastic response charts for nuclear overpressures. Final report

    SciTech Connect

    Guice, L.K.; Kiger, S.A.

    1984-06-01

    The single-degree-of-freedom equation of motion for an elastic-plastic system with forcing functions that are representative of nuclear weapon simulations is nondimensionalized and solved. Numerical solutions are calculated by the Newmark Beta method, and response charts incorporating nondimensionalized structural and loading parameters for the Speicher-Brode nuclear pressure history description are provided. A computer code is presented for solving the elastic-plastic problem for Speicher-Brode overpressure as well as triangular-shaped overpressures.

  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. Effusive molecular beam-sampled Knudsen flow reactor coupled to vacuum ultraviolet single photon ionization mass spectrometry using an external free radical source

    SciTech Connect

    Leplat, N.; Rossi, M. J.

    2013-11-15

    A new apparatus using vacuum ultraviolet single photon ionization mass spectrometry (VUV SPIMS) of an effusive molecular beam emanating from a Knudsen flow reactor is described. It was designed to study free radical-molecule kinetics over a significant temperature range (300–630 K). Its salient features are: (1) external free radical source, (2) counterpropagating molecular beam and diffuse VUV photon beam meeting in a crossed-beam ion source of a quadrupole mass spectrometer with perpendicular ion extraction, (3) analog detection of the photocurrent of the free radical molecular cation, and (4) possibility of detecting both free radicals and closed shell species in the same apparatus and under identical reaction conditions owing to the presence of photoelectrons generated by the photoelectric effect of the used VUV-photons. The measured thermal molecular beam-to-background ratio was 6.35 ± 0.39 for Ar and 10.86 ± 1.59 for i-C{sub 4}H{sub 10} at 300 K, a factor of 2.52 and 1.50 smaller, respectively, than predicted from basic gas-dynamic considerations. Operating parameters as well as the performance of key elements of the instrument are presented and discussed. Coupled to an external free radical source a steady-state specific exit flow of 1.6 × 10{sup 11} and 5.0 × 10{sup 11} molecule s{sup −1} cm{sup −3} of C{sub 2}H{sub 5}{sup •} (ethyl) and t-C{sub 4}H{sub 9}{sup •} (t-butyl) free radicals have been detected using VUV SPIMS at their molecular ion m/z 29 and 57, respectively, at 300 K.

  4. Effusive molecular beam-sampled Knudsen flow reactor coupled to vacuum ultraviolet single photon ionization mass spectrometry using an external free radical source.

    PubMed

    Leplat, N; Rossi, M J

    2013-11-01

    A new apparatus using vacuum ultraviolet single photon ionization mass spectrometry (VUV SPIMS) of an effusive molecular beam emanating from a Knudsen flow reactor is described. It was designed to study free radical-molecule kinetics over a significant temperature range (300-630 K). Its salient features are: (1) external free radical source, (2) counterpropagating molecular beam and diffuse VUV photon beam meeting in a crossed-beam ion source of a quadrupole mass spectrometer with perpendicular ion extraction, (3) analog detection of the photocurrent of the free radical molecular cation, and (4) possibility of detecting both free radicals and closed shell species in the same apparatus and under identical reaction conditions owing to the presence of photoelectrons generated by the photoelectric effect of the used VUV-photons. The measured thermal molecular beam-to-background ratio was 6.35 ± 0.39 for Ar and 10.86 ± 1.59 for i-C4H10 at 300 K, a factor of 2.52 and 1.50 smaller, respectively, than predicted from basic gas-dynamic considerations. Operating parameters as well as the performance of key elements of the instrument are presented and discussed. Coupled to an external free radical source a steady-state specific exit flow of 1.6 × 10(11) and 5.0 × 10(11) molecule s(-1) cm(-3) of C2H5(●) (ethyl) and t-C4H9(●) (t-butyl) free radicals have been detected using VUV SPIMS at their molecular ion m/z 29 and 57, respectively, at 300 K.

  5. Overpressure and seals in the North Sea - a model approach

    SciTech Connect

    Cavanagh, A.G.; Couples, D.D.; Haszeldine, R.S.

    1996-12-31

    Overpressure prediction in the North Sea is complicated by fault seal assumptions. The computer code, BasinMod-2D, is used to simulate overpressure for a small-scale case study, the Puffin structure, located on the western flank of the Central Graben. This area is characterized by tilted fault blocks and syn-rift sedimentation of Upper Jurassic Fulmar sandstones with a post-rift cover of Cretaceous chalk and Tertiary mudstones. The model, a 10 km W-E section based on published seismic data, is tied to detailed well stratigraphy in 29/10 -2 with pressure data from RFT and mudweight. The model fails to replicate observed overpressure data. The simulated overpressure is 20 MPa lower than the measured pressure of 85 MPa in the Puffin structure. The model fails to simulate hydrocarbon accumulation in the Fulmar sandstone reservoir, in contradiction to the observed bitumen indication of paleoaccumulation. The model also raises important questions as to the validity of uncalibrated parameter manipulation as a means of forward modelling fault seal, with specific reference to shale permeability. We contend that these failures are not due to model limitations, but are the result of the size-scale of this case study. The inference is that overpressure and hydrocarbon creation and transmission is on a size scale fault seal at one time can leak hydrocarbons at another time. We consider that the drive for this comes from pressure increase during hydrocarbon generation in the deep kitchen.

  6. Overpressure and seals in the North Sea - a model approach

    SciTech Connect

    Cavanagh, A.G.; Couples, D.D.; Haszeldine, R.S. )

    1996-01-01

    Overpressure prediction in the North Sea is complicated by fault seal assumptions. The computer code, BasinMod-2D, is used to simulate overpressure for a small-scale case study, the Puffin structure, located on the western flank of the Central Graben. This area is characterized by tilted fault blocks and syn-rift sedimentation of Upper Jurassic Fulmar sandstones with a post-rift cover of Cretaceous chalk and Tertiary mudstones. The model, a 10 km W-E section based on published seismic data, is tied to detailed well stratigraphy in 29/10 -2 with pressure data from RFT and mudweight. The model fails to replicate observed overpressure data. The simulated overpressure is 20 MPa lower than the measured pressure of 85 MPa in the Puffin structure. The model fails to simulate hydrocarbon accumulation in the Fulmar sandstone reservoir, in contradiction to the observed bitumen indication of paleoaccumulation. The model also raises important questions as to the validity of uncalibrated parameter manipulation as a means of forward modelling fault seal, with specific reference to shale permeability. We contend that these failures are not due to model limitations, but are the result of the size-scale of this case study. The inference is that overpressure and hydrocarbon creation and transmission is on a size scale fault seal at one time can leak hydrocarbons at another time. We consider that the drive for this comes from pressure increase during hydrocarbon generation in the deep kitchen.

  7. A new cluster-ion-beam source for secondary ion mass spectrometry (SIMS) using the electrospray of a pure ionic liquid under high vacuum

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yukio; Saito, Naoaki; Nonaka, Hidehiko; Nakanaga, Taisuke; Ichimura, Shingo

    2010-06-01

    Electrospray characteristics were studied using a pure room-temperature molten salt (i.e., an ionic liquid) at pressures around 10 -5 Pa as well as at atmospheric pressure. The ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide was tested, which has negligible vapor pressure and high conductivity. During electrospray, the ionic liquid was introduced at a constant flow rate into a stainless-steel capillary (i.d. 30 μm). It was demonstrated that stable electrosprayed currents exceeding ±1 μΑ were continuously produced in both positive and negative modes. The electrosprayed currents in a high vacuum were twice those at atmospheric pressure. It was found that gas pressure rose slightly with increasing electrosprayed currents. Residual gas analysis revealed that gas component at negative mode was different from that at positive mode. Experimental results indicate that vacuum electrospray of pure ionic liquids is applicable to a massive-cluster beam source for SIMS.

  8. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system

    NASA Astrophysics Data System (ADS)

    Rutkowski, M. M.; McNicholas, K. M.; Zeng, Zhaoquan; Brillson, L. J.

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (˜1 eV) in the core level binding energies was observed.

  9. Design of an ultrahigh vacuum transfer mechanism to interconnect an oxide molecular beam epitaxy growth chamber and an x-ray photoemission spectroscopy analysis system.

    PubMed

    Rutkowski, M M; McNicholas, K M; Zeng, Zhaoquan; Brillson, L J

    2013-06-01

    We designed a mechanism and the accompanying sample holders to transfer between a VEECO 930 oxide molecular beam epitaxy (MBE) and a PHI Versa Probe X-ray photoemission spectroscopy (XPS) chamber within a multiple station growth, processing, and analysis system through ultrahigh vacuum (UHV). The mechanism consists of four parts: (1) a platen compatible with the MBE growth stage, (2) a platen compatible with the XPS analysis stage, (3) a sample coupon that is transferred between the two platens, and (4) the accompanying UHV transfer line. The mechanism offers a robust design that enables transfer back and forth between the growth chamber and the analysis chamber, and yet is flexible enough to allow transfer between standard sample holders for thin film growth and masked sample holders for making electrical contacts and Schottky junctions, all without breaking vacuum. We used this mechanism to transfer a barium strontium titanate thin film into the XPS analysis chamber and performed XPS measurements before and after exposing the sample to the air. After air exposure, a thin overlayer of carbon was found to form and a significant shift (~1 eV) in the core level binding energies was observed.

  10. Probability analysis of MCO over-pressurization during staging

    SciTech Connect

    Pajunen, A.L.

    1997-06-05

    The purpose of this calculation is to determine the probability of Multi-Canister Overpacks (MCOs) over-pressurizing during staging at the Canister Storage Building (CSB). Pressurization of an MCO during staging is dependent upon changes to the MCO gas temperature and the build-up of reaction products during the staging period. These effects are predominantly limited by the amount of water that remains in the MCO following cold vacuum drying that is available for reaction during staging conditions. Because of the potential for increased pressure within an MCO, provisions for a filtered pressure relief valve and rupture disk have been incorporated into the MCO design. This calculation provides an estimate of the frequency that an MCO will contain enough water to pressurize beyond the limits of these design features. The results of this calculation will be used in support of further safety analyses and operational planning efforts. Under the bounding steady state CSB condition assumed for this analysis, an MCO must contain less than 1.6 kg (3.7 lbm) of water available for reaction to preclude actuation of the pressure relief valve at 100 psid. To preclude actuation of the MCO rupture disk at 150 psid, an MCO must contain less than 2.5 kg (5.5 lbm) of water available for reaction. These limits are based on the assumption that hydrogen generated by uranium-water reactions is the sole source of gas produced within the MCO and that hydrates in fuel particulate are the primary source of water available for reactions during staging conditions. The results of this analysis conclude that the probability of the hydrate water content of an MCO exceeding 1.6 kg is 0.08 and the probability that it will exceed 2.5 kg is 0.01. This implies that approximately 32 of 400 staged MCOs may experience pressurization to the point where the pressure relief valve actuates. In the event that an MCO pressure relief valve fails to open, the probability is 1 in 100 that the MCO would experience

  11. The use of loop-seals for the control of the overpressures in hydraulic transients evolving in a sea service water system

    NASA Astrophysics Data System (ADS)

    Canetta, D.; Capozza, A.; Iovino, G.

    The transient response following pump trip-offs and start-ups was investigated in the sea water system of a nuclear power plant. Specific care was devoted to water column separation and cavity collapse phenomena. A computer program designed for analysis of complex hydraulic networks was used. It is found that dangerous overpressures can be avoided by the use of loop seals. The design of the vacuum breaker valves of the loop seals and the optimization of overall transient behavior is discussed.

  12. Overpressure proof testing of large infrared windows for aircraft applications

    NASA Astrophysics Data System (ADS)

    Pruszynski, Charles J.

    1991-10-01

    Many commonly used infrared window materials, such as zinc sulfide and zinc selenide, are subject to structural failure due to stress-corrosion induced cracking. This failure mechanism is of critical importance in applications in which the window experiences high static pressure loading for prolonged periods in humid atmospheres, conditions typical of airborne optical windows. The most effective means of screening windows against failure due to this mechanism is by use of overpressure proof testing. In this paper, the design of overpressure proof tests for large airborne infrared windows is discussed. The underlying physical phenomena and governing mathematical relationships are presented. A hypothetical proof test design for a large infrared window to be employed in a man-rated aircraft is developed to illustrate the application of the analytical methodology. Practical considerations in the execution of large infrared window overpressure proof tests are also discussed.

  13. Ares I Scale Model Acoustic Test Overpressure Results

    NASA Technical Reports Server (NTRS)

    Casiano, M. J.; Alvord, D. A.; McDaniels, D. M.

    2011-01-01

    A summary of the overpressure environment from the 5% Ares I Scale Model Acoustic Test (ASMAT) and the implications to the full-scale Ares I are presented in this Technical Memorandum. These include the scaled environment that would be used for assessing the full-scale Ares I configuration, observations, and team recommendations. The ignition transient is first characterized and described, the overpressure suppression system configuration is then examined, and the final environment characteristics are detailed. The recommendation for Ares I is to keep the space shuttle heritage ignition overpressure (IOP) suppression system (below-deck IOP water in the launch mount and mobile launcher and also the crest water on the main flame deflector) and the water bags.

  14. Effects of Filtering on Experimental Blast Overpressure Measurements.

    PubMed

    Alphonse, Vanessa D; Kemper, Andrew R; Duma, Stefan M

    2015-01-01

    When access to live-fire test facilities is limited, experimental studies of blast-related injuries necessitate the use of a shock tube or Advanced Blast Simulator (ABS) to mimic free-field blast overpressure. However, modeling blast overpressure in a laboratory setting potentially introduces experimental artifacts in measured responses. Due to the high sampling rates required to capture a blast overpressure event, proximity to alternating current (AC-powered electronics) and poorly strain-relieved or unshielded wires can result in artifacts in the recorded overpressure trace. Data in this study were collected for tests conducted on an empty ABS (“Empty Tube”) using high frequency pressure sensors specifically designed for blast loading rates (n=5). Additionally, intraocular overpressure data (“IOP”) were collected for porcine eyes potted inside synthetic orbits located inside the ABS using an unshielded miniature pressure sensor (n=3). All tests were conducted at a 30 psi static overpressure level. A 4th order phaseless low pass Butterworth software filter was applied to the data. Various cutoff frequencies were examined to determine if the raw shock wave parameters values could be preserved while eliminating noise and artifacts. A Fast Fourier Transform (FFT) was applied to each test to examine the frequency spectra of the raw and filtered signals. Shock wave parameters (time of arrival, peak overpressure, positive duration, and positive impulse) were quantified using a custom MATLAB® script. Lower cutoff frequencies attenuated the raw signal, effectively decreasing the peak overpressure and increasing the positive duration. Rise time was not preserved the filtered data. A CFC 6000 filter preserved the remaining shock wave parameters within ±2.5% of the average raw values for the Empty Tube test data. A CFC 7000 filter removed experimental high-frequency artifacts and preserved the remaining shock wave parameters within ±2.5% of the average raw values for

  15. Multimode quantum properties of a self-imaging optical parametric oscillator: Squeezed vacuum and Einstein-Podolsky-Rosen-beams generation

    SciTech Connect

    Lopez, L.; Chalopin, B.; Riviere de la Souchere, A.; Fabre, C.; Treps, N.; Maitre, A.

    2009-10-15

    We investigate the spatial quantum properties of the light emitted by a perfectly spatially degenerate optical parametric oscillator (self-imaging optical parametric oscillator). We show that this device produces local squeezing for areas bigger than a coherence area that depends on the crystal length and pump width. Furthermore, it generates local EPR beams in the far field. We show, calculating the eigenmodes of the system, that it is highly multimode for realistic experimental parameters.

  16. Fluid overpressures and strength of the sedimentary upper crust

    NASA Astrophysics Data System (ADS)

    Suppe, John

    2014-12-01

    The classic crustal strength-depth profile based on rock mechanics predicts a brittle strength σ1 -σ3 = κ(ρbar gz -Pf) that increases linearly with depth as a consequence of [1] the intrinsic brittle pressure dependence κ plus [2] an assumption of hydrostatic pore-fluid pressure, Pf = ρwgz. Many deep borehole stress data agree with a critical state of failure of this form. In contrast, fluid pressures greater than hydrostatic ρbar gz >Pf >ρw gz are normally observed in clastic continental margins and shale-rich mountain belts. Therefore we explore the predicted shapes of strength-depth profiles using data from overpressured regions, especially those dominated by the widespread disequilibrium-compaction mechanism, in which fluid pressures are hydrostatic above the fluid-retention depth zFRD and overpressured below, increasing parallel to the lithostatic gradient ρbar gz . Both brittle crustal strength and frictional fault strength below the zFRD must be constant with depth because effective stress (ρbar gz -Pf) is constant, in contrast with the classic linearly increasing profile. Borehole stress and fluid-pressure measurements in several overpressured deforming continental margins agree with this constant-strength prediction, with the same pressure-dependence κ as the overlying hydrostatic strata. The role of zFRD in critical-taper wedge mechanics and jointing is illustrated. The constant-strength approximation is more appropriate for overpressured crust than classic linearly increasing models.

  17. Rocket Launch-Induced Vibration and Ignition Overpressure Response

    NASA Technical Reports Server (NTRS)

    Caimi, Raoul; Margasahayam, Ravi; Nayfeh, Jamal; Thompson, Karen (Technical Monitor)

    2001-01-01

    Rocket-induced vibration and ignition overpressure response environments are predicted in the low-frequency (5 to 200 hertz) range. The predictions are necessary to evaluate their impact on critical components, structures, and facilities in the immediate vicinity of the rocket launch pad.

  18. Rocket Launch-Induced Vibration and Ignition Overpressure Response

    NASA Technical Reports Server (NTRS)

    Caimi, Raoul E.; Margashayam, Ravi N.; Nayfeh, Jamal F.; Thompson, Karen (Technical Monitor)

    2001-01-01

    Rocket-induced vibration and ignition overpressure response environments are predicted in the low-frequency (5 to 200 hertz) range. The predictions are necessary to evaluate their impact on critical components, structures, and facilities in the immediate vicinity of the rocket launch pad.

  19. Thin-window high-efficiency position sensitive proportional counter for the vacuum flat crystal spectrometers on the Lawrence Livermore National Laboratory electron beam ion trap (abstract)

    SciTech Connect

    Brown, G. V.; Beiersdorfer, P.; Goddard, R.; Wargelin, B.; Utter, S. B.

    2001-01-01

    We have mounted 1 {mu}m thick aluminized polyimide windows onto the position sensitive proportional counters employed by the wide-band flat crystal spectrometers at the Lawrence Livermore National Laboratory electron beam ion trap experiment. The aluminized polyimide, supported by thin wires across the short axis of the window, is used to isolate the detection chamber of the proportional counters, which operate at a pressure of 760 Torr, from the vacuum chamber of the spectrometer. The windows are modified versions of those developed for the proportional counters which were used during ground calibration of the Chandra X-ray Observatory. The transmission properties of these windows are, therefore, well known. The increased transmission efficiency of the polyimide windows relative to the 4 {mu}m thick polypropylene window material previously employed by our proportional counters has extended the useful range of the spectrometer from roughly 20 to 30 Aa at energies below the carbon edge, as well as increasing detection efficiency at wavelengths beyond the carbon edge. Using an octadecyl hydrogen maleate crystal with 2d=63.5Aa, we demonstrate the increased wavelength coverage by measuring the resonance, intercombination, and forbidden lines in helium-like NVII in two different density regimes. The thin polyimide windows have also increased the efficiency of the spectrometers entire wavelength range. To demonstrate the increased efficiency we compare the FeXVII spectrum in the 15--17 Aa band measured with the 1 {mu}m aluminized polyimide windows to the 4 {mu}m aluminized polypropylene windows. The comparison shows an average increase in efficiency of {approx}40%. The polyimide windows have a significantly lower leak rate than the polypropylene windows making it possible to achieve approximately an order of magnitude lower pressure in the spectrometer vacuum chamber which reduces the gas load on the trap region.

  20. Prediction of Launch Vehicle Ignition Overpressure and Liftoff Acoustics

    NASA Technical Reports Server (NTRS)

    Casiano, Matthew

    2009-01-01

    The LAIOP (Launch Vehicle Ignition Overpressure and Liftoff Acoustic Environments) program predicts the external pressure environment generated during liftoff for a large variety of rocket types. These environments include ignition overpressure, produced by the rapid acceleration of exhaust gases during rocket-engine start transient, and launch acoustics, produced by turbulence in the rocket plume. The ignition overpressure predictions are time-based, and the launch acoustic predictions are frequency-based. Additionally, the software can predict ignition overpressure mitigation, using water-spray injection into the rocket exhaust stream, for a limited number of configurations. The framework developed for these predictions is extensive, though some options require additional relevant data and development time. Once these options are enabled, the already extensively capable code will be further enhanced. The rockets, or launch vehicles, can either be elliptically or cylindrically shaped, and up to eight strap-on structures (boosters or tanks) are allowed. Up to four engines are allowed for the core launch vehicle, which can be of two different types. Also, two different sizes of strap-on structures can be used, and two different types of booster engines are allowed. Both tabular and graphical presentations of the predicted environments at the selected locations can be reviewed by the user. The output includes summaries of rocket-engine operation, ignition overpressure time histories, and one-third octave sound pressure spectra of the predicted launch acoustics. Also, documentation is available to the user to help him or her understand the various aspects of the graphical user interface and the required input parameters.

  1. METHOD FOR PUMPING GASES AT LOW VACUUM PRESSURES

    DOEpatents

    Milleron, N.

    1962-06-01

    A method is given for pumping overpressure "pulses" or "bursts" of gases without a significant rise in base pressure within a "gettering-type" vacuum pump having surfaces within the pumping cavity coated with or comprising clean gettering metal, e.g., Mo or Ta. The cavity is first pumped down by any convenient means to an equilibrium base pressure in the range desired, generally below 10/sup -6/ mm Hg. At this pressure, the metal immediately adsorbs overpressures or "bursts" of gases striking same with thermal motion without raising the base pressure significantiy. Desorption takes place at an equilibrium rate which, of course, is dependent upon the equilibrium pressure, and such desorbed gases are continuously removed by diffuaion pump or other pumping, whereby said overpressures or "bursts" of gases are removed without a rise in the equilibrium pressure and/or back diffusion of the gaseous pulse from the pumping cavity. (AEC)

  2. R&D ERL: Vacuum

    SciTech Connect

    Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

    2010-01-01

    The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The

  3. ISABELLE vacuum systems

    SciTech Connect

    Halama, H J

    1980-01-01

    The Intersecting Storage Accelerator (ISABELLE) consists of two rings having a circumference of 3.8 km each. In these rings superconducting magnets, held at 4 K, bend and focus the proton beam which is accelerated up to 400 GeV. Due to very different pressure requirements, ISABELLE has two completely independent vacuum systems. One, which operates at 1 x 10/sup -11/ Torr, provides a very clean environment for the circulating proton beam. Here only ion and titanium sublimation pumps are used to provide the vacuum. The other system maintains superconducting magnet vessels at a pressure below 1 x 10/sup -4/ Torr, since at this pressure the gas conduction becomes negligible. In this so-called insulating vacuum system, turbomolecular pumps pump the inadvertent small helium leaks. Other gases are cryocondensed on the cold surfaces of the cryogenic system. The basic element of ISABELLE known as Full Cell containing 45 meters of beam tube, 8 pumping stations, 8 superconducting magnets and complete instrumentation has been constructed, leak checked and tested. All design parameters have been achieved in both vacuum systems. The two vacuum systems are described with particular emphasis on the influence of superconducting magnets in the selection of materials and UHV components.

  4. Overpressure Prediction From Seismic Data: Implications on Drilling Safety

    NASA Astrophysics Data System (ADS)

    Osinowo, O. O.; Oladunjoye, M. A.; Olayinka, A. I.

    2007-12-01

    High rate of sediment influx into the Niger Delta via river Niger coupled with high rate of basin subsidence, very thick clayey members of Agbada and Akata Formations as well as prevailing presence of growth faults had been identified as the main factors responsible for overpressure generation and preservation in the Niger Delta basin. Analysis of porosity dependent parameters such as interval transit times and interval velocities derived from the seismic records of a field in the Western Niger Delta revealed the presence of overpressured formation at depth of 8670 feet, which is the top of the overpressured zone. The plot of interval transit times against depth gave a positive deflection from normal at the region of overpressure while interval velocity plot gave negative deflection; the ratio of this deviation in both cases is as high as 1.52. Pressure gradient in the upper, normally pressured part of the field was determined to be 0.465 psi/ft., which is within the established normal pressure gradient range in Niger Delta, while the abnormal formation pressure gradient in the overpressured region was determined to be 0.96 psi/ft., and this is also within the published abnormal pressure gradient range of 0.71 to 1.1 psi/ft. in Niger Delta. Formation fracture pressure gradients were determined from the formation pressure information to be 0.66psi/ft. in the upper part of the field and 1.2psi/ft. in the overpressured horizon. Mud weight window (MWW); mud density range necessary to prevent formation kick without initiating hydraulic fracturing was determined to be 10.2 to 12.5lbm/gal in the upper part of the field and 22.1 to 22.63lbm/gal in the overpressured horizon. MWW is indispensable for the selection of the mud pump type, capacity, pumping rate and mud densities at different formation pressure regimes. Overpressure prediction is also requisite for drilling program design, casing design as well as rig capacity choice before spudding. It is necessary to reduce

  5. Overpressure and Its Relation to Petroleum Accumulation in Southern Edge of Junggar Basin

    NASA Astrophysics Data System (ADS)

    Zhao, G.

    2014-12-01

    Abstract: Measured formation pressure, well- log and mud weight data show that there are overpressures in the southern edge of Junggar basin. Vertically, overpressure distribution is not direct ly related to the burial depth, it is mainly controlled by stratigraphic horizons, especially the lower Tertiary Anjihaihe Formation has the most evident control over the overpressures. Horizontally, overpressure occur in the 3 structural belts in southern edge of the basin, but there are differences in the east and in the west : in the eastern part overpressures occur in the Anjihaihe Formation only, while in the western part, they occur not only in the Anjihaihe Formation, but also in the Shawan and Ziniguanzi Formation. Analyzing the relationship between the well test data and overpressures in the southern edge of Junggar basin, it can be found that the distribution of oil and gas reservoirs are closely related to the overpressures. Being affected by faulting, and due to the differences in mechanism of relationship between overpressures and preservation of oil and gas reservoirs, the distribution of overpressures and oil and gas reservoirs cannot be corresponding to one another. As a whole, however, oil and gas would be ready to be reservoired in the normally pressured zone below the moderately abnormal pressured or overpressures zone, which would, therefore, be the favorable target of petroleum exploration; while the overpressured zone with relatively high formation pressure coefficient is unfavorable for oil/ gas reservoiring.

  6. Effect of thickness on physical properties of electron beam vacuum evaporated CdZnTe thin films for tandem solar cells

    NASA Astrophysics Data System (ADS)

    Chander, Subhash; Dhaka, M. S.

    2016-10-01

    The thickness and physical properties of electron beam vacuum evaporated CdZnTe thin films have been optimized in the present work. The films of thickness 300 nm and 400 nm were deposited on ITO coated glass substrates and subjected to different characterization tools like X-ray diffraction (XRD), UV-Vis spectrophotometer, source meter and scanning electron microscopy (SEM) to investigate the structural, optical, electrical and surface morphological properties respectively. The XRD results show that the as-deposited CdZnTe thin films have zinc blende cubic structure and polycrystalline in nature with preferred orientation (111). Different structural parameters are also evaluated and discussed. The optical study reveals that the optical transition is found to be direct and energy band gap is decreased for higher thickness. The transmittance is found to increase with thickness and red shift observed which is suitable for CdZnTe films as an absorber layer in tandem solar cells. The current-voltage characteristics of deposited films show linear behavior in both forward and reverse directions as well as the conductivity is increased for higher film thickness. The SEM studies show that the as-deposited CdZnTe thin films are found to be homogeneous, uniform, small circle-shaped grains and free from crystal defects. The experimental results confirm that the film thickness plays an important role to optimize the physical properties of CdZnTe thin films for tandem solar cell applications as an absorber layer.

  7. Modeling and optimization of sensory changes and shelf-life in vacuum-packaged cooked ham treated by E-beam irradiation

    NASA Astrophysics Data System (ADS)

    Benedito, J.; Cambero, M. I.; Ortuño, C.; Cabeza, M. C.; Ordoñez, J. A.; de la Hoz, L.

    2011-03-01

    The E-beam irradiation of vacuum-packaged RTE cooked ham was carried out to establish the dose required to achieve the food safety objective (FSO) and to minimize changes in selected sensory attributes. Cooked ham was irradiated with doses ranging 1-4 kGy. After the treatment, the microbial inactivation of Listeria monocytogenes, the shelf-life of the product and some sensory attributes (appearance, odor, and flavor) were determined. The inactivation of L. monocytogenes was satisfactorily described by a first-order kinetics equation ( R2=0.99). The influence of the irradiation dose on appearance, odor, and flavor was modeled through Gompertz ( R2=0.99, for appearance) and Activation/Inactivation ( R2=0.99, for odor and flavor) equations. A model was also developed to determine the shelf-life of irradiated cooked ham depending on the irradiation dose ( R2>0.91). The dose that maximized the scores of the sensory attributes was 0.96 kGy resulting in an acceptable sensory quality for 80 days. It is possible to apply up to 2 kGy to ensure microbial safety, while provoking no significant changes in the above mentioned sensory attributes.

  8. Ge quantum dot arrays grown by ultrahigh vacuum molecular-beam epitaxy on the Si(001) surface: nucleation, morphology, and CMOS compatibility.

    PubMed

    Yuryev, Vladimir A; Arapkina, Larisa V

    2011-09-05

    Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C) and high (≳600°C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.

  9. Ge quantum dot arrays grown by ultrahigh vacuum molecular-beam epitaxy on the Si(001) surface: nucleation, morphology, and CMOS compatibility

    PubMed Central

    2011-01-01

    Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C) and high (≳600°C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature. PMID:21892938

  10. Tensile overpressure compartments on low-angle thrust faults

    NASA Astrophysics Data System (ADS)

    Sibson, Richard H.

    2017-08-01

    Hydrothermal extension veins form by hydraulic fracturing under triaxial stress (principal compressive stresses, σ 1 > σ 2 > σ 3) when the pore-fluid pressure, P f, exceeds the least compressive stress by the rock's tensile strength. Such veins form perpendicular to σ 3, their incremental precipitation from hydrothermal fluid often reflected in `crack-seal' textures, demonstrating that the tensile overpressure state, σ 3' = ( σ 3 - P f) < 0, was repeatedly met. Systematic arrays of extension veins develop locally in both sub-metamorphic and metamorphic assemblages defining tensile overpressure compartments where at some time P f > σ 3. In compressional regimes ( σ v = σ 3), subhorizontal extension veins may develop over vertical intervals <1 km or so below low-permeability sealing horizons with tensile strengths 10 < T o < 20 MPa. This is borne out by natural vein arrays. For a low-angle thrust, the vertical interval where the tensile overpressure state obtains may continue down-dip over distances of several kilometres in some instances. The overpressure condition for hydraulic fracturing is comparable to that needed for frictional reshear of a thrust fault lying close to the maximum compression, σ 1. Under these circumstances, especially where the shear zone material has varying competence (tensile strength), affecting the failure mode, dilatant fault-fracture mesh structures may develop throughout a tabular rock volume. Evidence for the existence of fault-fracture meshes around low-angle thrusts comes from exhumed ancient structures and from active structures. In the case of megathrust ruptures along subduction interfaces, force balance analyses, lack of evidence for shear heating, and evidence of total shear stress release during earthquakes suggest the interfaces are extremely weak ( τ < 40 MPa), consistent with weakening by near-lithostatically overpressured fluids. Portions of the subduction interface, especially towards the down-dip termination of

  11. Thermodynamically consistent model of brittle oil shales under overpressure

    NASA Astrophysics Data System (ADS)

    Izvekov, Oleg

    2016-04-01

    The concept of dual porosity is a common way for simulation of oil shale production. In the frame of this concept the porous fractured media is considered as superposition of two permeable continua with mass exchange. As a rule the concept doesn't take into account such as the well-known phenomenon as slip along natural fractures, overpressure in low permeability matrix and so on. Overpressure can lead to development of secondary fractures in low permeability matrix in the process of drilling and pressure reduction during production. In this work a new thermodynamically consistent model which generalizes the model of dual porosity is proposed. Particularities of the model are as follows. The set of natural fractures is considered as permeable continuum. Damage mechanics is applied to simulation of secondary fractures development in low permeability matrix. Slip along natural fractures is simulated in the frame of plasticity theory with Drucker-Prager criterion.

  12. Measurements of sonic-boom overpressures from Apollo space vehicles

    NASA Technical Reports Server (NTRS)

    Hilton, D. A.; Henderson, H. R.

    1974-01-01

    This paper presents representative results of sonic-boom overpressure data recorded during the launch and reentry of the Apollo 15 and 16 space vehicle systems. Comparisons are made between measured overpressures and those predicted using available theory. The measurements were obtained along the vehicle ground track at 68, 87, 92, 129, and 970 km downrange from the launch site during ascent, and at 9, 13, 55, 185, and 500 km from the splash-down point during reentry. Also included are tracings of the sonic-boom signatures along with a brief description of the launch and recovery test areas in which the measurements were obtained, the sonic-boom instrumentation deployment, flight profiles and operating conditions, and high-altitude weather information for the general measurement areas.

  13. Occupational overpressure exposure of breachers and military personnel

    NASA Astrophysics Data System (ADS)

    Kamimori, G. H.; Reilly, L. A.; LaValle, C. R.; Olaghere Da Silva, U. B.

    2017-08-01

    Military and law enforcement personnel may be routinely and repetitively exposed to low-level blast (LLB) overpressure during training and in operations. This repeated exposure has been associated with symptoms similar to that reported for sports concussion. This study reports LLB exposure for various military and law enforcement sources in operational training environments. Peak overpressure and impulse data are presented from indoor breaching, outdoor breaching, shotgun door breaching, small arms discharge, and mortar and artillery fire missions. Data were collected using the Black Box Biometrics (B3) Blast Gauge sensors. In all cases, sensors were attached to the operators and, where possible, also statically mounted to walls or other fixed structures. Peak overpressures from below 1 psi (7 kPa) to over 12 psi (83 kPa) were recorded; all values reported are uncorrected for incidence angle to the blast exposure source. The results of these studies indicate that the current minimum safe distance calculations are often inaccurate for both indoor and outdoor breaching scenarios as true environmental exposure can consistently exceed the 4 psi (28 kPa) incident safe threshold prescribed by U.S. Army doctrine. While ballistic (shotgun) door breaching and small arms firing only expose the operator to low peak exposure levels, the sheer number of rounds fired during training may result in an excessive cumulative exposure. Mortar and artillery crew members received significantly different overpressure and impulse exposures based on their position (job) relative to the weapon. As both the artillery and mortar crews commonly fire hundreds of rounds during a single training session they are also likely to receive high cumulative exposures. These studies serve to provide the research community with estimates for typical operator exposure across a range of operational scenarios or in the discharge of various weapons systems.

  14. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald K.; Liever, Peter A.

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test (SMAT), conducted at Marshall Space Flight Center (MSFC). The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  15. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald; Liever, Peter; Nielsen, Tanner

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test, conducted at Marshall Space Flight Center. The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  16. Distribution and generation of the overpressure system, eastern Delaware Basin, western Texas and southern New Mexico

    SciTech Connect

    Luo, M.; Baker, M.R.; LeMone, D.V.

    1994-09-01

    Three subsurface pressure systems have been identified in the Delaware basin: an upper normal pressure system, a middle overpressure system, and a lower normal pressure system. The overpressure system occurs in the eastern Delaware basin, covering six Texas and New Mexico counties. The depth of the overpressure system ranges from 3100 to 5400 m. The normal fluid pressure gradient is 0.0103 MPa/m in the eastern Delaware basin. The highest overpressure gradient, however, approaches 0.02 MPa/m, which is close to the lithostatic gradient of 0.0231 MPa/m. An area of excess pressure occurs within the system where the highest excess pressure reaches 60 MPa. Local underpressured areas due to production are found in the lower normal pressure system in the War-Wink field area. Overpressure in the eastern Delaware basin is mainly associated with Mississippian, Pennsylvanian, and Permian (Wolfcampian) shale sequences, which also are major source rocks in the basin. Corrected bottom-hole temperature measurements indicate that the geothermal gradient within the overpressure zone is 25.1{degrees}C/km, which is higher than the basin`s average geothermal gradient of 21{degrees}C/km. Temperatures at the top and bottom of the overpressure system are about 80 and 115{degrees}C, respectively. The oil window in the War-Wink field is coincident with the overpressure system, which implies that hydrocarbon generation and migration are active in the overpressure system. A two-stage overpressure model is proposed. Hydrocarbon maturation combined with mechanical compaction disequilibrium and clay dehydration are the initial causes for overpressure generation due to an abnormal increase of fluid volume and pore space. Subsequently, the increase in temperature due to a decrease of thermal conductivity and fluid migration within the preexisting overpressure system would reinforce further overpressuring due to the fluid thermal expansion.

  17. APS storage ring vacuum system

    SciTech Connect

    Niemann, R.C.; Benaroya, R.; Choi, M.; Dortwegt, R.J.; Goeppner, G.A.; Gonczy, J.; Krieger, C.; Howell, J.; Nielsen, R.W.; Roop, B.; Wehrle, R.B.

    1990-01-01

    The Advanced Photon Source synchrotron radiation facility, under construction at the Argonne National Laboratory, incorporates a large ring for the storage of 7 GeV positrons for the generation of photon beams for the facility's experimental program. The Storage Ring's 1104 m circumference is divided into 40 functional sectors. The sectors include vacuum, beam transport, control, acceleration and insertion device components. The vacuum system, which is designed to operate at a pressure of 1 n Torr, consists of 240 connected sections, the majority of which are fabricated from an aluminum alloy extrusion. The sections are equipped with distributed NeG pumping, photon absorbers with lumped pumping, beam position monitors, vacuum diagnostics and valving. The details of the vacuum system design, selected results of the development program and general construction plans are presented. 11 refs., 6 figs., 3 tabs.

