Science.gov

Sample records for beam vacuum overpressure

  1. 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... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank... per square inch gauge (psig); (3) Prevent a vacuum, which generates in any tank connected to the...

  2. 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,...

  3. 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,...

  4. 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... Equipment and Installation § 39.2011 Vapor overpressure and vacuum protection—TB/ALL. (a) The cargo tank... per square inch gauge (psig); (3) Prevent a vacuum, which generates in any tank connected to the...

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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)

  2. 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.

  3. 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

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

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

    SciTech Connect

    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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Peak Overpressures for Internal Blast

    DTIC Science & Technology

    1979-06-01

    61 70 115 132 CSHSN4 012 PETN , ,fltrythritltitraitr~l. 52 56 103 110 CaNS012 HNS , Hianitrobenrene 48 57 94 112 C6N~O Peftanitrobertuaqw 56 64 107...TEMPERATURE, K FIGURE 7. Heat Capacity Ratio k (CV + R)/C for Explosion Products. pentaerythritol tetranitrate ( PETN ), an explosive approxi- mately balanced in...overpressure range, the overpressures devel- oped by a given fuel-air ratio of PETN are less than those for TNT. The internal blast yield for PETN is

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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%.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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)

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Vacuum electron acceleration and bunch compression by a flat-top laser beam.

    PubMed

    Wang, W; Wang, P X; Ho, Y K; Kong, Q; Gu, Y; Wang, S J

    2007-09-01

    The field intensity distribution and phase velocity characteristics of a flat-top laser beam are analyzed and discussed. The dynamics of electron acceleration in this kind of beam are investigated using three-dimensional test particle simulations. Compared with the standard (i.e., TEM(00) mode) Gaussian beam, a flat-top laser beam has a stronger longitudinal electric field and a larger diffraction angle. These characteristics make it easier for electrons to be trapped and accelerated by the beam. With a flat-top shape, the laser beam is also applicable to the acceleration of low energy electron and bunch compression.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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

    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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Far-field overpressure blast effects... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.229 Far-field... criteria that protect the public from any hazard associated with far field blast overpressure effects...

  15. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Far-field overpressure blast effects... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.229 Far-field... criteria that protect the public from any hazard associated with far field blast overpressure effects...

  16. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Far-field overpressure blast effects... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.229 Far-field... criteria that protect the public from any hazard associated with far field blast overpressure effects...

  17. 14 CFR 417.229 - Far-field overpressure blast effects analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Far-field overpressure blast effects... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.229 Far-field... criteria that protect the public from any hazard associated with far field blast overpressure effects...

  18. 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.

  19. 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.

  20. 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.

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. An investigation on cracking of glasspanes due to air overpressure

    SciTech Connect

    Prakash, A.J.; Nabiullah, M.; Dhar, B.B.

    1994-12-31

    The study is an approach made in simulating air overpressures induced by surface blasting from those produced during gallery blasting in the laboratory, and experiments conducted on a portable window with a view to establish the sound pressure level (SPL) for cracking of window glasspanes. Eight different strengths of commercial explosives normally being used in blasting practices, were fired in the cannon of explosive gallery. SPL recorded on the seventh channel of a digital seismograph (SINCO-6) provided with FFT facility, are compared with those produced from surface blastings conducted in different Indian geomining conditions. They are found to be similar in frequency characteristics. A model of portable window provided with two replaceable glass panes has been designed and fabricated for the experiment in the explosive gallery. Stresses developed on the glass panes and the SPL in different stages were monitored to study the threshold level of damage. The first crack has been observed in the glass panes at the SPL of 162.3 dB ({minus}3.97 Kpa) and in the 5--20 Hz frequency band.

  11. 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).

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. KEKB vacuum system

    NASA Astrophysics Data System (ADS)

    Kanazawa, K.; Kato, S.; Suetsugu, Y.; Hisamatsu, H.; Shimamoto, M.; Sato, M.; Shirai, M.

    2001-01-01

    For KEK B-factory (KEKB), two rings with a circumference of 3016 m, mainly made of copper have been constructed. One ring stores a maximum of 2.6 A positron beam with the energy at 3.5 GeV, the other stores 1.1 A, 8 GeV electron beam. These stored currents far exceed those of existing electron storage rings. The inside of a beam duct is designed to minimize an effect of beam induced fields. A gap between flanges is filled using Helicoflex as a vacuum seal. Contact force of a RF finger in a bellows is assured by the use of a spring finger. Pumping slots are backed by crossing bars to prevent the penetration of beam induced fields. To obtain a pressure of 10 -7 Pa with beam, a pumping speed is designed to realize 0.1 m 3 s -1 m -1 assuming that the photodesorption coefficient reaches 10 -6 molecules/photon. The NEG strip is used as a main pump element. Chemical polishing is applied to clean the extruded surface of copper chambers. Almost all chambers are baked before installation. Only ion pumps are baked in situ. From beginning to end, a completely oil free pumping system is used. The photodesorption coefficient at the start of the commissioning was slightly higher than expected, but the decrease of the coefficient is as expected on the whole. There is no trouble on the RF contact for bellows.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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)...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  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. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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 ...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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…

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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…

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. The vacuum system of KEKB

    NASA Astrophysics Data System (ADS)

    Kanazawa, K.; Kato, S.; Suetsugu, Y.; Hisamatsu, H.; Shimamoto, M.; Shirai, M.

    2003-02-01

    For the KEK B-factory, two rings with a circumference of 3016 m, mainly made of copper, were constructed. A gap between the flanges is filled using Helicoflex as a vacuum seal. The contact force of an RF finger in a bellows is assured by using a spring finger. Pumping slots are backed by crossing bars to prevent the penetration of beam-induced fields. To obtain a pressure of 10 -9 Torr with the beam when the photo-desorption coefficient reaches 10 -6, the design of pump layout is aimed to realize 100 ℓ s-1 m-1. NEG strips are used as the main pump. Chemical polishing is applied to clean the extruded surface of a copper chamber. Almost all chambers were baked before installation. Only ion pumps were baked in situ. The photo-desorption coefficient at the start of commissioning was slightly higher than expected, but a decrease of the coefficient is as expected on the whole. At high currents, some bellows were found to be warmed by the TE mode of beam induced fields. The effect of the electron cloud became evident, especially in the LER. Direct damage by the beam is seen at the surface of the movable mask.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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)…

  10. 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

  11. 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.

  12. 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.

  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. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  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 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.

  14. Superconducting cyclotron and its vacuum system

    NASA Astrophysics Data System (ADS)

    Sur, A.; Bhandari, R. K.

    2008-05-01

    A large superconducting cyclotron is under construction at this Centre and will be used to accelerate heavy ion beams to energy up to 80 MeV/A for light heavy ions and about 10 MeV/A for medium mass heavy ions. The vacuum system for this accelerator has several different aspects. The main acceleration chamber will be evacuated to a level of about 10-7 torr using both turbo molecular pumps and specially designed cryopanels. The surfaces exposed to this 'vacuum' are mostly made of OFE copper. The cryogenic transfer lines, to cool the cryopanels, are of several meters in length and they pass through RF resonators extending below the magnet. The cryostat that will house the superconducting coils has an annular vacuum chamber, which is evacuated to a level of approximately 10-5 torr using a turbo molecular pump. Cryopumping action starts once the coils are cooled to low temperatures. A differential pumping is provided below the RF liner that encloses the pole tip of the main magnet. The space that is pumped in this case contains epoxy-potted trim coils wound around the pole tips. Crucial interlocks are provided between the differential vacuum and the acceleration chamber vacuum to avoid distortion of the RF liner, which is made of thin copper sheets. The other important vacuum system provides thermal insulation for the liquid helium transfer lines. In this paper a brief description of the superconducting cyclotron will be given. Details of various vacuum aspects of the accelerator and the logistics of their operation will be presented. Introduction of some of the improved equipment now available and improved techniques are also discussed.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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)

  19. 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

  20. 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.

  1. 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)

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Technical Seminar: Electron Beam Forming Fabrication

    NASA Video Gallery

    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 ...

  8. 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)

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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)

  18. 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.

  19. 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…

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Reconstruction of fluid (over-)pressure evolution from sub-seismic fractures in folds and foreland basins

    NASA Astrophysics Data System (ADS)

    Beaudoin, Nicolas; Lacombe, Olivier; Bellahsen, Nicolas; Emmanuel, Laurent

    2013-04-01

    Deciphering the evolution of pressure, temperature and chemistry of fluids during fold history is a challenging problem. While temperature and chemistry of paleo-fluids can be determined using vein mineralizations in fault zones and/or in diffuse sub-seismic fracture sets, few methods exist to constrain the evolution through time of fluid pressure, especially when no hydrocarbons are encountered. This contribution aims at presenting and discussing a new approach to reconstruct the evolution of fluid pressure based on paleostress analyses. The combination of stress inversion of fault slip data and calcite twin data with rock mechanics data allows determining both the orientations and the magnitudes of principal stresses during basin evolution. Assuming no burial change through time, the comparison of the computed magnitudes of the effective vertical stress with its theoretical value (calculated with respect to the paleo-overburden and hydrostatic fluid pressure) may be used to quantitatively estimate fluid overpressure in limestones at different steps of the tectonic history. Alternatively, if hydrostatic fluid pressure is assumed to prevail in the system from step to step, results likely reflect overburden variations. The application focuses on the diffuse fracture populations observed in limestones of the famous Mississippian-Permian Madison and Phosphoria formations in Laramide basement-cored folds of the Rocky Mountains: the Sheep Mountain and the Rattlesnake Mountain anticlines (Bighorn Basin, Wyoming, USA). The location of these basement-folds on each edge of the Bighorn Basin ensures that depositional and erosional events can be neglected before folding, and thus grants the opportunity to constrain and to discuss the level of fluid overpressure during both the Sevier (thin-skinned) and Laramide (thick-skinned) related Layer-Parallel Shortening (LPS) phases at both fold scale and basin scale. Results highlight an initial fluid overpressure in limestones buried

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Evaluation of brain tissue responses because of the underwash overpressure of helmet and faceshield under blast loading.

    PubMed

    Sarvghad-Moghaddam, Hesam; Rezaei, Asghar; Ziejewski, Mariusz; Karami, Ghodrat

    2017-01-01

    Head protective tools such as helmets and faceshields can induce a localized high pressure region on the skull because of the underwash of the blast waves. Whether this underwash overpressure can affect the brain tissue response is still unknown. Accordingly, a computational approach was taken to confirm the incidence of underwash with regards to blast direction, as well as examine the influence of this effect on the mechanical responses of the brain. The variation of intracranial pressure (ICP) as one of the major injury predictors, as well as the maximum shear stress were mainly addressed in this study. Using a nonlinear finite element (FE) approach, generation and interaction of blast waves with the unprotected, helmeted, and fully protected (helmet and faceshield protected) FE head models were modeled using a multi-material arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The underwash incidence overpressure was found to greatly change with the blast direction. Moreover, while underwash induced ICP (U-ICP) did not exceed the peak ICP of the unprotected head, it was comparable and even more than the peak ICP imposed on the protected heads by the primary shockwaves (Coup-ICP). It was concluded that while both helmet and faceshield protected the head against blast waves, the underwash overpressure affected the brain tissue response and altered the dynamic load experienced by the brain as it led to increased ICP levels at the countercoup site, imparted elevated skull flexure, and induced high negative pressure regions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. 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)

  5. Effects of Blast Overpressure on Neurons and Glial Cells in Rat Organotypic Hippocampal Slice Cultures

    PubMed Central

    Miller, Anna P.; Shah, Alok S.; Aperi, Brandy V.; Budde, Matthew D.; Pintar, Frank A.; Tarima, Sergey; Kurpad, Shekar N.; Stemper, Brian D.; Glavaski-Joksimovic, Aleksandra

    2015-01-01

    Due to recent involvement in military conflicts, and an increase in the use of explosives, there has been an escalation in the incidence of blast-induced traumatic brain injury (bTBI) among US military personnel. Having a better understanding of the cellular and molecular cascade of events in bTBI is prerequisite for the development of an effective therapy that currently is unavailable. The present study utilized organotypic hippocampal slice cultures (OHCs) exposed to blast overpressures of 150 kPa (low) and 280 kPa (high) as an in vitro bTBI model. Using this model, we further characterized the cellular effects of the blast injury. Blast-evoked cell death was visualized by a propidium iodide (PI) uptake assay as early as 2 h post-injury. Quantification of PI staining in the cornu Ammonis 1 and 3 (CA1 and CA3) and the dentate gyrus regions of the hippocampus at 2, 24, 48, and 72 h following blast exposure revealed significant time dependent effects. OHCs exposed to 150 kPa demonstrated a slow increase in cell death plateauing between 24 and 48 h, while OHCs from the high-blast group exhibited a rapid increase in cell death already at 2 h, peaking at ~24 h post-injury. Measurements of lactate dehydrogenase release into the culture medium also revealed a significant increase in cell lysis in both low- and high-blast groups compared to sham controls. OHCs were fixed at 72 h post-injury and immunostained for markers against neurons, astrocytes, and microglia. Labeling OHCs with PI, neuronal, and glial markers revealed that the blast-evoked extensive neuronal death and to a lesser extent loss of glial cells. Furthermore, our data demonstrated activation of astrocytes and microglial cells in low- and high-blasted OHCs, which reached a statistically significant difference in the high-blast group. These data confirmed that our in vitro bTBI model is a useful tool for studying cellular and molecular changes after blast exposure. PMID:25729377

  6. Effects of blast overpressure on neurons and glial cells in rat organotypic hippocampal slice cultures.

    PubMed

    Miller, Anna P; Shah, Alok S; Aperi, Brandy V; Budde, Matthew D; Pintar, Frank A; Tarima, Sergey; Kurpad, Shekar N; Stemper, Brian D; Glavaski-Joksimovic, Aleksandra

    2015-01-01

    Due to recent involvement in military conflicts, and an increase in the use of explosives, there has been an escalation in the incidence of blast-induced traumatic brain injury (bTBI) among US military personnel. Having a better understanding of the cellular and molecular cascade of events in bTBI is prerequisite for the development of an effective therapy that currently is unavailable. The present study utilized organotypic hippocampal slice cultures (OHCs) exposed to blast overpressures of 150 kPa (low) and 280 kPa (high) as an in vitro bTBI model. Using this model, we further characterized the cellular effects of the blast injury. Blast-evoked cell death was visualized by a propidium iodide (PI) uptake assay as early as 2 h post-injury. Quantification of PI staining in the cornu Ammonis 1 and 3 (CA1 and CA3) and the dentate gyrus regions of the hippocampus at 2, 24, 48, and 72 h following blast exposure revealed significant time dependent effects. OHCs exposed to 150 kPa demonstrated a slow increase in cell death plateauing between 24 and 48 h, while OHCs from the high-blast group exhibited a rapid increase in cell death already at 2 h, peaking at ~24 h post-injury. Measurements of lactate dehydrogenase release into the culture medium also revealed a significant increase in cell lysis in both low- and high-blast groups compared to sham controls. OHCs were fixed at 72 h post-injury and immunostained for markers against neurons, astrocytes, and microglia. Labeling OHCs with PI, neuronal, and glial markers revealed that the blast-evoked extensive neuronal death and to a lesser extent loss of glial cells. Furthermore, our data demonstrated activation of astrocytes and microglial cells in low- and high-blasted OHCs, which reached a statistically significant difference in the high-blast group. These data confirmed that our in vitro bTBI model is a useful tool for studying cellular and molecular changes after blast exposure.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Impact of blast induced transitory vibration and air-overpressure/noise on human brain--an experimental study.

