WorldWideScience

Sample records for ar gas filled

  1. Effect of adding Ar gas on the pulse height distribution of BF3-filled neutron detectors

    Indian Academy of Sciences (India)

    M Padalakshmi; A M Shaikh

    2008-11-01

    Boron trifluoride (BF3) proportional counters are used as detectors for thermal neutrons. They are characterized by high neutron sensitivity and good gamma discriminating properties. Most practical BF3 counters are filled with pure boron trifluoride gas enriched up to 96% 10B. But BF3 is not an ideal proportional counter gas. Worsening of plateau characteristics is observed with increasing radius due to impurities in gas. To overcome this problem, counters are filled with BF3 with an admixture of a more suitable gas such as argon. The dilution of BF3 with argon causes a decrease in detection efficiency, but the pulse height spectrum shows sharper peaks and more stable plateau characteristics than counters filled with pure BF3. The present investigations are under-taken to study the pulse height distribution and other important factors in BF3+Ar filled signal counters for neutron beam applications. Tests are performed with detectors with cylindrical geometry filled with BF3 gas enriched in 10B to 90%, and high purity Ar in different proportions. By analysing pulse height spectra, a value of 6.1 ± 0.2 has been obtained for the branching ratio of the 10B(,) reaction.

  2. Test beam studies of the TRD prototype filled with different gas mixtures based on Xe, Kr, and Ar

    Science.gov (United States)

    Celebi, E.; Brooks, T.; Joos, M.; Rembser, C.; Gurbuz, S.; Cetin, S. A.; Konovalov, S. P.; Tikhomirov, V. O.; Zhukov, K.; Fillipov, K. A.; Romaniouk, A.; Smirnov, S. Yu; Teterin, P. E.; Vorobev, K. A.; Boldyrev, A. S.; Maevsky, A.; Derendarz, D.

    2017-01-01

    Towards the end of LHC Run1, gas leaks were observed in some parts of the Transition Radiation Tracker (TRT) of ATLAS. Due to these leaks, primary Xenon based gas mixture was replaced with Argon based mixture in various parts. Test-beam studies with a dedicated Transition Radiation Detector (TRD) prototype were carried out in 2015 in order to understand transition radiation performance with mixtures based on Argon and Krypton. We present and discuss the results of these test-beam studies with different active gas compositions.

  3. Gas-Filled Capillary Model

    Science.gov (United States)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  4. Gas-filled separators - An overview

    CERN Document Server

    Leino, M

    2003-01-01

    Gas-filled recoil separators have been used in nuclear physics studies since the early fifties. Most notably, they have found use in the separation of evaporation residues of heavy and very heavy elements from unwanted background. Gas-filled separators, alone or coupled to a detector array, offer an efficient, fast, compact and relatively inexpensive solution for nuclear structure studies. A new application is the use of a gas-filled device as a pre-separator in the study of chemical properties of the heaviest elements. Other uses include systematic study of fusion evaporation cross sections and accelerator mass spectrometry. In this contribution, an overview on gas-filled recoil separators, their characteristics, fields of application and possible future developments is given.

  5. The Berkeley gas-filled separator

    CERN Document Server

    Ninov, V; McGrath, C A

    1998-01-01

    The BGS is being constructed at the 88-Inch Cyclotron at LBNL in Berkeley. The magnetic configuration of the BGS will allow a large angular acceptance and good suppression of primary beam particles. BGS operates as a mass spectrometer with a A/ Delta A approximately =200 and as a gas filled separator at pressures between 0.1-50 hPa. The reaction products recoiling off a thin target will be collected with efficiencies from 10-80at the focal plane. A Monte Carlo simulation program of the ion transport through the gas-filled magnets in combination of 3-dimensional TOSCA field maps has been developed and reproduces closely the experimental behavior of BGS. (9 refs).

  6. Improved Gas Filling and Sealing of an HC-PCF

    Science.gov (United States)

    Poberezhskiy, Ilya; Meras, Patrick; Chang, Daniel; Spiers, Gary

    2008-01-01

    An improved packaging approach has been devised for filling a hollow-core photonic-crystal fiber (HC-PCF) with a gas, sealing the HC-PCF to retain the gas, and providing for optical connections and, optionally, a plumbing fitting for changing or augmenting the gas filling. Gas-filled HC-PCFs can be many meters long and have been found to be attractive as relatively compact, lightweight, rugged alternatives to conventional gas-filled glass cells for use as molecular-resonance frequency references for stabilization of lasers in some optical-metrology, lidar, optical-communication, and other advanced applications. Prior approaches to gas filling and sealing of HC-PCFs have involved, variously, omission of any attempt to connectorize the PCF, connectorization inside a vacuum chamber (an awkward and expensive process), or temporary exposure of one end of an HC-PCF to the atmosphere, potentially resulting in contamination of the gas filling. Prior approaches have also involved, variously, fusion splicing of HC-PCFs with other optical fibers or other termination techniques that give rise to Fresnel reflections of about 4 percent, which results in output intensity noise.

  7. A Gas Proportional Scintillation Counter with krypton filling

    Science.gov (United States)

    Monteiro, C. M. B.; Mano, R. D. P.; Barata, E. C. G. M.; Fernandes, L. M. P.; Freitas, E. D. C.

    2016-12-01

    A Gas Proportional Scintillation Counter filled with pure krypton was studied. Energy resolution below 10% for 5.9-keV X-rays was obtained with this prototype. This value is much better than the energy resolution obtained with proportional counters or other MPGDs with krypton filling. The krypton electroluminescence scintillation and ionisation thresholds were found to be about 0.5 and 3.5 kV cm-1bar-1, respectively.

  8. Behavior of argon gas release from manganese oxide minerals as revealed by 40Ar/39Ar laser incremental heating analysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Manganese oxides in association with paleo- weathering may provide significant insights into the multiple factors affecting the formation and evolution of weathering profiles, such as temperature, precipitation, and biodiversity. Laser probe step-heating analysis of supergene hollandite and cryptomelane samples collected from central Queensland, Australia, yield well-defined plateaus andconsistent isochron ages, confirming the feasibility dating very-fined supergene manganese oxides by 40Ar/39Ar technique. Two distinct structural sites hostingAr isotopes can be identified in light of their degassing behaviors obtained byincremental heating analyses. The first site, releasing its gas fraction at thelaser power 0.2-0.4 W, yields primarily 40Aratm, 38Aratm, and 36Aratm (atmospheric Ar isotopes). The second sites yield predominantly 40Ar* (radiogenic 40Ar),39ArK, and 38ArK (nucleogenic components), at ~0.5-1.0 W. There is no significant Ar gas released at the laser power higher than 1.0 W, indicating the breakdown of the tunnel sites hosting the radiogenic and nucleogenic components. The excellent match between the degassing behaviors of 40Ar*, 39ArK, and 38ArK suggests that these isotopes occupy the same crystallographic sites and that 39ArK lossfrom the tunnel site by recoil during neutron irradiation and/or bake-out procedure preceding isotopic analysis does not occur. Present investigation supports that neither the overwhelming atmospheric 40Ar nor the very-fined nature of the supergene manganese oxides poses problems in extracting meaningful weathering geochronological information by analyzing supergene manganese oxides minerals.

  9. Shockwave compression of Ar gas at several initial densities

    Science.gov (United States)

    Dattelbaum, Dana M.; Goodwin, Peter M.; Garcia, Daniel B.; Gustavsen, Richard L.; Lang, John M.; Aslam, Tariq D.; Sheffield, Stephen A.; Gibson, Lloyd L.; Morris, John S.

    2017-01-01

    Experimental data of the principal Hugoniot locus of variable density gas-phase noble and molecular gases are rare. The majority of shock Hugoniot data is either from shock tube experiments on low-pressure gases or from plate impact experiments on cryogenic, liquefied gases. In both cases, physics regarding shock compressibility, thresholds for the on-set of shock-driven ionization, and even dissociation chemistry are difficult to infer for gases at intermediate densities. We have developed an experimental target design for gas gun-driven plate impact experiments on noble gases at initial pressures between 200-1000 psi. Using optical velocimetry, we are able to directly determine both the shock and particle velocities of the gas on the principal Hugoniot locus, as well as clearly differentiate ionization thresholds. The target design also results in multiply shocking the gas in a quasi-isentropic fashion yielding off-Hugoniot compression data. We describe the results of a series of plate impact experiments on Ar with starting densities between 0.02-0.05 g/cm3 at room temperature. Furthermore, by coupling optical fibers to the targets, we have measured the time-resolved optical emission from the shocked gas using a spectrometer coupled to an optical streak camera to spectrally-resolve the emission, and with a 5-color optical pyrometer for temperature determination.

  10. Method of Gas Filled Time of Flight in AMS Measurement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Isobaric interference is the main problem to be overcome in determination the long-livedradioisotopes. Energy loss method was used to measurement of these nuclides, but in the low energyaccelerator, the △E-E method is limited. In order to improve the power of isobaric identification in theaccelerator mass spectrometric measurements, a gas-filled time-of-flight (GF-TOF) spectrometric detectorhas been designed and set up.

  11. Thermal Performance Evaluation of Walls with Gas Filled Panel Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Atchley, Jerald Allen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-11-01

    Gas filled insulation panels (GFP) are very light weight and compact (when uninflated) advanced insulation products. GFPs consist of multiple layers of thin, low emittance (low-e) metalized aluminum. When expanded, the internal, low-e aluminum layers form a honeycomb structure. These baffled polymer chambers are enveloped by a sealed barrier and filled with either air or a low-conductivity gas. The sealed exterior aluminum foil barrier films provide thermal resistance, flammability protection, and properties to contain air or a low conductivity inert gas. This product was initially developed with a grant from the U.S. Department of Energy. The unexpanded product is nearly flat for easy storage and transport. Therefore, transportation volume and weight of the GFP to fill unit volume of wall cavity is much smaller compared to that of other conventional insulation products. This feature makes this product appealing to use at Army Contingency Basing, when transportation cost is significant compared to the cost of materials. The objective of this study is to evaluate thermal performance of walls, similar to those used at typical Barracks Hut (B-Hut) hard shelters, when GFPs are used in the wall cavities. Oak Ridge National Laboratory (ORNL) tested performance of the wall in the rotatable guarded hotbox (RGHB) according to the ASTM C 1363 standard test method.

  12. Systems and methods for regulating pressure of a filled-in gas

    Energy Technology Data Exchange (ETDEWEB)

    Stautner, Ernst Wolfgang; Michael, Joseph Darryl

    2016-05-03

    A system for regulating a pressure of a filled-in gas is presented. The system includes a reservoir that stores a reservoir gas adsorbed in a sorbent material at a storage temperature, a gas-filled tube containing the filled-in gas, a controller configured to determine a pressure change required in the filled-in gas based upon signals representative of a pressure of the filled-in gas inside the gas-filled tube and a required pressure threshold, determine an updated temperature of the sorbent material based upon the pressure change required in the filled-in gas, and regulate the pressure of the filled-in gas by controlling the reservoir to change the storage temperature of the sorbent material to reach the updated temperature of the sorbent material.

  13. New Pliocene-Pleistocene 40Ar/ 39Ar ages fill in temporal gaps in the Nicaraguan volcanic record

    Science.gov (United States)

    Saginor, Ian; Gazel, Esteban; Carr, Michael J.; Swisher, Carl C., III; Turrin, Brent

    2011-04-01

    The volcanic record of western Nicaragua documents a significant lull in volcanic activity that has persisted from the late Miocene (~ 7 Ma) to the formation of the modern volcanic front around 350 ka. This study fills this gap for the first time with samples collected in Northwest Nicaragua between Cosigüina and San Cristóbal volcanoes and with samples collected from the Nicaraguan Depression. We found two previously unknown volcanic units ranging from 3.6 to 1.3 Ma and the improved volcanic record allows us to reconstruct the geochemical evolution of the Nicaraguan arc. U/Th values increased by nearly threefold since the Miocene following the "carbonate crash" at 10 Ma, when dominantly carbonate sediment deposition shifted toward hemipelagic sediment deposition. This transition was thought to be abrupt, however our new data show that it took place gradually over the last 7 Ma. Northwest Nicaragua is a particularly interesting case study because it contains Middle Miocene volcanism on either side of the Nicaraguan Depression, the Coyol Formation (25-7 Ma) to the East and the Tamarindo Formation (14.7-11.7 Ma) to the West. The presence of Mid Miocene volcanism on either side of the Nicaraguan Depression has led to the hypothesis that the two coeval units, currently separated by ~ 100 km, were once connected and have since been separated by extension. Here, we present data suggesting that the Tamarindo and Coyol are geochemically distinct and therefore cannot be considered part of the same unit.

  14. The Thermo Scientific HELIX-SFT noble gas mass spectrometer: (preliminary) performance for 40Ar/39Ar geochronology

    Science.gov (United States)

    Barfod, D. N.; Mark, D. F.; Morgan, L. E.; Tomkinson, T.; Stuart, F.; Imlach, J.; Hamilton, D.

    2011-12-01

    The Thermo Scientific HELIX-platform Split Flight Tube (HELIX-SFT) noble gas mass spectrometer is specifically designed for simultaneous collection of helium isotopes. The high mass spur houses a switchable 1011 - 1012 Ω resistor Faraday cup and the low mass spur a digital pulse-counting secondary electron multiplier (SEM). We have acquired the HELIX-SFT with the specific intention to measure argon isotopes for 40Ar/39Ar geochronology. This contribution will discuss preliminary performance (resolution, reproducibility, precision etc.) with respect to measuring argon isotope ratios for 40Ar/39Ar dating of geological materials. We anticipate the greatest impact for 40Ar/39Ar dating will be increased accuracy and precision, especially as we approach the techniques younger limit. Working with Thermo Scientific we have subtly modified the source, alpha and collector slits of the HELIX-SFT mass spectrometer to improve its resolution for resolving isobaric interferences at masses 36 to 40. The enhanced performance will allow for accurate and precise measurement of argon isotopes. Preliminary investigations show that we can obtain a valley resolution of >700 and >1300 (compared to standard HELIX-SFT specifications of >400 and >700) for the high and low mass spurs, respectively. The improvement allows for full resolution of hydrocarbons (C3+) at masses 37 - 40 and almost full resolution at mass 36. The HELIX-SFT will collect data in dual collection mode with 40Ar+ ion beams measured using the switchable 1011 - 1012 Ω resistor Faraday cup and 39Ar through 36Ar measured using the SEM. The HELIX-SFT requires Faraday-SEM inter-calibration but negates the necessity to inter-calibrate multiple electron multipliers. We will further present preliminary data from the dating of mineral standards: Alder Creek sanidine, Fish Canyon sanidine and Mount Dromedary biotite (GA1550).

  15. Computing at the Dubna gas-filled recoil separator

    Science.gov (United States)

    Tsyganov, Yuri S.; Polyakov, Alexandr N.

    2006-03-01

    Simulation codes for the spectra of heavy implanted nuclei, applications for online data visualization and real time PC-based algorithms are considered. Special attention is paid to the application of real time techniques for radical suppression of background products in heavy-ion-induced nuclear reactions at the U-400 cyclotron of the Flerov Laboratory of Nuclear Reactions. The detection system of the Dubna gas-filled recoil separator (DGFRS) is also briefly described. Calculated heavy recoil spectra are compared with those measured in heavy-ion-induced nuclear reactions.

  16. Handbook for Gas Filled RF Cavity Aficionados'

    Energy Technology Data Exchange (ETDEWEB)

    Tollestrup, A.V.; Chung, Moses; Yonehara, Katsuya; /Fermilab

    2009-05-01

    The use of hydrogen gas filled RF cavities in muon cooling channels has been proposed by Rolland Johnson. Impressive results have been obtained toward attaining high voltage gradients and rapid training in preliminary tests done at the FNAL MTA facility. However, so far it has not been possible to test them under conditions where they were subject to the transversal of a high intensity particle beam. This note is an attempt to bring together a description of some of the pertinent physical processes that take place in the dilute plasma that is generated in the hydrogen gas by the beam. Two effects dominate. The first is that the free electrons generated can load down the cavity and transfer its energy to heating the gas. The second is a question of what happens to the plasma in the longer term. There is an enormous literature on the subject of the subject of dilute hydrogen plasmas and we can tap into this information in order to understand and predict the behavior of the cavity.

  17. A method of firing a gas filled switching tube

    Energy Technology Data Exchange (ETDEWEB)

    Bryukhanevich G.I.; Kolesov, G.V.; Lebedev, V.B.; Prokhorenko, V.I.

    1984-01-01

    A method is proposed for firing a gas filled switching tube which involves injecting a laser pulse of picosecond duration with an energy level higher than the firing threshold of the switching tube to the spark gap of the tube to be fired. In order to improve the operational stability of the tube, after a time period equal to delta T (with respect to the point where the first laser pulse is fed to the spark gap), a primary supplementary pulse is fed to the gap; the power level of this pulse is selected to be at least half the power level of the first, and the time interval delta T is selected depending on the value of the experimentally determined minimum delay time (t3 min) of the tube during firing by a separately selected primary pulse in a ratio of .5t3 min is less than delta T is less than or equal to t3 min.

  18. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    Science.gov (United States)

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

  19. Towards a liquid Argon TPC without evacuation filling of a 6$m^3$ vessel with argon gas from air to ppm impurities concentration through flushing

    CERN Document Server

    Curioni, A; Gendotti, A; Knecht, L; Lussi, D; Marchionni, A; Natterer, G; Resnati, F; Rubbia, A; Coleman, J; Lewis, M; Mavrokoridis, K; McCormick, K; Touramanis, C

    2010-01-01

    In this paper we present a successful experimental test of filling a volume of 6 $m^3$ with argon gas, starting from normal ambient air and reducing the impurities content down to few parts per million (ppm) oxygen equivalent. This level of contamination was directly monitored measuring the slow component of the scintillation light of the Ar gas, which is sensitive to $all$ sources of impurities affecting directly the argon scintillation.

  20. Laser-plasma interactions in large gas-filled hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.E.; Powers, L.V.; Berger, R.L. [and others

    1996-06-01

    Indirect-drive targets planned for the National Ignition Facility (NIF) laser consist of spherical fuel capsules enclosed in cylindrical Au hohlraums. Laser beams, arranged in cylindrical rings, heat the inside of the Au wall to produce x rays that in turn heat and implode the capsule to produce fusion conditions in the fuel. Detailed calculations show that adequate implosion symmetry can be maintained by filling the hohlraum interior with low-density, low-Z gases. The plasma produced from the heated gas provides sufficient pressure to keep the radiating Au surface from expanding excessively. As the laser heats this gas, the gas becomes a relatively uniform plasma with small gradients in velocity and density. Such long-scale-length plasmas can be ideal mediums for stimulated Brillouin Scattering (SBS). SBS can reflect a large fraction of the incident laser light before it is absorbed by the hohlraum; therefore, it is undesirable in an inertial confinement fusion target. To examine the importance of SBS in NIF targets, the authors used Nova to measure SBS from hohlraums with plasma conditions similar to those predicted for high-gain NIF targets. The plasmas differ from the more familiar exploding foil or solid targets as follows: they are hot (3 keV); they have high electron densities (n{sub e}=10{sup 21}cm{sup {minus}3}); and they are nearly stationary, confined within an Au cylinder, and uniform over large distances (>2 mm). These hohlraums have <3% peak SBS backscatter for an interaction beam with intensities of 1-4 x 10{sup 15} W/cm{sup 2}, a laser wavelength of 0.351{micro}m, f/4 or f/8 focusing optics, and a variety of beam smoothing implementations. Based on these conditions the authors conclude that SBS does not appear to be a problem for NIF targets.

  1. Development of a portable gas-filled ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Chae, K. Y.; Cha, S. M.; Gwak, M. S. [Sungkyunkwan University, Suwon (Korea, Republic of)

    2014-02-15

    A new portable gas-filled ionization chamber has been designed and constructed at the Physics Department of Sung Kyun Kwan University. To overcome the maximum count rate of ∼ 10{sup 5} particles per second of a conventional ionization chamber, which utilizes a Frisch grid, and to enhance the portability of a detector, we adopted the design of multiple electrodes and modified it from the original designs by Kimura et al. and Chae et al. The new design utilizes a stack of multiple electrodes installed perpendicular to the optical beam axis. This configuration provides a fast response time for the detector, which is essential for high-rate counting. The device has been tested with a {sup 241}Am (t{sub 1/2} = 432.2 years) radioactive α source, which mainly emits 5.486-MeV (branching ratio of 85%) and 5.443-MeV (branching ratio of 13%) α particles. An energy resolution of 6.3% was achieved.

  2. Multichannel Discharge Characteristics of Gas Switch Gap in SF6-N2 or SF6-Ar Gas Mixtures Under Nanosecond Triggering Pulses%Multichannel Discharge Characteristics of Gas Switch Gap in SF6-N2 or SF6-Ar Gas Mixtures Under Nanosecond Triggering Pulses

    Institute of Scientific and Technical Information of China (English)

    常家森; 王虎; 张乔根; 邱爱慈

    2011-01-01

    Experiments were carried out to ascertain multichannel discharge characteristics in a self-designed coaxial field-distortion gas switch filled with SFa-N2 or SF6-Ar gas mixtures of different mixing ratios. In these experiments, the pressure varied from 0.1 MPa to 0.2 MPa, the voltage pulse peak applied to the switch was in the range from 40 kV to 78 kV, and the pulse rise time was 11 ns. The static breakdown strength of the gas switch gap in the switch was also measured. The results show that in general the average number of discharge channels for SF6-Ar or SF6-N2 gas mixture which contains less SFa is larger than that for gas mixture which contains more SF6, however, the average number of channels almost keeps constant as the gas mixing ratio varies when the pulse rise rate is high enough. The static breakdown strength of the gas switch gap decreases slightly as the content of argon or nitrogen increases.

  3. Waste Package Neutron Absorber, Thermal Shunt, and Fill Gas Selection Report

    Energy Technology Data Exchange (ETDEWEB)

    V. Pasupathi

    2000-01-28

    Materials for neutron absorber, thermal shunt, and fill gas for use in the waste package were selected using a qualitative approach. For each component, selection criteria were identified; candidate materials were selected; and candidates were evaluated against these criteria. The neutron absorber materials evaluated were essentially boron-containing stainless steels. Two candidates were evaluated for the thermal shunt material. The fill gas candidates were common gases such as helium, argon, nitrogen, carbon dioxide, and dry air. Based on the performance of each candidate against the criteria, the following selections were made: Neutron absorber--Neutronit A978; Thermal shunt--Aluminum 6061 or 6063; and Fill gas--Helium.

  4. A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, C. A.; Blanchard, W. R.; Kozub, T. A.; Aristova, M.; McGahan, C.; Natta, S.; Pagdon, K.; Zelenty, J.

    2010-01-14

    wall acts as the primary heat exchanger. During removal, gas is pumped through the laser ports by turbo molecular-drag pumps (TM-DP). For the purpose of reducing organic based lubricants and seals, a magnetically levitated TM-DP is being investigated with pump manufacturers. Currently, magnetically levitated turbo molecular pumps are commercially available. The pumps will be exposed to thermal loads and ionizing radiation (tritium, Ar-41, post detonation neutrons). Although the TM-DP's will be subjected to these various radiations, current designs for similar pumping devices have been hardened and have the ability of locating control electronics in remote radiation shielded enclosures4. The radiation hardened TM-DP's will be 5 required to operate with minimal maintenance for periods of up to 18 continuous months. As part of this initial investigation for developing a conceptual engineering strategy for a gas fill solution, commercial suppliers of low pressure gas pumping systems have been contacted and engaged in this evaluation. Current technology in the area of mechanical pumping systems indicates that the development of a robust pumping system to meet the requirements of the FTF gas fill concept is within the limits of COTS equipment3,4.

  5. Simulations of indirectly driven gas-filled capsules at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. V.; Casey, D. T.; Eder, D. C.; Pino, J. E.; Smalyuk, V. A.; Remington, B. A.; Rowley, D. P.; Yeamans, C. B.; Tipton, R. E.; Barrios, M.; Benedetti, R.; Berzak Hopkins, L.; Bleuel, D. L.; Bond, E. J.; Bradley, D. K.; Caggiano, J. A.; Callahan, D. A.; Cerjan, C. J.; Clark, D. S.; Divol, L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-11-15

    Gas-filled capsules imploded with indirect drive on the National Ignition Facility have been employed as symmetry surrogates for cryogenic-layered ignition capsules and to explore interfacial mix. Plastic capsules containing deuterated layers and filled with tritium gas provide a direct measure of mix of ablator into the gas fuel. Other plastic capsules have employed DT or D{sup 3}He gas fill. We present the results of two-dimensional simulations of gas-filled capsule implosions with known degradation sources represented as in modeling of inertial confinement fusion ignition designs; these are time-dependent drive asymmetry, the capsule support tent, roughness at material interfaces, and prescribed gas-ablator interface mix. Unlike the case of cryogenic-layered implosions, many observables of gas-filled implosions are in reasonable agreement with predictions of these simulations. Yields of TT and DT neutrons as well as other x-ray and nuclear diagnostics are matched for CD-layered implosions. Yields of DT-filled capsules are over-predicted by factors of 1.4–2, while D{sup 3}He capsule yields are matched, as well as other metrics for both capsule types.

  6. Thermoregulated Nitric Cryosystem for Cooling Gas-Filled Detectors of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Zharkov I.P.

    2015-09-01

    Full Text Available Cryosystem for cooling and filling of gas-filled detectors of ionizing radiation with compressed inert gas on the basis of wide-nitrogen cryostat, which provides detetector temperature control in a range of 173 — 293 K and its stabilization with accuracy of ± 1°. The work was carried out within the Ukraine — NATO Program of Collaboration, Grant SfP #984655.

  7. A combined noble gas and {sup 40}Ar-{sup 39}Ar study of Salt Lake Crater xenolith SL322 from Oahu, Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    Trieloff, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Rocholl, A. [Heidelberg Univ. (Germany). Mineralogisch-Petrographisches Inst.; Jessberger, E.K. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)]|[Muenster Univ. (Germany). Inst. fuer Planetologie

    1998-12-31

    The microdistribution of noble gases in a garnet pyroxenite nodule from Salt Lake Crater (SLC), Oahu, Hawaii, was investigated by a detailed step-heating and -crushing analysis and a {sup 40}Ar-{sup 39}Ar-study. A noble gas component with MORB type argon, helium and neon resides in CO{sub 2}-rich fluid inclusions trapped in <30 km depth. This component was most probably derived from the nephelinitic SLC host magma and confirms the dominance of MORB type noble gases in the late post-erosional magmatic stages of Hawaiian volcanism, as suggested previsouly (Kurz et al., 1983; Valbracht et al., 1996). A second previously detected (Rocholl et al., 1996) low {sup 40}Ar/{sup 36}Ar ({proportional_to}5000) component turned out to be associated with two different reservoirs. The larger reservoir is most probably related to garnet, the other one is associated with low retentive sites containing few K and Cl and could not yet be adequately identified. The low {sup 40}Ar/{sup 36}Ar ({proportional_to}5000) component hosted by garnet can be interpreted as a mixture of MORB and plume type noble gas components with specific {sup 4}He/{sup 40}Ar ratios. The results demonstrate the complexity of the microdistribution of noble gases in ultramafic nodules and allow insight into plume induced metasomatism of the Hawaiian lithosphere. (orig.)

  8. A new shallow underground gas-proportional counting lab--first results and Ar-37 sensitivity.

    Science.gov (United States)

    Aalseth, C E; Day, A R; Fuller, E S; Hoppe, E W; Keillor, M E; Leferriere, B; Mace, E K; Merriman, J; Myers, A W; Overman, C T; Panisko, M E; Seifert, A; Warren, G A; Williams, R M

    2013-11-01

    A new ultra-low-background proportional counter was recently developed with an internal volume of 100 cm(3) and has been characterized at pressures from 1-10 atm with P-10 (90% Ar, 10% methane) gas. This design, along with a counting system providing event digitization and passive and active shielding, has been developed to complement a new shallow underground laboratory (30 m water-equivalent). Backgrounds and low-level reference materials have been measured, and system sensitivity for (37)Ar has been calculated.

  9. Effects of Natural Gas Compositions on CNG Fast Filling Process for Buffer Storage System

    Directory of Open Access Journals (Sweden)

    Farzaneh-Gord M.

    2013-02-01

    Full Text Available The accurate modeling of the fast-fill process occurring in Compressed Natural Gas (CNG fuelled vehicle storage cylinders is a complex process and should be thoroughly studied. Final in-cylinder conditions should meet appropriate cylinder safety standards. The composition of natural gas plays an important role on its thermodynamic properties and consequently, on the fast-fill process and the final conditions. Here, a theoretical analysis has been developed to study the effects of the natural gas composition on the filling process of an onboard Natural Gas Vehicle (NGV cylinder. The cylinder is assumed as a lumped system. The analysis is based on laws of thermodynamics and mass balance. Based on AGA8 Equation of State (EOS and thermodynamics relationships, the required properties of natural gas mixtures have been calculated. The results are presented for an adiabatic system. The results show that the compositions of natural gas have great effects on the filling process and final in-cylinder conditions. Furthermore, the gas with less methane percentage in its composition is more suitable for the filling process.

  10. X-ray detector for automatic exposure control using ionization chamber filled with xenon gas

    CERN Document Server

    Nakagawa, A; Yoshida, T

    2003-01-01

    This report refers to our newly developed X-ray detector for reliable automatic X-ray exposure control, which is to be widely used for X-ray diagnoses in various clinical fields. This new detector utilizes an ionization chamber filled with xenon gas, in contrast to conventional X-ray detectors which use ionization chambers filled with air. Use of xenon gas ensures higher sensitivity and thinner design of the detector. The xenon gas is completely sealed in the chamber, so that the influence of the changes in ambient environments is minimized. (author)

  11. Stabilization of gas-filled surge arrester’s characteristics by use of ionizing radiation

    Directory of Open Access Journals (Sweden)

    Brajović Dragan V.

    2012-01-01

    Full Text Available This paper investigates the stabilization of electrical discharges in gases by means of external ionizing radiation. Discharges in a gas-filled surge arrester model were studied in both passive and active regimes of the device. An originally developed model of the gas-filled surge arrester was used. Gas pressure and the interelectrode gap were the variable parameters in our measurements. Applied radiation types included α-particles, γ-rays, X-rays, and neutrons. Measurements were performed under highly controlled laboratory conditions. The combined measurement uncertainty of the applied procedure was estimated as being under the 5% level. The results obtained are followed by a theoretical explanation. The crucial result is the conclusion that ionizing radiation does not necessarily degrade the gas-filled surge arrester’s functionality but that it, rather, improves it under certain conditions.

  12. Ionization cross sections for electron scattering from metastable rare-gas atoms (Ne* and Ar*)

    Institute of Scientific and Technical Information of China (English)

    Zhang Yong-Zhi; Zhou Ya-Jun

    2013-01-01

    The optical-model approach has been used to investigate the electron-impact ionization of metastable rare-gas atoms.A complex equivalent-local polarization potential is obtained to describe the ionization continuum channels.We have calculated the cross sections for collisional ionization of the metastable atoms Ne* and Ar* by electrons in the energy range from threshold to 200 eV.The present results are in agreement with the available experimental measurements and other theoretical calculations.

  13. AMS Measurement of 36Cl With a Gas-filled Time of Flight Detector

    Institute of Scientific and Technical Information of China (English)

    GUANYong-jing; HEMing; RUANXiang-dong; WANGHui-juan; LIGuo-qiang; WUShao-yong; WUWei-ming; JIANGShan

    2003-01-01

    In order to determine 36Cl and 36S with high sensitivity by AMS, the present study has been done.Difference of time flight in the gas dependences to total energy, gas pressure in the chamber, and the flight length for isobars. The time resolution (FWHM) of the detector system is 800 ps without gas-filled when the ion energy is 72 MeV. Time straggling is growth with the increase of gas pressure in the chamber.Time straggling caused by the gas pressure is shown in Fig.1.

  14. Beam cooling using a gas-filled RFQ ion guide

    CERN Document Server

    Henry, S; De Saint-Simon, M; Jacotin, M; Képinski, J F; Lunney, M D

    1999-01-01

    A radiofrequency quadrupole mass filter is being developed for use as a high-transmission beam cooler by operating it in buffer gas at high pressure. Such a device will increase the sensitivity of on-line experiments that make use of weakly produced radioactive ion beams. We present simulations and some preliminary measurements for a device designed to cool the beam for the MISTRAL RF mass spectrometer on- line at ISOLDE. The work is carried out partly within the frame of the European Community research network: EXOTRAPS. (9 refs).

  15. 40Ar/39Ar dating of Quaternary volcanic ashes by multi-collection noble gas mass spectrometry: protocols, precision and intercalibration

    DEFF Research Database (Denmark)

    Storey, Michael; Rivera, Tiffany; Flude, Stephanie

    where potassium-bearing phenocrysts may contain relatively small amounts of radiogenic 40Ar. In 2005, the Quaternary Dating Laboratory, Roskilde University, installed a Nu-Instruments multi-collector Noblesse noble gas mass spectrometer, which is configured with a Faraday detector and three ion...

  16. Isobaric Identification Using Gas-Filled Time-of-Flight Measurements in an Accelerator Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-Jing; RUAN Xiang-Dong; HE Ming; WANG Hui-Juan; LI Guo-Qiang; WU Shao-Yong; DONG Ke-Jun; LIN Min; JIANG Shan

    2005-01-01

    @@ A gas-filled time-of-flight (GF-TOF) detector has been built and developed to improve the ability of isobaric identification in accelerator mass spectrometry (AMS) measurements, and a time resolution (without gas filled)of better than 350ps is achieved. The GF-TOF detector is tested by means of measuring a standard AgCl(36Cl/Cl = 7.6 × 10-9g/g) sample with the 36Cl ion energy of 64, 49 and 33MeV, respectively. 36Cl and 36S particles were successfully separated in the TOF spectra output from the GF-TOF detector. The comparison between the gas-filled time-of-flight method and the △E - E method is described. Some results relative to the GF-TOF method are given as well.

  17. The use of the gas-filled magnet technique for the detection of medium mass ions

    Energy Technology Data Exchange (ETDEWEB)

    Figueira, J.M., E-mail: figueira@tandar.cnea.gov.ar [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Buenos Aires (Argentina); Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Rehm, K.E. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Deibel, C.M. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Fernandez Niello, J.O. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, B1650BWA San Martin, Buenos Aires (Argentina); Greene, J.; Jiang, C.L.; Lee, H.Y. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Marley, S.T. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Physics Department, Western Michigan University, Kalamazoo, MI 49008 (United States); Pardo, R.C. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Patel, N. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States); Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem (Israel); and others

    2012-04-01

    The use of the gas-filled magnet technique for the detection of intermediate mass (A{approx} 20-40) recoil nuclei produced in (p,{alpha}) reactions in inverse kinematics has been investigated. Through a series of calibration measurements with {sup 27}Al, {sup 28,29}Si and {sup 33}S beams the optimum parameterization for calculating the average charge-state distribution in a gas-filled magnet has been determined. By measuring the magnetic rigidity, the time-of-flight and the differential energy loss of the particles at the focal plane of a gas-filled Enge Split Pole spectrograph it was possible to separate and identify the (p,{alpha}) reaction products from elastically scattered particles at very small scattering angles. This technique was then tested by measuring the p({sup 33}S,{sup 30}P){alpha} and p({sup 37}K,{sup 34}Cl){alpha} reactions.

  18. New gas-filled mode of the large-acceptance spectrometer VAMOS

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, C., E-mail: schmitt@ganil.f [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Rejmund, M.; Navin, A.; Lecornu, B.; Jacquot, B.; France, G. de; Lemasson, A.; Shrivastava, A. [GANIL, CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Greenlees, P.; Uusitalo, J. [Department of Physics, University of Jyvaskyla, P.O. Box 35, FI-40014, Jyvaskyla (Finland); Subotic, K. [VINCA Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia); Gaudefroy, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Theisen, Ch.; Sulignano, B. [CEA-Saclay DSM/IRFU/SPhN, F-91191 Gif/Yvette Cedex (France); Dorvaux, O.; Stuttge, L. [IPHC, UMR7178, IN2P3-CNRS et Universite Louis Pasteur, BP28, F-67037 Strasbourg (France)

    2010-09-21

    A new gas-filled operation mode of the large-acceptance spectrometer VAMOS at GANIL is reported. A beam rejection factor greater than 10{sup 10} is obtained for the {sup 40}Ca+{sup 150}Sm system at 196 MeV. The unprecedented transmission efficiency for the evaporation residues produced in this reaction is estimated to be around 80% for {alpha}x n channels and above 95% for x ny p channels. A detailed study of the performance of the gas-filled VAMOS and future developments are discussed. This new operation mode opens avenues to explore the potential of fusion reactions in various kinematics.

  19. Detection of a noble gas molecular ion, 36ArH+, in the Crab Nebula.

    Science.gov (United States)

    Barlow, M J; Swinyard, B M; Owen, P J; Cernicharo, J; Gomez, H L; Ivison, R J; Krause, O; Lim, T L; Matsuura, M; Miller, S; Olofsson, G; Polehampton, E T

    2013-12-13

    Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5- and 1234.6-gigahertz J = 1-0 and 2-1 rotational lines of (36)ArH(+) at several positions in the Crab Nebula, a supernova remnant known to contain both molecular hydrogen and regions of enhanced ionized argon emission. Argon-36 is believed to have originated from explosive nucleosynthesis in massive stars during core-collapse supernova events. Its detection in the Crab Nebula, the product of such a supernova event, confirms this expectation. The likely excitation mechanism for the observed (36)ArH(+) emission lines is electron collisions in partially ionized regions with electron densities of a few hundred per centimeter cubed.

  20. Shock formation in Ne, Ar, Kr, and Xe on DD gas puff implosions

    Science.gov (United States)

    Narkis, J.; Rahman, H. U.; Wessel, F. J.; Ney, P.; Beg, F.

    2016-10-01

    1- and 2-D simulations of a 1-cm radius, gas-puff implosion of Ne, Ar, Kr, and Xe liners onto a DD target are conducted using the discharge parameters for the Univ. Nevada, Reno, Zebra (1 MA, 125 ns) voltage driver and the resistive MHD code MACH2. During the run-in phase, initial†shock heating preheats the DD plasma, with subsequent stable, adiabatic compression heating the target to high energy density. The dynamics of the former in both the liner and target are investigated. It is shown that magnetic field transport to the liner/target interface does not occur prior to the run-in phase in Ne and Ar liners, yet does occur in Kr and Xe liners, and that magnetic field transport to the interface is a requirement for shock initiation, thus demonstrating the necessity for using a high-Z material in the Staged Z-pinch. Shock reflection off the axis and subsequent collision with the interface results in partial transmission into the liner, which manifests as current reversal, and consequently an enhanced Bθ gradient. 2-D simulations show that magneto-Rayleigh-Taylor instability growth decreases with increasing Z, with shock formation providing sufficient isolation to reproduce the current reversal and enhanced Bθ gradient observed in 1-D simulations. Advanced Research Projects Agency - Energy, DE-AR0000569.

  1. Utilizing gas-filled cavities for the generation of an intense muon source

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys [Brookhaven National Lab. (BNL), Upton, NY (United States); Neuffer, David V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-05-03

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  2. Utilizing Gas Filled Cavities for the Generation of an Intense Muon Source

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, Diktys; Neuffer, David V.

    2015-05-01

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  3. Ubiquitous argonium (ArH$^+$) in the diffuse interstellar medium -- a molecular tracer of almost purely atomic gas

    CERN Document Server

    Schilke, Peter; Mueller, Holger S P; Comito, Claudia; Bergin, Edwin A; Lis, Dariusz C; Gerin, Maryvonne; Black, John H; Wolfit, Mark; Indriolo, Nick; Pearson, John C; Menten, Karl M; Winkel, Benjamin; Sanchez-Monge, Alvaro; Moeller, Thomas; Godard, Benjamin; Falgarone, Edith

    2014-01-01

    We describe the assignment of a previously unidentified interstellar absorption line to ArH$^+$ and discuss its relevance in the context of hydride absorption in diffuse gas with a low H$_2$ fraction. The column densities along several lines of sight are determined and discussd in the framework of chemical models. The column densities of ArH$^+$ are compared to those of other species, tracing interstellar medium (ISM) components with different H$_2$ abundances. Chemical models are constructed, taking UV radiation and cosmic ray ionization into account. Due to the detection of two isotopologues, $^{36}$ArH$^+$ and $^{38}$ArH$^+$, we are confident about the carrier assignment to ArH$^+$. NeH$^+$ is not detected with a limit of [NeH$^+$]/[ArH$^+$] $\\le$ 0.1. The derived column densities agree well with the predictions of chemical models. ArH$^+$ is a unique tracer of gas with a fractional H$_2$ abundance of $10^{-4}- 10^{-3}$ and shows little correlation with H$_2$O$^+$, which traces gas with a fractional H$_2$ ...