  18. Vacuum fiber-fiber coupler

    NASA Astrophysics Data System (ADS)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe

    2017-02-01

    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  19. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum.

    PubMed

    de Oliveira, N; Joyeux, D; Phalippou, D; Rodier, J C; Polack, F; Vervloet, M; Nahon, L

    2009-04-01

    We describe a Fourier transform (FT) spectrometer designed to operate down to 60 nm (20 eV) on a synchrotron radiation beamline for high resolution absorption spectrometry. As far as we know, such an instrument is not available below 140 nm mainly because manufacturing accurate and efficient beam splitters remains a major problem at these wavelengths, especially if a wide bandwidth operation is desired. In order to overcome this difficulty, we developed an interferometer based on wave front division instead of amplitude division. It relies on a modified Fresnel bimirror configuration that requires only flat mirrors. The instrument provides path difference scanning through the translation of one reflector. During the scanning, the moving reflector is controlled by an optical system that keeps its direction constant within a tolerable value and provides an accurate interferometric measurement of the path difference variation. Therefore, a regular interferogram sampling is obtained, producing a nominal spectral impulse response and an accurate spectral calibration. The first results presented in this paper show a measured spectral resolution of delta(sigma)=0.33 cm-1 (interval between spectral samples). This was obtained with a sampling interval of 29 nm (path difference) and 512 K samples from a one-sided interferogram using a cosine FT. Such a sampling interval should allow the recording of large bandwidth spectra down to lambda=58 nm with an ultimate resolving power of 500,000 at this wavelength. In order to check the instrument performances, we first recorded an interferogram from a He-Ne stabilized laser. This provided the actual spectral impulse function, which was found to be fully satisfactory. The determination of the impulse response distortion and of the noise on the vacuum ultraviolet (VUV) spectral range provided accurate information in the sampling error profile over a typical scan. Finally, the instrument has been moved to the SU5 undulator

  20. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum

    SciTech Connect

    Oliveira, N. de; Polack, F.; Vervloet, M.; Nahon, L.; Joyeux, D.; Phalippou, D.; Rodier, J. C.

    2009-04-15

    We describe a Fourier transform (FT) spectrometer designed to operate down to 60 nm (20 eV) on a synchrotron radiation beamline for high resolution absorption spectrometry. As far as we know, such an instrument is not available below 140 nm mainly because manufacturing accurate and efficient beam splitters remains a major problem at these wavelengths, especially if a wide bandwidth operation is desired. In order to overcome this difficulty, we developed an interferometer based on wave front division instead of amplitude division. It relies on a modified Fresnel bimirror configuration that requires only flat mirrors. The instrument provides path difference scanning through the translation of one reflector. During the scanning, the moving reflector is controlled by an optical system that keeps its direction constant within a tolerable value and provides an accurate interferometric measurement of the path difference variation. Therefore, a regular interferogram sampling is obtained, producing a nominal spectral impulse response and an accurate spectral calibration. The first results presented in this paper show a measured spectral resolution of {delta}{sigma}=0.33 cm{sup -1} (interval between spectral samples). This was obtained with a sampling interval of 29 nm (path difference) and 512 K samples from a one-sided interferogram using a cosine FT. Such a sampling interval should allow the recording of large bandwidth spectra down to {lambda}=58 nm with an ultimate resolving power of 500 000 at this wavelength. In order to check the instrument performances, we first recorded an interferogram from a He-Ne stabilized laser. This provided the actual spectral impulse function, which was found to be fully satisfactory. The determination of the impulse response distortion and of the noise on the vacuum ultraviolet (VUV) spectral range provided accurate information in the sampling error profile over a typical scan. Finally, the instrument has been moved to the SU5 undulator

  1. Electrostatic Levitator Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical ports ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (beam passes through the window at left), positioning lasers (one port is at center), and lamps to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  2. 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.

  3. Vacuum Technology

    SciTech Connect

    Biltoft, P J

    2004-10-15

    The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

  4. 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…

  5. 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…

  6. 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.

  7. Experimental magnesium depletion in adult rabbits caused by blast overpressure.

    PubMed

    Cernak, I; Radosevic, P; Malicevic, Z; Savic, J

    1995-09-01

    The complex pressure wave (blast) generated by some explosions causes pulmonary pathological changes which resemble the histological findings of the adult respiratory distress syndrome (ARDS). The development of indirect neurotrauma following experimental pulmonary blast injury has been shown previously. The purpose of this study was to evaluate lung and brainstem total tissue magnesium concentrations in adult rabbits following pulmonary blast injury. In order to assess the interrelationship between magnesium and other secondary injury factors, total calcium and high energy phosphate (phosphocreatine, PCr; adenosine triphosphate, ATP) contents were simultaneously measured. Twenty adult male rabbits were divided into two groups. Group C (n = 10) served as control, while group B (n = 10) was subjected to a focused blast wave, generated in laboratory conditions using an air-driven shock tube. Moderate pulmonary blast injury was verified by histological examination in group B. Total tissue magnesium and calcium contents were measured by atomic absorption spectrophotometry in the lungs and brainstem of adult rabbits 30 min following blast overpressure and in their uninjured controls. Simultaneously, PCr and ATP contents were measured by fluorimetric enzymatic analyses in same structures. Lung and brainstem water contents were determined by wet weight to dry weight ratio. Blast overpressure to the lungs induced significant magnesium depletion, increased calcium and decreased the Mg/Ca ratio in lung tissue of injured animals. Increases in water content and PCr/ATP ratio were also observed. Significant correlations between these Mg/Ca and PCr/ATP and between Mg and ATP parameters confirmed the functional relationship between magnesium depletion and impaired bioenergetic state in indirect neurotrauma in adult rabbits through blast overpressure.

  8. Gravitational vacuum

    NASA Astrophysics Data System (ADS)

    Grigoryan, L. S.; Saakyan, G. S.

    1984-09-01

    The existence of a special gravitational vacuum is considered in this paper. A phenomenological method differing from the traditional Einsteinian formalization is utilized. Vacuum, metric and matter form a complex determined by field equations and at great distances from gravitational masses vacuum effects are small but could be large in powerful fields. Singularities and black holes justify the approach as well as the Ambartsmyan theory concerning the existence of supermassive and superdense prestallar bodies that then disintegrate. A theory for these superdense bodies is developed involving gravitational field equations that describe the vacuum by an energy momentum tensor and define the field and mass distribution. Computations based on the theory for gravitational radii with incompressible liquid models adequately reflecting real conditions indicate that a gravitational vacuum could have considerable effects on superdense stars and could have radical effects for very large masses.

  9. Cleaning validation procedure eased by using overpressured layer chromatography.

    PubMed

    Katona, Z; Vincze, L; Végh, Z; Trompler, A; Ferenczi-Fodor, K

    2000-03-01

    In the manufacturing plants of many pharmaceutical companies the reaction apparatus is suitable to produce different active pharmaceutical ingredients. After completing the production of a compound the equipment should be cleaned in order to avoid the cross contamination in the next lot of the other products. In the authors' laboratory several chromatographic methods were introduced to measure the amount of the residual substances remaining on the surface of the apparatus after the cleaning procedure. A sensitive and fairly rapid overpressured layer chromatographic (OPLC) procedure--suitable to separate and control five steroid hormone compounds (allylestrenol, estradiol, ethynodiol diacetate, levonorgestel, norethisterone) produced in the same equipment at different times--was developed and validated.

  10. Effects of blast overpressure on the ear: case reports.

    PubMed

    Chandler, D W; Edmond, C V

    1997-04-01

    The case histories of five patients who experienced blast overpressure in excess of 200-dB peak pressure level are presented. Despite the significance of the sound pressure levels received in a military training accident and the severe injuries that resulted from the blast, these individuals experienced substantial improvement of hearing 1 year later. Undoubtedly, successful surgical intervention and medical management were the primary contributors to the restoration of hearing. Audiometric data are presented documenting hearing status within 2 to 3 weeks postinjury and following final surgical remediation of the resulting middle ear damage. A review of these cases offers insight into the possible prognosis of patients with similar injuries.

  11. Growth of CdZnTe Crystals the Bridgman Technique with Controlled Overpressures of Cd

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hu; Lehoczky, S. L.

    2008-01-01

    Cd(1-x)Zn(x)Te crystals with x = 0.15 and 0.20, were grown in this study by closed-ampoule directional solidification (Bridgman) technique with a controlled Cd overpressure. The growth ampoule was made of quartz with inner diameter from 20 to 40 mm and a tapered length of 2.5 cm at the growth tip. Both unseeded and seeded growths were performed with total material charges up to 400 g. After the loading of starting CdZnTe material, a typical amount of 2 g of Cd was also loaded inside a Cd reservoir basket, which was attached beneath the seal-off cup. The ampoule was sealed off under a vacuum below lxl0(exp -5) Torr. The sealed ampoule was placed inside a 4-zone Bridgman furnace - a Cd reservoir zone with a heat-pipe furnace liner on the top, followed by a hot zone, a booster heating zone and a cold zone at the bottom. The Cd zone was typically 300 to 400 C below the hot zone setting. High resistivity material has been obtained without any intentional dopants but has been reproducibly obtained with In doping. The crystalline and the electrical properties of the crystals will be reported.

  12. Vacuum Beat Wave Accelerator

    NASA Astrophysics Data System (ADS)

    Moore, C. I.; Hafizi, B.; Ting, A.; Burris, H. R.; Sprangle, P.; Esarey, E.; Ganguly, A.; Hirshfield, J. L.

    1997-11-01

    The Vacuum Beat Wave Accelerator (VBWA) is a particle acceleration scheme which uses the non-linear ponderomotive beating of two different frequency laser beams to accelerate electrons. A proof-of-principle experiment to demonstrate the VBWA is underway at the Naval Research Laboratory (NRL). This experiment will use the beating of a 1054 nm and 527 nm laser pulse from the NRL T-cubed laser to generate the beat wave and a 4.5 MeV RF electron gun as the electron source. Simulation results and the experimental design will be presented. The suitability of using axicon or higher order Gaussian laser beams will also be discussed.

  13. Accelerator Vacuum Protection System

    NASA Astrophysics Data System (ADS)

    Barua, Pradip; Kothari, Ashok; Archunan, M.; Joshi, Rajan

    2012-11-01

    A new and elaborate automatic vacuum protection system using fast acting valve has been installed to avoid accidental venting of accelerator from experimental chamber side. To cover all the beam lines and to reduce the system cost, it has been installed at a common point from where all the seven beam lines originate. The signals are obtained by placing fast response pressure sensing gauges (HV SENSOR) near all the experimental stations. The closing time of the fast valve is 10 milli-second. The fast closing system protects only one vacuum line at a time. At IUAC, we have seven beam lines so one sensor was placed in each of the beam lines near experimental chamber and a multiplexer was incorporated into the fast closing system. At the time of experiment, the sensor of the active beam line is selected through the multiplexer and the Fast closing valve is interlocked with the selected sensor. As soon as the pressure sensor senses the pressure rise beyond a selected pressure, the signal is transferred and the fast valve closes within 10 to 12 millisecond.

  14. Design of a modular and versatile interlock system for ultrahigh vacuum machines: A crossed molecular beam setup as a case study

    NASA Astrophysics Data System (ADS)

    Guo, Ying; Gu, Xibin; Kawamura, Ed; Kaiser, Ralf I.

    2006-03-01

    The design of a modular, versatile interlock system for ultrahigh vacuum machines is presented. This system can monitor the pressure (ultrahigh vacuum and high vacuum), the status of the power (power failure, power fluctuations, and scheduled power outages), the operation mode of the pumps (operation versus failure), the flow of cooling water, the humidity and temperature levels in the laboratory, as well as the concentration of toxic gases. If any of the set points is triggered, the vacuum machine is protected fully automatically. The interlock system is also interfaced to an automated paging system, thus transmitting a pager signal to the person on duty. Since the interlock system is modular in nature, it can be expanded and be adapted stepwise to incorporate additional safety and monitoring functions as needed.

  15. Membrane characteristics for biological blast overpressure testing using blast simulators.

    PubMed

    Alphonse, Vanessa D; Siva Sai Sujith Sajja, Venkata; Kemper, Andrew R; Rizel, Dave V; Duma, Stefan M; VandeVord, Pamela J

    2014-01-01

    Blast simulators often use passive-rupture membranes to generate shock waves similar to free-field blasts. The purpose of this study was to compare rupture patterns and pressure traces of three distinct membrane materials for biological and biomechanical blast studies. An Advanced Blast Simulator (ABS) located at the Center for Injury Biomechanics at Virginia Tech was used to test membrane characteristics. Acetate, Mylar, and aluminum sheets with different thicknesses were used to obtain pressures between 70–210 kPa. Static pressure was measured inside the tube at the test section using piezoelectric pressure sensors. Peak overpressure, positive duration, and positive impulse were calculated for each test. Rupture patterns and characteristic pressure traces were unique to each membrane type and thickness. Shock wave speed ranged between 1.2-1.8 Mach for static overpressures of 70–210 kPa. Acetate membranes fragmented sending pieces down the tube, but produced ideal (Friedlander) pressure traces. Mylar membranes bulged without fragmenting, but produced less-than-ideal pressure traces. Aluminum membranes did not fragment and produced ideal pressure traces. However, the cost of manufacturing and characterizing aluminum membranes should be considered during membrane selection. This study illustrates the advantages and disadvantages of using Mylar, acetate, and aluminum for passive rupture membranes for blast simulators.

  16. 49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Overpressure safety devices and overfill protection systems. 195.428 Section 195.428 Transportation Other Regulations Relating to Transportation... Overpressure safety devices and overfill protection systems. (a) Except as provided in paragraph (b) of this...

  17. 49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Overpressure safety devices and overfill protection systems. 195.428 Section 195.428 Transportation Other Regulations Relating to Transportation... Overpressure safety devices and overfill protection systems. (a) Except as provided in paragraph (b) of this...

  18. 49 CFR 195.428 - Overpressure safety devices and overfill protection systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Overpressure safety devices and overfill protection systems. 195.428 Section 195.428 Transportation Other Regulations Relating to Transportation... Overpressure safety devices and overfill protection systems. (a) Except as provided in paragraph (b) of this...

  19. The AGS Booster vacuum systems

    SciTech Connect

    Hseuh, H.C.

    1989-01-01

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10{sup {minus}11} mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200{degree}C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs.

  20. Vacuum applications of metal foams

    NASA Technical Reports Server (NTRS)

    Kendall, B. R. F.

    1980-01-01

    Several vacuum applications of copper foams in the density range 2-5% and pore sizes of 0.5-0.7 mm are discussed, such as a foreline hydrocarbon trap in a mechanical vacuum pump, a molecular-flow resistor, a diffuser, and a water injector. Other suggested applications include the use of foam copper in the form of an externally heated plug to remove traces of oxygen from inert gases bled into a vacuum system through a stainless steel line and the use of the porous surface for minimizing release of secondary electrons from electrodes in the path of charged particle beams.

  1. Thermal Vacuum Chamber Repressurization with Instrument Purging

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2016-01-01

    At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

  2. Thermal vacuum chamber repressurization with instrument purging

    NASA Astrophysics Data System (ADS)

    Woronowicz, Michael S.

    2016-09-01

    At the conclusion of cryogenic vacuum testing of the James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (JWST-OTIS) in NASA Johnson Space Center's (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are postulating that chamber particulate material stirred up by the repressurization process may be kept from falling into the Integrated Science Instrument Module (ISIM) interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This manuscript describes development of a series of models designed to describe this process. The models are strung together in tandem with a fictitious set of conditions to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

  3. Thermal Vacuum Chamber Repressurization with Instrument Purging

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2017-01-01

    At the end of James Webb Space Telescope (JWST) OTIS (Optical Telescope Element-OTE-Integrated Science Instrument Module-ISIM) cryogenic vacuum testing in NASA Johnson Space Centers (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are mooting the idea that chamber particulate material stirred up by the repressurization process may be kept from falling into the ISIM interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This memo describes development of a series of models designed to describe this process. These are strung together in tandem to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

  4. Thermal Vacuum Chamber Repressurization with Instrument Purging

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael S.

    2014-01-01

    At the conclusion of cryogenic vacuum testing of the James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (JWST-OTIS) in NASA Johnson Space Center’s (JSCs) thermal vacuum (TV) Chamber A, contamination control (CC) engineers are postulating that chamber particulate material stirred up by the repressurization process may be kept from falling into the Integrated Science Instrument Module (ISIM) interior to some degree by activating instrument purge flows over some initial period before opening the chamber valves. This manuscript describes development of a series of models designed to describe this process. The models are strung together in tandem with a fictitious set of conditions to estimate overpressure evolution from which net outflow velocity behavior may be obtained. Creeping flow assumptions are then used to determine the maximum particle size that may be kept suspended above the ISIM aperture, keeping smaller particles from settling within the instrument module.

  5. Experimental study of near-field entrainment of moderately overpressured jets

    USGS Publications Warehouse

    Solovitz, S.A.; Mastin, L.G.; Saffaraval, F.

    2011-01-01

    Particle image velocimetry (PIV) experiments have been conducted to study the velocity flow fields in the developing flow region of high-speed jets. These velocity distributions were examined to determine the entrained mass flow over a range of geometric and flow conditions, including overpressured cases up to an overpressure ratio of 2.83. In the region near the jet exit, all measured flows exhibited the same entrainment up until the location of the first shock when overpressured. Beyond this location, the entrainment was reduced with increasing overpressure ratio, falling to approximately 60 of the magnitudes seen when subsonic. Since entrainment ratios based on lower speed, subsonic results are typically used in one-dimensional volcanological models of plume development, the current analytical methods will underestimate the likelihood of column collapse. In addition, the concept of the entrainment ratio normalization is examined in detail, as several key assumptions in this methodology do not apply when overpressured.

  6. Vacuum-Ultraviolet Intensity-Calibration Standard

    NASA Technical Reports Server (NTRS)

    Ajello, J. M.; Franklin, B. O.

    1986-01-01

    Portable light source enables calibration of spectrometers. Vacuum Ultraviolet Light (40 to 200 nm) produced in electron-impact emission chamber by leading beam of gas across electron beam. Photons observed at right angles to electron-beam axis. Previously, there were blackbody standards in visible and near ultraviolet, but no intensity-calibration standards in VUV.

  7. Blastwall effects on down range explosively-induced overpressure.

    SciTech Connect

    Saul, W. Venner; Preece, Dale S.

    2003-07-01

    Blastwalls are often assumed to be the answer for facility protection from malevolent explosive assault, particularly from large vehicle bombs (LVB's). The assumption is made that the blastwall, if it is built strong enough to survive, will provide substantial protection to facilities and people on the side opposite the LVB. This paper will demonstrate through computer simulations and experimental data the behavior of explosively induced air blasts during interaction with blastwalls. It will be shown that air blasts can effectively wrap around and over blastwalls. Significant pressure reduction can be expected on the downstream side of the blastwall but substantial pressure will continue to propagate. The effectiveness of the blastwall to reduce blast overpressure depends on the geometry of the blastwall and the location of the explosive relative to the blastwall.

  8. Ares I-X Post Flight Ignition Overpressure Review

    NASA Technical Reports Server (NTRS)

    Alvord, David A.

    2010-01-01

    Ignition Overpressure (IOP) is an unsteady fluid flow and acoustic phenomena caused by the rapid expansion of gas from the rocket nozzle within a ducted launching space resulting in an initially higher amplitude pressure wave. This wave is potentially dangerous to the structural integrity of the vehicle. An in-depth look at the IOP environments resulting from the Ares I-X Solid Rocket Booster configuration showed high correlation between the pre-flight predictions and post-flight analysis results. Correlation between the chamber pressure and IOP transients showed successful acoustic mitigation, containing the strongest IOP waves below the Mobile Launch Pad deck. The flight data allowed subsequent verification and validation of Ares I-X unsteady fluid ducted launcher predictions, computational fluid dynamic models, and strong correlation with historical Shuttle data.

  9. Blast overpressure after tire explosion: a fatal case.

    PubMed

    Pomara, Cristoforo; D'Errico, Stefano; Riezzo, Irene; Perilli, Gabriela; Volpe, Umberto; Fineschi, Vittorio

    2013-12-01

    Fatal blast injuries are generally reported in literature as a consequence of the detonation of explosives in war settings. The pattern of lesion depends on the position of the victim in relation to the explosion, on whether the blast tracks through air or water, and whether it happens in the open air or within an enclosed space and the distance from the explosion. Tire explosion-related injuries are rarely reported in literature. This study presents a fatal case of blast overpressure due to the accidental explosion of a truck tire occurring in a tire repair shop. A multidisciplinary approach to the fatality involving forensic pathologists and engineers revealed that the accidental explosion, which caused a series of primary and tertiary blast wave injuries, was due to tire deterioration.

  10. Middle ear overpressure treatment of endolymphatic hydrops in guinea pigs.

    PubMed

    Sakikawa, Y; Kimura, R S

    1997-01-01

    Guinea pigs placed outside or inside a pressure chamber and exposed to 49.2 cm H2O overpressure continuously for 24 h immediately after blockage of the endolymphatic duct showed no significant difference in the magnitude of endolymphatic hydrops when compared to controls, although there was a slight indication of a volume decrease in the outside-treatment group and an increase in the inside-treatment group. A pressure increase of 49.2 cm H2O in the external auditory canal for 1 h twice a day for 2 weeks outside the chamber significantly inhibited the development of hydrops. The latter result supports the merit of pressure application through the external auditory canal as a treatment for Meniere's disease.

  11. Ballistic range investigation of sonic-boom overpressures in water.

    NASA Technical Reports Server (NTRS)

    Malcolm, G. N.; Intrieri, P. F.

    1972-01-01

    An investigation of sonic-boom overpressures in water has been conducted by gun-launching small cone-cylinder models over water. Flights were conducted at Mach numbers of 2.7 and 5.7, in air, corresponding to Mach numbers of 0.6 and 1.3, respectively, in water. Shadowgraph pictures and underwater pressure measurements indicate that for horizontal flights at Mach numbers below Mach 4.4 in air (i.e., subsonic relative to the speed of sound in water) the resulting underwater disturbance is an acoustic wave whose peak pressure attenuates rapidly with water depth. In contrast, at supersonic Mach numbers, relative to water, the incident shock wave at the surface is transmitted into the water as a propagating shock wave and the peak pressure associated with it does not attenuate with water depth.

  12. In-vacuum exposure shutter

    DOEpatents

    Johnson, Terry A.; Replogle, William C.; Bernardez, Luis J.

    2004-06-01

    An in-vacuum radiation exposure shutter device can be employed to regulate a large footprint light beam. The shutter device includes (a) a source of radiation that generates an energy beam; (2) a shutter that includes (i) a frame defining an aperture toward which the energy beam is directed and (ii) a plurality of blades that are secured to the frame; and (3) device that rotates the shutter to cause the plurality of blades to intercept or allow the energy beam to travel through the aperture. Each blade can have a substantially planar surface and the plurality of blades are secured to the frame such that the planar surfaces of the plurality of blades are substantially parallel to each other. The shutter device is particularly suited for operation in a vacuum environment and can achieve shuttering speeds from about 0.1 second to 0.001 second or faster.

  13. Measurements of Vacuum Ultraviolet Radiation, Neutrons, and Ions from the Interaction of an Intense Relativistic Electron Beam and a Deuterated Polyethylene Target.

    DTIC Science & Technology

    diagnostics sensitive to vacum ultraviolet and neutron radiation. Target plasmas produced by three electron accelerators were analyzed. X-ray pinhole...conversion efficiencies of approximately 0.1% from electron beam energy to X-ray radiation were measured. Neutron production was attributed to the beam

  14. Electrostatic Levitator Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Optical prots ring the Electrostatic Levitator (ESL) vacuum chamber to admit light from the heating laser (the beam passes through the window at left), poisitioning lasers (one port is at center), and lamps (such as the deuterium arc lamp at right), and to allow diagnostic instruments to view the sample. The ESL uses static electricity to suspend an object (about 2-3 mm in diameter) inside a vacuum chamber while a laser heats the sample until it melts. This lets scientists record a wide range of physical properties without the sample contacting the container or any instruments, conditions that would alter the readings. The Electrostatic Levitator is one of several tools used in NASA's microgravity materials science program.

  15. Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

    SciTech Connect

    Flanagan, Gene; Johnson, Rolland

    2016-02-18

    High field superconducting magnets are used in particle colliders, fusion energy devices, and spectrometers for medical imaging and advanced materials research. Magnets capable of generating fields of 20-30 T are needed by future accelerator facilities. A 20-30 T magnet will require the use of high-temperature superconductors (HTS) and therefore the challenges of high field HTS magnet development need to be addressed. Superconducting Bi2Sr2CaCu2Ox (Bi2212) conductors fabricated by the oxide-powder-in-tube (OPIT) technique have demonstrated the capability to carry large critical current density of 105 A/cm2 at 4.2 K and in magnetic fields up to 45 T. Available in round wire multi-filamentary form, Bi2212 may allow fabrication of 20-50 T superconducting magnets. Until recently the performance of Bi2212 has been limited by challenges in realizing high current densities (Jc ) in long lengths. This problem now is solved by the National High Magnetic Field Lab using an overpressure (OP) processing technique, which uses external pressure to process the conductor. OP processing also helps remove the ceramic leakage that results when Bi-2212 liquid leaks out from the sheath material and reacts with insulation, coil forms, and flanges. Significant advances have also been achieved in developing novel insulation materials (TiO2 coating) and Ag-Al sheath materials that have higher mechanical strengths than Ag-0.2wt.% Mg, developing heat treatment approaches to broadening the maximum process temperature window, and developing high-strength, mechanical reinforced Bi-2212 cables. In the Phase I work, we leveraged these new opportunities to prototype overpressure processed solenoids and test them in background fields of up to 14 T. Additionally a design of a fully superconducting 30 T solenoid was produced. This work in conjunction with the future path outlined in the Phase II proposal would

  16. Time-resolved HAXPES using a microfocused XFEL beam: From vacuum space-charge effects to intrinsic charge-carrier recombination dynamics

    PubMed Central

    Oloff, Lars-Philip; Chainani, Ashish; Matsunami, Masaharu; Takahashi, Kazutoshi; Togashi, Tadashi; Osawa, Hitoshi; Hanff, Kerstin; Quer, Arndt; Matsushita, Ryuki; Shiraishi, Ryutaro; Nagashima, Maki; Kimura, Ayato; Matsuishi, Kotaro; Yabashi, Makina; Tanaka, Yoshihito; Rossi, Giorgio; Ishikawa, Tetsuya; Rossnagel, Kai; Oura, Masaki

    2016-01-01

    Time-resolved hard X-ray photoelectron spectroscopy (trHAXPES) using microfocused X-ray free-electron laser (XFEL, hν = 8 keV) pulses as a probe and infrared laser pulses (hν = 1.55 eV) as a pump is employed to determine intrinsic charge-carrier recombination dynamics in La:SrTiO3. By means of a combination of experiments and numerical N-body simulations, we first develop a simple approach to characterize and decrease XFEL-induced vacuum space-charge effects, which otherwise pose a serious limitation to spectroscopy experiments. We then show that, using an analytical mean-field model, vacuum space-charge effects can be counteracted by pump laser-induced photoholes at high excitation densities. This provides us a method to separate vacuum space-charge effects from the intrinsic charge-carrier recombination dynamics in the time domain. Our trHAXPES results thus open a route to studies of intrinsic charge-carrier dynamics on picosecond time scales with lateral spatial resolution on the micrometer scale. PMID:27731408

  17. 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.

  18. Lung injury and recovery after exposure to blast overpressure.

    PubMed

    Chavko, Mikulas; Prusaczyk, W Keith; McCarron, Richard M

    2006-10-01

    A critical immediate determinant of survival after exposure to blast overpressure (BOP) is pulmonary damage, but mechanisms of injury and the course of recovery are not well understood. The objective of this study was to characterize the progression of oxidative and inflammatory responses in lungs as well as the activation of consequent protective mechanisms after exposure to medium intensity BOP. Rats were exposed to a moderate (approximately 120 kPa) level of BOP in a pneumatically driven shock tube. At different times (2-192 hours) after exposure, lungs were examined for pathologic signs of injury, markers of inflammatory responses, and indicators of oxidative and nitrative damage. The results showed a postblast activation of inflammatory response (increase of myeloperoxidase activity, CINC-1, ICAM-1, and iNOS), increase in protein oxidation and nitration, and development of gross diffused hemorrhage in lungs. The initial phase of lung damage that peaked at 24 to 48 hours after exposure to BOP was followed by gradual dissolution of inflammation and oxidation that were complete by 192 hours. Resolution of morphologic damage and inflammation in lungs concurred with activation of expression of antioxidant enzymes heme oxygenase-1 (HO-1) and manganese superoxide dismutase (MnSOD). Plasma level of gelsolin, a marker of acute lung damage was decreased at 24 hours postblast and later returned to the control level. The study shows the role of adaptive anti-oxidant and anti- inflammatory mechanisms in lung recovery after injury caused by exposure to BOP.

  19. A complete high integrity overpressure pipeline protection system

    SciTech Connect

    High, G.; Loth, W.D.

    1995-12-31

    Although most often associated with high-pressure production, a reliable system enabling subsea wells to be produced safely at long tie-back distances through flowlines rated to less than shut-in wellhead pressure offers cost savings for many developments. Previous work has shown that there is a small but finite probability of conventional flow control systems failing to shut off damaging overpressures. In most cases, this will arise from mechanical problems which are more likely causes than electronic failure within the production control system. The proposed system provides a viable means of implementing a pressure specification break through the use of a modular, configurable system comprising four main components. The system is semi-autonomous, with dedicated pressure sensors and high integrity electronics being incorporated to avoid common mode system failures. Routine telemetry and reset capability would be conducted through the electro-hydraulic production control system. The near-term availability of this protection system is an important consideration in justifying the economic viability of many marginal field developments.

  20. The development of a cryogenic over-pressure pump

    NASA Astrophysics Data System (ADS)

    Alvarez, M.; Cease, H.; Flaugher, B.; Flores, R.; Garcia, J.; Lathrop, A.; Ruiz, F.

    2014-01-01

    A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL).

  1. NASTRAN Analysis Comparison to Shock Tube Tests Used to Simulate Nuclear Overpressures

    NASA Technical Reports Server (NTRS)

    Wheless, T. K.

    1985-01-01

    This report presents a study of the effectiveness of the NASTRAN computer code for predicting structural response to nuclear blast overpressures. NASTRAN's effectiveness is determined by comparing results against shock tube tests used to simulate nuclear overpressures. Seven panels of various configurations are compared in this study. Panel deflections are the criteria used to measure NASTRAN's effectiveness. This study is a result of needed improvements in the survivability/vulnerability analyses subjected to nuclear blast.

  2. Kevlar Vest Protection Against Blast Overpressure Brain Injury: Systemic Contributions to Injury Etiology

    DTIC Science & Technology

    2014-11-01

    Award Number: W81XWH-08-2-0017 TITLE: " Kevlar Vest Protection Against Blast Overpressure Brain Injury: Systemic Contributions to Injury Etiology...TITLE AND SUBTITLE 5a. CONTRACT NUMBER “ Kevlar Vest Protection Against Blast Overpressure Brain Injury: Systemic Contributions to Injury Etiology...traumatic brain injury (bTBI) is largely undefined. Along with reducing mortality, in preliminary experiments Kevlar vests significantly protected

  3. The quantitative assessment of domino effect caused by overpressure. Part II. Case studies.

    PubMed

    Cozzani, Valerio; Salzano, Ernesto

    2004-03-19

    A quantitative assessment of the contribution to industrial risk of domino effect due to overpressure was undertaken by using the damage probability models developed in part I. Two case studies derived from the actual lay-out of an oil refinery were analyzed. Individual and societal risk indexes were estimated both in the absence and in the presence of the domino effects caused by overpressure. An increase of individual risk up to an order of magnitude was found when considering domino effects.

  4. Overpressure and noise due to multiple airbag systems in a passenger car

    NASA Astrophysics Data System (ADS)

    Hickling, Robert; Henning, Peter J.; Newton, Gary, Jr.

    2002-11-01

    Multiple airbag systems in passenger cars can generate overpressure and noise that may be hazardous to human hearing. Overpressure is compression of the air inside a closed compartment caused by deployment of the bags. Noise results from the action of the gas inflating the bags. SAE J247 provides a standard for measuring the combination of overpressure and noise in a passenger compartment. A special microphone has recently been developed that meets this standard, which operates down to a fraction of a hertz. Details of the microphone are given. Little appears to have been published on the overpressure and noise of modern multiple airbag systems, but early results [R. Hickling, ''The noise of the automotive safety air cushion,'' Noise Control Eng., May-June, 110-121 (1976)] provide a basic understanding of the phenomenon. Spectral data shows that peak overpressure occurs at about 2 to 3 Hz. A significant reduction in overpressure and noise can be achieved with an aspirating airbag, originally developed at General Motors, whose outer structure is inflated with gas from the inflator, and whose inner structure draws in air from the passenger compartment through one-way cloth valves. Tests have shown that such bags function well when impacted.

  5. 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.

  6. Report of the Synchrotron Radiation Vacuum Workshop

    SciTech Connect

    Avery, R.T.

    1984-06-01

    The Synchrotron Radiation Vacuum Workshop was held to consider two vacuum-related problems that bear on the design of storage rings and beam lines for synchrotron radiation facilities. These problems are gas desorption from the vacuum chamber walls and carbon deposition on optical components. Participants surveyed existing knowledge on these topics and recommended studies that should be performed as soon as possible to provide more definitive experimental data on these topics. This data will permit optimization of the final design of the Advanced Light Source (ALS) and its associated beam lines. It also should prove useful for other synchrotron radiation facilities as well.

  7. LHC World Largest Vacuum Systems Being Commissioned at CERN

    NASA Astrophysics Data System (ADS)

    Jimenez, Jose Miguel

    The CERN Large Hadron Collider (LHC) with its 26.7 km of circumference and three different vacuum systems for the beams and insulation vacuum for magnets and liquid helium transfer lines, will have the world's largest vacuum system operating over a wide range of pressures and employing an impressive array of vacuum technologies. This system is composed by 54 km of UHV vacuum for the circulating beams and 50 km of insulation vacuum. Over the 54 km of UHV beam vacuum, 48 km of this are at cryogenic temperature (1.9 K). The remaining 6 km of beam vacuum containing the insertions for “cleaning” the proton beams, radiofrequency cavities for accelerating the protons as well as beam-monitoring equipment is at ambient temperature and uses non-evaporable getter (NEG) coatings. The noble gases and methane is pumped out by 780 ion pumps. Pressure readings are provided by 170 Bayard-Alpert gauges and 1084 gauges (Pirani and cold cathode Penning). The cryogenic insulation vacuums while technically less demanding, impress by their size (50 km) and volume (15000 m3). Once roughed using mechanical pumps, the vacuum relies on the cryopumping which allows reaching pressure in the 10-4 Pa range.

  8. Late secondary porosity associated with overpressure leak-off: Evidence from the Fulmar Formation, central North Sea

    SciTech Connect

    Darby, D.; Wilkinson, M.; Haszeldine, S. )

    1996-01-01

    The Upper Jurassic Fulmar sandstone of the Central North Sea is characterized by deep burial (greater than 4000m burial depth) and extremely high levels of overpressure (up to 40MPa overpressure at 4500m depth). High overpressure may support high porosity at great depths, and so the relationship between overpressure and porosity is of considerable commercial importance in deep prospects. Simulating the porosity evolution and overpressure of the sandstones via a two-dimensional basin model reveals that for the majority of Fulmar Fm. sandstones, the porosity evolution is a simple pattern of reduction during burial to present-day values of 15-20%. However, in wells sited close to structurally-elevated overpressure leak-off points, the porosity is anomalously high (up to 35% at 4500m depth). We suggest that pressure-induced vertical fluid flow at over-pressure leak points allows removal of the products of feldspar dissolution. This process allows porosity to increase from an end-Miocene low of 15-20% to the present-day values of 30-35%. Developing voids require support by overpressure, and so this increase in porosity must have occurred as the sandstones became highly over-pressured during rapid Plio-Pleistocene subsidence. We infer that overpressured sandstones may behave as open geochemical systems, and that 10-15% porosity has formed in regions of the Central Graben during deep burial in the last 5 Ma.

  9. Late secondary porosity associated with overpressure leak-off: Evidence from the Fulmar Formation, central North Sea

    SciTech Connect

    Darby, D.; Wilkinson, M.; Haszeldine, S.

    1996-12-31

    The Upper Jurassic Fulmar sandstone of the Central North Sea is characterized by deep burial (greater than 4000m burial depth) and extremely high levels of overpressure (up to 40MPa overpressure at 4500m depth). High overpressure may support high porosity at great depths, and so the relationship between overpressure and porosity is of considerable commercial importance in deep prospects. Simulating the porosity evolution and overpressure of the sandstones via a two-dimensional basin model reveals that for the majority of Fulmar Fm. sandstones, the porosity evolution is a simple pattern of reduction during burial to present-day values of 15-20%. However, in wells sited close to structurally-elevated overpressure leak-off points, the porosity is anomalously high (up to 35% at 4500m depth). We suggest that pressure-induced vertical fluid flow at over-pressure leak points allows removal of the products of feldspar dissolution. This process allows porosity to increase from an end-Miocene low of 15-20% to the present-day values of 30-35%. Developing voids require support by overpressure, and so this increase in porosity must have occurred as the sandstones became highly over-pressured during rapid Plio-Pleistocene subsidence. We infer that overpressured sandstones may behave as open geochemical systems, and that 10-15% porosity has formed in regions of the Central Graben during deep burial in the last 5 Ma.

  10. Vacuum aperture isolator for retroreflection from laser-irradiated target

    DOEpatents

    Benjamin, Robert F.; Mitchell, Kenneth B.

    1980-01-01

    The disclosure is directed to a vacuum aperture isolator for retroreflection of a laser-irradiated target. Within a vacuum chamber are disposed a beam focusing element, a disc having an aperture and a recollimating element. The edge of the focused beam impinges on the edge of the aperture to produce a plasma which refracts any retroreflected light from the laser's target.