    PubMed

    Raina, A K; Baheti, M; Haldar, A; Ramulu, M; Chakraborty, A K; Sahu, P B; Bandopadhayay, C

    2004-04-01

    Human response to blast induced ground vibration and air-overpressure/noise is a major concern of current mining activity. This is because the fact that mines are fast transgressing the habitats and people are getting educated. Consequently the response of humans is changing and expectedly will increase in days to come with no viable and economic alternative to blasting--an essential component of mining. The response of humans can be purely physiological or psychological in nature or combination of both depending upon the situation and conditions of mining. Where physiological response is documented in terms of effects on ears and lungs there is a meager amount or no literature available regarding effects of blasting on the brain. Moreover, the studies on transitory phenomenon like the effects of blasting on humans are rare in comparison to the whole body vibration studies. This study was designed to address the issues as a precursor to a major initiative. The preliminary investigations conducted with the monitoring of EEG responses of humans to vibration and air-overpressure/noise due to blasting revealed that there is no major response of the brain to transitory vibrations and noise.

  12. Optimal control of fuel overpressure in a polymer electrolyte membrane fuel cell with hydrogen transfer leak during load change

    NASA Astrophysics Data System (ADS)

    Ebadighajari, Alireza; DeVaal, Jake; Golnaraghi, Farid

    2017-02-01

    Formation of membrane pinholes is a common defect in fuel cells, inflicting more cost and making less durable cells. This work focuses on mitigating this issue, and offers a continuous online treatment instead of attempting to dynamically model the hydrogen transfer leak rate. This is achieved by controlling the differential pressure between the anode and cathode compartments at the inlet side of the fuel cell stack, known as the fuel overpressure. The model predictive control approach is used to attain the objectives in a Ballard 9-cell Mk1100 polymer electrolyte membrane fuel cell (PEMFC) with inclusion of hydrogen transfer leak. Furthermore, the pneumatic modeling technique is used to model the entire anode side of a fuel cell station. The hydrogen transfer leak is embedded in the model in a novel way, and is considered as a disturbance during the controller design. Experimental results for different sizes of hydrogen transfer leaks are provided to show the benefits of fuel overpressure control system in alleviating the effects of membrane pinholes, which in turn increases membrane longevity, and reduces hydrogen emissions in the eventual presence of transfer leaks. Moreover, the model predictive controller provides an optimal control input while satisfying the problem constraints.

  13. Jonah field, sublette county, Wyoming: Gas production from overpressured Upper Cretaceous Lance sandstones of the Green River basin

    USGS Publications Warehouse

    Montgomery, S.L.; Robinson, J.W.

    1997-01-01

    Jonah field, located in the northwestern Green River basin, Wyoming, produces gas from overpressured fluvial channel sandstones of the Upper Cretaceous Lance Formation. Reservoirs exist in isolated and amalgamated channel facies 10-100 ft (3-30 m) thick and 150-4000 ft (45-1210 m) wide, deposited by meandering and braided streams. Compositional and paleocurrent studies indicate these streams flowed eastward and had their source area in highlands associated with the Wyoming-Idaho thrust belt to the west. Productive sandstones at Jonah have been divided into five pay intervals, only one of which (Jonah interval) displays continuity across most of the field. Porosities in clean, productive sandstones range from 8 to 12%, with core permeabilities of .01-0.9 md (millidarcys) and in-situ permeabilities as low as 3-20 ??d (microdarcys), as determined by pressure buildup analyses. Structurally, the field is bounded by faults that have partly controlled the level of overpressuring. This level is 2500 ft (758 m) higher at Jonah field than in surrounding parts of the basin, extending to the top part of the Lance Formation. The field was discovered in 1975, but only in the 1990s did the area become fully commercial, due to improvements in fracture stimulation techniques. Recent advances in this area have further increased recoverable reserves and serve as a potential example for future development of tight gas sands elsewhere in the Rocky Mountain region.

  14. Optimal Control of Shock Tube Flow via Water Addition with Application to Ignition Overpressure Mitigation in Launch Vehicles

    NASA Astrophysics Data System (ADS)

    Moshman, Nathan

    2009-11-01

    Ignition Overpressure (IOP) in launch vehicles occurs at the start of ignition when a steep rise in pressure propagates outward from the rocket nozzle. It is crucial to minimize the overpressure so as to decrease risk of damage to the rocket body. Currently, CFD studies exist on this situation but there are no optimization studies of the water addition as a means to suppress the IOP. The proposed dissertation will use a numerical method to compute an approximate solution for an optimal control problem constrained by the one-dimensional Euler PDEs of fluid dynamics as well as volume fraction conservation. A model for inter-phase transport of mass momentum and energy and fluid interface quantities will be given. The control will be water addition from external nozzles. The adjoint system of equations will be derived and discretized. Necessary optimal conditions will be derived. An SQP method will solve an optimal situation. Predictions will be validated against shock tube experiments at the NPS rocket lab.

  15. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    NASA Astrophysics Data System (ADS)

    Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

    2013-12-01

    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

  16. Vacuum bell therapy

    PubMed Central

    Sesia, Sergio

    2016-01-01

    Background For specific therapy to correct pectus excavatum (PE), conservative treatment with the vacuum bell (VB) was introduced more than 10 years ago in addition to surgical repair. Preliminary results using the VB were encouraging. We report on our 13-year experience with the VB treatment including the intraoperative use during the Nuss procedure and present some technical innovations. Methods A VB with a patient-activated hand pump is used to create a vacuum at the anterior chest wall. Three different sizes of vacuum bells, as well as a model fitted for young women, exist. The appropriate size is selected according to the individual patient’s age and ventral surface. The device should be used at home for a minimum of 30 minutes (twice a day), and may be used up to a maximum of several hours daily. The intensity of the applied negative pressure can be evaluated with an integrated pressure gauge during follow-up visits. A prototype of an electronic model enables us to measure the correlation between the applied negative pressure and the elevation of the anterior chest wall. Results Since 2003, approx. 450 patients between 2 to 61 years of age started the VB therapy. Age and gender specific differences, depth of PE, symmetry or asymmetry, and concomitant malformations such as scoliosis and/or kyphosis influence the clinical course and success of VB therapy. According to our experience, we see three different groups of patients. Immediate elevation of the sternum was confirmed thoracoscopically during the Nuss procedure in every patient. Conclusions The VB therapy has been established as an alternative therapeutic option in selected patients suffering from PE. The initial results up to now are encouraging, but long-term results comprising more than 15 years are so far lacking, and further evaluation and follow-up studies are necessary. PMID:27747177

  17. Rolling through a vacuum

    NASA Astrophysics Data System (ADS)

    van der Schaar, Jan Pieter; Yang, I.-Sheng

    2013-12-01

    We clarify under what conditions slow-roll inflation can continue almost undisturbed, while briefly evolving through a (semi-classically) metastable false vacuum. Furthermore, we look at potential signatures in the primordial power spectrum that could point towards the existence of traversed metastable false vacua. Interestingly, the theoretical constraints for the existence of traversable metastable vacua imply that Planck should be able to detect the resulting features in the primordial power spectrum. In other words, if Planck does not see features this immediately implies the non-existence of metastable false vacua rolled through during the inflationary epoch.

  18. Avoiding Death by Vacuum

    NASA Astrophysics Data System (ADS)

    Barroso, A.; Ferreira, P. M.; Ivanov, I.; Santos, R.; Silva, João P.

    2013-07-01

    The two-Higgs doublet model (2HDM) can have two electroweak breaking, CP-conserving, minima. The possibility arises that the minimum which corresponds to the known elementary particle spectrum is metastable, a possibility we call the "panic vacuum". We present analytical bounds on the parameters of the softly broken Peccei-Quinn 2HDM which are necessary and sufficient conditions to avoid this possibility. We also show that, for this particular model, the current LHC data already tell us that we are necessarily in the global minimum of the theory, regardless of any cosmological considerations about the lifetime of the false vacua.

  19. Thermal Vacuum Test Facility.

    DTIC Science & Technology

    1984-01-31

    tne power has a rear terminal sensor input for this Probe, use it. Otherwiseq connect the probe to the front panel. The end of the sensor should be...outlet on the front panel of the vacuum chamber. BUS CONNECTtONS: Plug the 1/0 expander card into one of the three calculator slots. Cover the other two...mating cable. Soth connectors on the slave disk are identical, so either one can be used. This cable also locks into place at each end . Connect the other

  20. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    DOEpatents

    Danby, G.T.; Jackson, J.W.

    1990-03-19

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

  1. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    DOEpatents

    Danby, Gordon T.; Jackson, John W.

    1991-01-01

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

  2. Cold vacuum chamber for diagnostics: Instrumentation and first results

    NASA Astrophysics Data System (ADS)

    Gerstl, S.; Voutta, R.; Casalbuoni, S.; Grau, A. W.; Holubek, T.; de Jauregui, D. Saez; Bartolini, R.; Cox, M. P.; Longhi, E. C.; Rehm, G.; Schouten, J. C.; Walker, R. P.; Sikler, G.; Migliorati, M.; Spataro, B.

    2014-10-01

    For a proper design of the cryogenic layout of superconducting insertion devices it is necessary to take into account the heat load from the beam to the cold beam tube. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. COLDDIAG is designed in a flexible way, to allow its installation in different light sources. In order to study the beam heat load and the influence of the cryosorbed gas layer, the instrumentation comprises temperature sensors, pressure gauges, and mass spectrometers as well as retarding field analyzers with which it is possible to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. In this paper we describe the experimental equipment, the installation of COLDDIAG in the Diamond Light Source and selected examples of the measurements performed to show the capabilities of this unique instrument.

  3. High flux photon beam monitor

    SciTech Connect

    Mortazavi, P.; Woodle, M.; Rarback, H.; Shu, D.; Howells, M.

    1985-01-01

    We have designed two photon beam position monitors for use on our x-ray storage ring beam lines. In both designs, a pair of tungsten blades, separated by a pre-determined gap, intercepts a small fraction of the incoming beam. Due to photoemission, an electrical signal is generated which is proportional to the amount of beam intercepted. The thermal load deposited in the blade is transferred by a heat pipe to a heat exchanger outside the vacuum chamber. A prototype monitor with gap adjustment capability was fabricated and tested at a uv beam line. The results show that the generated electrical signal is a good measurement of the photon beam position. In the following sections, design features and test results are discussed.

  4. Beam-beam simulations for separated beams

    SciTech Connect

    Furman, Miguel A.

    2000-04-10

    We present beam-beam simulation results from a strong-strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced by the beam-beam collisions is readily obtained and offers a good opportunity for experimental comparisons. Although our results for the emittance blowup are preliminary, we conclude that, for nominal parameter values, there is no significant difference between separated beams and center-on-center collisions.

  5. Vacuum Insulator Development for the Dielectric Wall Accelerator

    SciTech Connect

    Harris, J R; Blackfield, D; Caporaso, G J; Chen, Y; Hawkins, S; Kendig, M; Poole, B; Sanders, D M; Krogh, M; Managan, J E

    2008-03-17

    At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.

  6. MOLECULAR VACUUM PUMP

    DOEpatents

    Eckberg, E.E.

    1960-09-27

    A multiple molecular vacuum pump capable of producing a vacuum of the order of 10/sup -9/ mm Hg is described. The pump comprises a casing of an aggregate of paired and matched cylindrical plates, a recessed portion on one face of each plate concentrically positioned formed by a radially extending wall and matching the similarly recessed portion of its twin plate of that pair of plates and for all paired and matched plates; a plurality of grooves formed in the radially extending walls of each and all recesses progressing in a spiral manner from their respective starting points out at the periphery of the recess inwardly to the central area; a plurality of rotors rotatably mounted to closely occupy the spaces as presented by the paired and matched recesses between all paired plates; a hollowed drive-shaft perforated at points adjacent to the termini of all spiral grooves; inlet ports at the starting points of all grooves and through all plates at common points to each respectively; and a common outlet passage presented by the hollow portion of the perforated hollowed drive-shaft of the molecular pump. (AEC)

  7. Motor actuated vacuum door

    NASA Astrophysics Data System (ADS)

    Hanagud, A. V.

    1986-10-01

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

  8. Portable vacuum object handling device

    DOEpatents

    Anderson, G.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. 1 fig.

  9. Overview of High Power Vacuum Dry RF Load Designs

    SciTech Connect

    Krasnykh, Anatoly

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  10. Vacuum window glazings for energy-efficient buildings

    SciTech Connect

    Benson, D.K.; Smith, L.K.; Tracy, C.E.; Potter, T.; Christensen, C. ); Soule, D.E. )

    1990-05-01

    The technical feasibility of a patented, laser-welded, evacuated insulating window was studied. The window has two edge-sealed sheets of glass separated by 0.5-mm glass spheres spaced 30 mm apart in a regular array. A highly insulating frame is required and several designs were analyzed. The vacuum window's combination of high solar transmittance and low thermal conductance makes it superior to many other windows in cold climates. In the US Pacific Northwest, the vacuum window could save about 6 MJ of heating energy annually per square meter of window in comparison to conventional, double-glazed windows. A large, vacuum laser-welding facility was designed and installed to conduct glass welding experiments and to fabricate full-sized vacuum windows. Experiments confirmed the feasibility of laser-sealing glass in vacuum but identified two difficulties. Under some circumstances, bubbles of dissolved gases form during welding and weaken the seal. Glass also vaporizes and contaminates the laser beam steering mirror. A novel moving metal foil mirror was developed to circumvent the contamination problem, but it has not yet been used to complete welding experiments and fabricate full-sized vacuum windows. 63 refs., 53 figs., 19 tabs.

  11. Vacuum leak detector and method

    DOEpatents

    Edwards, Jr., David

    1983-01-01

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

  12. Photoelectron photoion molecular beam spectroscopy

    SciTech Connect

    Trevor, D.J.

    1980-12-01

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed.