  4. Hydrogen gas filling into an actual tank at high pressure and optimization of its thermal characteristics

    Science.gov (United States)

    Khan, Md. Tawhidul Islam; Monde, Masanori; Setoguchi, Toshiaki

    2009-09-01

    Gas with high pressure is widely used at present as fuel storage mode for different hydrogen vehicles. Different types of materials are used for constructing these hydrogen pressure vessels. An aluminum lined vessel and typically carbon fiber reinforced plastic (CFRP) materials are commercially used in hydrogen vessels. An aluminum lined vessel is easy to construct and posses high thermal conductivity compared to other commercially available vessels. However, compared to CFRP lined vessel, it has low strength capacity and safety factors. Therefore, nowadays, CFRP lined vessels are becoming more popular in hydrogen vehicles. Moreover, CFRP lined vessel has an advantage of light weight. CFRP, although, has many desirable properties in reducing the weight and in increasing the strength, it is also necessary to keep the material temperature below 85 °C for maintaining stringent safety requirements. While filling process occurs, the temperature can be exceeded due to the compression works of the gas flow. Therefore, it is very important to optimize the hydrogen filling system to avoid the crossing of the critical limit of the temperature rise. Computer-aided simulation has been conducted to characterize the hydrogen filling to optimize the technique. Three types of hydrogen vessels with different volumes have been analyzed for optimizing the charging characteristics of hydrogen to test vessels. Gas temperatures are measured inside representative vessels in the supply reservoirs (H2 storages) and at the inlet to the test tank during filling.

  5. Influence of the nitrogen gas addition in the Ar shielding gas on the erosion-corrosion of tube-to-tube sheet welds of hyper duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye-Jin; Jeon, Soon-Hyeok; Kim, Soon-Tae; Lee, In-Sung; Park, Yong-Soo [Yonsei University, Seoul (Korea, Republic of)

    2014-03-15

    Duplex stainless steels with nearly equal fraction of the ferrite(α) phase and austenite(γ) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE= wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of α-phase and γ-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of Cr{sub 2}N are the key points of this study. The primary results of this study are as follows. The addition of N{sub 2} to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the α-phase to γ-phase, increasing the fraction of γ-phase as well as decreasing the precipitation of Cr2N. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing N{sub 2} decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of γ-phase and the stability of passive film according to the addition N{sub 2} gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion.

  6. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  7. Hydro-Coupling Effects on Compression Symmetry in Gas-Filled Hohlraum Experiments at the Omega Laser

    Energy Technology Data Exchange (ETDEWEB)

    Dewalds, E L; Pollaine, S W; Landen, O L; Amendt, P A; Turner, R E; Wallace, R; Campbell, K M; Glenzer, S H

    2003-08-26

    Ignition hohlraum designs use low Z gas fill to slow down the inward progress of high Z ablated plasma from the hohlraum walls preventing large laser spot motion and capsule drive asymmetries. In order to optimize the ignition design, the gas hydro-coupling effect to a fusion capsule asymmetry is presently being assessed in experiments at the Omega laser facility with gas filled hohlraums and foam balls. Our experiments measure the effects of the pressure spike that is generated by direct gas heating by the drive laser beams on the capsule surrogate for various hohlraum gas fill densities (0-2.5 mg/cc). To isolate the effect of the gas-hydro coupling pressure, we have begun by using plastic ''hohlraums'' to reduce the x-ray ablation pressure. The foam ball images measured by x-ray backlighting show increasing pole-hot pressure asymmetry for increasing gas pressure. In addition, the gas hydrodynamics is studied by imaging of a low concentration Xe gas fill dopant. The gas fill self-emission. shows the early pressure spike and its propagation towards the foam ball, as well as the gas stagnation on the holraum axis at later times, both contributing to the capsule asymmetry. These first gas hydro-coupling results are compared to LASNEX simulations.

  8. Recent Studies of Proton Drip-Line Nuclei Using the Berkeley Gas-Filled Separator

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.W.; Batchelder, J.C.; Ninov, V.; Gregorich, K.E.; Toth, K.S.; Bingham, C.R.; Piechaczek, A.; Xu, X.J.; Powell, J.; Joosten, R.; Cerny, J.

    1999-10-07

    The Berkeley Gas-filled Separator provides new research opportunities at Lawrence Berkeley National Laboratory's X-Inch Cyclotron. The use of this apparatus for the study of proton drip-line nuclides is discussed. Preliminary results of {sup 78}Kr bombardments of {sup 102}Pd targets at mid-target energies of 360, 375 and 385 MeV are presented. Improvements planned partially as a result of this measurement are also discussed.

  9. Ultraviolet Light Generation in Gas-Filled Kagome Photonic Crystal Fiber

    Science.gov (United States)

    Rodrigues, Sílvia M. G.; Facão, Margarida; Ferreira, Mário F. S.

    2015-03-01

    Kagome hollow-core photonic crystal fibers were found to be ideal for the occurrence of ultrafast non-linear optics. This article reports the optimal conditions for the generation of ultraviolet light using a gas filled kagome hollow-core-photonic crystal fiber. It is shown that by changing the pressure of the gas and the input pulse characteristics, the efficiency of conversion and quality of ultraviolet light can be improved, as well as tuning its central frequency. Results suggest that a highly coherent and tunable ultraviolet light source can be constructed, which can find numerous applications.

  10. Dynamics of blueshifted floating pulses in gas filled hollow-core photonic crystal fibers

    CERN Document Server

    Facao, M

    2013-01-01

    Frequency blueshifting was recently observed in light pulses propagating on gas filled hollow-core photonic crystal fibers where a plasma has been produced due to photoionization of the gas. One of the propagation models that is adequate to describe the actual experimental observations is here investigated. It is a nonlinear Schr\\"odinger equation with an extra term, to which we applied a self-similar change of variables and found its accelerating solitons. As in other NLS related models possessing accelerating solitons, there exist asymmetrical pulses that decay as they propagate in some parameter region that was here well defined.

  11. Metrological and operational performance of measuring systems used in vehicle compressed natural gas filling stations

    Energy Technology Data Exchange (ETDEWEB)

    Velosa, Jhonn F.; Abril, Henry; Garcia, Luis E. [CDT de GAS (Venezuela). Gas Technological Development Center Corporation

    2008-07-01

    Corporation CDT GAS financially supported by the Colombian government through COLCIENCIAS, carried out a study aimed at designing, developing and implementing in Colombia a calibration and metrological verification 'specialized service' for gas meters installed at dispensers of filling stations using compressed natural gas. The results permitted the identification of improving opportunities (in measuring systems, equipment and devices used to deliver natural gas) which are focused on achieving the highest security and reliability of trading processes of CNG for vehicles. In the development of the first stage of the project, metrological type variables were initially considered, but given the importance of the measuring system and its interaction with the various elements involving gas supply to the filling station, the scope of the work done included aspects related to the operational performance, that is, those influencing the security of the users and the metrological performance of the measuring system. The development of the second stage counted on the collaboration of national companies from the sector of CNG for vehicles, which permitted the carrying out of multiple calibrations to the measuring systems installed in the CNG dispensers, thus achieving, in a concrete way, valid and reliable technological information of the implemented procedures. (author)

  12. Differentiated muscles are mandatory for gas-filling of the Drosophila airway system

    Directory of Open Access Journals (Sweden)

    Yiwen Wang

    2015-12-01

    Full Text Available At the end of development, organs acquire functionality, thereby ensuring autonomy of an organism when it separates from its mother or a protective egg. In insects, respiratory competence starts when the tracheal system fills with gas just before hatching of the juvenile animal. Cellular and molecular mechanisms of this process are not fully understood. Analyses of the phenotype of Drosophila embryos with malformed muscles revealed that they fail to gas-fill their tracheal system. Indeed, we show that major regulators of muscle formation like Lame duck and Blown fuse are important, while factors involved in the development of subsets of muscles including cardiac and visceral muscles are dispensable for this process, suggesting that somatic muscles (or parts of them are essential to enable tracheal terminal differentiation. Based on our phenotypic data, we assume that somatic muscle defect severity correlates with the penetrance of the gas-filling phenotype. This argues that a limiting molecular or mechanical muscle-borne signal tunes tracheal differentiation. We think that in analogy to the function of smooth muscles in vertebrate lungs, a balance of physical forces between muscles and the elasticity of tracheal walls may be decisive for tracheal terminal differentiation in Drosophila.

  13. Efficient Spectral Broadening in the 100-W Average Power Regime Using Gas Filled Kagome HC-PCF and Pulse Compression

    CERN Document Server

    Emaury, Florian; Debord, Benoit; Ghosh, Debashri; Diebold, Andreas; Gerome, Frederic; Suedmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2014-01-01

    We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core Kagome Hollow-Core Photonic Crystal Fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a Kagome HC-PCF containing 13 bar of static Argon gas. Subsequent compression tests performed using 8.4% of the full available power resulted in a pulse duration as short as 88 fs using the spectrally broadened output from the fiber. Compressing the full transmitted power through the fiber (118 W) could lead to a compressed output of >100 W of average power and >100 MW of peak power with an average power compression efficiency of 88%. This simple laser system with only one ultrafast laser oscillator and a simple single-pass fiber pulse compressor, generating both high peak power >100 MW and sub-100-fs pulses at megahertz repetition rate, is very int...

  14. Detecting leaks in gas-filled pressure vessels using acoustic resonances

    Science.gov (United States)

    Gillis, K. A.; Moldover, M. R.; Mehl, J. B.

    2016-05-01

    We demonstrate that a leak from a large, unthermostatted pressure vessel into ambient air can be detected an order of magnitude more effectively by measuring the time dependence of the ratio p/f2 than by measuring the ratio p/T. Here f is the resonance frequency of an acoustic mode of the gas inside the pressure vessel, p is the pressure of the gas, and T is the kelvin temperature measured at one point in the gas. In general, the resonance frequencies are determined by a mode-dependent, weighted average of the square of the speed-of-sound throughout the volume of the gas. However, the weighting usually has a weak dependence on likely temperature gradients in the gas inside a large pressure vessel. Using the ratio p/f2, we measured a gas leak (dM/dt)/M ≈ - 1.3 × 10-5 h-1 = - 0.11 yr-1 from a 300-liter pressure vessel filled with argon at 450 kPa that was exposed to sunshine-driven temperature and pressure fluctuations as large as (dT/dt)/T ≈ (dp/dt)/p ≈ 5 × 10-2 h-1 using a 24-hour data record. This leak could not be detected in a 72-hour record of p/T. (Here M is the mass of the gas in the vessel and t is the time.)

  15. Impact of Filling Gas on Subharmonic Emissions of Phospholipid Ultrasound Contrast Agents.

    Science.gov (United States)

    Kanbar, Emma; Fouan, Damien; Sennoga, Charles A; Doinikov, Alexander A; Bouakaz, Ayache

    2017-02-14

    Subharmonic signals backscattered from gas-filled lipid-shelled microbubbles have generated significant research interest because they can improve the detection and sensitivity of contrast-enhanced ultrasound imaging. However, the emission of subharmonic signals is strongly characterized by a temporal dependence, the origins of which have not been sufficiently elucidated. The features that influence subharmonic emissions need to be identified not only to better develop next-generation microbubble contrast agents, but also to develop more efficient subharmonic imaging (SHI) modes and therapeutic strategies. We examined the effect of microbubble filling gas on subharmonic emissions. Phospholipid shelled-microbubbles with different gaseous compositions such as sulfur hexafluoride (SF6), octafluoropropane (C3F8) or decafluorobutane (C4F10), nitrogen (N2)/C4F10 or air were insonated using a driving frequency of 10 MHz and peak negative pressure of 450 kPa, and their acoustic responses were tracked by monitoring both second harmonic and subharmonic emissions. Microbubbles were first acoustically characterized with their original gas and then re-characterized after substitution of the original gas with air, SF6 or C4F10. A measureable change in intensity of the subharmonic emissions with a 20- to 40-min delayed onset and increasing subharmonic emissions of the order 12-18 dB was recorded for microbubbles filled with C4F10. Substitution of C4F10 with air eliminated the earlier observed delay in subharmonic emissions. Significantly, substitution of SF6 for C4F10 successfully triggered a delay in the subharmonic emissions of the resultant agents, whereas substitution of C4F10 for SF6 eliminated the earlier observed suppression of subharmonic emissions, clearly suggesting that the type of filling gas contained in the microbubble agent influences subharmonic emissions in a time-dependent manner. Because our agents were dispersed in air-stabilized phosphate-buffered saline

  16. Simulation of beam-induced plasma in gas-filled rf cavities

    Science.gov (United States)

    Yu, Kwangmin; Samulyak, Roman; Yonehara, Katsuya; Freemire, Ben

    2017-03-01

    Processes occurring in a radio-frequency (rf) cavity, filled with high pressure gas and interacting with proton beams, have been studied via advanced numerical simulations. Simulations support the experimental program on the hydrogen gas-filled rf cavity in the Mucool Test Area (MTA) at Fermilab, and broader research on the design of muon cooling devices. space, a 3D electromagnetic particle-in-cell (EM-PIC) code with atomic physics support, was used in simulation studies. Plasma dynamics in the rf cavity, including the process of neutral gas ionization by proton beams, plasma loading of the rf cavity, and atomic processes in plasma such as electron-ion and ion-ion recombination and electron attachment to dopant molecules, have been studied. Through comparison with experiments in the MTA, simulations quantified several uncertain values of plasma properties such as effective recombination rates and the attachment time of electrons to dopant molecules. Simulations have achieved very good agreement with experiments on plasma loading and related processes. The experimentally validated code space is capable of predictive simulations of muon cooling devices.

  17. Study of high pressure gas filled RF cavities for muon collider

    CERN Document Server

    Yonehara, Katsuya

    2015-01-01

    Muon collider is a considerable candidate of the next-generation high-energy lepton collider machine. Operating an RF cavity in a multi-Tesla magnet is a critical requirement in a muon accelerator and a cooling channel. However, the maximum RF gradient in a vacuum RF cavity is strongly limited by an external magnetic field. Dense hydrogen gas filled RF cavity has been proposed since it is functional of generating a high RF accelerating gradient in a strong magnetic field and making an ionization cooling process at the same time. A critical issue of the cavity is a beam- induced plasma that consumes a considerable amount of RF power. The gas filled RF test cell was made and measured the RF loading due to a beam-induced plasma by using an intense proton beam at Fermilab. By doping an electronegative gas in dense hydrogen, the plasma loading effect is significantly mitigated. The result shows that the cavity is functional with a muon collider beam. Recent progress is shown in this presentation.

  18. First in situ determination of gas transport coefficients (DO2, DAr and DN2) from bulk gas concentration measurements (O2, N2, Ar) in natural sea ice

    DEFF Research Database (Denmark)

    Crabeck, O.; Delille, B.; Rysgaard, Søren

    2014-01-01

    bubbles escaping from the brine to the atmosphere—as the ice gets more permeable during melt—could be responsible for the previously reported high transport coefficients. These results underline that when there is no convective transport within the sea ice, the transport of gas by diffusion through......We report bulk gas concentrations of O2, N2, and Ar, as well as their transport coefficients, in natural landfast subarctic sea ice in southwest Greenland. The observed bulk ice gas composition was 27.5% O2, 71.4% N2, and 1.09% Ar. Most previous studies suggest that convective transport is the main...... driver of gas displacement in sea ice and have neglected diffusion processes. According to our data, brines were stratified within the ice, so that no convective transport could occur within the brine system. There- fore, diffusive transport was the main driver of gas migration. By analyzing the temporal...

  19. Automation of experiments at the Dubna gas-filled separator of recoil nuclei: Part II

    Science.gov (United States)

    Tsyganov, Yu. S.

    2015-03-01

    An application developed in Builder C++ (Windows) for the offline analysis of experimental data from the spectrometer of the gas-filled separator of recoil nuclei (Flerov Laboratory of Nuclear Reactions) based on the double-sided silicon strip detector is discussed. The automatic express method developed for calibrating 48 strips of the silicon position-sensitive detector based on the three most energetic spectral lines from the natYb + 48Ca▭*Th reaction is compared to the results produced by more rigorous calibration methods. The examples of spectra for this reaction and the results of filtering for the proposed calibration algorithm are given.

  20. Parameter monitoring system of the Dubna Gas-Filled Recoil Separator

    CERN Document Server

    Tsyganov, Y S; Sukhov, A M

    2015-01-01

    PC-based one-crate monitoring and control system of the Dubna Gas Filled Recoil Separator (DGFRS) is considered. It is developed for the long-term experiments at the U400 FLNR cyclotron and is aimed at the synthesis of super heavy nuclei in heavy ion induced complete fusion reactions. Parameters related to: a) beam and cyclotron; b) separator by itself, c) detection system, d) target and entrance window are measured and stored in the protocol file of the experiment. Special attention is paid to generating the alarm signals and implementing further the appropriate procedures

  1. BiCMOS amplifier-discriminator integrated circuit for gas-filled detector readout

    Energy Technology Data Exchange (ETDEWEB)

    Herve, C. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)]. E-mail: herve@esrf.fr; Dzahini, D. [Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Le Caer, T. [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Richer, J.-P. [Laboratoire de Physique Subatomique et de Cosmologie, Grenoble (France); Torki, K. [Laboratoire TIMA, Grenoble (France)

    2005-03-21

    The paper presents a 16-channel amplifier-discriminator designed in BiCMOS technology. It will be used for the binary parallel readout of gas-filled detectors being designed at the European Synchrotron Radiation Facility. The circuit (named AMS211) has been manufactured. The measured transimpedance gain (400 K{omega}), bandwidth (25 MHz) and noise (1570 e{sup -}+95 e{sup -}/pF ENC) well match the simulated results. The discriminator thresholds are individually controlled by built-in Digital to Analogue Converter. The experience gained with a first prototype of readout electronics indicates that the AMS211 should meet our requirements.

  2. Development of a Gas Filled Magnet spectrometer within the FIPPS project

    Science.gov (United States)

    Chebboubi, A.; Kessedjian, G.; Faust, H.; Blanc, A.; Jentschel, M.; Köster, U.; Materna, T.; Méplan, O.; Sage, C.; Serot, O.

    2016-06-01

    The Fission Product Prompt γ -ray Spectrometer, FIPPS, is under development to enable prompt γ -ray spectroscopy correlated with fission fragment identification. This will open new possibilities in the study of fission and of nuclear structure of neutron rich nuclei. FIPPS will consist of an array of γ and neutron detectors coupled with a fission fragment filter. The chosen solution for the filter is a Gas Filled Magnet (GFM). Both experimental and modeling work was performed in order to extract the key parameters of such a device and design the future GFM of the FIPPS project. Experiments performed with a GFM behind the LOHENGRIN spectrometer demonstrated the capability of additional beam purification.

  3. New Hadron Monitor By Using A Gas-Filled RF Resonator

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Fasce, Giorgio [ECONA, Rome; Flanagan, Gene [MUONS Inc., Batavia; Johnson, Rolland [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2015-05-01

    It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.

  4. Characterizing passive coherent population trapping resonance in a cesium vapor cell filled with neon buffer gas

    Institute of Scientific and Technical Information of China (English)

    Liu Zhi; Wang Jie-Ying; Diao Wen-Ting; He Jun; Wang Jun-Min

    2013-01-01

    We present a pair of phase-locked lasers with a 9.2-GHz frequency difference through the injection locking of a master laser to the RF-modulation sideband of a slave diode laser.Using this laser system,a coherent population trapping (CPT)signal with a typical linewidth of ~ 182 Hz is obtained in a cesium vapor cell filled with 30 Torr (4 kPa) of neon as the buffer gas.We investigate the influence of the partial pressure of the neon buffer gas on the CPT linewidth,amplitude,and frequency shift.The results may offer some references for CPT atomic clocks and CPT atomic magnetometers.

  5. The axial symmetric vibrations of cylindrical shell, filled by the flowing Gas-Liquid mixture

    Directory of Open Access Journals (Sweden)

    Grigoryan Sh.H.

    2011-09-01

    Full Text Available The problem of axial symmetric self–vibrations of the infinite long shell, filled by flowing gas bubbles of large and small sizes in fluid mixture is considered. The subsonic and supersonic regimes of the mixture flow are discussed. For vibration frequencies of the system under consideration are shown that shell frequencies with big bubbles–liquids mixture exceed the frequencies of system of with small gas bubbles–liquid mixture. In subsonic regime increasing of shell thickness brings to increasing of shell frequencies, as in case of shell with pure fluid. In subsonic regime the frequencies are increasing with decreasing of the flowing velocity, on the contrary, brings to decreasing of frequencies, similar to the case of shell with the pure fluid.

  6. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, Katsuya [Fermilab; Abrams, Robert [MUONS Inc., Batavia; Dinkel, Holly [U. Missouri, Columbia; Freemire, Ben [IIT, Chicago; Johnson, Rolland [MUONS Inc., Batavia; Kazakevich, Grigory [MUONS Inc., Batavia; Tollestrup, Alvin [Fermilab; Zwaska, Robert [Fermilab

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  7. Ion beam characteristics of the controlatron/zetatron family of the gas filled neutron tubes

    Energy Technology Data Exchange (ETDEWEB)

    Berg, R.S.; Shope, L.A.; O' Neal, M.L.; Boers, J.E.; Bickes, R.W. Jr.

    1981-03-01

    A gas filled tube used to produce a neutron flux with the D(T,He/sup 4/)n reaction is described. Deuterium and tritium ions generated in a reflex discharge are extracted and accelerated to 100 keV by means of an accelerator electrode onto a deutero-tritide target electrode. The electrodes are designed to focus the ion beam onto the target. Total tube currents consisting of extracted ions, unsuppressed secondary electrons, and ions generated by interactions with the background gas are typically 100 mA. The characteristics of the extracted ion beam are discussed. Accelerating voltages greater than 50 kV are required to focus the beam through the accelerator aperture for configurations that give beams with the proper energy density onto the target. The perveance of the beam is discussed. Maximum perveance values are 2 to 20 nanopervs. Tube focusing and neutron production characteristics are described.

  8. Factors that affect the efficiency of antisense oligodeoxyribonucleotide transfection by insonated gas-filled lipid microbubbles

    Science.gov (United States)

    Zhao, Ying-Zheng; Lu, Cui-Tao

    2008-03-01

    Objective: To investigate the factors that affect the efficiency of antisense oligodeoxyribonucleotide(AS-ODNs) transfection by insonated gas-filled lipid microbubbles. Methods: Lipid microbubbles filled with two types of gases-air and C3F8, were prepared respectively. An AS-ODNs sequence HA824 and a breast cancer cell line SK-BR-3 were used to define the various operating variables determining the transfection efficiency of insonated microbubbles. Two mixing methods, three levels of mixing speed, different mixing durations and various ultrasound initiation time after mixing were examined respectively. Transfection efficiency was detected by fluorescence microscopy. Results: C3F8 microbubbles gave higher levels of AS-ODNs transfection efficiency than air microbubbles in all test conditions. Transfection efficiency resulted from mixing method A (incubation of HA824 and microbubbles before mixing cells) did not show significant difference with that of mixing method B (without incubation of HA824 and microbubbles before mixing cells). Mixing speed, duration of mixing and ultrasound initiation time after mixing were central to determining HA824 transfection efficiency in vitro. The optimum parameters for SK-BR-3 cells were found at a mixing speed of 40-50 rpm for 30-60 s with less than 60 s delay before ultrasound. Conclusion: Ultrasound-mediated AS-ODNs transfection enhanced by C3F8-filled lipid microbubbles represents an effective avenue for AS-ODNs transfer.

  9. Factors that affect the efficiency of antisense oligodeoxyribonucleotide transfection by insonated gas-filled lipid microbubbles

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yingzheng [General Hospital of Beijing Military Command of PLA, Department of Clinical Pharmacology (China)], E-mail: lctuua@yahoo.com.cn; Lu Cuitao [Madam Medical Management Group (China)

    2008-03-15

    Objective: To investigate the factors that affect the efficiency of antisense oligodeoxyribonucleotide(AS-ODNs) transfection by insonated gas-filled lipid microbubbles. Methods: Lipid microbubbles filled with two types of gases-air and C{sub 3}F{sub 8}, were prepared respectively. An AS-ODNs sequence HA824 and a breast cancer cell line SK-BR-3 were used to define the various operating variables determining the transfection efficiency of insonated microbubbles. Two mixing methods, three levels of mixing speed, different mixing durations and various ultrasound initiation time after mixing were examined respectively. Transfection efficiency was detected by fluorescence microscopy. Results: C{sub 3}F{sub 8} microbubbles gave higher levels of AS-ODNs transfection efficiency than air microbubbles in all test conditions. Transfection efficiency resulted from mixing method A (incubation of HA824 and microbubbles before mixing cells) did not show significant difference with that of mixing method B (without incubation of HA824 and microbubbles before mixing cells). Mixing speed, duration of mixing and ultrasound initiation time after mixing were central to determining HA824 transfection efficiency in vitro. The optimum parameters for SK-BR-3 cells were found at a mixing speed of 40-50 rpm for 30-60 s with less than 60 s delay before ultrasound. Conclusion: Ultrasound-mediated AS-ODNs transfection enhanced by C{sub 3}F{sub 8}-filled lipid microbubbles represents an effective avenue for AS-ODNs transfer.

  10. High energy gas fracture experiments in liquid-filled boreholes: potential geothermal application

    Energy Technology Data Exchange (ETDEWEB)

    Cuderman, J.F.; Chu, T.Y.; Jung, J.; Jacobson, R.D.

    1986-07-01

    High Energy Gas Fracturing is a tailored pulse fracturing technique which uses propellants to obtain controlled fracture initiation and extension. Borehole pressurization rates can be tailored, by suitable choice of propellants, to produce four or eight fractures radiating from the wellbore. High Energy Gas Fracture (HEGF) research is conducted at DOE's Nevada Test Site (NTS) in a tunnel complex where experiments can be done under realistic in situ stress conditions (1400 psi (9.7 MPa) overburden stress). Pressure measurements are made in the test borehole during all fracturing experiments. Experiments are mined back to provide direct observation of fracturing obtained. The initial objective of HEGF research was to develop multiple fracturing technology for application in gas well stimulation. HEGF research at NTS and in Devonian shale demonstration tests has resulted in a completed technology for multiple fracturing in uncased, liquid-free wellbores. Current resarch is directed toward extending the technique to liquid-filled boreholes for application in geothermal in addition to gas and oil wells. For liquid-free boreholes, multiple fracturing is specified in terms of pressure risetime required for a given borehole diameter. Propellants are mixed to achieve the desired risetime using a semiempirical mixing equation. The same techniques were successfully applied to fracturing in liquid-filled wellbores. However, the addition of liquid in the borehole results in a significantly more complicated fracturing behavior. Hydrodynamic effects are significant. Multiple fractures are initiated but only some propagated. Multiple- and hydraulic-type fracturing and wellbore crushing have been observed in the same experiment. The potential of using HEGB for geothermal well stimulation has been demonstrated through the present experiments. 18 refs., 40 figs., 4 tabs.

  11. Continuous Measurements of Dissolved Ne, Ar, Kr, and Xe Ratios with a Field-Deployable Gas Equilibration Mass Spectrometer.

    Science.gov (United States)

    Manning, Cara C; Stanley, Rachel H R; Lott, Dempsey E

    2016-03-15

    Noble gases dissolved in natural waters are useful tracers for quantifying physical processes. Here, we describe a field-deployable gas equilibration mass spectrometer (GEMS) that provides continuous, real-time measurements of Ne, Ar, Kr, and Xe mole ratios in natural waters. Gas is equilibrated with a membrane contactor cartridge and measured with a quadrupole mass spectrometer, after in-line purification with reactive metal alloy getters. We use an electron energy of 35 V for Ne to eliminate isobaric interferences, and a higher electron energy for the other gases to improve sensitivity. The precision is 0.7% or better and 1.0% or better for all mole ratios when the instrument is installed in a temperature-controlled environment and a variable-temperature environment, respectively. In the lab, the accuracy is 0.9% or better for all gas ratios using air as the only calibration standard. In the field (and/or at greater levels of disequilbrium), the accuracy is 0.7% or better for Ne/Kr, Ne/Ar, and Ar/Kr, and 2.5% or better for Ne/Xe, Ar/Xe, and Kr/Xe using air as the only calibration standard. The field accuracy improves to 0.6% or better for Ne/Xe, Ar/Xe, and Kr/Xe when the data is calibrated using discrete water samples run on a laboratory-based mass spectrometer. The e-folding response time is 90-410 s. This instrument enables the collection of a large number of continuous, high-precision and accuracy noble gas measurements at substantially reduced cost and labor compared to traditional methods.

  12. High temperature corrosion of hot-dip aluminized steel in Ar/1%SO2 gas

    Science.gov (United States)

    Abro, Muhammad Ali; Lee, Dong Bok

    2017-01-01

    Carbon steels were hot-dip aluminized in Al or Al-1at%Si baths, and corroded in Ar/1%SO2 gas at 700-800 °C for up to 50 h. The aluminized layers consisted of not only an outer Al(Fe) topcoat that had interdispersed needle-like Al3Fe particles but also an inner Al-Fe alloy layer that consisted of an outer Al3Fe layer and an inner Al5Fe2 layer. The Si addition in the bath made the Al(Fe) topcoat thin and nonuniform, smoothened the tongue-like interface between the Al-Fe alloy layer and the substrate, and increased the microhardness of the aluminized layer. The aluminized steels exhibited good corrosion resistance by forming thin α-Al2O3 scales, along with a minor amount of iron oxides on the surface. The interdiffusion that occurred during heating made the aluminized layer thick and diffuse, resulting in the formation of Al5Fe2, AlFe and AlFe3 layers. It also smoothened the tongue-like interface, and decreased the microhardness of the aluminized layer. The non-aluminized steel formed thick, nonadherent, nonprotective (Fe3O4, FeS)-mixed scales.

  13. Mapping the Ionization State of Laser-Irradiated Ar Gas Jets With Multi-Wavelength Monochromatic X-Ray Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kugland, N L; Doppner, T; Kemp, A; Schaeffer, D; Glenzer, S H; Niemann, C

    2010-04-08

    Two-dimensional monochromatic images of fast-electron stimulated Ar K{alpha} and He-{alpha} x-ray self-emission have recorded a time-integrated map of the extent of Ar{sup {approx}6+} and Ar{sup 16+} ions, respectively, within a high density (10{sup 20} cm{sup -3} atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultra-high intensity (10{sup 19} W/cm{sup 2}, 200 fs) Ti:Sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for K{alpha}) and 201 (for He-{alpha}) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 {micro}m long) region of plasma emits K{alpha} primarily along the laser axis, while the He-{alpha} emission is confined to smaller hot spot (230 {micro}m long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry, which images in one dimension, indicate that the centroids of the K{alpha} and He-{alpha} emission regions are separated by approximately 330 {micro}m along the laser axis.

  14. Use of the gas-filled-magnet technique for particle identification at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.K.; Jiang, C.L.; Paul, M. [Hebrew Univ., Jerusalem (Israel)

    1995-08-01

    Reaction studies of interest to astrophysics with radioactive ion beams will be done mainly in inverse reaction kinematics, i.e., heavy particles bombarding a hydrogen target. The low energy of the outgoing heavy reaction products makes particle identification with respect to mass and nuclear charge a major challenge. For the planned {sup 18}F(p,{alpha}) experiment one expects five different types of particles in the outgoing channels: {sup 18}F and {sup 18}O (from elastic scattering of {sup 18}F and {sup 18}O on {sup 12}C), {sup 15}O and {sup 15}N (from the {sup 18}F and {sup 18}O induced (p,{alpha}) reactions) and {sup 12}C recoils from the polypropylene target. While mass determination can be achieved easily by time-of-flight (TOF) measurements, a determination of the nuclear charge presents a challenge, especially if the energy of the particles is below 500 keV/u. We studied the gas-filled magnet technique for Z-identification of light ions between Z = 6-9. In a gas-filled magnet the particles move with an average charge state {bar q} which in one parameterization is given by {bar q} = Z ln(avZ{sup {alpha}})/ln(bZ{sup {beta}}) where Z is the nuclear charge of the ions and v their velocity. Introducing into the expression for the magnetic rigidity B{rho} = mv/{bar q} results in a Z dependence of B{rho} which is valid to very low velocities. As a magnet we used the Enge split-pole spectrograph which was filled with nitrogen gas at a pressure of 0.5 Torr. The particles were detected in the focal plane with a 50 x 10 cm{sup 2} parallel-grid-avalanche counter which measured TOF and magnetic rigidity. The mass and Z separation was tested with {sup 13}C and {sup 18}O beams at energies of about 600 keV/u and recoil particles ranging from {sup 12}C to {sup 19}F. The Z-separation obtained at these energies was {triangle}Z/Z = 0.28 which is sufficient to separate individual elements for Z < 10.

  15. Expansion characteristics of twin combustion gas jets with high pressure in cylindrical filling liquid chamber

    Institute of Scientific and Technical Information of China (English)

    薛晓春; 余永刚; 张琦

    2013-01-01

    To deal with the problem of how to control the interior ballistic stability in the bulk-loaded liquid propellant gun, the expansion and mixing process of the twin combustion-gas jets with high temperature and pressure in a liquid medium is studied in the cylindrical filling liquid chamber. A series of the jet expansion shapes is obtained by using a high-speed photographic system. The influences of the jet pressure on the jet expansion shape are discussed. Based on the experiments, the three-dimensional mathematical model is established. The expansion processes of the twin gas jets in the liquid medium are simulated by means of fluent to get the pressure, density, temperature, velocity contours and evolutionary process of vortices. Results show that the jet external outline and tops are all irregular. The Kelvin-Helmholtz instability is shown in the whole expansion process. The numerical simulation results of the axial displacement of the twin gas jets in liquid agree well with the experiment.

  16. Universality of Coherent Raman Gain Suppression in Gas-Filled Broadband-Guiding Photonic Crystal Fibers

    Science.gov (United States)

    Hosseini, P.; Mridha, M. K.; Novoa, D.; Abdolvand, A.; Russell, P. St. J.

    2017-03-01

    As shown in the early 1960s, the gain in stimulated Raman scattering (SRS) is drastically suppressed when the rate of creation of phonons (via a pump-to-Stokes conversion) is exactly balanced by the rate of phonon annihilation (via a pump-to-anti-Stokes conversion). This occurs when the phonon coherence waves—synchronized vibrations of a large population of molecules—have identical propagation constants for both processes; i.e., they are phase-velocity matched. As recently demonstrated, hydrogen-filled photonic crystal fiber pumped in the vicinity of its zero-dispersion wavelength provides an ideal system for observing this effect. Here we report that Raman gain suppression is actually a universal feature of SRS in gas-filled hollow-core fibers and that it can strongly impair SRS even when the phase mismatch is high, particularly at high pump powers when it is normally assumed that nonlinear processes become more (not less) efficient. This counterintuitive result means that intermodal stimulated Raman scattering (for example, between LP01 and LP11 core modes) begins to dominate at high power levels. The results reported have important implications for fiber-based Raman shifters, amplifiers, or frequency combs, especially for operation in the ultraviolet, where the Raman gain is much higher.

  17. Development of a Gas Filled Magnet spectrometer coupled with the Lohengrin spectrometer for fission study

    Directory of Open Access Journals (Sweden)

    Materna T.

    2013-03-01

    Full Text Available The accurate knowledge of the fission of actinides is necessary for studies of innovative nuclear reactor concepts. The fission yields have a direct influence on the evaluation of the fuel inventory or the reactor residual power after shutdown. A collaboration between the ILL, LPSC and CEA has developed a measurement program on fission fragment distributions at ILL in order to measure the isotopic and isomeric yields. The method is illustrated using the 233U(n,f98Y reaction. However, the extracted beam from the Lohengrin spectrometer is not isobaric ions which limits the low yield measurements. Presently, the coupling of the Lohengrin spectrometer with a Gas Filled Magnet (GFM is studied at the ILL in order to define and validate the enhanced purification of the extracted beam. This work will present the results of the spectrometer characterisation, along with a comparison with a dedicated Monte Carlo simulation especially developed for this purpose.

  18. Applying the Different Statistical Tests in Analysis of Electrical Breakdown Mechanisms in Nitrogen Filled Gas Diode

    Science.gov (United States)

    Čedomir, A. Maluckov; Saša, A. Rančev; Miodrag, K. Radović

    2016-10-01

    This paper presents the results of our investigations of breakdown mechanisms, as well as a description of their influence on the distributions of time delay distributions, for a gas tube filled with nitrogen at 4 mbar. The values of the time delay are measured for different voltages, and the values of the relaxation times and their distributions and probability plots are analyzed. The obtained density distributions have Gaussian distributions and exponential distributions for different values of relaxation times (Gaussian for small values and exponential for large values of relaxation time). It is shown that for middle values of relaxation time the delay distributions have a shape between Gaussian and exponential distributions, which is a result of the different influences of electrical breakdown.

  19. Temporal condensed matter physics in gas-filled photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Tran, Truong X; Marini, Andrea; Belli, Federico; Abdolvand, Amir; Biancalana, Fabio

    2014-01-01

    Raman effect in gases can generate an extremely long-living wave of coherence that can lead to the establishment of an almost perfect periodic variation of the medium refractive index. We show theoretically and numerically that the equations, regulate the pulse propagation in hollow-core photonic crystal fibers filled by Raman-active gas, are exactly identical to a classical problem in quantum condensed matter physics -- but with the role of space and time reversed -- namely an electron in a periodic potential subject to a constant electric field. We are therefore able to infer the existence of Wannier-Stark ladders, Bloch oscillations, and Zener tunneling, phenomena that are normally associated with condensed matter physics only, now realized with purely optical means in the temporal domain.

  20. High pressure gas filled RF cavity beam test at the Fermilab Mucool test area

    Science.gov (United States)

    Freemire, Ben

    With a new generation of lepton colliders being conceived, muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a smaller energy range than a comparable electron collider. This allows a circular collider to be built. As part of the accelerator, it would also be possible to allow the muons to decay to study neutrinos. Because the muon is an unstable particle, a muon beam must be cooled and accelerated within a short amount of time. Muons are generated with a huge phase space, so radio frequency cavities placed in strong magnetic fields are required to bunch, focus, and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary. To successfully operate RF cavities in strong magnetic fields, the cavity can be filled with a high pressure gas in order to mitigate breakdown. The gas has the added benefit of providing cooling for the beam. The electron-ion plasma created in the cavity by the beam absorbs energy and degrades the accelerating electric field of the cavity. As electrons account for the majority of the energy loss in the cavity, their removal in a short time is highly desirable. The addition of an electronegative dopant gas can greatly decrease the lifetime of an electron in the cavity. Measurements in pure hydrogen of the energy consumption of electrons in the cavity range in 10-18 and 10-16 joules per RF cycle per electron. When hydrogen doped with dry air is used, measurements of the power consumption indicate an energy loss range of 10-20 to 10-18 joules per RF cycle per ion, two orders of magnitude improvement over non-doped measurements. The lifetime of electrons in a mixture of hydrogen gas and dry air has been measured from cooling-channel for either machine.

  1. Recompletion of gas filled caverns at underground storage facilities of Verbundnetz Gas AG; Umruestungen gasgefuellter Kavernen auf Untergrundspeichern der Verbundnetz Gas AG

    Energy Technology Data Exchange (ETDEWEB)

    Pischner, M.; Rehmer, K.P. [Untergrundspeicher- und Geotechnologie-Systeme GmbH, Mittenwalde (Germany); Arnold, C. [VNG Verbundnetz Gas AG, Leipzig (Germany)

    2007-11-15

    In 1991 the Verbundnetz Gas AG (VNG AG) has started to modernize outdated installations of the underground gas storage cavern near Bernburg and Bad Lauchstaedt (Germany). On 33 caverns, which were mostly leached during the 70s and 80s of the last century, the old wellheads have been replaced by new ones. In some cases even the production string has been replaced or a new head housing was installed. The reasons and technical suppositions for these measures will be explained. Most of the modifications have been made above gas filled caverns and have been safe despite of the high pressures. The packer-system developed by Untergrundspeicher- und Geotechnologie-Systeme GmbH (UGS GmbH) and VNG AG will be presented. Furthermore the technical procedures are grouped and described. Experiences and development over the years will be outlined. Working above gas filled caverns instead of flooding them before, allowed to reduce the total costs to less than one third. (orig.)