  11. PLASMA WINDOW FOR VACUUM - ATMOSPHERE INTERFACE AND FOCUSING LENS OF SOURCES FOR NON-VACUUM MATERIAL MODIFICATION.

    SciTech Connect

    HERSHCOVITCH,A.

    1997-09-07

    Material modifications by ion implantation, dry etching, and micro-fabrication are widely used technologies, all of which are performed in vacuum, since ion beams at energies used in these applications are completely attenuated by foils or by long differentially pumped sections, which ate currently used to interface between vacuum and atmosphere. A novel plasma window, which utilizes a short arc for vacuum-atmosphere interface has been developed. This window provides for sufficient vacuum atmosphere separation, as well as for ion beam propagation through it, thus facilitating non-vacuum ion material modification.

  12. Fluid pressures in overpressured Forbes Formation, Sacramento Valley, California

    SciTech Connect

    Price, C.A.

    1988-03-01

    Initial shut-in pressures obtained from drill-stem tests, mud weights, and shale-compaction data were used to determine the formation fluid-pressure distribution in the southern Grimes gas field. Initial shut-in pressures in overpressured gas-bearing Forbes sandstones range from 3252 to 6660 psi. Pressure gradients range from 0.446 to 0.745 psi/ft. Regional initial shut-in pressure data suggest that (1) pressures appear to increase dramatically at approximately 7700 ft (2339 m) below sea level, (2) pressures generally increase with depth above 8200 ft (2491 m), but are highly variable below 8200 ft, and (3) the approximate depth to the top of geopressures is 5500 ft (1671 m) below sea level. Fluid pressures generally decrease from northeast to southwest through the region and from north to south within the westernmost fault block. Mud-weight data give maximum pressures for any depth. The maximum possible pressure gradient in the southern Grimes gas field is 0.847 psi/ft. The relationship between initial shut-in pressure and the amount of gas tested during drill-stem tests was also examined. More than 3000 MCFGD was tested only where the fluid pressure gradient was between 0.510 and 0.700 psi/ft. Twice as many drill-stem tests showed little or no gas when the fluid-pressure gradient exceeded 0.700 psi/ft than when it was less than 0.700 psi/ft. Fluid-pressure gradients greater than 0.700 psi/ft were encountered only below 8000 ft (2430 m); therefore, the probability of testing, and possibly producing, 3000 MCFGD decreases below 8000 ft.

  13. Fluid overpressure estimates from the aspect ratios of mineral veins

    NASA Astrophysics Data System (ADS)

    Philipp, Sonja L.

    2012-12-01

    Several hundred calcite veins and (mostly) normal faults were studied in limestone and shale layers of a Mesozoic sedimentary basin next to the village of Kilve at the Bristol Channel (SW-England). The veins strike mostly E-W (239 measurements), that is, parallel with the associated normal faults. The mean vein dip is 73°N (44 measurements). Field observations indicate that these faults transported the fluids up into the limestone layers. The vein outcrop (trace) length (0.025-10.3 m) and thickness (0.1-28 mm) size distributions are log-normal. Taking the thickness as the dependent variable and the outcrop length as the independent variable, linear regression gives a coefficient of determination (goodness of fit) of R2 = 0.74 (significant with 99% confidence), but natural logarithmic transformation of the thickness-length data increases the coefficient of determination to R2 = 0.98, indicating that nearly all the variation in thickness can be explained in terms of variation in trace length. The geometric mean of the aspect (length/thickness) ratio, 451, gives the best representation of the data set. With 95% confidence, the true geometric mean of the aspect ratios of the veins lies in the interval 409-497. Using elastic crack theory, appropriate elastic properties of the host rock, and the mean aspect ratio, the fluid overpressure (that is, the total fluid pressure minus the normal stress on the fracture plane) at the time of vein formation is estimated at around 18 MPa. From these results, and using the average host rock and water densities, the depth to the sources of the fluids (below the present exposures) forming the veins is estimated at between around 300 m and 1200 m. These results are in agreement to those obtained by independent isotopic studies and indicate that the fluids were of rather local origin, probably injected from sill-like sources (water sills) inside the sedimentary basin.

  14. Laser Vacuum Furnace for Zone Refining

    NASA Technical Reports Server (NTRS)

    Griner, D. B.; Zurburg, F. W.; Penn, W. M.

    1986-01-01

    Laser beam scanned to produce moving melt zone. Experimental laser vacuum furnace scans crystalline wafer with high-power CO2-laser beam to generate precise melt zone with precise control of temperature gradients around zone. Intended for zone refining of silicon or other semiconductors in low gravity, apparatus used in normal gravity.

  15. Technical specification for vacuum systems

    SciTech Connect

    Khaw, J.

    1987-01-01

    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 and 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)

  16. Use of overpressure to assess the role of bubbles in focused ultrasound lesion shape in vitro.

    PubMed

    Bailey, M R; Couret, L N; Sapozhnikov, O A; Khokhlova, V A; ter Haar, G; Vaezy, S; Shi, X; Martin, R; Crum, L A

    2001-05-01

    Overpressure--elevated hydrostatic pressure--was used to assess the role of gas or vapor bubbles in distorting the shape and position of a high-intensity focused ultrasound (HIFU) lesion in tissue. The shift from a cigar-shaped lesion to a tadpole-shaped lesion can mean that the wrong area is treated. Overpressure minimizes bubbles and bubble activity by dissolving gas bubbles, restricting bubble oscillation and raising the boiling temperature. Therefore, comparison with and without overpressure is a tool to assess the role of bubbles. Dissolution rates, bubble dynamics and boiling temperatures were determined as functions of pressure. Experiments were made first in a low-overpressure chamber (0.7 MPa maximum) that permitted imaging by B-mode ultrasound (US). Pieces of excised beef liver (8 cm thick) were treated in the chamber with 3.5 MHz for 1 to 7 s (50% duty cycle). In situ intensities (I(SP)) were 600 to 3000 W/cm(2). B-mode US imaging detected a hyperechoic region at the HIFU treatment site. The dissipation of this hyperechoic region following HIFU cessation corresponded well with calculated bubble dissolution rates; thus, suggesting that bubbles were present. Lesion shape was then tested in a high-pressure chamber. Intensities were 1300 and 1750 W/cm(2) ( +/- 20%) at 1 MHz for 30 s. Hydrostatic pressures were 0.1 or 5.6 MPa. At 1300 W/cm(2), lesions were cigar-shaped, and no difference was observed between lesions formed with or without overpressure. At 1750 W/cm(2), lesions formed with no overpressure were tadpole-shaped, but lesions formed with high overpressure (5.6 MPa) remained cigar-shaped. Data support the hypothesis that bubbles contribute to the lesion distortion.

  17. Structural levels of deformation and failure of heat-resistant 12Cr1MoV steel modified by vacuum arc treatment by Zr{sup +} ion beam

    SciTech Connect

    Vlasov, I. V. E-mail: svp@ispms.tsc.ru; Panin, S. V. E-mail: svp@ispms.tsc.ru; Ovechkin, B. B.; Sergeev, V. P.

    2014-11-14

    Study of structural changes occurring in the surface layer modified by ion-beam irradiation was carried out by means of optical, scanning and transmission electron microscopy. It was shown that irradiation induces the structure modification not only in the surface layer, but along the entire cross section of 1 mm thick specimens. It was elucidated that the complex pattern of structural changes is responsible for the pronounced variation of mechanical properties taking place under static tension and cyclic alternating bending.

  18. A study of sonic boom overpressure trends with respect to weight, altitude, Mach number, and vehicle shaping

    NASA Technical Reports Server (NTRS)

    Needleman, Kathy E.; Mack, Robert J.

    1990-01-01

    This paper presents and discusses trends in nose shock overpressure generated by two conceptual Mach 2.0 configurations. One configuration was designed for high aerodynamic efficiency, while the other was designed to produce a low boom, shaped-overpressure signature. Aerodynamic lift, sonic boom minimization, and Mach-sliced/area-rule codes were used to analyze and compute the sonic boom characteristics of both configurations with respect to cruise Mach number, weight, and altitude. The influence of these parameters on the overpressure and the overpressure trends are discussed and conclusions are given.

  19. Suprathermal electrons in a vacuum spark discharge

    SciTech Connect

    Bashutin, O. A. Savjolov, A. S.

    2016-04-15

    Results of experiments on the detection of suprathermal electron beams in the plasma of a highcurrent low-inductance vacuum spark by means of space-resolved spectral X-ray polarimetry are presented. It is shown that the observed polarization of bremsstrahlung may be caused by an ~100-keV electron beam propagating along the discharge axis from the pinching region toward the anode. The influence of the discharge initiation conditions on the parameters of the generated electron beams is analyzed.

  20. Development of space shuttle ignition overpressure environment and correlation with flight data

    NASA Technical Reports Server (NTRS)

    Lai, S.

    1983-01-01

    The Space Transportation (STS) launch vehicles are more complex than other launch vehicles. A comprehensive analysis of the lift-off event is required so that the responses of the vehicle and payloads can be predicted. The transient overpressure induced by ignition of the solid rocket motors (SRM's) is one of the critical design factors assessed for lift-off. The STS-1 ignition overpressure design environment was developed from 6.4-percent scale-model tests in which the Tomahawk solid rocket motors were used to simulate the start-up process of the SRM's. The overpressures measured during STS-1 lift-off were much more severe than predicted. The reasons for this anomaly are discussed in this paper. The 6.4-percent scale model was redesigned and used as a tool to develop an effective ignition overpressure suppression system for STS-2 and subsequent flights. Also presented are advancements in subscale-model simulation and theoretical understanding of this transient overpressure phenomenon that led to the successful development of the fix.

  1. Pore pressure estimation from velocity data: Accounting for overpressure mechanisms besides undercompaction

    SciTech Connect

    Bowers, G.L.

    1995-06-01

    A new method for estimating pore pressure from formation sonic velocity data is presented. Unlike previous techniques, this method accounts for excess pressure generated by both undercompaction, and fluid expansion mechanisms such as aquathermal pressuring, hydrocarbon maturation, clay diagenesis, and charging from other zones. The method is an effective stress approach; the effective stress is computed from the velocity, and the result is subtracted from the overburden stress to obtain pore pressure. to include multiple sources of overpressure, a pair of velocity-vs.-effective-stress relations are introduced. One relation accounts for normal pressure and overpressure caused by undercompaction. The second is applied inside velocity reversal zones caused by fluid expansion mechanisms. Example applications of the method are presented from the U.S. gulf coast, the Gulf of Mexico, and the Central North Sea. some other pore pressure estimation approaches are also examined to demonstrate how these techniques have unknowingly accounted for overpressure mechanisms other than undercompaction. It is also explained how velocity-vs.-effective-stress data can be used to identify the general cause of overpressure in an area. For instance, the empirical correlation of Hottman and Johnson indicates that overpressure along the US gulf coast cannot be due only to undercompaction.

  2. Effect of overpressure and pulse repetition frequency on cavitation in shock wave lithotripsy.

    PubMed

    Sapozhnikov, Oleg A; Khokhlova, Vera A; Bailey, Michael R; Williams, James C; McAteer, James A; Cleveland, Robin O; Crum, Lawrence A

    2002-09-01

    Cavitation appears to contribute to tissue injury in lithotripsy. Reports have shown that increasing pulse repetition frequency [(PRF) 0.5-100 Hz] increases tissue damage and increasing static pressure (1-3 bar) reduces cell damage without decreasing stone comminution. Our hypothesis is that overpressure or slow PRF causes unstabilized bubbles produced by one shock pulse to dissolve before they nucleate cavitation by subsequent shock pulses. The effects of PRF and overpressure on bubble dynamics and lifetimes were studied experimentally with passive cavitation detection, high-speed photography, and B-mode ultrasound and theoretically. Overpressure significantly reduced calculated (100-2 s) and measured (55-0.5 s) bubble lifetimes. At 1.5 bar static pressure, a dense bubble cluster was measured with clinically high PRF (2-3 Hz) and a sparse cluster with clinically low PRF (0.5-1 Hz), indicating bubble lifetimes of 0.5-1 s, consistent with calculations. In contrast to cavitation in water, high-speed photography showed that overpressure did not suppress cavitation of bubbles stabilized on a cracked surface. These results suggest that a judicious use of overpressure and PRF in lithotripsy could reduce cavitation damage of tissue while maintaining cavitation comminution of stones.

  3. Rapid sedimentation and overpressure in shallow sediments of the Bering Trough, offshore southern Alaska

    NASA Astrophysics Data System (ADS)

    Daigle, Hugh; Worthington, Lindsay L.; Gulick, Sean P. S.; Van Avendonk, Harm J. A.

    2017-04-01

    Pore pressures in sediments at convergent margins play an important role in driving chemical fluxes and controlling deformation styles and localization. In the Bering Trough offshore Southern Alaska, extreme sedimentation rates over the last 140 kyr as a result of glacial advance/retreats on the continental shelf have resulted in elevated pore fluid pressures in slope sediments overlying the Pamplona Zone fold and thrust belt, the accretionary wedge resulting from subduction of the Yakutat microplate beneath the North American Plate. Based on laboratory experiments and downhole logs acquired at Integrated Ocean Drilling Program Site U1421, we predict that the overpressure in the slope sediments may be as high as 92% of the lithostatic stress. Results of one-dimensional numerical modeling accounting for changes in sedimentation rate over the last 130 kyr predicted overpressures that are consistent with our estimates, suggesting that the overpressure is a direct result of the rapid sedimentation experienced on the Bering shelf and slope. Comparisons with other convergent margins indicate that such rapid sedimentation and high overpressure are anomalous in sediments overlying accretionary wedges. We hypothesize that the shallow overpressure on the Bering shelf/slope has fundamentally altered the deformation style within the Pamplona Zone by suppressing development of faults and may inhibit seismicity by focusing faulting elsewhere or causing deformation on existing faults to be aseismic. These consequences are probably long-lived as it may take several million years for the excess pressure to dissipate.

  4. Investigation on the relationship between overpressure and sub-harmonic response from encapsulated microbubbles

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Fan, Ting-Bo; Xu, Di; Zhang, Dong

    2014-10-01

    Sub-harmonic component generated from microbubbles is proven to be potentially used in noninvasive blood pressure measurement. Both theoretical and experimental studies are performed in the present work to investigate the dependence of the sub-harmonic generation on the overpressure with different excitation pressure amplitudes and pulse lengths. With 4-MHz ultrasound excitation at an applied acoustic pressure amplitude of 0.24 MPa, the measured sub-harmonic amplitude exhibits a decreasing change as overpressure increases; while non-monotonic change is observed for the applied acoustic pressures of 0.36 MPa and 0.48 MPa, and the peak position in the curve of the sub-harmonic response versus the overpressure shifts toward higher overpressure as the excitation pressure amplitude increases. Furthermore, the exciting pulse with long duration could lead to a better sensitivity of the sub-harmonic response to overpressure. The measured results are explained by the numerical simulations based on the Marmottant model. The numerical simulations qualitatively accord with the measured results. This work might provide a preliminary proof for the optimization of the noninvasive blood pressure measurement through using sub-harmonic generation from microbubbles.

  5. Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

    SciTech Connect

    Hussain, Z.

    1995-08-01

    The purpose of this document is to: (1) Explain the ALS vacuum policy and specifications for beamlines and experiment endstations. (2) Provide guidelines related to ALS vacuum policy to assist in designing beamlines which are in accordance with ALS vacuum policy. This document supersedes LSBL-116. The Advanced Light Source is a third generation synchrotron radiation source whose beam lifetime depends on the quality of the vacuum in the storage ring and the connecting beamlines. The storage ring and most of the beamlines share a common vacuum and are operated under ultra-high-vacuum (UHV) conditions. All endstations and beamline equipment must be operated so as to avoid contamination of beamline components, and must include proper safeguards to protect the storage ring vacuum from an accidental break in the beamline or endstation vacuum systems. The primary gas load during operation is due to thermal desorption and electron/photon induced desorption of contaminants from the interior of the vacuum vessel and its components. The desorption rates are considerably higher for hydrocarbon contamination, thus considerable emphasis is placed on eliminating these sources of contaminants. All vacuum components in a beamline and endstation must meet the ALS vacuum specifications. The vacuum design of both beamlines and endstations must be approved by the ALS Beamline Review Committee (BRC) before vacuum connections to the storage ring are made. The vacuum design is first checked during the Beamline Design Review (BDR) held before construction of the beamline equipment begins. Any deviation from the ALS vacuum specifications must be approved by the BRC prior to installation of the equipment on the ALS floor. Any modification that is incorporated into a vacuum assembly without the written approval of the BRC is done at the user`s risk and may lead to rejection of the whole assembly.

  6. Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet (VUV) synchrotron ionization quadrupole mass spectrometry: Application to low--temperature kinetics and product detection

    SciTech Connect

    Soorkia, Satchin; Liu, Chen-Lin; Savee, John D; Ferrell, Sarah J; Leone, Stephen R; Wilson, Kevin R

    2011-10-12

    A new pulsed Laval nozzle apparatus with vacuum ultraviolet (VUV) synchrotron photoionization quadrupole mass spectrometry is constructed to study low-temperature radicalneutralchemical reactions of importance for modeling the atmosphere of Titan and the outer planets. A design for the sampling geometry of a pulsed Laval nozzle expansion has beendeveloped that operates successfully for the determination of rate coefficients by time-resolved mass spectrometry. The new concept employs airfoil sampling of the collimated expansion withexcellent sampling throughput. Time-resolved profiles of the high Mach number gas flow obtained by photoionization signals show that perturbation of the collimated expansion by theairfoil is negligible. The reaction of C2H with C2H2 is studied at 70 K as a proof-of-principle result for both low-temperature rate coefficient measurements and product identification basedon the photoionization spectrum of the reaction product versus VUV photon energy. This approach can be used to provide new insights into reaction mechanisms occurring at kinetic ratesclose to the collision-determined limit.

  7. Beam diagnostics

    SciTech Connect

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-08-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the {open_quotes}Booster{close_quotes} and {open_quotes}ATLAS{close_quotes} linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates.

  8. Final focus test beam

    SciTech Connect

    Not Available

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  9. Vacuum phenomenon.

    PubMed

    Yanagawa, Youichi; Ohsaka, Hiromichi; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Omori, Kazuhiko; Oode, Yasumasa; Ishikawa, Kouhei

    2016-08-01

    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  10. Degradation of the lunar vacuum by a moon base

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey

    1990-01-01

    Several industrial processes requiring high and ultra-high vacuum similar to the lunar vacuum are outlined. The effects of a 20-person lunar base and a 250-person industrial facility on this vacuum are discussed. It is shown that exhaust from transport spacecraft and leakage from the habitat will be comparable to the daytime gas pressure for the 20-person base, and will degrade the vacuum to the range of 2 x 10 to the -9th torr for the use of 250-person facility. This will result in replacing the mostly nonreactive gases hydrogen, helium, and neon with more reactive gases containing carbon and oxygen. This vacuum is still good enough to perform many important vacuum processes such as plasma-deposition of amorphous silicon for solar cells, but processes such as molecular beam epitaxy or locating an intersecting beam accelerator on the moon will require additional vacuum pumping.

  11. Degradation of the lunar vacuum by a moon base

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey

    1990-01-01

    Several industrial processes requiring high and ultra-high vacuum similar to the lunar vacuum are outlined. The effects of a 20-person lunar base and a 250-person industrial facility on this vacuum are discussed. It is shown that exhaust from transport spacecraft and leakage from the habitat will be comparable to the daytime gas pressure for the 20-person base, and will degrade the vacuum to the range of 2 x 10 to the -9th torr for the use of 250-person facility. This will result in replacing the mostly nonreactive gases hydrogen, helium, and neon with more reactive gases containing carbon and oxygen. This vacuum is still good enough to perform many important vacuum processes such as plasma-deposition of amorphous silicon for solar cells, but processes such as molecular beam epitaxy or locating an intersecting beam accelerator on the moon will require additional vacuum pumping.

  12. Degradation of the lunar vacuum by a moon base

    NASA Astrophysics Data System (ADS)

    Landis, G. A.

    1990-03-01

    Several industrial processes requiring high and ultra-high vacuum similar to the lunar vacuum are outlined. The effects of a 20-person lunar base and a 250-person industrial facility on this vacuum are discussed. It is shown that exhaust from transport spacecraft and leakage from the habitat will be comparable to the daytime gas pressure for the 20-person base, and will degrade the vacuum to the range of 2 x 10 to the -9th torr for the use of 250-person facility. This will result in replacing the mostly nonreactive gases hydrogen, helium, and neon with more reactive gases containing carbon and oxygen. This vacuum is still good enough to perform many important vacuum processes such as plasma-deposition of amorphous silicon for solar cells, but processes such as molecular beam epitaxy or locating an intersecting beam accelerator on the moon will require additional vacuum pumping.

  13. Impact of copper overpressure on the synthesis of hexagonal boron nitride atomic layers.

    PubMed

    Bresnehan, Michael S; Bhimanapati, Ganesh R; Wang, Ke; Snyder, David W; Robinson, Joshua A

    2014-10-08

    Hexagonal boron nitride (h-BN) atomic layers are synthesized on polycrystalline copper foils via a novel chemical vapor deposition (CVD) process that maintains a vapor-phase copper overpressure during growth. Compared to h-BN films grown without a copper overpressure, this process results in a >10× reduction of 3-dimensional BN fullerene-like surface features, a reduction of carbon and oxygen contamination of 65% and 62%, respectively, an increase in h-BN grain size of >2×, and an 89% increase in electrical breakdown strength.

  14. Electron beam focusing system

    SciTech Connect

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  15. 46 CFR 39.6003 - Overpressure and underpressure protection during stripping or gas-freeing operations-B/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Overpressure and underpressure protection during stripping or gas-freeing operations-B/ALL. 39.6003 Section 39.6003 Shipping COAST GUARD, DEPARTMENT OF... § 39.6003 Overpressure and underpressure protection during stripping or gas-freeing operations—B/ALL...

  16. 46 CFR 39.6003 - Overpressure and underpressure protection during stripping or gas-freeing operations-B/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Overpressure and underpressure protection during stripping or gas-freeing operations-B/ALL. 39.6003 Section 39.6003 Shipping COAST GUARD, DEPARTMENT OF... § 39.6003 Overpressure and underpressure protection during stripping or gas-freeing operations—B/ALL...

  17. Vacuum isostatic micro/macro molding of PTFE materials for laser beam shaping in environmental applications: large scale UV laser water purification

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd; Ohar, Orest

    2009-08-01

    Accessibility to fresh clean water has determined the location and survival of civilizations throughout the ages [1]. The tangible economic value of water is demonstrated by industry's need for water in fields such as semiconductor, food and pharmaceutical manufacturing. Economic stability for all sectors of industry depends on access to reliable volumes of good quality water. As can be seen on television a nation's economy is seriously affected by water shortages through drought or mismanagement and as such those water resources must therefore be managed both for the public interest and the economic future. For over 50 years ultraviolet water purification has been the mainstay technology for water treatment, killing potential microbiological agents in water for leisure activities such as swimming pools to large scale waste water treatment facilities where the UV light photo-oxidizes various pollutants and contaminants. Well tailored to the task, UV provides a cost effective way to reduce the use of chemicals in sanitization and anti-biological applications. Predominantly based on low pressure Hg UV discharge lamps, the system is plagued with lifetime issues (~1 year normal operation), the last ten years has shown that the technology continues to advance and larger scale systems are turning to more advanced lamp designs and evaluating solidstate UV light sources and more powerful laser sources. One of the issues facing the treatment of water with UV lasers is an appropriate means of delivering laser light efficiently over larger volumes or cross sections of water. This paper examines the potential advantages of laser beam shaping components made from isostatically micro molding microstructured PTFE materials for integration into large scale water purification and sterilization systems, for both lamps and laser sources. Applying a unique patented fabrication method engineers can form micro and macro scale diffractive, holographic and faceted reflective structures

  18. Detecting structural variances of Co3O4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope.

    PubMed

    Kisielowski, C; Frei, H; Specht, P; Sharp, I D; Haber, J A; Helveg, S

    2017-01-01

    This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co3O4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Å(2)s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co3O4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. An exposure of the Co3O4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner.

  19. Rotational state selection of a CH3I+ ion beam using vacuum ultraviolet-mass-analyzed threshold ionization spectroscopy: Characterization using photodissociation spectroscopy

    NASA Astrophysics Data System (ADS)

    Bae, Yong Jin; Kim, Myung Soo

    2008-03-01

    The ÃA12←X˜E3/22 transition of CH3I + was investigated by photodissociation (PD) of the cation generated by one-photon mass-analyzed threshold ionization (MATI). Compared to the PD spectrum obtained by excitation of the cation in the main 0-0 band in the MATI spectrum, those obtained by excitation of the cations in the satellite structures showed substantially simplified rotational structures for nondegenerate vibronic bands. Spectral simplification occurred because each satellite consisted mostly of cations with one K quantum number. Spectroscopic constants in the ground vibronic state and in the 2135, 2138, 39, and 313 nondegenerate vibrational states in ÃA12 were determined via spectral fitting. Also, those in the 213n61 (n=1?) degenerate state, which had been reported previously, was improved. The K quantum number in each satellite determined by the present high resolution study was compatible with the prediction by the symmetry selection rule for photoionization. That is, the K quantum number of the ion core in high Rydberg states accessed by one-photon excitation was found to be conserved upon pulsed field ionization. This work demonstrates generation of mass-selected, vibronically selected, and K-selected ion beam by one-photon MATI.

  20. Detecting structural variances of Co3O4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope

    DOE PAGES

    Kisielowski, C.; Frei, H.; Specht, P.; ...

    2016-11-02

    This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co3O4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Å2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Thresholdmore » doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co3O4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. Finallly, an exposure of the Co3O4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner.« less

  1. Two-color bright squeezed vacuum

    SciTech Connect

    Agafonov, Ivan N.; Chekhova, Maria V.

    2010-07-15

    In a strongly pumped nondegenerate traveling-wave optical parametric amplifier, we produce a two-color squeezed vacuum with up to millions of photons per pulse. Our approach to registering this macroscopic quantum state is direct detection of a large number of transverse and longitudinal modes, which is achieved by making the detection time and area much larger than the coherence time and area, respectively. Using this approach, we obtain a record value of twin-beam squeezing for direct detection of bright squeezed vacuum. This makes direct detection of macroscopic squeezed vacuum a practical tool for quantum information applications.

  2. Vacuum mechatronics. Proceedings.

    NASA Astrophysics Data System (ADS)

    Belinski, S. E.; Shirazi, M.; Hackwood, S.; Beni, G.

    The discipline of vacuum mechatronics is the design and development of vacuum-compatible, computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. Vacuum mechantronics is relevant to research engineers in integrated circuit manufacturing, surface physics, food processing, biotechnology, materials handling, space sciences and manufacturing.

  3. Overpressure, Flow Focusing, Compaction and Slope Stability on the continental slope: Insights from IODP Expedition 308

    NASA Astrophysics Data System (ADS)

    Flemings, P. B.

    2010-12-01

    Integrated Ocean Drilling Program Expepedition 308 used direct measurements of pore pressure, analysis of hydromechanical properties, and geological analysis to illuminate how sedimentation, flow focusing, overpressure, and slope stability couple beneath the seafloor on the deepwater continental slope in the Gulf of Mexico. We used pore pressure penetrometers to measure severe overpressures (60% of the difference between lithostatic stress and hydrostatic pressure) that extend from the seafloor for 100’s of meters. We ran uniaxial consolidation experiments on whole core and found that although permeability is relatively high near the seafloor, the sediments are highly compressible. As a result, the coefficient of consolidation (the hydraulic diffusivity) is remarkably constant over a large range of effective stresses. This behavior accounts for the high overpressure that begins near the seafloor and extends to depth. Forward modeling suggests that flow is driven laterally along a permeable unit called the Blue Unit. Calculations suggest that soon after deposition, lateral flow lowered the effective stress and triggered the submarine landslides that we observe. Later in the evolution of this system, overpressure may have pre-conditioned the slope to failure by earthquakes. Results from IODP Expedition 308 illustrate how pore pressure and sedimentation control the large-scale form of continental margins, how submarine landslides form, and provide strategies for designing stable drilling programs.

  4. 5 Percent Ares I Scale Model Acoustic Test: Overpressure Characterization and Analysis

    NASA Technical Reports Server (NTRS)

    Alvord, David; Casiano, Matthew; McDaniels, Dave

    2011-01-01

    During the ignition of a ducted solid rocket motor (SRM), rapid expansion of injected hot gases from the motor into a confined volume causes the development of a steep fronted wave. This low frequency transient wave propagates outward from the exhaust duct, impinging the vehicle and ground structures. An unsuppressed overpressure wave can potentially cause modal excitation in the structures and vehicle, subsequently leading to damage. This presentation details the ignition transient f indings from the 5% Ares I Scale Model Acoustic Test (ASMAT). The primary events of the ignition transient environment induced by the SRM are the ignition overpressure (IOP), duct overpressure (DOP), and source overpressure (SOP). The resulting observations include successful knockdown of the IOP environment through use of a Space Shuttle derived IOP suppression system, a potential load applied to the vehicle stemming from instantaneous asymmetrical IOP and DOP wave impingement, and launch complex geometric influences on the environment. The results are scaled to a full-scale Ares I equivalent and compared with heritage data including Ares I-X and both suppressed and unsuppressed Space Shuttle IOP environments.

  5. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION...

  6. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION...

  7. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION...

  8. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... explosions resulting from debris impacts, including the potential for mixing of liquid propellants; (4... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Far-field overpressure blast effects analysis. 417.229 Section 417.229 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION...

  9. Thermodynamic and hydrodynamic constraints on overpressure caused by hydrate dissociation: A pore-scale model

    NASA Astrophysics Data System (ADS)

    Holtzman, R.; Juanes, R.

    2011-07-01

    It has been suggested that volume expansion caused by hydrate dissociation in sediment pores can result in large overpressure, which in turn may destabilize the sediment and trigger massive submarine landslides. Here, we investigate the pressure evolution during thermally-induced dissociation, by means of a pore-scale model that couples dissociation kinetics, multiphase flow and geomechanics. Dissociation is controlled by a self-preservation mechanism: increasing pore pressure reduces the driving force for dissociation. Hence, the overpressure is constrained by the phase equilibrium pressure, regardless of the kinetic rate of dissociation, heat supply, and sediment permeability. Furthermore, we find that the timescale for buildup of pressure by dissociation is typically much larger than that for its dissipation by drainage. Consequently, the overpressure is controlled by the capillary entry thresholds, which depend on the mode of gas invasion. In low-permeability systems, fracturing is the preferred mechanism, occurring at capillary pressures lower than the entry thresholds in the undeformed sediment. Our results suggest that while large overpressures cannot be sustained by rapid dissociation in natural systems, dissociation can induce important geomechanical effects. Gas migration by fracturing provides a possible link between dissociation, sediment deformation and methane venting.

  10. An analysis of the response of Sooty Tern eggs to sonic boom overpressures.

    PubMed

    Ting, Carina; Garrelick, Joel; Bowles, Ann

    2002-01-01

    It has been proposed that sonic booms caused a mass hatching failure of Sooty Terns in the Dry Tortugas in Florida by cracking the eggshells. This paper investigates this possibility analytically, complementing previous empirical studies. The sonic boom is represented as a plane-wave excitation with an N-wave time signature. Two models for the egg are employed. The first model, intended to provide insight, consists of a spherical shell, with the embryo represented as a rigid, concentric sphere and the albumen as an acoustic fluid filling the intervening volume. The substrate is modeled as a doubling of the incident pressure. The second, numerical model includes the egg-shape geometry and air sac. More importantly, the substrate is modeled as a rigid boundary of infinite extent with acoustic diffraction included. The peak shell stress, embryo acceleration, and reactive force are predicted as a function of the peak sonic boom overpressure and compared with damage criteria from the literature. The predicted peak sonic boom overpressure necessary for egg damage is much higher than documented sonic boom overpressures, even for extraordinary operational conditions. Therefore, as with previous empirical studies, it is concluded that it is unlikely that sonic boom overpressures damage avian eggs.

  11. An analysis of the response of Sooty Tern eggs to sonic boom overpressures

    NASA Astrophysics Data System (ADS)

    Ting, Carina; Garrelick, Joel; Bowles, Ann

    2002-01-01

    It has been proposed that sonic booms caused a mass hatching failure of Sooty Terns in the Dry Tortugas in Florida by cracking the eggshells. This paper investigates this possibility analytically, complementing previous empirical studies. The sonic boom is represented as a plane-wave excitation with an N-wave time signature. Two models for the egg are employed. The first model, intended to provide insight, consists of a spherical shell, with the embryo represented as a rigid, concentric sphere and the albumen as an acoustic fluid filling the intervening volume. The substrate is modeled as a doubling of the incident pressure. The second, numerical model includes the egg-shape geometry and air sac. More importantly, the substrate is modeled as a rigid boundary of infinite extent with acoustic diffraction included. The peak shell stress, embryo acceleration, and reactive force are predicted as a function of the peak sonic boom overpressure and compared with damage criteria from the literature. The predicted peak sonic boom overpressure necessary for egg damage is much higher than documented sonic boom overpressures, even for extraordinary operational conditions. Therefore, as with previous empirical studies, it is concluded that it is unlikely that sonic boom overpressures damage avian eggs.

  12. Up-regulation of reactivity and survival genes in astrocytes after exposure to short duration overpressure.

    PubMed

    Vandevord, Pamela J; Leung, Lai Yee; Hardy, Warren; Mason, Matthew; Yang, King H; King, Albert I

    2008-04-04

    Gurdjian et al. proposed decades ago that pressure gradients played a major factor in neuronal injury due to impact. In the late 1950s, their experiments on concussion demonstrated that the principal factor in the production of concussion in animals was the sudden increase of intracranial pressure accompanying head injury. They reported the increase in pressure severity correlated with an increase in 'altered cells' resulting in animal death. More recently, Hardy et al. (2006) demonstrated the presence of transient pressure pulses with impact conditions. These studies indicate that short duration overpressure should be further examined as a mechanism of traumatic brain injury (TBI). In the present study, we designed and fabricated a barochamber that simulated overpressure noted in various head injury studies. We tested the effect of overpressure on astrocytes. Expressions of apoptotic, reactivity and survival genes were examined at 24, 48 and 72 h post-overpressure exposure. At 24 h, we found elevated levels of reactivity and survival gene expression. By 48 h, a decreased expression of apoptotic genes was demonstrated. This study reinforces the hypothesis that transient pressure acts to instigate the cellular response displayed following TBI.

  13. Prediction of sonic boom from experimental near-field overpressure data. Volume 2: Data base construction

    NASA Technical Reports Server (NTRS)

    Glatt, C. R.; Reiners, S. J.; Hague, D. S.

    1975-01-01

    A computerized method for storing, updating and augmenting experimentally determined overpressure signatures has been developed. A data base of pressure signatures for a shuttle type vehicle has been stored. The data base has been used for the prediction of sonic boom with the program described in Volume I.

  14. Antifungal metabolites from the roots of Diospyros virginiana by overpressure layer chromatography

    USDA-ARS?s Scientific Manuscript database

    A preparative overpressure layer chromatography (OPLC) method was successfully used for the separation of two new natural compounds, 4-hydroxy-5,6-dimethoxy-2-naphthaldehyde (1) and (Delta)12,13-20,29-dihydrobetulin (2) together with nine known compounds including 7-methyl-juglone (3), diospyrin (4)...

  15. 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.

  16. 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.

  17. 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.

  18. Evolution of overpressured and underpressured oil and gas reservoirs, Anadarko Basin of Oklahoma, Texas, and Kansas

    USGS Publications Warehouse

    Nelson, Phillip H.; Gianoutsos, Nicholas J.

    2011-01-01

    Departures of resistivity logs from a normal compaction gradient indicate that overpressure previously extended north of the present-day overpressured zone. These indicators of paleopressure, which are strongest in the deep basin, are mapped to the Kansas-Oklahoma border in shales of Desmoinesian age. The broad area of paleopressure has contracted to the deep basin, and today the overpressured deep basin, as determined from drillstem tests, is bounded on the north by strata with near normal pressures (hydrostatic), grading to the northwest to pressures that are less than hydrostatic (underpressured). Thus the pressure regime in the northwest portion of the Anadarko Basin has evolved from paleo-overpressure to present-day underpressure. Using pressure data from drillstem tests, we constructed cross sections and potentiometric maps that illustrate the extent and nature of present-day underpressuring. Downcutting and exposure of Lower Permian and Pennsylvanian strata along, and east of, the Nemaha fault zone in central Oklahoma form the discharge locus where pressure reaches near atmospheric. From east to west, hydraulic head increases by several hundred feet in each rock formation, whereas elevation increases by thousands of feet. The resulting underpressuring of the aquifer-supported oil and gas fields, which also increases from east to west, is a consequence of the vertical separation between surface elevation and hydraulic head. A 1,000-ft thick cap of Permian evaporites and shales isolates the underlying strata from the surface, preventing re-establishment of a normal hydrostatic gradient. Thus, the present-day pressure regime of oil and gas reservoirs, overpressured in the deep basin and underpressured on the northwest flank of the basin, is the result of two distinct geologic events-rapid burial and uplift/erosion-widely separated in time.

  19. Simulated blast overpressure induces specific astrocyte injury in an ex vivo brain slice model

    PubMed Central

    Canchi, Saranya; Sarntinoranont, Malisa; Hong, Yu; Flint, Jeremy J.; Subhash, Ghatu; King, Michael A.