  13. LIGO vacuum system study

    NASA Technical Reports Server (NTRS)

    Livas, Jeffrey C.; Moore, Boude C.

    1988-01-01

    A laser interferometer gravitational wave observatory (LIGO) is being developed with sensitivities which will have a high probability of detecting gravitational waves from astrophysical sources. A major component of LIGO is a total of 16 km of 1.2 m (48 inch) diameter tube at a pressure of less than 10 to the minus 8th power torr. It will be of 304L stainless steel procured directly from the steel mills with the initial hydrogen content specially reduced. Projections of the outgassing rates of hydrogen and of water vapor as a function of time are given and the uncertainties discussed. Based on these, a preliminary analysis of the vacuum system is presented.

  14. ULTRA HIGH VACUUM VALVE

    DOEpatents

    Fry, W.A.

    1962-05-29

    A valve for high vacuum applications such as the CStellarator where chamber pressures as low as 2 x 10/sup -10/ mm Hg are necessary is designed with a line-of-sight path through the valve for visual inspection of the contents of reactants in such chambers. The valve comprises a turnable resilient metal ball having an aperture therethrough, means for selectively turning the ball to rotate the axis of its line-of-sight path, and soft, deformable opposing orifices that are movable relatively toward said ball to seal with opposite ball surfaces upon said movement of said axis of said line-of-sight path. The valve also includes a bellows seal connected between said orifices and internal actuating means that eliminates the requirement for gasketed turnable valve closing stems. (AEC)

  15. THERMOCOUPLE VACUUM GAUGE

    DOEpatents

    Price, G.W.

    1954-08-01

    A protector device is described for use in controlling the pressure within a cyclotron. In particular, an electrical circuit functions to actuate a vacuum pump when a predetermined low pressure is reached and disconnect the pump when the pressure increases abcve a certain value. The principal feature of the control circuit lies in the use of a voltage divider network at the input to a relay control tube comprising two parallel, adjustable resistances wherein one resistor is switched into the circuit when the relay connects the pump to a power source. With this arrangement the relay is energized at one input level received from a sensing element within the cyclotron chamber and is de-energized when a second input level, representing the higher pressure limit, is reached.

  16. Vacuum Energy Sequestering and Graviton Loops.

    PubMed

    Kaloper, Nemanja; Padilla, Antonio

    2017-02-10

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  17. Vacuum Energy Sequestering and Graviton Loops

    NASA Astrophysics Data System (ADS)

    Kaloper, Nemanja; Padilla, Antonio

    2017-02-01

    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  18. Breather cloth for vacuum curing

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1979-01-01

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

  19. Multipurpose Vacuum Induction Processing System

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  20. Vacuum Enhanced Cutaneous Biopsy Instrument

    SciTech Connect

    Collins, Joseph

    1999-06-25

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

  1. Purifying Aluminum by Vacuum Distillation

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1985-01-01

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

  2. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, J.D.; Gross, M.E.

    1997-10-28

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  3. Vacuum flash evaporated polymer composites

    DOEpatents

    Affinito, John D.; Gross, Mark E.

    1997-01-01

    A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

  4. Vacuum Gas Tungsten Arc Welding

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  5. Vacuum enhanced cutaneous biopsy instrument

    DOEpatents

    Collins, Joseph

    2000-01-01

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

  6. Current state of knowledge on the behavior of steel liners in concrete containments subjected to overpressurization loads

    SciTech Connect

    von Riesemann, W.A.; Parks, M.B.

    1993-11-01

    In the United States, concrete containment buildings for commercial nuclear power plants have steel liners that act as the intemal pressure boundary. The liner abuts the concrete, acting as the interior concrete form. The liner is attached to the concrete by either studs or by a continuous structural shape (such as a T-section or channel) that is either continuously or intermittently welded to the liner. Studs are commonly used in reinforced concrete containments, while prestressed containments utilize a structural element as the anchorage. The practice in some countries follows the US practice, while in other countries the containment does not have a steel liner. In this latter case, there is a true double containment, and the annular region between the two containments is vented. This paper will review the practice of design of the liner system prior to the consideration of severe accident loads (overpressurization loads beyond the design conditions).

  7. The PEP-II Lower Pressure HER Vacuum Chamber

    SciTech Connect

    DeBarger, S.; Metcalfe, S.; Seeman, J.; Sullivan, M.; Wienands, U.; Wright, D.; /SLAC

    2006-03-13

    This new vacuum chamber has been installed from 12 to 21 meters upstream of the BaBar detector in the PEP-II High Energy Ring (HER) to reduce lost particle backgrounds. The backgrounds from HER now dominate the backgrounds in the BaBar detector and the present vacuum pressure is 1 x 10{sup -9} Torr. The new chamber will increase the pumping significantly by adding 18 x 2000 l/s titanium sublimation pumps to the existing 5 x 440 l/s ion pumps, and is expected to reduce the pressure by about a factor of five. Features of the chamber include improved water cooling, improved vacuum conductance through copper RF screens featuring over 15,000 small square holes and the ability to sublimate titanium while the beam is still on.

  8. HOM Sensitivity in the PEP-II HER Vacuum Chamber

    SciTech Connect

    Weathersby, Stephen; Novokhatski, Alexander; Sullivan, Mike; /SLAC

    2010-02-10

    Synchrotron radiation is the main source of vacuum chamber heating in the PEP-II storage ring collider. This heating is reduced substantially as lattice energy is lowered. Energy scans over {Upsilon} energy states were performed by varying the high energy ring (HER) lattice energy at constant gap voltage and frequency. We observed unexpected temperature rise at particular locations when HER lattice energy was lowered from 8.6 GeV ({Upsilon}(3S)) to 8.0 GeV ({Upsilon}(2S)) while most other temperatures decreased. Bunch length measurements reveal a shorter bunch at the lower energy. The shortened bunch overheated a beam position monitoring electrode causing a vacuum breach. We explain the unexpected heating as a consequence of increased higher order mode (HOM) power generated by a shortened bunch. In this case, temperature rise helps to identify HOM sources and HOM sensitive vacuum chamber elements. Reduction of gap voltage helps to reduce this unexpected heating.

  9. Ion-beam assisted, electron-beam physical vapor deposition

    SciTech Connect

    Singh, J.

    1996-12-01

    Electron beam-physical vapor deposition (EB-PVD) is a relatively new technology that has overcome some of the difficulties associated with chemical vapor deposition, physical vapor deposition, and thermal spray processes. In the EB-PVD process, focused high-energy electron beams generated from electron guns are directed to melt and evaporate ingots, as well as preheat the substrate inside a vacuum chamber. By adding the assistance of ion beams to the process, coating density and adhesion are improved, while costs are reduced. This article describes physical vapor deposition and ion-beam processes, explains the advantages of EB-PVD, shows how ion beams optimize the benefits of EB-PVD, and enumerates a variety of applications.

  10. Bubbling the false vacuum away

    SciTech Connect

    Gleiser, M.; Rogers, B.; Thorarinson, J.

    2008-01-15

    We investigate the role of nonperturbative, bubblelike inhomogeneities on the decay rate of false-vacuum states in two- and three-dimensional scalar field theories. The inhomogeneities are induced by setting up large-amplitude oscillations of the field about the false vacuum, as, for example, after a rapid quench or in certain models of cosmological inflation. We show that, for a wide range of parameters, the presence of large-amplitude bubblelike inhomogeneities greatly accelerates the decay rate, changing it from the well-known exponential suppression of homogeneous nucleation to a power-law suppression. It is argued that this fast, power-law vacuum decay--known as resonant nucleation--is promoted by the presence of long-lived oscillons among the nonperturbative fluctuations about the false vacuum. A phase diagram is obtained distinguishing three possible mechanisms for vacuum decay: homogeneous nucleation, resonant nucleation, and crossover. Possible applications are briefly discussed.

  11. Hadron Contribution to Vacuum Polarisation

    NASA Astrophysics Data System (ADS)

    Davier, M.; Hoecker, A.; Malaescu, B.; Zhang, Z.

    2016-10-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle-antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e- annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingredients to high precision tests of the Standard Theory.

  12. Observation of Beam ION Instability in Spear3

    SciTech Connect

    Teytelman, D.; Cai, Y.; Corbett, W.J.; Raubenheimer, T.O.; Safranek, J.A.; Schmerge, J.F.; Sebek, J.J.; Wang, L.; /SLAC

    2011-12-14

    Weak vertical coupled bunch instability with oscillation amplitude at {mu}m level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail. In an electron accelerator, ions generated from the residual gas molecules can be trapped by the beam. Then these trapped ions interact resonantly with the beam and cause beam instability and emittance blow-up. Most existing light sources use a long single bunch train filling pattern, followed by a long gap to avoid multi-turn ion trapping. However, such a gap does not preclude ions from accumulating during one passage of the single bunch train beam, and those ions can still cause a Fast Ion Instability (FII) as predicted by Raubenheimer and Zimmermann. FII has been observed in ALS, and PLS by artificially increasing the vacuum pressure by injecting helium gas into the vacuum chamber or by turning off the ion pumps in order to observe the beam ion instability. In some existing rings, for instance B factory, the beam ion instability was observed at the beginning of the machine operation after a long period of shutdown and then it automatically disappeared when the vacuum was better. However, when the beam emittance becomes smaller, the FII can occur at nominal conditions as observed in PLS, SOLEIL and SSRF. This paper reports the observations of beam ion instabilities in SPEAR3 under different condition during a period of one

  13. Device and method for electron beam heating of a high density plasma

    DOEpatents

    Thode, L.E.

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10/sup 17/ to 10/sup 20/.

  14. Proposed Physics Experiments for Laser-Driven Electron Linear Acceleration in a Dielectric Loaded Vacuum, Final Report

    SciTech Connect

    Byer, Robert L.

    2016-07-08

    This final report summarizes the last three years of research on the development of advanced linear electron accelerators that utilize dielectric wave-guide vacuum channels pumped by high energy laser fields to accelerate beams of electrons.

  15. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake...

  16. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake...

  17. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake...

  18. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake...

  19. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake...

  20. Microfabricated Millimeter-Wave High-Power Vacuum Electronic Amplifiers

    DTIC Science & Technology

    2015-01-01

    Research Laboratory is demonstrating and developing millimeter-wave vacuum electronic traveling wave tube amplifiers at W- and G-band in the 10’s to 100...much promise for fabricating millimeter-wave (mmW) and sub- mmW amplifiers [1-2]. Trends toward higher frequencies come at the expense of more...demonstrated that allow extremely high aspect ratio beam tunnels to be fabricated along with the all-copper slow-wave amplifier circuits (Patent

  1. Kinetic Simulations of Ion Beam Neutralization

    SciTech Connect

    Chang, O.; Wang, J.

    2011-05-20

    Full particle PIC simulations are performed to study the neutralization of an ion beam in the cohesionless, mesothermal regime. Simulations further confirmed that neutralization is achieved through interactions between the trapped electrons and the potential well established by the propagation of the beam front along the beam direction and is not through plasma instabilities as previous studies suggested. In the transverse direction, the process is similar to that of the expansion of mesothermal plasma into vacuum. Parametric simulations are also performed to investigate the effects of beam radius and domain boundary condition on the neutralization process. The results suggests that, while the qualitative behavior may be similar in ground tests, quantitative parameters such as the beam potential will be affected significantly by the vacuum chamber because of the limits imposed on the expansion process by the finite chamber space.

  2. Vacuum phenomenon: Clinical relevance.

    PubMed

    Gohil, Ishan; Vilensky, Joel A; Weber, Edward C

    2014-04-01

    Vacuum phenomenon (VP) is an anatomical entity of potential confusion in the diagnosis and evaluation of joint pathology. Observation of this phenomenon has been demonstrated on basic radiographs, computed tomography, and magnetic resonance imaging. Although VP is most often associated with degenerative joint disease, it is observed with other pathologies. Two problematic scenarios can occur: a false-positive diagnosis of serious pathology instead of benign VP and a false-negative diagnosis of benign VP with a more serious underlying process Despite this potential for confusion, criteria for distinguishing VP from other causes of joint pain and for evaluating a suspected case of VP have not been fully established. We reviewed the literature to determine underlying mechanism, symptomology, associated pathologies, and clinical importance of VP. The formation of VP can be explained by gas solubility, pressure-volume relationships, and human physiology. CT, GRE-MRI, and multipositional views are the best imaging studies to view VP. Although most cases of VP are benign, it can be associated with clinical signs and symptoms. VP outside the spine is an underreported finding on imaging studies. VP should be on the differential diagnosis for joint pain, especially in the elderly. We have proposed criteria for diagnosing VP and generated a basic algorithm for its workup. Underreporting of this phenomenon shows a lack of awareness of VP on the part of physicians. By identifying true anatomic VP, we can prevent harm from suboptimal treatment of patients.

  3. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

  4. Compact vacuum insulation

    DOEpatents

    Benson, D.K.; Potter, T.F.

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  5. Quantum Vacuum Pathway Theory

    NASA Astrophysics Data System (ADS)

    Habegger, Eric John

    2005-02-01

    It is theorized that the quantum vacuum is a random electromagnetic field that permeates the universe. It will be shown that acceleration between a quark and a random electromagnetic energy field is an analog of the reaction between a charge moving at constant velocity with respect to an organized electromagnetic field. The difference is that with a quark any natural perpendicular deflection during that motion, as predicted by Lorentz, is contained by the strong force, which results in a change in the angular momentum of the spin of a quark. The first derivative of the equations of motion of charges in an organized electromagnetic field may be used when applied to a random electromagnetic field to invoke the same fields modeled by Maxwell's equations. Mass is intimately bound up with a quark's spin angular momentum and the energy for that increase comes directly from the local field. The underlying randomness of the local field normally remains intact through these energy exchanges but it is speculated that in a quantum entanglement, an absolute level of order is imposed on the field along a path between two particles. This causes the non local effects seen in quantum entanglement. The mechanism that may cause this effect is discussed and a simple experiment is proposed that can test the hypothesis. Also discussed are new theoretical constructs for electromagnetic radiation, mass, the skin effect, self-inductance, superposition, and gravity. The emphasis will be on an intuitive and logical approach more than a mathematical approach.

  6. Precooler Ring Vacuum System

    SciTech Connect

    Moenich, J.