  2. Collapse and rebound of a gas-filled spherical bubble immersed in a diagnostic ultrasonic field.

    Science.gov (United States)

    Aymé-Bellegarda, E J

    1990-08-01

    This work is concerned with the influence of the finite-amplitude distortion of a driving diagnostic ultrasonic field on the collapse and rebound of a gas-filled spherical microbubble, present in the exposed compressible liquid. Such an analysis is especially important since one of the mechanisms for cavitation damage comes from the very large gas pressures generated at bubble collapse and in the subsequent pressure wave formed by bubble rebound. Gilmore's model [F.R. Gilmore, "The growth or collapse of a spherical bubble in a viscous compressible liquid," Hydrodynamics Lab. Rep. No. 26-4, California Institute of Technology, Pasadena, CA (1952)] for bubble dynamics is used to obtain the motion of the bubble interface when subjected to a pulsed diagnostic ultrasonic field of large amplitude. Knowledge of the bubble motion allows one to derive the pressure distribution around the bubble. Numerical results over a range of initial bubble sizes, acoustic pressures, and frequencies relevant to medical use show that the strength of the pressure spikes radiated by the rebounding bubble depends upon (i) the acoustic frequency (f), (ii) the initial bubble size (R0), and (iii) the magnitude of the pressure amplitude of the fundamental (PF) in a Fourier series description of the distorted pulse. As the pressure spikes propagate outward from the bubble wall, their strength is attenuated as the reciprocal of the distance from the center of collapse.

  3. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and Phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  4. Composition and crystalline properties of TiNi thin films prepared by pulsed laser deposition under vacuum and in ambient Ar gas.

    Science.gov (United States)

    Cha, Jeong Ok; Nam, Tae Hyun; Alghusun, Mohammad; Ahn, Jeung Sun

    2012-01-05

    TiNi shape memory alloy thin films were deposited using the pulsed laser deposition under vacuum and in an ambient Ar gas. Our main purpose is to investigate the influences of ambient Ar gas on the composition and the crystallization temperature of TiNi thin films. The deposited films were characterized by energy-dispersive X-ray spectrometry, a surface profiler, and X-ray diffraction at room temperature. In the case of TiNi thin films deposited in an ambient Ar gas, the compositions of the films were found to be very close to the composition of target when the substrate was placed at the shock front. The in-situ crystallization temperature (ca. 400°C) of the TiNi film prepared at the shock front in an ambient Ar gas was found to be lowered by ca. 100°C in comparison with that of a TiNi film prepared under vacuum.

  5. Developments for transactinide chemistry experiments behind the gas-filled separator TASCA

    Energy Technology Data Exchange (ETDEWEB)

    Even, Julia

    2011-12-13

    Topic of this thesis is the development of experiments behind the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) to study the chemical properties of the transactinide elements. In the first part of the thesis, the electrodepositions of short-lived isotopes of ruthenium and osmium on gold electrodes were studied as model experiments for hassium. From literature it is known that the deposition potential of single atoms differs significantly from the potential predicted by the Nernst equation. This shift of the potential depends on the adsorption enthalpy of therndeposited element on the electrode material. If the adsorption on the electrode-material is favoured over the adsorption on a surface made of the same element as the deposited atom, the electrode potential is shifted to higher potentials. This phenomenon is called underpotential deposition. Possibilities to automatize an electro chemistry experiment behind the gas-filled separator were explored for later studies with transactinide elements. The second part of this thesis is about the in-situ synthesis of transition-metal-carbonyl complexes with nuclear reaction products. Fission products of uranium-235 and californium-249 were produced at the TRIGA Mainz reactor and thermalized in a carbon-monoxide containing atmosphere. The formed volatile metal-carbonyl complexes could be transported in a gas-stream. Furthermore, short-lived isotopes of tungsten, rhenium, osmium, and iridium were synthesised at the linear accelerator UNILAC at GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt. The recoiling fusion products were separated from the primary beam and the transfer products in the gas-filled separator TASCA. The fusion products were stopped in the focal plane of TASCA in a recoil transfer chamber. This chamber contained a carbon-monoxide - helium gas mixture. The formed metal-carbonyl complexes could be transported in a gas stream to various experimental setups. All

  6. Design and fabrication of a data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector development

    CERN Document Server

    Sahu, S; Rudra, Sharmili; Biswas, S; Mohanty, B; Sahu, P K

    2015-01-01

    A novel instrument has been developed to monitor and record the ambient pa- rameters such as temperature, atmospheric pressure and relative humidity. These parameters are very essential for understanding the characteristics such as gain of gas filled detectors like Gas Electron Multiplier (GEM) and Multi Wire Propor- tional Counter (MWPC). In this article the details of the design, fabrication and operation processes of the device has been presented.

  7. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, Nigel Oswald [Univ. of California, Berkeley, CA (United States)

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of ~17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, ~200 g/cm3 and ~20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ~350 MJ of energy in optimized power plant scenarios.

  8. Isobar Suppression by Photodetachment in a Gas-Filled RF Quadrupole Ion Guide

    CERN Document Server

    Liu, Yuan; Havener, Aaron; Havener, Charles; Liang, Felix

    2005-01-01

    A novel method is described for selective suppression of isobar contaminants in negative radioactive ion beams. Negative ion beams extracted from an ion source were decelerated to low energies and injected into a gas-filled radio-frequency quadrupole (RFQ) ion guide where the ions were cooled and unwanted ions were selectively removed by non-resonant photodetachment with photons of sufficient energy. Simulation studies show that the laser-ion interaction time in a 40 cm long RFQ ion guide can be on the order of milliseconds, thus, high efficiency photodetachment is possible with commercially available CW lasers. There are a number of adjacent-Z species whose negative ions are such that photodetachment can be used to suppress the unwanted negative ion species while leaving the species of interest intact. Examples of particular interest include suppressing the 56Co- component in a mixed 56Ni- + 56Co- beam and the 17O- component in a mixed 17O- + 17F- beam. In a proof-of-principle experiment a CW Nd:YAG laser at...

  9. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Barboza, N.O.

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of {approximately}17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, {approximately}200 g/cm{sup 3} and {approximately}20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases {approximately}350 MJ of energy in optimized power plant scenarios.

  10. Raman-free nonlinear optical effects in high pressure gas-filled hollow core PCF.

    Science.gov (United States)

    Azhar, M; Wong, G K L; Chang, W; Joly, N Y; Russell, P St J

    2013-02-25

    The effective Kerr nonlinearity of hollow-core kagomé-style photonic crystal fiber (PCF) filled with argon gas increases to ~15% of that of bulk silica glass when the pressure is increased from 1 to 150 bar, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering-absent in noble gases-and having an extremely high optical damage threshold. As a result, detailed and well-controlled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixed-frequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability side-band and a soliton-created dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realization of reconfigurable supercontinuum sources, wavelength convertors and short-pulse laser systems.

  11. The Evolution of the Gold Bubble in NIF Ignition Gas-Filled Hohlraums

    Science.gov (United States)

    Schneider, Marilyn; MacLaren, Steve; Widmann, Klaus; Meezan, Nathan; Hammer, James; Bell, Perry; Benedetti, Robin; Bradley, David; Callahan, Deborah; Dewald, Eduard; Doeppner, Tilo; Hinkel, Denise; Jones, Oggie; Landen, O. L.; Michel, Pierre; Milovich, Jose; Moody, John; Moore, Alastair

    2015-11-01

    At the National Ignition Facility (NIF), the energy from 192 laser beams is converted to an x-ray drive in a gas-filled gold hohlraum. The x-ray drive heats and implodes a fuel capsule. The ViewFactor platform uses a truncated hohlraum to measure the x-ray drive from the capsule point-of-view. This platform also affords excellent diagnostic views of the hohlraum interior, in particular, of the region in which the outer beams deposit their energy (the ``gold bubble'') Time-resolved and time-integrated images in the hard x-ray range (>3 keV) reveal an 8-fold symmetry in the gold bubble. The Au plasma in the bubble from the eight 50 degree quads expands faster than that from the interleaved 44.5 degree quads. The variation in this structure with laser intensity, with pulse shape and cross beam energy transfer, and comparison to models, will be discussed. This work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Collision of an Arched Plasma-Filled Flux Rope with a Target Cloud of Initially Neutral Gas

    Science.gov (United States)

    Wongwaitayakornkul, Pakorn; Bellan, Paul M.

    2015-11-01

    The Caltech solar loop experiment apparatus had been used to create an arched plasma-filled flux rope that expands to collide with a pre-injected initially-neutral gas. We investigated such a situation in two regimes: (i) plasma made by heavy gas impacting a much lighter neutral gas cloud and (ii) a light-gas plasma impacting much heavier neutral gas. The neutral gas became ionized immediately upon impact. In regime (i), multiple shock layers were formed in the target cloud; these magnetized collisionless shocks are relevant to solar physics as such shocks develop ahead of Coronal Mass Ejections and occur in Co-rotating Interaction Regions. In regime (ii), plasma expansion was inhibited. In both cases, fast camera images, magnetic probe measurements, and spectroscopy data will be reported. The analysis of plasma and shock expansion, as well as associated density and temperature changes, will be presented.

  13. Generation Control of ZnO Nanoparticles Using a Coaxial Gas-Flow Pulse Plasma Ar/O2 Plasma

    Directory of Open Access Journals (Sweden)

    Hiroki Shirahata

    2015-01-01

    Full Text Available Generation of ZnO nanoparticles was investigated using a coaxial gas-flow pulse plasma. We studied how zinc atoms, sputtered from a zinc target, reacted with oxygen in a plasma and/or on a substrate to form ZnO nanoparticles when the discharge parameters, such as applied pulse voltage and gas flow rate, were controlled in an O2/Ar plasma. The formation processes were estimated by SEM, TEM, and EDX. We observed many ZnO nanoparticles deposited on Si substrate. The particle yield and size were found to be controlled by changing the experimental parameters. The diameter of the particles was typically 50–200 nm.

  14. The Gas-Filled-Magnet at PRIME Lab: Increased Sensitivity of Cosmogenic Nuclide Measurements

    Science.gov (United States)

    Caffee, M. W.; Granger, D. E.; Woodruff, T. E.

    2015-12-01

    Abstract: Using accelerator mass spectrometry (AMS), radionuclides produced either by cosmic-ray interactions or by nucleogenic means can be measured. Typical isotopic abundance ratios range from 1 x 10-10 to 1 x 10-15. The routinely measured radionuclides are 10Be, 14C, 26Al, 36Cl, and 129I. Be-10, 26Al, and 36Cl have isobaric interferences that cannot be eliminated mass through mass analysis, but dE/dx techniques suppresses these isobars enough to allow successful measurements. There are compromises, the isobar for 26Al, 26Mg, precludes successful measurement of 26Al if AlO- is injected into the accelerator. Mg- doesn't form a stable negative ion so a 26Al measurement requires injection of 26Al-. But the Al- ion is formed inefficiently; secondary ion currents using Al- are ~ 10 times less than an AlO- secondary ion beam. Precision scales with count rate so precise measurement of the 26Al/Al for all but higher ratio samples is difficult. It has long been recognized that a gas-filled-magnet (GFM) could potentially improve the measurement of those radionuclides with intractable isobar interferences. A GFM works on the principle that each element of an isobar pair, e.g. 26Mg and 26Al, has a different average charge state as it traverses a gas (3-4 Torr of N2) contained within the vacuum jacket of a magnet. The magnet steers each species with its own momentum-to-charge ratio on its own distinct radius of curvature. The magnet can be tuned to allow the isotope of interest into a dE/dx detector; most of the isobar doesn't make it into the detector. Using the PRIME Lab GFM we are now able to routinely run 26Al with a precision that is comparable to that obtained with 10Be. We are also using the GFM for routine measurements of 10Be and 36Cl. Although the improvement for these nuclides is not as pronounced as it is for 26Al, the GFM has improved the detection sensitivity for both. Our 10Be background is now ~ 5 x 10-16 and for 36Cl we can now run the source more

  15. High-power gas-discharge excimer ArF, KrCl, KrF and XeCl lasers utilising two-component gas mixtures without a buffer gas

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S [Novosibirsk State University, Novosibirsk (Russian Federation)

    2016-03-31

    Results of an experimental study of the influence of a gas mixture (laser active medium) composition on an output energy and total efficiency of gas-discharge excimer lasers on ArF* (193 nm), KrCl* (222 nm), KrF* (248 nm) and XeCl* (308 nm) molecules operating without a buffer gas are presented. The optimal ratios of gas components (from the viewpoint of a maximum output energy) of an active medium are found, which provide an efficient operation of laser sources. It is experimentally confirmed that for gas-discharge excimer lasers on halogenides of inert gases the presence of a buffer gas in an active medium is not a necessary condition for efficient operation. For the first time, in two-component gas mixtures of repetitively pulsed gas-discharge excimer lasers on electron transitions of excimer molecules ArF*, KrCl*, KrF* and XeCl*, the pulsed energy of laser radiation obtained under pumping by a transverse volume electric discharge in a low-pressure gas mixture without a buffer gas reached up to 170 mJ and a high pulsed output power (of up to 24 MW) was obtained at a FWHM duration of the KrF-laser pulse of 7 ns. The maximal total efficiency obtained in the experiment with two-component gas mixtures of KrF and XeCl lasers was 0.8%. (lasers)

  16. High-power gas-discharge excimer ArF, KrCl, KrF and XeCl lasers utilising two-component gas mixtures without a buffer gas

    Science.gov (United States)

    Razhev, A. M.; Kargapol'tsev, E. S.; Churkin, D. S.

    2016-03-01

    Results of an experimental study of the influence of a gas mixture (laser active medium) composition on an output energy and total efficiency of gas-discharge excimer lasers on ArF* (193 nm), KrCl* (222 nm), KrF* (248 nm) and XeCl* (308 nm) molecules operating without a buffer gas are presented. The optimal ratios of gas components (from the viewpoint of a maximum output energy) of an active medium are found, which provide an efficient operation of laser sources. It is experimentally confirmed that for gas-discharge excimer lasers on halogenides of inert gases the presence of a buffer gas in an active medium is not a necessary condition for efficient operation. For the first time, in two-component gas mixtures of repetitively pulsed gas-discharge excimer lasers on electron transitions of excimer molecules ArF*, KrCl*, KrF* and XeCl*, the pulsed energy of laser radiation obtained under pumping by a transverse volume electric discharge in a low-pressure gas mixture without a buffer gas reached up to 170 mJ and a high pulsed output power (of up to 24 MW) was obtained at a FWHM duration of the KrF-laser pulse of 7 ns. The maximal total efficiency obtained in the experiment with two-component gas mixtures of KrF and XeCl lasers was 0.8%.

  17. Reliability of semiconductor and gas-filled diodes for over-voltage protection exposed to ionizing radiation

    Directory of Open Access Journals (Sweden)

    Stanković Koviljka

    2009-01-01

    Full Text Available The wide-spread use of semiconductor and gas-filled diodes for non-linear over-voltage protection results in a variety of possible working conditions. It is therefore essential to have a thorough insight into their reliability in exploitation environments which imply exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on over-voltage diode characteristics by exposing the diodes to californium-252 combined neutron/gamma radiation field. The irradiation of semiconductor over-voltage diodes causes severe degradation of their protection characteristics. On the other hand, gas-filled over-voltage diodes exhibit a temporal improvement of performance. The results are presented with the accompanying theoretical interpretations of the observed changes in over-voltage diode behaviour, based on the interaction of radiation with materials constituting the diodes.

  18. Soliton self-frequency blue-shift in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Hoelzer, Philipp; Nazarkin, Alexander; Travers, John C; Joly, Nicolas Y; Russell, Philip St J; Biancalana, Fabio

    2011-01-01

    We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency red-shift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range non-local soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between red-shifted, blue-shifted and stabilized solitons can take place in the same fiber.

  19. Theory of Photoionization-Induced Blueshift of Ultrashort Solitons in Gas-Filled Hollow-Core Photonic Crystal Fibers

    Science.gov (United States)

    Saleh, Mohammed F.; Chang, Wonkeun; Hölzer, Philipp; Nazarkin, Alexander; Travers, John C.; Joly, Nicolas Y.; Russell, Philip St. J.; Biancalana, Fabio

    2011-11-01

    We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency redshift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range nonlocal soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between redshifted, blueshifted, and stabilized solitons can take place in the same fiber.

  20. Theory of photoionization-induced blueshift of ultrashort solitons in gas-filled hollow-core photonic crystal fibers.

    Science.gov (United States)

    Saleh, Mohammed F; Chang, Wonkeun; Hölzer, Philipp; Nazarkin, Alexander; Travers, John C; Joly, Nicolas Y; Russell, Philip St J; Biancalana, Fabio

    2011-11-11

    We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency redshift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range nonlocal soliton interactions leading to spectral and temporal soliton clustering. Furthermore, if the core is filled with a Raman-active molecular gas, spectral transformations between redshifted, blueshifted, and stabilized solitons can take place in the same fiber.

  1. Third-Harmonic Generated in EH32 Mode of a Gas-Filled Waveguide by fs Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2007-01-01

    In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in [C.G. Durfee Ⅲ, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Lett. 22 (1997) 1565]. Some possible factors, which produce the contradiction, are discussed briefly.

  2. Detection of fusion residues produced by inverse kinematic reactions using a gas-filled split-pole spectrograph

    CERN Document Server

    Liang, J F; Beene, J R; Bierman, J D; Galindo-Uribarri, A; Gomez-Campo, J D; Gross, C J; Halbert, M L; Harding, T J; McNab, A I; McNeal, S P; Varner, R L; Zhao, K

    1999-01-01

    A focal plane detector has been constructed for detecting fusion residues in a gas-filled Enge split-pole spectrograph. It provides position, timing and energy for particle identification. With a timing channel plate detector in the target chamber, the particle time-of-flight can be measured. This detector system is particularly suitable for studying fusion-evaporation reactions in inverse kinematics. (author)

  3. Hybrid recoil mass analyzer at IUAC – First results using gas-filled mode and future plans

    Indian Academy of Sciences (India)

    N Madhavan; S Nath; T Varughese; J Gehlot; A Jhingan; P Sugathan; A K Sinha; R Singh; K M Varier; M C Radhakrishna; E Prasad; S Kalkal; G Mohanto; J J Das; Rakesh Kumar; R P Singh; S Muralithar; R K Bhowmik; A Roy; Rajesh Kumar; S K Suman; A Mandal; T S Datta; J Chacko; A Choudhury; U G Naik; A J Malyadri; M Archunan; J Zacharias; S Rao; Mukesh Kumar; P Barua; E T Subramanian; K Rani; B P Ajith Kumar; K S Golda

    2010-08-01

    Hybrid recoil mass analyzer (HYRA) is a unique, dual-mode spectrometer designed to carry out nuclear reaction and structure studies in heavy and medium-mass nuclei using gas-filled and vacuum modes, respectively and has the potential to address newer domains in nuclear physics accessible using high energy, heavy-ion beams from superconducting LINAC accelerator (being commissioned) and ECR-based high current injector system (planned) at IUAC. The first stage of HYRA is operational and initial experiments have been carried out using gas-filled mode for the detection of heavy evaporation residues and heavy quasielastic recoils in the direction of primary beam. Excellent primary beam rejection and transmission efficiency (comparable with other gas-filled separators) have been achieved using a smaller focal plane detection system. There are plans to couple HYRA to other detector arrays such as Indian national gamma array (INGA) and 4 spin spectrometer for ER tagged spectroscopic/spin distribution studies and for focal plane decay measurements.

  4. The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions

    Directory of Open Access Journals (Sweden)

    I. S. STAMENKOVIC

    2005-12-01

    Full Text Available Gas holdup was investigated in a gas–liquid and gas–liquid-solid reciprocating plate column (RPC under various operation conditions. Aqueous carboxymethylcellulose (sodium salt, CMC solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas plase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the liquid phase. The gas holdup increased with increasing vibration intensity and superficial gas velocity in both the two- and three-phase system. With increasing concentration of the CMC PP 50 solution (Newtonian fluid, the gas holdup decreased, because the coalescence of the bubbles was favored by the higher liquid viscosity. In the case of the CMC PP 200 solutions (non-Newtonian liquids, the gas holdup depends on the combined influence of the rheological properties of the liquid phase, the vibration intensity and the superficial gas velocity. The gas holdup in the three-phase systems was greater than that in the two-phase ones under the same operating conditions. Increasing the solids content has little influence on the gas holdup. The gas holdup was correlated with the power consumption (either the time-averaged or total power consuption and the superficial gas velocity.

  5. Annual and transient signatures of gas exchange and transport in the Castañar de Ibor cave (Spain

    Directory of Open Access Journals (Sweden)

    Fernandez-Cortes A.

    2009-07-01

    Full Text Available The large microclimatic stability is a basic characteristic of the subterranean karst systems and causes a high sensitivity to changesin environmental conditions. High-accuracy monitoring of Castañar de Ibor cave (Spain determined the temporal evolution of theaerodynamic processes and ventilation rate by tracking CO2 and 222Rn levels over a twelve-month period. This cave is characterizedby a very stable microclimate, with high and relatively constant radon content (the mean value is 32200 Bq/m3, roughly, and thestandard deviation is 7600 Bq/m3 and a moderate and quite stable CO2 concentration (the mean value is 3730 ppm and the standarddeviation is 250 ppm. Beside the general patterns of cave microclimate throughout an annual cycle, some particular microclimaticprocesses are described with regard to the gas exchange between the cave and the outside atmosphere. There is a complexmicroclimatic functional relationship between the meteorological and cave microclimate conditions and the diffusion and flow of tracergases from the fractures and the pore system of soil and host rock to cave atmosphere. Transient variations of tracer gas on cave airare controlled by natural barometric fluxes and anthropogenic forced ventilation due to uncontrolled opening of cave entrance. Theshort-term fluctuations of gas levels on cave air reveal distinct patterns during the exhalation process of theses gases from the netof fissures and pores to the cave atmosphere, depending on the isolation effect of soil and host rock.

  6. Efficient spectral broadening in the 100-W average power regime using gas-filled kagome HC-PCF and pulse compression.

    Science.gov (United States)

    Emaury, Florian; Saraceno, Clara J; Debord, Benoit; Ghosh, Debashri; Diebold, Andreas; Gèrôme, Frederic; Südmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2014-12-15

    We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core kagome hollow-core photonic crystal fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a kagome HC-PCF containing 13 bar of static argon gas. Subsequent compression tests performed using 8.4% of the full available power resulted in a pulse duration as short as 88 fs using the spectrally broadened output from the fiber. Compressing the full transmitted power through the fiber (118 W) could lead to a compressed output of >100  W of average power and >100  MW of peak power with an average power compression efficiency of 88%. This simple laser system with only one ultrafast laser oscillator and a simple single-pass fiber pulse compressor, generating both high peak power >100  MW and sub-100-fs pulses at megahertz repetition rate, is very interesting for many applications such as high harmonic generation and attosecond science with improved signal-to-noise performance.

  7. Chronology and shock history of the Bencubbin meteorite: A nitrogen, noble gas, and Ar-Ar investigation of silicates, metal and fluid inclusions

    Science.gov (United States)

    Marty, Bernard; Kelley, Simon; Turner, Grenville

    2010-11-01

    We have investigated the distribution and isotopic composition of nitrogen and noble gases, and the Ar-Ar chronology of the Bencubbin meteorite. Gases were extracted from different lithologies by both stepwise heating and vacuum crushing. Significant amounts of gases were found to be trapped within vesicles present in silicate clasts. Results indicate a global redistribution of volatile elements during a shock event caused by an impactor that collided with a planetary regolith. A transient atmosphere was created that interacted with partially or totally melted silicates and metal clasts. This atmosphere contained 15N-rich nitrogen with a pressure ⩾3 × 10 5 hPa, noble gases, and probably, although not analyzed here, other volatile species. Nitrogen and noble gases were re-distributed among bubbles, metal, and partly or totally melted silicates, according to their partition coefficients among these different phases. The occurrence of N 2 trapped in vesicles and dissolved in silicates indicates that the oxygen fugacity ( fO2) was greater than the iron-wüstite buffer during the shock event. Ar-Ar dating of Bencubbin glass gives an age of 4.20 ± 0.05 Ga, which probably dates this impact event. The cosmic-ray exposure age is estimated at ˜40 Ma with two different methods. Noble gases present isotopic signatures similar to those of "phase Q" (the major host of noble gases trapped in chondrites) but elemental patterns enriched in light noble gases (He, Ne and Ar) relative to Kr and Xe, normalized to the phase Q composition. Nitrogen isotopic data together with 40Ar/ 36Ar ratios indicate mixing between a 15N-rich component (δ 15N = +1000‰), terrestrial N, and an isotopically normal, chondritic N. Bencubbin and related 15N-rich meteorites of the CR clan do not show stable isotope (H and C) anomalies, precluding contribution of a nucleosynthetic component as the source of 15N enrichments. This leaves two possibilities, trapping of an ancient, highly fractionated

  8. Fabrication of cm scale buckypapers of horizontally aligned multiwalled carbon nanotubes highly filled with Fe3C: the key roles of Cl and Ar-flow rates.

    Science.gov (United States)

    Boi, Filippo S; Guo, Jian; Wang, Shanling; He, Yi; Xiang, Gang; Zhang, Xi; Baxendale, Mark

    2016-03-18

    A key challenge in the fabrication of ferromagnetically filled carbon-nanotube buckypapers in the presence of Cl-radicals is the achievement of a preferential horizontal nanotube-alignment. We show that a horizontal-alignment can be achieved by tuning two main CVD parameters for a fixed dichlorobenzene concentration: the precursor-evaporation temperature and the flow rate.

  9. Resonant third harmonic generation of KrF laser in Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, R. [Department of Experimental Physics, University of Szeged, 6720 Szeged, Dóm tér 9 (Hungary); Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00–908 Warsaw (Poland); Barna, A. [Department of Experimental Physics, University of Szeged, 6720 Szeged, Dóm tér 9 (Hungary); Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, EURATOM Association HAS, 1121 Budapest, XII. Konkoly Thege Miklós út 29-33 (Hungary); Suta, T.; Földes, I. B. [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, EURATOM Association HAS, 1121 Budapest, XII. Konkoly Thege Miklós út 29-33 (Hungary); Bohus, J.; Szatmári, S. [Department of Experimental Physics, University of Szeged, 6720 Szeged, Dóm tér 9 (Hungary); Mikołajczyk, J.; Bartnik, A.; Fiedorowicz, H. [Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00–908 Warsaw (Poland); Verona, C. [Department of Mechanical Engineering, University “Tor Vergata”, Via Orazio Raimondo, 18–00173, Rome (Italy); Verona Rinati, G. [Department of Industrial Engineering, University “Tor Vergata”, Via Orazio Raimondo, 18–00173, Rome (Italy); Margarone, D. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, 182 21 Prague (Czech Republic); Nowak, T. [Institute of Nuclear Physics, PAN, E. Radzikowskiego 152, 31–342 Cracow (Poland); and others

    2014-12-15

    Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence.

  10. NON-INTRUSIVE SENSOR FOR GAS FILL VERIFICATION OF INSULATED GLASS WINDOWS

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Freedman; Paul L. Kebabian; Richard R. Romano; James Woodroffe

    2003-10-01

    A sensor capable of measuring the amount of oxygen (an unwanted component that is only present because of improper filling or seal failure) within an argon-filled insulated glass window has been designed, built and successfully tested. It operates by using the optical absorption of oxygen in the atmospheric A-band centered at 762 nm. Light emitted by an argon-filled surface glow discharge lamp is Zeeman-tuned on and off an oxygen absorption line using an AC-modulated electromagnet. In the presence of oxygen, the change in the measured intensity of the lamp, obtained using standard demodulation techniques, is proportional to the oxygen column density. Measurements using an industry-standard insulated glass window indicate that the sensor can measure the amount of oxygen in a nominally argon-filled IG window (with a window gap of 10 mm) with a precision of 0.50% oxygen using a 16 second integration time. This level of precision is well within the limits required by the IG window manufacturing industry for proper monitoring of newly manufactured window units.

  11. A comparison between micro hollow cathode discharges and atmospheric pressure plasma jets in Ar/O2 gas mixtures

    Science.gov (United States)

    Lazzaroni, C.; Chabert, P.

    2016-12-01

    Using global models, micro hollow cathode discharges (MHCDs) are compared to radiofrequency atmospheric pressure plasma jets (APPJs) in terms of reactive oxygen species (ROS) production. Ar/O2 gas mixtures are investigated, typically with a small percentage of oxygen in argon. The same chemical reaction set, involving 17 species and 128 chemical reactions in the gas phase, is used for both devices, operated in the typical geometries previously published; the APPJ is driven by a radiofrequency voltage across a 1 mm gap, at atmospheric pressure, while the MHCD is driven by a DC voltage source, at 100 Torr and in a 400 μm hole. The MHCD may be operated either in the self-pulsing or in the normal (stationary) regime, depending on the driving voltage. The comparison shows that in both regimes, the MHCD produces larger amounts of \\text{O}2\\ast , while the APPJ produces predominantly reactive oxygen ground state species, \\text{O} and {{\\text{O}}3} . These large differences in ROS composition are mostly due to the higher plasma density produced in the MHCD. The difference in operating pressure is a second order effect.

  12. Effects of void size and gas content on electrical breakdown in lightweight, mechanically compliant, void-filled dielectrics

    Science.gov (United States)

    Anderson, R. A.; Lagasse, R. R.; Russick, E. M.; Schroeder, J. L.

    2002-03-01

    Dielectric potting materials (encapsulants) are used to prevent air breakdown in high-voltage electrical devices. We report breakdown strengths in void-filled encapsulants, stressed with unipolar voltage pulses of the order of 10 μs duration. High strengths, on the order of 100 kV mm-1, are measured under these test conditions. The materials studied include low-density open celled gel-derived foams with cell sizes of 4 μm or less, closed celled CO2-blown polystyrene and urethane foams, and epoxies containing 48 vol % of hollow glass microballoon (GMB) fillers. These last specimens varied the void gas (N2 or SO2) and also the void diameters (tens to hundreds of μm). Our measurements are thought to be directly sensitive to the rate of field-induced ionization events in the void gas; however, the breakdown strengths of the materials tested appeared to vary in direct proportion with the conventional Paschen-law gas-discharge inception threshold, the electric stress at which gas-ionization avalanches become possible. The GMB-epoxy specimens displayed this type of dependence of breakdown strength on the void-gas density and void size, but the measurements were an order of magnitude above the conventional predictions. Small-celled foams also showed increased breakdown strengths with decreased cell size, although their irregular void geometry prevented a direct comparison with the more uniformly structured microballoon-filled encapsulants. The experimental observations are consistent with a breakdown mechanism in which the discharge of a few voids can launch a full breakdown in the composite material.

  13. Soliton self-frequency blue-shift in gas-filled hollow-core photonic crystal fibers

    OpenAIRE

    2011-01-01

    We show theoretically that the photoionization process in a hollow-core photonic crystal fiber filled with a Raman-inactive noble gas leads to a constant acceleration of solitons in the time domain with a continuous shift to higher frequencies, limited only by ionization loss. This phenomenon is opposite to the well-known Raman self-frequency red-shift of solitons in solid-core glass fibers. We also predict the existence of unconventional long-range non-local soliton interactions leading to s...

  14. Tunable vacuum-UV to visible ultrafast pulse source based on gas-filled Kagome-PCF.

    Science.gov (United States)

    Mak, Ka Fai; Travers, John C; Hölzer, Philipp; Joly, Nicolas Y; Russell, Philip St J

    2013-05-06

    An efficient and tunable 176-550 nm source based on the emission of resonant dispersive radiation from ultrafast solitons at 800 nm is demonstrated in a gas-filled hollow-core photonic crystal fiber (PCF). By careful optimization and appropriate choice of gas, informed by detailed numerical simulations, we show that bright, high quality, localized bands of UV light (relative widths of a few percent) can be generated at all wavelengths across this range. Pulse energies of more than 75 nJ in the deep-UV, with relative bandwidths of ~3%, are generated from pump pulses of a few μJ. Excellent agreement is obtained between numerical and experimental results. The effects of positive and negative axial pressure gradients are also experimentally studied, and the coherence of the deep-UV dispersive wave radiation numerically investigated.

  15. Surface modification of graphite-encapsulated iron nanoparticles by RF excited Ar/NH3 gas mixture plasma and their application to Escherichia coli capture

    Science.gov (United States)

    Viswan, Anchu; Chou, Han; Sugiura, Kuniaki; Nagatsu, Masaaki

    2016-09-01

    Graphite-encapsulated iron nanoparticles with an average diameter of 20 nm were synthesized using the DC arc discharge method. For biomedical application, the nanoparticles were functionalized with amino groups using an inductively coupled radio-frequency (RF) plasma. The Ar, NH3, and Ar/NH3 plasmas that were used for functionalization were diagnosed using optical emission spectroscopy, confirming the presence of the required elements. The best conditions for functionalization were optimized by changing various parameters. The pretreatment time with Ar plasma was varied from 0 to 12.5 min, the post-treatment time from 30 s to 3 min. The dependence of the RF power and the gas mixture ratio of Ar/NH3 on the amino group population was also analyzed. From Raman spectroscopy, x-ray photoelectron spectroscopy, and determination of absolute number of amino groups through chemical derivatization, it was found that 5 min of Ar pretreatment and 6%NH3/94%Ar plasma post-treatment for 3 min with an RF power of 80 W gives the best result of about 5  ×  104 amino groups per particle. The nanoparticles that were amino functionalized under optimized conditions and immobilized with an Escherichia coli (E.coli) antibody on their surface were incubated with E.coli bacteria to determine the efficiency of collection by direct culture assay.

  16. Gas-Filled Hollow Core Fiber Lasers Based on Population Inversion

    Science.gov (United States)

    2013-12-05

    levels of C2H2 with the pump ( optical parametric oscillator in the telecom C band) and observed lasing transitions. The fiber ends were housed in...FA9550-10-1-0515 FA9550-10-1-0515 AFOSR unlimited Hollow-core Optical Fiber Gas LASer (HOFGLAS) have been created, and explored in pulsed mode with...were created. HOFGLAS, Optically -pumped gas lasers, photonic crystal fiber , microstructured fiber , hollow-core fiber , mid-IR lasers, IR lasers, fiber

  17. Strong Raman-induced non-instantaneous soliton interactions in gas-filled photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Marini, Andrea; Biancalana, Fabio

    2015-01-01

    We have developed an analytical model based on the perturbation theory in order to study the optical propagation of two successive intense solitons in hollow-core photonic crystal fibers filled with Raman-active gases. Based on the time delay between the two solitons, we have found that the trailing soliton dynamics can experience unusual nonlinear phenomena such as spectral and temporal soliton oscillations and transport towards the leading soliton. The overall dynamics can lead to a spatiotemporal modulation of the refractive index with a uniform temporal period and a uniform or chirped spatial period.

  18. Theoretical prediction of new noble-gas molecules FNgBNR (Ng = Ar, Kr, and Xe; R = H, CH3, CCH, CHCH2, F, and OH).

    Science.gov (United States)

    Chen, Jien-Lian; Yang, Chang-Yu; Lin, Hsiao-Jing; Hu, Wei-Ping

    2013-06-28

    We have computationally predicted a new class of stable noble-gas molecules FNgBNR (Ng = Ar, Kr, Xe; R = H, CH3, CCH, CHCH2, F, and OH). The FNgBNR were found to have compact structures with F-Ng bond lengths of 1.9-2.2 Å and Ng-B bond lengths of ~1.8 Å. The endoergic three-body dissociation energies of FNgBNH to F + Ng + BNH were calculated to be 12.8, 31.7, and 63.9 kcal mol(-1), for Ng = Ar, Kr, and Xe, respectively at the CCSD(T)/CBS level. The energy barriers of the exoergic two-body dissociation to Ng + FBNH were calculated to be 16.1, 24.0, and 33.2 kcal mol(-1) for Ng = Ar, Kr, and Xe, respectively. Our results showed that the dissociation energetics is relatively insensitive to the identities of the terminal R groups. The current study suggested that a wide variety of noble-gas containing molecules with different types of R groups can be thermally stable at low temperature, and the number of potentially stable noble-gas containing molecules would thus increase very significantly. It is expected some of the FNgBNR molecules could be identified in future experiments under cryogenic conditions in noble-gas matrices or in the gas phase.

  19. Generation of the organo-rare gas dications HCCRg2+ (Rg = Ar and Kr) in the reaction of acetylene dications with rare gases.

    Science.gov (United States)

    Ascenzi, Daniela; Tosi, Paolo; Roithová, Jana; Ricketts, Claire L; Schröder, Detlef; Lockyear, Jessica F; Parkes, Michael A; Price, Stephen D

    2008-12-21

    Using doubly ionized acetylene as a superelectrophilic reagent, the new rare-gas compounds HCCAr2+ and HCCKr2+ have been prepared for the first time in hyperthermal collisions of mass-selected C2H2(2+) with neutral rare gases (Rg). However, electron transfer from the rare gas to the acetylene dication as well as proton transfer from C2H2(2+) to the rare gas efficiently compete with formation of HCCRg2+. The computational investigations show that the formation of HCCRg2+ from acetylene dication is endothermic with Rg = He, Ne, Ar and Kr and only weakly exothermic with Xe. These energetic factors, as well as the pronounced competition with the other reactive channels help to explain why HCCRg2+ is only observed with Rg = Ar and Kr.

  20. Collision Experiment of an Arched Plasma-Filled Flux Rope and a Target Cloud of Initially Neutral Gas

    Science.gov (United States)

    Wongwaitayakornkul, Pakorn; Bellan, Paul; Li, Hui; Li, Shengtai

    2016-10-01

    Shocks occur in the co-rotating interaction regions just beyond the solar corona, in the corona during CME events, and when the solar wind impacts Earth's magnetosphere. The Caltech solar loop experiment investigates shock physics by creating an arched plasma-filled flux rope that expands to collide with a pre-injected, initially-neutral gas. We focus the investigation on the situation of a heavy-gas plasma (Argon) impacting a much lighter neutral gas cloud (Hydrogen). The neutral gas target cloud ionizes immediately upon being impacted and plasma-induced shock waves propagate in the target cloud away from the impact region. Analysis of data from magnetic probes, Langmuir probes, a fast camera, and spectroscopic measurements will be presented. The measurements suggest that a thin, compressed, ionized layer of hydrogen is formed just downstream of the Argon plasma loop and that thin, supersonic shocks form further downstream and propagate obliquely away from the plasma loop. Numerical simulation of an ideal MHD plasma is underway to enable comparison of the measurements with the predictions of MHD theory.

  1. Gas-filled parasymphyseal pubic cyst associated with degenerative joint disease

    Energy Technology Data Exchange (ETDEWEB)

    Martel, J.P.; Spouge, A.R. [London Health Science Centre, Diagnostic Imaging University Hospital, London, ON (Canada)

    2007-06-15

    Parasymphyseal cysts are a rare and poorly understood entity. This case report describes a gas-containing parasymphyseal cystic lesion associated with degenerative change and vacuum phenomenon in the pubic symphysis. The mass was discovered incidentally in a 72-year-old asymptomatic male who underwent a transrectal ultrasound-guided biopsy of the prostate and the nature of the lesion was confirmed on magnetic resonance imaging (MRI) and computed tomography (CT). We hypothesize that the gas within the parasymphyseal cystic mass arose from a vacuum phenomenon in the pubic symphysis, with subsequent extrusion of gas from the joint into the cyst itself. It is important for radiologists to be aware of the existence of this entity to avoid unnecessary surgery for patients. (orig.)

  2. High-Temperature Corrosion of AlCrSiN Film in Ar-1%SO2 Gas

    Directory of Open Access Journals (Sweden)

    Poonam Yadav

    2017-03-01

    Full Text Available AlCrSiN film with a composition of 29.1Al-17.1Cr-2.1Si-51.7N in at. % was deposited on a steel substrate by cathodic arc ion plating at a thickness of 1.8 μm. It consisted of nanocrystalline hcp-AlN and fcc-CrN, where a small amount of Si was dissolved. Corrosion tests were carried out at 800 °C for 5–200 h in Ar-1%SO2 gas. The major corrosion reaction was oxidation owing to the high oxygen affinity of Al and Cr in the film. The formed oxide scale consisted primarily of (Al,Cr2O3, within which Fe, Si, and S were dissolved. Even after corrosion for 200 h, the thickness of the scale was about 0.7–1.2 μm, indicating that the film had good corrosion resistance in the SO2-containing atmosphere.