    2017-01-01

    Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood–brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue. Using an ex vivo brain slice model, we tested the hypothesis that viable astrocytes within the slice could be injured simply by transit of a single blast wave consisting of overpressure alone. A polymer split Hopkinson pressure bar (PSHPB) system was adapted to impart a single positive pressure transient with a comparable magnitude to those that might be present inside the head. A custom built test chamber housing the brain tissue slice incorporated revised design elements to reduce fluid space and promote transit of a uniform planar waveform. Confocal microscopy, stereology, and morphometry of glial fibrillary acidic protein (GFAP) immunoreactivity revealed that two distinct astrocyte injury profiles were identified across a 4 hr post-test survival interval: (a) presumed conventional astrogliosis characterized by enhanced GFAP immunofluorescence intensity without significant change in tissue area fraction and (b) a process comparable to clasmatodendrosis, an autophagic degradation of distal processes that has not been previously associated with blast induced neurotrauma. Analysis of astrocyte branching revealed early, sustained, and progressive differences distinct from the effects of slice incubation absent overpressure testing. Astrocyte vulnerability to overpressure transients indicates a potential for significant involvement in brain blast pathology and emergent dysfunction. The testing platform can isolate overpressure injury

  20. Simulated blast overpressure induces specific astrocyte injury in an ex vivo brain slice model.

    PubMed

    Canchi, Saranya; Sarntinoranont, Malisa; Hong, Yu; Flint, Jeremy J; Subhash, Ghatu; King, Michael A

    2017-01-01

    Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood-brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue. Using an ex vivo brain slice model, we tested the hypothesis that viable astrocytes within the slice could be injured simply by transit of a single blast wave consisting of overpressure alone. A polymer split Hopkinson pressure bar (PSHPB) system was adapted to impart a single positive pressure transient with a comparable magnitude to those that might be present inside the head. A custom built test chamber housing the brain tissue slice incorporated revised design elements to reduce fluid space and promote transit of a uniform planar waveform. Confocal microscopy, stereology, and morphometry of glial fibrillary acidic protein (GFAP) immunoreactivity revealed that two distinct astrocyte injury profiles were identified across a 4 hr post-test survival interval: (a) presumed conventional astrogliosis characterized by enhanced GFAP immunofluorescence intensity without significant change in tissue area fraction and (b) a process comparable to clasmatodendrosis, an autophagic degradation of distal processes that has not been previously associated with blast induced neurotrauma. Analysis of astrocyte branching revealed early, sustained, and progressive differences distinct from the effects of slice incubation absent overpressure testing. Astrocyte vulnerability to overpressure transients indicates a potential for significant involvement in brain blast pathology and emergent dysfunction. The testing platform can isolate overpressure injury

  1. Seismic detection of overpressuring and fracturing: An example from the Qaidam Basin, People's Republic of China

    SciTech Connect

    Paul, R.J. )

    1993-10-01

    Shallow hydrocarbon reserves were discovered in 1959 in the Nan Yi Shan structure located near the western corner of the Qaidam Basin. The first successful deep well encountered an overpressured zone at 3,000 m that resulted in a well blowout. To improve the structural definition of the field and delineate the overpressured layer a 3-D seismic survey was conducted. A region of anomalous seismic time sag associated with fracturing and small quantities of oil and gas was identified on the northwest plunging nose of the Nan Yi Shan anticline. The distribution of stacking (NMO) velocities in this region was regarded as abnormal; stacking velocities derived on the steeply dipping flanks adjacent to the sag anomaly were found to be slower than those on the shallower crest. Ray-trace modeling of a buried low-velocity anomaly provided a possible geometric solution to explain both the time variant nature of the sag and the unusual stacking velocity signature associated with it. A significant difference in seismic and sonic travel times was also observed for wells that penetrated the sag region and was attributed to localized fracturing. In a deeper interval, seismic amplitudes were used to identify gas-saturated fracture porosity and to describe the spatial limits of overpressuring within a thin-bed reservoir. Wells drilled through high-amplitude anomalies encountered overpressuring, those drilled in a region of moderate seismic amplitude tested significant quantities of gas, and wells located outside the region of good coherent signal encountered poor or no hydrocarbon shows. These results demonstrate that with good quality seismic data and sufficient lateral and vertical resolution, thin fractured hydrocarbon-bearing reservoirs can be delineated and overpressure zones identified.

  2. Overpressure wave interaction with droplets: time resolved measurements by laser shadowscopy

    NASA Astrophysics Data System (ADS)

    Slangen, Pierre; Aprin, Laurent; Heymes, Frédéric; Munier, Laurent; Lapébie, Emmanuel; Dusserre, Gilles

    2012-10-01

    Risk sciences involve increasingly optics applications to perform accurate analysis of critical behavior such as failures, explosions, fires. In this particular context, different area sizes are investigated under high temporal sampling rate up to 10000fps. With the improvement of light sources and optical sensors, it is now possible to cope with high spatial resolution even for time resolved measurement. The paper deals with the study of the interaction between overpressure waves, occurring in case of explosion for example, with a liquid droplet present in the vicinity of the overpressure wave. This is a typical scenario encountered in case of industrial breakdown including liquid leakage and explosions. We designed an experimental setup for the evaluation of the interaction between the overpressure wave and falling liquid droplets. A gas chamber is filled with nitrogen until breakage of the outlet rupture disk at about 4 bar. The droplets fall is controlled by an automatic syringe injector placed in the overpressure wave. The imaging system is based on laser shadowscopy. The laser source is a double cavity 15mJ- 1000Hz Nd YLF laser emitting double pulses of about 10ns at 527nm. To record the double pulse after crossing the falling droplets, the transmitted light is captured by a lasersynchronized double frame camera. Since these measurements are time-synchronized, it is then possible to know accurately the different parameters of the phenomenon, such as overpressure wave velocity, droplets diameter, and Reynolds number. Different experiments have been carried out at about 4000 doubleframe/s. The paper presents the whole experiment, the enhancements of the setup and the results for different liquid products from water to acetone.

  3. Vacuum Melting of Refractory Metals and Alloys in Lining Furnaces (Chapter VI),

    DTIC Science & Technology

    Melting, *Refractory metals, *Refractory metal alloys, Vacuum furnaces, Linings, Electric arcs, Crucibles, Titanium alloys, Safety, Arc melting, Electron beam melting , Plasmas(Physics), Heating, Translations, USSR

  4. Mirror fusion vacuum technology developments

    SciTech Connect

    Batzer, T.H.; Call, W.R.

    1983-11-21

    Magnetic Mirror Fusion experiments, such as MFTF-B+T (Mirror Fusion Test Facility-B, Tritium Upgrade) and foreseeable follow-on devices, have operational and maintenance requirements that have not yet been fully demonstrated. Among those associated with vacuum technology are the very-high continuous-pumping speeds, 10/sup 7/ to 10/sup 8/ l/s for D/sub 2/, T/sub 2/ and, to a lesser extent, He; the early detection of water leaks from the very-high heat-flux neutral-beam dumps and the detection and location of leaks in the superconducting magnets not protected by guard vacuums. Possible solutions to these problems have been identified and considerable progress has been made toward successfully demonstrating their feasibility.

  5. Characteristic overpressure-impulse-distance curves for vapour cloud explosions using the TNO Multi-Energy model.

    PubMed

    Díaz Alonso, Fernando; González Ferradás, Enrique; Sánchez Pérez, Juan Francisco; Miñana Aznar, Agustín; Ruiz Gimeno, José; Martínez Alonso, Jesús

    2006-09-21

    A number of models have been proposed to calculate overpressure and impulse from accidental industrial explosions. When the blast is produced by ignition of a vapour cloud, the TNO Multi-Energy model is widely used. From the curves given by this model, data are fitted to obtain equations showing the relationship between overpressure, impulse and distance. These equations, referred herein as characteristic curves, can be fitted by means of power equations, which depend on explosion energy and charge strength. Characteristic curves allow the determination of overpressure and impulse at each distance.

  6. Vacuum sources in obstetrics.

    PubMed

    Wiper, D W; Duchon, M A; Muise, K L

    1996-06-01

    To characterize the performance of vacuum equipment used in operative vaginal deliveries. We measured wall suction in eight Cleveland area labor-and-delivery units. Additionally, we tested samples of hand-operated and electric vacuum pumps. For each apparatus we recorded vacuum in millimeters of mercury using a calibrated, diaphragm-type gauge. We calculated mean maximal vacuum. Work required to produce 500 mm Hg of vacuum was determined for the hand-operated pumps. At increments of vacuum, we compared the vacuum displayed by the gauge head included with the device to our standard. Mean wall suction was 494 mm Hg (range, 248-655). As compared to the Mity-vac, the CMI hand-operated pump needed significantly more work to generate 500 mm Hg of vacuum. Electric pumps produced a reliable and consistent vacuum. Gauges included with the pump had an average error of 4% over 400-600 mm Hg. Wall suction was an unreliable source of vacuum. The two hand-operated pumps tested required significantly different amounts of work to achieve an adequate vacuum. Addition of a fluid trap does not affect the vacuum, and head gauges supplied with vacuum pumps are accurate.

  7. Vacuum system for Advanced Test Accelerator

    SciTech Connect

    Denhoy, B.S.

    1981-09-03

    The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10/sup -6/ torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing.

  8. Overpressure Caused by the Smectite Dehydration Influences on the triggering of fault slip

    NASA Astrophysics Data System (ADS)

    Lin, Wen-Sheng; Liu, Chen-Wuing; Chang, Han-Yuan

    2015-04-01

    Overpressure, which is pore fluid pressure higher than hydrostatic pressure, is observed in numerous mechanical processes along major faults. Many investigations currently show that the pore fluid pressure has been observed to influence the thrust fault strength and slip behavior and updip limit of the seismogenic zone. Clay dehydration is one key control on overpressure generation under undrained condition in thermal pressurization processes. Increasing pressure and temperature with depth depending on the local geological setting and conditions can cause clay dehydration which has been proposed as an explanation for the generation of overpressure. However, study about the effect of excess pore pressure caused by clay dehydration on the triggering of earthquake is seldom addressed in Taiwan. In fault zones like the Chelungpu Fault, clay minerals are abundant in the fault gouge. Therefore, to quantify the effect of overpressure caused by clay dehydration on the triggering of earthquake under undrained condition, we adopt the chemical thermodynamic model and chemical kinetic model to calculate the amount of water expelled from clay dehydration; derive the three-dimensional governing equation of groundwater flow with clay dehydration varied with pressure and temperature; follow the Coulomb-Mohr frictional failure model of earthquake occurrence to evaluate the influence of the pore pressure on the change of effective Coulomb stress. Finally, development of numerical model to simulate the effect of excess pore pressure caused by clay dehydration on the coulomb failure stress coupled thermal-hydraulic-mechanical-chemical has been performed. Moreover, field application with numerical model to quantify analysis of the effect of overpressure caused by clay dehydration on the triggering of earthquake has been progressed. Coulomb stress increases of ≥0.01 MPa have been shown to be associated with seismicity rate increase and in many cases triggering earthquakes. The results

  9. A Wireless Lingual Feedback Device to Reduce Overpressures in Seated Posture: A Feasibility Study

    PubMed Central

    Chenu, Olivier; Vuillerme, Nicolas; Demongeot, Jacques; Payan, Yohan

    2009-01-01

    Background Pressure sores are localized injuries to the skin and underlying tissues and are mainly resulting from overpressure. Paraplegic peoples are particularly subjects to pressure sores because of long-time seated postures and sensory deprivation at the lower limbs. Methodology/Principal Findings Here we report outcomes of a feasibility trial involving a biofeedback system aimed at reducing buttock overpressure whilst an individual is seated. The system consists of (1) pressure sensors, (2) a laptop coupling sensors and actuator (3) a wireless Tongue Display Unit (TDU) consisting of a circuit embedded in a dental retainer with electrodes put in contact with the tongue. The principle consists in (1) detecting overpressures in people who are seated over long periods of time, (2) estimating a postural change that could reduce these overpressures and (3) communicating this change through directional information transmitted by the TDU.Twenty-four healthy subjects voluntarily participated in this study. Twelve healthy subjects initially formed the experimental group (EG) and were seated on a chair with the wireless TDU inside their mouth. They were asked to follow TDU orders that were randomly spread throughout the session. They were evaluated during two experimental sessions during which 20 electro-stimulations were sent. Twelve other subjects, added retrospectively, formed the control group (CG). These subjects participated in one session of the same experiment without any biofeedback.Three dependent variables were computed: (1) the ability of subjects to reach target posture (EG versus CG), (2) high pressure reductions after a biofeedback (EG versus CG) and (3) the level of these reductions relative to their initial values (EG only). Results show (1) that EG reached target postures in 90.2% of the trials, against 5,3% in the CG, (2) a significant reduction in overpressures in the EG compared to the CG and (3), for the EG, that the higher the initial pressures

  10. Miniature self-contained vacuum compatible electronic imaging microscope

    DOEpatents

    Naulleau, Patrick P.; Batson, Phillip J.; Denham, Paul E.; Jones, Michael S.

    2001-01-01

    A vacuum compatible CCD-based microscopic camera with an integrated illuminator. The camera can provide video or still feed from the microscope contained within a vacuum chamber. Activation of an optional integral illuminator can provide light to illuminate the microscope subject. The microscope camera comprises a housing with a objective port, modified objective, beam-splitter, CCD camera, and LED illuminator.

  11. Vacuum-assisted delivery

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on ... the baby through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is ...

  12. 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.

  13. 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.

  14. Identification of low-overpressure interval and its implication to hydrocarbon migration: Case study in the Yanan sag of the Qiongdongnan Basin, South China Sea.

    PubMed

    Xu, Qinghai; Shi, Wanzhong; Xie, Yuhong; Wang, Zhenfeng; Li, Xusheng; Tong, Chuanxin

    2017-01-01

    The Qiongdongnan Basin is a strongly overpressured basin with the maximum pressure coefficient (the ratio of the actual pore pressure versus hydrostatic pressure at the same depth) over 2.27. However, there exists a widespread low-overpressure interval between the strong overpressure intervals in the Yanan Sag of western basin. The mechanisms of the low-overpressure interval are not well understood. Three main approaches, pore pressure test data and well-log analysis, pressure prediction based on the relationship between the deviation of the velocity and the pressure coefficients, and numerical modeling, were employed to illustrate the distribution and evolution of the low-overpressure interval. And we analyzed and explained the phenomenon of the low-overpressure interval that is both underlain and overlain by high overpressure internal. The low-overpressure interval between the strong overpressure intervals can be identified and modelled by drilling data of P-wave sonic and the mud weight, and the numerical modeling using the PetroMod software. Results show that the low-overpressure interval is mainly composed of sandstone sediments. The porosities of sandstone in the low-overpressure interval primarily range from 15%-20%, and the permeabilities range from 10-100 md. Analysis of the geochemical parameters of C1, iC4/nC4, ΔR3, and numerical modeling shows that oil and gas migrated upward into the sandstone in the low-overpressure interval, and then migrated along the sandstone of low-overpressure interval into the Yacheng uplift. The low-overpressure both underlain and overlain by overpressure resulted from the fluids migrating along the sandstones in the low-overpressure interval into the Yacheng uplift since 1.9Ma. The mudstone in the strong overpressure interval is good cap overlain the sandstone of low-overpressure interval, therefore up-dip pinchouts or isolated sandstone in the low-overpressure interval locating the migration path of oil and gas are good

  15. 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.

  16. Characteristic of a triple-cathode vacuum arc plasma source.

    PubMed

    Xiang, W; Li, M; Chen, L

    2012-02-01

    In order to generate a better ion beam, a triple-cathode vacuum arc plasma source has been developed. Three plasma generators in the vacuum arc plasma source are equally located on a circle. Each generator initiated by means of a high-voltage breakdown between the cathode and the anode could be operated separately or simultaneously. The arc plasma expands from the cathode spot region in vacuum. In order to study the behaviors of expanding plasma plume generated in the vacuum arc plasma source, a Langmuir probe array is employed to measure the saturated ion current of the vacuum arc plasma source. The time-dependence profiles of the saturated current density of the triple vacuum arc plasma source operated separately and simultaneously are given. Furthermore, the plasma characteristic of this vacuum arc plasma source is also presented in the paper.

  17. 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…

  18. 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…

  19. Laser-triggered vacuum switch

    DOEpatents

    Brannon, Paul J.; Cowgill, Donald F.

    1990-01-01

    A laser-triggered vacuum switch has a material such as a alkali metal halide on the cathode electrode for thermally activated field emission of electrons and ions upon interaction with a laser beam, the material being in contact with the cathode with a surface facing the discharge gap. The material is preferably a mixture of KCl and Ti powders. The laser may either shine directly on the material, preferably through a hole in the anode, or be directed to the material over a fiber optic cable.

  20. Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

    NASA Astrophysics Data System (ADS)

    Haering, Edward A.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

    2006-05-01

    The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

  1. Flight Demonstration Of Low Overpressure N-Wave Sonic Booms And Evanescent Waves

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Smolka, James W.; Murray, James E.; Plotkin, Kenneth J.

    2005-01-01

    The recent flight demonstration of shaped sonic booms shows the potential for quiet overland supersonic flight, which could revolutionize air transport. To successfully design quiet supersonic aircraft, the upper limit of an acceptable noise level must be determined through quantitative recording and subjective human response measurements. Past efforts have concentrated on the use of sonic boom simulators to assess human response, but simulators often cannot reproduce a realistic sonic boom sound. Until now, molecular relaxation effects on low overpressure rise time had never been compared with flight data. Supersonic flight slower than the cutoff Mach number, which generates evanescent waves, also prevents loud sonic booms from impacting the ground. The loudness of these evanescent waves can be computed, but flight measurement validation is needed. A novel flight demonstration technique that generates low overpressure N-waves using conventional military aircraft is outlined, in addition to initial quantitative flight data. As part of this demonstration, evanescent waves also will be recorded.

  2. Using liquid superheating energy for a quick estimation of overpressure in BLEVEs and similar explosions.

    PubMed

    Casal, Joaquim; Salla, Josep M

    2006-10-11

    A method is proposed for the quick estimation of the peak overpressure caused by a Boiling Liquid Expanding Vapor Explosion (BLEVE) or a similar explosion. The method is based on the use of the "superheating energy" (SE), which is the difference between the specific enthalpy of the liquid at the temperature just before the explosion and the specific enthalpy of the liquid at its saturation temperature, at atmospheric pressure. The analysis performed with a set of reference substances showed that in a BLEVE or in similar explosions, the energy converted into overpressure will range between 3.5 and 14% of SE. The comparison of the values thus obtained with experimental data from the literature shows a fairly good agreement.

  3. Minimization of sonic-boom parameters in real and isothermal atmospheres. [overpressure and acoustic impedance

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1975-01-01

    The procedure for sonic-boom minimization introduced by Seebass and George for an isothermal atmosphere was converted for use in the real atmosphere by means of the appropriate equations for sonic-boom pressure signature advance, ray-tube area, and acoustic impedance. Results of calculations using both atmospheres indicate that except for low Mach numbers or high altitudes, the isothermal atmosphere with a scale height of 7620 m (25 000 ft) gives a reasonable estimate of the values of overpressure, impulse, and characteristic overpressure obtained by using the real atmosphere. The results also show that for aircraft design studies, propagation of a known F-function, or minimization studies at low supersonic Mach numbers, the isothermal approximation is not adequate.

  4. The quantitative assessment of domino effects caused by overpressure. Part I. Probit models.

    PubMed

    Cozzani, Valerio; Salzano, Ernesto

    2004-03-19

    Accidents caused by domino effect are among the more severe that took place in the chemical and process industry. However, a well established and widely accepted methodology for the quantitative assessment of domino accidents contribution to industrial risk is still missing. Hence, available data on damage to process equipment caused by blast waves were revised in the framework of quantitative risk analysis, aiming at the quantitative assessment of domino effects caused by overpressure. Specific probit models were derived for several categories of process equipment and were compared to other literature approaches for the prediction of probability of damage of equipment loaded by overpressure. The results evidence the importance of using equipment-specific models for the probability of damage and equipment-specific damage threshold values, rather than general equipment correlation, which may lead to errors up to 500%.

  5. Intracrystalline nucleation during the post-garnet transformation under large overpressure conditions in deep subducting slabs

    NASA Astrophysics Data System (ADS)

    Nishi, Masayuki; Irifune, Tetsuo; Ohfuji, Hiroaki; Tange, Yoshinori

    2012-12-01

    The mechanism of the post-garnet transformation in natural single-crystalline pyropic garnet has been examined under large overpressure conditions of ˜31-43 GPa using the multianvil apparatus with sintered diamond anvils. Intracrystalline nucleation was found to be dominant above 35-38 GPa, while only grain-boundary nucleation is responsible at lower pressures. In addition, natural pyropic garnet transformed to a single phase of perovskite without decomposing to multiple phases above 38 GPa. Both intracrystalline nucleation and polymorphic growth of the post-garnet transformation under large overpressure conditions would strongly enhance the transformation kinetics. Consequently, the post-garnet transformation may pwroceed rapidly in the subducting slab at depths near ˜950 km, which would cause substantial rheological weakening of the subducting slab. The metastable post-garnet transformation may also cause the seismic discontinuities at a depth of 900-1080 km depth, which is indeed observed beneath some subduction zones.

  6. Neurocognitive and Biomarker Evaluation of Combination mTBI from Blast Overpressure and Traumatic Stress

    DTIC Science & Technology

    2014-11-01

    ABSTRACT Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are major medical issues for the Warfighter. The current project is...designed to evaluate the impact of mild traumatic brain injury (using blast overpressure) and the processes involved in traumatic stress (using a...response system activation. 15. SUBJECT TERMS Traumatic brain injury , post-traumatic stress disorder, blast over pressure 16. SECURITY

  7. Neurocognitive and Biomarker Evaluation of Combination mTBI from Blast Overpressure and Traumatic Stress

    DTIC Science & Technology

    2013-09-01

    traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are major medical issues for the Warfighter. The current project is designed...to evaluate the impact of mild traumatic brain injury (using blast overpressure) and the processes involved in traumatic stress (using a predator...brain injury (mTBI) and post-traumatic stress disorder (PTSD) are medical issues for the war fighter. Sometimes, mTBI and PTSD present a convergence

  8. Method and apparatus for suppressing ignition overpressure in solid rocket propulsion systems

    NASA Technical Reports Server (NTRS)

    Guest, S. H.; Jones, J. H. (Inventor)

    1982-01-01

    The transient overpressure wave produced upon ignition of a solid rocket booster is suppressed by providing within the launch platform, a plurality of pipes and spray heads disposed around the periphery of the exhaust gas plume near its upper end and spraying water into the upper end of the plume during ignition. A large amount of water, preferably equivalent in mass of exhaust products being ejected, is sprayed into the plume in a direction generally perpendicular to plume flow.

  9. Prediction of sonic boom from experimental near-field overpressure data. Volume 1: Method and results

    NASA Technical Reports Server (NTRS)

    Glatt, C. R.; Hague, D. S.; Reiners, S. J.

    1975-01-01

    A computerized procedure for predicting sonic boom from experimental near-field overpressure data has been developed. The procedure extrapolates near-field pressure signatures for a specified flight condition to the ground by the Thomas method. Near-field pressure signatures are interpolated from a data base of experimental pressure signatures. The program is an independently operated ODIN (Optimal Design Integration) program which obtains flight path information from other ODIN programs or from input.

  10. Structural consequences of cohesion in gravitational instabilities triggered by fluid overpressure: Analytical derivation and experimental testing

    NASA Astrophysics Data System (ADS)

    Mourgues, R.; Costa, A. C. G.; Marques, F. O.; Lacoste, A.; Hildenbrand, A.

    2016-06-01

    The critical taper theory of Coulomb wedges has been classically applied to compressive regimes (accretionary prisms/fold-and-thrust belts), and more recently to gravitational instabilities. Following the initial hypothesis of the theory, we provide an alternative expression of the exact solution for a non-cohesive wedge by considering the balance of forces applied to the external surfaces. Then, we use this approach to derive a solution for the case of cohesive wedges. We show that cohesion has conspicuous structural effects, including a minimum length required for sliding and the formation of listric faults. The stabilizing effect of cohesion is accentuated in the foremost thin domain of the wedge, defining a required Minimum Failure Length (MFL), and producing sliding of a rigid mass above the detachment. This MFL decreases with less cohesion, a smaller coefficient of internal friction, larger fluid overpressure ratio, and steeper upper and basal surfaces for the wedge. Listricity of the normal faults depends on the fluid overpressure magnitude within the wedge. For moderate fluid overpressure, normal faults are curved close to the surface, and become straight at depth. In contrast, where fluid overpressure exceeds a critical value corresponding to the fluid pressure required to destabilize the surface of a noncohesive wedge, the state of stress changes and rotates at depth. The faults are straight close to the surface and listric at depth, becoming parallel to the upper surface if the wedge is thick enough. We tested some of these structural effects of a cohesive wedge on gravitational instabilities using analogue models where cohesive material was subjected to pore-fluid pressure. The shape of the faults obtained in the models is consistent with the predictions of the theory.

  11. Role of fluid overpressures in crustal strength and the form of the brittle-ductile transition

    NASA Astrophysics Data System (ADS)

    Suppe, J.

    2014-12-01

    The classic crustal strength-depth model of Brace and Kolhstedt (1980) (see figure) based on experimental rock mechanics depends in the brittle regime on the critical assumption of linearly increasing hydrostatic pore-fluid pressures. This leads to a predicted linearly increasing brittle strength that is well established based on deep borehole stress measurements in crystalline crust. In contrast, fluid overpressures are widely documented in orogenic belts based on borehole data, seismic velocity analysis and analysis of veins, in some cases showing complex fault-valve pressure fluctuations between lithostatic and hydrostatic. Typical observed overpressure-depth relationships predict a brittle crustal strength that is approximately constant with depth in contrast with the classic model. This constant-strength behavior below the fluid-retention depth (ZFRD in figure) has been confirmed using deep borehole stress and fluid-pressure measurements (Suppe, 2014). Recent ductile-plastic modeling of disequilibrium compaction suggests that pressure solution promotes further increases in overpressure and weakening, promoting a very prolonged low-strength brittle-ductile transition. Overpressured conditions can be inferred to exist over a substantial fraction of crustal thickness, spanning the brittle-ductile transition, in several tectonic environments, most straightforwardly in shale-rich clastic sedimentary basins built to sea level on oceanic or highly thinned continental crust such as the US Gulf Coast and Niger Delta. These thick accumulations commonly deform into shale-rich plate boundary mountain belts (e.g. Bangladesh/Miyanmar, Makran, Trinidad/Barbados, Gulf of Alaska, southern Taiwan and New Zealand). There is deep geophysical evidence for near lithostatic pore-fluid pressures existing to depths of 20-30km based on Vp, Vs, Vp/Vs and Q observations. We present active examples from Taiwan and New Zealand, combining borehole data and seismic tomography.

  12. Rovibrationally selected ion-molecule collision study using the molecular beam vacuum ultraviolet laser pulsed field ionization-photoion method: charge transfer reaction of N2(+)(X 2Σg+; v+ = 0-2; N+ = 0-9) + Ar.

    PubMed

    Chang, Yih Chung; Xu, Yuntao; Lu, Zhou; Xu, Hong; Ng, C Y

    2012-09-14

    We have developed an ion-molecule reaction apparatus for state-selected absolute total cross section measurements by implementing a high-resolution molecular beam vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) ion source to a double-quadrupole double-octopole ion-guide mass spectrometer. Using the total cross section measurement of the state-selected N(2)(+)(v(+), N(+)) + Ar charge transfer (CT) reaction as an example, we describe in detail the design of the VUV laser PFI-PI ion source used, which has made possible the preparation of reactant N(2)(+)(X (2)Σ(g)(+), v(+) = 0-2, N(+) = 0-9) PFI-PIs with high quantum state purity, high intensity, and high kinetic energy resolution. The PFI-PIs and prompt ions produced in the ion source are shown to have different kinetic energies, allowing the clean rejection of prompt ions from the PFI-PI beam by applying a retarding potential barrier upstream of the PFI-PI source. By optimizing the width and amplitude of the pulsed electric fields employed to the VUV-PFI-PI source, we show that the reactant N(2)(+) PFI-PI beam can be formed with a laboratory kinetic energy resolution of ΔE(lab) = ± 50 meV. As a result, the total cross section measurement can be conducted at center-of-mass kinetic energies (E(cm)'s) down to thermal energies. Absolute total rovibrationally selected cross sections σ(v(+) = 0-2, N(+) = 0-9) for the N(2)(+)(X (2)Σ(g)(+); v(+) = 0-2, N(+) = 0-9) + Ar CT reaction have been measured in the E(cm) range of 0.04-10.0 eV, revealing strong vibrational enhancements and E(cm)-dependencies of σ(v(+) = 0-2, N(+) = 0-9). The thermochemical threshold at E(cm) = 0.179 eV for the formation of Ar(+) from N(2)(+)(X; v(+) = 0, N(+)) + Ar was observed by the measured σ(v(+) = 0), confirming the narrow ΔE(cm) spread achieved in the present study. The σ(v(+) = 0-2; N(+)) values obtained here are compared with previous experimental and theoretical results. The theoretical predictions

  13. Distribution and generation of the overpressure system, Eastern Delaware Basin, Western Texas and Southern New Mexico: Discussion

    SciTech Connect

    Swarbrick, R.E.

    1995-12-01

    Luo et al. (1994) discussed the distribution and possible origin of a three-fold pressure system in the eastern Delaware basin. The pressure data presented in their pressure vs. depth plots were exclusively derived from drill-stem tests (DSTs), although they contend that the overpressure is also confirmed from well log responses. The paper is weakened by incorrect sourece of pressure data from DSTs, and also by poor understanding and inadequate review of the basis for overpressure generation in sedimentary basins.

  14. An Evaluation of the Compressive Properties of Helmet Pads Pre- and Post-Shock Wave Overpressure Exposure

    DTIC Science & Technology

    2015-08-14

    COMPRESSIVE PROPERTIES OF HELMET PADS PRE - AND POST- SHOCK WAVE OVERPRESSURE EXPOSURE by Marina Carboni Xiaolin Zhen Barry DeCristofano and... PRE - AND POST-SHOCK WAVE OVERPRESSURE EXPOSURE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Marina Carboni...release; distribution is unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT This report documents a study of the compressive properties between pre - and

  15. Analysis of over-pressure mechanisms in the Uinta Basin, Utah

    SciTech Connect

    McPherson, B.; Bredehoeft, J.

    1995-03-01

    Extremely high pore fluid pressures exist in the area of the Altamount/Bluebell oil field in the Uinta basin, Utah. We discuss two possible mechanisms for the cause of these over-pressures in this paper: (1) compaction disequilibrium, and (2) conversion of kerogen to liquid hydrocarbon (oil). Compaction disequilibrium occurs during periods of rapid sedimentation. If the permeability of deeply buried strata is low, then connate water within the rock matrix does not escape rapidly enough as compaction occurs; as sedimentary deposition continues, high pore fluid pressures develop. Conversion of solid kerogen to a liquid generates both a liquid and additional pore space for the liquid to occupy. If the volume of the liquid generated is just sufficient to fill the pore space generated, then there will be no accompanying effect on the pore pressure. If the liquid is less dense than the solid it replaces, then there is more liquid than pore space created; pore pressure will increase, causing flow away from the area of the reaction. Pore pressure is a sensitive measure of the balance between hydrocarbon generation and expulsion from the source into adjacent strata. If high pore pressures exist only where source rocks are thought to be generating oil, then kerogen conversion is a likely over-pressure mechanism. However, if over-pressures are found in low-permeability strata regardless of source rock proximity, then sedimentary compaction is probably a more dominant mechanism.

  16. Development of a multimodal blast sensor for measurement of head impact and over-pressurization exposure.

    PubMed

    Chu, Jeffrey J; Beckwith, Jonathan G; Leonard, Daniel S; Paye, Corey M; Greenwald, Richard M

    2012-01-01

    It is estimated that 10-20% of United States soldiers returning from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) have suffered at least one instance of blast-induced traumatic brain injury (bTBI) with many reporting persistent symptomology and long-term effects. This variation in blast response may be related to the complexity of blast waves and the many mechanisms of injury, including over-pressurization due to the shock wave and potential for blunt impacts to the head from shrapnel or from other indirect impacts (e.g., building, ground, and vehicle). To help differentiate the effects of primary, secondary, and tertiary effects of blast, a custom sensor was developed to simultaneously measure over-pressurization and blunt impact. Moreover, a custom, complementary filter was designed to differentiate the measurements of blunt (low-frequency bandwidth) from over-pressurization (high-frequency bandwidth). The custom sensor was evaluated in the laboratory using a shock tube to simulate shock waves and a drop fixture to simulate head impacts. Both bare sensors and sensor embedded within an ACH helmet coupon were compared to laboratory reference transducers under multiple loading conditions (n = 5) and trials at each condition (n = 3). For all comparative measures, peak magnitude, peak impulse, and cross-correlation measures, R (2) values, were greater than 0.900 indicating excellent agreement of peak measurements and time-series comparisons with laboratory measures.

  17. Rupture threshold characterization of polymer-shelled ultrasound contrast agents subjected to static overpressure

    PubMed Central

    Chitnis, Parag V.; Lee, Paul; Mamou, Jonathan; Allen, John S.; Böhmer, Marcel; Ketterling, Jeffrey A.

    2011-01-01

    Polymer-shelled micro-bubbles are employed as ultrasound contrast agents (UCAs) and vesicles for targeted drug delivery. UCA-based delivery of the therapeutic payload relies on ultrasound-induced shell rupture. The fragility of two polymer-shelled UCAs manufactured by Point Biomedical or Philips Research was investigated by characterizing their response to static overpressure. The nominal diameters of Point and Philips UCAs were 3 μm and 2 μm, respectively. The UCAs were subjected to static overpressure in a glycerol-filled test chamber with a microscope-reticule lid. UCAs were reconstituted in 0.1 mL of water and added over the glycerol surface in contact with the reticule. A video-microscope imaged UCAs as glycerol was injected (5 mL∕h) to vary the pressure from 2 to 180 kPa over 1 h. Neither UCA population responded to overpressure until the rupture threshold was exceeded, which resulted in abrupt destruction. The rupture data for both UCAs indicated three subclasses that exhibited different rupture behavior, although their mean diameters were not statistically different. The rupture pressures provided a measure of UCA fragility; the Philips UCAs were more resilient than Point UCAs. Results were compared to theoretical models of spherical shells under compression. Observed variations in rupture pressures are attributed to shell imperfections. These results may provide means to optimize polymeric UCAs for drug delivery and elucidate associated mechanisms. PMID:21580800

  18. Rupture threshold characterization of polymer-shelled ultrasound contrast agents subjected to static overpressure.

    PubMed

    Chitnis, Parag V; Lee, Paul; Mamou, Jonathan; Allen, John S; Böhmer, Marcel; Ketterling, Jeffrey A

    2011-04-15

    Polymer-shelled micro-bubbles are employed as ultrasound contrast agents (UCAs) and vesicles for targeted drug delivery. UCA-based delivery of the therapeutic payload relies on ultrasound-induced shell rupture. The fragility of two polymer-shelled UCAs manufactured by Point Biomedical or Philips Research was investigated by characterizing their response to static overpressure. The nominal diameters of Point and Philips UCAs were 3 μm and 2 μm, respectively. The UCAs were subjected to static overpressure in a glycerol-filled test chamber with a microscope-reticule lid. UCAs were reconstituted in 0.1 mL of water and added over the glycerol surface in contact with the reticule. A video-microscope imaged UCAs as glycerol was injected (5 mL∕h) to vary the pressure from 2 to 180 kPa over 1 h. Neither UCA population responded to overpressure until the rupture threshold was exceeded, which resulted in abrupt destruction. The rupture data for both UCAs indicated three subclasses that exhibited different rupture behavior, although their mean diameters were not statistically different. The rupture pressures provided a measure of UCA fragility; the Philips UCAs were more resilient than Point UCAs. Results were compared to theoretical models of spherical shells under compression. Observed variations in rupture pressures are attributed to shell imperfections. These results may provide means to optimize polymeric UCAs for drug delivery and elucidate associated mechanisms.

  19. Lateral variations of subsalt overpressure buildup in the Gulf of Mexico

    SciTech Connect

    Malloy, S.; Petersen, K.; Lerche, I.; Lowrie, A.

    1996-09-01

    The confining pressure exerted by the prograding Tertiary clastic wedge has caused extensive salt deformation in the Gulf of Mexico. The high rates of lateral salt motion from the Louisiana shelf break to the Sigsbee Escarpment are expected to have significant impact on the dynamic evolution of the surrounding sedimentary formations. The evolution of fluid pressure in supra and subsalt sediments has been modeled in a series of pseudo-wells along a profile intersecting numerous salt sheets and structures offshore Louisiana. Based upon the estimated rates of salt movement, the timing can be determined for insertion/depletion of salt in the sediments as the salt has moved through, and by, sediments on its way basinward. An execution of a series of I-D fluid/flow compaction models has enabled estimation of the spatial variation in overpressure build-up with time. The quantitative behaviors suggest that the speed of lateral salt insertion and the thickness of the salt are the main factors, causing anomalous overpressure build-up. A quantification of the dynamic behaviors is significant when modeling the timing of potential trapping of hydrocarbons beneath salt sheets and of the sub-salt overpressure to be expected in sub-salt drilling.

  20. Overpressure protection of multiphase oil and gas production flowlines in flat or hilly terrain

    SciTech Connect

    Greaney, P.K.

    1997-05-01

    Long flowlines networking multiple wells to a central facility require overpressure protection if they are incapable of withstanding the maximum shut-in wellhead pressure and if a flowline valve at the central facility can be closed. A main component of this overpressure protection system is a relief valve or set of relief valves on the flowline at the central facility. The relief valves should have set pressures and large enough orifice areas so that no section of the flowline network becomes overpressured, especially the section most remote from the central facility. At the remote section, the pressure is significantly higher than the pressure at the relief valves at the central production facility. Proper application of multiphase hydraulic calculations is critical in determining the relationship between the central facility pressure (relief valve pressure) and the pressure at the remote well during a relief situation. Horizontal flowlines are relatively easy to analyze, but long flowlines in hilly terrain with significant upflow and downflow sections complicate the hydraulic analysis. This paper presents a methodology for determining the relief valve set pressure and orifice area for both flat horizontal flowlines and flowlines in hilly terrain. The methodology consists of simplifying the analysis by substituting worst case steady-state solutions for full transient solutions and by demonstrating that the steady-state solutions are more conservative than the transient ones.

  1. Rupture threshold characterization of polymer-shelled ultrasound contrast agents subjected to static overpressure

    NASA Astrophysics Data System (ADS)

    Chitnis, Parag V.; Lee, Paul; Mamou, Jonathan; Allen, John S.; Böhmer, Marcel; Ketterling, Jeffrey A.