    1980-10-02

    The precooler vacuum system, as proposed by FNAL, is based on a suitable modification of the existing Electron Cooling Ring System. Because of the magnetic cycle of the bending magnets, distributed ion pumping, as exists in the Electron Cooling Ring, is not applicable. Instead, the proposed pumping will be done with commercial appendage ion pumps mounted approximately every two meters around the circumference of the ring. The loss of effective pumping speed and non-uniformity of system pressure with appendage pumps may not be major considerations but the large number required does effect experimental and analytical equipment placement considerations. There is a distributed pumping technique available which: (1) is not affected by the magnetic cycle of the bending magnets; (2) will provide a minimum of four times the hydrogen pumping speed of the proposed appendage ion pumps; (3) will require no power during pumping after the strip is activated; (4) will provide the heat source for bakeout; (5) is easily replaceable; and (6) can be purchased, installed, and operated at a generous economic advantage over the presently proposed ion pumped system. The pumping technique referred to is non-evaporable gettering with ST101 Zr/Al pumping strip. A technical description of this pumping strip is given on Data Sheet 1 and 2 attached to this report.

  7. Vacuum still bottoms viscometer

    SciTech Connect

    Dinsmore, T.V.; Wilson, J.H.

    1985-01-01

    A viscometer system that is capable of measuring VSB viscosity on-line has been designed, constructed, and tested. The viscometer will not only provide continuous on-line measurements for process control purposes, but will also determine viscosity as functions of temperature and shear rate. The latter results may be used to verify design-base information for direct coal liquefaction demonstration plants. The viscosities of Wilsonville samples of VSB and LSRC were determined as functions of shear rate and, in the case of LSRC, temperature. The VSB viscosity was found to be shear-rate sensitive, while the LSRC viscosity was temperature sensitive. A 24-h test run was unsuccessful, apparently because the check valves in the pump plugged; however, all other mechanical, electrical, and electronic equipment operated satisfactorily. The source of the plugging was thought to be degradation products, which should not cause difficulties in the pilot plant where fresh vacuum bottoms feed is always available. In summary, the results obtained in this study indicate that the viscometer system is ready to be transported to a plant such as Wilsonville and operated on-line. 7 figs., 5 tabs.

  8. Simulations of light-light scattering in quantum vacuum

    NASA Astrophysics Data System (ADS)

    Carneiro, Pedro; Grismayer, Thomas; Silva, LuíS.; Fonseca, Ricardo

    2016-10-01

    Facilities such as the Extreme Light Infrastructure (ELI) or the VULCAN 20 PW project, as well as the Petta-Watt SLAC project, coupled with the x-ray LCLSII source will allow to perform the first experiments on the probing of quantum vacuum. In our work, we developed a numerical method to self-consistently solve the nonlinear system of Maxwell's equations including quantum corrections of vacuum polarization. The robustness of our algorithm allied to the ability to integrate this tool within a particle-in-cell (PIC) method, represents an important milestone in modeling future planned experiments to prove the existence of the quantum vacuum. Such experiments aim to measure the induced ellipticity on a x-ray pulse after probing a strong optical pump due to the quantum vacuum fluctuations. We present simulation results of both the ellipticity induced and polarization rotation, using realistic laser parameters of the Petta-Watt SLAC project, and the x-ray LCLSII source, whilst taking into account all finite-size multi-dimensional effects. We show how the ellipticity induced varies as a function of the distance to the axis of the beam, proving the importance of taking into account finite-size effects. This work serves as an important tool to complement existing efforts within the community to probe the effects of the quantum vacuum, in the strong field regime, for the first time.

  9. The vacuum system for the Munich fission fragment accelerator

    NASA Astrophysics Data System (ADS)

    Maier-Komor, P.; Faestermann, T.; Krücken, R.; Nebel, F.; Winkler, S.; Groß, M.; Habs, D.; Kester, O.; Szerypo, J.; Thirolf, P. G.

    2006-05-01

    The Munich Accelerator for Fission Fragments (MAFF) is a radioactive ion beam facility which will be installed at the new research reactor FRM-II. This new reactor became critical in Spring 2004. The heart of MAFF, the target-ion source unit will be placed in the through-going beam tube of the FRM-II. This beam tube has been installed, tested and filled with helium in 2001. The cogent authorization procedures and safety levels developed for nuclear power plants are applied for this research reactor also. Therefore, MAFF also has to obey these very strict rules, because the typical 1 g load of 235U in the MAFF source creates a fission product activity of several 10 14 Bq after one reactor cycle of 52 days. All vacuum components must withstand a pressure of 6×10 5 Pa in addition to their UHV acceptability. Even dynamic gaskets must be strictly metallic, because organic compounds would not withstand the radioactive irradiation during the design lifetime of 30 years. Only dry vacuum pumps are suitable: refrigerator cryopumps for the high-vacuum part and five stages of roots pumps for roughing and regeneration.

  10. Photoelectron backscattering in vacuum phototubes

    NASA Astrophysics Data System (ADS)

    Lubsandorzhiev, B. K.; Vasiliev, R. V.; Vyatchin, Y. E.; Shaibonov, B. A. J.

    2006-11-01

    In this article we describe results of studies of a photoelectron backscattering effect in vacuum phototubes: classical photomultipliers (PMT) and hybrid phototubes (PH). Late pulses occurring in PMTs are attributed to the photoelectron backscattering and distinguished from pulses due to an anode glow effect. The late pulses are measured in a number of PMTs and HPs with various photocathode sizes covering 1 50 cm range and different types of the first dynode materials and construction designs. It is shown that the late pulses are a generic feature of all vacuum photodetectors—PMTs and PHs—and they do not deteriorate dramatically amplitude and timing responses of vacuum phototubes.

  11. Properties of vacuum-evaporated boron films

    NASA Technical Reports Server (NTRS)

    Feakes, F.

    1973-01-01

    The work on the properties of thin boron films made by vacuum evaporation of elemental boron using an electron beam as the energy source is reported. The program aimed at characterizing the properties of vacuum evaporated films. The work was directed toward those variables considered to be important in affecting the tensile strength of the boron films. In general, the thickness of the films was less than 0.002 in. The temperature of the substrate on which the boron was condensed was found to be most important. Three distinctly different forms of boron deposit were produced. Although the transition temperature was not sharply defined, at substrate temperatures of less than approximately 600 deg C the boron deposits were amorphous to X-ray. If the substrate were highly polished, the deposits were black and mirror-like. For substrates with coefficients of thermal expansion close to that of boron, the deposits were then continuous and uncracked. The studies suggest that the potential continues to exist for film-type composites to have both high strength and high modulus.

  12. DESIGN AND DEVELOPMENT OF THE SNS RING VACUUM INSTRUMENTATION AND CONTROL SYSTEMS.

    SciTech Connect

    HSEUH,H.C.; SMART,L.A.; TANG,J.Y.

    2001-06-18

    BNL is undertaking the design, construction and commissioning of the Spallation Neutron Source (SNS) accumulator ring and the beam transport lines [l]. Ultrahigh vacuum of 10{sup {minus}9} Torr is required in the accumulator ring to minimize beam-gas ionization, a contributing factor to the e-p instability observed in a few high-intensity proton storage rings. All vacuum instrumentation must be capable of local and remote operation to achieve a reliable vacuum system, especially in this extremely high intensity accelerator. The design and development of the SNS ring vacuum instrumentation and control through the Experimental Physics and Industrial Control System (EPICS) distributed real-time software tools are presented.

  13. Cartesian beams.

    PubMed

    Bandres, Miguel A; Gutiérrez-Vega, Julio C

    2007-12-01

    A new and very general beam solution of the paraxial wave equation in Cartesian coordinates is presented. We call such a field a Cartesian beam. The complex amplitude of the Cartesian beams is described by either the parabolic cylinder functions or the confluent hypergeometric functions, and the beams are characterized by three parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integration are studied in detail. Applying the general expression of the Cartesian beams, we also derive two new and meaningful beam structures that, to our knowledge, have not yet been reported in the literature. Special cases of the Cartesian beams are the standard, elegant, and generalized Hermite-Gauss beams, the cosine-Gauss beams, the Lorentz beams, and the fractional order beams.

  14. A Seemingly Simple Task: Filling a Solenoid Volume in Vacuum with Dense Plasma

    SciTech Connect

    Anders, Andre; Kauffeldt, Marina; Roy, Prabir; Oks, Efim

    2010-06-24

    Space-charge neutralization of a pulsed, high-current ion beam is required to compress and focus the beam on a target for warm dense matter physics or heavy ion fusion experiments. We described attempts to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary charge-compensating electrons. Among the options are plasma injection from four pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means and by an array of movable Langmuir probes. The plasma is produced at several cathode spots distributed azimuthally on the ring cathode. Beam neutralization and compression are accomplished, though issues of density, uniformity, and pulse-to-pulse reproducibly remain to be solved.

  15. Alumina barrier for vacuum brazing

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.

    1980-01-01

    Heating platens of vacuum-brazing press will not stick to workpiece if aluminum oxide "paper" is interposed. Paper does not disintegrate in press, will not contaminate braze alloy, and helps form smoothly contoured, regular fillet at brazed edges.

  16. Vacuum lamination of photovoltaic modules

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1982-01-01

    Vacuum lamination of terrestrial photovoltaic modules is a new high volume process requiring new equipment and newly develop materials. Equipment development, materials research, and some research in related fields and testing methods are discussed.

  17. IRIS Leaves Thermal Vacuum Chamber

    NASA Video Gallery

    This video shows the transportation of the IRIS observatory from the thermal vacuum chamber back to the clean tent for final testing and preparations for delivery to the launch site at Vandenberg A...

  18. [Endoscopic vacuum-assisted closure].

    PubMed

    Wedemeyer, J; Lankisch, T

    2013-03-01

    Anastomotic leakage in the upper and lower intestinal tract is associated with high morbidity and mortality. Within the last 10 years endoscopic treatment options have been accepted as sufficient treatment option of these surgical complications. Endoscopic vacuum assisted closure (E-VAC) is a new innovative endoscopic therapeutic option in this field. E-VAC transfers the positive effects of vacuum assisted closure (VAC) on infected cutaneous wounds to infected cavities that can only be reached endoscopically. A sponge connected to a drainage tube is endoscopically placed in the leakage and a continuous vacuum is applied. Sponge and vacuum allow removal of infected fluids and promote granulation of the leakage. This results in clean wound grounds and finally allows wound closure. Meanwhile the method was also successfully used in the treatment of necrotic pancreatitis.

  19. Dynamic vacuum analysis for APS high heat flux beamline front ends using optical ray-tracing simulation methods

    SciTech Connect

    Xu, S.; Nielsen, R.W.

    1992-01-01

    The high-power and high-flux x-ray beams produced by third generation synchrotron radiation sources such as the Advanced Photon Source (APS) can cause significantly high gas desorption rates on beamline front-end components if beam missteering occurs. The effect of this gas desorption needs to be understood for dynamic vacuum analysis. To simulate beam missteering conditions, optical ray-tracing methods have been employed. The results of the ray-tracing analysis have been entered into a system-oriented vacuum program to provide dynamic vacuum calculations for determination of pumping requirements for the beamline front-ends. The APS will provide several types of synchrotron radiation sources, for example, undulators, wigglers, and bending magnets. For the purpose of this study, the wiggler source was chosen as a worst case'' scenario due to its high photon flux, high beam power, and relatively large beam cross section.

  20. Dynamic vacuum analysis for APS high heat flux beamline front ends using optical ray-tracing simulation methods

    SciTech Connect

    Xu, S.; Nielsen, R.W.

    1992-09-01

    The high-power and high-flux x-ray beams produced by third generation synchrotron radiation sources such as the Advanced Photon Source (APS) can cause significantly high gas desorption rates on beamline front-end components if beam missteering occurs. The effect of this gas desorption needs to be understood for dynamic vacuum analysis. To simulate beam missteering conditions, optical ray-tracing methods have been employed. The results of the ray-tracing analysis have been entered into a system-oriented vacuum program to provide dynamic vacuum calculations for determination of pumping requirements for the beamline front-ends. The APS will provide several types of synchrotron radiation sources, for example, undulators, wigglers, and bending magnets. For the purpose of this study, the wiggler source was chosen as a ``worst case`` scenario due to its high photon flux, high beam power, and relatively large beam cross section.

  1. VACUUM DEPOSITION OF THIN FILMS,

    DTIC Science & Technology

    The book deals with methods of obtaining and processing thin films , methods of measuring the deposition rate and thickness of thin-film layers, and...the main fields of application of thin films . Vacuum requirements and the requirements for the composition of the residual medium in thermal...evaporation and cathode sputtering are given, and modern methods of producing and measuring vacuums and the equipment used in obtaining thin films are described. (Author)

  2. Cold cathode vacuum gauging system

    DOEpatents

    Denny, Edward C.

    2004-03-09

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

  3. Blast overpressure in rats: recreating a battlefield injury in the laboratory.

    PubMed

    Long, Joseph B; Bentley, Timothy L; Wessner, Keith A; Cerone, Carolyn; Sweeney, Sheena; Bauman, Richard A

    2009-06-01

    Blast injury to the brain is the predominant cause of neurotrauma in current military conflicts, and its etiology is largely undefined. Using a compression-driven shock tube to simulate blast effects, we assessed the physiological, neuropathological, and neurobehavioral consequences of airblast exposure, and also evaluated the effect of a Kevlar protective vest on acute mortality in rats and on the occurrence of traumatic brain injury (TBI) in those that survived. This approach provides survivable blast conditions under which TBI can be studied. Striking neuropathological changes were caused by both 126- and 147-kPa airblast exposures. The Kevlar vest, which encased the thorax and part of the abdomen, greatly reduced airblast mortality, and also ameliorated the widespread fiber degeneration that was prominent in brains of rats not protected by a vest during exposure to a 126-kPa airblast. This finding points to a significant contribution of the systemic effects of airblast to its brain injury pathophysiology. Airblast of this intensity also disrupted neurologic and neurobehavioral performance (e.g., beam walking and spatial navigation acquisition in the Morris water maze). When immediately followed by hemorrhagic hypotension, with MAP maintained at 30 mm Hg, airblast disrupted cardiocompensatory resilience, as reflected by reduced peak shed blood volume, time to peak shed blood volume, and time to death. These findings demonstrate that shock tube-generated airblast can cause TBI in rats, in part through systemic mediation, and that the resulting brain injury significantly impacts acute cardiovascular homeostatic mechanisms as well as neurobehavioral function.

  4. Efficient thermoelectric trap for metal vapours suitable for high-vacuum system

    NASA Astrophysics Data System (ADS)

    Piwinski, Mariusz; Klosowski, Lukasz; Dziczek, Darek; Chwirot, Stanislaw

    2016-09-01

    Atomic beams are widely used in various collisional experiments. Typically, cold traps are used to prevent the investigated atoms from spreading within the vacuum chamber and contaminating the system. Usually such a trap consists of a vacuum feedthrough with metal element cooled with liquid nitrogen or dry ice on the atmosphere side and a metal trap in the vacuum. Using liquid nitrogen or dry ice is relatively inconvenient due to high costs of operation and a need of periodically refilling the reservoir of the cold medium. We present a new thermoelectric cold trap composed of water-cooled vacuum feedthrough with Peltier modules placed at the high vacuum end. The present system ensures the cold trap temperature below -20°C, low enough to efficiently catch the atoms of interest. The new cold trap was characterised and compared with typical LN2 trap.