  3. Laser frequency standards based on gas-filled hollow-core fibres

    DEFF Research Database (Denmark)

    Triches, Marco

    ,since the advent of the photonic crystal fiber technology, many studies have been performed using various hollow-core fibers used as vapor cells. This hollow-core fiber approach is also meeting the needs of the remote sensing applications, which require size and weight reductions with respect to the conventional......-air Raman scattering, eliminating the remaining obstacle for the implementation of the technology in the laser machining industry. This thesis presents the development of a compact fiber-based optical frequency standard using acetylene-filled hollow-core fibers. The study focuses both on the technical...... within precision spectroscopy with the scope of developing a fiber-based, portable optical frequency standard in the telecommunication band. Nowadays, portable optical frequency standards are important not only in metrology and telecommunication industry but also for remote sensing applications. Since...

  4. Study of x-rays produced from debris-free sources with Ar, Kr and Kr/Ar mixture linear gas jets irradiated by UNR Leopard laser beam with fs and ns pulse duration

    Science.gov (United States)

    Kantsyrev, V. L.; Schultz, K. A.; Shlyaptseva, V. V.; Safronova, A. S.; Shrestha, I. K.; Petrov, G. M.; Moschella, J. J.; Petkov, E. E.; Stafford, A.; Cooper, M. C.; Weller, M. E.; Cline, W.; Wiewior, P.; Chalyy, O.

    2016-06-01

    Experiments of x-ray emission from Ar, Kr, and Ar/Kr gas jet mixture were performed at the UNR Leopard Laser Facility operated with 350 fs pulses at laser intensity of 2 × 1019 W/cm2 and 0.8 ns pulses at an intensity of 1016 W/cm2. Debris free x-ray source with supersonic linear nozzle generated clusters/monomer jet with an average density of ≥1019 cm-3 was compared to cylindrical tube subsonic nozzle, which produced only monomer jet with average density 1.5-2 times higher. The linear (elongated) cluster/gas jet provides the capability to study x-ray yield anisotropy and laser beam self-focusing with plasma channel formation that are interconnecting with efficient x-ray generation. Diagnostics include x-ray diodes, pinhole cameras and spectrometers. It was observed that the emission in the 1-9 keV spectral region was strongly anisotropic depending on the directions of laser beam polarization for sub-ps laser pulse and supersonic linear jet. The energy yield in the 1-3 keV region produced by a linear nozzle was an order of magnitude higher than from a tube nozzle. Non-LTE models and 3D molecular dynamic simulations of Ar and Kr clusters irradiated by sub-ps laser pulses have been implemented to analyze obtained data. A potential evidence of electron beam generation in jets' plasma was discussed. Note that the described debris-free gas-puff x-ray source can generate x-ray pulses in a high repetition regime. This is a great advantage compared to solid laser targets.

  5. Ars disyecta Ars disyecta

    Directory of Open Access Journals (Sweden)

    Alejandra Castillo

    2012-07-01

    Full Text Available Bajo la nominación Ars Disyecta se busca exponer el vínculo entre artes visuales, feminismo y metamorfosis. Las prácticas artísticas feministas aquí presentadas se proponen perturbar el espacio metafórico heredado de la diferencia sexual (pensemos, por ejemplo, en las palabras engendramiento, matriz, vida, compenetración o invaginamiento. En este sentido, la nominación Ars disyecta pone en escena un conjunto de prácticas e intervenciones que intentan interrumpir la matriz de la diferencia, desestabilizando lo femenino desde aquellas figuras que se resisten a la lógica de la totalidad y de un tiempo propio. Buscando seguir la huella de un arte disyecto es que interrogaré en este ensayo aquellas autorías feministas que en el arte contemporáneo trafican con las huellas del contagio, la mutación y la alteridad.This article aims to present the relation between visual arts, feminism I and metamorphosis. The feminist artistic practices portrayed in this article attempt to question categories inherited from the metaphor of sexual difference such as engendering, matrix and life. From this perspective, Ars disyecta will establish a set of artistic practices and interventions that intend to interrupt the proper idea of «feminine difference». Following this line of argument, I will discuss in this article a few contemporary feminist works of art that could be defined by words such as contagious, mutation and otherness.

  6. High-performance, non-CFC-based thermal insulation: Gas filled panels

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, B.T.; Arasteh, D.; Selkowitz, S.

    1992-04-01

    Because of the forthcoming phase-out of CFCs and to comply with the more stringent building and appliance energy-use standards, researchers in industry and in the public sector are pursuing the development of non-CFC-based, high-performance insulation materials. This report describes the results of research and development of one alternative insulation material: highly insulating GFPs. GFPs insulate in two ways: by using a gas barrier envelope to encapsulate a low-thermal-conductivity gas or gas mixture (at atmospheric pressure), and by using low-emissivity baffles to effectively eliminate convective and radiative heat transfer. This approach has been used successfully to produce superinsulated windows. Unlike foams or fibrous insulations, GFPs are not a homogeneous material but rather an assembly of specialized components. The wide range of potential applications of GFPs (appliances, manufactured housing, site-built buildings, refrigerated transport, and so on) leads to several alternative embodiments. While the materials used for prototype GFPs are commercially available, further development of components may be necessary for commercial products. With the exception of a description of the panels that were independently tested, specific information concerning panel designs and materials is omitted for patent reasons; this material is the subject of a patent application by Lawrence Berkeley Laboratory.

  7. Fabrication and testing of gas-filled targets for large-scale plasma experiments on nova

    Energy Technology Data Exchange (ETDEWEB)

    Stone, G.F.; Rivers, C.J.; Spragge, M.R.; Wallace, R.J.

    1996-06-01

    The proposed next-generation ICF facility, the National Ignition Facility (NIF) is designed to produce energy gain from x-ray heated {open_quotes}indirect-drive{close_quotes} fuel capsules. For indirect-drive targets, laser light heats the inside of the Au hohlraum wall and produces x rays which in turn heat and implode the capsule to produce fusion conditions in the fuel. Unlike Nova targets, in NIF-scale targets laser light will propagate through several millimeters of gas, producing a plasma, before impinging upon the Au hohlraum wall. The purpose of the gas-produced plasma is to provide sufficient pressure to keep the radiating Au surface from expanding excessively into the hohlraum cavity. Excessive expansion of the Au wall interacts with the laser pulse and degrades the drive symmetry of the capsule implosion. The authors have begun an experimental campaign on the Nova laser to study the effect of hohlraum gas on both laser-plasma interaction and implosion symmetry. In their current NIF target design, the calculated plasma electron temperature is T{sub e} {approx} 3 keV and the electron density is N{sub e} {approx} 10{sup 21}cm{sup {minus}3}.

  8. Mutual Neutralization of Atomic Rare-Gas Cations (Ne+, Ar+, Kr+, Xe+) with Atomic Halide Anions (Cl-, Br-, I-)

    Science.gov (United States)

    2015-01-07

    but mixing prior to entering the flow tube through a single inlet, to yield a mixture of Rg+ cations. Experiments were conducted in Ar+/Ne+, Ar+/Xe...Johnsen and M. A. Biondi, Phys. Rev. A 20, 87–97 (1979). 25W. Lindinger, Phys. Scr . T3, 115–119 (1983). 26R. E. Olson, J. Chem. Phys. 56, 2979–2984

  9. Spectroscopic and modeling investigations of the gas-phase chemistry and composition in microwave plasma activated B2H6/Ar/H2 mixtures.

    Science.gov (United States)

    Ma, Jie; Richley, James C; Davies, David R W; Cheesman, Andrew; Ashfold, Michael N R; Mankelevich, Yuri A

    2010-02-25

    This paper describes a three-pronged study of microwave (MW) activated B(2)H(6)/Ar/H(2) plasmas as a precursor to diagnosis of the B(2)H(6)/CH(4)/Ar/H(2) plasmas used for the chemical vapor deposition of B-doped diamond. Absolute column densities of B atoms and BH radicals have been determined by cavity ring-down spectroscopy as a function of height (z) above a molybdenum substrate and of the plasma process conditions (B(2)H(6) and Ar partial pressures, total pressure, and supplied MW power). Optical emission spectroscopy has been used to explore variations in the relative densities of electronically excited BH, H, and H(2) species as a function of the same process conditions and of time after introducing B(2)H(6) into a pre-existing Ar/H(2) plasma. The experimental measurements are complemented by extensive 2-D(r, z) modeling of the plasma chemistry, which results in refinements to the existing B/H chemistry and thermochemistry and demonstrates the potentially substantial loss of gas-phase BH(x) species through reaction with trace quantities of air/O(2) in the process gas mixture and heterogeneous processes occurring at the reactor wall.

  10. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

    DEFF Research Database (Denmark)

    Triches, Marco; Brusch, Anders; Hald, Jan

    2015-01-01

    A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal...... the hollow-core fiber with easy light coupling, showing negligible pressure increase over two months. The locked laser shows a fractional frequency instability below 8 × 10−12 for an averaging time up to 104 s. The lock-point repeatability over one month is 2.6 × 10−11, corresponding to a standard deviation...

  11. Effect of a transverse magnetic field on the generation of electron beams in the gas-filled diode

    Science.gov (United States)

    Baksht, E. H.; Burachenko, A. G.; Erofeev, M. V.; Kostyrya, I. D.; Lomaev, M. I.; Rybka, D. V.; Tarasenko, V. F.

    2008-06-01

    The effect of a transverse magnetic field (0.080 and 0.016 T) on generation of an electron beam in the gas-filled diode is experimentally investigated. It is shown that, at voltage U = 25 kV across the diode and a low helium pressure (45 Torr), the transverse magnetic field influences the beam current amplitude behind a foil and its distribution over the foil cross section. At elevated pressures and under the conditions of ultrashort avalanche electron beam formation in helium, nitrogen, and air, the transverse magnetic field (0.080 and 0.016 T) has a minor effect on the amplitude and duration of the beam behind the foil. It is established that, when the voltage of the pulse generator reaches several hundreds of kilovolts, some runaway electrons (including the electrons from the discharge plasma near the cathode) are incident on the side walls of the diode.

  12. Magnetic discharge accelerating diode for the gas-filled pulsed neutron generators based on inertial confinement of ions

    Science.gov (United States)

    Kozlovskij, K. I.; Shikanov, A. E.; Vovchenko, E. D.; Shatokhin, V. L.; Isaev, A. A.; Martynenko, A. S.

    2016-09-01

    The paper deals with magnetic discharge diode module with inertial electrostatic ions confinement for the gas-filled pulsed neutron generators. The basis of the design is geometry with the central hollow cathode surrounded by the outer cylindrical anode and electrodes made of permanent magnets. The induction magnitude about 0.1-0.4 T in the central region of the discharge volume ensures the confinement of electrons in the space of hollow (virtual) cathode and leads to space charge compensation of accelerated ions in the centre. The research results of different excitation modes in pulsed high-voltage discharge are presented. The stable form of the volume discharge preserveing the shape and amplitude of the pulse current in the pressure range of 10-3-10-1 Torr and at the accelerating voltage up to 200 kV was observed.

  13. FIssion Product Prompt γ-ray spectrometer: Development of an instrumented gas-filled magnetic spectrometer at the ILL

    Science.gov (United States)

    Blanc, A.; Chebboubi, A.; Faust, H.; Jentschel, M.; Kessedjian, G.; Köster, U.; Materna, T.; Panebianco, S.; Sage, C.; Urban, W.

    2013-12-01

    Accurate thermal neutron-induced fission data are important for applications in reactor physics as well as for fundamental nuclear physics. FIPPS is the new FIssion Product Prompt γ-ray Spectrometer being developed at the Institut Laue Langevin for neutron-induced fission studies. FIPPS is based on the combination of a large Germanium detector array surrounding a fission target, a Time-Of-Flight detector and a Gas-Filled Magnet (GFM) to identify mass, nuclear charge and kinetic energy of one of the fission fragments. The GFM will be instrumented with a Time-Projection Chamber (TPC) for individual 3D tracking of the fragments. A conceptual design study of the new spectrometer is presented.

  14. Effect of the gas temperature and pressure on the nucleation time of particles in low pressure Ar-C2H2 rf plasmas

    Science.gov (United States)

    Lin, Jiashu; Henault, Marie; Orazbayev, Sagi; Boufendi, Laïa; Takahashi, Kazuo; Al Farabi Kazakh National University Collaboration; Kyoto Institute Of Technology Team; Gremi Team

    2016-09-01

    Particle formation in low pressure plasmas is a 3-step process. The first one corresponds to the nucleation and growth of nano-crystallites by ion-molecular reactions, the agglomeration phase to form large particles, and the growth by radical deposition on the particle surface. The nucleation phase was demonstrated to be sensitive to gas temperature and pressure. In this work, time of nucleation phase of particles formation in low pressure cold rf C2H2/Ar plasmas studied by varying gas temperature from 265 K to 375 K, gas pressure from 0.4 mbar to 0.8 mbar and rf power from 6 W to 20 W. The ratio of C2H2/Ar is fixed to 2/98 in terms of pressure. Several previous works reported that particle formation takes a few sec at room temperature in C2 H2 plasmas and the time is much shorter than 0.1 s in SiH4 plasmas. Time evolution of self-bias voltage was mainly used to determine nucleation time. The self-bias voltage was modified by phase transition between the steps from nucleation to coagulation. The experimental results showed that the nucleation time increased with gas temperature, decreased with gas pressure and discharge power. At constant gas pressure of 0.4 mbar and discharge power of 6 W, for example, the nucleation time increased from 5 sec to 30 sec with increas

  15. Ar/O{sub 2} gas pressure dependence of atomic concentration of zirconia prepared by zirconium pulse arc PBII and D

    Energy Technology Data Exchange (ETDEWEB)

    Yukimura, Ken [Department of Electrical Engineering, Doshisha University, 1-3 Tatara-Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan)]. E-mail: kyukimur@mail.doshisha.ac.jp; Yoshinaga, Hiroaki [Department of Electrical Engineering, Doshisha University, 1-3 Tatara-Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Ohtsu, Yasunori [Department of Electrical and Electronic Engineering, Saga University, Honjo-machi1, Saga 840-8502 (Japan); Fujita, Hiroharu [Department of Electrical and Electronic Engineering, Saga University, Honjo-machi1, Saga 840-8502 (Japan); Nakamura, Keiji [Department of Electrical Engineering, College of Engineering, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501 (Japan); Ma Xinxin [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2006-01-15

    Zirconium oxide films were prepared by plasma-based ion implantation and deposition (PBII and D), where a zirconium pulse arc discharge was generated in O{sub 2}/Ar gas mixture. The plasma was maintained for approximately 3 ms, and the ion current at the substrate was detected in a time range from 1 to 10 ms after the arc initiation. At O{sub 2}/Ar pressures of 2.6-3.0 Pa, a stoichiometric film was obtained, while at a pressure lower than 2.2 Pa, the film also contained ZrO {sub x} (x < 2) phase as well as ZrO{sub 2} phase. In the absence of argon gas, the plasma became unstable, which resulted in shortage of zirconium ions in the plasma, and hence, a stoichiometric condition was not found.

  16. Supernova Feedback and the Hot Gas Filling Fraction of the Interstellar Medium

    CERN Document Server

    Li, Miao; Cen, Renyue; Bryan, Greg L; Naab, Thorsten

    2015-01-01

    Supernovae are the most energetic among stellar feedback processes, and are crucial for regulating the interstellar medium (ISM) and launching galactic winds. We explore how supernova remnants (SNRs) create a multiphase medium by performing high resolution, 3D hydrodynamical simulations at various SN rates, $S$, and ISM average densities, $n$. We find that the evolution of a SNR in a self-consistently generated three-phase ISM is qualitatively different from that in a uniform or a two-phase warm/cold medium. By traveling faster and further in the cooling-inefficient hot phase, the spatial-temporal domain of a SNR is enlarged by $>10^{2.5}$ in a hot-dominated multiphase medium (HDMM) compared to the uniform case. We then examine the resultant ISM as we vary $n$ and $S$, finding that a steady state can only be achieved when the hot gas volume fraction \\fvh $\\lesssim 0.6\\pm 0.1$. Above that, overlapping SNRs render connecting topology of the hot gas, and such a HDMM is subjected to thermal runaway with growing p...

  17. Effects of Ar or O2 Gas Bubbling for Shape, Size, and Composition Changes in Silver-Gold Alloy Nanoparticles Prepared from Galvanic Replacement Reaction

    Directory of Open Access Journals (Sweden)

    Md. Jahangir Alam

    2013-01-01

    Full Text Available The galvanic replacement reaction between silver nanostructures and AuCl4- solution has recently been demonstrated as a versatile method for generating metal nanostructures with hollow interiors. Here we describe the results of a systematic study detailing the morphological, structural, compositional, and spectral changes involved in such a heterogeneous reaction on the nanoscale. Effects of Ar or O2 gas bubbling for the formation of Ag-Au alloy nanoparticles by the galvanic replacement between spherical Ag nanoparticles and AuCl4- especially were studied in ethylene glycol (EG at 150°C. The shape, size, and composition changes occur rapidly under O2 bubbling in comparison with those under Ar bubbling. The major product after 60 min heating under Ar gas bubbling was perforated Ag-Au alloy particles formed by the replacement reaction and the minor product was ribbon-type particles produced from splitting off some perforated particles. On the other hand, the major product after 60 min heating under O2 gas bubbling was ribbon-type particles. In addition, small spherical Ag particles are produced. They are formed through rereduction of Ag+ ions released from the replacement reaction and oxidative etching of Ag nanoparticles by O2/Cl− in EG.

  18. Effect of O2/Ar Gas Flow Ratios on Properties of Cathodic Vacuum Arc Deposited ZnO Thin Films on Polyethylene Terephthalate Substrate

    Directory of Open Access Journals (Sweden)

    Chien-Wei Huang

    2016-01-01

    Full Text Available Cathodic vacuum arc deposition (CVAD can obtain a good quality thin film with a low growth temperature and a high deposition rate, thus matching the requirement of film deposition on flexible electronics. This paper reported the room-temperature deposition of zinc oxide (ZnO thin films deposited by CVAD on polyethylene terephthalate (PET substrate. Microstructure, optical, and electrical measurements of the deposited ZnO thin films were investigated with various O2/Ar gas flow ratios from 6 : 1 to 10 : 1. The films showed hexagonal wurtzite crystal structure. With increasing the O2/Ar gas flow ratios, the c-axis (002 oriented intensity decreased. The crystal sizes were around 16.03 nm to 23.42 nm. The average transmittance values in the visible range of all deposited ZnO films were higher than 83% and the calculated band gaps from the absorption data were found to be around 3.1 to 3.2 eV. The resistivity had a minimum value in the 3.65 × 10−3 Ω·cm under the O2/Ar gas flow ratio of 8 : 1. The luminescence mechanisms of the deposited film were also investigated to understand the defect types of room-temperature grown ZnO films.

  19. Integrated processing of contrast pulse sequencing ultrasound imaging for enhanced active contrast of hollow gas filled silica nanoshells and microshells.

    Science.gov (United States)

    Ta, Casey N; Liberman, Alexander; Paul Martinez, H; Barback, Christopher V; Mattrey, Robert F; Blair, Sarah L; Trogler, William C; Kummel, Andrew C; Wu, Zhe

    2012-03-01

    In recent years, there have been increasing developments in the field of contrast-enhanced ultrasound both in the creation of new contrast agents and in imaging modalities. These contrast agents have been employed to study tumor vasculature in order to improve cancer detection and diagnosis. An in vivo study is presented of ultrasound imaging of gas filled hollow silica microshells and nanoshells which have been delivered intraperitoneally to an IGROV-1 tumor bearing mouse. In contrast to microbubbles, this formulation of microshells provided strong ultrasound imaging signals by shell disruption and release of gas. Imaging of the microshells in an animal model was facilitated by novel image processing. Although the particle signal could be identified by eye under live imaging, high background obfuscated the particle signal in still images and near the borders of the tumor with live images. Image processing techniques were developed that employed the transient nature of the particle signal to selectively filter out the background signal. By applying image registration, high-pass, median, threshold, and motion filtering, a short video clip of the particle signal was compressed into a single image, thereby resolving the silica shells within the tumor. © 2012 American Vacuum Society.

  20. Synchrotron X-Ray Study of Melting in Submonolayer Ar and other Rare-Gas Films on Graphite

    DEFF Research Database (Denmark)

    McTague, J. P.; Als-Nielsen, Jens Aage; Bohr, Jakob;

    1982-01-01

    Synchrotron x-ray diffraction studies of the (10) peak of Ar on the (001) surface of ZYX graphite show a sharp but continuous broadening of the Bragg peak with increasing temperature. Below a coverage of ∼ 1 Ar atom per six surface carbon atoms (ρ=1) the onset of this transition occurs at a cover...... at a coverage-independent temperature T=47.9 K. We interpret this point as a critical end point for melting. For coverages 0.94...

  1. The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications

    CERN Document Server

    Ciocarlan, C.; Islam, M. R.; Ersfeld, B.; Abuazoum, S.; Wilson, R.; Aniculaesei, C.; Welsh, G. H.; Vieux, G.; Jaroszynski, D. A.; 10.1063/1.4822333

    2013-01-01

    The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive selffocusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as a laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.01018 cm3, the peak normalized...

  2. High harmonic generation in a gas-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Heckl, O. H.; Baer, C. R. E.; Kränkel, C.; Marchese, S. V.; Schapper, F.; Holler, M.; Südmeyer, T.; Robinson, J. S.; Tisch, J. W. G.; Couny, F.; Light, P.; Benabid, F.; Keller, U.

    2009-10-01

    High harmonic generation (HHG) of intense infrared laser radiation (Ferray et al., J. Phys. B: At. Mol. Opt. Phys. 21:L31, 1988; McPherson et al., J. Opt. Soc. Am. B 4:595, 1987) enables coherent vacuum-UV (VUV) to soft-X-ray sources. In the usual setup, energetic femtosecond laser pulses are strongly focused into a gas jet, restricting the interaction length to the Rayleigh range of the focus. The average photon flux is limited by the low conversion efficiency and the low average power of the complex laser amplifier systems (Keller, Nature 424:831, 2003; Südmeyer et al., Nat. Photonics 2:599, 2008; Röser et al., Opt. Lett. 30:2754, 2005; Eidam et al., IEEE J. Sel. Top. Quantum Electron. 15:187, 2009) which typically operate at kilohertz repetition rates. This represents a severe limitation for many experiments using the harmonic radiation in fields such as metrology or high-resolution imaging. Driving HHG with novel high-power diode-pumped multi-megahertz laser systems has the potential to significantly increase the average photon flux. However, the higher average power comes at the expense of lower pulse energies because the repetition rate is increased by more than a thousand times, and efficient HHG is not possible in the usual geometry. So far, two promising techniques for HHG at lower pulse energies were developed: external build-up cavities (Gohle et al., Nature 436:234, 2005; Jones et al., Phys. Rev. Lett. 94:193, 2005) and resonant field enhancement in nanostructured targets (Kim et al., Nature 453:757, 2008). Here we present a third technique, which has advantages in terms of ease of HHG light extraction, transverse beam quality, and the possibility to substantially increase conversion efficiency by phase-matching (Paul et al., Nature 421:51, 2003; Ren et al., Opt. Express 16:17052, 2008; Serebryannikov et al., Phys. Rev. E (Stat. Nonlinear Soft Matter Phys.) 70:66611, 2004; Serebryannikov et al., Opt. Lett. 33:977, 2008; Zhang et al., Nat. Phys. 3

  3. Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices.

    Science.gov (United States)

    Pejović, Milić M; Denić, Dragan B; Pejović, Momčilo M; Nešić, Nikola T; Vasović, Nikola

    2010-10-01

    This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

  4. Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices

    Energy Technology Data Exchange (ETDEWEB)

    Pejovic, Milic M.; Denic, Dragan B.; Pejovic, Momcilo M.; Nesic, Nikola T.; Vasovic, Nikola [Faculty of Electronic Engineering, University of Nis, Aleksandra Medvedeva 14, 18000 Nis (Serbia)

    2010-10-15

    This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

  5. Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices

    Science.gov (United States)

    Pejović, Milić M.; Denić, Dragan B.; Pejović, Momčilo M.; Nešić, Nikola T.; Vasović, Nikola

    2010-10-01

    This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

  6. Fijación de arsénico en fase gas con hematita sólida

    Directory of Open Access Journals (Sweden)

    Balladares, E.

    2004-10-01

    Full Text Available Feasibility to obtain ferric arsenate starting from arsenic containing gas in contact with Fe2 O3 has been studied. Thermodynamic stability of the system Fe-As-O was analysed in order to verify conditions to form FexAsy y Oz type compounds. Experiments were made using a hematite sample suspended in a thermogravimetric device. As4O6 was generated starting from solid As2 O3 which was circulating through the iron oxide. Final samples were analysed chemically and by means of DRX, verifying the formation of FeAsO4, FeAsO4·2H2O and FeAsO4·(H2O2 in small quantities. Tests in porous bed and pellets were carried out, studying the effect of: porosity, temperature and oxygen potential. The largest conversion obtained was 10 % at 800 °C, pO2 =50% and porosity = 0.883.

    Se estudió, a escala laboratorio, la factibilidad de obtener arseniato férrico a partir de una corriente gaseosa rica en arsénico, en contacto con Fe2 O3. Se analizó la estabilidad termodinámica del sistema Fe-As-O a fin de verificar las condiciones de formación de compuestos del tipo FexAsy y Oz. Se usó una muestra de hematita suspendida de una balanza termogravimétrica. El gas As4O6 fue generado a partir de AS2 O3 sólido y se hizo circular a través del óxido de hierro. Las muestras obtenidas fueron analizadas químicamente y mediante DRX, verificándose la formación de cantidades menores de FeAsO4, FeAsO4·2H2O y FeAsO4·(H2O2. Se estudió el efecto de porosidad, temperatura y presión parcial de oxígeno. La mayor conversión obtenida fue de 10 %, a 800 °C, pO2 = 50 % y porosidad = 0,883.

  7. MOLECULAR DYNAMICS SIMULATIONS OF FILLED AND EMPTY CAGE-LIKE WATER CLUSTERS IN LIQUID WATER AND THEIR SIGNIFICANCE TO GAS HYDRATE FORMATION MECHANISMS

    Institute of Scientific and Technical Information of China (English)

    GUO Guangjun; ZHANG Yigang; ZHAO Yajuan

    2003-01-01

    Molecular dynamics simulations are performed to observe the evolutions of 512 and 51262 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 230 K. The lifetimes of these clusters are calculated according to their Lindemann index δ (t) using the criteria of δ≥0.07. For both the filled and empty clusters, we find the dynamics of bulk water determines the lifetimes of cage-like water clusters, and that the lifetime of 512 62 cage-like cluster is the same as that of 512 cage-like cluster. Although the methane molecule indeed makes the filled cage-like cluster more stable than the empty one, the empty cage-like cluster still has chance to be long-lived compared with the filled clusters. These observations support the labile cluster hypothesis on the formation mechanisms of gas hydrates.

  8. Computational modelling of the interaction of shock waves with multiple gas-filled bubbles in a liquid

    Science.gov (United States)

    Betney, M. R.; Tully, B.; Hawker, N. A.; Ventikos, Y.

    2015-03-01

    This study presents a computational investigation of the interactions of a single shock wave with multiple gas-filled bubbles in a liquid medium. This work illustrates how multiple bubbles may be used in shock-bubble interactions to intensify the process on a local level. A high resolution front-tracking approach is used, which enables explicit tracking of the gas-liquid interface. The collapse of two identical bubbles, one placed behind the other is investigated in detail, demonstrating that peak pressures in a two bubble arrangement can exceed those seen in single bubble collapse. Additionally, a parametric investigation into the effect of bubble separation is presented. It is found that the separation distance has a significant effect on both the shape and velocity of the main transverse jet of the second bubble. Extending this analysis to effects of relative bubble size, we show that if the first bubble is sufficiently small relative to the second, it may become entirely entrained in the second bubble main transverse jet. In contrast, if the first bubble is substantially larger than the second, it may offer it significant protection from the incident shock. This protection is utilised in the study of a triangular array of three bubbles, with the central bubble being significantly smaller than the outer bubbles. It is demonstrated that, through shielding of bubbles until later in the collapse process, pressures over five times higher than the maximum pressure observed in the single bubble case may be achieved. This corresponds to a peak pressure that is approximately 40 times more intense than the incident shock wave. This work has applications in a number of different fields, including cavitation erosion, explosives, targeted drug delivery/intensification, and shock wave lithotripsy.

  9. Coherent Population Trapping Resonances in Buffer Gas-filled Cs Vapor Cells with Push-Pull Optical Pumping

    CERN Document Server

    Liu, Xiaochi; Guérandel, Stéphane; Gorecki, Christophe; de Clercq, Emeric; Boudot, Rodolphe

    2013-01-01

    We report on a theoretical study and experimental characterization of coherent population trapping (CPT) resonances in buffer gas-filled vapor cells with push-pull optical pumping (PPOP) on Cs D1 line. We point out that the push-pull interaction scheme is identical to the so-called lin per lin polarization scheme. Expressions of the relevant dark states, as well as of absorption, are reported. The experimental setup is based on the combination of a distributed feedback (DFB) diode laser, a pigtailed intensity Mach-Zehnder electro-optic modulator (MZ EOM) for optical sidebands generation and a Michelson-like interferometer. A microwave technique to stabilize the transfer function operating point of the MZ EOM is implemented for proper operation. A CPT resonance contrast as high as 78% is reported in a cm-scale cell for the magnetic-field insensitive clock transition. The impact of the laser intensity on the CPT clock signal key parameters (linewidth - contrast - linewidth/contrast ratio) is reported for three ...

  10. FIBER LASER CONSTRUCTION AND THEORY INCLUDING FIBER BRAGG GRATINGS Photonic Crystal Fibers (PCFs) and applications of gas filled PCFs

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Jacob O. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-08

    The principles used in fiber lasers have been around for a while but it is only within the past few years that fiber lasers have become commercially available and used in high power laser applications. This paper will focus on the basic design principles of fiber lasers, including fiber Bragg gratings, principles of operation, and forms of non-linear effects. It will describe the type and associated doping of the fiber used and difficult designs used to guide energy from the pump to the active medium. Topics covered include fiber laser design, fiber Bragg gratings, materials used, differences in quantum energy loss, thermo-optical effects, stimulated Raman scattering, Brillouin scattering, photonic crystal fibers and applications of gas filled Photonic Crystal Fibers (PCFs). Thanks to fiber lasers, the energy required to produce high power lasers has greatly dropped and as such we can now produce kW power using a standard 120V 15A circuit. High power laser applications are always requiring more power. The fiber laser can now deliver the greater power that these applications demand. Future applications requiring more power than can be combined using standard materials or configurations will need to be developed to overcome the high energy density and high non-linear optical scattering effects present during high power operations.

  11. Understanding the dynamics of photoionization-induced solitons in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F

    2011-01-01

    We present in detail our developed model [Saleh et al., Phys. Rev. Lett. 107] that governs pulse propagation in hollow-core photonic crystal fibers filled by an ionizing gas. By using perturbative methods, we find that the photoionization process induces the opposite phenomenon of the well-known Raman self-frequency red-shift of solitons in solid-core glass fibers, as was recently experimentally demonstrated [Hoelzer et al., Phys. Rev. Lett. 107]. This process is only limited by ionization losses, and leads to a constant acceleration of solitons in the time domain with a continuous blue-shift in the frequency domain. By applying the Gagnon-B\\'{e}langer gauge transformation, multi-peak `inverted gravity-like' solitary waves are predicted. We also demonstrate that the pulse dynamics shows the ejection of solitons during propagation in such fibers, analogous to what happens in conventional solid-core fibers. Moreover, unconventional long-range non-local interactions between temporally distant solitons, unique of...

  12. Understanding fast neutrons utilizing a water Cherenkov detector and a gas-filled detector at the soudan underground laboratory

    Science.gov (United States)

    Ghimire, Chiranjibi

    Many experiments are currently searching for Weakly Interactive Massive Particles (WIMPs), a well-motivated class of hypothetical dark matter candidates. These direct dark matter detection experiments are located in deep underground to shield from cosmic-ray muons and the fast neutrons they produce. Fast neutrons are particularly dangerous to WIMP detectors because they can penetrate a WIMP-search experiment's neutron shielding. Once inside, these fast neutrons can interact with high-Z material near the WIMP detector, producing slower neutrons capable of mimicking the expected WIMP signal. My research uses two detectors located in Soudan Underground Laboratory to understand fast neutron production by muons in an underground environment: a water-Cherenkov detector sensitive to fast neutrons; and a gas-filled detector sensitive to charged particles like muons. The different kinds of selection criterion and their efficiencies are reported in this thesis. This thesis estimate the number of high energy neutron-like candidates associated with a nearby muon by using data from both detector systems.

  13. Measurement of the viscosities of He, Ne and Ar for the determination of their gas – kinetic diameters.

    Directory of Open Access Journals (Sweden)

    P.N. Ekemezie

    2015-11-01

    Full Text Available The viscosities of He, Ne and Ar gases were measured using pressure transducer to obtain the pressure, time data. Using the viscosity of dry air at the measured 320C ambient temperature, the evacuation data (pressure, time were converted to viscosity values thus: He (1.03 x 10-4 poise, Ne (1.72 x 10-4 poise, and Ar (1.96 x 10-4 poise. Finally, the collision diameter of the gases were calculated using appropriate equations to obtain He (0.19nm, Ne (0.22nm, and Ar (0.33nm. The values obtained were compared with those of literature (He = 0.21nm, Ne = 0.24nm, Ar = 0.36nm. Since the values of collision diameter obtained in this experiment are in conformity with those obtained from literature, we can safely conclude that measurement of collision diameter can be used as a quality assay for gases.

  14. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  15. A velocity map imaging study of gold-rare gas complexes: Au-Ar, Au-Kr, and Au-Xe

    Science.gov (United States)

    Hopkins, W. Scott; Woodham, Alex P.; Plowright, Richard J.; Wright, Timothy G.; Mackenzie, Stuart R.

    2010-06-01

    The ultraviolet photodissociation dynamics of the gold-rare gas atom van der Waals complexes (Au-RG, RG=Ar, Kr, and Xe) have been studied by velocity map imaging. Photofragmentation of Au-Ar and Au-Kr at several wavelengths permits extrapolation to zero of the total kinetic energy release (TKER) spectra as monitored in the Au(P23/2∘[5d106p]) fragment channel, facilitating the determination of ground state dissociation energies of D0″(Au-Ar)=149±13 cm-1 and D0″(Au-Kr)=240±19 cm-1, respectively. In the same spectral region, transitions to vibrational levels of an Ω'=1/2 state of the Au-Xe complex result in predissociation to the lower Au(P21/2∘[5d106p])+Xe(S10[5p6]) fragment channel for which TKER extrapolation yields a value of D0″(Au-Xe)=636±27 cm-1. Asymmetric line shapes for transitions to the v'=14 level of this state indicate coupling to the Au(P23/2∘[5d106p])+Xe(S10[5p6]) continuum, which allows us to refine this value to D0″(Au-Xe)=607±5 cm-1. The dissociation dynamics of this vibrational level have been studied at the level of individual isotopologues by fitting the observed excitation spectra to Fano profiles. These fits reveal a remarkable variation in the predissociation dynamics for different Au-Xe isotopologues. For Au-Ar and Au-Xe, the determined ground state dissociation energies are in good agreement with recent theoretical calculations; the agreement of the Au-Kr value with theory is less satisfactory.

  16. Multistage plasma initiation process by pulsed CO2 laser irradiation of a Ti sample in an ambient gas (He, Ar, or N2)

    Science.gov (United States)

    Hermann, J.; Boulmer-Leborgne, C.; Mihailescu, I. N.; Dubreuil, B.

    1993-02-01

    New experimental results are reported on plasma initiation in front of a titanium sample irradiated by ir (λ=10.6 μm) laser pulses in an ambient gas (He, Ar, and N2) at pressures ranging from several Torr up to the atmosphere. The plasma is studied by space- and time-resolved emission spectroscopy, while sample vaporization is probed by laser-induced fluorescence spectroscopy. Threshold laser intensities leading to the formation of a plasma in the vapor and in the ambient gases are determined. Experimental results support the model of a vaporization mechanism for the plasma initiation (vaporization-initiated plasma breakdown). The plasma initiation is described by simple numerical criteria based on a two-stage process. Theoretical predictions are found to be in a reasonable agreement with the experiment. This study provides also a clear explanation of the influence of the ambient gas on the laser beam-metal surface energy transfer. Laser irradiation always causes an important vaporization when performed in He, while in the case of Ar or N2, the interaction is reduced in heating and vaporization of some surface defects and impurities.

  17. Ionization-induced asymmetric self-phase modulation and universal modulational instability in gas-filled hollow-core photonic crystal fibers

    CERN Document Server

    Saleh, Mohammed F; Travers, John C; Russell, Philip St J; Biancalana, Fabio

    2012-01-01

    We study theoretically the propagation of relatively long pulses with ionizing intensities in a hollow-core photonic crystal fiber filled with a Raman-inactive gas. Due to photoionization, previously unknown types of asymmetric self-phase modulation and `universal' modulational instabilities existing in both normal and anomalous dispersion regions appear. We also show that it is possible to spontaneously generate a plasma-induced continuum of blueshifting solitons, opening up new possibilities for pushing supercontinuum generation towards shorter and shorter wavelengths.

  18. Theoretical Description of the Third Order Parametric Wave Mixing in a Gas-Filled Capillary of Femto-Second Laser Pulse

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2004-01-01

    The theoretical signal-pressure curves are calculated from approximate analytical solutions of the coupledequations describing the third order parametric wave mixing in a gas-filled capillary of femto-second laser pulses. Thecomparison with the corresponding experimental curves suggests that the following three factors exert important influ-ences on the degree of fitting between the theoretical and experimental results: the walk-off, the phase modulation, andthe third order harmonic of idler pulse.

  19. DoD’s Compressed Natural Gas Filling Station in Afghanistan: An Ill-conceived $43 Million Project

    Science.gov (United States)

    2015-10-01

    reserves of natural gas, along with deposits of oil and natural gas liquids .3 The TFBSO Downstream Gas Utilization Project was intended to take...market for CNG vehicles. According to the World Bank , “[t]he cost of distribution of natural gas to a large number of small consumers can be...appendix I). 12 John Homer, The World Bank , Natural Gas in Developing Countries, Evaluating the Benefits to the Environment, January 1993, p. 19

  20. The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. B., E-mail: schneider5@llnl.gov; MacLaren, S. A.; Widmann, K.; Meezan, N. B.; Hammer, J. H.; Yoxall, B. E.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Dewald, E. L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Hinkel, D. E.; Hsing, W. W.; Kervin, M. L.; Landen, O. L.; Lindl, J. D.; May, M. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

    2015-12-15

    At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer.

  1. Practical experience with the gas lift method during the gas first fill in the Etzel cavern field and further possible applications; Praktische Erfahrungen mit dem Gasliftverfahren bei der Gaserstbefuellung im Kavernenfeld Etzel und weitere Einsatzmoeglichkeiten

    Energy Technology Data Exchange (ETDEWEB)

    Bernhardt, H.; Boor, S. [KBB UT, Hannover (Germany); Reekers, C. [IVG Caverns GmbH, Bonn (Germany)

    2011-11-15

    The further development of the Etzel cavern field by IVG Caverns GmbH involves converting crude oil caverns to natural gas storage caverns. The planning and technical supervision of the conversion project is managed by KBB Underground Technologies GmbH. The large heights of the oil caverns meant that the brine-filled caverns could not be completely filled with natural gas in the conventional way i. e. injecting natural gas to displace the brine. This is because the maximum permissible gas injection pressure has to be exceeded when the gas / brine interface drops beyond a certain depth. The maximum permissible gas pressure is primarily determined by the depth of the last cemented casing shoe and limits the gas pressure that can be safely used during brine displacement. In the case presented here, the limit meant that the brine could not be removed from the lower part of the cavern using conventional means, which would have left valuable cavern volume unutilised. (orig.)