    2011-04-01

    Polymer-shelled micro-bubbles are employed as ultrasound contrast agents (UCAs) and vesicles for targeted drug delivery. UCA-based delivery of the therapeutic payload relies on ultrasound-induced shell rupture. The fragility of two polymer-shelled UCAs manufactured by Point Biomedical or Philips Research was investigated by characterizing their response to static overpressure. The nominal diameters of Point and Philips UCAs were 3 μm and 2 μm, respectively. The UCAs were subjected to static overpressure in a glycerol-filled test chamber with a microscope-reticule lid. UCAs were reconstituted in 0.1 mL of water and added over the glycerol surface in contact with the reticule. A video-microscope imaged UCAs as glycerol was injected (5 mL/h) to vary the pressure from 2 to 180 kPa over 1 h. Neither UCA population responded to overpressure until the rupture threshold was exceeded, which resulted in abrupt destruction. The rupture data for both UCAs indicated three subclasses that exhibited different rupture behavior, although their mean diameters were not statistically different. The rupture pressures provided a measure of UCA fragility; the Philips UCAs were more resilient than Point UCAs. Results were compared to theoretical models of spherical shells under compression. Observed variations in rupture pressures are attributed to shell imperfections. These results may provide means to optimize polymeric UCAs for drug delivery and elucidate associated mechanisms.

  2. Overpressurized fluids drive microseismic swarm activity around Mt. Ontake volcano, Japan

    NASA Astrophysics Data System (ADS)

    Terakawa, Toshiko

    2017-06-01

    Microseismic swarm activity has taken place since 1976 around Mt. Ontake, the second highest stratovolcano in Japan. This activity is thought to be linked to high pore-fluid pressure in the vicinity of the volcano. We analyzed well-constrained focal mechanism solutions of microseismicity to re-estimate the 3-D pore-fluid pressure field driving vigorous swarm activity around Mt. Ontake. Pore-fluid pressures were measured by mapping earthquake focal mechanisms on the 3-D Mohr diagram for the regional stress field with high resolutions of 2-5 km. The assumption of the reference stress pattern can cause modeling errors in measurements of pore-fluid pressure. To remove the effect, we statistically evaluated the estimation errors of the regional stress field and included these errors in the analysis. We detected an overpressurized fluid reservoir with a peak of about 10-30 MPa in the east flank of Mt. Ontake, where microseismic swarm activity has been vigorous for the last two decades. The level of pore-fluid pressure was maintained for at least 5 years after 2009. This finding indicates that there are some interactions between the intensive swarm activity and overpressurized fluids: the swarm activity has been driven by overpressurized fluids, whereas pore-fluid pressures have been suppressed by the swarm activity.[Figure not available: see fulltext.

  3. Nanoscale Vacuum Channel Transistor.

    PubMed

    Han, Jin-Woo; Moon, Dong-Il; Meyyappan, M

    2017-04-12

    Vacuum tubes that sparked the electronics era had given way to semiconductor transistors. Despite their faster operation and better immunity to noise and radiation compared to the transistors, the vacuum device technology became extinct due to the high power consumption, integration difficulties, and short lifetime of the vacuum tubes. We combine the best of vacuum tubes and modern silicon nanofabrication technology here. The surround gate nanoscale vacuum channel transistor consists of sharp source and drain electrodes separated by sub-50 nm vacuum channel with a source to gate distance of 10 nm. This transistor performs at a low voltage (<5 V) and provides a high drive current (>3 microamperes). The nanoscale vacuum channel transistor can be a possible alternative to semiconductor transistors beyond Moore's law.

  4. Effect of host-rock rheology on dyke shape, thickness and magma overpressure

    NASA Astrophysics Data System (ADS)

    Vachon, Rémi; Hieronymus, Christoph F.

    2017-03-01

    The size and thickness of dykes is of fundamental importance for volcano dynamics because dykes are the primary path for magma transport, and because large numbers of dykes often comprise a major proportion of the volcanic edifice and of the underlying crust. Standard elastic models predict dyke geometry to be elliptic in cross-section for constant overpressure and uniform host-rock properties, whereas observations show that dyke thickness is typically more nearly constant with a sharp taper at the ends. Moreover, the predicted overpressures required to inflate dykes in a purely elastic medium are often significantly higher (>150 MPa and up to 2 GPa) than those estimated by other means (about 1-50 MPa). In this study, we use 2-D finite element models to test whether other host-rock rheologies lead to more realistic dyke shapes and overpressures. We examine three different rheologies, each of which is affected by the presence of the dyke itself: (1) elasticity with reduced moduli in regions of low pressure or tension; (2) elastoplasticity with plastic failure in the high-stress regions surrounding the dyke tips; (3) viscoelasticity with a viscosity decrease due to heating by the dyke. We use rheological parameters obtained from laboratory experiments whenever possible, and assume static conditions for the final dyke shape. We find that all three rheologies tend to make the dyke more rectangular relative to the elliptical dykes of the linearly elastic models. The change in shape is due to enhanced deformation in the high-stress zone surrounding the dyke tip. We also find that the overpressure required to inflate an initially thin dyke to a given thickness is reduced for all three rheologies. The greatest decrease in overpressure by a factor of about 0.1 is observed for the elastoplastic model, and for the viscoelastic model if the dyke intrudes into moderately pre-heated host-rock. We discuss our results with respect to dyke observations from Rum Island (Scotland

  5. Exposure to sublethal blast overpressure reduces the food intake and exercise performance of rats.

    PubMed

    Bauman, R A; Elsayed, N; Petras, J M; Widholm, J

    1997-07-25

    Exposure to blast overpressure can typically inflict generalized damage on major organ systems, especially gas-containing organs such as the lungs and the gastrointestinal tract. The purpose of the present study was to use rat's food intake and exercise wheel running as behavioral correlates of the perhaps more subtle damage to these organ systems induced by sublethal blast overpressure. Toward this end, all rats were exposed to a 12-h light/dark cycle and food was available only in the dark period. Prior to exposure, rats in the (E)xercise group were required to execute five rotations of an activity wheel for a food pellet; wheel turns that occurred at times other than when a rat was feeding were recorded separately and labeled exercise running. In the (S)edentary and (A)nesthesia groups, wheel running was not possible and rats were required to execute five leverpresses for a single pellet. A compressed air-driven shock tube was used to expose rats to a supra-atmospheric wave of air pressure. The tube was separated into two sections by a polyester membrane, the thickness of which determined peak and duration of overpressure. All rats were anesthetized with 50 mg/kg of phenobarbital. After reaching a deep plane of anesthesia, they were individually tied in a stockinet across one end of the shock tube. In preliminary tests, the membrane thickness was 1000 (A)ngstroms and rats in Group L(ethality) were exposed to a 129 kPa (peak amplitude) wave of overpressure. Three of six rats survived exposure to this peak pressure; pathology was evident in the lungs and gastrointestinal tract of all non-survivors. Rats in Groups E and S were tested with a 500 A membrane, which resulted in an 83 kPa peak amplitude. All rats survived exposure to this lower peak pressure. On the day of exposure to blast, the relative reduction of intake during the first 3 h of the dark period was significantly greater for Group E than for Groups S and A; the intake of Groups E and S remained reduced

  6. Effect of host-rock rheology on dyke shape, thickness, and magma overpressure.

    NASA Astrophysics Data System (ADS)

    Vachon, Rémi; Hieronymus, Christoph F.

    2016-12-01

    The size and thickness of dykes is of fundamental importance for volcano dynamics because dykes are the primary path for magma transport, and because large numbers of dykes often comprise a major proportion of the volcanic edifice and of the underlying crust. Standard elastic models predict dyke geometry to be elliptic in cross-section for constant overpressure and uniform host-rock properties, whereas observations show that dyke thickness is typically more nearly constant with a sharp taper at the ends. Moreover, the predicted overpressures required to inflate dykes in a purely elastic medium are often significantly higher (>150 MPa and up to 2 GPa) than those estimated by other means (about 1-50 MPa). In this study, we use two-dimensional finite element models to test whether other host-rock rheologies lead to more realistic dyke shapes and overpressures. We examine 3 different rheologies, each of which is affected by the presence of the dyke itself: (1) elasticity with reduced moduli in regions of low pressure or tension; (2) elasto-plasticity with plastic failure in the high-stress regions surrounding the dyke tips; (3) visco-elasticity with a viscosity decrease due to heating by the dyke. We use rheological parameters obtained from laboratory experiments whenever possible, and assume static conditions for the final dyke shape. We find that all 3 rheologies tend to make the dyke more rectangular relative to the elliptical dykes of the linearly elastic models. The change in shape is due to enhanced deformation in the high-stress zone surrounding the dyke tip. We also find that the overpressure required to inflate an initially thin dyke to a given thickness is reduced for all 3 rheologies. The greatest decrease in overpressure by a factor of about 0.1 is observed for the elasto-plastic model, and for the visco-elastic model if the dyke intrudes into moderately pre-heated host-rock. We discuss our results with respect to dyke observations from Rum Island (Scotland

  7. 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

  8. Resonant Circuits and Introduction to Vacuum Tubes, Industrial Electronics 2: 9325.03. Course Outline.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    The 135 clock-hour course for the 11th year consists of outlines for blocks of instruction on series resonant circuits, parallel resonant circuits, transformer theory and application, vacuum tube fundamentals, diode vacuum tubes, triode tube construction and parameters, vacuum tube tetrodes and pentodes, beam-power and multisection tubes, and…

  9. Design of the Vacuum Feedthrough for the EAST ICRF Antenna

    NASA Astrophysics Data System (ADS)

    Yang, Qingxi; Song, Yuntao; Wu, Songtao; Zhao, Yanping

    2011-04-01

    Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency (ICRF) antenna in EAST, along with an electro-analysis and thermal structural analysis, is presented. The electric field, the voltage standing wave ratio (VSWR) and the stresses in the vacuum feedthrough are studied. A method using the rings of oxygen-free copper as the cushion and macro-beam plasma arc welding is applied in the assembly to protect the ceramic from being damaged during welding. The vacuum leak test on the prototype of vacuum feedthrough is introduced.

  10. Advanced photon source experience with vacuum chambers for insertion devices

    SciTech Connect

    Hartog, P.D.; Grimmer, J.; Xu, S.; Trakhtenberg, E.; Wiemerslage, G.

    1997-08-01

    During the last five years, a new approach to the design and fabrication of extruded aluminum vacuum chambers for insertion devices was developed at the Advanced Photon Source (APS). With this approach, three different versions of the vacuum chamber, with vertical apertures of 12 mm, 8 mm, and 5 mm, were manufactured and tested. Twenty chambers were installed into the APS vacuum system. All have operated with beam, and 16 have been coupled with insertion devices. Two different vacuum chambers with vertical apertures of 16 mm and 11 mm were developed for the BESSY-II storage ring and 3 of 16 mm chambers were manufactured.

  11. High throughput vacuum chemical epitaxy

    NASA Astrophysics Data System (ADS)

    Fraas, L. M.; Malocsay, E.; Sundaram, V.; Baird, R. W.; Mao, B. Y.; Lee, G. Y.

    1990-10-01

    We have developed a vacuum chemical epitaxy (VCE) reactor which avoids the use of arsine and allows multiple wafers to be coated at one time. Our vacuum chemical epitaxy reactor closely resembles a molecular beam epitaxy system in that wafers are loaded into a stainless steel vacuum chamber through a load chamber. Also as in MBE, arsenic vapors are supplied as reactant by heating solid arsenic sources thereby avoiding the use of arsine. However, in our VCE reactor, a large number of wafers are coated at one time in a vacuum system by the substitution of Group III alkyl sources for the elemental metal sources traditionally used in MBE. Higher wafer throughput results because in VCE, the metal-alkyl sources for Ga, Al, and dopants can be mixed at room temperature and distributed uniformly though a large area injector to multiple substrates as a homogeneous array of mixed element molecular beams. The VCE reactor that we have built and that we shall describe here uniformly deposits films on 7 inch diameter substrate platters. Each platter contains seven two inch or three 3 inch diameter wafers. The load chamber contains up to nine platters. The vacuum chamber is equipped with two VCE growth zones and two arsenic ovens, one per growth zone. Finally, each oven has a 1 kg arsenic capacity. As of this writing, mirror smooth GaAs films have been grown at up to 4 μm/h growth rate on multiple wafers with good thickness uniformity. The background doping is p-type with a typical hole concentration and mobility of 1 × 10 16/cm 3 and 350 cm 2/V·s. This background doping level is low enough for the fabrication of MESFETs, solar cells, and photocathodes as well as other types of devices. We have fabricated MESFET devices using VCE-grown epi wafers with peak extrinsic transconductance as high as 210 mS/mm for a threshold voltage of - 3 V and a 0.6 μm gate length. We have also recently grown AlGaAs epi layers with up to 80% aluminum using TEAl as the aluminum alkyl source. The Al

  12. How can fluid overpressures be developed and maintained in crustal fault zones ?

    NASA Astrophysics Data System (ADS)

    LECLÈRE, H.; Cappa, F.; Faulkner, D. R.; Armitage, P. J.; Blake, O. O.; Fabbri, O.

    2013-12-01

    The presence of fluid overpressure in crustal fault zones is known to play a key role on the stability of faults and it has often been invoked to explain the triggering of earthquakes and the apparent weakness of misoriented faults. However, the mechanisms allowing the development and maintenance of fluid overpressures in fault remain unresolved. We investigate how fluid overpressures can be developed and maintained in complex fault zones with hydraulic and elastic heterogeneities. Here we address this question combining geological observations, laboratory experiments and hydromechanical models of an active crustal fault zone in the Ubaye-Argentera area (southeastern France). The fault zone studied is located in the Argentera external crystalline massif and is connected to regional NW-SE steeply-dipping dextral strike-slip faults with an offset of several kilometers. The fault zone cuts through migmatitic gneisses composed of quartz, K-feldspar, plagioclase, biotite and muscovite. It exposes several anastomosing core zones surrounded by damage zones with a pluri-decametric total width. The core zones are made up of centimetric to pluridecimetric phyllosilicate-rich gouge layers while the damage zones are composed of pluri-metric phyllonitic rock derived from mylonite. The determination of fault structure in the field and its hydraulic and mechanical properties in the lab are key aspects to improve our understanding of the role of fluids in fault mechanics and earthquake triggering. Here, the permeability and elastic moduli of the host rock, damage zone and fault core were measured from natural plugs with a diameter of 20 mm and lengths between 26 to 51 mm, using a high-pressure hydrostatic fluid-flow apparatus. Measurements were made with confining pressures ranging from 30 to 210 MPa and using argon pore fluid pressure of 20 MPa. Data show a reduction of the permeability values of one order of magnitude between host rock and fault damage zone and a decrease of 50

  13. 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.

  14. Thermodynamic modelling of phase equilibrium in system Ti-B-Si-C, synthesis and phases composition of borides and carbides layers on titanic alloyVT-1 at electron beam treatment in vacuum

    NASA Astrophysics Data System (ADS)

    Smirnyagina, N. N.; Khaltanova, V. M.; Lapina, A. E.; Dasheev, D. E.

    2017-01-01

    Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VT-1 are generated at diffused saturation in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

  15. Coherent instabilities of a relativistic bunched beam

    SciTech Connect

    Chao, A.W.

    1982-06-01

    A charge-particle beam contained in an accelerator vacuum chamber interacts electromagnetically with its environment to create a wake field. This field than acts back on the beam, perturbing the particle motion. If the beam intensity is high enough, this beam-environment interaction may lead to an instability and to subsequent beam loss. The beam and its environment form a dynamical system, and it is this system that will be studied. 84 references.

  16. Vacuum pump aids ejectors

    SciTech Connect

    Nelson, R.E.

    1982-12-01

    The steam ejector/vacuum pump hybrid system has been operating satisfactorily since the summer of 1981. This system has essentially been as troublefree as the all-ejector system and, of course, has provided a substantial cost savings. Construction is currently under way to convert the vacuum system of another crude still which is equipped with steam ejectors and barometric condensers to the hybrid system of steam ejectors, surface condensers, and vacuum pumps. This current project is even more financially attractive because it allows a dirty water cooling tower which serves the barometric condensers to be shut down. Providing a vacuum for crude distillation vacuum towers with this hybrid system is by no means the only application of this technique. Any vacuum system consisting of all steam ejectors would be a candidate for this hybrid system and the resulting savings in energy.

  17. Alignment Fixtures For Vacuum-Plasma-Spray Gun

    NASA Technical Reports Server (NTRS)

    Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

    1993-01-01

    Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.

  18. Alignment Fixtures For Vacuum-Plasma-Spray Gun

    NASA Technical Reports Server (NTRS)

    Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

    1993-01-01

    Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.

  19. Maintaining vacuum furnaces

    SciTech Connect

    Kowalewski, J.

    2000-04-01

    A preventive maintenance program is essential for safe and consistent vacuum furnace operation. The program should be developed in cooperation with safety, maintenance, and furnace operators, implemented as soon as the furnace is commissioned, and adhered to throughout the life of the furnace. This article serves as an introduction to the topic of vacuum furnace preventive maintenance. Basic information about installing a new vacuum furnace also is provided.

  20. 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.

  1. Gravitation and vacuum field

    SciTech Connect

    Tevikyan, R.V.

    1986-03-01

    This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E ..-->.. infinity. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory.

  2. Vacuum chamber thermal protection for the APS (Advanced Photon Source)

    SciTech Connect

    Kramer, S.L.; Crosbie, E.A.; Kim, S.; Wehrle, R.; Yoon, M.

    1989-01-01

    The addition of undulators and wigglers into synchrotron storage rings created new problems in terms of protecting the integrity of the ring vacuum chamber. If the photon beam from these devices were missteered into striking an inadequately cooled section of the storage ring vacuum chamber, the structural strength might be reduced sufficiently that the vacuum envelope could be penetrated, resulting in long downtime of the storage ring. The new generation of high-energy synchrotron light sources will produce photon beams of such high power density that cooling of the vacuum chamber will not prevent a potential penetration of the vacuum envelope, and other methods of preventing this occurrence will be required. Since active methods will be used to ensure that the beams are delivered to beam lines for users during normal operation, there is a need for passive protection methods during non-routine operation, such as turning on new beam lines, injection, etc., when the active systems may be disabled. In addition, the passive methods could prevent the problem from arising and provide the rapid time response necessary for the highest power beams, a property that might not be easily and reliably provided by active methods during the early operation of these machines. This paper summarizes the results of a task group that studied the problem and outlines passive methods of protection for the Advanced Photon Source (APS). 2 refs., 3 figs., 1 tab.

  3. XVIIth international symposium on discharges and electrical insulation in vacuum. Volume 1 and 2

    SciTech Connect

    1996-12-31

    This is the proceedings of the XVIIth International Symposium on Discharges and Electrical Insulation in Vacuum, held in Berkeley, CA, July 21-26, 1996. Papers were presented in the following areas: vacuum breakdown and prebreakdown phenomena; vacuum arcs; switching in vacuum; surface flashover; vacuum insulation including magnetic insulation, accelerators, and others; high current diodes, intense particle beams, and vacuum arc ion sources; discharges in the space environment; arcing in controlled fusion devices; emission processes and electrode phenomena; cathodic arc deposition; pseudospark discharges; industrial applications. Separate abstracts have been indexed into the database for some articles from this proceedings.

  4. Internal triggering of volcanic eruptions: tracking overpressure regimes for giant magma bodies

    NASA Astrophysics Data System (ADS)

    Tramontano, Samantha; Gualda, Guilherme A. R.; Ghiorso, Mark S.

    2017-08-01

    Understanding silicic eruption triggers is paramount for deciphering explosive volcanism and its potential societal hazards. Here, we use phase equilibria modeling to determine the potential role of internal triggering - wherein magmas naturally evolve to a state in which eruption is inevitable - in rhyolitic magma bodies. Whole-rock compositions from five large to super-sized rhyolitic deposits are modeled using rhyolite-MELTS. By running simulations with varying water contents, we can track crystallization and bubble exsolution during magma solidification. We use simulations with variable enthalpy and fixed pressure for the five compositions. The interplay between bubble exsolution and crystallization can lead to an increase in the system volume, which can lead to magma overpressurization. We find that internal triggering is possible for high-silica rhyolite magmas crystallizing at pressures below 300 MPa (<11 km depth in the crust), revealing a window of eruptibility within the upper crust from which high-silica eruptions emanate. At higher pressures, the critical overpressure threshold for eruption is only reached once crystallinities are high, >50 wt.%, which makes magma immobile - high-silica rhyolite eruptions from such depths would require external triggering, but examples are scarce or entirely absent. Calculated crystallinities at which the critical overpressure threshold is reached compare favorably with observed crystal contents in natural samples for many systems, suggesting that internal evolution plays a critical role in triggering eruptions. Systems in which fluid saturation happens late relative to crystallization or in which degassing is effective can delay or avoid internal triggering. We argue that priming by crystallization and bubble exsolution is critical for magma eruption, and external triggering serves simply as the final blow - rather than being the driving force - of explosive rhyolitic eruptions.

  5. Characterization of the Scale Model Acoustic Test Overpressure Environment using Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Nielsen, Tanner; West, Jeff

    2015-01-01

    The Scale Model Acoustic Test (SMAT) is a 5% scale test of the Space Launch System (SLS), which is currently being designed at Marshall Space Flight Center (MSFC). The purpose of this test is to characterize and understand a variety of acoustic phenomena that occur during the early portions of lift off, one being the overpressure environment that develops shortly after booster ignition. The pressure waves that propagate from the mobile launcher (ML) exhaust hole are defined as the ignition overpressure (IOP), while the portion of the pressure waves that exit the duct or trench are the duct overpressure (DOP). Distinguishing the IOP and DOP in scale model test data has been difficult in past experiences and in early SMAT results, due to the effects of scaling the geometry. The speed of sound of the air and combustion gas constituents is not scaled, and therefore the SMAT pressure waves propagate at approximately the same speed as occurs in full scale. However, the SMAT geometry is twenty times smaller, allowing the pressure waves to move down the exhaust hole, through the trench and duct, and impact the vehicle model much faster than occurs at full scale. The DOP waves impact portions of the vehicle at the same time as the IOP waves, making it difficult to distinguish the different waves and fully understand the data. To better understand the SMAT data, a computational fluid dynamics (CFD) analysis was performed with a fictitious geometry that isolates the IOP and DOP. The upper and lower portions of the domain were segregated to accomplish the isolation in such a way that the flow physics were not significantly altered. The Loci/CHEM CFD software program was used to perform this analysis.

  6. Pericardial tamponade consequent to a dynamite explosion: blast overpressure injury without penetrating trauma.

    PubMed

    Ozer, Orhan; Sari, Ibrahim; Davutoglu, Vedat; Yildirim, Cuma

    2009-01-01

    Acute cardiac tamponade is a life-threatening emergency that requires prompt treatment by either percutaneous or surgical pericardiocentesis. It may occur after penetrating or blunt chest trauma. We report a case of pericardial tamponade in the absence of penetrating trauma, due to blast overpressure injury after a dynamite explosion-which has not, to our knowledge, been reported before. Physicians should be aware of the possibility of pericardial tamponade in victims of barotraumatic events such as dynamite or bomb explosions, even in the absence of penetrating trauma. Cardiac tamponade, although life-threatening, is easy to treat when recognized.

  7. An improved probit method for assessment of domino effect to chemical process equipment caused by overpressure.

    PubMed

    Mingguang, Zhang; Juncheng, Jiang

    2008-10-30

    Overpressure is one important cause of domino effect in accidents of chemical process equipments. Damage probability and relative threshold value are two necessary parameters in QRA of this phenomenon. Some simple models had been proposed based on scarce data or oversimplified assumption. Hence, more data about damage to chemical process equipments were gathered and analyzed, a quantitative relationship between damage probability and damage degrees of equipment was built, and reliable probit models were developed associated to specific category of chemical process equipments. Finally, the improvements of present models were evidenced through comparison with other models in literatures, taking into account such parameters: consistency between models and data, depth of quantitativeness in QRA.

  8. Effect of fluid overpressure on thrust wedges deformation - insight from sandbox models

    NASA Astrophysics Data System (ADS)

    Pons, A.; Mourgues, R.

    2012-04-01

    Elevated pore pressures are commonly invoked as a key factor for thrust wedges deformation. Even in the well-known and widely used critical taper model of an accretionary wedge, they are introduced as a first-order parameter. This parameter is the Hubbert-Rubey pore pressure ratio λ. Despite the fact that the importance of fluid overpressure is not discussed and that more and more field measurements focus on quantifying pressure distributions, either numerical or analogue modelers are a few to take into account fluid pressure in their modeling. In the critical taper model, fluid overpressure reduces frictional resistance at the base and many experimenters used low frictional materials to create basal detachments. But fluid overpressures also act as body forces on the whole wedge in addition to that of gravity and this second effect was never experimentally confirmed. In this work, we performed scaled experiments in which compressed air is used as the pore fluid, to understand how fluid pressure controls the first stages of thrusting. The models were built with non-cohesive sand in their upper part and glass microbeads for the décollement to insure the weakness of the detachment. Both materials have similar permeabilities and as we applied horizontally varying fluid pressureat the base of the model, the pore pressure ratio λ was almost constant in the whole wedge. We found a good match with the critical taper model predictions. Combining these experiments with an optical image correlation technique (particle imaging velocimetry - PIV), we were able to follow the strain in the model during the entire duration of the shortening. In particular, we studied the propagation of the décollement and highlighted a strong influence of the pressure ratio, λ, on the activation rate of the décollement. Indeed, higher the overpressure is, faster the propagation of the décollement is. Moreover, we found that the distance to the critical taper condition, which depends on both

  9. Far Field Overpressure from TNT Explosions: A Survey of Available Models.

    DTIC Science & Technology

    1981-04-01

    distances from TNT explosions are surveyed. Analytical and empirical models are discussed. DD , iOR,, 1473 ITIO OF INOVS S IS 0SSOLErTE UNCLASSIFIED S/N...34’\\(1) F 1/3 a / where P overpressure P a absolute atmospheric pressure R =distance W = energy released by detonation of the explosive charge, usually...is typical of the analytically based models. Calculations were carried out for three cases: a nuclear blast wave in ideal air, a nuclear blast wave

  10. Blast Overpressure Studies with Animals and Man: Biological Response to Complex Blast Waves

    DTIC Science & Technology

    1993-10-31

    enclosure produce lung injury in rabbits at one -fifth the peak overpressure required for a simple wave. 2 It was suggested that the frequency content of the...Whereas i the lung hemorrhage was confined to the right lung exclusively in the sheep exposed right-side- on to the explosion outdoors in the 3 4I U...to 4.88 x 3.05 x 2.44 m (36.3 m^3), and for D it was 3.05 x 1.52 x 2.44 m (11.3 m^3). A turbine ventilator was mounted on one of I the roof sections

  11. 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)…

  12. 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)…

  13. The vacuum system of IHI's compact SOR ``LUNA''

    NASA Astrophysics Data System (ADS)

    Oishi, M.; Uesaka, M.; Mandai, S.; Nishidono, T.; Nakashizu, T.; Hoshi, Y.

    1991-08-01

    The construction of the 800 MeV compact synchrotron light sources ``LUNA'' was completed in April 1989 at Tsuchiura Facility of IHI. 20 mA beam have been successfully accelerated up to 800 MeV and accumulated with the lifetime of more than 30 min. Now, the machine study and modifications are being done in order to get more accumulated beam currents and longer lifetime. In most of vacuum sections, the static vacuum pressure of less than 1x10E-7 Pa has been obtained and in the presence of synchrotron radiation, the vacuum pressure is measured as less than 1x10E-6 Pa. The SUS316L vacuum chambers were baked at 200 C For 70 hours in total. The surfaces of the vacuum chambers were treated with buff polishing, acid and freon flashing cleaning. In the 23 meters long vacuum system, ten 400 liter/sec ion pumps and 15 cartridge type nonevaporable getter (NEG) pumps are installed and the total vacuum pumping capacity is 6660 liter/sec. Additional, the beam channels for X-ray lithography and other experiments are going to be constructed in 1991.

  14. In-vacuum Faraday isolation remote tuning.

    PubMed

    Accadia, T; Acernese, F; Antonucci, F; Aoudia, S; Arun, K G; Astone, P; Ballardin, G; Barone, F; Barsuglia, M; Bauer, Th S; Beker, M G; Bigotta, S; Birindelli, S; Bitossi, M; Bizouard, M A; Blom, M; Boccara, C; Bondu, F; Bonelli, L; Bosi, L; Braccini, S; Bradaschia, C; Brillet, A; Brisson; Budzynski, R; Bulik, T; Bulten, H J; Buskulic, D; Cagnoli, G; Calloni, E; Campagna, E; Canuel, B; Carbognani, F; Cavalier, F; Cavalieri, R; Cella, G; Cesarini, E; Chassande-Mottin, E; Chincarini, A; Cleva, F; Coccia, E; Colacino, C N; Colas, J; Colla, A; Colombini, M; Corda, C; Corsi, A; Coulon, J-P; Cuoco, E; D'Antonio, S; Dari, A; Dattilo, V; Davier, M; Day, R; De Rosa, R; del Prete, M; Di Fiore, L; Di Lieto, A; Emilio, M Di Paolo; Di Virgilio, A; Dietz, A; Drago, M; Fafone, V; Ferrante, I; Fidecaro, F; Fiori, I; Flaminio, R; Fournier, J-D; Franc, J; Frasca, S; Frasconi, F; Freise, A; Gammaitoni, L; Garufi, F; Gemme, G; Genin, E; Gennai, A; Giazotto, A; Gouaty, R; Granata, M; Greverie, C; Guidi, G M; Heitmann, H; Hello, P; Hild, S; Huet, D; Jaranowski, P; Kowalska, I; Królak, A; La Penna, P; Leroy, N; Letendre, N; Li, T G F; Lorenzini, M; Loriette, V; Losurdo, G; Mackowski, J M; Majorana, E; Man, N; Mantovani, M; Marchesoni, F; Marion, F; Marque, J; Martelli, F; Masserot, A; Michel, C; Milano, L; Minenkov, Y; Mohan, M; Moreau, J; Morgado, N; Morgia, A; Mosca, S; Moscatelli, V; Mours, B; Neri, I; Nocera, F; Pagliaroli, G; Palladino, L; Palomba, C; Paoletti, F; Pardi, S; Parisi, M; Pasqualetti, A; Passaquieti, R; Passuello, D; Persichetti, G; Pichot, M; Piergiovanni, F; Pietka, M; Pinard, L; Poggiani, R; Prato, M; Prodi, G A; Punturo, M; Puppo, P; Rabaste, O; Rabeling, D S; Rapagnani, P; Re, V; Regimbau, T; Ricci, F; Robinet, F; Rocchi, A; Rolland, L; Romano, R; Rosińska, D; Ruggi, P; Sassolas, B; Sentenac, D; Sturani, R; Swinkels, B; Toncelli, A; Tonelli, M; Tournefier, E; Travasso, F; Trummer, J; Vajentei, G; van den Brand, J F J; van der Putten, S; Vavoulidis, M; Vedovato, G; Verkindt, D; Vetrano, F; Viceré, A; Vinet, J-Y; Vocca, H; Was, M; Yvert, M

    2010-09-01

    In-vacuum Faraday isolators (FIs) are used in gravitational wave interferometers to prevent the disturbance caused by light reflected back to the input port from the interferometer itself. The efficiency of the optical isolation is becoming more critical with the increase of laser input power. An in-vacuum FI, used in a gravitational wave experiment (Virgo), has a 20 mm clear aperture and is illuminated by an almost 20 W incoming beam, having a diameter of about 5 mm. When going in vacuum at 10(-6) mbar, a degradation of the isolation exceeding 10 dB was observed. A remotely controlled system using a motorized lambda=2 waveplate inserted between the first polarizer and the Faraday rotator has proven its capability to restore the optical isolation to a value close to the one set up in air.

  15. Microfabricated triggered vacuum switch

    DOEpatents

    Roesler, Alexander W.; Schare, Joshua M.; Bunch, Kyle

    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.

  16. ELETTRA vacuum system

    NASA Astrophysics Data System (ADS)

    Bernardini, M.

    1991-08-01

    A status report of the vacuum system of ELETTRA, the 2 GeV, 400 mA light source under construction in Trieste, will be described. The Vacuum project, presented at ``Synchrotron Radiation Vacuum Workshop'' at Riken (Japan 22-24 March 1990) and more recently at EVC-2, the European Vacuum Conference at Trieste (Italy 21-26 May 1990), is now in the phase of testing a prototype sector, which is 1/24 of the ring circumference. Details and some technological aspects of the fabrication will be reviewed together with the vacuum performances. Results of laboratory experiments on components, standard or not, allowed us to finalize the main choices in light of the general philosophy of the project and will be properly summarized.

  17. Cervical spine annulus vacuum.

    PubMed

    Bohrer, S P; Chen, Y M

    1988-01-01

    Thirty-eight annulus vacuums in 27 patients were analyzed with regard to location, configuration, and associated vertebral abnormalities such as degenerative changes, absent and compressed anterosuperior vertebral body corners, and annulus calcification. It is concluded that most annulus vacuums are a degenerative phenomenon at the attachment of the annulus to bone. These vacuums may be associated with other degenerative changes such as osteophytes and annulus calcification. Vacuums have a strong association with compressed anterosuperior corners. These deformed corners are thought to be early osteophytes and may be related to previous trauma, a vertebra with an absent corner, and/or normal motion. Small annulus vacuums adjacent to vertebral corners with a normal appearance are more likely to result from acute trauma.

  18. Vacuum tunneling in gravity

    NASA Astrophysics Data System (ADS)

    Cho, Y. M.; Pak, D. G.

    2011-08-01

    Topologically non-trivial vacuum structures in gravity models with Cartan variables (vielbein and contortion) are considered. We study the possibility of vacuum spacetime tunneling in Einstein gravity assuming that the vielbein may play a fundamental role in quantum gravitational phenomena. It has been shown that in the case of RP3 space topology, the tunneling between non-trivial topological vacuums can be realized by means of Eguchi-Hanson gravitational instanton. In the Riemann-Cartan geometric approach to quantum gravity, the vacuum tunneling can be provided by means of contortion quantum fluctuations. We define a double self-duality condition for the contortion and give explicit self-dual configurations which can contribute to vacuum tunneling amplitude.

  19. An integrated wire harp and readout electronics inside vacuum

    SciTech Connect

    Chatterjee, Mou; Nabhiraj, P. Y.

    2015-03-15

    A wire harp is a well known instrument used in ion beam profile measurement and beam diagnostics. Till date, for beam instrumentation, the harp is placed inside the vacuum chamber or beam line in direct exposure to the beam profile to be measured, whereas the related readout electronics is placed outside somewhere at a convenient place. Here, a harp has been developed along with the readout electronics as an integrated part of it and both were placed inside the beam line vacuum (order of 10{sup −7} Torr) to make the system much simpler, easy to operate, and measure small beam current more accurately. The entire signal conversion and processing is done inside the vacuum unlike other systems; hence, the electronics is kept inside. This results in a lesser number (only 4 pin) of electrical connections (feedthrough) including power which otherwise would have required 32 feedthrough pins only for signal readout for a 13 × 13 (X × Y) channel harp. This paper describes a completely new approach to the design of a conventional beam harp widely used for beam instrumentation.

  20. An integrated wire harp and readout electronics inside vacuum

    NASA Astrophysics Data System (ADS)

    Chatterjee, Mou; Nabhiraj, P. Y.

    2015-03-01

    A wire harp is a well known instrument used in ion beam profile measurement and beam diagnostics. Till date, for beam instrumentation, the harp is placed inside the vacuum chamber or beam line in direct exposure to the beam profile to be measured, whereas the related readout electronics is placed outside somewhere at a convenient place. Here, a harp has been developed along with the readout electronics as an integrated part of it and both were placed inside the beam line vacuum (order of 10-7 Torr) to make the system much simpler, easy to operate, and measure small beam current more accurately. The entire signal conversion and processing is done inside the vacuum unlike other systems; hence, the electronics is kept inside. This results in a lesser number (only 4 pin) of electrical connections (feedthrough) including power which otherwise would have required 32 feedthrough pins only for signal readout for a 13 × 13 (X × Y) channel harp. This paper describes a completely new approach to the design of a conventional beam harp widely used for beam instrumentation.

  1. An integrated wire harp and readout electronics inside vacuum.

    PubMed

    Chatterjee, Mou; Nabhiraj, P Y

    2015-03-01

    A wire harp is a well known instrument used in ion beam profile measurement and beam diagnostics. Till date, for beam instrumentation, the harp is placed inside the vacuum chamber or beam line in direct exposure to the beam profile to be measured, whereas the related readout electronics is placed outside somewhere at a convenient place. Here, a harp has been developed along with the readout electronics as an integrated part of it and both were placed inside the beam line vacuum (order of 10(-7) Torr) to make the system much simpler, easy to operate, and measure small beam current more accurately. The entire signal conversion and processing is done inside the vacuum unlike other systems; hence, the electronics is kept inside. This results in a lesser number (only 4 pin) of electrical connections (feedthrough) including power which otherwise would have required 32 feedthrough pins only for signal readout for a 13 × 13 (X × Y) channel harp. This paper describes a completely new approach to the design of a conventional beam harp widely used for beam instrumentation.

  2. Design of the EBIS vacuum system

    SciTech Connect

    Mapes, M.; Smart, L.; Weiss, D.

    2011-03-28

    At Brookhaven National Laboratory the Electron Beam Ion Source (EBIS) is presently being commissioned. The EBIS will be a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC). The new preinjector has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium. The background pressure in the ionization region of the EBIS required to be low enough that it does not produce a significant number of ions from background gas. The pressure in the regions of the electron gun and electron collector can be higher than in the ionization region provided there is efficient vacuum separation between the sections. For injection the ions must be accelerated to 100KV by pulsing the EBIS platform. All associated equipment including the vacuum equipment on the platform is at a 100KV potential. The vacuum system design and the vacuum controls for the EBIS platform and transport system will be presented as well as the interface with the Booster Ring which has a pressure 10-11 Torr.