  5. Evolution of pore-fluid pressure during folding and basin contraction in overpressured reservoirs assessed by combined fracture analysis and calcite twinning paleopiezometry

    NASA Astrophysics Data System (ADS)

    Beaudoin, Nicolas; Lacombe, Olivier; Bellahsen, Nicolas; Amrouch, Khalid; Daniel, Jean-Marc

    2014-05-01

    Reconstructing the evolution of paleofluid (over)pressure in sedimentary basins during deformation is a challenging problem, especially when no hydrocarbon-bearing fluid inclusions are available to provide barometric constraints on the fluid system. This contribution reports the application to a natural case (the Bighorn Basin) of recent methodological advance to access fluid (over)pressure level prevailing in strata during sub-seismic fracture development. The fluid pressure evolution in the Mississippian-Permian Madison-Phosphoria carbonate reservoir is tentatively reconstructed from the early Sevier Layer Parallel Shortening to the Laramide folding in two basement-cored folds: the Sheep Mountain Anticline and the Rattlesnake Mountain Anticline, located on both edges of the Bighorn Basin. This reconstruction is based on a combination of stress inversion of fault slip data, calcite twins paleopiezometry and rock mechanics. Results point out that supra-hydrostatic pressure values prevail in the carbonate reservoir during most of its whole Sevier-Laramide history, and a coeval evolution between fluid overpressure and differential stress build-up is also emphasized. In each fold, a maximum value of 30-35 MPa for overpressure (i.e. above hydrostatic value) is recorded, just before Laramide folding, while minimum values of 0 MPa or 7 MPa are recorded during Sevier foreland flexure/forebulge and Laramide folding, respectively. After normalization to the same depth for both folds of differential stress magnitudes obtained from calcite twins paleopiezometry, the reconstructed values for the two folds can be compared and this comparison provides an image of the evolution fluid pressure levels at the basin scale. Until folding, the evolution of the fluid overpressure during deformation can be interpreted as reflecting large-scale fluid migrations in a laterally connected reservoir. The drop of fluid overpressure recorded in both folds during folding illustrates the

  6. Can we infer the magma overpressure threshold before an eruption? Insights from ground deformation time series and numerical modeling of reservoir failure.

    NASA Astrophysics Data System (ADS)

    Albino, F.; Gregg, P. M.; Amelug, F.

    2015-12-01

    Overpressure within a magma chamber is a key parameter to understanding the onset of an eruption. Recent investigations indicate that surface inflation at a volcanic edifice does not always precede eruption (Chaussard and Amelung, 2012; Biggs et al., 2014), suggesting that the overpressure threshold may differ between volcanoes. To understand the failure conditions of a magma reservoir, mechanical models were developed to quantify the range of overpressure affordable in a reservoir for a given situation. Even if the choice of the failure criterion is still debated, most investigators agree that the overpressure required to fail the magma reservoir is at first order a function of the crustal stress field and the shape of the magma reservoir. Radar interferometry (InSAR) provides a large dataset of ground deformation worldwide, but many of these InSAR studies continue to use point or dislocation sources (Mogi, Okada) to explain deformation on volcanoes. Even if these simple solutions often fit the data and estimate the depth and the volume change of the source of deformation, key parameters such as the magma overpressure or the mechanical properties of the rocks cannot be derived. We use mechanical numerical models of reservoir failure combined with ground deformation data. It has been observed that volume change before an eruption can easily range one or two order of magnitude from 1-100x106 m3. The first goal of this study is to understand which parameter(s) control the critical volume changes just before the failure of the reservoir. First, a parametric study is performed to quantify the effect of the geometry of the reservoir (radius, depth), the local stress (compressive/extensive) and even the crust rheology (elastic/viscoelastic). We then compare modeling results with several active volcanoes where long time series of volume change are available: Okmok and Westdahl in Alaska, Sinabung and Agung in Indonesia and Galapagos. For each case, the maximum

  7. Atomically Thin Graphene Windows That Enable High Contrast Electron Microscopy without a Specimen Vacuum Chamber.

    PubMed

    Han, Yimo; Nguyen, Kayla X; Ogawa, Yui; Park, Jiwoong; Muller, David A

    2016-12-14

    Scanning electron microscopes (SEMs) require a high vacuum environment to generate and shape an electron beam for imaging; however, the vacuum conditions greatly limit the nature of specimens that can be examined. From a purely scattering physics perspective, it is not necessary to place the specimen inside the vacuum chamber-the mean free paths (MFPs) for electron scattering in air at typical SEM beam voltages are 50-100 μm. This is the idea behind the airSEM, which removes the specimen vacuum chamber from the SEM and places the sample in air. The thickness of the gas layer is less than a MFP from an electron-transparent window to preserve the shape and resolution of the incident beam, resulting in comparable imaging quality to an all-vacuum SEM. Present silicon nitride windows scatter far more strongly than the air gap and are currently the contrast and resolution limiting factor in the airSEM. Graphene windows have been used previously to wrap or seal samples in vacuum for imaging. Here we demonstrate the use of a robust bilayer graphene window for sealing the electron optics from the room environment, providing an electron transparent window with only a 2% drop in contrast. There is a 5-fold-increase in signal/noise ratio for imaging compared to multi-MFP-thick silicon nitride windows, enabling high contrast in backscattered, transmission, and surface imaging modes for the new airSEM geometry.

  8. Influence of fluid overpressure on sliding with or without frontal buttress. Insights from analytical and experimental modeling

    NASA Astrophysics Data System (ADS)

    Lacoste, A.; Vendeville, B.; Mourgues, R.; Loncke, L.

    2009-12-01

    Hydrocarbon cracking can generate gases that migrate upward and may be trapped beneath low-permeability strata. The resulting fluid overpressure reduces shear strength, allowing gravitational sliding of the overlying cover. The driving force is the slope-parallel component of the weight of the cover, whereas the resisting forces are the friction at the base of the cover and the buttressing resistance to shortening downslope. Typically, a slide is bounded by normal faults upslope and thrusts downslope. But, sometimes, the slide is bounded downslope by a creek incision, and no compressional structures are found. We show how these two types of slides markedly differ in terms of mechanics, geometry, and kinematics using both analytical and experimental models. Mourgues et al. (2009) proposed an analytical model for gravity sliding of a laterally continuous sedimentary pile overlying an overpressured horizon. There, sliding can occur only if the driving force can overcome the buttressing resistance downslope, i.e., if the slide has a minimum required length, which depends on the thickness and rheological properties of the cover, and fluid pressure. The predicted length of the slide decreases with increasing pore pressure and decreasing cover thickness (Fig.1A). We ran the same calculation for a set up in which the base of the slope is incised, hence there is no downslope buttress. Unlike the first set up, the sliding sheet length increases with increasing fluid pressure (Fig.1B). We also tested the influence of varying slope angles, cover thicknesses and permeabilities of the décollement layer. The fluid pressure required to trigger sliding decreases where the basal slope and the cover thickness increase. Changes in décollement permeability have only a minor influence. We undertook a series of analogue experiments to check the evolution predicted by the analytical models. Fluids were simulated by compressed air applied at the base of models made of sand and low

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

  10. Bragg scattering of light in vacuum structured by strong periodic fields.

    PubMed

    Kryuchkyan, Gagik Yu; Hatsagortsyan, Karen Z

    2011-07-29

    Elastic scattering of laser radiation due to vacuum polarization by spatially modulated strong electromagnetic fields is considered. The Bragg interference arising at a specific impinging direction of the probe wave concentrates the scattered light in specular directions. The interference maxima are enhanced with respect to the usual vacuum polarization effect proportional to the square of the number of modulation periods within the interaction region. The Bragg scattering can be employed to detect the vacuum polarization effect in a setup of multiple crossed superstrong laser beams with parameters envisaged in the future Extreme Light Infrastructure.

  11. Vacuum-Gauge Connection For Shipping Container

    NASA Technical Reports Server (NTRS)

    Henry, Robert H.

    1990-01-01

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

  12. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y. Simon

    1991-01-01

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used.

  13. Oxygen ion-beam microlithography

    DOEpatents

    Tsuo, Y.S.

    1991-08-20

    A method of providing and developing a resist on a substrate for constructing integrated circuit (IC) chips includes the following steps: of depositing a thin film of amorphous silicon or hydrogenated amorphous silicon on the substrate and exposing portions of the amorphous silicon to low-energy oxygen ion beams to oxidize the amorphous silicon at those selected portions. The nonoxidized portions are then removed by etching with RF-excited hydrogen plasma. Components of the IC chip can then be constructed through the removed portions of the resist. The entire process can be performed in an in-line vacuum production system having several vacuum chambers. Nitrogen or carbon ion beams can also be used. 5 figures.

  14. Multi-beam linear accelerator EVT

    NASA Astrophysics Data System (ADS)

    Teryaev, Vladimir E.; Kazakov, Sergey Yu.; Hirshfield, Jay L.

    2016-09-01

    A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

  15. Recycler short kicker beam impedance

    SciTech Connect

    Crisp, Jim; Fellenz, Brian; /Fermilab

    2009-07-01

    Measured longitudinal and calculated transverse beam impedance is presented for the short kicker magnets being installed in the Fermilab Recycler. Fermi drawing number ME-457159. The longitudinal impedance was measured with a stretched wire and the Panofsky equation was used to estimate the transverse impedance. The impedance of 3319 meters (the Recycler circumference) of stainless vacuum pipe is provided for comparison. Although measurements where done to 3GHz, impedance was negligible above 30MHz. The beam power lost to the kicker impedance is shown for a range of bunch lengths. The measurements are for one kicker assuming a rotation frequency of 90KHz. Seven of these kickers are being installed.

  16. Rovibrationally selected ion-molecule collision study using the molecular beam vacuum ultraviolet laser pulsed field ionization-photoion method: Charge transfer reaction of N{sub 2}{sup +}(X {sup 2}{Sigma}{sub g}{sup +}; v{sup +}= 0-2; N{sup +}= 0-9) + Ar

    SciTech Connect

    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{sub 2}{sup +}(v{sup +}, N{sup +}) + 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{sub 2}{sup +}(X {sup 2}{Sigma}{sub g}{sup +}, v{sup +}= 0-2, N{sup +}= 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{sub 2}{sup +} PFI-PI beam can be formed with a laboratory kinetic energy resolution of {Delta}E{sub lab}={+-} 50 meV. As a result, the total cross section measurement can be conducted at center-of-mass kinetic energies (E{sub cm}'s) down to thermal energies. Absolute total rovibrationally selected cross sections {sigma}(v{sup +}= 0-2, N{sup +}= 0-9) for the N{sub 2}{sup +}(X {sup 2}{Sigma}{sub g}{sup +}; v{sup +}= 0-2, N{sup +}= 0-9) + Ar CT reaction have been measured in the E{sub cm} range of 0.04-10.0 eV, revealing strong vibrational enhancements and E{sub cm}-dependencies of {sigma}(v{sup +}= 0-2, N{sup +}= 0-9). The thermochemical threshold at E{sub cm}= 0.179 eV for the formation of Ar{sup +} from N{sub 2}{sup +}(X; v{sup +}= 0, N{sup +}) + Ar was observed by the measured {sigma}(v{sup +}= 0), confirming the narrow {Delta}E{sub cm} spread achieved in

  17. Vacuum Packaging for Microelectromechanical Systems (MEMS)

    DTIC Science & Technology

    2002-10-01

    The Vacuum Packaging for MEMS Program focused on the development of an integrated set of packaging technologies which in totality provide a low cost...high volume product-neutral vacuum packaging capability which addresses all MEMS vacuum packaging requirements. The program balanced the need for...near term component and wafer-level vacuum packaging with the development of advanced high density wafer-level packaging solutions. Three vacuum

  18. Probability distribution of the vacuum energy density

    SciTech Connect

    Duplancic, Goran; Stefancic, Hrvoje; Glavan, Drazen

    2010-12-15

    As the vacuum state of a quantum field is not an eigenstate of the Hamiltonian density, the vacuum energy density can be represented as a random variable. We present an analytical calculation of the probability distribution of the vacuum energy density for real and complex massless scalar fields in Minkowski space. The obtained probability distributions are broad and the vacuum expectation value of the Hamiltonian density is not fully representative of the vacuum energy density.

  19. Test of Thermal Transport Models through Dynamic Overpressure Stabilization of Ablation-Front Perturbation Growth in Laser-Driven CH Foils

    SciTech Connect

    Gotchev, O.V.; Goncharov, V.N.; Knauer, J.P.; Boehly, T.R.; Collins, T.J.B.; Epstein, R.; Jaanimagi, P.A.; Meyerhofer, D.D.

    2006-03-24

    Heat-flow-induced dynamic overpressure at the perturbed ablation front of an ICF target can stabilize the ablative Richtmyer/Meshkov-like instability and mitigate the subsequent ablative Rayleigh/Taylor (RT) instability. A series of experiments was performed on the OMEGA laser to quantify the dynamic overpressure stabilization during the shock transit. Analysis of the experimental data using hydrocode simulations shows that the observed oscillatory evolution of the ablation-front perturbations depends on Dc, the size of the thermal conduction zone, and the fluid velocity in the blowoff region Vbl that are sensitive to the thermal transport model used. We show that the simulations match the experiment well when the time dependence of the heat-flux inhibition is taken into account using a recently developed nonlocal heat transport model.

  20. The Study of Advanced Accelerator Physics Research at UCLA Using the ATF at BNL: Vacuum Acceleration by Laser of Free Electrons

    SciTech Connect

    Cline, David B.

    2016-09-07

    An experiment was designed and data were taken to demonstrate that a tightly focused laser on vacuum can accelerate an electron beam in free space. The experiment was proof-of-principle and showed a clear effect for the laser beam off and on. The size of the effect was about 20% and was consistent over 30 laser and beam shots.

  1. Operation Hardtack. Project 3. 2. Response of earth-confined flexible-arch structures in high-overpressure regions

    SciTech Connect

    LeDoux, J.C.; Rush, P.J.

    1985-09-01

    The purpose of this project was to determine structural responses and failure criteria of earth-confined corrugated-steel flexible arches subjected to high overpressure blast loading from nuclear detonations. A flexible arch is considered as an arch structure whose ultimate supporting capacity is dependent upon confinement within a surrounding earth configuration. A collateral objective was to determine the radiation-shielding effectiveness of such structures with a minimum cover of five feet of coral sand. Because the soil and ground-water conditions at Eniwetok did not permit the placing of the steel arches below natural-grade level, the structures were confined within massive non-drag sensitive earthwork configurations of coral sand. Empirical determinations were made of the responses of (1) three earth-confined prefabricated corrugated-steel flexible arches when subjected to relatively long-duration blast loadings from a megaton range detonation; and (2) one similar earth-confined flexible-arch when subjected to relatively short-duration blast loadings from a kiloton-range detonation.