  2. New Empirical Potential Energy Functions for the Heavier Homonuclear Rare Gas Pairs: {Ne}_2, {Ar}_2, {Kr}_2, and {Xe}_2

    Science.gov (United States)

    Myatt, Philip Thomas; Baker, Matthew T.; Kang, Ju-Hee; Escobar Moya, Andres; McCourt, Frederick R. W.; Le Roy, Robert J.

    2016-06-01

    The many decades of work on determining accurate analytic pair potentials for rare gas dimers from experimental data focussed largely on the use of bulk non-ideal gas and collisional properties, with the use of spectroscopic data being somewhat of an afterthought, for testing the resulting functions. This was a natural result of experimental challenges, as the very weak binding of ground-state rare gas pairs made high resolution spectroscopy a relatively late arrival as a practical tool in this area. However, we believe that it is now time for a comprehensive reassessment. Following up on a preliminary report at this meeting five years ago, this paper describes work to determine a new generation of empirical potential energy functions for the four heavier (i.e., not involving He) homonuclear rare gas pairs from direct fits to all available spectroscopic, pressure virial, and acoustic virial coefficient data, with the resulting functions being `tuned' by comparisons with available thermal transport property data: viscosity, mass diffusion and thermal diffusion, and thermal conductivity data, and tested against the best available ab initio potentials. The resulting functions are everywhere smooth and differentiable to all orders, incorporate the correct (damped) theoretical inverse-power long-range behaviour, and have sensible short-range extrapolation behaviour. R.J. Le Roy, C.J.W. Mackie, P. Chandrasekhar and K.M. Sentjens, ``Accurate New Potential Energy Functions From Spectroscopic and Virial Coefficient Data for the Ten Rare Gas Pairs formed from Ne, Ar, Kr and Xe, paper MF03 at the 66th Ohio State University International Symposium on Molecular Spectroscopy, Columbus, Ohio, June 13-17 (2011).

  3. Ars Electronica

    DEFF Research Database (Denmark)

    Kristensen, Thomas Bjørnsten

    2009-01-01

    Anmeldelse af Ars Electronica festivalen 3. - 8. september, 2009 i Linz, Østrig, der fejrede 30 års jubilæum under temaet "Human Nature". Festivalen fokuserer på interaktion mellem menneske, teknologi, kunst og samfund med særlig vægt på udviklingen af computeren og det digitale. Udgivelsesdato: 15.12...

  4. Spectrum Blueshifting of Ultrashort UV Laser Pulse Induced by Ionization of Supersonic He and Ar Gas Jets

    Institute of Scientific and Technical Information of China (English)

    YAN Lixin; ZHANG Yongsheng; LIU Jingru; HUANG Wenhui; TANG Chuanxiang; CHENG Jianping

    2008-01-01

    The predominant spectral blueshifting of a sub-picosecond UV laser pulse induced by ultrafast ionization of noble gases was investigated. Spectral measurements were made at various gas densities. Typical quasi-periodic structures in the blueshifted spectrum were obtained. The observations were in connection with the so-called self-phase modulation of laser pulses in the ultrafast ionization process which was simply simulated with an ADK (Ammosov-Delone-Krainov) ionization model. Some quantitative information can be deduced from the measurements and calculations.

  5. Raman-free, noble-gas-filled PCF source for ultrafast, very bright twin-beam squeezed vacuum

    CERN Document Server

    Finger, Martin A; Joly, Nicolas Y; Chekhova, Maria V; Russell, Philip St J

    2015-01-01

    We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagom\\'e-style photonic-crystal fibre. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ~2500 photons per mode. The ultra-broadband (~50 THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes.

  6. Dramatic Raman Gain Suppression in the Vicinity of the Zero Dispersion Point in Gas-Filled Hollow-Core Photonic Crystal Fiber

    CERN Document Server

    Bauerschmidt, Sebastian T; Russell, Philip St J

    2015-01-01

    In 1964 Bloembergen and Shen predicted that Raman gain could be suppressed if the rates of phonon creation and annihilation (by inelastic scattering) exactly balance. This is only possible if the momentum required for each process is identical, i.e., phonon coherence waves created by pump-to-Stokes scattering are identical to those annihilated in pump-to-anti-Stokes scattering. In bulk gas cells, this can only be achieved over limited interaction lengths at an oblique angle to the pump axis. Here we report a simple system that provides dramatic Raman gain suppression over long collinear path-lengths in hydrogen. It consists of a gas-filled hollow-core photonic crystal fiber whose zero dispersion point is pressure-adjusted to lie close to the pump laser wavelength. At a certain precise pressure, generation of Stokes light in the fundamental mode is completely suppressed, allowing other much weaker nonlinear processes to be explored.

  7. Photoionization-induced emission of tunable few-cycle mid-IR dispersive waves in gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Novoa, David; Travers, John C; Russell, Philip St J

    2015-01-01

    We propose a scheme for the emission of few-cycle dispersive waves in the mid-infrared using hollow-core photonic crystal fibers filled with noble gas. The underlying mechanism is the formation of a plasma cloud by a self-compressed, sub-cycle pump pulse. The resulting free-electron population modifies the fiber dispersion, allowing phase-matched access to dispersive waves at otherwise inaccessible frequencies, well into the mid-IR. Remarkably, the pulses generated turn out to have durations of the order of two optical cycles. In addition, this ultrafast emission, which occurs even in the absence of a zero dispersion point between pump and mid-IR wavelengths, is tunable over a wide frequency range simply by adjusting the gas pressure. These theoretical results pave the way to a new generation of compact, fiber-based sources of few-cycle mid-IR radiation.

  8. The self–vibrations of cylindrical shell, filled by the flowing non viscous Gas-Liquid mixture

    Directory of Open Access Journals (Sweden)

    Ohanyan G.G.

    2014-03-01

    Full Text Available The problem of non-symmetrical self–vibrations of the infinite long shell, filled by the flowing non viscous Liquid with large or small sizes of bubbles is considered. The subsonic regime of the shell–mixture system with small bubbles which vibration frequencies exceed the frequencies values of those with the large bubbles is considered. The frequency values of the system is increased, when shell thickness and flow speed are increased as when vibration modes are decreased analogous to the case of shell with the pure liquids.

  9. Enfoque “Aprendizaje Basado en Proyectos” para enseñar sistemas de potencia de gas y vapor

    Directory of Open Access Journals (Sweden)

    Asier Aranzábal

    2014-12-01

    Full Text Available El objetivo de este trabajo es presentar la experiencia y los resultados derivados de la aplicación del método Aprendizaje Basado en Proyectos (PBL en la asignatura Termotecnia de la Titulación de Ingeniería Química de la Universidad del País Vasco/Euskal Herriko Unibertsitatea, para aprender sistemas de potencia de gas y vapor. Tras un análisis crítico de los resultados académicos de los alumnos que aprenden estos sistemas, se observa que la estrategia de enseñanza-aprendizaje tradicional, basada en clases “magistrales + clases de aplicación en una lista de ejercicios (totalmente acotados y con una solución única, estaba fallando. Ante esta situación se plantea un enfoque constructivista centrado en el alumno para que él mismo construya su aprendizaje activa y cooperativamente, y no escuchando clases magistrales, ni memorizando.

  10. Increasing of the gas turbine efficiency by inlet air cooling; Aumento da eficiencia de turbinas a gas por resfriamento do ar de admissao

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Flavio Barboza [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas]. E-mail: fcampos@cenpes.petrobras.com.br; Landa, Henrique Gerken de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Pesquisa, Desenvolvimento e Engenharia de Gas e Energia]. E-mail: hlanda@cenpes.petrobras.com.br

    2002-07-01

    The performance of most of gas turbines are affected by the temperature and pressure environmental conditions. The turbine power and efficiency are reduced by either the increasing in the temperature ou reducing the environmental pressure. This paper analyses the turbine inlet air cooling as an alternative for increasing the turbine efficiency. The various cooling routes of the turbine inlet air, found in the literature examined are presented and discussed.

  11. Purification and Detection of 39Ar in Groundwater Samples via Low-Level Counting

    Science.gov (United States)

    Mace, E. K.; Aalseth, C.; Brandenberger, J. M.; Humble, P.; Panisko, M.; Seifert, A.; Williams, R. M.

    2015-12-01

    Argon-39 can be used as a radiotracer to age-date groundwater aquifers to study recharge rates and to better understand the mean residence time, or age distributions, of groundwater. Argon-39 (with a half-life of 269 years) is created in the atmosphere by cosmic rays interacting with argon in the air (primarily 40Ar). The use of 39Ar as a radiotracer fills a gap in the age dating range which is currently covered by 3H/3He or 85Kr (1000 years); 39Ar fills the intermediate time scale range from 50-1000 years where the previously established radiotracers are not adequate. We will introduce the process for purifying and detecting 39Ar in ground water using ultra-low-background proportional counters (ULBPCs) at the shallow underground laboratory at Pacific Northwest National Laboratory. Argon-39 is detected through direct beta counting using ULBPCs loaded with a mixture of geologic argon (extracted from a carbon dioxide well with no measureable 39Ar activity) and methane, which enhances the sensitivity for 39Ar measurements. The ULBPCs have been shown to have a background count rate of 148 counts per day (cpd) in the energy range 3-400 keV when filled with 10 atm of P-10 counting gas (90% geologic Ar, 10% CH4). Initial demonstration samples were collected from groundwater aquifers in Fresno, California supported by the United States Geological Survey (USGS). A discussion of the sampling technique to degas the water from these wells and to then purify it for counting will be presented. In order to quantify the 39Ar contribution in the groundwater samples, the ULBPCs were characterized to determine two components: 1) the detector efficiency to modern levels of 39Ar, and 2) the remaining detector background (using geologic sourced argon which is free from 39Ar - no measureable 39Ar activity). These characterization results will be presented along with a discussion of the quantification of the 39Ar age of the demonstration measurements.

  12. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  13. Mechanism and computational model for Lyman-α-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Science.gov (United States)

    Louchev, Oleg A.; Bakule, Pavel; Saito, Norihito; Wada, Satoshi; Yokoyama, Koji; Ishida, Katsuhiko; Iwasaki, Masahiko

    2011-09-01

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-α (Ly-α) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-α generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-α radiation generation can achieve a value of ˜5×10-4 which is restricted by the total combined absorption of the fundamental and generated radiation.

  14. Performance of a gas flow ionization detector filled with He-iso-C4H10 mixtures for STIM-T

    Science.gov (United States)

    Marques, A. C.; Fraga, M. M. F. R.; Fonte, P.; Beasley, D. G.; Cruz, C.; Alves, L. C.; da Silva, R. C.

    2015-04-01

    A cylindrical gas flow ionization chamber has been developed for measuring particle energy in Scanning Transmission Ion Microscopy Tomography (STIM-T) experiments due to its ability to withstand the direct beam. The response of a He-iso-C4H10 filled ionization detector to 2 MeV H+ and He+ beams was studied. Different operating parameters, such as concentration of isobutane (in the range of 55-100%), anode voltage, amplifier shaping time, the geometry of the detector entrance canal and the solid angle of the detector, were investigated. The stable operating plateau and the anode voltage at which the best energy resolution is attained were also determined for every gas mixture. The best energy resolution achieved so far for 2 MeV H+ and He+ static beams was ∼1.3%, which is comparable to that of Si PIN diode detectors (in the range of 15-30 keV). Computed tomography (CT) was applied to a set of STIM projections acquired with the gas ionization chamber at the IST/CTN microprobe beam line in order to visualize the 3D-mass distribution in a test structure.

  15. Performance of a gas flow ionization detector filled with He-iso-C{sub 4}H{sub 10} mixtures for STIM-T

    Energy Technology Data Exchange (ETDEWEB)

    Marques, A.C. [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Fraga, M.M.F.R. [Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra (Portugal); Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Fonte, P. [Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra (Portugal); Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra (Portugal); Beasley, D.G. [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Cruz, C. [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Alves, L.C. [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Silva, R.C. da [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2695-066 Bobadela LRS (Portugal); Centro de Física Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal)

    2015-04-01

    A cylindrical gas flow ionization chamber has been developed for measuring particle energy in Scanning Transmission Ion Microscopy Tomography (STIM-T) experiments due to its ability to withstand the direct beam. The response of a He-iso-C{sub 4}H{sub 10} filled ionization detector to 2 MeV H{sup +} and He{sup +} beams was studied. Different operating parameters, such as concentration of isobutane (in the range of 55–100%), anode voltage, amplifier shaping time, the geometry of the detector entrance canal and the solid angle of the detector, were investigated. The stable operating plateau and the anode voltage at which the best energy resolution is attained were also determined for every gas mixture. The best energy resolution achieved so far for 2 MeV H{sup +} and He{sup +} static beams was ∼1.3%, which is comparable to that of Si PIN diode detectors (in the range of 15–30 keV). Computed tomography (CT) was applied to a set of STIM projections acquired with the gas ionization chamber at the IST/CTN microprobe beam line in order to visualize the 3D-mass distribution in a test structure.

  16. Shaping frequency correlations of ultrafast pulse-pumped modulational instability in gas-filled hollow-core PCF

    CERN Document Server

    Finger, Martin A; Russell, Philip St J; Chekhova, Maria V

    2016-01-01

    We vary the time-frequency mode structure of ultrafast pulse-pumped modulational instability (MI) in an argon-filled hollow-core kagom\\'e-style PCF by adjusting the pressure, pump pulse chirp, fiber length and parametric gain. Compared to solid-core systems, the pressure dependent dispersion landscape brings increased flexibility to the tailoring of frequency correlations. The resulting mode content is characterized by measuring the multimode second-order correlation function g(2) and by directly observing frequency correlations in single-shot MI spectra. We show that, from such measurements, the shapes and weights of time-frequency Schmidt (TFS) modes can be extracted and that the number of modes directly influences the shot-to-shot pulse-energy and spectral-shape fluctuations in MI. Using this approach we are able to change the number of TFS modes from 1.3 (g(2) = 1.75) to 4 (g(2) = 1.25) using only a single fiber.

  17. Simulation of electron beam formation and transport in a gas-filled electron-optical system with a plasma emitter

    Science.gov (United States)

    Grishkov, A. A.; Kornilov, S. Yu.; Rempe, N. G.; Shidlovskiy, S. V.; Shklyaev, V. A.

    2016-07-01

    The results of computer simulations of the electron-optical system of an electron gun with a plasma emitter are presented. The simulations are performed using the KOBRA3-INP, XOOPIC, and ANSYS codes. The results describe the electron beam formation and transport. The electron trajectories are analyzed. The mechanisms of gas influence on the energy inhomogeneity of the beam and its current in the regions of beam primary formation, acceleration, and transport are described. Recommendations for optimizing the electron-optical system with a plasma emitter are presented.

  18. The generation and evolution of anisotropic gas-permeability during viscous deformation in conduit-filling ignimbrites

    Science.gov (United States)

    Kolzenburg, Stephan; Russell, Kelly

    2015-04-01

    Gas-permeability plays a governing role in the pre-explosive pressurization of volcanic edifices. Pressurization may only occur once the total volume flux of gases emitted by an underlying magmatic or hydrothermal source exceeds the flow capacity of the permeable pathways present in the edifice. We have measured the physical properties (strain, porosity, permeability and ultrasonic wave velocities) of breadcrust bombs recovered from the deposits of the 2350 B.P. eruption of Mt Meager, BC, Canada. These rocks represent a conduit-infilling pyroclastic breccia that underwent various degrees of welding and deformation and present a remarkable opportunity to constrain the nature and timescale of mechanical processes operating within explosive volcanic conduits during repose periods between eruptive cycles. Here we present data from permeability measurements along the directions of maximum and minimum shortening which help quantifying the effect of vesicle microstructure on permeability. Permeability is measured by applying a range of confining pressures (between 3.4 and 17.2 MPa) to each sample and imposing a constant head (of 0.2 to 3.5 MPa) across the sample. The permeability is then determined using a modified version of Darcy's law applicable to compressible fluids. These rocks display a profound directionality in the measured physical properties resulting from the deformation-induced fabric. For all samples the permeability across the elongation fabric is highly correlated to the sample porosity whereas along the elongation fabric there is little effect of porosity on permeability. At porosity values of about 20% the permeability seems to reach a minimum at 10-16 m2 and does not change significantly with further reduction of porosity. Further, the effect of confining pressure on the permeability of these samples appears to be more pronounced across the elongation fabric than along the elongation fabric. The deformation fabric has a significant effect on the gas

  19. Three sources and three components of success in detection of ultra-rare alpha decays at the Dubna Gas-Filled Recoil separator

    CERN Document Server

    Tsyganov, Y S

    2015-01-01

    General philosophy of procedure of detecting rare events in the recent experiments with 48Ca projectile at the Dubna Gas-Filled Recoil Separator(DGFRS) aimed to the synthesis of superheavy elements (SHE) has been reviewed. Specific instruments and methods are under consideration. Some historical sources of the successful experiments for Z=112-118 are considered too. Special attention is paid to application of method of active correlations in heavy-ion induced complete fusion nuclear reactions. Example of application in Z=115 experiment is presented. Brief description of the 243Am + 48Ca -> 291-x115+xn experiment is presented too. Some attention is paid to the role of chemical experiments in discoveries of SHEs. The DGFRS detection/monitoring system is presented in full firstly.

  20. Standard practice for examination of Gas-Filled filament-wound composite pressure vessels using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examination of filament-wound composite pressure vessels, for example, the type used for fuel tanks in vehicles which use natural gas fuel. 1.2 This practice requires pressurization to a level equal to or greater than what is encountered in normal use. The tanks' pressurization history must be known in order to use this practice. Pressurization medium may be gas or liquid. 1.3 This practice is limited to vessels designed for less than 690 bar [10,000 psi] maximum allowable working pressure and water volume less than 1 m3 or 1000 L [35.4 ft3]. 1.4 AE measurements are used to detect emission sources. Other nondestructive examination (NDE) methods may be used to gain additional insight into the emission source. Procedures for other NDE methods are beyond the scope of this practice. 1.5 This practice applies to examination of new and in-service filament-wound composite pressure vessels. 1.6 This practice applies to examinations conducted at amb...

  1. Adsorbent filled membranes for gas separation. Part 1. Improvement of the gas separation properties of polymeric membranes by incorporation of microporous adsorbents

    NARCIS (Netherlands)

    Duval, J.-M.; Folkers, B.; Mulder, M.H.V.; Desgrandchamps, G.; Smolders, C.A.

    1993-01-01

    The effect of the introduction of specific adsorbents on the gas separation properties of polymeric membranes has been studied. For this purpose both carbon molecular sieves and zeolites are considered. The results show that zeolites such as silicate-1, 13X and KY improve to a large extent the separ

  2. Pulsed discharge production Ar* metastables

    Science.gov (United States)

    Han, Jiande; Heaven, Michael C.; Emmons, Daniel; Perram, Glen P.; Weeks, David E.; Bailey, William F.

    2016-03-01

    The production of relatively high densities of Ar* metastables (>1012 cm-3) in Ar/He mixtures, at total pressures close to 1 atm, is essential for the efficient operation of an optically pumped Ar* laser. We have used emission spectroscopy and diode laser absorption spectroscopy measurements to observe the production and decay of Ar* in a parallel plate pulsed discharge. With discharge pulses of 1 μs duration we find that metastable production is dominated by processes occurring within the first 100 ns of the gas break-down. Application of multiple, closely spaced discharge pulses yields insights concerning conditions that favor metastable production. This information has been combined with time-resolved measurements of voltage and current. The experimental results and preliminary modeling of the discharge kinetics are presented.

  3. Understanding the dynamics of photoionization-induced nonlinear effects and solitons in gas-filled hollow-core photonic crystal fibers

    Science.gov (United States)

    Saleh, Mohammed F.; Biancalana, Fabio

    2011-12-01

    We present the details of our previously formulated model [Saleh , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.203902 107, 203902 (2011)] that governs pulse propagation in hollow-core photonic crystal fibers filled by an ionizable gas. By using perturbative methods, we find that the photoionization process induces the opposite phenomenon of the well-known Raman self-frequency redshift of solitons in solid-core glass fibers, as was recently experimentally demonstrated [Hölzer , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.203901 107, 203901 (2011)]. This process is only limited by ionization losses, and leads to a constant acceleration of solitons in the time domain with a continuous blueshift in the frequency domain. By applying the Gagnon-Bélanger gauge transformation, multipeak “inverted gravitylike” solitary waves are predicted. We also demonstrate that the pulse dynamics shows the ejection of solitons during propagation in such fibers, analogous to what happens in conventional solid-core fibers. Moreover, unconventional long-range nonlocal interactions between temporally distant solitons, unique of gas plasma systems, are predicted and studied. Finally, the effects of higher-order dispersion coefficients and the shock operator on the pulse dynamics are investigated, showing that the conversion efficiency of resonant radiation into the deep UV can be improved via plasma formation.

  4. Deactivation of CO(v = 1) by n-H/sub 2/ and n-D/sub 2/ in liquid Ar: a comparison with energy transfer in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Lupo, D.W.; Lucas, D.

    1986-10-09

    The rate coefficients for deactivation of vibrationally excited CO by n-H/sub 2/ and n-D/sub 2/ in liquid Ar at 87 K are reported. The results are compared with the measurements for the same processes in the gas phase at low temperature; the rate coefficients are found to be approximately equal in the two phases. These results are compared with the predictions of the isolated binary interaction (IBI) model, which predicts that the energy-transfer rate should be approximately 3 times larger in the liquid phase than in the gas phase for a given concentration of hydrogen or deuterium. Some possible reasons for the discrepancy are discussed.

  5. Ar-Ar_Redux: rigorous error propagation of 40Ar/39Ar data, including covariances

    Science.gov (United States)

    Vermeesch, P.

    2015-12-01

    Rigorous data reduction and error propagation algorithms are needed to realise Earthtime's objective to improve the interlaboratory accuracy of 40Ar/39Ar dating to better than 1% and thereby facilitate the comparison and combination of the K-Ar and U-Pb chronometers. Ar-Ar_Redux is a new data reduction protocol and software program for 40Ar/39Ar geochronology which takes into account two previously underappreciated aspects of the method: 1. 40Ar/39Ar measurements are compositional dataIn its simplest form, the 40Ar/39Ar age equation can be written as: t = log(1+J [40Ar/39Ar-298.5636Ar/39Ar])/λ = log(1 + JR)/λ Where λ is the 40K decay constant and J is the irradiation parameter. The age t does not depend on the absolute abundances of the three argon isotopes but only on their relative ratios. Thus, the 36Ar, 39Ar and 40Ar abundances can be normalised to unity and plotted on a ternary diagram or 'simplex'. Argon isotopic data are therefore subject to the peculiar mathematics of 'compositional data', sensu Aitchison (1986, The Statistical Analysis of Compositional Data, Chapman & Hall). 2. Correlated errors are pervasive throughout the 40Ar/39Ar methodCurrent data reduction protocols for 40Ar/39Ar geochronology propagate the age uncertainty as follows: σ2(t) = [J2 σ2(R) + R2 σ2(J)] / [λ2 (1 + R J)], which implies zero covariance between R and J. In reality, however, significant error correlations are found in every step of the 40Ar/39Ar data acquisition and processing, in both single and multi collector instruments, during blank, interference and decay corrections, age calculation etc. Ar-Ar_Redux revisits every aspect of the 40Ar/39Ar method by casting the raw mass spectrometer data into a contingency table of logratios, which automatically keeps track of all covariances in a compositional context. Application of the method to real data reveals strong correlations (r2 of up to 0.9) between age measurements within a single irradiation batch. Propertly taking

  6. Microstructure Filled Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thomas, C. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reese, T. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-24

    We propose replacing the gas fill in a hohlraum with a low average density, variable uniformity 3D printed structure. This creates a bimodal hohlraum which acts like a vacuum hohlraum initially during the picket, but could protect the capsule from glint or direct illumination, and then once expanded, homogenizes to behave like a variable z gas-fill during peak portion of the drive. This is motivated by a two main aims: 1) reduction of the Au bubble velocity to improve inner beam propagation, and 2) the introduction of a low density, high-Z, x-ray converter to improve x-ray production in the hohlraum and uniformity of the radiation field seen by the capsule.

  7. Stir bar sorptive extraction coupled to gas chromatography-mass spectrometry for the determination of bisphenols in canned beverages and filling liquids of canned vegetables.

    Science.gov (United States)

    Cacho, J I; Campillo, N; Viñas, P; Hernández-Córdoba, M

    2012-07-20

    This paper describes a method for the simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol Z (BPZ) and biphenol (BP), using stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Several parameters affecting both extraction and thermal desorption of the SBSE stages were carefully optimized by multivariate designs. SBSE was performed with two derivatization procedures, in situ acetylation and in tube silylation, and the results were compared with those obtained when the analytes were not derivatized. The proposed method, determining the analytes as acyl derivatives, was applied to analyze commercially canned beverages, as well as the filling liquids of canned vegetables, providing detection limits of between 4.7 and 12.5 ng L⁻¹, depending on the compound. The intraday and interday precisions were lower than 6% in terms of relative standard deviation. Recovery studies at two concentration levels, 0.1 and 1 μg L⁻¹, were performed providing recoveries in the 86-122% range. The samples analyzed contained higher concentrations of BPA than of the other analytes.

  8. Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

    DEFF Research Database (Denmark)

    Chiper, Alina Silvia; Chen, Weifeng; Mejlholm, Ole

    2011-01-01

    The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical...... emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A–X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three...

  9. Diameter control of gold nanoparticles synthesized in gas phase using atmospheric-pressure H2/Ar plasma jet and gold wire as the nanoparticle source: Control by varying the H2/Ar mixture ratio

    Science.gov (United States)

    Shimizu, Yoshiki

    2017-01-01

    This report describes diameter control of gold nanoparticles (AuNPs) during synthesis using an atmospheric-pressure H2/Ar plasma jet drive with pulse-modulated ultrahigh frequency, employing Au wire as the NP source material. During this process, where most of the AuNPs are regarded as formed through condensation from Au vapor derived by the Au wire etching, the mean diameter varied in the approximate range of 2-12 nm with H2 volume ratios up to 3.9%. In plasma diagnostics, results showed that the H2 volume ratio influences the plasma discharge behaviour, which affects the heat flux density flowed into the Au wire, and the atomic hydrogen concentration in the plasma. Both seemed to influence the etching rate of the Au wire per unit area, which is directly related to the concentration of Au vapor in the plasma. The concentration is one factor affecting the particle size evolution because of the collisions among vapor species in reaction field. Therefore, the AuNP size variation with the H2 volume ratio was discussed from the perspective of the etching rate of the Au wire at each H2 volume ratio.

  10. Diameter control of gold nanoparticles synthesized in gas phase using atmospheric-pressure H2/Ar plasma jet and gold wire as the nanoparticle source: Control by varying the H2/Ar mixture ratio

    Directory of Open Access Journals (Sweden)

    Yoshiki Shimizu

    2017-01-01

    Full Text Available This report describes diameter control of gold nanoparticles (AuNPs during synthesis using an atmospheric-pressure H2/Ar plasma jet drive with pulse-modulated ultrahigh frequency, employing Au wire as the NP source material. During this process, where most of the AuNPs are regarded as formed through condensation from Au vapor derived by the Au wire etching, the mean diameter varied in the approximate range of 2–12 nm with H2 volume ratios up to 3.9%. In plasma diagnostics, results showed that the H2 volume ratio influences the plasma discharge behaviour, which affects the heat flux density flowed into the Au wire, and the atomic hydrogen concentration in the plasma. Both seemed to influence the etching rate of the Au wire per unit area, which is directly related to the concentration of Au vapor in the plasma. The concentration is one factor affecting the particle size evolution because of the collisions among vapor species in reaction field. Therefore, the AuNP size variation with the H2 volume ratio was discussed from the perspective of the etching rate of the Au wire at each H2 volume ratio.

  11. Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Haq, Inam U.; Sabin, John R.

    2013-01-01

    Using an asymmetric-Lanczos-chain algorithm for the calculation of the coupled cluster linear response functions at the CCSD and CC2 levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule H2. Convergence with respect...

  12. Re-Evaluation of Ar-39 - Ar-40 Ages for Apollo Lunar Rocks 15415 and 60015

    Science.gov (United States)

    Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.

    2010-01-01

    We re-analyzed 39Ar-40Ar ages of Apollo lunar highland samples 15415 and 60015, two ferroan anorthosites analyzed previously in the 1970 s, with a more detailed approach and with revised decay constants. From these samples we carefully prepared 100-200 mesh mineral separates for analysis at the Noble Gas Laboratory at NASA-Johnson Space Center. The Ar-39-Ar-40 age spectra for 15415 yielded an age of 3851 +/- 38 Ma with 33-99% of Ar39 release, roughly in agreement with previously reported Ar-Ar ages. For 60015, we obtained an age of 3584 +/- 152 Ma in 23-98% of Ar39 release, also in agreement with previously reported Ar-Ar ages of approximately 3.5 Ga. Highland anorthosites like these are believed by many to be the original crust of the moon, formed by plagioclase floatation atop a magma ocean, however the Ar-Ar ages of 15415 and 60015 are considerably younger than lunar crust formation. By contrast, recently recovered lunar anorthosites such as Dhofar 489, Dhofar 908, and Yamato 86032 yield older Ar-Ar ages, up to 4.35 Ga, much closer to time of formation of the lunar crust. It follows that the Ar-Ar ages of the Apollo samples must have been reset by secondary heating, and that this heating affected highland anorthosites at both the Apollo 15 and Apollo 16 landing sites but did not affect lunar highland meteorites. One obvious consideration is that while the Apollo samples were collected from the near side of the moon, these lunar meteorites are thought to have originated from the lunar far side

  13. ArArCALC—software for 40Ar/ 39Ar age calculations

    Science.gov (United States)

    Koppers, Anthony A. P.

    2002-06-01

    ArArCALC is a Microsoft Excel ® 97-2000-XP application for performing calculations in 40Ar/ 39Ar geochronology. It is coded in Visual Basic for Applications and can be used under the Windows ® 95/98/NT/2000/ME/XP operating systems. ArArCALC provides an easy-to-use graphical interface for the calculation of age plateaus, total fusion ages and isochrons following the regression of 40Ar/ 39Ar mass spectrometry data. Results are stored in single Excel workbooks including nine different data tables and four different diagrams. Analytical, internal and external errors are calculated based on error propagation of all input parameters, analytical data and applied corrections. Finally, the age calculation results can be recalibrated with reference to the primary K-Ar standards (e.g. GA-1550, MMhb-1) in order to obtain more consistent absolute40Ar/ 39Ar age determinations. ArArCALC is distributed as freeware.

  14. Study on the Principle Mechanisms of Heat Transfer for Cryogenic Insulations: Especially Accounting for the Temperature-Dependent Deposition-Evacuation of the Filling Gas (Self-Evacuating Systems)

    Science.gov (United States)

    Geisler, Matthias; Vidi, Stephan; Ebert, Hans-Peter

    2016-11-01

    This study concentrates on the principles of heat transfer within cryogenic insulation systems, especially accounting for self-evacuating systems (deposition-evacuation of the filling gas). These principles allow the extrapolation to other temperatures, gases and other materials with the input of only a few experimentally derived or carefully estimated material properties. The type of gas (e.g. air or CO2) within the porous insulation material dominates the behaviour of the effective thermal conductivity during the cooldown of the cryogenic application. This is due to the specific temperature-dependent saturation gas pressure which determines the contribution of the gas conductivity. The selected material classes include powders, fibrous insulations, foams, aerogels and multilayer insulations in the temperature range of 20 K to 300 K. Novel within this study is an analytical function for the total and the mean thermal conductivity with respect to the temperature, type of gas, external pressure and material class of the insulation. Furthermore, the integral mean value of the thermal conductivity, the so-called mean thermal conductivity, is calculated for a mechanically evacuated insulation material and an insulation material evacuated by deposition-evacuation of the filling gas, respectively. This enables a comparison of the total thermal conductivity of cryogenic insulation materials and their applicability for a self-evacuating cryogenic insulation system.

  15. Determinação de volumes e pressões de balonetes de tubos traqueais insuflados com ar ambiente ou óxido nitroso Determinación de volúmenes y presiones de balones de tubos traqueales insuflados con aire ambiente u óxido nitroso Volume and pressure of tracheal tube cuffs filled with air or nitrous oxide

    Directory of Open Access Journals (Sweden)

    Ernesto Leonardo Cárpio Peña

    2004-06-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: A pressão exercida pelo balonete do tubo traqueal contra a parede da traquéia deve permitir fluxo capilar adequado e prevenir escapes de ar ou aspiração pulmonar. Esta pesquisa procurou determinar as variações de pressão do balonete insuflado com ar ambiente ou com óxido nitroso a 100%. MÉTODO: Trinta pacientes foram selecionados para receber anestesia geral balanceada com intubação orotraqueal. O balonete foi insuflado conforme critérios clínicos. As medidas de base foram realizadas após 15 minutos do início da anestesia com um manômetro aneróide calibrado em cm de H2O e forneceram os valores iniciais de pressão e volume. Os pacientes foram divididos em dois grupos: balonete reinsuflado com ar ambiente, grupo A, ou com óxido nitroso, grupo B. As medidas de pressão foram obtidas em intervalos até a primeira hora e os resultados comparados. RESULTADOS: Os grupos mostraram-se comparáveis para idade e sexo. Em ambos os grupos os valores basais médios para pressão foram próximos de 40 cmH2O com 8 ml de volume. No grupo com ar ambiente, as pressões aumentaram até 36 cmH2O em uma hora. No grupo de balonete insuflado com N2O, as pressões diminuíram abaixo de 20 cmH2O entre 20 e 30 minutos de anestesia. CONCLUSÕES: O uso de N2O a 100% para insuflação do balonete de sonda traqueal não constitui método seguro, acarretando progressiva perda da capacidade de vedação. O uso de ar ambiente promove aumento de volume e de pressão no balonete, aumentando possibilidade de lesão da mucosa traqueal.JUSTIFICATIVA Y OBJETIVOS: La presión ejercida por el balón del tubo traqueal contra la pared de la traquea debe permitir flujo capilar adecuado y prevenir escapes de aire o aspiración pulmonar. Esta pesquisa buscó determinar las variaciones de presión del balón insuflado con aire ambiente o con óxido nitroso a 100%. MÉTODO: Treinta pacientes fueron seleccionados para recibir anestesia general

  16. Revised error propagation of 40Ar/39Ar data, including covariances

    Science.gov (United States)

    Vermeesch, Pieter

    2015-12-01

    The main advantage of the 40Ar/39Ar method over conventional K-Ar dating is that it does not depend on any absolute abundance or concentration measurements, but only uses the relative ratios between five isotopes of the same element -argon- which can be measured with great precision on a noble gas mass spectrometer. The relative abundances of the argon isotopes are subject to a constant sum constraint, which imposes a covariant structure on the data: the relative amount of any of the five isotopes can always be obtained from that of the other four. Thus, the 40Ar/39Ar method is a classic example of a 'compositional data problem'. In addition to the constant sum constraint, covariances are introduced by a host of other processes, including data acquisition, blank correction, detector calibration, mass fractionation, decay correction, interference correction, atmospheric argon correction, interpolation of the irradiation parameter, and age calculation. The myriad of correlated errors arising during the data reduction are best handled by casting the 40Ar/39Ar data reduction protocol in a matrix form. The completely revised workflow presented in this paper is implemented in a new software platform, Ar-Ar_Redux, which takes raw mass spectrometer data as input and generates accurate 40Ar/39Ar ages and their (co-)variances as output. Ar-Ar_Redux accounts for all sources of analytical uncertainty, including those associated with decay constants and the air ratio. Knowing the covariance matrix of the ages removes the need to consider 'internal' and 'external' uncertainties separately when calculating (weighted) mean ages. Ar-Ar_Redux is built on the same principles as its sibling program in the U-Pb community (U-Pb_Redux), thus improving the intercomparability of the two methods with tangible benefits to the accuracy of the geologic time scale. The program can be downloaded free of charge from

  17. Dynamics of the spectral behaviour of an ultrashort laser pulse in an argon-gas-filled capillary discharge-preformed plasma channel

    Directory of Open Access Journals (Sweden)

    Sakai S.

    2013-11-01

    Full Text Available We have reported the argon plasma waveguide produced in an alumina (Al2O3 capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016  W/cm2. A one-dimensional magnetohydrodynamic (MHD code was used to evaluate the average degree of ionization of Ar in the preformed plasma channel. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell (PIC simulation under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  18. Effect of Different Filling Materials in Anammox Bacteria Enrichment

    Directory of Open Access Journals (Sweden)

    Dilek ÖZGÜN

    2012-12-01

    Full Text Available Purpose: Anaerobic ammonium oxidation (Anammox is a process that ammonium as electron donor is oxidized to nitrogen gas using nitrite as electron acceptor. Compared to conventional nitrification-denitrification processes, this process is used less oxygen and no organic material (methanol, glucose. However, the slow growth rate of Anammox bacteria (11-30 days is disadvantages. Therefore, batch reactors have been carried out in these bacteria enrichment. In this study continuously operated upflow anaerobic sludge reactor (UASB using different filling materials disposing of sensitive and slow-growing Anammox bacteria out of the system is purposed. Design and Methods: System is operated up-flow column reactor at 2 days hydraulic retention time (HRT in 45 days. In this study, ceramic stones and Linpor filling material are used. Using synthetic wastewater containing ammonium and nitrite, Ar/CO2 anaerobic conditions (95/5% supplied with gas. System is operated at a temperature 253 C in UASB. Temperature, pH, ammonia-nitrogen and nitrite nitrogen are measured. Results: Both filling material reactors are operated in 45 days. Ceramic stones filling reactor is observed quickly reaches 90% were used reactor ammonium removal. The ammonium nitrogen removal was slower in Linpor filling materials reactor. Nitrite removal is reached up to 90% in both the reactor. When compared to the stoichiometric equation in Linpor was composed of large amounts of nitrate. At the end of 25 days the results were similar to ceramic stone filling reactor with Linpor filling material reactors. Conclusions and Original Value: Anammox process as from nitrogen removal processes was discovered in 1995. Anammox bacteria that make up this process due to very low growth rates of microbial bacteria in the system must be kept in the system. Most of the studies in the literature, these bacteria enrichment stage is started instead of a continuous batch reactor system. In this study

  19. Numerical simulation on gas explosions in compression compartment of gas filling station%加气站压缩机间气体爆炸数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    吴运逸; 雷海丽

    2013-01-01

    加气站压缩机间安全设计时,需要评估内部气体爆炸危害,确定爆炸能量和影响因素。采用CFD技术,建立加气站压缩机间三维模型,模拟不同点火源位置、泄压板不同泄压压力和重量下,压缩机间气体爆炸时的爆炸压力及火焰传播行为。结果表明点火源位置以及泄压参数是影响加气站压缩机间气体爆炸的重要因素;点火源位置距离压缩机间放空位置越近,爆炸压力越小;对于泄压参数,爆炸压力与泄压板开启压力和重量之间均为正比关系。为减缓压缩机间内的气体爆炸危害,需要合理布置点火源位置,选择容重轻、泄压压力小的泄压材料,并同时需要考虑爆炸导致的物体破碎危害以及火焰次生灾害。%The hazards of gas explosion in compression compartment should be assessed , and explosion energy as well as influence factors should be determined for the safety design of compression compartment in gas filling sta -tion.In this study, numerical simulation was adopted to build 3D model of compression compartment and simulate gas explosion pressure and flame propagation behavior under different ignition point location , open-pressure and weight of relief panels .The results showed that the ignition point location relative to the location of the vent opening and relief panel ’ s characteristics is very important for gas explosion in compression compartment .The nearer the ignition point location is away from the venting opening location , the smaller the caused explosion pressure will be . For the relief panel , explosion pressure is proportional with the open-pressure and the weight of relief panel .Be-sides the rational distribution of ignition source and the adoption of relief panel with less unit weight and relief pres -sure, the crushing material damage and secondary hazard of flame should also be noticed in order to mitigate the hazard of gas explosion .