  3. Pseudo ribbon metal ion beam source

    SciTech Connect

    Stepanov, Igor B. Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-02-15

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  4. Component Overpressure Growth and Characterization of High Resistivity CdTe Crystals for Radiation Detectors

    SciTech Connect

    Mandal, Krishna; Kang, Sung Hoon; Choi, Michael; Wei, Jiuan; Zheng, Lili; Zhang, Hui; Jellison Jr, Gerald Earle; Groza, Michael; Burger, Arnold

    2007-01-01

    Spectrometer-grade CdTe single crystals with resistivities higher than 10{sup 9} {Omega} cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties ({mu}{tau}{sub e} = 2 x 10{sup -3} cm{sup 2} V{sup -1}, {mu}{tau}{sub h} = 8 x 10{sup -5} cm{sup 2} V{sup -1}) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55'), 38 mm (1.5'), and 76 mm (3'). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using {sup 241}Am (60 keV) and {sup 137}Cs (662 keV) sources are presented.

  5. The roles of foam ceramics in suppression of gas explosion overpressure and quenching of flame propagation.

    PubMed

    Nie, Baisheng; He, Xueqiu; Zhang, Ruming; Chen, Wenxue; Zhang, Jinfeng

    2011-08-30

    In order to substantially suppress the shock waves resulting from gas explosions in coal mines as well as to reveal the mechanism of explosion flame quenching by foam ceramics, a rectangular explosion test pipe was designed, which has a 200mm × 200mm cross-section and is similar in shape to the roadways in coal mines. Explosion flame propagation characteristics in empty pipe and in the presence of Al(2)O(3) and SiC foam ceramics were experimentally investigated. To obtain direct observations, the flame propagation was photographed by a high-speed camera. Furthermore, the mechanism of foam ceramics affecting gas explosion propagation was analyzed. The results demonstrate that the foam ceramics attenuate drastically the maximal explosion overpressure by up to fifty percent; the interconnected micro-network structure of the foam ceramics contribute to quenching gas explosion flame and suppressing shock wave overpressure. These important findings hint that, if properly designed and deployed, this material is expected to be developed into a new suppression and isolation technique against multiple and continuous gas explosions that are presently a grave threat to production safety of coal mines across China and the rest of the world. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Nozzle Exit Over-Pressure and Vortex Ring Interaction in a Fully-Pulsed Jet

    NASA Astrophysics Data System (ADS)

    Krueger, Paul S.; Gharib, Morteza

    2002-11-01

    Vortex rings formed by a starting jets will stop entraining circulation and pinch off from their generating or "trailing" jet for sufficiently large piston stroke length to jet diameter ratios (L/D) [Gharib et. al., JFM, 1998]. Recent work by the authors has demonstrated that the leading vortex ring contributes more impulse per unit L/D than does the trailing jet, highlighting the significance of vortex ring pinch off for propulsive applications. The impulse advantage of the leading vortex ring is provided by nozzle exit over-pressure resulting from the acceleration of ambient fluid during ring formation. The present work extends these single-pulse results to a periodic series of starting jets, i.e., a fully-pulsed jet. Measurements were made of the time-averaged thrust of fully-pulsed jets generated using a piston-cylinder mechanism for 2 < L/D < 6 and a range of pulsing frequencies. The results indicate that vortex ring formation provides substantial nozzle exit over-pressure (and hence, thrust benefit) in the pulsed case as well, but the benefit tends to diminish with increasing frequency. Various vortex ring interactions contribute to this trend.

  7. Explosion overpressure test series: General-Purpose Heat Source development: Safety Verification Test program

    SciTech Connect

    Cull, T.A.; George, T.G.; Pavone, D.

    1986-09-01

    The General-Purpose Heat Source (GPHS) is a modular, radioisotope heat source that will be used in radioisotope thermoelectric generators (RTGs) to supply electric power for space missions. The first two uses will be the NASA Galileo and the ESA Ulysses missions. The RTG for these missions will contain 18 GPHS modules, each of which contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W/sub (t)/. A series of Safety Verification Tests (SVTs) was conducted to assess the ability of the GPHS modules to contain the plutonia in accident environments. Because a launch pad or postlaunch explosion of the Space Transportation System vehicle (space shuttle) is a conceivable accident, the SVT plan included a series of tests that simulated the overpressure exposure the RTG and GPHS modules could experience in such an event. Results of these tests, in which we used depleted UO/sub 2/ as a fuel simulant, suggest that exposure to overpressures as high as 15.2 MPa (2200 psi), without subsequent impact, does not result in a release of fuel.

  8. Evaluation of overpressure prediction models for air blast above the triple point.

    PubMed

    Ehrhardt, L; Boutillier, J; Magnan, P; Deck, C; De Mezzo, S; Willinger, R; Cheinet, S

    2016-07-05

    The increase of blast exposures leads to the need for better assessment of the blast threat. Empirical models describing the blast propagation in ideal conditions as free-field or surface detonations are commonly employed, but in some configurations the ground-reflected shock should be treated explicitly. Empirical models permit the prediction of the blast characteristics with the ground-reflected shock. The present study uses some original experimental data to evaluate the accuracy of the predicted overpressure with time regarding the reflected shock characteristics. Three methods are tested. The first method, called method of images (MOI) and linearly adding a virtual ground-symmetrical source blast to the free-field blast, is quick but lacks accuracy regarding the reflected shock characteristics. The second method, based on the LOAD_BLAST_ENHANCED function of the commercial LS-DYNA framework, better captures the reflected shock compared to the MOI, but the overall differences with experimental data are of the same order of magnitude as for the MOI. An original fit is introduced, based on standard physical parameters. The accuracy of this fit on the reflected shock characteristics, and the better match with the overall overpressure time series, shows its potential as a new empirical blast predicting tool. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Role of fluid overpressures in controlling the form of crustal strength-depth profiles

    NASA Astrophysics Data System (ADS)

    Suppe, John

    2015-04-01

    The classic crustal strength-depth model of Brace and Kolhstedt (1980) based on experimental rock mechanics depends in the brittle regime on the assumption of linearly increasing hydrostatic pore-fluid pressures. This leads to a predicted linearly increasing brittle strength that is well established based on deep borehole stress measurements in crystalline crust. In contrast, fluid overpressures are widely documented in orogenic belts based on borehole data, seismic velocity analysis, modeling of seismic tremors, and analysis of veins, which in some cases show complex fault-valve pressure fluctuations between lithostatic and hydrostatic. Typical observed overpressure-depth relationships show approximately constant effective stress and therefore a pressure-dependent crustal strength that is approximately constant with depth in contrast with the classic model. This constant-strength behavior below the fluid-retention depth ZFRDhas been confirmed using deep borehole stress and fluid-pressure measurements (Suppe, 2014). The pressure-dependent strength magnitude is the strength at the fluid-retention depth, which is commonly ~50MPa or less because ZFRD is typically

  10. APS storage ring vacuum system performance

    SciTech Connect

    Noonan, J.R.; Gagliano, J.; Goeppner, G.A.

    1997-06-01

    The Advanced Photon Source (APS) storage ring was designed to operated with 7-GeV, 100-mA positron beam with lifetimes > 20 hours. The lifetime is limited by residual gas scattering and Touschek scattering at this time. Photon-stimulated desorption and microwave power in the rf cavities are the main gas loads. Comparison of actual system gas loads and design calculations will be given. In addition, several special features of the storage ring vacuum system will be presented.

  11. Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring

    SciTech Connect

    Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G.; Singh, P.

    2013-12-15

    In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

  12. TRIUMF cyclotron vacuum system refurbishing

    NASA Astrophysics Data System (ADS)

    Sekachev, I.

    2008-03-01

    The cyclotron at TRIUMF was commissioned to full energy in 1974. The volume of the cyclotron vacuum tank is about 100 m3 and it operates at 5×10-8 Torr pressure during beam production. The pumping is mainly based on a Phillips B-20 cryogenerator (Stirling cycle 4-cylinder engine). The cryogenerator supplies helium gas at 16 K and 70 K to cryopanels in the tank. The decreasing reliability of the B-20 and demanding maintenance requirements triggered the decision to completely overhaul or replace the cryogenerator. Replacement with the LINDE-1630 helium refrigerator was found to be the most attractive (technically and economically) option. The details of the proposal with installation of the helium refrigerator and with a continuous flow liquid nitrogen shield cooling system are presented.

  13. Laser sealed vacuum insulation window

    DOEpatents

    Benson, David K.; Tracy, C. Edwin

    1987-01-01

    A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the glass panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

  14. Laser sealed vacuum insulating window

    DOEpatents

    Benson, D.K.; Tracy, C.E.

    1985-08-19

    A laser sealed evacuated window panel is comprised of two glass panes held spaced apart in relation to each other by a plurality of spherical glass beads and glass welded around the edges to provide an evacuated space between the glass panes that is completely glass sealed from the exterior. The glass welded edge seal is obtained by welding the edges of the glass panes together with a laser beam while the glass panes and bead spacers are positioned in a vacuum furnace and heated to the annealing point of the glass to avoid stress fracture in the area of the glass weld. The laser welding in the furnace can be directed around the perimeter of the galss panel by a combination of rotating the glass panel and linearly translating or aiming the laser with a relay mirror.

  15. Thermophoretic vacuum wand

    DOEpatents

    Klebanoff, Leonard Elliott; Rader, Daniel John

    2001-01-01

    A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

  16. Thermophoretic vacuum wand

    DOEpatents

    Klebanoff, Leonard Elliott; Rader, Daniel John

    2000-01-01

    A thermophoretic vacuum wand that is particularly suited for transporting articles in a cleanroom environment so that potential particle contaminants in the air do not become adhered to the surface of the article is described. The wand includes a housing having a platen with a front surface with suction port(s) through the platen; a vacuum source for applying a negative pressure to the suction port(s); and heating device for the object. Heating the article when it is held by the vacuum wand affords thermophoretic protection that effectively prevents particles in the air from depositing onto the article.

  17. National Synchrotron Light Source II storage ring vacuum systems

    SciTech Connect

    Hseuh, Hsiao-Chaun; Hetzel, Charles; Leng, Shuwei; Wilson, King; Xu, Huijuan; Zigrosser, Douglas

    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, this 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.

  18. 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

  19. National Synchrotron Light Source II storage ring vacuum systems

    SciTech Connect

    Hseuh, Hsiao-Chaun Hetzel, Charles; Leng, Shuwei; Wilson, King; Xu, Huijuan; Zigrosser, Douglas

    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 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.

  20. Beam ion instability: Measurement, analysis, and simulation

    SciTech Connect

    Wang, L.; Safranek, J.; Cai, Y.; Corbett, J.; Hettel, B.; Raubenheimer, T. O.; Schmerge, J.; Sebek, J.; /SLAC

    2013-10-03

    A weak vertical coupled-bunch instability with oscillation amplitude of the order of a few μ m has been observed in SPEAR3 at nominal vacuum pressure. The instability becomes stronger with increasing neutral gas pressure as observed by turning off vacuum pumps, and becomes weaker when the vertical beam emittance is increased. These observations indicate that the vertical beam motion is driven by ions trapped in the periodic potential of the electron beam. In this paper we present a series of comprehensive beam measurements, impedance-based stability analysis, and numerical simulations of beam-ion interactions in SPEAR3. The effects of vacuum pressure, gas species, beam current, bunch fill pattern, chromaticity, and vertical beam emittance are investigated.

  1. Collapse of vacuum bubbles in a vacuum

    NASA Astrophysics Data System (ADS)

    Ng, Kin-Wang; Wang, Shang-Yung

    2011-02-01

    We revisit the dynamics of a false vacuum bubble in a background de Sitter spacetime. We find that there exists a large parameter space that allows the bubble to collapse into a black hole or to form a wormhole. This may have interesting implications for the creation of a baby universe in the laboratory, the string landscape where the bubble nucleation takes place among a plenitude of metastable vacua, and the inflationary physics.

  2. Collapse of vacuum bubbles in a vacuum

    SciTech Connect

    Ng, Kin-Wang; Wang, Shang-Yung

    2011-02-15

    We revisit the dynamics of a false vacuum bubble in a background de Sitter spacetime. We find that there exists a large parameter space that allows the bubble to collapse into a black hole or to form a wormhole. This may have interesting implications for the creation of a baby universe in the laboratory, the string landscape where the bubble nucleation takes place among a plenitude of metastable vacua, and the inflationary physics.

  3. Vacuum mechatronics first international workshop

    SciTech Connect

    Belinski, S.E.; Shirazi, M.; Hackwood, S.; Beni, G. )

    1989-01-01

    This report contains papers on the following topics: proposed epitaxial thin film growth in the ultra-vacuum of space; particle monitoring and control in vacuum processing equipment; electrostatic dust collector for use in vacuum systems; materials evaluation of an electrically noisy vacuum slip ring assembly; an overview of lubrication and associated materials for vacuum service; the usage of lubricants in a vacuum environment; guidelines and practical applications for lubrication in vacuum; recent development in leak detector and calibrator designs; the durability of ballscrews for ultrahigh vacuum; vacuum-compatible robot for self-contained manufacturing systems; the design, fabrication, and assembly of an advanced vacuum robotics system for space payload calibration; design criteria for mechanisms used in space; and concepts and requirements for semiconductor multiprocess integration in vacuum. These papers are indexed separately elsewhere.

  4. Vacuum electrospray of volatile liquids assisted by infrared laser irradiation.

    PubMed

    Ninomiya, Satoshi; Chen, Lee Chuin; Suzuki, Hiroaki; Sakai, Yuji; Hiraoka, Kenzo

    2012-04-15

    Current large cluster sources such as C(60) or argon utilize gas-phase sources which are of low-brightness and cannot be focused efficiently to better than 1 micron diameter spot size. The development of a high-brightness large cluster ion source is of critical importance to achieve high resolution in secondary ion mass spectrometry (SIMS) imaging of organics. We propose a new high-brightness large cluster ion source, and a technique for producing a stable electrospray of volatile liquids under vacuum. It is known that vacuum electrospray of volatile liquids such as water is extremely difficult because of freezing of the liquids introduced in vacuum by evaporative cooling. To avoid freezing, the tip of the electrospray emitter was irradiated by a continuous wave infrared laser. Without continuous laser irradiation the vacuum electrospray of a water/methanol solution was unstable with respect to the shapes of the Taylor cone and current, whereas continuous laser irradiation produced a stable electrospray of water. The typical modes of electrospray were clearly observed with an optical microscope even under vacuum conditions. A stable vacuum electrospray could be achieved by improving the vacuum pressure to suppress electric discharge and by using the laser to maintain the liquid state. This is the first description of the production of a stable vacuum electrospray of volatile liquids such as water. This vacuum electrospray technique can be expected to produce a novel high-brightness large cluster ion beam source. Copyright © 2012 John Wiley & Sons, Ltd.

  5. Nitrogen gas propagation in a liquid helium cooled vacuum tube following a sudden vacuum loss

    NASA Astrophysics Data System (ADS)

    Dhuley, R. C.; Van Sciver, S. W.

    2017-02-01

    We present experimental measurements and analysis of propagation of the nitrogen gas that was vented to a high vacuum tube immersed in liquid helium (LHe). The scenario resembles accidental venting of atmospheric air to a SRF beam-line and was investigated to understand how the in-flowing air would propagate in such geometry. The gas front propagation speed in the tube was measured using pressure probes and thermometers installed at regular intervals over the tube length. The experimental data show the front speed to decrease along the vacuum tube. The empirical and analytical models developed to characterize the front deceleration are summarized.

  6. The ultra high vacuum system of the AGS Booster

    SciTech Connect

    Hseuh, H.C.; Sadinsky, S.; Savino, J.; Schnitzenbaumer, P.; Sattel, P.; Van Zwienen, W.; Xiuhua, Cui

    1989-01-01

    The AGS Booster currently under construction at Brookhaven is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of 3 /times/ 10/sup /minus/11/ Torr is required to minimize beam loss of the partially stripped heavy ions. This paper described the design and processing of the ultra high vacuum system, and the performance of the prototype vacuum half cells. 9 refs., 4 figs.

  7. Evidence of muonium formation using thin gold foils in vacuum

    NASA Technical Reports Server (NTRS)

    Barnett, B. A.; Chang, C. Y.; Steinberg, P.; Yodh, G. B.; Orr, H. D.; Carroll, J. B.; Eckhause, M.; Kane, J. R.; Spence, C. B.; Hsieh, C. S.

    1977-01-01

    The production of thermal muonium in a vacuum region has been investigated using an array of 200 thin (about 1000 A thick) gold foils exposed to a stopping positive-muon beam. By examining the observed time dependence of the positive-muon decay spectra in various transverse magnetic field, it is estimated that the lower limit of the probability of muonium formation by these gold foils placed in vacuum was 0.28 plus or minus 0.05.

  8. PEP-II vacuum system pressure profile modeling using EXCEL

    SciTech Connect

    Nordby, M.; Perkins, C.

    1994-06-01

    A generic, adaptable Microsoft EXCEL program to simulate molecular flow in beam line vacuum systems is introduced. Modeling using finite-element approximation of the governing differential equation is discussed, as well as error estimation and program capabilities. The ease of use and flexibility of the spreadsheet-based program is demonstrated. PEP-II vacuum system models are reviewed and compared with analytical models.

  9. The classical vacuum

    NASA Astrophysics Data System (ADS)

    Boyer, T. H.

    1985-08-01

    The history of vacuum concepts is reviewed, noting that no way is known to physically produce a true void. Even at absolute zero, a pattern of electromagnetic wave fluctuations are still present. The fluctuations are called zero-point radiation (ZPR). To be invariant to Lorentz transformation, ZPR has a spectral intensity proportional to the cube of each frequency. ZPR does not change in response to compression and produces a force between objects that is inversely proportional to the 4th power of the separation distance. The ZPR scale value has been measured to be one-half of the Planck constant, and is the measure of the energy of a harmonic oscillator, such as the electron, in a vacuum. Finally, since gravitational accelerations always occur in the physical space, a minimum thermal radiation can also be found for the vacuum, implying that a fixed relationship exists between thermal radiation and the classical vacuum.

  10. Vacuum Camera Cooler

    NASA Technical Reports Server (NTRS)

    Laugen, Geoffrey A.

    2011-01-01

    Acquiring cheap, moving video was impossible in a vacuum environment, due to camera overheating. This overheating is brought on by the lack of cooling media in vacuum. A water-jacketed camera cooler enclosure machined and assembled from copper plate and tube has been developed. The camera cooler (see figure) is cup-shaped and cooled by circulating water or nitrogen gas through copper tubing. The camera, a store-bought "spy type," is not designed to work in a vacuum. With some modifications the unit can be thermally connected when mounted in the cup portion of the camera cooler. The thermal conductivity is provided by copper tape between parts of the camera and the cooled enclosure. During initial testing of the demonstration unit, the camera cooler kept the CPU (central processing unit) of this video camera at operating temperature. This development allowed video recording of an in-progress test, within a vacuum environment.

  11. Welding space vacuum technology

    NASA Technical Reports Server (NTRS)

    Johnson, R. Barry

    1991-01-01

    The objective was to assist the EH 42 Division in putting together a vacuum system that could attain the desired pressure and be large enough to accommodate the gas-metal arc (GMA) welding fixture apparatus. A major accomplishment was the design and fabrication of the controller/annunciator for the 4' by 8' system. It contains many safety features such as thermocouple set point relays that will only allow inlet and exit gas and vacuum valves to be operated at pre-selected system pressures, and a fail safe mode for power interruptions and operator mistakes. It is felt that significant progress was made in this research effort to weld in a vacuum environment. With continued efforts to increase the pump speeds for vacuum chambers and further studies on weld fixtures and gas inlet pressures, the NASA program will be successful.

  12. TFTR diagnostic vacuum controller

    SciTech Connect

    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.

  13. Vacuum self-magnetization?

    SciTech Connect

    Perez Rojas, H.; Rodriguez Querts, E.

    2006-06-19

    We study vacuum properties in a strong magnetic field as the zero temperature and zero density limit of quantum statistics. For charged vector bosons (W bosons) the vacuum energy density diverges for B > B{sub c} = m{sub w}{sup 2}/e, leading to vacuum instability. A logarithmic divergence of vacuum magnetization is found for B = Bc, which suggests that if the magnetic field is large enough, it is self-consistently maintained, and this mechanism actually prevents B from reaching the critical value Bc. For virtual neutral vector bosons bearing an anomalous magnetic moment, the instability of the ground state for B > B{sub c}{sup '} = m{sub n}{sup 2}/q also leads to the vacuum energy density divergence for fields B > B{sub c}{sup '} and to the magnetization divergence for B B{sub c}{sup '}. The possibility of virtual electron-positron pairs bosonization in strong magnetic field and the applicability of the neutral bosons model to describe the virtual positronium behavior in a magnetic field are discussed. We conjecture that this could lead to vacuum self-magnetization in QED.

  14. Ultra-high vacuum in superconducting accelerator rings

    NASA Astrophysics Data System (ADS)

    Bazanov, A. M.; Butenko, A. V.; Galimov, A. R.; Lugovnin, A. K.; Smirnov, A. V.

    2016-12-01

    Achieving the ultra-high vacuum (UHV) in the collider and booster of the NICA project is one of the main challenges when creating this device. It determines the need for a serious approach to this issue and conducting research in this direction. First, it is necessary to understand the effect of the various components of the vacuum systems on the degree of vacuum. It is also necessary to carry out studies of pumping devices for producing the required vacuum (10-9 Pa) in the beam chamber and choose the most optimal pumping scheme. At the same time, it is necessary to figure out how various operations are carried out with the vacuum chamber: preparation of vacuum surfaces, letting in the atmosphere, and warming the chamber after closing the influence on the degree of vacuum and the composition of the residual gas. The temperature may vary from room temperature to liquid helium temperature due to the difficulty of keeping the beam-chamber walls at a constant temperature, including the inner components. This complicates the processes taking place within it. Additional complexity arises due the heating of the chamber walls by various processes during the operation of the accelerator (for example, cycling the magnetic field).

  15. Simulation studies of vacuum system for Indus-2

    NASA Astrophysics Data System (ADS)

    Shukla, S. K.; Kotaiah, S.

    2008-05-01

    Due to eight fold symmetry of lattice, the 172.4 meters circumference of Indus-2 was divided into eight unit cells. The location of vacuum pumps was restricted by location of more important components like magnets, beam diagnostic components etc. The minimum permissible beam aperture, restricted by apertures of magnets, rendered the vacuum envelope highly conductance limited. Main sources of gas loads viz the outgassing and the photon induced desorption (PID) were also highly location specific, because of location of photon absorbers, and the specific nature of vacuum components. Therefore, the computer simulation of a unit cell was important to have a feel for ultimate results obtained by a particular configuration of pump installation. The vacuum system for a unit cell was studied using electrical equivalent network for the vacuum system. The entire circuit was analyzed by using commercial software used for electronics circuit analysis. Since the synchrotron radiation leads to cleaning effect and the PID yield reduces with accumulated dose of beam current, system's behaviour with beam current was also studied by using computer program obtained from BESSY Berlin. This provided an estimate of dose necessary for achieving the specified operation of UHV system for Indus-2. The calculations also helped in optimizing the initial cleaning of chambers by glow discharge cleaning etc. This paper presents the results obtained by computer simulations of a unit cell of Indus-2, carried out by both the methods.

  16. Altered gene expression in cultured microglia in response to simulated blast overpressure: possible role of pulse duration.

    PubMed

    Kane, Michael J; Angoa-Pérez, Mariana; Francescutti, Dina M; Sykes, Catherine E; Briggs, Denise I; Leung, Lai Yee; VandeVord, Pamela J; Kuhn, Donald M

    2012-07-26

    Blast overpressure has long been known to cause barotrauma to air-filled organs such as lung and middle ear. However, experience in Iraq and Afghanistan is revealing that individuals exposed to explosive munitions can also suffer traumatic brain injury (TBI) even in the absence of obvious external injury. The interaction of a blast shock wave with the brain in the intact cranial vault is extremely complex making it difficult to conclude that a blast wave interacts in a direct manner with the brain to cause injury. In an attempt to "isolate" the shock wave and test its primary effects on cells, we exposed cultured microglia to simulated blast overpressure in a barochamber. Overpressures ranging from 15 to 45 psi did not change microglial Cox-2 levels or TNF-α secretion nor did they cause cell damage. Microarray analysis revealed increases in expression of a number of microglial genes relating to immune function and inflammatory responses to include Saa3, Irg1, Fas and CxCl10. All changes in gene expression were dependent on pulse duration and were independent of pressure. These results indicate that microglia are mildly activated by blast overpressure and uncover a heretofore undocumented role for pulse duration in this process.

  17. Altered Gene Expression in Cultured Microglia in Response to Simulated Blast Overpressure: Possible Role of Pulse Duration

    PubMed Central

    Kane, Michael J.; Angoa-Pérez, Mariana; Francescutti, Dina M.; Sykes, Catherine E.; Briggs, Denise I.; Leung, Lai Yee; VandeVord, Pamela J.; Kuhn, Donald M.

    2012-01-01

    Blast overpressure has long been known to cause barotrauma to air-filled organs such as lung and middle ear. However, experience in Iraq and Afghanistan is revealing that individuals exposed to explosive munitions can also suffer traumatic brain injury (TBI) even in the absence of obvious external injury. The interaction of a blast shock wave with the brain in the intact cranial vault is extremely complex making it difficult to conclude that a blast wave interacts in a direct manner with the brain to cause injury. In an attempt to “isolate” the shock wave and test its primary effects on cells, we exposed cultured microglia to simulated blast overpressure in a barochamber. Overpressures ranging from 15–45 psi did not change microglial Cox-2 levels or TNF-α secretion nor did they cause cell damage. Microarray analysis revealed increases in expression of a number of microglial genes relating to immune function and inflammatory responses to include Saa3, Irg1, Fas and CxCl10. All changes in gene expression were dependent on pulse duration and were independent of pressure. These results indicate that microglia are mildly activated by blast overpressure and uncover a heretofore undocumented role for pulse duration in this process. PMID:22698585

  18. Suppressed vitrinite reflectance in the Ferron coalbed gas fairway, central Utah: Possible influence of overpressure

    USGS Publications Warehouse

    Quick, J.C.; Tabet, D.E.

    2003-01-01

    Chemical and thermoplastic properties of coals in the Ferron coalbed methane fairway indicate that coals in the north are of higher rank than coals in the south. Measured vitrinite reflectance does not accurately show this variation of coal rank. Although vitrinite reflectance in the southern and central part of the fairway is consistent with other measures of coal rank, suppressed vitrinite reflectance is observed in the north where methane contents are relatively high. This coincidence of suppressed reflectance and relatively high coalbed methane yields may be significant. We speculate that the suppressed reflectance values result from a burial history where overpressure developed during the early stages of coalification and persisted until recent uplift and cooling; such instances may be diagnostic of prospective coalbed methane targets elsewhere. ?? 2003 Published by Elsevier B.V.

  19. Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

    SciTech Connect

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; Malinverno, Alberto

    2016-08-31

    Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Here, short-range advective migration can increase the amount of methane delivered to sands as compared to the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.

  20. Tectonic overpressure may reconcile the structural and petrological records of the Adula nappe (Central Alps)

    NASA Astrophysics Data System (ADS)

    Pleuger, Jan; Podladchikov, Yuri

    2014-05-01

    accordance with the structural record, the Adula nappe can be restored to maximum depths of up to ca. 60 km. For individual points of the Adula nappe in the restored cross section, corresponding to the sporadic occurences of (ultra)high-pressure rocks, lithostatic pressures are exceeded by petrological peak-pressure data by about 40% to 80%. Such amounts of tectonic overpressure are within the limits of theoretical considerations and numerical modelling results. For the other units comprised in the cross section, and for subsequent tectono-metamorphic stages of the Adula nappe, negligible amounts of overpressure (around 10%) are determined from the restoration. We conclude that (1) the NFP20-East cross section can be kinematically restored by using only structural data, (2) the dilemma mentioned above can be solved by admitting realisting amounts of tectonic overpressure, and (3) significant amounts of overpressure were established only locally and episodically.

  1. Blast traumatic brain injury in the rat using a blast overpressure model.

    PubMed

    Yarnell, Angela M; Shaughness, Michael C; Barry, Erin S; Ahlers, Stephen T; McCarron, Richard M; Grunberg, Neil E

    2013-01-01

    Traumatic brain injury (TBI) is a serious health concern for civilians and military populations, and blast-induced TBI (bTBI) has become an increasing problem for military personnel over the past 10 years. To understand the biological and psychological effects of blast-induced injuries and to examine potential interventions that may help to prevent, attenuate, and treat effects of bTBI, it is valuable to conduct controlled animal experiments. This unit discusses available paradigms to model traumatic brain injury in animals, with an emphasis on the relevance of these various models to study blast-induced traumatic brain injury (bTBI). This paper describes the detailed methods of a blast overpressure (BOP) paradigm that has been used to conduct experiments with rats to model blast exposure. This particular paradigm models the pressure wave created by explosions, including improvised explosive devices (IEDs).

  2. Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

    DOE PAGES

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; ...

    2016-08-31

    Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Here, short-range advective migration can increase the amount of methane delivered to sands as compared tomore » the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.« less

  3. Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

    SciTech Connect

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; Malinverno, Alberto

    2016-08-31

    Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Here, short-range advective migration can increase the amount of methane delivered to sands as compared to the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.

  4. Short-range, overpressure-driven methane migration in coarse-grained gas hydrate reservoirs

    NASA Astrophysics Data System (ADS)

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; Malinverno, Alberto

    2016-09-01

    Two methane migration mechanisms have been proposed for coarse-grained gas hydrate reservoirs: short-range diffusive gas migration and long-range advective fluid transport from depth. Herein, we demonstrate that short-range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse-grained hydrate reservoirs. Two-dimensional simulations demonstrate that this migration mechanism, short-range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end-member mechanisms. Short-range advective migration can increase the amount of methane delivered to sands as compared to the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.

  5. A study of the safety of the ASTM D5304 oxygen overpressure stability test

    SciTech Connect

    White, E.W.; Flohr, K.W.

    1995-04-01

    While the test method for assessing distillate fuel storage stability by oxygen overpressure was being evaluated as a potential ASTM standard, a question of its safety was raised, specifically whether the juxta-position of liquid fuel and oxygen at elevated pressure could lead to explosive self ignition. As a consequence, the authors conducted a literature search followed by a small experimental program. The results of those studies show that the temperature and pressure used in Test Method D5304 are probably safely below the conditions that would lead to autoignition of normal middle distillate fuels. However, middle distillate fuels of unknown or unusual sources, or containing additives, e.g. ignition improvers, should be screened before evaluating their stability by Test Method D5304.

  6. Effect of preliminary vacuum plasma treatment on coating adhesion

    NASA Astrophysics Data System (ADS)

    Slabodchikov, Vladimir A.; Borisov, Dmitry P.; Kuznetsov, Vladimir M.

    2016-11-01

    The paper presents research results on the adhesion properties of Si coatings synthesized by different methods and under different conditions of preliminary vacuum ion plasma treatment of substrates with subsequent magnetron sputtering. The substrate surface was pretreated with low-energy ion beams, high-energy ion beams, gas discharge plasma, and plasma produced by a magnetron sputtering system. The vacuum conditions (pump type, pressure, etc.), the ion current density, and the bias parameters (pulse repetition frequency and duration) were varied. The research results demonstrate a considerable effect of plasma immersion ion implantation on the adhesion of Si coatings to NiTi substrates.

  7. Overpressure and hydrocarbon accumulations in Tertiary strata, Gulf Coast of Louisiana

    USGS Publications Warehouse

    Nelson, Philip H.

    2012-01-01

    Many oil and gas reservoirs in Tertiary strata of southern Louisiana are located close to the interface between a sand-rich, normally pressured sequence and an underlying sand-poor, overpressured sequence. This association, recognized for many years by Gulf Coast explorationists, is revisited here because of its relevance to an assessment of undiscovered oil and gas potential in the Gulf Coast of Louisiana. The transition from normally pressured to highly overpressured sediments is documented by converting mud weights to pressure, plotting all pressure data from an individual field as a function of depth, and selecting a top and base of the pressure transition zone. Vertical extents of pressure transition zones in 34 fields across southern onshore Louisiana range from 300 to 9000 ft and are greatest in younger strata and in the larger fields. Display of pressure transition zones on geologic cross sections illustrates the relative independence of the depth of the pressure transition zone and geologic age. Comparison of the depth distribution of pressure transition zones with production intervals confirms previous findings that production intervals generally overlap the pressure transition zone in depth and that the median production depth lies above the base of the pressure transition zone in most fields. However, in 11 of 55 fields with deep drilling, substantial amounts of oil and gas have been produced from depths deeper than 2000 ft below the base of the pressure transition zone. Mud-weight data in 7 fields show that "local" pressure gradients range from 0.91 to 1.26 psi/ft below the base of the pressure transition zone. Pressure gradients are higher and computed effective stress gradients are negative in younger strata in coastal areas, indicating that a greater potential for fluid and sediment movement exists there than in older Tertiary strata.

  8. Blast induced neurotrauma causes overpressure dependent changes to the DNA methylation equilibrium.

    PubMed

    Bailey, Zachary S; Grinter, Michael B; De La Torre Campos, Diego; VandeVord, Pamela J

    2015-09-14

    Traumatic brain injury (TBI) has a high prevalence in our society and often leads to morbidity and mortality. TBI also occurs frequently in a military setting where exposure to blast waves is common. Abnormal gene expression involved with oxidative stress, inflammation and neuronal apoptosis has been well documented following blast induced neurotrauma (BINT). Altered epigenetic transcriptional regulation through DNA methylation has been implicated in the pathology of the injury. Imbalance between DNA methylation and DNA demethylation may lead to altered methylation patterns and subsequent changes in gene transcription. DNA methyltransferase enzymes (DNMT1, DNMT3a, and DNMT3b) are responsible for the addition of methyl groups to DNA, DNA methylation. Whereas the combined function of ten-eleven translocation enzymes (TET1, TET2, and TET3) and thymine-DNA glycosylase (TDG) result in the removal of methyl groups from DNA, DNA demethylation. We used an established rodent model of BINT to assess changes in DNA methylation and demethylation enzymes following injury. Three different blast overpressures were investigated (10, 17 and 23psi). Gene expression was investigated in the prefrontal cortex and hippocampus two weeks following injury. We observed DNMT, TET and TDG expression changes between pressure groups and brain regions. The hippocampus was more vulnerable to enzyme expression changes than the prefrontal cortex, which correlated with aberrant DNA methylation. A significant negative correlation was found between global DNA methylation and the magnitude of blast overpressure exposure. Through transcriptional regulation, altered DNA methylation patterns may offer insight into the characteristic outcomes associated with the injury pathology including inflammation, oxidative stress and apoptosis. As such, these enzymes may be important targets to future therapeutic intervention strategies. Published by Elsevier Ireland Ltd.

  9. Uncertainty quantification of overpressure buildup through inverse modeling of compaction processes in sedimentary basins

    NASA Astrophysics Data System (ADS)

    Colombo, Ivo; Porta, Giovanni M.; Ruffo, Paolo; Guadagnini, Alberto

    2016-11-01

    This study illustrates a procedure conducive to a preliminary risk analysis of overpressure development in sedimentary basins characterized by alternating depositional events of sandstone and shale layers. The approach rests on two key elements: (1) forward modeling of fluid flow and compaction, and (2) application of a model-complexity reduction technique based on a generalized polynomial chaos expansion (gPCE). The forward model considers a one-dimensional vertical compaction processes. The gPCE model is then used in an inverse modeling context to obtain efficient model parameter estimation and uncertainty quantification. The methodology is applied to two field settings considered in previous literature works, i.e. the Venture Field (Scotian Shelf, Canada) and the Navarin Basin (Bering Sea, Alaska, USA), relying on available porosity and pressure information for model calibration. It is found that the best result is obtained when porosity and pressure data are considered jointly in the model calibration procedure. Uncertainty propagation from unknown input parameters to model outputs, such as pore pressure vertical distribution, is investigated and quantified. This modeling strategy enables one to quantify the relative importance of key phenomena governing the feedback between sediment compaction and fluid flow processes and driving the buildup of fluid overpressure in stratified sedimentary basins characterized by the presence of low-permeability layers. The results here illustrated (1) allow for diagnosis of the critical role played by the parameters of quantitative formulations linking porosity and permeability in compacted shales and (2) provide an explicit and detailed quantification of the effects of their uncertainty in field settings.

  10. Uncertainty quantification of overpressure buildup through inverse modeling of compaction processes in sedimentary basins

    NASA Astrophysics Data System (ADS)

    Colombo, Ivo; Porta, Giovanni M.; Ruffo, Paolo; Guadagnini, Alberto

    2017-03-01

    This study illustrates a procedure conducive to a preliminary risk analysis of overpressure development in sedimentary basins characterized by alternating depositional events of sandstone and shale layers. The approach rests on two key elements: (1) forward modeling of fluid flow and compaction, and (2) application of a model-complexity reduction technique based on a generalized polynomial chaos expansion (gPCE). The forward model considers a one-dimensional vertical compaction processes. The gPCE model is then used in an inverse modeling context to obtain efficient model parameter estimation and uncertainty quantification. The methodology is applied to two field settings considered in previous literature works, i.e. the Venture Field (Scotian Shelf, Canada) and the Navarin Basin (Bering Sea, Alaska, USA), relying on available porosity and pressure information for model calibration. It is found that the best result is obtained when porosity and pressure data are considered jointly in the model calibration procedure. Uncertainty propagation from unknown input parameters to model outputs, such as pore pressure vertical distribution, is investigated and quantified. This modeling strategy enables one to quantify the relative importance of key phenomena governing the feedback between sediment compaction and fluid flow processes and driving the buildup of fluid overpressure in stratified sedimentary basins characterized by the presence of low-permeability layers. The results here illustrated (1) allow for diagnosis of the critical role played by the parameters of quantitative formulations linking porosity and permeability in compacted shales and (2) provide an explicit and detailed quantification of the effects of their uncertainty in field settings.