  2. Effects of Exposure to Blast Overpressure on Intracranial Pressure and Blood-Brain Barrier Permeability in a Rat Model

    PubMed Central

    Kawoos, Usmah; Gu, Ming; Lankasky, Jason; McCarron, Richard M.; Chavko, Mikulas

    2016-01-01

    Exposure to blast overpressure (BOP) activates a cascade of pathological processes including changes in intracranial pressure (ICP) and blood-brain barrier (BBB) permeability resulting in traumatic brain injury (TBI). In this study the effect of single and multiple exposures at two intensities of BOP on changes in ICP and BBB permeability in Sprague-Dawley rats was evaluated. Animals were exposed to a single or three repetitive (separated by 0.5 h) BOPs at 72 kPa or 110 kPa. ICP was monitored continuously via telemetry for 6 days after exposure to BOP. The alteration in the permeability of BBB was determined by extravasation of Evans Blue (EB) into brain parenchyma. A significant increase in ICP was observed in all groups except the single 72 kPa BOP group. At the same time a marked increase in BBB permeability was also seen in various parts of the brain. The extent of ICP increase as well as BBB permeability change was dependent on intensity and frequency of blast. PMID:27907158

  3. Deposition of dielectric films on silicon using a fore-vacuum plasma electron source.

    PubMed

    Zolotukhin, D B; Oks, E M; Tyunkov, A V; Yushkov, Yu G

    2016-06-01

    We describe an experiment on the use of a fore-vacuum-pressure, plasma-cathode, electron beam source with current up to 100 mA and beam energy up to 15 keV for deposition of Mg and Al oxide films on Si substrates in an oxygen atmosphere at a pressure of 10 Pa. The metals (Al and Mg) were evaporated and ionized using the electron beam with the formation of a gas-metal beam-plasma. The plasma was deposited on the surface of Si substrates. The elemental composition of the deposited films was analyzed.

  4. Orbital-angular-momentum transfer to optically levitated microparticles in vacuum

    NASA Astrophysics Data System (ADS)

    Mazilu, Michael; Arita, Yoshihiko; Vettenburg, Tom; Auñón, Juan M.; Wright, Ewan M.; Dholakia, Kishan

    2016-11-01

    We demonstrate the transfer of orbital angular momentum to an optically levitated microparticle in vacuum. The microparticle is placed within a Laguerre-Gaussian beam and orbits the annular beam profile with increasing angular velocity as the air drag coefficient is reduced. We explore the particle dynamics as a function of the topological charge of the levitating beam. Our results reveal that there is a fundamental limit to the orbital angular momentum that may be transferred to a trapped particle, dependent upon the beam parameters and inertial forces present.

  5. Evaluation of Novel Polyunsaturated Fatty Acid Derived Lipid Mediators of Inflammation to Ameliorate the Deleterious Effects of Blast Overpressure on Eye and Brain Visual Processing Centers in Rats

    DTIC Science & Technology

    2013-10-01

    simulated blast overpressure waves the cellular, neuronal signaling, behavioral pathology of injuries to the eyes - specifically retina - and brain ...adult rat model of blast wave exposure, we rigorously characterized the cellular and functional damage to the eyes (retinas) and brain visual...strong relationship between the retina and brain optic tract cell damage (r = 0.8). Overall, our findings demonstrate that blast wave exposure leads

  6. Response of Basic Structural Elements and B-52 Structural Components to Simulated Nuclear Overpressure. Volume I-Program Description and Results (Basic Structural Elements)

    DTIC Science & Technology

    1979-09-30

    overpressure pulse, were generated by ignit- iog PETN primacord and composition 4 explosive charges. The explosive was positioned in the centerline of the...L r- r-t(HONIfS NH3 I-O NI ) NI~flhJS 107 0( V)- 1 T-4 < > ui CY) < r C)- uj (D 0 ~u J4I C)i C)C CDD LOO0C 1i ( HN /MN-OO IU 1081 TABLE 11 STATIC LOAD

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

    NASA Technical Reports Server (NTRS)

    Huber, W. K.

    1986-01-01

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

  8. Vacuum-assisted cesarean section

    PubMed Central

    McQuivey, Ross W; Block, Jon E

    2017-01-01

    There has been a dramatic rise in the frequency of cesarean sections, surpassing 30% of all deliveries in the US. This upsurge, coupled with a decreasing willingness to allow vaginal birth after cesarean section, has resulted in an expansion of the use of vacuum assistance to safely extract the fetal head. By avoiding the use of a delivering hand or forceps blade, the volume being delivered through the uterine incision can be decreased when the vacuum is used properly. Reducing uterine extensions with their associated complications (eg, excessive blood loss) in difficult cases is also a theoretical advantage of vacuum delivery. Maternal discomfort related to excessive fundal pressure may also be lessened. To minimize the risk of neonatal morbidity, proper cup placement over the “flexion point” remains essential to maintain vacuum integrity and reduce the chance of inadvertent detachment and uterine extensions. Based on the published literature and pragmatic clinical experience, utilization of the vacuum device is a safe and effective technique to assist delivery during cesarean section. PMID:28331371

  9. VACUUM TRAP AND VALVE COMBINATION

    DOEpatents

    Milleron, N.; Levenson, L.

    1963-02-19

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

  10. Suprathermal electrons produced by beam-plasma-discharge

    NASA Technical Reports Server (NTRS)

    Sharp, W. E.

    1982-01-01

    Experiments conducted with a low energy plasma lens, HARP, in the electron beam of the large vacuum chamber at Johnson Space Center indicate that an enhanced population of 50 to 300 volt electrons appear when the beam goes into the Beam-Plasma Discharge (BPD) mode. Below the BPD instability the electron distribution appears to be characterized as non-energized single particle scattering and energy loss. At 100 cm from the beam core in the BPD mode the fluxes parallel to the beam are reduced by a factor of 20 with respect to the fluxes at 25 cm. Some evidence for isotropy near the beam core is presented.

  11. In vacuum undulator task force report

    SciTech Connect

    Hastings, J.B.; Kao, C.C.; Stefan, P.

    1998-06-01

    Historically the NSLS has been active in R&D for state-of-the-art electron beams, photon beams and x-ray optics. One of the available straight sections has therefore been dedicated to insertion device R&D. Over the past five to seven years a program aimed at exploiting the very small vertical {beta} function in the straight sections has yielded first a prototype small gap undulator (PSGU) and then an in-vacuum undulator (IVUN). The IVUN sources attain a brightness similar to the existing hybrid wigglers in X21 and X25. They radiate significantly lower total power than the wigglers but produce higher power densities. They provide undulator rather than wiggler spectra. Because of the small gaps and small periods there is not much tunability in these devices and they will have to be purpose-built for a specific scientific program. The original IVUN parameters were chosen for in-elastic x-ray scattering, similar to the scientific program on X21. This put the fundamental at 4.6 keV and the third harmonic at 13.8 keV. The question that this new possible insertion device poses is what science programs can best take advantage of this new insertion device source? To answer this, a task force was formed by M. Hart, NSLS Department Chair and charged with identifying viable scientific programs that could seek outside funding to construct IVUN beamlines. The task force concentrated on experimental programs that are presently being pursued on new insertion devices worldwide. For example, x-ray photon correlation spectroscopy, which takes advantage of the large coherent flux from undulator sources, was considered. However, this program was not considered as the highest priority. The general area of protein crystallography, however, is ideal for the IVUN source. The unique electron beam optics that makes the IVUN possible in the first place also makes the IVUN ideal as a source for microdiffraction.

  12. Explosion impacts during transport of hazardous cargo: GIS-based characterization of overpressure impacts and delineation of flammable zones for ammonia.

    PubMed

    Inanloo, Bahareh; Tansel, Berrin

    2015-06-01

    The aim of this research was to investigate accidental releases of ammonia followed by an en-route incident in an attempt to further predict the consequences of hazardous cargo accidents. The air dispersion model Areal Locations of Hazardous Atmospheres (ALOHA) was employed to track the probable outcomes of a hazardous material release of a tanker truck under different explosion scenarios. The significance of identification of the flammable zones was taken into consideration; in case the flammable vapor causes an explosion. The impacted areas and the severity of the probable destructions were evaluated for an explosion by considering the overpressure waves. ALOHA in conjunction with ArcGIS was used to delineate the flammable and overpressure impact zones for different scenarios. Based on the results, flammable fumes were formed in oval shapes having a chief axis along the wind direction at the time of release. The expansions of the impact areas under the overpressure value which can lead to property damage for 2 and 20 tons releases, under very stable and unstable atmospheric conditions were estimated to be around 1708, 1206; 3742, 3527 feet, respectively, toward the wind direction. A sensitivity analysis was done to assess the significance of wind speed on the impact zones. The insight provided by this study can be utilized by decision makers in transportation of hazardous materials as a guide for possible rerouting, rescheduling, or limiting the quantity of hazardous cargo to reduce the possible impacts after hazardous cargo accidents during transport.

  13. Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

    PubMed Central

    Ishigaki, Yasuhito; Nakamura, Yuka; Oikawa, Yosaburo; Yano, Yasuhiro; Kuwabata, Susumu; Nakagawa, Hideaki; Tomosugi, Naohisa; Takegami, Tsutomu

    2012-01-01

    Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition. PMID:22431980

  14. Silicon Holder For Molecular-Beam Epitaxy

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.; Grunthaner, Paula J.; Grunthaner, Frank J.

    1993-01-01

    Simple assembly of silicon wafers holds silicon-based charge-coupled device (CCD) during postprocessing in which silicon deposited by molecular-beam epitaxy. Attains temperatures similar to CCD, so hotspots suppressed. Coefficients of thermal expansion of holder and CCD equal, so thermal stresses caused by differential thermal expansion and contraction do not develop. Holder readily fabricated, by standard silicon processing techniques, to accommodate various CCD geometries. Silicon does not contaminate CCD or molecular-beam-epitaxy vacuum chamber.

  15. Gravity-Induced Vacuum Dominance

    SciTech Connect

    Lima, William C. C.; Vanzella, Daniel A. T.

    2010-04-23

    It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications.

  16. Gravity-induced vacuum dominance.

    PubMed

    Lima, William C C; Vanzella, Daniel A T

    2010-04-23

    It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, subdominant contributions. This view seemed to be endorsed by the seminal results obtained over the last decades in the context of renormalization of quantum fields in curved spacetimes. Here, however, we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background spacetime, to become dominant over any classical energy-density component. By estimating the time scale for the vacuum energy density to become dominant, and therefore for backreaction on the background spacetime to become important, we argue that this (infrared) vacuum dominance may bear unexpected astrophysical and cosmological implications.

  17. Microscale Digital Vacuum Electronic Gates

    NASA Technical Reports Server (NTRS)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  18. D-Zero Vacuum System

    SciTech Connect

    Wintercorn, S.J.; /Fermilab

    1986-04-07

    The system pumping speed was calculated by taking the reciprocal of the sum of the reciprocal pump speed and the reciprocal line conductances. The conductances of the pipe were calculated from the following formulas taken from the Varian vacuum manual. This report updates the original to reflect the pumping curves and basic vacuum system characteristics for the purchased components and installed piping of the D-Zero vacuum system. The system consists of two Edward's E2M275 two stage mechanical pumps, a Leybold-Heraeus WSU2000 Blower and three Varian 4' diffusion pumps (one for each cryostat). Individual pump and system pumping speed curves and a diagram of the system is included.

  19. Vacuum Arc Ion Sources: Recent Developments and Applications

    SciTech Connect

    Brown, Ian; Oks, Efim

    2005-05-01

    The vacuum arc ion source has evolved over the past twenty years into a standard laboratory tool for the production of high current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. The primary application of this kind of source has evolved to be ion implantation for material surface modification. Another important use is for injection of high current beams of heavy metal ions into the front ends of particle accelerators, and much excellent work has been carried out in recent years in optimizing the source for reliable accelerator application. The source also provides a valuable tool for the investigation of the fundamental plasma physics of vacuum arc plasma discharges. As the use of the source has grown and diversified, at the same time the ion source performance and operational characteristics have been improved in a variety of different ways also. Here we review the growth and status of vacuum arc ion sources around the world, and summarize some of the applications for which the sources have been used.

  20. Vacuum deposited polymer/metal films for optical applications

    NASA Astrophysics Data System (ADS)

    Affinito, J. D.; Martin, P. M.; Gross, M. E.; Coronado, C.; Greenwell, E.

    1995-04-01

    Vacuum deposited Polymer/Silver/Polymer reflectors and Tantalum/Polymer/Aluminum Fabry-Perot interference filters were fabricated in a vacuun web coating operation on polyester substrates with a new, high speed deposition process. Reflectivities were measured in the wavelength range from 0.3 to 0.8(mu)m. This new vacuum processing technique has been shown to be capable of deposition line speeds in excess of 500 linear meters/minute. Central to this technique is a new position 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. Also, vacuum deposited, index matched, polymer/CaF(sub 2) composites were fabricated from monomer slurries that were subsequently cured with LTV light. This second technique is called the Liquid Multi-Layer (or LML) process. Each of these polymer processes is compatible with each other and with conventional vacuum deposition processes such as sputtering or evaporation.

  1. Silicon crystal growth in vacuum

    NASA Technical Reports Server (NTRS)

    Khattak, C. P.; Schmid, F.

    1982-01-01

    The most developed process for silicon crystal growth is the Czochralski (CZ) method which was in production for over two decades. In an effort to reduce cost of single crystal silicon for photovoltaic applications, a directional solidification technique, Heat Exchanger Method (HEM), was adapted. Materials used in HEM and CZ furnaces are quite similar (heaters, crucibles, insulation, etc.). To eliminate the cost of high purity argon, it was intended to use vacuum operation in HEM. Two of the major problems encountered in vacuum processing of silicon are crucible decomposition and silicon carbide formation in the melt.

  2. Vacuum Plasma Spraying Replaces Electrodeposition

    NASA Technical Reports Server (NTRS)

    Holmes, Richard R.; Power, Chris; Burns, David H.; Daniel, Ron; Mckechnie, Timothy N.

    1992-01-01

    Vacuum plasma spraying used to fabricate large parts with complicated contours and inner structures, without uninspectable welds. Reduces time, and expense of fabrication. Wall of combustion chamber built up inside of outer nickel-alloy jacket by plasma spraying. Particles of metal sprayed partially melted in plasma gun and thrown at supersonic speed toward deposition surface. Vacuum plasma-spray produces stronger bond between the grooves and covering layer completing channels and wall of combustion chamber. In tests, bond withstood pressure of 20 kpsi, three times allowable limit by old method.