  20. Indium-tin oxide thin films deposited at room temperature on glass and PET substrates: Optical and electrical properties variation with the H{sub 2}–Ar sputtering gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Álvarez-Fraga, L.; Jiménez-Villacorta, F.; Sánchez-Marcos, J.; Andrés, A. de; Prieto, C., E-mail: cprieto@icmm.csic.es

    2015-07-30

    Highlights: • ITO deposition on glass and PET at room temperature by using H. • High transparency and low resistance is obtained by tuning the H. • The figure of merit for ITO films on PET becomes maximal for thickness near 100 nm. - Abstract: The optical and electrical properties of indium tin oxide (ITO) films deposited at room temperature on glass and polyethylene terephthalate (PET) substrates were investigated. A clear evolution of optical transparency and sheet resistance with the content of H{sub 2} in the gas mixture of H{sub 2} and Ar during magnetron sputtering deposition is observed. An optimized performance of the transparent conductive properties ITO films on PET was achieved for samples prepared using H{sub 2}/(Ar + H{sub 2}) ratio in the range of 0.3–0.6%. Moreover, flexible ITO-PET samples show a better transparent conductive figure of merit, Φ{sub TC} = T{sup 10}/R{sub S}, than their glass counterparts. These results provide valuable insight into the room temperature fabrication and development of transparent conductive ITO-based flexible devices.

  1. Space-filling polyhedral sorbents

    Science.gov (United States)

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  2. Strong magnetism observed in carbon nanoparticles produced by the laser vaporization of a carbon pellet in hydrogen-containing Ar balance gas.

    Science.gov (United States)

    Asano, Hirohito; Muraki, Susumu; Endo, Hiroki; Bandow, Shunji; Iijima, Sumio

    2010-08-25

    Nanometer-scale carbon particles driven by the pulsed-laser vaporization of pelletized pure carbon powder at 1000 °C in a hydrogen-containing environment show anomalous magnetism like a superparamagnet, while the sample prepared in 100% of Ar does not show such magnetism. The observed magnetism was unchanged over months in the ambient. The structure of this nanomaterial resembles the foam of a laundry detergent and transmission electron microscopy indicates a clear corrugated line contrast. On the other hand, a sample without strong magnetism does not give such an image contrast. The x-ray diffraction pattern coincides with that of graphite and no other peak is detected. Thermogravimetry indicates that all samples completely burn out up to approx. 820 °C and no material remains after combustion, indicating that the sample does not contain impurity metals. Magnetization is easily saturated by ∼10,000 G at 280 K with no hysteresis, but the hysteresis appears at 4.2 K. This phenomenon is explained by introducing a crystalline anisotropy which restricts the motion of the magnetic moment and stabilizes the remnant magnetization at zero magnetic field. Magnitudes of the saturation magnetization are in the range of 1-5 emu G g(-1) at 4.2 K, which correspond to 0.002-0.01 Bohr magneton per carbon atom. This concentration may be increased by ten times or more, because only about 4-10% of particles have a magnetic domain in the present samples.

  3. Two-dimensional electron gas at surfaces of (001), (110), and (111) oriented SrTiO3 induced by Ar+-irradiation

    Science.gov (United States)

    Miao, Ludi; Du, Renzhong; Yin, Yuewei; Li, Qi

    2015-03-01

    Two-dimensional electron gases (2DEGs) at transition metal oxide surfaces and interfaces have attracted much attention due to their fascinating exotic properties such as superconductivity, large magneto-resistance (MR), and ferromagnetism. We have created 2DEGs at the surfaces of (001), (110), and (111) oriented SrTiO3 (STO) by Ar+-irradiation and measured their transport properties. The 2DEGs exhibit a fully metallic behavior with the 2D charge carrier density around 2 ×1014 cm-2 and the mobility as large as 5500 cm2V-1s-1 at low temperatures, which is tunable by electric fields applied through STO back gates. We have measured MR anisotropy of the 2DEGs at surfaces of STO with all orientations. We observed combinations of two types of components in their anisotropic MR at low temperatures. While the first type is an STO-orientation-independent two-fold component results from the Lorentz force effect, the second type shows stark differences between these 2DEGs as a consequence of distinct Fermi surface symmetries with different STO orientations. Indeed, it is four-fold for STO (001), two-fold for STO (110) and six-fold for STO (111), respectively.

  4. METAL INERT GAS WELDING OF 2519-T87 HIGH STRENGTH ALUMINUM ALLOY

    Institute of Scientific and Technical Information of China (English)

    XU Lianghong; TIAN Zhiling; ZHANG Xiaomu; PENG Yun

    2007-01-01

    20 mm thick plates of 2519-T87 high strength aluminum alloy have been welded. The effects of the compositions of filier wires, the heat input and the compositions of shielding gas on the mechanical properties and microstructure of the welded joint have been investigated. The results indicate that finer microstructure, better mechanical properties and higher value of hardness of HAZ can be obtained by using lower heat input. The use of Ar/He mixed shielding gas has several advantages over pure Ar shielding gas. With the increase of the proportion of He in the mixed shielding gas, the grain size of the weld metal as well as porosity susceptibility decreases. When the volume ratio of He to Ar reaches 7:3, the porosity and the grain size of weld metal reach the minimum, and the porosity can be further reduced by filling some CO2.

  5. About Dental Amalgam Fillings

    Science.gov (United States)

    ... Medical Procedures Dental Devices Dental Amalgam About Dental Amalgam Fillings Share Tweet Linkedin Pin it More sharing ... I have my fillings removed? What is dental amalgam? Dental amalgam is a dental filling material used ...

  6. Spatial evaluation of Ar-systematics in rocks from the British Channel Islands: a UV laserprobe Ar/Ar study of excess 40Ar

    Science.gov (United States)

    Schwenzer, S. P.; Sherlock, S.; Kelley, S. P.

    2010-12-01

    includes sericitization of the feldspars and chloritization of biotite. Ar-Ar investigations were carried out using high spatial resolution UV laser ablation gas release in combination with a NU instruments Noblesse gas mass spectrometer. This sensitive instrumentation allows for a spatial resolution of 80 to 140 µm spot size. Detailed Ar-Ar analysis shows large variability of ages and also correlation with K and Ca content of the spot (measureable as 37Ar, and 39Ar after irradiation). In quartz in some of the samples there is large amounts of excess 40Ar accompanied by high 38Ar/39Ar and low to non-measurable 37Ar concentrations. This indicates the presence of chlorine and excess 40Ar; and thus fluid inclusions in those quartz crystals may be the host for excess 40Ar. Our preliminary results give insights into the behaviour of the Ar system during and after emplacement of igneous rocks from the Cadomian Belt, and the interaction of different reservoirs within the rocks.

  7. Primary production and carbon export rates across the subpolar N. Atlantic Ocean basin based on triple oxygen isotope and dissolved O2 and Ar gas measurements

    Science.gov (United States)

    Quay, P.; Stutsman, J.; Steinhoff, T.

    2012-06-01

    Gross photosynthetic O2 production (GOP) rates in the subpolar North Atlantic Ocean were estimated using the measured isotopic composition of dissolved oxygen in the surface layer on samples collected on nine transits of a container ship between Great Britain and Canada during March 2007 to June 2008. The mean basin-wide GOP rate of 226 ± 48 mmol O2 m-2 d-1 during summer was double the winter rate of 107 ± 41 mmol O2 m-2 d-1. Converting these GOP rates to equivalent 14C-based PP (14C-PPeqv) yielded rates of 1005 ± 216 and 476 ± 183 mg C m-2 d-1 in summer and winter, respectively, that generally agreed well with previous 14C-based PP estimates in the region. The 14C-PPeqv estimates were 1-1.6× concurrent satellite-based PP estimates along the cruise track. A net community production rate (NCP) of 87 ± 12 mmol O2 m-2 d-1 (62 ± 9 mmol C m-2 d-1) and NCP/GOP of 0.35 ± 0.06 in the mixed layer was estimated from O2/Ar and 17Δ measurements (61°N 26°W) during spring bloom conditions in May 2008. Contrastingly, a much lower long-term annual mean NCP or organic carbon export rate of 2.8 ± 2.7 mol C m-2 yr-1 (8 ± 7 mmol C m-2 d-1) and NCP/GOP of 0.07 ± 0.06 at the winter mixed layer depth was estimated from 15 years of surface O2 data in the subpolar N. Atlantic collected during the CARINA program.

  8. Gas-phase and Ar-matrix SQM scaling factors for various DFT functionals with basis sets including polarization and diffuse functions.

    Science.gov (United States)

    Fábri, Csaba; Szidarovszky, Tamás; Magyarfalvi, Gábor; Tarczay, György

    2011-05-12

    Scaling factors for Pulay's scaled quantum mechanical (SQM) scheme have been determined for four different widely used DFT functionals (PBE, B3LYP, B3PW91, and M06-2X) and for two basis sets (6-31++G** and aug-cc-pVTZ) by fitting computed results to 347 fundamental experimental vibrational frequencies of 33 molecules. Measurements in the gas phase and in solid argon matrices were used independently in the fitting procedure in order to provide a simple method of estimating matrix shifts. The accuracy of the new scaling factors is demonstrated on test molecules including hydrogen-bonded systems and molecules containing chlorine and sulfur atoms.

  9. Study of laser-generated debris free x-ray sources produced in a high-density linear Ar, Kr, Xe, Kr/Ar and Xe/Kr/Ar mixtures gas jets by 2 ω, sub-ps LLNL Titan laser

    Science.gov (United States)

    Kantsyrev, V. L.; Schultz, K. A.; Shlyaptseva, V. V.; Safronova, A. S.; Cooper, M. C.; Shrestha, I. K.; Petkov, E. E.; Stafford, A.; Moschella, J. J.; Schmidt-Petersen, M. T.; Butcher, C. J.; Kemp, G. E.; Andrews, S. D.; Fournier, K. B.

    2016-10-01

    The study of laser-generated debris-free x-ray sources in an underdense plasma produced in a high-density linear gas-puff jet was carried out at the LLNL Titan laser (2 ω, 45 J, sub-ps) with an intensity in the 10 um focal spot of 7 x 1019 W/cm2. A linear nozzle with a fast valve was used for the generation of a clusters/gas jet. X-ray diagnostics for the spectral region of 0.7 - 9 keV include: two spectrometers and pinhole cameras, and 3 groups of fast filtered detectors. Electron beams were measured with the EPPS magnetic spectrometer (>1 MeV) and Faraday cups (>72 keV). Spectralon/spectrometer devices were also used to measure absorption of laser radiation in the jets. New results were obtained on: anisotropic generation of x-rays (laser to x-ray conversion coefficient was >1%) and characteristics of laser-generated electron beams; evolution of x-ray generation with the location of the laser focus in a cluster-gas jet, and observations of a strong x-ray flash in some focusing regimes. Non-LTE kinetic modeling was used to estimate plasma parameters. UNR work supported by the DTRA Basic Research Award # HDTRA1-13-1-0033. Work at LLNL was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  10. Modeling of mould cavity filling process with cast iron in Lost Foam method Part 3. Mathematical model – pressure inside the gas gap

    Directory of Open Access Journals (Sweden)

    T. Pacyniak

    2008-08-01

    Full Text Available In this work mathematical model describing changes of pressure inside the gas gap was shown during manufacturing gray cast iron castings with use of lost foam process. Authors analyzed the results of numerical simulation enclosing influence of foamed polystyrene pattern density, permeability and thickness of refractory coating on pressure changes in the gap. Studies have shown, that all these parameters have significant influence on pressure inside the gas gap.

  11. Raman-Free, Noble-Gas-Filled Photonic-Crystal Fiber Source for Ultrafast, Very Bright Twin-Beam Squeezed Vacuum

    Science.gov (United States)

    Finger, Martin A.; Iskhakov, Timur Sh.; Joly, Nicolas Y.; Chekhova, Maria V.; Russell, Philip St. J.

    2015-10-01

    We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagome-style photonic-crystal fiber. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ˜2500 photons per mode. The ultra-broadband (˜50 THz ) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes. The presented source outperforms all previously reported squeezed-vacuum twin-beam sources in terms of brightness and low mode content.

  12. Raman-Free, Noble-Gas-Filled Photonic-Crystal Fiber Source for Ultrafast, Very Bright Twin-Beam Squeezed Vacuum.

    Science.gov (United States)

    Finger, Martin A; Iskhakov, Timur Sh; Joly, Nicolas Y; Chekhova, Maria V; Russell, Philip St J

    2015-10-02

    We report a novel source of twin beams based on modulational instability in high-pressure argon-filled hollow-core kagome-style photonic-crystal fiber. The source is Raman-free and manifests strong photon-number correlations for femtosecond pulses of squeezed vacuum with a record brightness of ∼2500 photons per mode. The ultra-broadband (∼50  THz) twin beams are frequency tunable and contain one spatial and less than 5 frequency modes. The presented source outperforms all previously reported squeezed-vacuum twin-beam sources in terms of brightness and low mode content.

  13. MALATANG: MApping the dense moLecular gAs in the sTrongest stAr-formiNg Galaxies

    Science.gov (United States)

    Gao, Yu; Zhang, Zhiyu; Greve, Thomas; MALATANG Team

    2017-01-01

    The MALATANG Large Program is a 390 hr campaign, using the heterodyne array HARP on the JCMT to map theHCN and HCO+ J = 4 - 3 line emission in 23 of the nearest IR-brightest galaxies beyond the Local Group. Theobservations will reach a sensitivity of 0.3 K km/s (~ 4.5 x 10^6 Msun) at linear resolutions of 0.2-2.8kpc. It is thefirst survey to systematically map the distribution of dense molecular gas out to large galactocentric distances in a statisticallysignificant sample of nearby galaxies. MALATANG will bridge the gap, in terms of physical scale and luminosity,between extragalactic (i.e., galaxy-integrated) and Galactic (i.e., single molecular clouds) observations. A primarygoal of the survey is to delineate for the first time the distributed dense gas star-formation relations, as traced by theHCN and HCO+ J = 4-3, on scales of ~1kpc across our targets. Exploring the behaviour of these star-formationrelations in low surface density regions found in the disks as well as in the nuclear regions where surface densitiesare high, will shed new light on whether such environments are host to fundamentally different star-formation modes.The MALATANG data products of resolved HCN and HCO+ J = 4-3 maps of 23 IR-bright local galaxies, will beof great value to the extragalactic community and, in and of themselves, carry significant legacy value. At the moment,about 50% (~195hrs) of the 390hrs of time allocated to MALATANG has been observed. We here show somevery preliminary results as well after introducing our project.

  14. Ars Himera / Irina Lobanova

    Index Scriptorium Estoniae

    Lobanova, Irina

    2003-01-01

    Iseloomustatakse praegust aega ja moodsat kunsti: valitseb vastutustundetus ja ebainimlikkus. Näited - professor von Hageni "Korpwelten" ja uusim kunstinähtus Ars Chimaera - eksponeerimise eesmärgil surrogaatsete elusolendite saamise kunst

  15. Analysis Method for Permeability Characteristics of Gas-filled Coal Based on Considering Adsorption Effect%基于考虑吸附作用影响的含瓦斯煤渗透特性分析方法

    Institute of Scientific and Technical Information of China (English)

    张志刚; 胡千庭

    2015-01-01

    基于前期的实验研究成果,得出考虑吸附作用影响的瓦斯渗流方程,在此基础上,建立了钻孔稳定流动状态下的瓦斯渗流模型,并采用数学物理的方法推导出钻孔单向稳定流状态下的解析解,获得了基于考虑吸附作用影响的含瓦斯煤渗透特性分析方法,为研究钻孔瓦斯涌出规律提供了技术支撑。%A gas seepage equation with considering the adsorption effect was obtained according to the earlier experimental results, on this basis a gas seepage model under stable hole flow state was established, the analytical solution under the condition of the hole unidirectional stable flow was derived by the method of mathematical physics, and based on considering the adsorption effect, the analysis method for the permeability characteristics of gas-filled coal was obtained, all of these provided technical support for the research on gas emission law of boreholes.

  16. Anionic chemistry of noble gases: formation of Mg-NG (NG = Xe, Kr, Ar) compounds under pressure.

    Science.gov (United States)

    Miao, Mao-Sheng; Wang, Xiao-Li; Brgoch, Jakoah; Spera, Frank; Jackson, Matthew G; Kresse, Georg; Lin, Hai-Qing

    2015-11-11

    While often considered to be chemically inert, the reactivity of noble gas elements at elevated pressures is an important aspect of fundamental chemistry. The discovery of Xe oxidation transformed the doctrinal boundary of chemistry by showing that a complete electron shell is not inert to reaction. However, the reductive propensity, i.e., gaining electrons and forming anions, has not been proposed or examined for noble gas elements. In this work, we demonstrate, using first-principles electronic structure calculations coupled to an efficient structure prediction method, that Xe, Kr, and Ar can form thermodynamically stable compounds with Mg at high pressure (≥125, ≥250, and ≥250 GPa, respectively). The resulting compounds are metallic and the noble gas atoms are negatively charged, suggesting that chemical species with a completely filled shell can gain electrons, filling their outermost shell(s). Moreover, this work indicates that Mg2NG (NG = Xe, Kr, Ar) are high-pressure electrides with some of the electrons localized at interstitial sites enclosed by the surrounding atoms. Previous predictions showed that such electrides only form in Mg and its compounds at very high pressures (>500 GPa). These calculations also demonstrate strong chemical interactions between the Xe 5d orbitals and the quantized interstitial quasiatom (ISQ) orbitals, including the strong chemical bonding and electron transfer, revealing the chemical nature of the ISQ.

  17. Effect of Na Environment on growth rate of grain and nucleation of precipitate in F/M steel cladding under Sodium and Ar-gas environment at 650 .deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Yong; Kim, Ji Hyun [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Shin, Sang Hun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    During the design life time (30 to 60 years), the cladding and structural materials are exposed to liquid sodium and aged at the designed operation temperature. When cladding and structural materials exposed to high temperature liquid sodium, the constituents of the components dissolve and exist as various compounds. This can accelerate the dissolution of components into coolant or disrupt flow of coolant with cumulated obstacle in loop. This change can cause a degradation of mechanical strength of structure material and thermal efficiency of UCFR. Therefore, the thermochemical reaction research, on effects of liquid sodium on ferrite/martensite steel for a long time, should additionally be performed. The goal of this study is to investigate growth and nucleation of precipitates of ferrite/martensite steels in liquid sodium and its effect on grain growth. There are many changes such as Cr depletion, decarburization, segregation, precipitate and oxidation, affecting into microstructural evolution of the steels. In a specific procedure, the micro-structure and the surface phenomenon of ferrite/martensite steels that are exposed in liquid sodium at high temperature by using scanning electron microscope (SEM) and transmission electron microscope (TEM) have been investigated. After investigating precipitates formed at surface on liquid sodium and Ar-gas environments, the precipitates' Gibbs free energy is calculated with enthalpy and entropy included in the precipitates. Finally, the calculated values with diffusivity of components will become reason why the phases have different tendency on the growth rate of precipitates. As analyzing the chemical composition by TEM images, the correlation is investigated with supplementary materials. When Gr.92 is exposed to sodium containing oxygen, oxide is formed and there are depletion of Cr and presumably decarburization into sodium. So, the amount of M{sub 23}C{sub 6} is decreased. At Ar-gas environment, there is no

  18. Intermolecular polarizabilities in H{sub 2}-rare-gas mixtures (H{sub 2}–He, Ne, Ar, Kr, Xe): Insight from collisional isotropic spectral properties

    Energy Technology Data Exchange (ETDEWEB)

    Głaz, Waldemar, E-mail: glaz@kielich.amu.edu.pl; Bancewicz, Tadeusz [Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Godet, Jean-Luc [Laboratoire de photonique d’Angers, Université d’Angers, 2 boulevard Lavoisier, 49045 Angers (France); Gustafsson, Magnus [Department of Chemistry and Molecular Biology, University of Gothenburg, SE 412 96 Gothenburg (Sweden); Maroulis, George; Haskopoulos, Anastasios [Department of Chemistry, University of Patras, GR-26500 Patras (Greece)

    2014-08-21

    The report presents results of theoretical and numerical analysis of the electrical properties related to the isotropic part of the polarizability induced by interactions within compounds built up of a hydrogen H{sub 2} molecule and a set of noble gas atoms, Rg, ranging from the least massive helium up to the heaviest xenon perturber. The Cartesian components of the collisional polarizabilities of the H{sub 2}–Rg systems are found by means of the quantum chemistry methods and their dependence on the intermolecular distance is determined. On the basis of these data, the spherical, symmetry adapted components of the trace polarizability are derived in order to provide data sets that are convenient for evaluating collisional spectral profiles of the isotropic polarized part of light scattered by the H{sub 2}–Rg mixtures. Three independent methods of numerical computing of the spectral intensities are applied at room temperature (295 K). The properties of the roto-translational profiles obtained are discussed in order to determine the role played by contributions corresponding to each of the symmetry adapted parts of the trace polarizability. By spreading the analysis over the collection of the H{sub 2}–Rg systems, evolution of the spectral properties with the growing masses of the supermolecular compounds can be observed.

  19. Singularity links with exotic Stein fillings

    OpenAIRE

    Özbağcı, Burak; Akhmedov, Anar

    2012-01-01

    arXiv:1206.2468v3 [math.GT] 14 May 2014 SINGULARITY LINKS WITH EXOTIC STEIN FILLINGS ANAR AKHMEDOV AND BURAK OZBAGCI ABSTRACT. In [4], it was shown that there exist infinitely many contact Seifert fibered 3-manifolds each of which admits infinitely many exotic (homeomorphic but pairwise non-diffeomorphic) simply-connected Stein fillings. Here we extend this result to a larger set of contact Seifert fibered 3-manifolds with many singular fibers and observe that these 3- ma...

  20. Supercontinuum generation in the vacuum ultraviolet through dispersive-wave and soliton-plasma interaction in a noble-gas-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Ermolov, A.; Mak, K. F.; Frosz, M. H.; Travers, J. C.; Russell, P. St. J.

    2015-09-01

    We report on the generation of a three-octave-wide supercontinuum extending from the vacuum ultraviolet (VUV) to the near infrared, spanning at least 113-1000 nm (i.e., 11 -1.2 eV ), in He-filled hollow-core kagome-style photonic crystal fiber. Numerical simulations confirm that the main mechanism is an interaction between dispersive-wave emission and plasma-induced blue-shifted soliton recompression around the fiber zero dispersion frequency. The VUV part of the supercontinuum, the modeling of which proves to be coherent and possesses a simple phase structure, has sufficient bandwidth to support single-cycle pulses of 500 asec duration. We also demonstrate, in the same system, the generation of narrower-band VUV pulses through dispersive-wave emission, tunable from 120 to 200 nm with efficiencies exceeding 1 % and VUV pulse energies in excess of 50 nJ.

  1. Supercontinuum generation and tunable ultrafast emission in the vacuum ultraviolet using noble-gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Ermolov, Alexey; Frosz, Michael H; Travers, John C; Russell, Philip St J

    2015-01-01

    We report on the generation of a three-octave supercontinuum extending from the vacuum ultraviolet (VUV) to the near-infrared, spanning at least 113 to 1000 nm (i.e., 11 to 1.2 eV), in He-filled hollow-core kagome-style photonic crystal fiber. The same system also permits generation of narrower-band VUV radiation tunable from 113 to 200 nm with efficiencies exceeding 1% and VUV pulse energies in excess of 50 nJ. Modeling confirms that the mechanism involves soliton self-compression to sub-femtosecond pulse durations, dispersive-wave emission and the plasma-induced soliton self-frequency blue-shift. The bandwidth of the generated VUV light, which modeling shows to be coherent, is sufficient to support 500 as single-cycle pulses.

  2. Tracking fluid action in Little Sark Pluton (Channel Islands, UK): a UV laserprobe Ar/Ar study of excess 40Ar

    Science.gov (United States)

    Schwenzer, S. P.; Schwanethal, J.; Tindle, A. G.; Kelley, S. P.; Sherlock, S. C.

    2011-12-01

    Little Sark pluton (Channel Islands, UK) is a weakly to moderately deformed pluton of quartz diorite composition. Zircon from Little Sark has been dated as 611.4(+2.1/-1.3) Ma [Miller et al. 1991, Tectonophysics, 312], whereas titanite has an age of 606.2±0.6 Ma. Hornblende yields an Ar-Ar age of 606.4±3.4 Ma [Dallmeyer et al., 1991, J. Geol. Soc. London 148]. The rocks show evidence for post-magmatic hydrous alteration including chloritisation of biotite, and sericite formation in feldspar. We investigated the alteration in order to understand its influence on the Ar-Ar system. Detailed petrographic investigations of two samples indicate different deformation levels - S1, (less deformed), and S2 (more deformed). The feldspar is andesine to oligoclase in composition, but contains K-rich areas with patchy and sometimes cleavage guided sericitization. Mafic minerals include hornblende and biotite (the latter partially chloritized). Ar-Ar investigations were carried out using high spatial resolution UV laser ablation gas release in combination with a Nu instruments Noblesse gas mass spectrometer using spots of 80 to 140 μm diameter. Mafic minerals in S1 have highly variable 38Ar/39Ar and 37Ar/39Ar ratios and unusually high atmospheric contents for such old samples, possibly reflecting the presence of fluid inclusions associated with the sericite, particularly in the feldspar. The apparent ages in their entirety range from 429 to 668 Ma. Hornblende yields homogeneous apparent ages, whereas the younger and older ages are measured in both micas and feldspars, whose apparent ages range from 245-670 Ma. The modal age for feldspar is around 400-450 Ma, but this may not have geological meaning. Sample S2 shows many of the same features as S1. Mafic minerals span a slightly smaller age range and feldspars display apparent ages of ~245-645 Ma with a mode around 480 Ma. The alteration of both samples appears to have been accompanied by the introduction of 40Ar-rich fluids

  3. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  4. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  5. Practical reactor production of {sup 41}Ar from argon clathrate

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, J.R. E-mail: jmercer@pharmacy.ualberta.ca; Duke, M.J.M.; McQuarrie, S.A

    2000-06-01

    The radionuclide {sup 41}Ar has many ideal properties as a gas flow tracer. However, the modest cross-section of {sup 40}Ar for thermal neutron activation makes preparation of suitable activities of {sup 41}Ar technically difficult particularly for low flux reactors. Argon can however be trapped in a molecular complex called a clathrate that can then be irradiated. We prepared argon clathrate and explored its irradiation and stability characteristics. Argon clathrate can be used to provide gigabecquerel quantities of {sup 41}Ar even with low power reactors.

  6. The emission spectra of Ar, Kr and Xe + TEA

    Science.gov (United States)

    Suzuki, Masayo; Strock, Pierre; Sauli, Fabio; Charpak, Georges

    1987-03-01

    The emission spectra of Ar, Kr and Xe + 6% TEA gas mixtures are measured by using a single wire proportional counter as the emission source. Asymmetric emission bands are observed in the range of 270 to 350 nm, which can be attributed to the radiative deexcitation of excited TEA molecules. For the practical application of optical readout of avalanche chambers, the Ar + 2.0% TEA + 20% isobutane gas mixture is also examined, and nearly the same emission band is observed.

  7. Getting a prescription filled

    Science.gov (United States)

    ... are located inside of a grocery or large "chain" store. It is best to fill all prescriptions ... be used for long-term medicines and medical supplies. The website should have clear directions for filling ...

  8. Efeitos do pneumoperitônio com ar e CO2 na gasometria de suínos Effects of CO2 and air pneumoperitoneum on blood gas changes in pigs

    Directory of Open Access Journals (Sweden)

    Silvio Luis da Silveira Lemos

    2003-10-01

    Full Text Available OBJETIVO: O pneumoperitônio produz várias alterações na fisiologia humana. Algumas destas alterações, como hipercapnia e acidose, dependem ou são agravadas com o uso de CO2, tendo maior repercussão em pacientes com problema cardio-respiratório. A necessidade de uma melhor alternativa para insuflação da cavidade; a observação de que as cirurgias abertas, assim como as laparoscópicas com suspensão mecânica, são realizadas na presença de Ar ambiente; e a escassez de trabalhos testando o Ar em substituição ao CO2 para insuflação da cavidade, foram motivos para a realização deste trabalho. MÉTODOS: Vinte (0 suínos anestesiados foram submetidos a pneumoperitônio com 1 hora de duração. Os animais foram distribuídos em 4 grupos de 5 animais: Grupo A1 - Pneumoperitônio de Ar a 10 mmHg; Grupo A - Pneumoperitônio de Ar a 16 mmHg; Grupo B1 - Pneumoperitônio de CO2 a 10 mmHg; Grupo B - Pneumoperitônio de CO2 a 16 mmHg. O pneumoperitônio foi realizado pela técnica aberta com trocater de Hasson. Através de um cateter venoso central colhe-se amostra de sangue para exame de gasometria em 3 momentos. RESULTADOS: A análise da gasometria venosa não revelou alterações significativas entre os grupos em relação a PaO2 e a saturação do O2. Nos Grupos A1, A e B1 não foram observadas alterações no equilíbrio ácido-básico. No Grupo B após uma hora de pneumoperitônio houve nítida tendência a hipercapnia e acidose. CONCLUSÃO: O ar, com a técnica aberta de pneumoperitônio foi uma opção segura para insuflação de cavidade em procedimentos laparoscópicos diagnósticos de suínos.PURPOSE: The pneumoperitoneum causes several physiological alterations in humans. Some of these alterations, as hypercapnia and acidosis, are dependent on the use of CO2 or aggravated by its use, and affects mainly the patients with cardiopulmonary problems. The need for a better alternative of cavity insufflation; the observation that open

  9. 多层结构船舶机舱火灾烟气充填数值计算%Numerical calculation of fire flue gas filling in ship engine room with multilayer structure

    Institute of Scientific and Technical Information of China (English)

    王亮; 苏石川

    2011-01-01

    Based on large eddy simulation, the filtered balance equations and the Smagorinsky subgrid-scale model of fire in ship engine room with multilayer structure were established. Second-order finite difference method was used to disperse spatial variables, explicit second-order predictor-corrector scheme method was used to disperse flow variables, and explicit second-order Runge-Kutta method was used to disperse time variables. Velocity field, temperature field, flue gas concentration and the height of flue gas layer were solved respectively, and the change laws of fire flue gas filling in ship engine rooms with multilayer structure and monolayer structure were analyzed. Analysis result shows that the spread speed and area of flue gas in multilayer structure are greater than those in monolayer structure. When ship engine room with monolayer structure is full of flue gas, filling time is 200 s, while the filling time of ship engine room with multilayer structure is 1 500 s. Under two structures, the temperatures of cold air layer and hot flue gas layer almost increase at first then decrease, the maximum temperatures at the tops of ship engine rooms are 170 ℃, 250 ℃ respectively, however, the maximum temperatures at the bottoms of ship engine rooms are 175 ℃, 100 ℃ respectively. 3 tabs, 5 figs, 15 refs.%应用大涡模拟技术,建立了多层结构船舶机舱火灾的过滤平衡方程组与Smagorinsky亚格子模型。采用二阶有限差分法对空间变量进行离散,采用显式二阶预估校中法对流动变量进行离散,采用显式二阶Runge-Kutta法对时间变量进行离散,分别求解了速度场、温度场、烟气浓度与烟气层高度,比较了多层结构与单层结构船舶机舱火灾烟气充填变化规律。分析结果表明:多层结构烟气蔓延速度与面积大于单层结构烟气蔓延速度与面积;在单层结构中,烟气在200s时快速充满整个舱室,在多层结构中,烟气在1500s

  10. Measurement of the attenuation length of argon scintillation light in the ArDM LAr TPC

    CERN Document Server

    Calvo, J; Crivelli, P; Daniel, M; DiLuise, S; Gendotti, A; Horikawa, S; Molina-Bueno, L; Montes, B; Mu, W; Murphy, S; Natterer, G; Ngyuen, K; Periale, L; Quan, Y; Radics, B; Regenfus, C; Romero, L; Rubbia, A; Santorelli, R; Sergiampietri, F; Viant, T; Wu, S

    2016-01-01

    We report on a measurement of the attenuation length for the scintillation light in the tonne size liquid argon target of the ArDM dark matter experiment. The data was recorded in the first underground operation of the experiment in single-phase operational mode. The results were achieved by comparing the light yield spectra from 39-Ar and 83m-Kr to a description of the ArDM setup with a model of full light ray tracing. A relatively low value close to 0.5 m was found for the attenuation length of the liquid argon bulk to its own scintillation light. We interpret this result as a presence of optically active impurities in the liquid argon which are not filtered by the installed purification systems. We also present analyses of the argon gas employed for the filling and discuss cross sections in the vacuum ultraviolet of various molecules in respect to purity requirements in the context of large liquid argon installations.

  11. ``Smoking From The Same Pipe": Developement of an 40Ar/39Ar Datting Intercalibration PIpette System (Invited)

    Science.gov (United States)

    Turrin, B. D.; Swisher, C. C.; Deino, A.; Hemming, S. R.; Hodges, K.; Renne, P. R.

    2010-12-01

    The precision and accuracy of Ar isotope ratio measurements is one of the main limiting factors in the uncertainties of an 40Ar/39Ar age. Currently, it is relatively common to measure Ar isotopic ratios to a precision of 1-2‰ or better on an intralaboratory basis. This level of analytical precision equates to a comparable level of precision (1-3‰) in the calculated age, depending on the extent of atmospheric Ar contamination, importance of nucleogenic interference corrections, and other factors. However, it has become clear that improving the precision of mass spectrometry is not the only bottleneck towards improving the accuracy and precision of 40Ar/39Ar dating in general. Rather, the most urgent issue is interlaboratory reproducibility. This became obvious in a recent EARTHTIME initiative undertaken to intercalibrate two commonly used 40Ar/39Ar standards [the Fish Canyon sanidine (FCs) and the Alder Creek sanidine (ACs)]. This effort revealed variations amongst laboratories (at the 1-2% level), an order of magnitude greater than the internal analytical precisions. To address these issues, we have proposed (to NSF) to construct two identical pipette systems loaded to identical starting pressures and with identical isotopic compositions. One pipette system will travel between participating 40Ar/39Ar labs and the second system will not travel and serve as the “Master” system to test for any fractionation or undocumented depletion of the traveling pipette system. In order to ensure delivery of uniform amounts of homogenous gas, the pipette system will be computer-controlled with preprogrammed routines and lockouts to prevent compromising the reservoirs. The pipette systems will deliver three gas samples with different isotopic ratios at two different pressures/concentrations. One pipette bulb will be of atmospheric isotopic composition, and the other two pipette bulbs will have 40Ar*/39ArK ratios corresponding to co-irradiated ACs and FCs fixed by their

  12. 46 CFR 98.25-65 - Filling density.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Filling density. 98.25-65 Section 98.25-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL... § 98.25-65 Filling density. (a) The filling density, or the percent ratio of the liquefied gas that...

  13. Simulations of the new cryogenic gas filled stopping cell for the low energy branch of the Super-FRS at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Reiter, Moritz Pascal; Schaefer, Daniel [Justus-Liebig-Universitaet Giessen (Germany); Dickel, Timo; Plass, Wolfgang; Geissel, Hans; Scheidenberger, Christoph [Justus-Liebig-Universitaet Giessen (Germany); GSI, Darmstadt (Germany); Collaboration: FRS Ion Catcher-Collaboration

    2012-07-01

    At the low energy branch of the Super-FRS at FAIR exotic nuclei will be produced at relativistic energies, slowed down, thermalized and provided as a low energy beam to high precision experiments. The ions are stopped in a cryogenic stopping cell in high density helium gas. In order to guide the development of the new cryogenic stopping cell and to study the performance of the new techniques used, numerical simulations of the stopping cell have been performed. A parameter study of the RF carpet has been done and optimized working parameters for the stopping cell have been found. The simulation results show good agreement with the first offline and online experiments of the cryogenic stopping cell obtained at the FRS Ion Catcher at GSI. For the first time cryogenic operation of a stopping cell with a radio frequency carpet and hitherto unreached helium densities have been demonstrated.

  14. The radon gas at the context of legislation on the quality of internal air in buildings - the Portuguese experience; O gas radao no contexto da legislacao sobre a qualidade do ar interior em edificios - a experiencia portuguesa

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Paulo G.A.N.; Pereira, Alcides J.S.C.; Neves, Luis J.P.F., E-mail: ppinto@dct.uc.p, E-mail: apereira@dct.uc.p, E-mail: luisneves@dct.uc.p [Universidade de Coimbra (Portugal). Dept. de Ciencias da Terra. Instituto do Mar

    2011-10-26

    Radon gas has been recognized as an important environmental risk factor, especially when found in high concentrations inside buildings, and is currently classified by the World Health Organization as a carcinogen type 1. In this context, there is legislation in Portugal since 2006 that sets limits to its concentration in indoor air. The aim of this work was to synthesize the existing legislation with focus on the sampling and analysis. Some statistical data about the measurements obtained in the Natural Radioactivity Laboratory, of the Department of Earth Sciences, of the University of Coimbra are presented, and discussed in the context of the National Energy Certification of Buildings System

  15. Subterranean production of neutrons, 39Ar and 21Ne: Rates and uncertainties

    Science.gov (United States)

    Šrámek, Ondřej; Stevens, Lauren; McDonough, William F.; Mukhopadhyay, Sujoy; Peterson, R. J.

    2017-01-01

    Accurate understanding of the subsurface production rate of the radionuclide 39Ar is necessary for argon dating techniques and noble gas geochemistry of the shallow and the deep Earth, and is also of interest to the WIMP dark matter experimental particle physics community. Our new calculations of subsurface production of neutrons, 21Ne , and 39Ar take advantage of the state-of-the-art reliable tools of nuclear physics to obtain reaction cross sections and spectra (TALYS) and to evaluate neutron propagation in rock (MCNP6). We discuss our method and results in relation to previous studies and show the relative importance of various neutron, 21Ne , and 39Ar nucleogenic production channels. Uncertainty in nuclear reaction cross sections, which is the major contributor to overall calculation uncertainty, is estimated from variability in existing experimental and library data. Depending on selected rock composition, on the order of 107-1010 α particles are produced in one kilogram of rock per year (order of 1-103 kg-1 s-1); the number of produced neutrons is lower by ∼ 6 orders of magnitude, 21Ne production rate drops by an additional factor of 15-20, and another one order of magnitude or more is dropped in production of 39Ar. Our calculation yields a nucleogenic 21Ne /4He production ratio of (4.6 ± 0.6) ×10-8 in Continental Crust and (4.2 ± 0.5) ×10-8 in Oceanic Crust and Depleted Mantle. Calculated 39Ar production rates span a great range from 29 ± 9 atoms kg-rock-1 yr-1 in the K-Th-U-enriched Upper Continental Crust to (2.6 ± 0.8) × 10-4 atoms kg-rock-1 yr-1 in Depleted Upper Mantle. Nucleogenic 39Ar production exceeds the cosmogenic production below ∼700 m depth and thus, affects radiometric ages of groundwater. The 39Ar chronometer, which fills in a gap between 3H and 14C , is particularly important given the need to tap deep reservoirs of ancient drinking water.

  16. A Participatory Geographic Information System (PGIS Utilizing the GeoWeb 2.0: Filling the Gaps of the Marcellus Shale Natural Gas Industry

    Directory of Open Access Journals (Sweden)

    Drew Michanowicz

    2012-06-01

    Full Text Available The application of neocartography, specifically through the Web 2.0, is a new phase of participatory geographic information system (PGIS research. Neocartography includes the encouragement of non-expert participation through visual design (e.g., map layering, and knowledge discovery via the Web. To better understand the challenges from an increase in natural gas extraction in the Marcellus Shale region of the United States, a GeoWeb 2.0 platform titled FracTracker (FracTracker.org that relies upon PGIS and neocartography was created and implemented in June 2010. FracTracker focuses on data-to-information translation to stimulate capacity building for a range of user types by leveraging the immense benefits of a spatial component. The main features of FracTracker are the ability to upload and download geospatial data as various file types, visualize data through thematic mapping and charting tools, and learn about and share drilling experiences. In less than 2 years, 2,440 registered users have effectively participated in creating 956 maps or „snapshots' using 399 available datasets. FracTracker demonstrates that participatory, interoperable GeoWebs can be utilized to help understand and localize related impacts of complex systems, such as the extractive energy industry.

  17. Ramon Llull's Ars Magna

    DEFF Research Database (Denmark)

    Jensen, Thessa

    of the Christian faith. He soon discovered that the main challenge was to explain the divine Trinity to non Christians. Furthermore, he realised that culture and language barriers must be taken into account when he tried to explain the Christian faith. In-stead of focussing on the differences, Llull sought out...... might be a viable and valuable approach to understand some of the challenges and possibilities found in computer science and ethics. Vita Llull was born in 1232 in Palma de Mallorca, a melting pot for different cul-tures and religions at the time. Being educated at the king’s court, Llull learned......Ramon Llull’s Ars Magna Thessa Jensen Institute for Communication and Psychology, Aalborg University Aalborg, Denmark thessa@hum.aau.dk The Great Art of Ramon Llull — the Ars Magna — must be seen as one of the basic philosophical approaches to formalisation of thought, language, and knowledge...