  11. The role of overpressure and seismic activity for the generation of the Tampen Slide, North Sea Trough Mouth Fan

    NASA Astrophysics Data System (ADS)

    Bellwald, Benjamin; Urlaub, Morelia; Oline Hjelstuen, Berit; Petter Sejrup, Hans; Sørensen, Mathilde; Forsberg, Carl Fredrik; Vanneste, Maarten

    2017-04-01

    Trough mouth fans (TMFs) are environments characterized by high sediment supply during glacial stages and repeated slope failure. The Tampen Slide, which removed 1800 km3 of sediment at 130 ka BP, is one of several paleo-slides at the North Sea TMF deposited at the outlet of the Norwegian Channel, SE Nordic Sea margin. Here we use 2D Finite Element Modeling to evaluate the effects of variations in sedimentation rates and sediment properties on overpressure generation and slope stability of this TMF system. The model domain, 40 km in length and 2 km in height, is dominated by deposits of glacigenic debris flows and glacimarine processes. We use geotechnical values measured on samples of glacial debris and (glaci)marine deposits from over the Ormen Lange gas field area. Slope stability has been modeled for constant temporal sediment loading, episodic changes in sedimentation rates and abrupt pulses in sediment delivery for the 61 ka of marine isotope stage 6. The models show that increased sedimentation rates during glacial stages generate insufficient overpressure to trigger the Tampen Slide. Furthermore, the simulated overpressures do not significantly differ at the end of the model runs characterized by different sedimentation patterns. The results also highlight the importance of a basal glacimarine layer underneath the rapidly-deposited sediments for the build-up of overpressure. Consequently, this glacimarine layer has the inherited potential to act as a weak layer facilitating instability. However, as overpressure due to sediment deposition alone does not result in slope failure, we couple the preconditioned slope with earthquake ground shaking. Based on attenuation models, an earthquake of M6.9 or larger at a short distance from the Tampen Slide headwall could have triggered the Tampen Slide. Therefore we suggest glacial sedimentation and a glacimarine layer to represent preconditioning factors, and seismic shaking as the controlling factor for the Tampen

  12. Vacuum system of the compact Energy Recovery Linac

    SciTech Connect

    Honda, T. Tanimoto, Y.; Nogami, T.; Takai, R.; Obina, T.; Asaoka, S.; Uchiyama, T.; Nakamura, N.

    2016-07-27

    The compact Energy Recovery Linac (cERL), a test accelerator to establish important technologies demanded for future ERL-based light sources, was constructed in late 2013 at KEK. The accelerator was successfully commissioned in early 2014, and demonstrated beam circulation with energy recovery. In the cERL vacuum system, low-impedance vacuum components are required to circulate high-intensity, low-emittance and short-bunch electron beams. We therefore developed ultra-high-vacuum (UHV)-compatible flanges that can connect beam tubes seamlessly, and employed retractable beam monitors, namely, a movable Faraday cup and screen monitors. In most parts of the accelerator, pressures below 1×10{sup −7} Pa are required to mitigate beam-gas interactions. Particularly, near the photocathode electron gun and the superconducting (SC) cavities, pressures below 1×10{sup −8} Pa are required. The beam tubes in the sections adjoining the SC cavities were coated with non-evaporable getter (NEG) materials, to reduce gas condensation on the cryo-surfaces. During the accelerator commissioning, stray magnetic fields from the permanent magnets of some cold cathode gauges (CCGs) were identified as a source of the disturbance to the beam orbit. Magnetic shielding was specially designed as a remedy for this issue.

  13. Beam director design report

    SciTech Connect

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  14. EFFECTS OF TRANSFERSE BEAM SIZE IN BEAM POSITIONS MONITORS

    SciTech Connect

    S.S. KURENNOY

    2001-06-01

    The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.

  15. Vacuum MOCVD fabrication of high efficience cells

    NASA Technical Reports Server (NTRS)

    Partain, L. D.; Fraas, L. M.; Mcleod, P. S.; Cape, J. A.

    1985-01-01

    Vacuum metal-organic-chemical-vapor-deposition (MOCVD) is a new fabrication process with improved safety and easier scalability due to its metal rather than glass construction and its uniform multiport gas injection system. It uses source materials more efficiently than other methods because the vacuum molecular flow conditions allow the high sticking coefficient reactants to reach the substrates as undeflected molecular beams and the hot chamber walls cause the low sticking coefficient reactants to bounce off the walls and interact with the substrates many times. This high source utilization reduces the materials costs power device and substantially decreases the amounts of toxic materials that must be handled as process effluents. The molecular beams allow precise growth control. With improved source purifications, vacuum MOCVD has provided p GaAs layers with 10-micron minority carrier diffusion lengths and GaAs and GaAsSb solar cells with 20% AMO efficiencies at 59X and 99X sunlight concentration ratios. Mechanical stacking has been identified as the quickest, most direct and logical path to stacked multiple-junction solar cells that perform better than the best single-junction devices. The mechanical stack is configured for immediate use in solar arrays and allows interconnections that improve the system end-of-life performance in space.

  16. 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.

  17. Beam splitter for squeezed light

    NASA Astrophysics Data System (ADS)

    Qu, Weizhi; Sun, Jian; Mikhailov, Eugeniy; Novikova, Irina; Shen, Heng; Xiao, Yanhong

    2016-05-01

    A conventional beam splitter can split classical light beams, but when used for squeezed light, the non-classical property is often lost at the beam splitter output. Here, we demonstrate a beam splitter made of moving atoms that can split squeezed light. Squeezed vacuum is generated by a degenerate four-wave-mixing (FWM) process in one location (Ch1) of a wall-coated Rb vapor cell, and then due to coherent diffusion of ground state coherence of the atoms within the cell, squeezed vacuum can be generated in a different location (Ch2) of the cell where no squeezing would exist without the presence of the Ch1, because of a relatively weak laser input. We attribute the phenomenon to FWM enhanced by coherence transfer. This effectively forms a beam splitter for squeezed light. We built a simple model that produces results in qualitative agreement with our experimental observations.

  18. Superoleophobicity under vacuum

    NASA Astrophysics Data System (ADS)

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Bell, Steven E. J.; Liu, Weimin; Zhou, Feng

    2011-05-01

    By using superoleophobic alumina and low vapor pressure oils we have been able to study wetting behavior at high vacuum. Here, we show that a superoleophobic state can exist for some probe liquids, even under high vacuum. However, with other liquids the surfaces are only superoloephobic because air is trapped beneath the droplet and the contact angle decreases dramatically (150°-120°) if this air is removed. These observations open up the possibility of designing materials which fully exploit the potential of physically trapped air to achieve extreme oleophobicity and/or hydrophobicity.

  19. Redesigned Electron-Beam Furnace Boosts Productivity

    NASA Technical Reports Server (NTRS)

    Williams, Gary A.

    1995-01-01

    Redesigned electron-beam furnace features carousel of greater capacity so more experiments conducted per loading, and time spent on reloading and vacuum pump-down reduced. Common mounting plate for electron source and carousel simplifies installation and reduces vibration.

  20. Redesigned Electron-Beam Furnace Boosts Productivity

    NASA Technical Reports Server (NTRS)

    Williams, Gary A.

    1995-01-01

    Redesigned electron-beam furnace features carousel of greater capacity so more experiments conducted per loading, and time spent on reloading and vacuum pump-down reduced. Common mounting plate for electron source and carousel simplifies installation and reduces vibration.

  1. Technical Seminar: Electron Beam Forming Fabrication

    NASA Image and Video Library

    EBF³ uses a focused electron beam in a vacuum environment to create a molten pool on a metallic substrate. This layer-additive process enables fabrication of parts directly from CAD drawings. The ...

  2. TMX-Upgrade vacuum-system design and analysis

    SciTech Connect

    Simonen, T.C.; Chargin, A.K.; Drake, R.P.; Nexsen, W.E.; Pickles, W.L.; Poulsen, P.; Stack, T.P.; Wong, R.L.

    1981-10-01

    This paper describes the design and analysis of the TMX Upgrade Vacuum System. TMX Upgrade is a modification of the TMX tandem mirror device. It will employ thermal barriers to further improve plasma confinement. Thermal barriers are produced by microwave heating and neutral-beam pumping. They increase the feasibility of tandem-mirror reactors by reducing both the required magnetic field strengths and the neutral-beam injection voltages.

  3. 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.

  4. A beam scraper using a linear motor

    SciTech Connect

    Beadle, E.R.; Rodger, E.S.; Thern, R.E.

    1989-01-01

    A beam scraper using a linear motor drive has been developed for use in the AGS at Brookhaven National Laboratory. The device is used to measure beam size by moving a target to a predetermined location and measuring the intercepted beam with nearby loss monitors or by noting the decrease in the circulating beam current. This device has excellent vacuum characteristics, as the motor and sensor coils are outside the vacuum, coupled magnetically to the moving parts which are inside. There are no bellows or dynamic seals required. The position-time profile is controlled by a closed-loop servo system which uses position feedback. 2 refs., 4 figs.

  5. VACUUM SEALING MEANS FOR LOW VACUUM PRESSURES

    DOEpatents

    Milleron, N.

    1962-06-12

    S>A vacuum seal is designed in which the surface tension of a thin layer of liquid metal of low vapor pressure cooperates with adjacent surfaces to preclude passages of gases across pressure differentials as low as 10/sup -8/ mm Hg. Mating contiguous surfaces composed of copper, brass, stainless steel, nickel, molybdenum, tungsten, tantalum, glass, quartz, and/or synthetic mica are disposed to provide a maximum tolerance, D, expressed by 2 gamma /P/sub 1/, where gamma is the coefflcient of the surface tension of the metal sealant selected in dynes/cm/sub 2/. Means for heating the surfaces remotely is provided where temperatures drop below about 250 deg C. A sealant consisting of an alloy of gallium, indium, and tin, among other combinations tabulated, is disposed therebetween after treating the surfaces to improve wettability, as by ultrasonic vibrations, the surfaces and sealants being selected according to the anticipated experimental conditions of use. (AEC)

  6. Small Vacuum Compatible Hyperthermal Atom Generator

    NASA Technical Reports Server (NTRS)

    Outlaw, Ronald A. (Inventor); Davidson, Mark R. (Inventor)

    1998-01-01

    A vacuum compatible hyperthermal atom generator includes a membrane having two sides. the membrane having the capability of dissolving atoms into the membrane's bulk. A first housing is furnished in operative association with the first side of the membrane to provide for the exposure of the first side of the membrane to a gas species. A second housing is furnished in operative association with the second side of the membrane to provide a vacuum environment having a pressure of less than 1 x 10(exp -3) Torr on the second side of the membrane. Exciting means excites atoms adsorbed on the second side of the membrane to a non-binding state so that a portion from 0% to 100% of atoms adsorbed on the second side of is the membrane are released from the second side of the membrane primarily as an atom beam.

  7. Tailored vacuum chambers for ac magnets

    SciTech Connect

    Harvey, A.

    1985-01-01

    The proposed LAMPF-II accelerator has a 60-Hz booster synchrotron and a 3-Hz main ring. To provide a vacuum enclosure inside the magnets with low eddy-current losses and minimal field distortion, yet capable of carrying rf image currents and providing beam stabilization, we propose an innovative combination pipe. Structurally, the enclosure is high-purity alumina ceramic, which is strong, radiation resistant, and has good vacuum properties. Applied to the chamber are thin, spaced, silver conductors using adapted thick-film technology. The conductor design can be tailored to the stabilization requirements, for example, longitudinal conductors for image currents, circumferential for transverse stabilization. The inside of the chamber has a thin, resistive coating to avoid charge build-up. The overall 60-Hz power loss is less than 100 W/m.

  8. Vacuum Kundt waves

    NASA Astrophysics Data System (ADS)

    McNutt, David; Milson, Robert; Coley, Alan

    2013-03-01

    We discuss the invariant classification of vacuum Kundt waves using the Cartan-Karlhede algorithm and determine the upper bound on the number of iterations of the Karlhede algorithm to classify the vacuum Kundt waves (Collins (1991 Class. Quantum Grav. 8 1859-69), Machado Ramos (1996 Class. Quantum Grav. 13 1589)). By choosing a particular coordinate system we partially construct the canonical coframe used in the classification to study the functional dependence of the invariants arising at each iteration of the algorithm. We provide a new upper bound, q ⩽ 4, and show that this bound is sharp by analyzing the subclass of Kundt waves with invariant count beginning with (0, 1,…) to show that the class with invariant count (0, 1, 3, 4, 4) exists. This class of vacuum Kundt waves is shown to be unique as the only set of metrics requiring the fourth covariant derivatives of the curvature. We conclude with an invariant classification of the vacuum Kundt waves using a suite of invariants.

  9. Sorption vacuum trap

    NASA Technical Reports Server (NTRS)

    Barrington, A. E.; Caruso, A. J.

    1970-01-01

    Modified sorption trap for use in high vacuum systems contains provisions for online regeneration of sorbent material. Trap is so constructed that it has a number of encapsulated resistance heaters and a valving and pumping device for removing gases from heated sorbing material. Excessive downtime is eliminated with this trap.

  10. Various unique vacuum holders

    SciTech Connect

    Gregar, J.S.

    1992-12-01

    Glassblowers use vacuum holding devices to support a flat plate in the glassflowing lathe to seal onto the end of, or inside of, a glass cylinder. Glassblowing blowhose swivels tend to leak; a rotating union from the hydraulics industry is better. Various graphite holder designs are described.

  11. Vacuum ultraviolet holography

    NASA Technical Reports Server (NTRS)

    Bjorklund, G. C.; Harris, S. E.; Young, J. F.

    1974-01-01

    The authors report the first demonstration of holographic techniques in the vacuum ultraviolet spectral region. Holograms were produced with coherent 1182 A radiation. The holograms were recorded in polymethyl methacrylate and read out with an electron microscope. A holographic grating with a fringe spacing of 836 A was produced and far-field Fraunhofer holograms of sub-micron particles were recorded.

  12. Gas injected vacuum switch

    DOEpatents

    Hardin, K. Dan

    1977-01-01

    The disclosure relates to a gas injected vacuum switch comprising a housing having an interior chamber, a conduit for evacuating the interior chamber, within the chamber an anode and a cathode spaced from the anode, and a detonator for injecting electrically conductive gas into the chamber between the anode and the cathode to provide a current path therebetween.

  13. Titanium alloy as a potential low radioactivation vacuum material

    SciTech Connect

    Kamiya, Junichiro Hikichi, Yusuke; Kinsho, Michikazu; Ogiwara, Norio; Fukuda, Mitsuhiro; Hamatani, Noriaki; Hatanaka, Kichiji; Kamakura, Keita; Takahisa, Keiji

    2015-05-15

    For the vacuum systems of high-intensity beam accelerators, low radioactivation materials with good vacuum characteristics and high mechanical strength are required. The titanium alloy Ti-6Al-4V was investigated as a potential low activation vacuum material with high mechanical strength for the fabrication of vacuum components, particularly the flanges of beam pipes, in the J-PARC 3 GeV synchrotron. The dose rate of Ti-6Al-4V when irradiated by a 400 MeV proton was observed to decrease more rapidly than that of stainless steel. Furthermore, the generated radioactive isotopes were nuclides with relatively short half-lives. The outgassing rate per unit area of Ti-6Al-4V was approximately 10{sup −8 }Pa m{sup 3}/s m{sup 2} after pumping for 100 h, which is the same as the typical value for stainless steel. Additionally, the hydrogen concentration in bulk Ti-6Al-4V was reduced to approximately 1 ppm by vacuum firing at 700 °C for 9 h; the mechanical strength was not reduced by this process. These results indicate that Ti-6Al-4V is a good candidate for use as a low activation vacuum material with high mechanical strength.

  14. New beam instrumentation in the AGS Booster

    SciTech Connect

    Witkover, R.L.

    1991-01-01

    The AGS Booster was designed to accelerate beams from 2{times}10{sup 10} polarized protons to 1.5{times}10{sup 13} protons and heavy ions through Au{sup +33}. The range of beam parameters and the high vacuum, and radiation environment presented challenges for the beam instrumentation. Some interesting beam monitors in the Booster and transport lines, will be described. Where available, results will be presented. 21 refs., 7 figs.

  15. APPARATUS FOR VACUUM DEPOSITION OF METALS

    DOEpatents

    Milleron, N.

    1962-03-13

    An apparatus and a method are described for continuous vacuum deposition of metals for metallic coatings, for ultra-high vacuum work, for purification of metals, for maintaining high-density electron currents, and for other uses. The apparatus comprises an externally cooled feeder tube extending into a container and adapted to feed metal wire or strip so that it emerges in a generally vertical position therein. The tube also provides shielding from the heat produced by an electron beam therein focused to impinge from a vertical direction upon the tip of the emerging wire. By proper control of the wire feed, coolant feed, and electron beam intensity, a molten ball of metal forms upon the emerging tip and remains self-supported thereon by the interaction of various forces. The metal is vaporized and travels in a line of sight direction, while additional wire is fed from the tube, so that the size of the molten ball remains constant. In the preferred embodiments, the wire is selected from a number of gettering metals and is degassed by electrical resistance in an adjacent chamber which is also partially evacuated. The wire is then fed through the feed tube into the electron beam and vaporizes and adsorbs gases to provide pumping action while being continuously deposited upon surfaces within the chamber. Ion pump electrodes may also be provided within line of sight of the vaporizing metal source to enhance the pumping action. (AEC)

  16. 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…

  17. 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…

  18. Switches in the Stress Field Induced by Fluid Overpressures Below a Low-Permeability Fault Zone

    NASA Astrophysics Data System (ADS)

    Collettini, C.; de Paola, N.; Goulty, N. R.

    2005-12-01

    The geological structure of Elba comprises thrust sheets stacked during the Apennine orogeny that are cross-cut by later Neogene extensional faults. The Zuccale fault is a gently east-dipping normal fault that offsets part of the thrust stack eastwards. Stratigraphic separations imply an offset of 7-8 km and exhumation of 3-6 km. A complex hydrofracture system exposed in the footwall of Palaeozoic schists and Triassic sediments at Punta di Zuccale consists of three vein sets: two vertical sets trending N-S and E-W and one sub-horizontal. The veins show a crack-and-seal texture and are characterized by mutual crosscutting relationships. The regional stress field throughout the period when the Zuccale fault was active, evidenced by numerous kinematic indicators, was extensional with the minimum principal stress oriented E-W, consistent with the N-S trending set of vertical hydrofractures. We interpret the vertical E-W trending and sub-horizontal hydrofractures as the result of overpressure development, due to exhumation, below the low-permeability, phyllosilicate-rich fault core. In our proposed mechanical model, exhumation reduced the vertical stress and also the horizontal stresses which responded poroelastically. The N-S trending vertical hydrofractures formed when the pore pressure exceeded the minimum principal stress by the tensile strength of the rock. Continued exhumation further reduced the vertical and N-S principal stresses, whilst the E-W principal stress remained equal to the pore pressure, until the pore pressure exceeded the N-S principal stress by the tensile strength of the rock, causing the E-W hydrofractures to form. Yet more exhumation further reduced the vertical stress, while the horizontal stresses remained equal to the pore pressure, until the pore pressure exceeded the vertical stress by the tensile strength of the rock, causing the sub-horizontal hydrofractures to form. The reduced normal effective stress across the fault encouraged fault

  19. Prevention of Over-Pressurization During Combustion in a Sealed Chamber

    NASA Technical Reports Server (NTRS)

    Gokoglu, Suleyman A.; Niehaus, Justin E.; Olson, Sandra L.; Dietrich, Daniel L.; Ruff, Gary A.; Johnston, Michael C.

    2012-01-01

    The combustion of flammable material in a sealed chamber invariably leads to an initial pressure rise in the volume. The pressure rise is due to the increase in the total number of gaseous moles (condensed fuel plus chamber oxygen combining to form gaseous carbon dioxide and water vapor) and, most importantly, the temperature rise of the gas in the chamber. Though the rise in temperature and pressure would reduce with time after flame extinguishment due to the absorption of heat by the walls and contents of the sealed spacecraft, the initial pressure rise from a fire, if large enough, could lead to a vehicle over-pressure and the release of gas through the pressure relief valve. This paper presents a simple lumped-parameter model of the pressure rise in a sealed chamber resulting from the heat release during combustion. The transient model considers the increase in gaseous moles due to combustion, and heat transfer to the chamber walls by convection and radiation and to the fuel-sample holder by conduction, as a function of the burning rate of the material. The results of the model are compared to the pressure rise in an experimental chamber during flame spread tests as well as to the pressure falloff after flame extinguishment. The experiments involve flame spread over thin solid fuel samples. Estimates of the heat release rate profiles for input to the model come from the assumed stoichiometric burning of the fuel along with the observed flame spread behavior. The sensitivity of the model to predict maximum chamber pressure is determined with respect to the uncertainties in input parameters. Model predictions are also presented for the pressure profile anticipated in the Fire Safety-1 experiment, a material flammability and fire safety experiment proposed for the European Space Agency (ESA) Automated Transfer Vehicle (ATV). Computations are done for a range of scenarios including various initial pressures and sample sizes. Based on these results, various

  20. Attenuation of pulmonary inflammation after exposure to blast overpressure by N-acetylcysteine amide.

    PubMed

    Chavko, Mikulas; Adeeb, Saleena; Ahlers, Stephen T; McCarron, Richard M

    2009-09-01

    Lung contusion is a common problem from blunt chest trauma caused by mechanical forces and by exposure to blast overpressure, often with fatal consequences. Lung contusion is also a risk factor for the development of pneumonia, severe clinical acute lung injury (ALI), and acute respiratory distress syndrome (ARDS). Infiltrating neutrophils are considered to be central mediators of lung injuries after blunt trauma. Recent studies have demonstrated that antioxidants reduced pulmonary inflammation in different models of lung damage. This study examined the effect of antioxidant N-acetylcysteine amide (NACA) on the progression of lung inflammation after exposure to a moderate level of blast overpressure (140 kPa). Rats were administered with NACA (i.p. 100 mg/kg) or placebo (PBS) 30, 60 min and 24 h after exposure. Nonblasted sham-injected animals served as controls. Neutrophil infiltration measured by myeloperoxidase (MPO) activity in the lung was significantly increased at 2 days after blast and returned to controls at 8 days. This increase corresponded with activation of integrin CD11b mRNA and lung inflammatory chemokine mRNA expression; macrophage inflammatory protein-1 (MIP-1), monocyte chemotactic peptide-1 (MCP-1), and cytokine-induced neutrophil chemoattractant-1 (CINC-1). At 8 days, all inflammatory mediators returned to control levels. In addition, expression of heme oxygenase-1 (HO-1) mRNA increased at 2 days after exposure. No changes were detected in the lung manganase superoxide dismutase (MnSOD) or glutathione reductase (GR) mRNA expression after blast. N-Acetylcysteine amide significantly reduced infiltration of neutrophils and CD11b mRNA activation in lungs, and completely blocked activation of MIP-1, MCP-1 and CINC-1 mRNA. The relatively higher inhibition of chemokine mRNAs compared with reduction in MPO activity and CD11b is in accordance with an antioxidant effect of NACA on reactive oxygen species (ROS) accumulation, rather than by an effect on

  1. The significance of vortex ring formation and nozzle exit over-pressure to pulsatile jet propulsion

    NASA Astrophysics Data System (ADS)

    Krueger, Paul Samuel

    Pulsatile jet propulsion can be accomplished using a fully-pulsed jet (i.e., a periodic series of starting jets or pulses), the unsteady nature of which engenders vortex ring formation. The propulsive significance of vortex ring formation in this setting is studied experimentally using a piston-cylinder mechanism to generate starting and fully-pulsed, round jets of water into water. Starting jets are considered separately since they are the limiting case of a fully-pulsed jet at zero pulsing frequency. Measurements of the total impulse per pulse (starting jets) and time-averaged thrust (fully-pulsed jets) are made using a force balance. Digital particle image velocimetry (DPIV) measurements provide information about the resulting jet flow. Piston stroke to diameter ratios (L/D) between 2 and 8 are used to generate the pulses for both types of jets. This range brackets the transition between pulses that generate isolated vortex rings (small L/D) and pulses that yield a leading vortex ring that has pinched off from the generating jet, producing a trailing jet (large L/D). Impulse measurements for the starting jets as a function of L/D indicate the leading vortex ring adds proportionately more impulse per pulse than a trailing jet. This leads to a maximum in the average thrust during a pulse at an L/D just before vortex ring pinch off is observed. The propulsive advantage of vortex ring formation over trailing-jet ejection is due to nozzle exit over-pressure. This over-pressure can be related to the acceleration of ambient fluid in the form of added and entrained mass during ring formation. A simple model is proposed to describe these effects at the initiation of an impulsive pulse. The thrust measurements for fully-pulsed jets show a propulsive benefit from vortex ring formation (i.e., non-dimensional thrust, FIJ , > 1) for all non-dimensional pulsing frequencies, StL, accessible by a fully-pulsed jet. As with starting jets (StL = 0), vortex ring pinch off reduces

  2. Modelling shear bands in a volcanic conduit: Implications for over-pressures and extrusion-rates

    NASA Astrophysics Data System (ADS)

    Hale, Alina J.; Mühlhaus, Hans-B.

    2007-11-01

    Shear bands in a volcanic conduit are modelled for crystal-rich magma flow using simplified conditions to capture the fundamental behaviour of a natural system. Our simulations begin with magma crystallinity in equilibrium with an applied pressure field and isothermal conditions. The viscosity of the magma is derived using existing empirical equations and is dependent upon temperature, water content and crystallinity. From these initial conduit conditions we utilize the Finite Element Method, using axi-symmetric coordinates, to simulate shear bands via shear localisation. We use the von Mises visco-plasticity model with constant magma shear strength for a first look into the effects of plasticity. The extent of shear bands in the conduit is explored with a numerical model parameterized with values appropriate for Soufrière Hills Volcano, Montserrat, although the model is generic in nature. Our model simulates shallow (up to approximately 700 m) shear bands that occur within the upper conduit and probably govern the lava extrusion style due to shear boundaries. We also model the change in the over-pressure field within the conduit for flow with and without shear bands. The pressure change can be as large as several MPa at shallow depths in the conduit, which generates a maximum change in the pressure gradient of 10's of kPa/m. The formation of shear bands could therefore provide an alternative or additional mechanism for the inflation/deflation of the volcano flanks as measured by tilt-metres. Shear bands are found to have a significant effect upon the magma ascent rate due to shear-induced flow reducing conduit friction and altering the over-pressure in the upper conduit. Since we do not model frictional controlled slip, only plastic flow, our model calculates the minimum change in extrusion rate due to shear bands. However, extrusion rates can almost double due to the formation of shear bands, which may help suppress volatile loss. Due to the paucity of data and

  3. Practical beam transport for PFI

    NASA Astrophysics Data System (ADS)

    Mozurkewich, David; Young, John; Ireland, Michael

    2016-08-01

    The Planet Formation Imager (PFI) is a future kilometric-baseline infrared interferometer to image the complex physical processes of planet formation. Technologies that could be used to transport starlight to a central beam-combining laboratory in PFI include free-space propagation in air or vacuum, and optical fibres. This paper addresses the design and cost issues associated with free-space propagation in vacuum pipes. The signal losses due to diffraction over long differential paths are evaluated, and conceptual beam transport designs employing pupil management to ameliorate these losses are presented and discussed.

  4. Furnace brazing under partial vacuum

    NASA Technical Reports Server (NTRS)

    Mckown, R. D.

    1979-01-01

    Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

  5. Gas bearing operates in vacuum

    NASA Technical Reports Server (NTRS)

    Perkins, G. S.

    1975-01-01

    Bearing has restrictions to reduce air leaks and is connected to external pumpout facility which removes exhausted air. Token amount of air which is lost to vacuum is easily removed by conventional vacuum pump.

  6. Tritium handling in vacuum systems

    SciTech Connect

    Gill, J.T.; Coffin, D.O.

    1986-10-01

    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  7. Furnace brazing under partial vacuum

    NASA Technical Reports Server (NTRS)

    Mckown, R. D.

    1979-01-01

    Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

  8. A new vacuum component: fast acting puncture valve

    NASA Astrophysics Data System (ADS)

    Mallick, B.

    2008-05-01

    Generally, for proton induced X-ray emission (PIXE), external-PIXE, gamma ray spectrometry, charge particle spectrometry or ion beam irradiation in air using large vacuum system like particle accelerator, a thin Mylar or Kapton foil are used as a window material (chamber) for above beams to perform experiments. The problem arises when this thin Mylar or Kapton foil gets destroyed accidentally in mid-run. Air with high velocity rushes inside, which disturbs the inside vacuum of the chamber or beam lines and causes failure of the experimental system. In order to avoid this, one needs a sensitive arrangement, which can sense the rush of air and stop it entering in to the vacuum chamber or lines. The solution to the above problem is achieved by design a new fast acting puncture valve. The valve is working on the basis of differential pressure and the basic underlying principle to sense the rushing air is based on Bernoulli's principle and Pascal's law, which is different from commercially available fast acting valve. The new valve is installed in the External beam line of 3MV tandem pelletron accelerator at Institute of Physics, Bhubaneswar and working fine in both rough as well as high vacuum.

  9. 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.

  10. First commissioning of the SuperKEKB vacuum system

    NASA Astrophysics Data System (ADS)

    Suetsugu, Y.; Shibata, K.; Ishibashi, T.; Kanazawa, K.; Shirai, M.; Terui, S.; Hisamatsu, H.

    2016-12-01

    The first (Phase-1) commissioning of SuperKEKB, an asymmetric-energy electron-positron collider at KEK, began in February 2016, after more than five years of upgradation work on KEKB and successfully ended in June 2016. A major task of the Phase-1 commissioning was the vacuum scrubbing of new beam pipes in anticipation of a sufficiently long beam lifetime and low background noise in the next commissioning, prior to which a new particle detector will be installed. The pressure rise per unit beam current decreased steadily with increasing beam dose, as expected. Another important task was to check the stabilities of various new vacuum components at high beam currents of approximately 1 A. The temperature increases of the bellows chambers, gate valves, connection flanges, and so on were less than several degrees at 1 A, and no serious problems were found. The effectiveness of the antechambers and TiN coating in suppressing the electron-cloud effect (ECE) in the positron ring was also confirmed. However, the ECE in the Al-alloy bellows chambers was observed where TiN had not been coated. The use of permanent magnets to create an axial magnetic field of approximately 100 G successfully suppressed this effect. Pressure bursts accompanying beam losses were also frequently observed in the positron ring. This phenomenon is still under investigation, but it is likely caused by collisions between the circulating beams and dust particles, especially in the dipole magnet beam pipes.

  11. Testing of vacuum pumps for APT/LEDA RFQ

    SciTech Connect

    Behne, D; Shen, S; Valdiviez, R; Wilson, N G: Schrage, D

    1998-08-06

    Two vacuum systems were designed and built for the RFQ (Radio Frequency Quadrupole) cavity in the APT/LEDA (Low Energy Demonstration Accelerator) linac. The gas load from the proton beam required very high hydrogen pump speed and capacity. The gas load from the high power RF windows also required very high hydrogen pump speed for the RF window vacuum system. Cryopumps were chosen for the RFQ vacuum system and ST185 sintered non- evaporable getter (NEG) cartridges were chosen for the RF window vacuum system. Hydrogen pump speed and capacity measurements were carried out for a commercial cryopump and a NEG pump. This paper will discuss the test procedures and the results of the measurements.

  12. New-construction techniques and HVAC (heating, venting and air conditioning) overpressurization for radon reduction in schools

    SciTech Connect

    Witter, K.A.; Craig, A.B.; Saum, D.

    1988-04-01

    Construction of a school in Fairfax County, Virginia, is being carefully monitored since elevated indoor radon levels have been identified in many existing houses near the site. Soil-gas radon concentrations measured prior to pouring of the slabs were also indicative of a potential radon problem should the soil gas enter the school; however, subslab radon measurements collected thus far are lower than anticipated. In addition, the school's heating, ventilating, and air-conditioning (HVAC) system has been designed to operate continously in overpressurization to help reduce pressure-driven entry of radon-containing soil gas into the building. Following completion, indoor radon levels in the school will be monitored to determine the effectiveness of these radon-resistant new-construction techniques and HVAC overpressurization in limiting radon entry into the school.

  13. 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.

  14. Surge-damping vacuum valve

    DOEpatents

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  15. Portable vacuum object handling device

    DOEpatents

    Anderson, Gordon H.

    1983-08-09

    The disclosure relates to a portable device adapted to handle objects which are not to be touched by hand. A piston and bore wall form a vacuum chamber communicating with an adaptor sealably engageable with an object to be lifted. The piston is manually moved and set to establish vacuum. A valve is manually actuatable to apply the vacuum to lift the object.

  16. 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.

  17. Ultra-high vacuum photoelectron linear accelerator

    DOEpatents

    Yu, David U.L.; Luo, Yan

    2013-07-16

    An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

  18. Overpressure generation by load transfer following shale framework weakening due to smectite diagenesis

    USGS Publications Warehouse

    Lahann, R.W.; Swarbrick, R.E.

    2011-01-01

    Basin model studies which have addressed the importance of smectite conversion to illite as a source of overpressure in the Gulf of Mexico have principally relied on a single-shale compaction model and treated the smectite reaction as only a fluid-source term. Recent fluid pressure interpretation and shale petrology studies indicate that conversion of bound water to mobile water, dissolution of load-bearing grains, and increased preferred orientation change the compaction properties of the shale. This results in substantial changes in effective stress and fluid pressure. The resulting fluid pressure can be 1500-3000psi higher than pressures interpreted from models based on shallow compaction trends. Shale diagenesis changes the mineralogy, volume, and orientation of the load-bearing grains in the shale as well as the volume of bound water. This process creates a weaker (more compactable) grain framework. When these changes occur without fluid export from the shale, some of the stress is transferred from the grains onto the fluid. Observed relationships between shale density and calculated effective stress in Gulf of Mexico shelf wells confirm these changes in shale properties with depth. Further, the density-effective stress changes cannot be explained by fluid-expansion or fluid-source processes or by prediagenesis compaction, but are consistent with a dynamic diagenetic modification of the shale mineralogy, texture, and compaction properties during burial. These findings support the incorporation of diagenetic modification of compaction properties as part of the fluid pressure interpretation process. ?? 2011 Blackwell Publishing Ltd.

  19. Delineating Area of Review in a System with Pre-injection Relative Overpressure

    SciTech Connect

    Oldenburg, Curtis M.; Cihan, Abdullah; Zhou, Quanlin; Fairweather, Stacey; Spangler, Lee H.

    2014-12-31

    The Class VI permit application for geologic carbon sequestration (GCS) requires delineation of an area of review (AoR), defined as the region surrounding the (GCS) project where underground sources of drinking water (USDWs) may be endangered. The methods for estimating AoR under the Class VI regulation were developed assuming that GCS reservoirs would be in hydrostatic equilibrium with overlying aquifers. Here we develop and apply an approach to estimating AoR for sites with preinjection relative overpressure for which standard AoR estimation methods produces an infinite AoR. The approach we take is to compare brine leakage through a hypothetical open flow path in the base-case scenario (no-injection) to the incrementally larger leakage that would occur in the CO2-injection case. To estimate AoR by this method, we used semi-analytical solutions to single-phase flow equations to model reservoir pressurization and flow up (single) leaky wells located at progressively greater distances from the injection well. We found that the incrementally larger flow rates for hypothetical leaky wells located 6 km and 4 km from the injection well are ~20% and 30% greater, respectively, than hypothetical baseline leakage rates. If total brine leakage is considered, the results depend strongly on how the incremental increase in total leakage is calculated, varying from a few percent to up to 40% greater (at most at early time) than base-case total leakage.

  20. Experiments on Dynamic Overpressure Stabilization of Ablative Richtmyer--Meshkov Growth in ICF Targets on OMEGA

    NASA Astrophysics Data System (ADS)

    Gotchev, O. V.; Goncharov, V. N.; Jaanimagi, P. A.; Knauer, J. P.; Meyerhofer, D. D.

    2002-11-01

    Dynamic overpressure sets the growth rate of the ablative Richtmyer--Meshkov (RM) instability and the late-time imprint levels in directly driven ICF targets. It leads to temporal oscillations of the perturbed ablation front, which have been predicted analytically and observed experimentally,(Y. Aglitskiy et al.), Phys. Plasmas 9, 2264 (2002). and in 2-D ORCHID simulations. These predictions were verified on OMEGA by measuring the perturbation amplitudes and frequencies directly with an x-ray framing camera through face-on x-ray radiography. Planar plastic targets with variable thickness (20 to 60 μm) and single-mode (λ = 10 to 30 μm) ripples on the front surface were irradiated with 1.5-ns square UV laser pulses at maximum energy. Results clearly indicate a phase reversal in the evolution of the target areal density perturbations, in good agreement with theory and simulation. Nonlinearity in the evolution of the preimposed mode, resulting in an enriched spectrum, was observed for initial amplitudes previously believed to develop linearly with time. Upcoming experiments with a high-resolution, streaked imager, will allow for the detailed recording of the evolution of the RM instability and the competing stabilization effect. This work was supported by the U.S. DOE Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460.

  1. Results of Overpressurization Test of a 1:4-Scale Prestressed Concrete Containment Vessel Model

    SciTech Connect

    Hessheimer, Michael F.; Shibata, Satoru; Costello, James F.