  3. Vacuum Cleaner Fan Being Improved

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.

    1997-01-01

    As part of the technology utilization program at the NASA Lewis Research Center, efforts are underway to transfer aerospace technologies to new areas of practical application. One such effort involves using advanced computational fluid dynamics (CFD) codes for turbomachinery to analyze the internal fluid dynamics of low-speed fans and blowers. This year, the Kirby Company in Cleveland, Ohio, approached NASA with a request for technologies that could help them improve their vacuum cleaners. Of particular interest to Kirby is the high-frequency blade-passing noise generation of their vacuum cleaner fan at low airflow rates.

  4. Method for vacuum fusion bonding

    DOEpatents

    Ackler, Harold D.; Swierkowski, Stefan P.; Tarte, Lisa A.; Hicks, Randall K.

    2001-01-01

    An improved vacuum fusion bonding structure and process for aligned bonding of large area glass plates, patterned with microchannels and access holes and slots, for elevated glass fusion temperatures. Vacuum pumpout of all components is through the bottom platform which yields an untouched, defect free top surface which greatly improves optical access through this smooth surface. Also, a completely non-adherent interlayer, such as graphite, with alignment and location features is located between the main steel platform and the glass plate pair, which makes large improvements in quality, yield, and ease of use, and enables aligned bonding of very large glass structures.

  5. Development of a focused ion beam micromachining system

    SciTech Connect

    Pellerin, J.G.; Griffis, D.; Russell, P.E.

    1988-12-01

    Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

  6. Dispensing targets for ion beam particle generators

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1974-01-01

    A target for dispensing high energy protons or neutrons or ionized atoms or ionized molecules is provided which comprises a container for the target gas, which is at atmospheric or higher pressure. The container material can release the target gas in the spot where the container is heated above a predetermined temperature by the impact of an ion beam where protons or neutrons are desired, or by electrons where ionized atoms or molecules are desired. On the outside of the container, except for the region where the beam is to impact, there is deposited a layer of a metal which is imperious to gaseous diffusion. A further protective coating of a material is placed over the layer of metal, except at the region of the ion impact area in order to adsorb any unreacted gas in the vacuum in which the target is placed, to thereby prevent reduction of the high vacuum, as well as contamination of the interior of the vacuum chamber.

  7. Focused ion beam micromilling 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.

  8. Focused ion beam micromilling and articles therefrom

    DOEpatents

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

    1998-06-30

    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.

  9. Space-Charge Modulation in Vacuum Microdiodes at THz Frequencies

    SciTech Connect

    Pedersen, Andreas; Manolescu, Andrei; Valfells, Agust

    2010-04-30

    We investigate the dynamics of a space-charge limited, photoinjected, electron beam in a microscopic vacuum diode. Because of the small nature of the system it is possible to conduct high-resolution simulations where the number of simulated particles is equal to the number of electrons within the system. In a series of simulations of molecular dynamics type, where electrons are treated as point charges, we address and analyze space-charge effects in a micrometer-scale vacuum diode. We have been able to reproduce breakup of a single pulse injected with a current density beyond the Child-Langmuir limit, and we find that continuous injection of current into the diode gap results in a well-defined train of electron bunches corresponding to THz frequency. A simple analytical explanation of this behavior is given.

  10. Solar heated vacuum pyrolysis of lunar soil

    NASA Astrophysics Data System (ADS)

    Sauerborn, M.; Neumann, A.; Seboldt, W.; Diekmann, B.

    The goal of the project is the thermal reduction of samples of lunar regolith simulant as a possible technique for producing oxygen by pyrolysis on a lunar base. The extraterrestrial production of oxygen is a key technology for a lunar base or manned missions to near-Earth asteroids or Mars. The solar heated vacuum pyrolysis has some important advantages, because it is based upon the realities of the lunar environment. As a tool for investigating the basic reactions and the technology the DLR High Flux Solar Furnace was used. This facility is operated since 1994 in Cologne. It delivers concentrated solar radiation up to a peak flux of 5 MW/m2. This power can be used to cause thermal or photochemical effects in irradiated materials. For the astrophysical and mineralogical applications discussed here, a vacuum chamber with a solar-adapted design and new instrumentation was developed. The pyrolysis experiments were conducted under high vacuum. Using the concentrated beam of the solar furnace as heat source, the lunar soil simulant samples achieved liquid phase in 10 - 20 seconds and reached temperatures between 1500 to 1900 K, were the relevant processes took place. The heating phase was followed by a controlled cooling. The partial pressure of oxygen and several other constituents in the vapour phase was measured with a differentially pumped quadrupole mass spectrometer. The temperatures of the samples were measured by an IR camera with a special optical system. Baseline experiments with different reference metal oxides like SiO2, CaO, and ZnO were made to verify the apparatus and investigate background contamination. The data of the five experiments with regolith showed typical features and a similar behaviour of gas partial pressure depending on temperature level, with an increase of oxygen during the strongest irradiation. The detected oxygen originates from thermal decomposition of the mineral sample and caused a large numbers of gas bubbles inside the melt

  11. Performance of an over-pressure processed Bi-2223/Ag/SUS tape and a small layer-winding coil

    NASA Astrophysics Data System (ADS)

    Kitaguchi, Hitoshi; Takahashi, Ken-ichiro; Kumakura, Hiroaki; Hayashi, Toshihiro; Fujino, Kousou; Ayai, Naoki; Sato, Ken-ichi

    2009-04-01

    We have successfully demonstrated the utility and potential of Bi-2223/Ag tapes fabricated by a CT-OP (controlled-overpressure) process. In this paper, we report the Ic-B-T performance of a short tape with stainless steel lamination and energizing-test results of a small layer-winding coil in an external magnetic field ranging from 0 to 12 T and at temperatures ranging from 4.2 to 90 K. The coil is a solenoid layer-winding of a 135 m piece of Bi-2223/Ag tape with stainless steel lamination on both sides. The dimensions of the conductor are 2.7 mm in width and 0.25 mm in thickness, including a 0.02 mm thick stainless steel lamination on both sides. A short sample cut from the same tape has critical currents exceeding 76 A, 307 A and 438 A at 77 K, 30 K and 4.2 K, respectively, in self-field. The winding was performed using a 'react & wind' technique and the resultant coil had 597 turns and dimensions of 65 mm (inner diameter), 83 mm (outer diameter) and 60 mm (winding height). In 12 T, 4.2 K, the coil-Ic is 191 A, which adds 1.42 T to the external field. In the present coil, the coil-Ic is controlled by the field component in the coil's radial direction generated by the coil itself. The Ic values of the coil agree very well with those estimated from the short sample's performance and field distribution. The results indicate that the homogeneity of the Bi-2223 conductor is very good throughout its whole 135 m length.

  12. Primary blast causes mild, moderate, severe and lethal TBI with increasing blast overpressures: Experimental rat injury model

    PubMed Central

    Mishra, Vikas; Skotak, Maciej; Schuetz, Heather; Heller, Abi; Haorah, James; Chandra, Namas

    2016-01-01

    Injury severity in blast induced Traumatic Brain Injury (bTBI) increases with blast overpressure (BOP) and impulse in dose-dependent manner. Pure primary blast waves were simulated in compressed gas shock-tubes in discrete increments. Present work demonstrates 24 hour survival of rats in 0–450 kPa (0–800 Pa∙s impulse) range at 10 discrete levels (60, 100, 130, 160, 190, 230, 250, 290, 350 and 420 kPa) and determines the mortality rate as a non-linear function of BOP. Using logistic regression model, predicted mortality rate (PMR) function was calculated, and used to establish TBI severities. We determined a BOP of 145 kPa as upper mild TBI threshold (5% PMR). Also we determined 146–220 kPa and 221–290 kPa levels as moderate and severe TBI based on 35%, and 70% PMR, respectively, while BOP above 290 kPa is lethal. Since there are no standards for animal bTBI injury severity, these thresholds need further refinements using histopathology, immunohistochemistry and behavior. Further, we specifically investigated mild TBI range (0–145 kPa) using physiological (heart rate), pathological (lung injury), immuno-histochemical (oxidative/nitrosative and blood-brain barrier markers) as well as blood borne biomarkers. With these additional data, we conclude that mild bTBI occurs in rats when the BOP is in the range of 85–145 kPa. PMID:27270403

  13. Primary blast causes mild, moderate, severe and lethal TBI with increasing blast overpressures: Experimental rat injury model

    NASA Astrophysics Data System (ADS)

    Mishra, Vikas; Skotak, Maciej; Schuetz, Heather; Heller, Abi; Haorah, James; Chandra, Namas

    2016-06-01

    Injury severity in blast induced Traumatic Brain Injury (bTBI) increases with blast overpressure (BOP) and impulse in dose-dependent manner. Pure primary blast waves were simulated in compressed gas shock-tubes in discrete increments. Present work demonstrates 24 hour survival of rats in 0–450 kPa (0–800 Pa•s impulse) range at 10 discrete levels (60, 100, 130, 160, 190, 230, 250, 290, 350 and 420 kPa) and determines the mortality rate as a non-linear function of BOP. Using logistic regression model, predicted mortality rate (PMR) function was calculated, and used to establish TBI severities. We determined a BOP of 145 kPa as upper mild TBI threshold (5% PMR). Also we determined 146–220 kPa and 221–290 kPa levels as moderate and severe TBI based on 35%, and 70% PMR, respectively, while BOP above 290 kPa is lethal. Since there are no standards for animal bTBI injury severity, these thresholds need further refinements using histopathology, immunohistochemistry and behavior. Further, we specifically investigated mild TBI range (0–145 kPa) using physiological (heart rate), pathological (lung injury), immuno-histochemical (oxidative/nitrosative and blood-brain barrier markers) as well as blood borne biomarkers. With these additional data, we conclude that mild bTBI occurs in rats when the BOP is in the range of 85–145 kPa.

  14. Vacuum-jacketed line spacer

    NASA Technical Reports Server (NTRS)

    Houte, F. A.; Mckee, H. B.; Patten, T. C.

    1976-01-01

    Device has three integral, equally spaced leaf springs. Springs separate outer vacuum jacket from fluid carrying line, yet minimize conductive heat leaks and liquid boiloff. One-piece heat spring has sufficient flexibility to accommodate differential thermal expansion of inner and outer line.

  15. Cleaner Vacuum-Bag Curing

    NASA Technical Reports Server (NTRS)

    Clemons, J. M.; Penn, B. G.; Ledbetter, Frank E., III; Daniels, J. G.

    1987-01-01

    Improvement upon recommended procedures saves time and expense. Autoclave molding in vacuum bag cleaner if adhesive-backed covering placed around caul plate as well as on mold plate. Covering easy to remove after curing and leaves caul plate free of resin deposits.

  16. Quantum Vacuum Structure and Cosmology

    SciTech Connect

    Rafelski, Johann; Labun, Lance; Hadad, Yaron; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC

    2011-12-05

    Contemporary physics faces three great riddles that lie at the intersection of quantum theory, particle physics and cosmology. They are: (1) The expansion of the universe is accelerating - an extra factor of two appears in the size; (2) Zero-point fluctuations do not gravitate - a matter of 120 orders of magnitude; and (3) The 'True' quantum vacuum state does not gravitate. The latter two are explicitly problems related to the interpretation and the physical role and relation of the quantum vacuum with and in general relativity. Their resolution may require a major advance in our formulation and understanding of a common unified approach to quantum physics and gravity. To achieve this goal we must develop an experimental basis and much of the discussion we present is devoted to this task. In the following, we examine the observations and the theory contributing to the current framework comprising these riddles. We consider an interpretation of the first riddle within the context of the universe's quantum vacuum state, and propose an experimental concept to probe the vacuum state of the universe.

  17. Vacuum barrier for excimer lasers

    DOEpatents

    Shurter, Roger P.

    1992-01-01

    A barrier for separating the vacuum area of a diode from the pressurized gas area of an excimer laser. The barrier is a composite material comprising layers of a metal such as copper, along with layers of polyimide, and a matrix of graphite fiber yarns impregnated with epoxy. The barrier is stronger than conventional foil barriers, and allows greater electron throughput.

  18. Vacuum barrier for excimer lasers

    DOEpatents

    Shurter, R.P.

    1992-09-15

    A barrier for separating the vacuum area of a diode from the pressurized gas area of an excimer laser. The barrier is a composite material comprising layers of a metal such as copper, along with layers of polyimide, and a matrix of graphite fiber yarns impregnated with epoxy. The barrier is stronger than conventional foil barriers, and allows greater electron throughput. 3 figs.

  19. Vacuum Flushing of Sewer Solids

    EPA Science Inventory

    The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

  20. Vacuum-insulated catalytic converter

    DOEpatents

    Benson, David K.

    2001-01-01

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

  1. Plates for vacuum thermal fusion

    DOEpatents

    Davidson, James C.; Balch, Joseph W.

    2002-01-01

    A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

  2. A vacuum ultraviolet spectrophotometric system

    NASA Technical Reports Server (NTRS)

    Spann, James F.; Keffer, Charles E.; Zukic, Muamer

    1993-01-01

    The development of a vacuum ultraviolet spectrophotometric system for measuring transmittance and reflectance at variable angles is presented. Using various detectors and sources, the spectrophotometric system has been used for wavelengths from 80 nm to 300 nm with optical components up to 80 mm in diameter. The capability exists to make measurements through the visible range.

  3. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    SciTech Connect

    Dr. M.A. Ebadian

    2000-01-13

    The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process.

  4. Degassing procedure for ultrahigh vacuum

    NASA Technical Reports Server (NTRS)

    Moore, B. C.

    1979-01-01

    Calculations based on diffusion coefficients and degassing rates for stainless-steel vacuum chambers indicate that baking at lower temperatures for longer periods give lower ultimate pressures than rapid baking at high temperatures. Process could reduce pressures in chambers for particle accelerators, fusion reactors, material research, and other applications.

  5. Heavy-ion inertial fusion: influence of target gain on accelerator parameters for vacuum-propagation regimes in reaction chambers

    SciTech Connect

    Mark, J.W.K.; Bangerter, R.O.; Barletta, W.A.; Fawley, W.M.; Judd, D.L.

    1982-03-04

    Target physics imposes requirements on the design of inertial fusion drivers. The influence of beam propagation in near vacuum fusion reaction chambers is evaluated for the relation between target gain and the phase-space requirements of heavy-ion accelerators. Initial results suggest that neutralization of the ion beam has a much greater positive effect than the deleterious one of beam stripping provided that the fusion chamber pressure is < 10/sup -3/ torr (of Li vapor or equivalent).