  18. Combined K-Ar and 40Ar/39Ar dating of the upper Jaramillo reversal

    Science.gov (United States)

    Guillou, Herve; Carracedo, Juan Carlos; Kissel, Catherine; Laj, Carlo; Nomade, Sebastien; Perez Torrado, Francisco Jose; Rodriguez Gonzalez, Alejandro; Wandres, Camille

    2013-04-01

    The Jaramillo subchron was first evidenced in 1966 (Doell and Dalrymple) through the Rhyolotic domes of the Valles Caldera, New Mexico (USA). 40Ar/39Ar studies achieved by Spell et McDougall (1992), Spell et Harrison (1993), Izett and Obradovich (1994) and Singer et al. (1994) defined the base of this subchron at 1053±6 ka, and the ceiling at 986±5 ka. Channell et al. (2009) delimited the age of the Jaramillo subchron by astronomic calibration (base 1071 ka, top 990 ka). To provide additional absolute ages on this geomagnetic period, which is critical to improve our knowledge of the earth magnetic field behaviour, we have carried out a study combining paleomagnetism and isotopic dating of a lava sequence from Tenerife island. This sequence of basaltic lava flows is some 500 m thick. The first 400 m present, based on field magnetometer measurements, normal polarity lavas, with dykes of normal and reverse polarity, passing at the top to reverse polarity lavas. Preliminary K-Ar ages bracketed this sequence between 1018 ± 18 ka and 978 ± 17 ka. Therefore, the upper Jaramillo reversal at least appeared to be potentially recorded in this sequence. A more detailed paleomagnetic study was then carried out to more precisely delimit the reversal itself (see Laj et al., session EMRP3.4). We have undertaken 40Ar/39Ar incremental heating and unspiked K-Ar experiments on groundmass from four transitionally magnetized flows. The first transitional flow is K-Ar dated at 993 ± 18 ka and 40Ar/39Ar dated at 991 ± 13 ka, the second at 981 ± 17 ka (K-Ar) and 1000 ± 13 ka (40Ar/39Ar), the third at 950 ± 17 ka (K-Ar) and 1000 ± 8 ka (40Ar/39Ar) and the fourth at 984 ± 17 ka (K-Ar) and 977 ± 12 (40Ar/39Ar). 40Ar/39Ar ages and K-Ar ages (relative to FCT 28.02 Ma) are indistinguishable at 2σ. The age of the upper boundary of the Jaramillo event calculated combining 40Ar/39Ar ages and K-Ar ages is 992 ± 6 ka, in agreement with previous estimates.

  19. Photoionization of Ar VIII

    Science.gov (United States)

    Liang, Liang; Jiang, Wen-xian; Zhou, Chao

    2017-01-01

    The photoionization cross section, energy levels and widths of 22 Rydberg series (in the autoionization region) for Na-like Ar VIII were investigated by using of R-matrix method. The relativistic distorted-wave method is used to calculate the radial functions, and QB method of Quigly-Berrington [Quigley et al. 1998] is employed to calculate the resonance levels and widths. We have identified the formant in the figure of the photoionization cross section.

  20. Ars Electronica tulekul / Rael Artel

    Index Scriptorium Estoniae

    Artel, Rael, 1980-

    2003-01-01

    6.-11. IX toimub Austrias Linzis "Ars Electronica" festival, mille teema on "Code - The Language of Our Time". Festivali kavast, osalejatest, ava-performance'ist "Europe - A Symphonic Vision", näitusest "Cyberarts 2003. Prix Ars Electronica"

  1. ARABIC LIGHT STEMMER (ARS

    Directory of Open Access Journals (Sweden)

    ASMA AL-OMARI

    2014-12-01

    Full Text Available Stemming is a main step used to process textual data. It is usually used in several types of applications such as: text mining, information retrieval (IR, and natural language processing (NLP. A major task in stemming is to standardize words; which can be achieved by reducing each word to its base (root or stem. Arabic stemming is not an easy task. Unlike other languages, Arabic language is a highly inflected language, since it uses many inflectional forms. Researchers are divided on the benefit of using stemming in fields of IR, NLP...etc., since in Arabic the morphological variants of a certain word are not always semantically related. The aim of this paper is to design and implement a new Arabic light stemmer (ARS which is not based on Arabic root patterns. Instead, it depends on well defined mathematical rules and several relations between letters. A series of tests were conducted on ARS stemmer to compare its effectiveness with the effectiveness of two other Arabic stemmers. Test shows clearly the effectiveness superiority of ARS compared to effectiveness of these two Arabic stemmers.

  2. Project of multiple controller models for the maintenance of air/fuel ratio in natural gas internal combustion motors; Projeto de controladores multiplos modelos para manutencao da relacao ar/combustivel em motores de combustao interna movidos a gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Freitas Junior, Fernando Sousa e; Fleury, Agenor de Toledo [Sao Paulo Univ. SP (Brazil). Escola Politecnica. Dept. de Engenharia Mecanica]. E-mails: ffreitas@usp.br; agfleury@ipt.br

    2006-07-01

    The objective of this work is the study of advanced control techniques for the reduction of pollutant gases generated by internal combustion engines powered by natural gas. In this paper three techniques are applied to control the fuel injection and the ignition timing: the Generalized Predictive Control (GPC), the Linear Quadratic Regulator (LQR) and H{infinity} Control by Linear Matrix Inequalities (LMI). To each one of those techniques were developed a multiple model structure seeking to include the vast operation region of the engine. The controller's performance is measured by the efficiency in maintaining the fuel/air ratio around 1% of maximum deviation in relation to the stoichiometric value. The results show the possibility of controlling pollutant emission generated by this kind of engine to conform to international emission standards, improving life quality. (author)

  3. Resonant proton scattering on 46Ar using the Active-Target Time Projection Chamber

    Science.gov (United States)

    Bradt, J.; Ahn, T.; Ayyad Limonge, Y.; Bazin, D.; Beceiro Novo, S.; Carpenter, L.; Kuchera, M. P.; Lynch, W.; Mittig, W.; Rost, S.; Watwood, N.; Barney, J.; Datta, U.; Estee, J.; Gillibert, A.; Manfredi, J.; Morfouace, P.; Perez Loureiro, D.; Pollacco, E.; Sammut, J.; Sweany, S.

    2016-09-01

    A well-known technique for studying the single-particle properties of neutron-rich nuclei is to use resonant proton scattering on a parent nucleus to populate the isobaric analog states of the corresponding neutron-rich nucleus. The locations and amplitudes of these resonances are directly related to the structure of the nucleus of interest by isospin symmetry. We performed an experiment of this type at the National Superconducting Cyclotron Laboratory to commission the recently completed Active-Target Time Projection Chamber (AT-TPC). A 4.6-MeV/u radioactive beam of 46Ar was injected into the AT-TPC. The detector was filled with isobutane gas-which provided the protons for the reaction and served as the tracking medium-and placed inside a 2-T magnetic field. We will present preliminary results from this experiment and discuss the benefits of the active-target method for this type of measurement.

  4. Primary retention following nuclear recoil in β-decay: Proposed synthesis of a metastable rare gas oxide ((38)ArO4) from ((38)ClO4(-)) and the evolution of chemical bonding over the nuclear transmutation reaction path.

    Science.gov (United States)

    Timm, Matthew J; Matta, Chérif F

    2014-12-01

    Argon tetroxide (ArO4) is the last member of the N=50 e(-) isoelectronic and isosteric series of ions: SiO4(4-), PO4(3-), SO4(2-), and ClO4(-). A high level computational study demonstrated that while ArO4 is kinetically stable it has a considerable positive enthalpy of formation (of ~298kcal/mol) (Lindh et al., 1999. J. Phys. Chem. A 103, pp. 8295-8302) confirming earlier predictions by Pyykkö (1990. Phys. Scr. 33, pp. 52-53). ArO4 can be expected to be difficult to synthesize by traditional chemistry due to its metastability and has not yet been synthesized at the time of writing. A computational investigation of the changes in the chemical bonding of chlorate (ClO4(-)) when the central chlorine atom undergoes a nuclear transmutation from the unstable artificial chlorine isotope (38)Cl to the stable rare argon isotope (38)Ar through β-decay, hence potentially leading to the formation of ArO4, is reported. A mathematical model is presented that allows for the prediction of yields following the recoil of a nucleus upon ejecting a β-electron. It is demonstrated that below a critical angle between the ejected β-electron and that of the accompanying antineutrino their respective linear momentums can cancel to such an extent as imparting a recoil to the daughter atom insufficient for breaking the Ar-O bond. As a result, a primary retention yield of ~1% of ArO4 is predicted following the nuclear disintegration. The study is conducted at the quadratic configuration interaction with single and double excitations [QCISD/6-311+G(3df)] level of theory followed by an analysis of the electron density by the quantum theory of atoms in molecules (QTAIM). Crossed potential energy surfaces (PES) were used to construct a PES from the metastable ArO4 ground singlet state to the Ar-O bond dissociation product ArO3+O((3)P) from which the predicted barrier to dissociation is ca. 22kcal/mol and the exothermic reaction energy is ca. 28kcal/mol [(U)MP2/6-311+G(d)].

  5. H- Beam Stripping Loss at Background Partial Pressure of Ar

    Institute of Scientific and Technical Information of China (English)

    Hu Chundong; Wang Shaohu; Hu Liqun

    2005-01-01

    It has been observed that H- current could be improved by adding Ar to H2 plasma.But due to a slower pumping speed for Ar with the existing pumping scheme, the tank pressure will increase quickly during the length of a beam pulse. Since H- stripping loss depends on the tank pressure and gas species, part of the H- beam can be converted to H0 and then H0 can be converted into H+ with background H2 and Ar gas thickness. Therefore, the H- beam current,measured by a Faraday cup, situated at a distance L from GG (ground grid), will decrease because it will be converted into a H+ current. This gives a ratio of the Faraday cup net current to the H- beam current before stripping at background partial pressure of Ar.

  6. Acoustic resonance spectroscopy (ARS): ARS300 operations manual, software version 2.01

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-25

    Acoustic Resonance Spectroscopy (ARS) is a nondestructive evaluation technology developed at the Los Alamos National Laboratory. The ARS technique is a fast, safe, and nonintrusive technique that is particularly useful when a large number of objects need to be tested. Any physical object, whether solid, hollow, or fluid filled, has many modes of vibration. These modes of vibration, commonly referred to as the natural resonant modes or resonant frequencies, are determined by the object`s shape, size, and physical properties, such as elastic moduli, speed of sound, and density. If the object is mechanically excited at frequencies corresponding to its characteristic natural vibrational modes, a resonance effect can be observed when small excitation energies produce large amplitude vibrations in the object. At other excitation frequencies, i.e., vibrational response of the object is minimal.

  7. Simulating thermo-mechanical interaction between a xenon gas-filled chamber and tungsten first-wall armor for the LIFE reactor design using the BUCKY 1-D radiation hydrodynamics code

    Energy Technology Data Exchange (ETDEWEB)

    Heltemes, T A; Prochaska, A E; Moses, G A, E-mail: taheltemes@wisc.ed [Fusion Technology Institute, University of Wisconsin - Madison, 1500 Engineering Dr., Madison WI 53706 (United States)

    2010-08-01

    The BUCKY 1-D radiation hydrodynamics code has been used to simulate the dynamic thermo-mechanical interaction between a xenon gas-filled chamber and tungsten first-wall armor with an indirect-drive laser fusion target for the LIFE reactor design. Two classes of simulations were performed: (1) short-time (0-2 ms) simulations to fully capture the hydrodynamic effects of the introduction of the LIFE indirect-drive target x-ray and ion threat spectra and (2) long-time (2-70 ms) simulations starting with quiescent chamber conditions characteristic of those at 2 ms to estimate xenon plasma cooling between target implosions at 13 Hz. The short-time simulation results reported are: (1) the plasma hydrodynamics of the xenon in the chamber, (2) dynamic overpressure on the tungsten armor, and (3) time-dependent temperatures in the tungsten armor. The ramifications of local thermodynamic equilibrium (LTE) vs. non-LTE opacity models are also addressed.

  8. New numerical algorithm of gas-liquid two-phase flow considering characteristics of liquid metal during mold filling%基于充型过程金属液流动特点的气-液两相流算法模型

    Institute of Scientific and Technical Information of China (English)

    牛晓峰; 方钊; 梁伟; 侯华; 王红霞

    2014-01-01

    A new program is developed for gas-liquid two-phase mold filling simulation in casting. The gas fluid, the superheated liquid metal and the liquid metal containing solid grains are assumed to be governed by Navier-Stokes equations and solved through Projection method. The Level set method is used to track the gas-liquid interface boundary. In order to demonstrate the correctness of this new program for simulation of gas-liquid two-phase mold filling in casting, a benchmark filling experiment is simulated (this benchmark test is designed by XU and the filling process is recorded by a 16-mm film camera). The simulated results agree very well with the experimental results, showing that this new program can be used to properly predicate the gas-liquid two-phase mold filling simulation in casting.%针对在铸件充型过程中,金属液表现出不同的流动特点,含有固体颗粒的金属液具有不可压缩非牛顿流的流动特性,而过热金属液具有不可压缩牛顿流的流动特点,采用 Projection 方法求解气体、过热金属液和含有固体颗粒的金属液的速度场,用Level set方法来追踪气-液界面边界。为了验证计算模型,将模拟结果与实验结果(采用16 mm摄像机记录充型过程)进行比对,从而证明计算模型的正确性。

  9. Phase-matched high-order harmonics by interaction of Ar atoms with high-repetition-rate low-energy femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    XIE Xinhua; ZENG Zhinan; LI Ruxin; CHEN Shu; LU Haihe; YIN Dingjun; XU Zhizhan

    2004-01-01

    Phase-matched high-order harmonic generation in Ar gas-filled cell was investigated experimentally. We obtained phase-matched 27th order harmonic driven by a commercially available solid-state femtosecond laser system at 0.55 m J/pulse energy level and 1 kHz repetition rate. To our knowledge, this is the lowest driving laser energy used to obtain phase-matched 27th order harmonic in a static gas cell. High-order harmonic generation at different gas density was studied systematically. Spectral blueshift and broadening of high harmonics under different pressure were analyzed. We found that the source size and spatial distribution of high-order harmonics are quite different under the phase-matching condition from those of the phase-mismatching case.

  10. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  11. Late Paleozoic deformation and exhumation in the Sierras Pampeanas (Argentina): 40Ar/39Ar-feldspar dating constraints

    Science.gov (United States)

    Löbens, Stefan; Oriolo, Sebastián; Benowitz, Jeff; Wemmer, Klaus; Layer, Paul; Siegesmund, Siegfried

    2016-09-01

    Systematic 40Ar/39Ar feldspar data obtained from the Sierras Pampeanas are presented, filling the gap between available high- (>~300 °C) and low-temperature (Pie de Palo regions, whereas the Sierras de San Luis and the Sierra de Comechingones regions record exhumation during the Carboniferous. Comparison between new and available data points to a Carboniferous tectonic event in the Sierras Pampeanas, which represents a key period to constrain the early evolution of the proto-Andean margin of Gondwana. This event was probably transtensional and played a major role during the evolution of the Paganzo Basin as well as during the emplacement of alkaline magmatism in the retroarc.

  12. 40Ar/39Ar Interlaboratory Calibration into the Holocene.

    Science.gov (United States)

    Heizler, M. T.; Jicha, B.; Koppers, A. A. P.; Miggins, D. P.

    2015-12-01

    Advances in 40Ar/39Ar analytical precision for very young rocks requires collaborative efforts amongst argon geochronology labs to demonstrate age reproducibility commensurate with high precision. NM Tech (NMT), the University of Wisconsin (UW) and Oregon State University (OSU) have each dated Quaternary flux monitor standard AC-2 sanidine (~1.185 Ma), a blind sanidine described as being 50-100 ka (BS) and sanidine from the Qixiangshan (QIX) flow (~10 ka), Changbaishan volcano, China. The samples were irradiated in a single package with FC-2 sanidine (28.201 Ma) as the flux monitor and the irradiated material was distributed amongst the labs. Heizler was present during analysis at both OSU and UW and Jicha attended OSU during analysis. Physical presence was key towards gaining understanding of individual protocols and prompted valuable discussions. Analyses were carried out on single crystals using total fusion and/or step heating approaches. Age agreement was achieved within 2s uncertainty that ranged between (0.03-0.3%, 0.13-0.37% and 1.8-2.6%) for AC-2, BS and QIX, respectively. Each lab found AC-2 to vary somewhat beyond a normal distribution and to yield an age relative to FC-2 of ~1.185 Ma that is ~1.3% (~5-10 sigma) lower than some published estimates. A key cause of the variation between this study and previous results may be variable gas pressure equilibration times between extraction line and mass spectrometer coupled with variable choices to estimate time zero by other laboratories. The majority of our efforts concentrated on the QIX sanidine where prior data obtained by our labs revealed a factor of two spread in age (~11 and 23 ka) based on experiments carried out by total fusion and bulk incremental heating. By conducting single crystal age spectrum analysis we were able to mitigate effects of melt inclusion hosted excess argon and xenocrystic contamination towards obtaining analytical agreement with apparent ages near 10 ka. However, philosophical

  13. 40Ar/39Ar age calibration against counted annuallayers

    DEFF Research Database (Denmark)

    Storey, Michael; Stecher, Ole

    2008-01-01

    worth exploring for an improved absolute age basis for the 40Ar/39Ar system is through cross-calibration with counted annual layers (e.g. tree rings, varves and ice cores). North Atlantic Ash Zone (NAAZ) II is found within the dated part of the annual Greenland ice core record. NAAZ II has been...

  14. Computational phase diagrams of noble gas hydrates under pressure.

    Science.gov (United States)

    Teeratchanan, Pattanasak; Hermann, Andreas

    2015-10-21

    We present results from a first-principles study on the stability of noble gas-water compounds in the pressure range 0-100 kbar. Filled-ice structures based on the host water networks ice-Ih, ice-Ic, ice-II, and C0 interacting with guest species He, Ne, and Ar are investigated, using density functional theory (DFT) with four different exchange-correlation functionals that include dispersion effects to various degrees: the non-local density-based optPBE-van der Waals (vdW) and rPW86-vdW2 functionals, the semi-empirical D2 atom pair correction, and the semi-local PBE functional. In the He-water system, the sequence of stable phases closely matches that seen in the hydrogen hydrates, a guest species of comparable size. In the Ne-water system, we predict a novel hydrate structure based on the C0 water network to be stable or at least competitive at relatively low pressure. In the Ar-water system, as expected, no filled-ice phases are stable; however, a partially occupied Ar-C0 hydrate structure is metastable with respect to the constituents. The ability of the different DFT functionals to describe the weak host-guest interactions is analysed and compared to coupled cluster results on gas phase systems.

  15. High-Energy Ions Emitted from Ar Clusters Irradiated by Intense Femtosecond Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    LI Zhong; LEI An-Le; NI Guo-Quan; XU Zhi-Zhan

    2000-01-01

    We have experimentally studied the energy spectra of Ar ions emitted from Ar clusters irradiated by intense femtosecond laser pulses. The Ar clusters were produced in the adiabatic expansion of Ar gas into vacuum at high backing pressures. The laser peak intensity was about 2×106 W/cm2 with a pulse duration of 45 fs. The maximum and the average energies of Ar ions are 0.2 MeV and 15kev at a backing pressure of 2. S MPa, respectively. They are almost independent of the backing pressures in the range of 0.6 to 4.5 MPa.

  16. Stationary afterglow measurements of the temperature dependence of the electron–ion recombination rate coefficients of {{\\rm{H}}}_{2}{{\\rm{D}}}^{+} and {{HD}}_{2}^{+} in He/Ar/H2/D2 gas mixtures at T = 80–145 K 

    Science.gov (United States)

    Plašil, Radek; Dohnal, Petr; Kálosi, Ábel; Roučka, Štěpán; Johnsen, Rainer; Glosík, Juraj

    2017-03-01

    We report measurements of the binary and ternary recombination rate coefficients of deuterated isotopologues of {{{H}}}3+. A cavity ring-down absorption spectrometer was used to monitor the fractional abundances of {{{H}}}3+, {{{H}}}2{{{D}}}+, {{HD}}2+ and {{{D}}}3+ during the decay of a plasma in He/Ar/{{{H}}}2/{{{D}}}2 mixtures. A dependence of the measured effective recombination rate coefficients on the helium buffer gas density was observed and hence both the binary and the ternary recombination rate coefficients for {{{H}}}2{{{D}}}+ and {{HD}}2+ were obtained in the temperature range 80–145 K.

  17. Research on Technology of Filling Sodium into Fuel Test Capsules

    Institute of Scientific and Technical Information of China (English)

    XU; Chi; XIE; Chun; WANG; Shu-xing; MI; Zheng-feng; YU; Tuan-jie; CUI; Chao; WANG; Ming-zheng

    2015-01-01

    In order to provide a high pure sodium environment for properties testing in the fuel research for fast reactor,it is essential to fill sodium into fuel testing capsules.By the method of vacuum,temperature-controlling and inert gas protection,quantificational sodium had been filled into the fuel testing capsules.Fig.1shows the schematic diagram of sodium filling device.Table 1shows

  18. 40Ar/39Ar and U-Th-Pb dating of separated clasts from the Abee E4 chondrite

    Science.gov (United States)

    Bogard, D.D.; Unruh, D.M.; Tatsumoto, M.

    1983-01-01

    Determinations of 40Ar/39Ar and U-Th-Pb are reported for three clasts from the Abee (E4) enstatite chondrite, which has been the object of extensive consortium investigations. The clasts give 40Ar/39Ar plateau ages and/or maximum ages of 4.5 Gy, whereas two of the clasts give average ages of 4.4 Gy. Within the range of 4.4-4.5 Gy these data do not resolve any possible age differences among the three clasts. 206Pb measured in these clasts is only ???1.5-2.5% radiogenic, which leads to relatively large uncertainties in the Pb isochron age and in the 207Pb/206Pb model ages. The Pb data indicate that the initial 207Pb/206Pb was no more than 0.08??0.07% higher than this ratio in Can??on Diablo troilite. The U-Th-Pb data are consistent with the interpretation that initial formation of these clasts occurred 4.58 Gy ago and that the clasts have since remained closed systems, but are contaminated with terrestrial Pb. The 40Ar/39Ar ages could be gas retention ages after clast formation or impact degassing ages. The thermal history of Abee deduced from Ar data appears consistent with that deduced from magnetic data, and suggests that various Abee components experienced separate histories until brecciation no later than 4.4 Gy ago, and experienced no appreciable subsequent heating. ?? 1983.

  19. Neutron-hole states in 45Ar from p(46Ar,d)45Ar reactions

    CERN Document Server

    Lu, F; Tsang, M B; Bazin, D; Coupland, D; Henzl, V; Henzlova, D; Kilburn, M; Lynch, W G; Rogers, A M; Sanetullaev, A; Sun, Z Y; Youngs, M; Charity, R J; Sobotka, L G; Famiano, M; Hudan, S; Horoi, M; Ye, Y L

    2013-01-01

    To improve the effective interactions in the pf shell, it is important to measure the single particle- and hole- states near the N=28 shell gap. In this paper, the neutron spectroscopic factors of hole-states from the unstable neutron-rich 45Ar (Z=18, N=27) nucleus have been studied using 1H(46Ar, 2H)45Ar transfer reaction in inverse kinematics. Comparison of our results with the particle-states of 45Ar produced in 2H(44Ar, H)45Ar reaction shows that the two reactions populate states with different angular momentum. Using the angular distributions, we are able to confirm the spin assignments of four low-lying states of 45Ar. These are the ground state (f7/2), the first-excited (p3/2), the s1/2 and the d3/2 states. While large basis shell model predictions describe spectroscopic properties of the ground and p3/2 states very well, they fail to describe the s1/2 and d3/2 hole-states.

  20. Ars Poetica : [luuletused] / Mats Traat

    Index Scriptorium Estoniae

    Traat, Mats, 1936-

    2008-01-01

    Sisu: Ars poetica ; Veepeegel ; Kontrollõed ; Mandariiniriik ; Nikolai Siamashvili (1888-1911) ; Kolmekümne kolmas aasta ; Kiri linast 1966 ; Italmaz Nuriyev ; Rudolf Rimmelile mõeldes ; Gennadi Aigi

  1. Natural ³⁷Ar concentrations in soil air: implications for monitoring underground nuclear explosions.

    Science.gov (United States)

    Riedmann, Robin A; Purtschert, Roland

    2011-10-15

    For on-site inspections (OSI) under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) measurement of the noble gas ³⁷Ar is considered an important technique. ³⁷Ar is produced underground by neutron activation of Calcium by the reaction ⁴⁰Ca(n,α)³⁷Ar. The naturally occurring equilibrium ³⁷Ar concentration balance in soil air is a function of an exponentially decreasing production rate from cosmic ray neutrons with increasing soil depth, diffusive transport in the soil air, and radioactive decay (T(1/2): 35 days). In this paper for the first time, measurements of natural ³⁷Ar activities in soil air are presented. The highest activities of ~100 mBq m⁻³ air are 2 orders of magnitude larger than in the atmosphere and are found in 1.5-2.5 m depth. At depths > 8 m ³⁷Ar activities are < 20 mBq m⁻³ air. After identifying the main ³⁷Ar production and gas transport factors the expected global activity range distribution of ³⁷Ar in shallow subsoil (0.7 m below the surface) was estimated. In high altitude soils, with large amounts of Calcium and with low gas permeability, ³⁷Ar activities may reach values up to 1 Bq m⁻³.

  2. The structure, properties, and nature of HArF-benzene complex: redshift and blueshift of Ar-H stretch frequency and rare gas atomic number dependence of hydrogen bonds.

    Science.gov (United States)

    Liu, Xiaofeng; Li, Qingzhong; Li, Ran; Li, Wenzuo; Cheng, Jianbo

    2011-12-15

    Ab initio calculations have been performed for the complexes of benzene with HArF, HKrF, and HXeF. The computed results indicate that the complexes of benzene-HArF exist in different conformations and among them those with π-hydrogen bonds are the more stable than those with C-H···F hydrogen bonds. Interestingly, the Ar-H stretching frequency is redshifted in the more stable isomer and blueshifted in the less stable form. The Ng (Ng=Ar, Kr, and Xe) atomic number dependence of the Ng-H···π and C-H···F hydrogen bonds has been explored. The result indicates that the strength of Ng-H···π and C-H···F hydrogen bonds is weakened with the increase of Ng atomic number. Natural bond orbital analysis has been performed to understand the interaction nature, frequency shift of H-Ng stretch, and dependence of Ng-H···π and C-H···F hydrogen bonds on the Ng atomic number.

  3. The effect of tube filling on the electronic properties of Fe filled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Linganiso, Ella C. [Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050 (South Africa); Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Johannesburg 2050 (South Africa); Chimowa, George [Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Johannesburg 2050 (South Africa); Franklyn, Paul J. [Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050 (South Africa); Bhattacharyya, Somnath [Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Johannesburg 2050 (South Africa); Coville, Neil J., E-mail: neil.coville@wits.ac.za [Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050 (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Johannesburg 2050 (South Africa)

    2012-02-15

    Graphical abstract: HRTEM image of a twisted CNT filled with a bent single crystal of Fe. Insets from top to bottom show the power spectra of the corresponding regions, indicating the twisting of the Fe lattice. Inset in the top right shows the relative angling of the lattice fringes to accommodate the twisting of the Fe. Highlights: Black-Right-Pointing-Pointer Synthesis of Fe filled CNTs with Fe content varying from 3 to 35%. Black-Right-Pointing-Pointer TEM analysis indicates that Fe in the tubes is in contact with the CNTs. Black-Right-Pointing-Pointer TEM analysis reveals that {alpha}-Fe crystallizes after CNT formation. Black-Right-Pointing-Pointer Temperature dependent electronic transport measurements performed. Black-Right-Pointing-Pointer Conductivity varies with the % Fe filling in the CNTs. - Abstract: Carbon nanotubes filled with Fe nanostructures (Fe-CNTs) were synthesized using an injection method in a 1-stage horizontal CVD furnace and a bubbling method in a 2-stage horizontal CVD reactor. Fe-CNTs were obtained through the pyrolysis of a mixture of dichlorobenzene and ferrocene in 5%H{sub 2}/Ar. Metal impurities from the Fe-CNTs were removed using 1 M HCl solution. CNTs filled with crystalline Fe nanoparticles, nanorods and nanowires were obtained using these procedures. An intimate interaction between the Fe and the CNT was established by HRTEM studies. The {alpha}-Fe phase was observed to be the most dominant fraction found in the synthesized Fe-CNTs. The Fe{sub 2}O{sub 3} residue obtained from the TGA analysis revealed the amount of Fe filled inside the CNTs and this ranged between 3 and 31% by mass after purification. The temperature dependence of the conductivity in the temperature range between 2.5 and 100 K for an entangled network of Fe-CNTs was measured. An increase in conductivity due to the increased Fe filling inside the CNTs with increased temperature was observed. The observed temperature dependence was explained in terms of variable

  4. Adsorption of Ar on a nonuniform MgO surface

    Science.gov (United States)

    Hinman, D. C.; Halsey, G. D.

    1976-01-01

    Data are presented for the adsorption of Ar and N2 on a strongly heterogeneous MgO surface at 84 K and for Ar at a range of temperatures between 130 and 250 K. The high-temperature data are analyzed according to a model which separates the contributions to the potential into bulk and surface terms, providing a method for the determination of the surface area from parameters characteristic of the bulk material. A solid-gas energy parameter and parameters indicating the strength of the impurity sites are also evaluated.

  5. Low-Temperature DC Carrier Transport in (Fe0.45Co0.45Zr0.10x(Al2O31−x Nanocomposites Manufactured by Sputtering in Pure Ar Gas Atmosphere

    Directory of Open Access Journals (Sweden)

    Ivan A. Svito

    2015-01-01

    Full Text Available This presented work investigates the structure and temperature relationship/dependence of the DC conductivity σ(T in the (Fe0.45Co0.45Zr0.10x(Al2O31−x nanocomposites deposited in Ar atmosphere with composition (30

  6. Analysis list: Ar [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Ar Gonad,Kidney,Prostate + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/targe...t/Ar.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Ar.5.tsv http://dbarchive.biosciencedbc.jp/...kyushu-u/mm9/target/Ar.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Ar.Gonad.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/mm9/colo/Ar.Kidney.tsv,http://dbarchive.bioscienced...bc.jp/kyushu-u/mm9/colo/Ar.Prostate.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Gonad.gml,http://dbarchive.bioscience

  7. Neon reduction program on Cymer ArF light sources

    Science.gov (United States)

    Kanawade, Dinesh; Roman, Yzzer; Cacouris, Ted; Thornes, Josh; O'Brien, Kevin

    2016-03-01

    In response to significant neon supply constraints, Cymer has responded with a multi-part plan to support its customers. Cymer's primary objective is to ensure that reliable system performance is maintained while minimizing gas consumption. Gas algorithms were optimized to ensure stable performance across all operating conditions. The Cymer neon support plan contains four elements: 1. Gas reduction program to reduce neon by >50% while maintaining existing performance levels and availability; 2. short-term containment solutions for immediate relief. 3. qualification of additional gas suppliers; and 4. long-term recycling/reclaim opportunity. The Cymer neon reduction program has shown excellent results as demonstrated through the comparison on standard gas use versus the new >50% reduced neon performance for ArF immersion light sources. Testing included stressful conditions such as repetition rate, duty cycle and energy target changes. No performance degradation has been observed over typical gas lives.

  8. 40Ar/39Ar dating of Daqingshan thrust

    Institute of Scientific and Technical Information of China (English)

    LIU Zhenghong; XU Zhongyuan; YANG Zhensheng

    2003-01-01

    The Daqingshan thrust system, to the south of the Shiguai Mesozoic basin, is a complex system of top-to- the-north thrusting tectonic sheets. The thrust system has a complicated evolution due to multi-stage thrusting. In order to date the thrusting events, syntectonic muscovite and biotite grains are respectively analyzed with normal 40Ar/39Ar dating and laser 40Ar/39Ar dating, which yield 2 isochron ages, i.e. 193.74 ± 3.88 Ma and 121.6 ± 1.6 Ma. These ages suggest that faults within the Daqingshan thrust system formed during 2 stages of thrusting, one the early Indosinian and the other the late Yanshanian. The isotopic dating is consistent with field geological relations. Indosinan deformation is evidenced by top-to-the-north thrusting, with the occurrence of a series of large-scale east-west trending thrust faults and folds, while the Yanshanian thrusting is characterized by top-to-the-NNW thrusting. It is superposed on and modifies early Indosinian thrust faults.

  9. Laser fusion 40Ar/39Ar dating on young volcanic rocks.%(极)年轻火山岩激光熔蚀40Ar/39Ar定年

    Institute of Scientific and Technical Information of China (English)

    周晶; 季建清; Alan DEINO; 龚俊峰; 韩宝福; 涂继耀; 桑海清; 徐剑光

    2013-01-01

    It is extremely difficult to date young volcanic rocks.Accurate 40Ar/39Ar dating research and practice of young volcanic rocks in China put forward several notable and important points during the process of 40Ar/39 Ar dating for young volcanic rocks.Because of the low background level,small sample quantity,and high sensitivity of modem noble gas isotope mass spectrometry device,laser ablation 40Ar/39Ar dating technique has been used in depth application in volcanic rocks dating.With the laser in 40Ar/39Ar dating of young and modern volcanic rocks,the discrepancy of Nier value and initial argon isotope ratio in Quaternary samples may cause a remarkable deviation between K-Ar apparent age and 40 Ar/39 Ar apparent age.The deviation show exponential increase for samples younger than 0.2Ma,but it is not so notable for samples older than 2Ma.There out,the boundary of young and modern volcanic rocks,which is applied to 40 Ar/39 Ar system,is assigned at 0.2Ma:rocks aged 2 ~ 0.2Ma is defined as young volcanic rock,while rocks aged younger than 0.2Ma is defined as modem volcanic rock.The phenocrysts,which are from different argon isotope fractionation system,should be rejected from the sample during 40Ar/39 Ar dating.According to rock texture and grain size of mineral,the matrix should be picked with ideal grain size.In normal cases,about 0.2mm (or 60 ~ 80 mesh) is recommended; Cooling time after irradiation of fast neutron reactor should not be no more than three months,or else it may cause an error on 37 Ar measurement,and consequently on final results.As neutron-flux monitor,standards should be characteristic of high homogeneity during laser 40Ar/39Ar dating.In calibrating the international and domestic standards we have,we find that SB-778-Bi,Bern4M and BT-1 can be ideal standard samples with good homogeneity.We also find that the isochron age calculated from the laser 40Ar/39Ar data of the phenocryst and matrix,which were cooled and crystallized at the same time

  10. Variable leak gas source

    Science.gov (United States)

    Henderson, Timothy M.; Wuttke, Gilbert H.

    1977-01-01

    A variable leak gas source and a method for obtaining the same which includes filling a quantity of hollow glass micro-spheres with a gas, storing said quantity in a confined chamber having a controllable outlet, heating said chamber above room temperature, and controlling the temperature of said chamber to control the quantity of gas passing out of said controllable outlet. Individual gas filled spheres may be utilized for calibration purposes by breaking a sphere having a known quantity of a known gas to calibrate a gas detection apparatus.

  11. Preparing for faster filling

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Following the programmed technical stop last week, operators focussed on preparing the machine for faster filling, which includes multibunch injection and a faster pre-cycle phase.   The LHC1 screen shot during the first multibunch injection operation. The LHC operational schedule incorporates a technical stop for preventive maintenance roughly every six weeks of stable operation, during which several interventions on the various machines are carried out. Last week these included the replacement of a faulty magnet in the SPS pre-accelerator, which required the subsequent re-setting of the system of particle extraction and transfer to the LHC. At the end of last week, all the machines were handed back for operation and work could start on accommodating all the changes made into the complex systems in order for normal operation to be resumed. These ‘recovery’ operations continued through the weekend and into this week. At the beginning of this week, operators succeeded in pro...

  12. Bulk-Fill Resin Composites

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Havndrup-Pedersen, Cæcilie; Honoré, Daniel;

    2015-01-01

    the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization...... for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low......-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk...

  13. The study of properties of CdTe thin films deposited in Ar/O{{2}} atmosphere

    Science.gov (United States)

    Li, Y.; Li, B.; Feng, L.; Zheng, J.; Li, W.

    2009-02-01

    The preparation and properties of CdTe thin films is of a primary interest for the CdTe thin film solar cells in both research and technology. In our work, polycrystalline CdTe thin films were deposited on pretreated glass substrates in Ar/O{2} atmosphere by closed-space sublimation (CSS) technology. Structural property was studied by X-ray diffraction (XRD), surface morphology was observed by scanning electron microscopy (SEM). The optical and electrical properties of CdTe films were investigated, as well as the effects of deposition temperatures, the ratio of gas (Ar/O{2}) and post-treatment on the properties. The high quality CdTe layer was prepared based on the above studies. These layers were used to prepared CdS/CdTe/ZnTe:Cu solar cells. Efficiency of 13.38% and fill factor of 70.3% (0.501 cm2 area) for CdTe solar cells have been achieved. Project supported by the National High Technology Research and Development Program of China (Grant No.2003AA513010) and the National Natural Science Foundation of China (Grant No.60506004).

  14. AR DOC: Augmented reality documentaries

    DEFF Research Database (Denmark)

    Vistisen, Peter

    2014-01-01

    Augmented Reality Documentaries (AR DOC) er et ’lille’ Shareplay projekt (ansøgte midler augmented reality cross media løsninger, til at skabe engagerende publikumsformidling...... indenfor oplevelsesindustrien. Projektet har genereret ny viden omkring, hvordan fysisk og digital formidling kan understøttes via Augmented Reality som formidlingsformat....

  15. "Ars Electronica 2009" / Raivo Kelomees

    Index Scriptorium Estoniae

    Kelomees, Raivo, 1960-

    2009-01-01

    30. "Ars Electronica" festival "Human Nature" ("Inimese loomus") Linzis. Osaka ülikooli professori Hiroshi Ishiguro mehaanilis-digitaalsest nukust. Hübriidkunsti kategoorias peapreemia saanud Eduardo Kaci inimtaimest. Konverentsidest. Näitusest "See this Sound", mis oli pühendatud helile kujutavas kunstis

  16. Foreign gas broadening and shift of the strongly ``forbidden'' lead line at 1278.9nm

    Science.gov (United States)

    Horvatic, Vlasta; Veza, Damir; Movre, Mladen; Niemax, Kay; Vadla, Cedomil

    2008-06-01

    The collisional broadening and shift rate coefficients of the "forbidden" 6p 2 3P 0 → 6p 2 3P 1 transition in lead were determined by diode laser absorption measurements performed simultaneously in two resistively heated hot-pipes. One hot-pipe contained Pb vapor and noble gas (Ar or He) at low pressure, while the other was filled with Pb and noble gas at variable pressure. The measurements were performed at temperatures of 1220 K and 1290 K, i.e., lead number densities of 4.8 × 10 15 cm - 3 and 1.2 × 10 16 cm - 3 . The broadening rates were obtained by fitting the experimental collisionally broadened absorption line shapes to theoretical Voigt profiles. The shift rates were determined by measuring the difference between the peak absorption positions in the spectra measured simultaneously in the heat pipe filled with noble gas at reference pressure and the one with noble gas at variable pressure. The following data for the broadening and shift rate coefficients due to collisions with Ar and He were obtained: γBAr = (3.4 ± 0.1) × 10 - 10 cm 3 s - 1 , γBHe = (3.8 ± 0.1) × 10 - 10 cm 3 s - 1 , γSAr = (- 7.3 ± 0.8) × 10 - 11 cm 3 s - 1 , γSHe = (- 6.5 ± 0.7) × 10 - 11 cm 3 s - 1 .