    2002-07-01

    The Nuclear Power Engineering Corporation (NUPEC) of Japan and the U.S. Nuclear Regulatory Commission (NRC) have been co-sponsoring and jointly funding a Cooperative Containment Research Program at Sandia National Laboratories. The purpose of the program is to investigate the response of representative models of nuclear containment structures to pressure loading beyond the design basis accident and to compare analytical predictions with measured behavior. This is accomplished by conducting static, pneumatic overpressurization tests of scale models at ambient temperature. The first project in this program was a test of a mixed scale steel containment vessel (SCV). Next, a 1:4-scale model of a prestressed concrete containment vessel (PCCV), representative of a pressurized water reactor (PWR) plant in Japan, was constructed by NUPEC at Sandia National Laboratories from January 1997 through June, 2000. Concurrently, Sandia instrumented the model with over 1500 transducers to measure strain, displacement and forces in the model from prestressing through the pressure testing. The limit state test of the PCCV model was conducted in September, 2000 at Sandia National Laboratories. This paper describes the conduct and some of the results of this test. (authors)

  2. Petroleum and aqueous inclusions from deeply buried reservoirs: Experimental simulations and consequences for overpressure estimates

    NASA Astrophysics Data System (ADS)

    Pironon, Jacques; Bourdet, Julien

    2008-10-01

    Synthetic hydrocarbon and aqueous inclusions have been created in the laboratory batch reactors in order to mimic inclusion formation or re-equilibration in deeply buried reservoirs. Inclusions were synthesized in quartz and calcite using pure water and Mexican dead oil, or n-tetradecane (C 14H 30), at a temperature and pressure of 150 °C and 1 kbar. One-phase hydrocarbon inclusions are frequently observed at standard laboratory conditions leading to homogenization temperatures between 0 and 60 °C. UV epifluorescence of Mexican oil inclusions is not uniform; blue and green-yellow colored inclusions coexist; however, no clear evidence of variations in fluid chemistry were observed. Homogenization temperatures were recorded and the maxima of Th plotted on histograms are in good agreement with expected Th in a range of 6 °C. Broad histograms were reconstructed showing non-symmetrical Th distributions over a 20 °C temperature range centered on the expected Th. This histogram broadening is due to the fragility of the fluid inclusions that were created by re-filling of pre-existing microcavities. Such Th histograms are similar to Th histograms recorded on natural samples from deeply buried carbonate reservoirs. Th values lower than those expected were measured for hydrocarbon inclusions in quartz and calcite, and for aqueous inclusions in calcite. However, the results confirm the ability of fluid inclusions containing two immiscible fluids to lead to PT reconstructions, even in overpressured environments.

  3. Impact of reduced near-field entrainment of overpressured volcanic jets on plume development

    USGS Publications Warehouse

    Saffaraval, Farhad; Solovitz, Stephen A.; Ogden, Darcy E.; Mastin, Larry G.

    2012-01-01

    Volcanic plumes are often studied using one-dimensional analytical models, which use an empirical entrainment ratio to close the equations. Although this ratio is typically treated as constant, its value near the vent is significantly reduced due to flow development and overpressured conditions. To improve the accuracy of these models, a series of experiments was performed using particle image velocimetry, a high-accuracy, full-field velocity measurement technique. Experiments considered a high-speed jet with Reynolds numbers up to 467,000 and exit pressures up to 2.93 times atmospheric. Exit gas densities were also varied from 0.18 to 1.4 times that of air. The measured velocity was integrated to determine entrainment directly. For jets with exit pressures near atmospheric, entrainment was approximately 30% less than the fully developed level at 20 diameters from the exit. At pressures nearly three times that of the atmosphere, entrainment was 60% less. These results were introduced into Plumeria, a one-dimensional plume model, to examine the impact of reduced entrainment. The maximum column height was only slightly modified, but the critical radius for collapse was significantly reduced, decreasing by nearly a factor of two at moderate eruptive pressures.

  4. Blast overpressure induced axonal injury changes in rat brainstem and spinal cord.

    PubMed

    Kallakuri, Srinivasu; Purkait, Heena S; Dalavayi, Satya; VandeVord, Pamela; Cavanaugh, John M

    2015-01-01

    Blast induced neurotrauma has been the signature wound in returning soldiers from the ongoing wars in Iraq and Afghanistan. Of importance is understanding the pathomechansim(s) of blast overpressure (OP) induced axonal injury. Although several recent animal models of blast injury indicate the neuronal and axonal injury in various brain regions, animal studies related to axonal injury in the white matter (WM) tracts of cervical spinal cord are limited. The purpose of this study was to assess the extent of axonal injury in WM tracts of cervical spinal cord in male Sprague Dawley rats subjected to a single insult of blast OP. Sagittal brainstem sections and horizontal cervical spinal cord sections from blast and sham animals were stained by neurofilament light (NF-L) chain and beta amyloid precursor protein immunocytochemistry and observed for axonal injury changes. Observations from this preliminary study demonstrate axonal injury changes in the form of prominent swellings, retraction bulbs, and putative signs of membrane disruptions in the brainstem and cervical spinal cord WM tracts of rats subjected to blast OP. Prominent axonal injury changes following the blast OP exposure in brainstem and cervical spinal WM tracts underscores the need for careful evaluation of blast induced injury changes and associated symptoms. NF-L immunocytochemistry can be considered as an additional tool to assess the blast OP induced axonal injury.

  5. The effect of blast overpressure on the mechanical properties of a chinchilla tympanic membrane.

    PubMed

    Liang, Junfeng; Yokell, Zachery A; Nakmaili, Don U; Gan, Rong Z; Lu, Hongbing

    2017-08-18

    The rupture of tympanic membrane (TM) has long been viewed as an indicator of blast injury, especially for hearing loss. However, little is known about damage to the TM caused by blast with pressure lower than the rupture threshold. In this paper, we present our study on the effect of blast overpressure on the static mechanical properties of TM. Chinchilla was used as the animal model and exposed to multiple blasts with pressures lower than the rupture threshold of the TM. Using a micro-fringe projection method, we observed the alteration of the static mechanical properties of post-blast chinchilla's TMs as compared to those of control TMs. Specifically, after exposing to multiple blasts, the Young's modulus of chinchilla TM decreased by ∼53% while the ultimate failure pressure decreased by ∼33%. Scanning Electron Microscope (SEM) images show the damage formation in the post-blast TM as compared with its control counterpart. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Effects of filament size on critical current density in overpressure processed Bi-2212 round wire.

    PubMed

    Jiang, Jianyi; Francis, Ashleigh; Alicea, Ryan; Matras, Maxime; Kametani, Fumitake; Trociewitz, Ulf P; Hellstrom, Eric E; Larbalestier, David C

    2017-06-01

    Bi2Sr2CaCu2Ox (Bi-2212) conductor is the only high temperature superconductor manufactured as a round wire and is a very promising conductor for very high field applications. One of the key design parameters of Bi-2212 wire is its filament size, which has been previously reported to affect the critical current density (Jc ) and ac losses. Work with 1 bar heat treatment showed that the optimal filament diameter was about 15 μm but it was not well understood at that time that gas bubbles were the main current limiting mechanism. Here we investigated a recent Bi-2212 wire with a 121×18 filament architecture with varying wire diameter (1.0 to 1.5 mm) using 50 bar overpressure processing. This wire is part of a 1.2 km piece length of 1.0 mm diameter made by Oxford Superconducting Technology. We found that Jc is independent of the filament size in the range from 9 to 14 μm, although the n value increased with increasing filament size. A new record Jc (4.2 K, 15 T) of 4200 A/mm(2) and JE (4.2 K, 15 T) of 830 A/mm(2) were achieved.

  7. On-line overpressure thin-layer chromatographic separation and electrospray mass spectrometric detection of glycolipids.

    PubMed

    Chai, Wengang; Leteux, Christine; Lawson, Alexander M; Stoll, Mark S

    2003-01-01

    On-line thin-layer chromatographic separation and electrospray mass spectrometry (TLC/ESI-MS) has been accomplished by direct linking of a commercial overpressure TLC instrument, OPLC 50, and a Q-TOF mass spectrometer. Mass spectrometric detection sensitivity and chromatographic resolution achieved by this configuration were assessed using acidic glycolipids as examples. Under the optimized conditions, a sensitivity of 5 pmol of glycosphingolipid was readily demonstrated for TLC/ESI-MS and 20 pmol for TLC/ESI-MS/MS production scanning to derive the saccharide sequence and long chain base/fatty acid composition of the ceramide. Initial preconditioning of TLC plates is necessary to achieve high sensitivity detection by reducing chemical background noise. Plates can be used repeatedly (at least 10 times) for analysis, although this may result in a minor reduction in TLC resolution. Following solvent development, separated components on the TLC plates can be detected in the conventional way by nondestructive staining or UV absorption or fluorescence and can be stored for on-line TLC/ESI-MS analysis at a later stage without reduction in mass spectrometric detection sensitivity and chromatographic resolution. Aspects for further improvement of OPLC instrumentation include use of narrower TLC plate dimensions and refined design of the eluate exit system.

  8. Blast overpressure induced structural and functional changes in the auditory system.

    PubMed

    Patterson, J H; Hamernik, R P

    1997-07-25

    Blast overpressure of sufficient intensity can produce injury to various organ systems. Unprotected ears result in the auditory system being the most susceptible. The injuries to the auditory system include: rupture of the tympanic membrane, dislocation or fracture of the ossicular chain, and damage to the sensory structures on the basilar membrane. All these injuries can be characterized as a form of mechanical damage to the affected structure. Injury to the sensory structures on the basilar membrane leads to temporary and permanent loss of hearing sensitivity. The temporary component of the hearing loss shows a time course after removal from the noise which frequently will include an initial increase in hearing loss followed by a recovery period during which threshold may return to preexposure levels or stabilize at a higher level which represents a permanent loss of hearing sensitivity. This type of recovery function suggests that there are damage processes which continue after the traumatic event and that intervention might mitigate some of the damage and hearing loss.

  9. A proposed biochemical mechanism involving hemoglobin for blast overpressure-induced injury.

    PubMed

    Elsayed, N M; Gorbunov, N V; Kagan, V E

    1997-07-25

    Blast overpressure (BOP) is the abrupt, rapid, rise in atmospheric pressure resulting from explosive detonation, firing of large-caliber weapons, and accidental occupational explosions. Exposure to incident BOP waves causes internal injuries, mostly to the hollow organs, particularly the ears, lungs and gastrointestinal tract. BOP-induced injury used to be considered of military concern because it occurred mostly in military environments during military actions or training, and to a lesser extent during civilian occupational accidents. However, in recent years with the proliferation of indiscriminate terrorist bombings worldwide involving civilians, blast injury has become a societal concern, and the need to understand the biochemical and molecular mechanism(s) of injury, and to find new and effective methods for treatment gained importance. In general, past BOP research has focused on the physiological and pathological manifestations of incapacitation, thresholds of safety, and on predictive modeling. However, we have been studying the molecular mechanism of BOP-induced injury, and recently began to have an insight into that mechanism, and recognize the role of hemoglobin released during hemorrhage in catalyzing free radical reactions leading to oxidative stress. In this report we discuss the biochemical changes observed after BOP exposure in rat blood and lung tissue, and propose a biochemical mechanism for free radical-induced oxidative stress that can potentially complicate the injury. Moreover, we observed that some antioxidants can interact with Hb oxidation products (oxy-, met- and oxoferrylHb) and act as prooxidants that can increase the damage rather than decrease it.

  10. Antifungal metabolites from the roots of Diospyros virginiana by overpressure layer chromatography.

    PubMed

    Wang, Xiaoning; Habib, Eman; León, Francisco; Radwan, Mohamed M; Tabanca, Nurhayat; Gao, Jiangtao; Wedge, David E; Cutler, Stephen J

    2011-12-01

    A preparative overpressure layer chromatography (OPLC) method was successfully used for the separation of two new natural compounds, 4-hydroxy-5,6-dimethoxynaphthalene-2-carbaldehyde (1) and 12,13-didehydro-20,29-dihydrobetulin (2) together with nine known compounds, including 7-methyljuglone (3), diospyrin (4), isodiospyrin (5), shinanolone (6), lupeol (7), betulin (8), betulinic acid (9), betulinaldehyde (10), and ursolic acid (11) from the acetone extract of the roots of Diospyros virginiana. Their identification was accomplished by 1D- and 2D-NMR spectroscopy and HR-ESI-MS methods. All the isolated compounds were evaluated for their antifungal activities against Colletotrichum fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and P. viticola using in vitro micro-dilution broth assay. The results indicated that compounds 3 and 5 showed high antifungal activity against P. obscurans at 30 μM with 97.0 and 81.4% growth inhibition, and moderate activity against P. viticola (54.3 and 36.6%). It appears that an optimized OPLC system offers a rapid and efficient method of exploiting bioactive natural products. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  11. No neurochemical evidence of brain injury after blast overpressure by repeated explosions or firing heavy weapons.

    PubMed

    Blennow, K; Jonsson, M; Andreasen, N; Rosengren, L; Wallin, A; Hellström, P A; Zetterberg, H

    2011-04-01

    Psychiatric and neurological symptoms are common among soldiers exposed to blast without suffering a direct head injury. It is not known whether such symptoms are direct consequences of blast overpressure. To examine if repeated detonating explosions or firing if of heavy weapons is associated with neurochemical evidence of brain damage. Three controlled experimental studies. In the first, army officers were exposed to repeated firing of a FH77B howitzer or a bazooka. Cerebrospinal fluid (CSF) was taken post-exposure to measure biomarkers for brain damage. In the second, officers were exposed for up to 150 blasts by firing a bazooka, and in the third to 100 charges of detonating explosives of 180 dB. Serial serum samples were taken after exposure. Results were compared with a control group consisting of 19 unexposed age-matched healthy volunteers. The CSF biomarkers for neuronal/axonal damage (tau and neurofilament protein), glial cell injury (GFAP and S-100b), blood-brain barrier damage (CSF/serum albumin ratio) and hemorrhages (hemoglobin and bilirubin) and the serum GFAP and S-100b showed normal and stable levels in all exposed officers. Repeated exposure to high-impact blast does not result in any neurochemical evidence of brain damage. These findings are of importance for soldiers regularly exposed to high-impact blast when firing artillery shells or other types of heavy weapons. © 2010 John Wiley & Sons A/S.

  12. Antifungal Metabolites from the Roots of Diospyros virginiana by Overpressure Layer Chromatography

    PubMed Central

    Wang, Xiaoning; Habib, Eman; León, Francisco; Radwan, Mohamed M.; Tabanca, Nurhayat; Gao, Jiangtao

    2011-01-01

    A preparative overpressure layer chromatography (OPLC) method was successfully used for the separation of two new natural compounds, 4-hydroxy-5,6-dimethoxy-2-naphthaldehyde (1) and Δ12,13-20,29-dihydrobetulin (2) together with nine known compounds including 7-methyl-juglone (3), diospyrin (4), isodiospyrin (5), shinanolone (6), lupeol (7), betulin (8), betulinic acid (9), betulinaldehyde (10), and ursolic acid (11) from the acetone extract of the roots of Diospyros virginiana. Their identification was performed with mono and bidimensional NMR spectroscopy and HR-ESI-MS methods. All the isolated compounds were evaluated for their antifungal activity against Colletotrichum fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and P. viticola using in vitro micro-dilution broth assay. The results indicated that compounds 3 and 5 showed high antifungal activity against P. obscurans at 30 μM with 97.0 % and 81.4 % growth inhibition and moderate activity against P. viticola (54.3 % and 36.6 %). It appears that an optimized OPLC system offers a rapid and efficient method of exploiting bioactive natural products. PMID:22162171

  13. Blast overpressure induced axonal injury changes in rat brainstem and spinal cord

    PubMed Central

    Kallakuri, Srinivasu; Purkait, Heena S.; Dalavayi, Satya; VandeVord, Pamela; Cavanaugh, John M.

    2015-01-01

    Introduction: Blast induced neurotrauma has been the signature wound in returning soldiers from the ongoing wars in Iraq and Afghanistan. Of importance is understanding the pathomechansim(s) of blast overpressure (OP) induced axonal injury. Although several recent animal models of blast injury indicate the neuronal and axonal injury in various brain regions, animal studies related to axonal injury in the white matter (WM) tracts of cervical spinal cord are limited. Objective: The purpose of this study was to assess the extent of axonal injury in WM tracts of cervical spinal cord in male Sprague Dawley rats subjected to a single insult of blast OP. Materials and Methods: Sagittal brainstem sections and horizontal cervical spinal cord sections from blast and sham animals were stained by neurofilament light (NF-L) chain and beta amyloid precursor protein immunocytochemistry and observed for axonal injury changes. Results: Observations from this preliminary study demonstrate axonal injury changes in the form of prominent swellings, retraction bulbs, and putative signs of membrane disruptions in the brainstem and cervical spinal cord WM tracts of rats subjected to blast OP. Conclusions: Prominent axonal injury changes following the blast OP exposure in brainstem and cervical spinal WM tracts underscores the need for careful evaluation of blast induced injury changes and associated symptoms. NF-L immunocytochemistry can be considered as an additional tool to assess the blast OP induced axonal injury. PMID:26752889

  14. Delineating Area of Review in a System with Pre-injection Relative Overpressure

    DOE PAGES

    Oldenburg, Curtis M.; Cihan, Abdullah; Zhou, Quanlin; ...

    2014-12-31

    The Class VI permit application for geologic carbon sequestration (GCS) requires delineation of an area of review (AoR), defined as the region surrounding the (GCS) project where underground sources of drinking water (USDWs) may be endangered. The methods for estimating AoR under the Class VI regulation were developed assuming that GCS reservoirs would be in hydrostatic equilibrium with overlying aquifers. Here we develop and apply an approach to estimating AoR for sites with preinjection relative overpressure for which standard AoR estimation methods produces an infinite AoR. The approach we take is to compare brine leakage through a hypothetical open flowmore » path in the base-case scenario (no-injection) to the incrementally larger leakage that would occur in the CO2-injection case. To estimate AoR by this method, we used semi-analytical solutions to single-phase flow equations to model reservoir pressurization and flow up (single) leaky wells located at progressively greater distances from the injection well. We found that the incrementally larger flow rates for hypothetical leaky wells located 6 km and 4 km from the injection well are ~20% and 30% greater, respectively, than hypothetical baseline leakage rates. If total brine leakage is considered, the results depend strongly on how the incremental increase in total leakage is calculated, varying from a few percent to up to 40% greater (at most at early time) than base-case total leakage.« less

  15. Prediction of blast-induced air overpressure: a hybrid AI-based predictive model.

    PubMed

    Jahed Armaghani, Danial; Hajihassani, Mohsen; Marto, Aminaton; Shirani Faradonbeh, Roohollah; Mohamad, Edy Tonnizam

    2015-11-01

    Blast operations in the vicinity of residential areas usually produce significant environmental problems which may cause severe damage to the nearby areas. Blast-induced air overpressure (AOp) is one of the most important environmental impacts of blast operations which needs to be predicted to minimize the potential risk of damage. This paper presents an artificial neural network (ANN) optimized by the imperialist competitive algorithm (ICA) for the prediction of AOp induced by quarry blasting. For this purpose, 95 blasting operations were precisely monitored in a granite quarry site in Malaysia and AOp values were recorded in each operation. Furthermore, the most influential parameters on AOp, including the maximum charge per delay and the distance between the blast-face and monitoring point, were measured and used to train the ICA-ANN model. Based on the generalized predictor equation and considering the measured data from the granite quarry site, a new empirical equation was developed to predict AOp. For comparison purposes, conventional ANN models were developed and compared with the ICA-ANN results. The results demonstrated that the proposed ICA-ANN model is able to predict blast-induced AOp more accurately than other presented techniques.

  16. Beam-Beam Interactions

    SciTech Connect

    Sramek, Christopher

    2003-09-05

    At the interaction point of a particle accelerator, various phenomena occur which are known as beam-beam effects. Incident bunches of electrons (or positrons) experience strong electromagnetic fields from the opposing bunches, which leads to electron deflection, beamstrahlung and the creation of electron/positron pairs and hadrons due to two-photon exchange. In addition, the beams experience a ''pinch effect'' which focuses each beam and results in either a reduction or expansion of their vertical size. Finally, if a beam's disruption parameter is too large, the beam can develop a sinusoidal distortion, or two-stream (kink) instability. This project simulated and studied these effects as they relate to luminosity, deflection angles and energy loss in order to optimize beam parameters for the Next Linear Collider (NLC). Using the simulation program Guinea-Pig, luminosity, deflection angle and beam energy data was acquired for different levels of beam offset and distortion. Standard deflection curves and luminosity plots agreed with theoretical models but also made clear the difficulties of e-e- feedback. Simulations emphasizing kink instability in modulated and straight beam collisions followed qualitative behavioral predictions and roughly fit recent analytic calculations. Finally, a study of e-e- collisions under design constraints for the NLC provided new estimates of how luminosity, beamstrahlung energy loss, upsilon parameter and deflection curve width scale with beam spotsizes.

  17. CFD Assessment of Forward Booster Separation Motor Ignition Overpressure on ET XT 718 Ice/Frost Ramp

    NASA Technical Reports Server (NTRS)

    Tejnil, Edward; Rogers, Stuart E.

    2012-01-01

    Computational fluid dynamics assessment of the forward booster separation motor ignition over-pressure was performed on the space shuttle external tank X(sub T) 718 ice/frost ramp using the flow solver OVERFLOW. The main objective of this study was the investigation of the over-pressure during solid rocket booster separation and its affect on the local pressure and air-load environments. Delta pressure and plume impingement were investigated as a possible contributing factor to the cause of the debris loss on shuttle missions STS-125 and STS-127. A simplified computational model of the Space Shuttle Launch Vehicle was developed consisting of just the external tank and the solid rocket boosters with separation motor nozzles and plumes. The simplified model was validated by comparison to full fidelity computational model of the Space Shuttle without the separation motors. Quasi steady-state plume solutions were used to calibrate the thrust of the separation motors. Time-accurate simulations of the firing of the booster-separation motors were performed. Parametric studies of the time-step size and the number of sub-iterations were used to find the best converged solution. The computed solutions were compared to previous OVERFLOW steady-state runs of the separation motors with reaction control system jets and to ground test data. The results indicated that delta pressure from the overpressure was small and within design limits, and thus was unlikely to have contributed to the foam losses.

  18. Ion beam generating apparatus

    DOEpatents

    Brown, Ian G.; Galvin, James

    1987-01-01

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam.

  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. 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.

  1. Compact vacuum insulation embodiments

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    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.

  2. 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.

  3. Compact vacuum insulation embodiments

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1992-04-28

    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. 26 figs.

  4. Integrated structure vacuum tube

    NASA Technical Reports Server (NTRS)

    Dimeff, J.; Kerwin, W. J. (Inventor)

    1976-01-01

    High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

  5. Edison's vacuum technology patents

    NASA Astrophysics Data System (ADS)

    Waits, Robert K.

    2003-07-01

    During 1879 Thomas Edison's Menlo Park, New Jersey laboratory developed the means to evacuate glass lamp globes to less than a mTorr in 20 min and in mid-1880 began production of carbon-filament incandescent lamps. Among Edison's nearly 1100 U.S. patents are five for vacuum pump improvements, and at least eight others that are vacuum-related; all applied for between 1880 and 1886. Inspired by an 1878 article by De La Rue and Müller [Philos. Trans. R. Soc. London, Ser. A 169, 155 (1878)] on studies of glow discharges, Edison devised a combination pump using the Geissler pump as a rough pump and the Sprengel pump for continuous exhaustion. Edison's patents described means to control the mercury flow and automate the delivery of the mercury to banks of up to a hundred pumps. Other patents described various means to remove residual gases during lamp processing.

  6. Vacuum tool manipulator

    SciTech Connect

    Zollinger, W.T.

    1992-12-31

    This invention is comprised of an apparatus for manipulating a vacuum hose in a reactor vessel comprising 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.

  7. 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.

  8. An automated vacuum system

    SciTech Connect

    Atkins, W.H. ); Vaughn, G.D. ); Bridgman, C. )

    1991-01-01

    Software tools available with the Ground Test Accelerator (GTA) control system provide the capability to express a control problem as a finite state machine. System states and transitions are expressed in terms of accelerator parameters and actions are taken based on state transitions. This is particularly useful for sequencing operations which are modal in nature or are unwieldy when implemented with conventional programming. State diagrams are automatically translated into code which is executed by the control system. These tools have been applied to the vacuum system for the GTA accelerator to implement automatic sequencing of operations. With a single request, the operator may initiate a complete pump-down sequence. He can monitor the progress and is notified if an anomaly occurs requiring intervention. The operator is not required to have detailed knowledge of the vacuum system and is protected from taking inappropriate actions. 1 ref., 6 figs.

  9. Vacuum: From Art to Exact Science.

    ERIC Educational Resources Information Center

    Lafferty, James M.

    1981-01-01

    Reviews the history of vacuum technology. Includes vacuum pump developments (mechanical, ion, and cyrogenic pumps), measurement techniques, the development of the American Vacuum Society, and electronics in vacuum technology. (JN)

  10. BEAM-BEAM 2003 SUMMARY.

    SciTech Connect

    FISCHER,W.SEN,T.

    2003-05-19

    This paper summarizes the presentations and discussions of the Beam-Beam'03 workshop, held in Montauk, Long Island, from May 19 to 23, 2003. Presentations and discussions focused on halo generation from beam-beam interactions; beam-beam limits, especially coherent limits and their effects on existing and future hadron colliders; beam-beam compensation techniques, particularly for long-range interactions; and beam-beam study tools in theory, simulation, and experiment.

  11. Betatrons with kiloampere beams

    SciTech Connect

    Peterson, J.M.

    1982-11-01

    Although the magnetic-induction method of acceleration used in the betatron is inherently capable of accelerating intense particle beams to high energy, many beam-instability questions arise when beams in the kilo-ampere range are considered. The intense electromagnetic fields produced by the beam, and by the image currents and charges induced in the surrounding walls, can produce very disruptive effects. Several unstable modes of collective oscillation are possible; the suppression of any one of them usually involves energy spread for Landau damping and careful design of the electrical character of the vacuum chamber. The various design criteria are often mutually incompatible. Space-charge detuning can be severe unless large beam apertures and high-energy injection are used. In order to have an acceptably low degree of space-charge detuning in the acceleration of a 10-kilo-ampere electron beam, for example, an injection energy on the order of 50 MeV seems necessary, in which case the forces due to nearby wall images can have a larger effect than the internal forces of the beam. A method of image compensation was invented for reducing the net image forces; it serves also to decrease the longitudinal beam impedance and thus helps alleviate the longitudinal instability as well. In order to avoid the ion-electron collective instability a vacuum in the range of 10/sup -8/ torr is required for an acceleration time of 1 millisecond. A multi-ring betatron system using the 50-MeV Advanced Test Accelerator at LLNL as an injector was conceptually designed.

  12. Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

    PubMed Central

    Wang, Bing-Yu; Hsieh, Fan-Chun; Lin, Che-Yu; Chen, Shao-En; Chen, Fong-Zhi; Wu, Chia-Che

    2014-01-01

    In this study, we develop a clamped–clamped beam-type piezoelectric vacuum pressure sensing element. The clamped–clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10−6 to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage. PMID:25421736

  13. Effect of 10 MeV E-beam irradiation combined with vacuum-packaging on the shelf life of Atlantic salmon fillets during storage at 4 °C.

    PubMed

    Yang, Zhen; Wang, Haiyan; Wang, Wei; Qi, Wenyuan; Yue, Ling; Ye, Qingfu

    2014-02-15

    Biochemical properties and gel-forming ability were investigated as a function of storage time to understand the effect of 10 MeV electron linear accelerator irradiation, combined with vacuum-packaging changes, on Atlantic salmon fillets during cold storage at 4 °C. The results showed that compared with those of the control samples, pH, water soluble protein and extractable protein were not significantly altered by irradiation. However, pH, water soluble protein and extractable protein changed notably as storage time increased. While salt soluble protein (SSP), total volatile base nitrogen (TVB-N), a(*) values, 2-thiobarbituric acid (TBA) and total viable counts (TVC) were significantly (p<0.05) affected by different irradiation doses, which inhibited the increase in TVB-N but promoted TBA values during the storage period. Moreover, irradiation up to 3 kGy did not significantly change the gel patterns, while the MHC patterns were slightly reduced with the increasing of the storage time.

  14. Vacuum deposited polymer/silver reflector material

    SciTech Connect

    Affinito, J.; Martin, P.; Gross, M.; Bennett, W.

    1994-07-01

    Weatherable, low cost, front surface, solar reflectors on flexible substrates would be highly desirable for lamination to solar concentrator panels. The method to be described in this paper may permit such reflector material to be fabricated for less than 50 cents per square foot. Vacuum deposited Polymer/Silver/Polymer reflectors and Fabry-Perot interference filters were fabricated in a vacuum web coating operation on polyester substrates. Reflectivities were measured in the wavelength range from .4 {mu}m to .8 {mu}m. It is hoped that a low cost substrate can be used with the substrate laminated to the concentrator and the weatherable acrylic polymer coating facing the sun. This technique should be capable of deposition line speeds approaching 1500 linear feet/minute. Central to this technique is a new vacuum deposition process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process - for Polymer Multi-Layer.

  15. Lifetime and Tail Simulations for Beam-Beam Effects in PEP-II B Factory

    SciTech Connect

    Shatilov, D.N.; Zholents, A.A.

    1994-12-01

    A fast tracking technique for doing beam tail simulations has been applied to a study of beam-beam effects in the SLAC/LBL/LLNL PEP-II B Factory. In particular, the dependence of beam lifetime and particle density distribution due to vacuum pressure, damping times, machine nonlinearity and parasitic crossings has been analyzed. Effects of accidental orbit separation and dispersion function at the interaction point (IP) have also been considered.

  16. How to overpressurize a magmatic chamber: the thermodynamic constraints of crystallization-gas exsolution processes

    NASA Astrophysics Data System (ADS)

    Cichy, S.; Thiéry, R.

    2012-12-01

    The pressure evolution of magmatic chambers is a key question in order to understand the triggering mechanisms and conditions of volcanic eruptions. While this subject is undoubtedly complex, a first answer was provided by the seminal model of Tait et al. (1989), which addresses the pressurization produced by simultaneous crystallization-gas exsolution. Through a set of simple equations, they succeed to tackle this problem by using salient physico-chemical parameters of interest, i.e. magma nature (mafic or felsic), bulk volatile content (H2O and CO2), crystallization variation, initial magma pressure, Henry solubility coefficients, elasticity of the magmatic chamber, melt and crystal densities. Thus, Tait et al. (1989) were able to show that coeval crystallization-gas exsolution is, indeed, an efficient process: a partial crystallization of a few percent in water-saturated magmas is sufficient to generate overpressures exceeding twice the tensile strength of the magmatic chamber. However, in other cases (CO2 or some H2O-CO2 saturated magmas), this model predicts underpressures of the magma chambers, and such a result is counterintuitive and problematic from what is known in volcanology. In fact, to our knowledge, one feature of the theory of Tait et al. has never been clearly stated in the literature: this model applies only in the case of disequilibrium growth of crystals in the magma, as no provision is made to take into account the chemical equilibrium of silicate components between solids and melt. While this simplification hypothesis is certainly valid in fast-evolving magmas (kinetic effects) it may be questioned in the case of slow crystallization at equilibrium with the melt. Thus, we have extended the algorithm of Tait et al. (1989) to deal with this new aspect. The main result is that, in all cases, significant overpressures will be generated in cooling magmas (even CO2-saturated magmas). This can be explained as follows: under the equilibrium assumption

  17. Realistic Probability Estimates For Destructive Overpressure Events In Heated Center Wing Tanks Of Commercial Jet Aircraft

    SciTech Connect

    Alvares, N; Lambert, H

    2007-02-07

    The Federal Aviation Administration (FAA) identified 17 accidents that may have resulted from fuel tank explosions on commercial aircraft from 1959 to 2001. Seven events involved JP 4 or JP 4/Jet A mixtures that are no longer used for commercial aircraft fuel. The remaining 10 events involved Jet A or Jet A1 fuels that are in current use by the commercial aircraft industry. Four fuel tank explosions occurred in center wing tanks (CWTs) where on-board appliances can potentially transfer heat to the tank. These tanks are designated as ''Heated Center Wing Tanks'' (HCWT). Since 1996, the FAA has significantly increased the rate at which it has mandated airworthiness directives (ADs) directed at elimination of ignition sources. This effort includes the adoption, in 2001, of Special Federal Aviation Regulation 88 of 14 CFR part 21 (SFAR 88 ''Fuel Tank System Fault Tolerance Evaluation Requirements''). This paper addresses SFAR 88 effectiveness in reducing HCWT ignition source probability. Our statistical analysis, relating the occurrence of both on-ground and in-flight HCWT explosions to the cumulative flight hours of commercial passenger aircraft containing HCWT's reveals that the best estimate of HCWT explosion rate is 1 explosion in 1.4 x 10{sup 8} flight hours. Based on an analysis of SFAR 88 by Sandia National Laboratories and our independent analysis, SFAR 88 reduces current risk of historical HCWT explosion by at least a factor of 10, thus meeting an FAA risk criteria of 1 accident in billion flight hours. This paper also surveys and analyzes parameters for Jet A fuel ignition in HCWT's. Because of the paucity of in-flight HCWT explosions, we conclude that the intersection of the parameters necessary and sufficient to result in an HCWT explosion with sufficient overpressure to rupture the HCWT is extremely rare.

  18. Maximal exercise performance-impairing effects of simulated blast overpressure in sheep.

    PubMed

    Januszkiewicz, A J; Mundie, T G; Dodd, K T

    1997-07-25

    Lung contusion has been identified as a primary blast injury. These experiments addressed a fundamental and overt endpoint of primary blast injury, incapacitation (performance decrement). Respiration, hemodynamics, and blood gases were measured in sheep undergoing incremental exercise challenge before and 1 h after simulated blast exposure of the thorax. Pathologic examination of lung tissue was performed after exposure and exercise testing. Blast overpressure was simulated in the laboratory using a compressed air-driven shock tube. Three levels of lung injury (Levels 1-3, 'Trivial', 'Slight', and 'Moderate' injury, respectively) were examined for effects on maximal oxygen consumption (VO[2max]), an index of cardiorespiratory fitness. Resting hemodynamics and blood gases were relatively normal an hour after exposure, immediately before exercise. However, Levels 1-3 lung injury were associated with average 4.8, 29.9 and 49.3% VO(2max). decreases, respectively. These performance decrements for Levels 2 and 3 were significantly different from respective controls (non-exposed). Exercise caused significant hemoconcentration in sheep under control conditions, before exposure (resting 9.5 +/- 0.9, end-exercise 11.8 +/- 0.9 g/100 ml). Blast exposure resulted in average decreases of 4.9 +/- 3.4, 12.8 +/- 4.0, and 12.6 +/- 3.3% in exercise-induced hemoconcentration for Levels 1-3 injury, respectively. Normal exercise-induced hemodynamic increases were also attenuated after exposure. Levels 2 and 3 injury resulted in average 22.6 +/- 2.9 and 18.5 +/- 11.2% stroke volume decreases, and also 22.3 +/- 8.4 and 29.0 +/- 14.2% cardiac output decreases, respectively, during exercise. While blast lung pathology and pulmonary function changes could account for post-blast performance decrements, these experiments suggest that in sheep, early after exposure, diminished hemoconcentration and cardiac disfunction may also contribute to decreased exercise performance.

  19. The functional and structural changes in the basilar artery due to overpressure blast injury

    PubMed Central

    Toklu, Hale Z; Muller-Delp, Judy; Yang, Zhihui; Oktay, Şehkar; Sakarya, Yasemin; Strang, Kevin; Ghosh, Payal; Delp, Michael D; Scarpace, Philip J; Wang, Kevin KW; Tümer, Nihal

    2015-01-01

    Overpressure blast-wave induced brain injury (OBI) leads to progressive pathophysiologic changes resulting in a reduction in brain blood flow, blood brain barrier breakdown, edema, and cerebral ischemia. The aim of this study was to evaluate cerebral vascular function after single and repeated OBI. Male Sprague-Dawley rats were divided into three groups: Control (Naive), single OBI (30 psi peak pressure, 1 to 2 msec duration), and repeated (days 1, 4, and 7) OBI (r-OBI). Rats were killed 24 hours after injury and the basilar artery was isolated, cannulated, and pressurized (90 cm H2O). Vascular responses to potassium chloride (KCl) (30 to 100 mmol/L), endothelin-1 (10−12 to 10−7 mol/L), acetylcholine (ACh) (10−10 to 10−4 mol/L) and diethylamine-NONO-ate (DEA-NONO-ate) (10−10 to 10−4 mol/L) were evaluated. The OBI resulted in an increase in the contractile responses to endothelin and a decrease in the relaxant responses to ACh in both single and r-OBI groups. However, impaired DEA-NONO-ate-induced vasodilation and increased wall thickness to lumen ratio were observed only in the r-OBI group. The endothelin-1 type A (ETA) receptor and endothelial nitric oxide synthase (eNOS) immunoreactivity were significantly enhanced by OBI. These findings indicate that both single and r-OBI impairs cerebral vascular endothelium-dependent dilation, potentially a consequence of endothelial dysfunction and/or vascular remodelling in basilar arteries after OBI. PMID:26104291

  20. Morphologic and biochemical characterization of brain injury in a model of controlled blast overpressure exposure.

    PubMed

    Svetlov, Stanislav I; Prima, Victor; Kirk, Daniel R; Gutierrez, Hector; Curley, Kenneth C; Hayes, Ronald L; Wang, Kevin K W

    2010-10-01

    Existing experimental approaches for studies of blast impact in small animals are insufficient and lacking consistency. Here, we present a comprehensive model, with repeatable blast signatures of controlled duration, peak pressure, and transmitted impulse, accurately reproducing blast impact in laboratory animals. Rat survival, brain pathomorphology, and levels of putative biomarkers of brain injury glial fibrillary acid protein (GFAP), neuron-specific enolase, and ubiquitin C-terminal hydrolase (UCH)-L1 were examined in brain, cerebrospinal fluid (CSF), and blood after 10 msec of 358 kPa peak overpressure blast exposure. The high-speed imaging demonstrated a strong head acceleration/jolting accompanied by typical intracranial hematomas and brain swelling. Microscopic injury was revealed by prominent silver staining in deep brain areas, including the nucleus subthalamicus zone, suggesting both diffused and focal neurodegeneration. GFAP and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), markers of astroglia and oligodendroglia, accumulated substantially in the hippocampus 24 hours after blast and persisted for 30 days postblast. However, GFAP content in the blood significantly increased 24 hours after injury, followed by a decline and subsequent accumulation in CSF in a time-dependent fashion. A similar profile is shown for UCH-L1 increase in blood, whereas increased CSF levels of UCH-L1 persisted throughout 14 days after blast and varied significantly in individual rats. Neuron-specific enolase levels in blood were significantly elevated within 24 hours and 48 hours postblast. The proposed model of controlled nonpenetrating blast in rats demonstrates the critical pathologic and biochemical signatures of blast brain injury that may be triggered by cerebrovascular responses, including blood-brain barrier disruption, glia responses, and neuroglial alterations.