  6. Vacuum polarization and Hawking radiation

    NASA Astrophysics Data System (ADS)

    Rahmati, Shohreh

    Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.

  7. A Neutral Beam Injector Upgrade for NSTX

    SciTech Connect

    T. Stevenson; B McCormack; G.D. Loesser; M. Kalish; S. Ramakrishnan; L. Grisham; J. Edwards; M. Cropper; G. Rossi; A. von Halle; M. Williams

    2002-01-18

    The National Spherical Torus Experiment (NSTX) capability with a Neutral Beam Injector (NBI) capable of 80 kiloelectronvolt (keV), 5 Megawatt (MW), 5 second operation. This 5.95 million dollar upgrade reused a previous generation injector and equipment for technical, cost, and schedule reasons to obtain these specifications while retaining a legacy capability of 120 keV neutral particle beam delivery for shorter pulse lengths for possible future NSTX experiments. Concerns with NBI injection included power deposition in the plasma, aiming angles from the fixed NBI fan array, density profiles and beam shine through, orbit losses of beam particles, and protection of the vacuum vessel wall against beam impingement. The upgrade made use of the beamline and cryo panels from the Neutral Beam Test Stand facility, existing power supplies and controls, beamline components and equipment not contaminated by tritium during DT [deuterium-tritium] experiments, and a liquid Helium refrigerator plant to power and cryogenically pump a beamline and three ion sources. All of the Tokamak Fusion Test Reactor (TFTR) ion sources had been contaminated with tritium, so a refurbishment effort was undertaken on selected TFTR sources to rid the three sources destined for the NSTX NBI of as much tritium as possible. An interconnecting duct was fabricated using some spare and some new components to attach the beamline to the NSTX vacuum vessel. Internal vacuum vessel armor using carbon tiles was added to protect the stainless steel vacuum vessel from beam impingement in the absence of plasma and interlock failure. To date, the NBI has operated to 80 keV and 5 MW and has injected requested power levels into NSTX plasmas with good initial results, including high beta and strong heating characteristics at full rated plasma current.

  8. High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

    SciTech Connect

    Yushkov, Georgy Yu.; Anders, A.

    2008-06-19

    Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ~;; 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 ?s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states.

  9. Materials for ultra-high vacuum

    SciTech Connect

    Lee, G.

    1989-08-15

    This report discusses materials for use in ultrahigh vacuum systems of 1 {times} 10{sup {minus}9} Torr or lower. The author briefly discusses alloys, solders, insulators and joining methods for vacuum systems. (JDL)

  10. Vacuum casting of thick polymeric films

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Moacanin, J.

    1979-01-01

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

  11. Ceramic-to-metal vacuum seal

    NASA Technical Reports Server (NTRS)

    Sackerlotzky, O. H.

    1979-01-01

    Knife-edge sealing technique forms reliable, vacuum-tight bonds between materials having very different thermal-expansion characteristics. Seal is thin and flexible and absorb shear, hoop, and bonding stresses at joint so that seal remains vacuum tight.

  12. A method of measuring the amplitude-modulated vacuum field near a conducting mirror

    NASA Technical Reports Server (NTRS)

    Youn, Sun-Hyun; Lee, Jai-Hyung; Chang, Joon-Sung

    1994-01-01

    Electromagnetic fields of the vacuum mode near a conducting mirror are modified with respect to those in free space, with their amplitudes having a sinusoidal spatial dependence from the mirror. Therefore if we combine this spatially amplitude-modulated vacuum field mode and intense coherent light with a beam splitter, we may detect this fluctuation of the vacuum mode in a homodyne detection scheme. It will give a new method to produce squeezed states of light with a single mirror placed close to an unused port of a beam splitter. We show that the amplitude fluctuation of the combined light can be reduced by a factor of 2 below that of the coherent light. We also discuss the limitations due to the finite line width of the laser and the effective absorption length of the photodiodes.

  13. A Review of Maintenance of Vacuum inside Vacuum Insulation Panels

    NASA Astrophysics Data System (ADS)

    Yang, Chun Guang; Xu, Lie

    The growing concerns over global energy crisis and the phasing out of polyurethane foams blown with CFC-11, which has high Ozone Depletion Potential(ODP), have pushed thermal insulation technology to improve its efficiency. Vacuum Insulation Panel(VIP) has been regarded as a super thermal insulation material with a thermal resistance of about 5-10 times higher than conventional thermal insulation. Appropriate vacuum in VIP is one of the most important factors contributing to the long term heat insulation performance of VIP. In this paper, the researches on three factors, which influence internal pressure inside VIP, including gas and water vapor permeation through the barrier, gas absorption by getters and desiccants and outgassing of the kernel, were reviewed respectively. Following this, the research emphasis and suggestions, which should be paid attention to, were summarized.

  14. Switching Circuit for Shop Vacuum System

    NASA Technical Reports Server (NTRS)

    Burley, R. K.

    1987-01-01

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

  15. Microscopic Rayleigh Droplet Beams

    NASA Astrophysics Data System (ADS)

    Doak, R. B.

    2005-11-01

    A periodically triggered Rayleigh Droplet Beam (RDB) delivers a perfectly linear and periodic stream of identical, monoenergetic droplets that are phase-locked to the trigger signal. The droplet diameter and spacing are easily adjusted of choice of nozzle diameter and trigger frequency. Any liquid of low viscosity may be emloyed as the beam fluid. Although the field of nanofluidics is expanding rapidly, little effort has yet been devoted to ``external flows'' such as RDB's. At ASU we have generated RDB's of water and methanol down to 2 microns in droplet diameter. Nozzle clogging is the sole impediment to smaller droplets. Microscopic Rayleigh droplet beams offer tremendous potential for fundamental physical measurements, fluid dynamics research, and nanofabrication. This talk will describe the apparatus and techniques used at ASU to generate RDB's (surprisingly simple and inexpensive), discuss the triboelectric phenomena that play a role (surprisingly significant), present some initial experimental fluid dynamics measurements, and briefly survey RDB applications. Our particular interest in RDB's is as microscopic transport systems to deliver hydrated, undenatured proteins into vacuum for structure determination via serial diffraction of x-rays or electrons. This may offer the first general method for structure determination of non-crystallizable proteins.

  16. Gravitational vacuum polarization. II. Energy conditions in the Boulware vacuum

    SciTech Connect

    Visser, M.

    1996-10-01

    Building on techniques developed in the preceding paper, I investigate the various pointwise and averaged energy conditions for the quantum stress-energy tensor corresponding to a conformally coupled massless scalar field in the Boulware vacuum. I work in the test-field limit, restrict attention to the Schwarzschild geometry, and invoke a mixture of analytical and numerical techniques. In contradistinction to the case of the Hartle-Hawking vacuum, wherein violations of the energy conditions were confined to the region between the event horizon and the unstable photon orbit, I show that in the Boulware vacuum (1) all standard (pointwise and averaged) energy conditions are violated throughout the exterior region, all the way from spatial infinity down to the event horizon, and (2) outside the event horizon the standard pointwise energy conditions are violated in a maximal manner: They are violated at all points and for all null or timelike vectors. (The region inside the event horizon is considerably messier and of dubious physical relevance. Nevertheless, the standard pointwise energy conditions seem to be violated even inside the event horizon.) I argue that this is highly suggestive evidence, pointing to the fact that general self-consistent solutions of semiclassical quantum gravity might {ital not} satisfy the energy conditions and may in fact for certain quantum fields and certain quantum states violate {ital all} the energy conditions. {copyright} {ital 1996 The American Physical Society.}

  17. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes...

  18. 46 CFR 154.804 - Vacuum protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Vacuum protection. 154.804 Section 154.804 Shipping... Systems § 154.804 Vacuum protection. (a) Except as allowed under paragraph (b) of this section, each cargo tank must have a vacuum protection system meeting paragraph (a)(1) of this section and either...

  19. Drying leather with vacuum and toggling sequentially

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated a drying method that will enable leather to be dried under vacuum and stretch sequentially to improve area yield. Vacuum drying offers fast speed at a low temperature, which would be advantageous to heat-vulnerable chrome-free leather. Adding a toggle action after vacuum drying cou...

  20. Utilize Vacuum Forming to Make Interdisciplinary Connections

    ERIC Educational Resources Information Center

    Love, Tyler S.; Valenza, Frank

    2011-01-01

    The concept of vacuum forming has been around since the 19th century, despite not being fully utilized in industry until the 1950s. In the past, industrial arts classes have used vacuum-forming projects to concentrate solely on the manufacturing process and the final product. However, vacuum forming is not just an old industrial arts activity; it…

  1. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes...

  2. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe....

  3. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe....

  4. 46 CFR 154.804 - Vacuum protection.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Vacuum protection. 154.804 Section 154.804 Shipping... Systems § 154.804 Vacuum protection. (a) Except as allowed under paragraph (b) of this section, each cargo tank must have a vacuum protection system meeting paragraph (a)(1) of this section and either...

  5. 46 CFR 154.804 - Vacuum protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Vacuum protection. 154.804 Section 154.804 Shipping... Systems § 154.804 Vacuum protection. (a) Except as allowed under paragraph (b) of this section, each cargo tank must have a vacuum protection system meeting paragraph (a)(1) of this section and either...

  6. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe....

  7. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe....

  8. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes...

  9. 14 CFR 25.1433 - Vacuum systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe....

  10. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes...

  11. 46 CFR 154.804 - Vacuum protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Vacuum protection. 154.804 Section 154.804 Shipping... Systems § 154.804 Vacuum protection. (a) Except as allowed under paragraph (b) of this section, each cargo tank must have a vacuum protection system meeting paragraph (a)(1) of this section and either...

  12. 14 CFR 29.1433 - Vacuum systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes...

  13. Vacuum pipe for e/sup +/e/sup -/ interactions

    SciTech Connect

    Hoard, C.T.

    1982-10-01

    The design, fabrication and testing of the beryllium vacuum chamber within the Mark II detector at SLAC is described. The Be chamber encloses one interaction point of the PEP circulating ring and is a part of its beam pipe. The Be chamber is captured within the Secondary Vertex Detector (SVD), a drift chamber, which is in turn centered in the Mark II drift chamber. Both ends of the beryllium pipe are brazed to aluminum/stainless transitions for connection to stainless steel bellows. A concentric radiation-screen liner of titanium foil runs the full length of the beryllium pipe.

  14. Improving the Bevatron vacuum to 10/sup -10/ torr

    SciTech Connect

    Avery, R.; Elioff, T.; Grunder, H.

    1981-03-01

    Pressure of approx. 10/sup -10/ torr is needed in the Bevatron to accelerate partially-stripped very-heavy ions (e.g. U/sup 69 +/) in the Bevatron without significant loss due to interactions with the residual gas. This ultra-high vacuum will be achieved by installing (summer and fall 1981) a cryogenic liner, mostly 12/sup 0/K, surrounding the Bevatron circulating beam. The novel construction features are presented along with results from successful tests of prototype sections. This is believed to be the largest application of cryogenic pumping to particle accelerators yet undertaken.

  15. Decoherence delays false vacuum decay

    NASA Astrophysics Data System (ADS)

    Bachlechner, Thomas C.

    2013-05-01

    We show that gravitational interactions between massless thermal modes and a nucleating Coleman-de Luccia bubble may lead to efficient decoherence and strongly suppress metastable vacuum decay for bubbles that are small compared to the Hubble radius. The vacuum decay rate including gravity and thermal photon interactions has the exponential scaling \\Gamma \\sim \\Gamma _{CDL}^{2}, where ΓCDL is the Coleman-de Luccia decay rate neglecting photon interactions. For the lowest metastable initial state an efficient quantum Zeno effect occurs due to thermal radiation of temperatures as low as the de Sitter temperature. This strong decoherence effect is a consequence of gravitational interactions with light external mode. We argue that efficient decoherence does not occur for the case of Hawking-Moss decay. This observation is consistent with requirements set by Poincaré recurrence in de Sitter space.

  16. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    SciTech Connect

    William S. McPhee

    2001-08-31

    The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites.

  17. Deflated--victims of vacuum.

    PubMed

    Sanders, Roy E

    2007-04-11

    Atmospheric pressure combined with a partial vacuum within chemical plant or refinery tanks can result in some ego-deflating moments. This article will review three catastrophic vessel failures in detail and touch on several other incidents. A 4000-gal acid tank was destroyed by a siphoning action; a well maintained tank truck was destroyed during a routine delivery; and a large, brand new refinery mega-vessel collapsed as the steam within it condensed. Seasoned engineers are aware of the frail nature of tanks and provide safeguards or procedures to limit damages. The purpose of this paper is to ensure this new generation of chemical plant/refinery employees understand the problems of the past and take the necessary precautions to guard against tank damages created by partial vacuum conditions.

  18. Open vacuum tube in space.

    PubMed

    Gonfalone, A A; Arends, H J

    1979-11-01

    After having reviewed briefly the reliability of vacuum tubes on spacecraft, it is shown that the operation in space of a vacuum tube with an open structure is possible provided adequate measures are taken. The tube considered here is a multielectrode electron gun emitting electrons into space, in order to control the potential of a satellite. To avoid the failure of the most sensitive element of the gun, namely the impregnated tungsten cathode, the gun design includes such characteristics as a slow warming up of the heater element, a reactivation program used in case of cathode contamination, and a clean opening system which is not contaminant. Similarities with communication tubes are considered and the advantages of open tubes are mentioned.

  19. Radiation reaction in quantum vacuum

    NASA Astrophysics Data System (ADS)

    Seto, Keita

    2015-02-01

    Since the development of the radiating electron theory by P. A. M. Dirac in 1938 [P. A. M. Dirac, Proc. R. Soc. Lond. A 167, 148 (1938)], many authors have tried to reformulate this model, called the "radiation reaction". Recently, this equation has become important for ultra-intense laser-electron (plasma) interactions. In our recent research, we found a stabilized model of the radiation reaction in quantum vacuum [K. Seto et al., Prog. Theor. Exp. Phys. 2014, 043A01 (2014)]. It led us to an updated Fletcher-Millikan charge-to-mass ratio including radiation. In this paper, I will discuss the generalization of our previous model and the new equation of motion with the radiation reaction in quantum vacuum via photon-photon scatterings and also introduce the new tensor d{E}^{μ ν α β }/dm, as the anisotropy of the charge-to-mass ratio.

  20. The Overpressured Student

    ERIC Educational Resources Information Center

    Weissbourd, Richard

    2011-01-01

    When it comes to academic achievement, many parents in upper- and middle-class communities have gone overboard, hiring tutors for their preschool children and going to enormous lengths to secure a spot for their child in a prestigious college. Even though poor children face many hardships, teenagers in affluent families suffer emotional and moral…