  17. Optical Emission Spectroscopic Studies of ICP Ar Plasma

    Institute of Scientific and Technical Information of China (English)

    QI Xuelian; REN Chunsheng; ZHANG Jian; MA Tengcai

    2007-01-01

    The ion line of 434.8 nm and atom line of 419.8 nm of Ar plasma produced by an inductively coupled plasma (ICP) were measured by optical emission spectroscopy and the influences from the working gas pressure, radio-frequency (RF) power and different positions in the discharge chamber on the line intensities were investigated in this study. It was found that the intensity of Ar atom line increased firstly and then saturated with the increase of the pressure. The line intensity of Ar+, on the other hand, reached a maximum value and then decreased along with the pressure. The intensity of the line in an RF discharge also demonstrated a jumping mode and a hysteresis phenomenon with the RF power. When the RF power increased to 400 W, the discharge jumped from the E-mode to the H-mode where the line intensity of Ar atom demonstrated a sudden increase, while the intensity of Ar+ ion only changed slightly. If the RF power decreased from a high value, e.g., 1000 W, the discharge would jump from the H-mode back to the E-mode at a power of 300 W. At this time the intensities of Ar and Ar+ lines would also decrease sharply. It was also noticed in this paper that the intensity of the ion line depended on the detective location in the chamber, namely at the bottom of the chamber the line was more intense than that in the middle of the chamber, but less intense than at the top, which is considered to be related to the capacitance coupling ability of the ICP plasma in different discharge areas.

  18. High quality boron-doped epitaxial layers grown at 200°C from SiF4/H2/Ar gas mixtures for emitter formation in crystalline silicon solar cells

    Directory of Open Access Journals (Sweden)

    Ronan Léal

    2017-02-01

    Full Text Available Controlling the doping profile in solar cells emitter and front/back surface field is mandatory to reach high efficiencies. In the current state of the art, these doped layers are made by dopant diffusion at around 900°C, which implies potential temperature induced damages in the c-Si absorber and for which a precise control of doping is difficult. An alternative solution based on boron-doped epitaxial silicon layers grown by plasma-enhanced chemical vapor deposition (PECVD from 200°C using SiF4/H2/Ar/B2H6 chemistry is reported. The structural properties of the doped and undoped epitaxial layers were assessed by spectroscopic ellipsometry (SE, high resolution transmission electron microscopy (HR-TEM and X-ray diffraction (XRD. The incorporation of boron has been studied via plasma profiling time of flight mass spectrometry (PP-TOFMS and secondary ion mass spectrometry (SIMS measurements. The boron-doped epitaxial layers revealed excellent structural and electrical properties even for high carrier concentrations (>1019cm-3. Sheet resistances between 100 and 130 Ω/sq can been obtained depending on the thickness and the doping concentration, which is within the range of targeted values for emitters in c-Si solar cells. Electrochemical capacitance voltage (ECV revealed a uniform doping profile around 3.1019 cm-3 and by comparing with SIMS measurement a doping efficiency around 50% has been found.

  19. High quality boron-doped epitaxial layers grown at 200°C from SiF4/H2/Ar gas mixtures for emitter formation in crystalline silicon solar cells

    Science.gov (United States)

    Léal, Ronan; Haddad, Farah; Poulain, Gilles; Maurice, Jean-Luc; Roca i Cabarrocas, Pere

    2017-02-01

    Controlling the doping profile in solar cells emitter and front/back surface field is mandatory to reach high efficiencies. In the current state of the art, these doped layers are made by dopant diffusion at around 900°C, which implies potential temperature induced damages in the c-Si absorber and for which a precise control of doping is difficult. An alternative solution based on boron-doped epitaxial silicon layers grown by plasma-enhanced chemical vapor deposition (PECVD) from 200°C using SiF4/H2/Ar/B2H6 chemistry is reported. The structural properties of the doped and undoped epitaxial layers were assessed by spectroscopic ellipsometry (SE), high resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD). The incorporation of boron has been studied via plasma profiling time of flight mass spectrometry (PP-TOFMS) and secondary ion mass spectrometry (SIMS) measurements. The boron-doped epitaxial layers revealed excellent structural and electrical properties even for high carrier concentrations (>1019cm-3). Sheet resistances between 100 and 130 Ω/sq can been obtained depending on the thickness and the doping concentration, which is within the range of targeted values for emitters in c-Si solar cells. Electrochemical capacitance voltage (ECV) revealed a uniform doping profile around 3.1019 cm-3 and by comparing with SIMS measurement a doping efficiency around 50% has been found.

  20. Armenian Astronomical Society (ArAS) activities

    Science.gov (United States)

    Mickaelian, A. M.

    2016-09-01

    A review on the activities and achievements of Armenian Astronomical Society (ArAS) and Armenian astronomy in general during the last years is given. ArAS membership, ArAS electronic newsletters (ArASNews), ArAS webpage, Annual Meetings, Annual Prize for Young Astronomers (Yervant Terzian Prize) and other awards, international relations, presence in international organizations, local and international summer schools, science camps, astronomical Olympiads and other events, matters related to astronomical education, astronomical heritage, amateur astronomy, astronomy outreach and ArAS further projects are described and discussed.

  1. Method for filling a reactor with a catalyst

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for filling a reactor with a catalyst for the carbonylation of carbonylated compounds in the gas phase. According to said method, a SILP catalyst is covered with a filling agent which is liquid under normal conditions and is volatile under carbonylation reaction...... conditions, and a thus-treated catalyst is introduced into the reactor and the reactor is sealed....

  2. Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

    Science.gov (United States)

    Wilson, D. C.; Cassata, W. B.; Sepke, S. M.; Velsko, C. A.; Huang, H.; Yeamans, C. B.; Kline, J. L.; Yi, A.; Simakov, A. N.; Haan, S. W.; Batha, S. H.; Dewald, E. L.; Rygg, J. R.; Tommasini, R.; Xu, H.; Kong, C.; Bae, J.; Rice, N.

    2017-02-01

    For the first time, 41Ar produced by the (n,ϒ) reaction from 40Ar in the beryllium shell of a DT filled Inertial Confinement Fusion capsule has been measured. Ar is co-deposited with beryllium in the sputter deposition of the capsule shell. Combined with a measurement of the neutron yield, the radioactive 41Ar then quantifies the areal density of beryllium during the DT neutron production. The measured 1.15 ± 0.17 × 10+8 atoms of 41Ar are 2.5 times that from the best post-shot calculation, suggesting that the Ar and Be areal densities are correspondingly higher than those calculated. Possible explanations are that (1) the beryllium shell is compressed more than calculated, (2) beryllium has mixed into the cold DT ice, or more likely (3) less beryllium is ablated than calculated. Since only one DT filled beryllium capsule has been fielded at NIF, these results can be confirmed and expanded in the future.

  3. Growth of fluorocarbon macromolecules in the gas phase: IV. Li{sup +}-attachment mass spectrometric investigation of high-mass neutral radicals in the downstream region of Ar/c-C{sub 4}F{sub 8} plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, Hiroshi; Furuya, Kenji; Harata, Akira, E-mail: furuya@mm.kyushu-u.ac.j [Department of Molecular and Material Sciences, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan)

    2009-03-21

    Mass analysis has been conducted on neutral species in the downstream region of Ar/c-C{sub 4}F{sub 8} plasmas by Li{sup +}-attachment mass spectrometry. Various peaks appeared in the mass spectrum observed in the case of 29% c-C{sub 4}F{sub 8}, and many of them have unambiguously been assigned to the Li{sup +} adducts of neutral radicals with odd-numbered fluorine atoms from 2n + 1 to 2n - 5, where n means the number of carbon atoms, as well as neutral species with even-numbered fluorine atoms from 2n + 2 to 2n - 10. In contrast, only the peaks due to C{sub n}F{sub 2n+2} (n = 1-7), C{sub n}F{sub 2n} (n = 1, 4-8), C{sub n}F{sub 2n-2} (n = 3, 5-8) and C{sub 9}F{sub 14} appeared in the case of 2.2% c-C{sub 4}F{sub 8}. These findings demonstrate that the Li{sup +}-attachment ionization is fragment-free, not only for relatively stable perfluorocarbon species but also for their neutral radicals, and therefore effective for the identification of high-mass neutral perfluorocarbon radicals. The analysis of the growth mechanisms of C{sub n}F{sub 2n+2} and C{sub n}F{sub 2n} on the basis of thermochemistry has proposed CF{sub 3}CF as an important reactant.

  4. The dynamic response of carbon fiber-filled polymer composites

    OpenAIRE

    Patterson B.; Orler E.B.; Furmanski J.; Rigg P.A.; Scharff R.J.; Stahl D.B.; Sheffield S.A.; Gustavsen R.L.; Dattelbaum D.M.; Coe J.D.

    2012-01-01

    The dynamic (shock) responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE) composite to 18.6 GPa in the through-thickness direction,...

  5. Study on Antigravity Mold Filling by Conservative Scalar Method

    Institute of Scientific and Technical Information of China (English)

    李日; 王友序; 杨根仓; 毛协民

    2003-01-01

    By SIMPLE method and Van-Leer scheme, a program on numerical simulation for 3D mold filling has been developed. The fluid flow field of gas and liquid is calculated in couples by a single phase N-S equation using SIMPLE method, and free surface control equation is handied by Van-Leer scheme. Then it is verified by an anti-gravity mold filling of thin wall plate. In order to demonstrate its ability to simulate 3D casting, an anti-gravity mould filling of a cube is computed by the program.

  6. ar

    Directory of Open Access Journals (Sweden)

    P. Fanlo

    Full Text Available A pesar de que el pulmón es el órgano diana por excelencia de la tuberculosis, cualquier otro órgano y sistema puede verse afectado. En este trabajo se revisan las formas de tuberculosis extrapulmonar a excepción de la pleural que requieren del facultativo, en ocasiones, su más valiosa pericia diagnóstica. Desde la temida meningitis tuberculosa, pasando por la afectación insidiosa de la espondilodiscitis, la llamativa afectación ganglionar, la afectación genitourinaria, la pericarditis, para terminar las formas menos frecuentes como la ocular o la cutánea. En cada apartado indicaremos lo más característico con la finalidad de que pueda servir de orientación diagnóstica y terapéutica.

  7. A scintillating gas detector for 2D dose measurements in clinical carbon beams.

    Science.gov (United States)

    Seravalli, E; de Boer, M; Geurink, F; Huizenga, J; Kreuger, R; Schippers, J M; van Eijk, C W E; Voss, B

    2008-09-07

    A two-dimensional position sensitive dosimetry system based on a scintillating gas detector has been developed for pre-treatment verification of dose distributions in hadron therapy. The dosimetry system consists of a chamber filled with an Ar/CF4 scintillating gas mixture, inside which two cascaded gas electron multipliers (GEMs) are mounted. A GEM is a thin kapton foil with copper cladding structured with a regular pattern of sub-mm holes. The primary electrons, created in the detector's sensitive volume by the incoming beam, drift in an electric field towards the GEMs and undergo gas multiplication in the GEM holes. During this process, photons are emitted by the excited Ar/CF4 gas molecules and detected by a mirror-lens-CCD camera system. Since the amount of emitted light is proportional to the dose deposited in the sensitive volume of the detector by the incoming beam, the intensity distribution of the measured light spot is proportional to the 2D hadron dose distribution. For a measurement of a 3D dose distribution, the scintillating gas detector is mounted at the beam exit side of a water-bellows phantom, whose thickness can be varied in steps. In this work, the energy dependence of the output signal of the scintillating gas detector has been verified in a 250 MeV/u clinical 12C ion beam by means of a depth-dose curve measurement. The underestimation of the measured signal at the Bragg peak depth is only 9% with respect to an air-filled ionization chamber. This is much smaller than the underestimation found for a scintillating Gd2O2S:Tb ('Lanex') screen under the same measurement conditions (43%). Consequently, the scintillating gas detector is a promising device for verifying dose distributions in high LET beams, for example to check hadron therapy treatment plans which comprise beams with different energies.

  8. Secondary scintillation in Ar-CF$_4$ mixtures

    CERN Document Server

    Beschi, Andrea

    2015-01-01

    In order to build a optical time projection chamber that can be used as a tracking detector, it is necessary to study the scintillation proprieties of gases in order to optimize the light emission. A detailed study of the scintillation of Ar-CF$_4$ mixtures at different concentrations has been performed to study the light emission of the gas in a triple GEM detector.

  9. Ars Industrialis, arsindustrialis.org

    Directory of Open Access Journals (Sweden)

    Frédérique Mingant

    2012-03-01

    Full Text Available The arsindustrialis.org website was created in 2005, when the association Ars Industrialis came into being. The association was founded by a group of philosophers and jurists, on the initiative of philosopher Bernard Stiegler, the former director of the IRCAM (Institut de Recherche et Coordination Acoustique/Musique–Institute of Research and Coordination on Acoustic/Music and the current director of the Department of cultural development at the Centre Georges Pompidou (French National Arts C...

  10. Ars Industrialis, arsindustrialis.org

    OpenAIRE

    Frédérique Mingant

    2012-01-01

    The arsindustrialis.org website was created in 2005, when the association Ars Industrialis came into being. The association was founded by a group of philosophers and jurists, on the initiative of philosopher Bernard Stiegler, the former director of the IRCAM (Institut de Recherche et Coordination Acoustique/Musique–Institute of Research and Coordination on Acoustic/Music) and the current director of the Department of cultural development at the Centre Georges Pompidou (French National Arts C...

  11. ARS - Helsinki - 2006 / Galina Balashova

    Index Scriptorium Estoniae

    Balashova, Galina

    2006-01-01

    Steven Holli projekteeritud Kiasma muuseumihoonest Helsingis. Kontseptuaalkunsti näitusest ARS 06 "Reaalsustunne" Kiasmas. Eestlastest esineb Mark Raidpere. Vene kunstnikegrupi AEC+F ja vene kunstnike Juri Vassiljevi ning Aleksandr Ponomarjovi töödest näitusel. Ka Gerda Steineri & Jörg Lenzlingeri (Šveits), Martin & Munoz'i (USA, Hispaania), arvutigraafik Charles Sandisoni (SB), videokunstnik Bill Viola (USA) jt. töödest

  12. Discovery of underground argon with low level of radioactive 39Ar and possible applications to WIMP dark matter detectors

    CERN Document Server

    Galbiati, C

    2007-01-01

    We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be <=4x10-17 (84% C.L.), less than 5% the value in atmospheric argon (39Ar/Ar=8x10-16). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.

  13. Atmospheric Ar and Ne returned from mantle depths to the Earth's surface by forearc recycling.

    Science.gov (United States)

    Baldwin, Suzanne L; Das, J P

    2015-11-17

    In subduction zones, sediments, hydrothermally altered lithosphere, fluids, and atmospheric gases are transported into the mantle, where ultrahigh-pressure (UHP) metamorphism takes place. However, the extent to which atmospheric noble gases are trapped in minerals crystallized during UHP metamorphism is unknown. We measured Ar and Ne trapped in phengite and omphacite from the youngest known UHP terrane on Earth to determine the composition of Ar and Ne returned from mantle depths to the surface by forearc recycling. An (40)Ar/(39)Ar age [7.93 ± 0.10 My (1σ)] for phengite is interpreted as the timing of crystallization at mantle depths and indicates that (40)Ar/(39)Ar phengite ages reliably record the timing of UHP metamorphism. Both phengite and omphacite yielded atmospheric (38)Ar/(36)Ar and (20)Ne/(22)Ne. Our study provides the first documentation, to our knowledge, of entrapment of atmospheric Ar and Ne in phengite and omphacite. Results indicate that a subduction barrier for atmospheric-derived noble gases does not exist at mantle depths associated with UHP metamorphism. We show that the crystallization age together with the isotopic composition of nonradiogenic noble gases trapped in minerals formed during subsolidus crystallization at mantle depths can be used to unambiguously assess forearc recycling of atmospheric noble gases. The flux of atmospheric noble gas entering the deep Earth through subduction and returning to the surface cannot be fully realized until the abundances of atmospheric noble gases trapped in exhumed UHP rocks are known.

  14. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.

    2014-04-01

    The benefits of filling carbon nanotubes (CNTs) with assorted molecular and crystalline substances have been investigated for the past two decades. Amongst the study of new structural phases, defects, chemical reactions and varied types of host-guest interactions, there is one fundamental characterisation aspect of these systems that continues to be overlooked: the mechanical behaviour of filled CNTs. In contrast to their empty counterparts, the mechanics of filled CNTs is a subject where reports appear far and apart, this despite being key to the application of these materials in technological devices. In the following paragraphs, we review the work that has been carried out up to the present on the mechanics of filled CNTs. The studies discussed range from experimental resonant frequency essays performed within electron microscopes to modelling, via molecular dynamics, of three-point bending of nanotubes filled with gases. (C) 2014 Elsevier B.V. All rights reserved.

  15. Occurrences of Excess 40Ar in Hydrothermal Tourmaline:Interpretations from 40Ar-39Ar Dating Results by Stepwise Heating

    Institute of Scientific and Technical Information of China (English)

    QIU Huaning; PU Zhiping; DAI Tongmo

    2007-01-01

    The occurrences of excess 40Ar within a hydrothermal tourmaline is discussed in term of the analysis data of syngenetic muscovite and tourmaline from the Lushui hydrothermal tin-tungsten deposit in western Yunnan, China, using the 40Ar-39Ar stepwise heating technique. About 80% excess 40Ar was released in the last step when the tourmaline was fused, corresponding to a release of only ~3% 39Ar (K), which indicates that most excess 40Ar was held in the mineral lattice rather than in the channels parallel to the Z-axis. This suggests that the excess 40Ar was incorporated during crystallization and not diffused into the tourmaline during the post-crystallization history.

  16. Ars Memorativa, Ars Oblivionis in Middle English Religious Plays

    Directory of Open Access Journals (Sweden)

    Ciobanu Estella Antoaneta

    2015-12-01

    Full Text Available This paper investigates the multi-layered violence of religious representation in the late medieval York biblical plays, with a focus on the Supper at Emmaus. I read Emmaus (Y40, a play which commemorates the Crucifixion and openly encourages strong anti-Judaism, alongside scenes in an early predecessor pageant, The Crucifixion (Y35, within their contemporary devotional and mnemonic practices, i.e. the confessional Book of Margery Kempe and Thomas Bradwardine’s tract on ars memorativa. Emmaus in particular demonstrates how a fundamentally violent ars memorativa, the legacy of ancient rhetoric to the Middle Ages, also underpins the instruction of the laity in the basics of Christian faith, here with the aid of highly musical prosody and repetition, and thereby hones a biased, intolerant and violence-inured Christian collective memory. To study the York play’s position relative to late medieval mnemonic practices, I frame my analysis within memory studies, enriched with the more specific insights offered by social-psychological, neurobiological and cognitivist studies of memory.

  17. PF-AR upgrading project

    CERN Document Server

    Kasuga, T

    2002-01-01

    The upgrading project of the dedicated pulse X-ray source PF-AR has been completed by the end of the 2001 fiscal year. Machine commissioning exclusively using the injector linac was successfully accomplished in the beginning of January 2002. After fine tuning of the machine and cleaning of the vacuum system with the beams from the middle of January to the middle of March, routine operation for users has begun in April. The historical details, commissioning and results of the project are reported. (author)

  18. Effects of Pt speedlayer and Ar pressure on magnetic and structural properties of sputtered CoNi/Pt multilayers

    NARCIS (Netherlands)

    Meng, Q.; Haan, de P.; Drent, van W.P.; Lodder, J.C.; Popma, Th.J.A.

    1996-01-01

    CoNi/Pt multilayers were prepared by magnetron sputtering using Ar gas. The effects of the Pt seed layer and the Ar sputtering pressure on magnetic and structural properties are investigated. Microstructures of the multilayers were analysed using XRD and TEM. It was found that perpendicular magnetic

  19. Safety Injection System Filling Using Dynamic Venting

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Je; Kim, Wong Bae; Huh, Jin; Lee, Joo Hee; Im, In Young; Kim, Eun kee [KEPCO Engineering and Construction Company, Daejeon (Korea, Republic of)

    2015-05-15

    In the APR+, the water-level elevation of the in-containment refueling water storage tank (IRWST) is lower than the highest piping of the SIS. Since the gravity filling of water from IRWST cannot fill all SIS piping, an SIP or an SCP test line is newly provided in order to allow the dynamic venting of the SIS. NEI 09-10 Revision 1a-A has concluded that use of dynamic venting is an effective means to remove gas from local high points and traps in piping when correctly based on the dynamic flow rate, void volume, Floude number, and the system water volume. In this study, feasibility of the dynamic vent is investigated. The work presented in this study evaluates the SIS and the SCS filling using the dynamic venting which is supposed to be applied to the APR+. The main ideas are as follows; 1. Dynamic venting using SIPs for the APR+ is not appropriate on the basis of 12 inches in diameter and with the flow rate, 1,460 gpm. 2. Because the high point of the SIS and the SCS is located at the piping that the two systems are sharing, the accumulated gas at the highest point can be removed by using the SCPs, and the dimension of the new piping will be determined by its length of them and the number of elbows. The calculated results are shown in Table 2. 3. The applicability of the dynamic venting methods using the SCPs that are mentioned above should be evaluated in the aspect of the system operation after the piping arrangements are settled in the APR+. The assessments to determine the pump operation time are also required.

  20. Removal of root filling materials.

    LENUS (Irish Health Repository)

    Duncan, H.F. Chong, B.S.

    2011-05-01

    Safe, successful and effective removal of root filling materials is an integral component of non-surgical root canal re-treatment. Access to the root canal system must be achieved in order to negotiate to the canal terminus so that deficiencies in the original treatment can be rectified. Since a range of materials have been advocated for filling root canals, different techniques are required for their removal. The management of commonly encountered root filling materials during non-surgical re-treatment, including the clinical procedures necessary for removal and the associated risks, are reviewed. As gutta-percha is the most widely used and accepted root filling material, there is a greater emphasis on its removal in this review.

  1. Laser vision based adaptive fill control system for TIG welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The variation of joint groove size during tungsten inert gas (TIG) welding will result in the non-uniform fill of deposited metal. To solve this problem, an adaptive fill control system was developed based on laser vision sensing. The system hardware consists of a modular development kit (MDK) as the real-time image capturing system, a computer as the controller, a D/A conversion card as the interface of controlled variable output, and a DC TIG welding system as the controlled device. The system software is developed and the developed feature extraction algorithm and control strategy are of good accuracy and robustness. Experimental results show that the system can implement adaptive fill of melting metal with high stability, reliability and accuracy. The groove is filled well and the quality of the weld formation satisfies the relevant industry criteria.

  2. Ar-40/Ar-39 age determinations for the Rotoiti eruption, New Zealand

    Science.gov (United States)

    Flude, S.; Storey, M.

    2013-12-01

    The contemporaneous Rotoiti and Earthquake Flat ignimbrites, erupted from the Taupo Volcanic zone, New Zealand, form a distinctive tephrostratigraphic horizon in the Southern Pacific. Radioisotopic dating results for these eruptions remain controversial, with published ages ranging from 35.1 × 2.8 ka [1] to 71 × 6 ka [2], with 61.0 × 1.5 ka [3] often being cited as the most widely accepted age. These eruptions are difficult to date as their age is near the limit for various radiometric dating techniques, which are complicated by a large proportion of inherited material (xenocrysts) and a lack of phases suitable for dating. Glass-bearing plutonic blocks erupted with the Rotoiti and Earthquake Flat ignimbrites have previously been interpreted as deriving from a slowly cooled and incompletely solidified magma body that was sampled by the eruptions. They contain large vugs lined with euhedral quartz, sanidine and biotite crystals, indicating that these crystals grew in a gas or aqueous fluid rich environment and are interpreted to have formed shortly before or during eruption. Here we will present Ar-40/Ar-39 ages for sanidines and biotites extracted from vugs in lithic blocks erupted as part of the Earthquake Flat ignimbrite. We show that, even for vug-lining material, inherited ages remain a problem and are the likely source of the wide variation in published radiometric ages. Nevertheless, many of the Ar-40/Ar-39 ages are much younger than the 61 ka age [3] and are more consistent with the recent stratigraphic, C-14 and U-238/Th-230+(U-Th)/He ages that have been suggested (e.g. [4,5]). 1. Whitehead, N. & Ditchburn, R. New Zealand Journal of Geology and Geophysics 37, 381-383 (1994). 2. Ota, Y., Omura, A. & Iwata, H. New Zealand Journal of Geology and Geophysics 32, 327-331 (1989). 3. Wilson, C. J. N. et al. Quaternary Science Reviews 26, 1861-1870 (2007). 4. Molloy, C., Shane, P. & Augustinus, P. Geological Society of America Bulletin 121, 1666-1677 (2009). 5

  3. Production of Ar metastables in a dielectric barrier discharge

    Science.gov (United States)

    Mikheyev, Pavel A.; Han, Jiande; Clark, Amanda; Sanderson, Carl; Heaven, Michael C.

    2017-01-01

    The results of experiments with a dielectric barrier discharge (DBD) are presented, where the production of metastable argon atoms was studied. The recently proposed optically pumped all-rare-gas laser (OPRGL) utilizes metastable atoms of heavier rare gases as lasing species. The required number density of metastables for efficient laser operation is 1012÷1013 cm-3 in an atmospheric pressure of He buffer gas. Recent experiments had shown that such densities are easily produced in a nanosecond pulsed discharge, even at pressures larger than atmospheric, but problems appear when one is trying to produce them in a CW regime. The reason for difficulties in the CW production of metastables at an atmospheric pressure seems to be the low value of the E/N parameter (DBD in 2-5% Ar mixture with He at an atmospheric pressure was studied. [Ar(1s5)] number density of the order of 1012 cm-3 was readily achieved. Temporal behavior of [Ar(1s5)] throughout the DBD cycle was obtained. The results demonstrate the feasibility of DBDs for OPRGL development.

  4. REACTOR FILLED WITH CATALYST MATERIAL, AND CATALYST THEREFOR

    NARCIS (Netherlands)

    Sie, S.T.

    1995-01-01

    Abstract of WO 9521691 (A1) Described is a reactor (1) at least partially filled with catalyst granules (11), which is intended for catalytically reacting at least one gas and at least one liquid with each other. According to the invention the catalyst granules (11) are collected in agglomerates

  5. Interpretation of discordant 40Ar/39Ar age-spectra of mesozoic tholeiites from antarctica

    Science.gov (United States)

    Fleck, R.J.; Sutter, J.F.; Elliot, D.H.

    1977-01-01

    Conventional K-Ar ages of tholeiitic basalts of the Ferrar Group in the central Transantarctic Mountains indicate significant loss of radiogenic 40Ar from this unit over much of its outcrop area. Argon loss varies inversely with amount of devitrified matrix in the basalts, which have not been thermally or tectonically disturbed since extrusion. 40Ar/19Ar age-spectra of these tholeiites are generally discordant and indicate significant inhomogeneity in the distribution of radiogenic 40Ar with respect to 39Ar, but are distinctly different from release patterns of thermally disturbed samples. Amounts of argon redistribution vary directly with amounts of devitrification and are reflected in progressive modification of the age spectra. A model of redistribution of radiogenic 40Ar by devitrification of originally glassy matrix is suggested that is consistent with disturbance of the conventional K-Ar systematics as well as the 40Ar/39Ar age-spectra. Samples with substantial redistribution but minor loss of radiogenic argon yield age spectra whose apparent ages decrease from low-temperature to high-temperature steps, similar to those reported for some lunar basalts, breccias, and soils. Modification of all the age spectra is attributed to redistribution of radiogenic 40Ar during progressive devitrification, although 39Ar-recoil effects suggested by Turner and Cadogan (1974) may be a factor in some cases. Where devitrification involves most potassium sites within the basalt, 40Ar/39Ar age-plateaux may be formed that have no geologic significance. ?? 1977.

  6. A house with its own filling station; Das Haus mit der eigenen Tankstelle

    Energy Technology Data Exchange (ETDEWEB)

    Stadelmann, M.

    2005-07-01

    This short article describes how a house in Erlinsbach, Switzerland was rebuilt and, at the same time, fitted with a new gas-fired heating system - and with its own natural gas filling station. The history behind this unusual project is discussed. The inclusion of a filling station in the project made it worthwhile for the gas utility to lay a connection from the gas mains to the house. The economic advantages for its builder, who sells such natural gas filling station equipment, are mentioned. The consumption of the natural gas used as motor fuel is measured and taxed separately. Equivalent fuel costs are now said by the owner to be already below today's petrol prices and will become even lower when the planned reduction of levies on such use of natural gas come into force.

  7. Thermal plasma properties for Ar-Al, Ar-Fe and Ar-Cu mixtures used in welding plasmas processes: I. Net emission coefficients at atmospheric pressure

    Science.gov (United States)

    Cressault, Y.; Gleizes, A.

    2013-10-01

    This article is devoted to the calculation of the net emission coefficient (NEC) of Ar-Al, Ar-Fe and Ar-Cu mixtures at atmospheric pressure for arc welding processes. The results are given in data tables for temperatures between 3 kK and 30 kK, for five plasma thicknesses (0, 0.5, 1, 2, 5 mm) and ten concentrations of metallic vapours (pure gas, 0.01%, 0.1%, 1%, 5%, 10%, 25%, 50%, 75% and pure metal vapours in mass proportions). The results are in good agreement with most of the works published on the subject for such mixtures. They highlight the influence of three parameters on the radiation of the plasma: the NEC is directly related to temperature and inversely related to plasma radius and is highly sensitive to the presence of metal vapours. Finally, numerical data are supplied in tables in order to develop accurate computational modelling of welding arc and to estimate both qualitatively and quantitatively the influence of each metallic vapour on the size and on the shape of the weld pool.

  8. Pneumatically sprayed Cu2ZnSnS4 films under Ar and Ar-H2 atmosphere

    Science.gov (United States)

    Espindola Rodriguez, M.; Sylla, D.; Sanchez, Y.; López-Marino, S.; Fontané, X.; López-García, J.; Placidi, M.; Pérez-Rodríguez, A.; Vigil-Galán, O.; Saucedo, E.

    2014-06-01

    Cu2ZnSnS4 (CZTS) thin films have been deposited by pneumatic spray pyrolysis onto soda-lime glass and Mo-coated glass substrates by using a special reactor designed for working under controlled atmospheres. The films were grown using both Ar and Ar-H2 as the carrier gas and atmosphere, aiming to eliminate the oxygen-containing atmosphere from the classical spray pyrolysis configuration that uses air as the carrier gas. Thin films with different compositions were prepared and thermally annealed to investigate its compositional and physical properties and its performance as absorber layers in solar cells. To know the impact of the thermal annealing, two different annealing temperatures were used: 550 and 580 °C, both for 30 min. The last temperature showed a great improvement in the crystallinity and allowed a better incorporation of Sn into the films. The optical band gap of the annealed films was found to be around 1.45 eV. Cu-S and ZnO were found as contaminant phases in the as-grown Ar-sprayed samples, but were effectively transformed after annealing. ZnS was detected in both the as-grown and annealed films as the main secondary phase. Solar cells free of scarce elements were fabricated showing an improved conversion efficiency of 1.4%, evidencing the higher potential of this approach for the synthesis of device-grade films.

  9. Mars Atmospheric History Derived from Upper-Atmospheric Structure of 38Ar/36Ar Measured From MAVEN

    Science.gov (United States)

    Jakosky, Bruce; Slipski, Marek; Benna, Mehdi; Mahaffy, Paul; Elrod, Meredith K.; Yelle, Roger; Stone, Shane; Alsaeed, Noora

    2016-10-01

    Measurements of the structure of the Martian upper atmosphere made from MAVEN observations allow us to derive homopause and exobase altitudes in the Mars upper atmosphere and to determine the isotopic fractionation that occurs between them. Fractionation in the ratio of 38Ar/36Ar occurs between the homopause and exobase due to diffusive separation. This fractionation, combined with measurements of the bulk atmospheric ratio, is used to determine the total amount of argon lost to space by pick-up-ion sputtering. Our analysis is based on Rayleigh distillation, modified by replenishment of gas to the atmosphere by outgassing, impact, and crustal weathering. Approximately 80 % of the 36Ar that was ever in the atmosphere has been removed through time. This high value requires that a major fraction of Mars atmospheric gas has been lost to space. It points strongly to loss to space as having been the dominant mechanism driving the transition in Martian climate from an early, warm, wet environment to today's cold, dry, thin atmosphere.

  10. Ars grammatica de Dionisio Tracio

    Directory of Open Access Journals (Sweden)

    Beltrán Jorge Enrique

    2003-06-01

    Full Text Available

    Ars Grammatica de Dionisio Tracio (170-90 a. C fue la primera gramática griega que se escribió. Su contenido y método fueron modelos que siguieron las gramáticas escolares posteriores. La versión española que se presenta ahora responde a la necesidad que se tenía en nuestro medio de una traducción completa de este texto. Finalmente, se acompaña la traducción de una introducción y de abundantes notas, en un intento por hacerla comprensible para el hablante del español, no necesariamente conocedor de la lengua griega.

  11. Time Dependant Weld Shape in Ar-O2 Shielded Stationary GTA Welding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The stationary gas tungsten arc welding (GTA) is carried out on SUS304 stainless steel under Ar-0.1%O2 and Ar-0.3%O2 mixed shielding to observe the evolution of the molten pool and investigate the role of Marangoni convection on the weld shape. After welding, the oxygen content in the weld metal was measured by using an oxygen/nitrogen analyzer. Small addition of oxygen to the argon based shielding gas can effectively adjust the weld pool oxygen content. Oxygen plays an important role as an surface active element in determining the pattern of Marangoni convection in the stainless steel weld pool. When the weld metal oxygen content is over the critical value, 0.01 wt pet, corresponding to the Ar-0.3%O2 mixed shielding gas, the Marangoni convection changes from outward to inward direction and the weld shape dramatically changes from wide shallow shape to narrow deep shape.

  12. Development of a Low-Level Ar-37 Calibration Standard

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Richard M.; Aalseth, Craig E.; Bowyer, Ted W.; Day, Anthony R.; Fuller, Erin S.; Haas, Derek A.; Hayes, James C.; Hoppe, Eric W.; Humble, Paul H.; Keillor, Martin E.; LaFerriere, Brian D.; Mace, Emily K.; McIntyre, Justin I.; Miley, Harry S.; Myers, Allan W.; Orrell, John L.; Overman, Cory T.; Panisko, Mark E.; Seifert, Allen

    2016-03-07

    Argon-37 is an important environmental signature of an underground nuclear explosion. Producing and quantifying low-level 37Ar standards is an important step in the development of sensitive field measurement instruments for use during an On-Site Inspection, a key provision of the Comprehensive Nuclear-Test-Ban Treaty. This paper describes progress at Pacific Northwest National Laboratory (PNNL) in the development of a process to generate and quantify low-level 37Ar standard material, which can then be used to calibrate sensitive field systems at activities consistent with soil background levels. The 37Ar used for our work was generated using a laboratory-scale, high-energy neutron source to irradiate powdered samples of calcium carbonate. Small aliquots of 37Ar were then extracted from the head space of the irradiated samples. The specific activity of the head space samples, mixed with P10 (90% stable argon:10% methane by mole fraction) count gas, is then derived using the accepted Length-Compensated Internal-Source Proportional Counting method. Due to the low activity of the samples, a set of three Ultra-Low Background Proportional-Counters designed and fabricated at PNNL from radio-pure electroformed copper was used to make the measurements in PNNL’s shallow underground counting laboratory. Very low background levels (<10 counts/day) have been observed in the spectral region near the 37Ar emission feature at 2.8 keV. Two separate samples from the same irradiation were measured. The first sample was counted for 12 days beginning 28 days after irradiation, the second sample was counted for 24 days beginning 70 days after irradiation (the half-life of 37Ar is 35.0 days). Both sets of measurements were analyzed and yielded very similar results for the starting activity (~0.1 Bq) and activity concentration (0.15 mBq/ccSTP argon) after P10 count gas was added. A detailed uncertainty model was developed based on the ISO Guide to the Expression of Uncertainty in

  13. XRD-based 40Ar/39Ar age correction for fine-grained illite, with application to folded carbonates in the Monterrey Salient (northern Mexico)

    Science.gov (United States)

    Fitz-Díaz, Elisa; Hall, Chris M.; van der Pluijm, Ben A.

    2016-05-01

    Due to their minute size, 40Ar/39Ar analysis of illite faces significant analytical challenges, including mineral characterization and, especially, effects of grain size and crystallography on 39Ar recoil. Quantifying the effects of 39Ar recoil requires the use of sample vacuum encapsulation during irradiation, which permits the measurement of the fraction of recoiled 39Ar as well as the 39Ar and 40Ar∗ retained within illite crystals that are released during step heating. Total-Gas Ages (TGA) are calculated by using both recoiled and retained argon, which is functionally equivalent to K-Ar ages, while Retention Ages (RA) only involve retained Ar in the crystal. Natural applications have shown that TGA fits stratigraphic constraints of geological processes when the average illite crystallite thickness (ICT) is smaller than 10 nm, and that RA matches these constraints for ICTs larger than 50 nm. We propose a new age correction method that takes into account the average ICT and corresponding recoiled 39Ar for a sample, with X-ray Corrected Ages (XCA) lying between Total-Gas and Retention Ages depending on ICT. This correction is particularly useful in samples containing authigenic illite formed in the anchizone, with typical ICT values between 10 and 50 nm. In three samples containing authigenic illite from Cretaceous carbonates in the Monterrey Salient in northern Mexico, there is a range in TGAs among the different size-fractions of 46-49, 36-43 and 40-52 Ma, while RAs range from 54-64, 47-52 and 53-54 Ma, respectively. XCA calculations produce tighter age ranges for these samples of 52.5-56, 45.5-48.5 and 49-52.5 Ma, respectively. In an apparent age vs ICT or %2M 1illite plot, authigenic illite grains show a slope that is in general slightly positive for TGA, slightly negative for RA, but close to zero for XCA, with thinner crystallites showing more dispersion than thicker ones. In order to test if dispersion is due to a different formation history or the result

  14. Effect of gas pressure on ionization of ambient gas

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An Nd: YAG pulsed laser (145 mJ) was used to ablate aluminum target and Ar was used as protecting gas. Time-and space-resolved spectra of the plasmas under pressure 100 Pa, 1 kPa, 10 kPa and 100 kPa were acquired with time- and space-resolved technique. The characteristics of the plasma radiating under each pressure were briefly described, and the laws of Ar characteristical radiaton were analyzed in detail. Based on the profile of Ar characteristical radiation under these pressure, the relation between protecting gas pressure and its ionization was briefly discussed, and explained with quantum theory. Farther more, the mechanism of ambient gas ionization was investigated. As the result, it was suggested that the main mechanism inducing protecting gas to ionize should be the absorption of the plasma continuum radiation by the gas.

  15. Excitation of 6 sup minus and 7 sup + stretched states in the sup 38 Ar( p , n ) sup 38 K reaction at 135 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, B.D.; Baldwin, A.R.; Garcia, L.A.C.; Madey, R.; Manley, D.M.; Pourang, R.; Steinfelds, E.; Watson, J.W. (Department of Physics, Kent State University, Kent, Ohio 44242 (United States)); Brown, J.D.; Jacobsen, E.R.; Sherr, R. (Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)); Brown, B.A. (Department of Physics, Michigan State University, East Lansing, Michigan 48824 (United States)); Foster, C.C. (Indiana University Cyclotron Facility, Bloomington, Indiana 47405 (United States))

    1992-08-01

    High-spin, stretched-state excitations were studied in the {sup 38}Ar({ital p},{ital n}){sup 38}K reaction at 135 MeV with the beam-swinger system at the Indiana University Cyclotron Facility. Neutron kinetic energies were measured by the time-of-flight technique with large-volume plastic-scintillator neutron detectors at flight paths ranging from 81 to 131 m. Overall time resolutions of about 825 ps provided energy resolutions from 320 to 450 keV. The target was a 4-cm-long gas cell filled to {similar to}3 atm absolute. Angular distributions were extracted for the low-lying excitations observed at wide angles. A known 7{sup +} state at {ital E}{sub {ital x}}=3.5 MeV was observed, plus two states at 5.3 and 5.9 MeV, which are tentatively identified as 6{sup {minus}} excitations, based on comparisons with distorted wave Born approximation and {ital sdpf} shell-model calculations. The {sup 38}K spectrum is in reasonable agreement with the shell-model calculations. In contrast to the analysis of 80 MeV {sup 40}Ca({ital d},{alpha}){sup 38}Ar measurements, these results do not indicate a significant problem for the nuclear shell model near {ital A}=40.

  16. Fluid circulation and reservoir conditions of the Los Humeros Geothermal Field (LHGF), Mexico, as revealed by a noble gas survey

    Science.gov (United States)

    Pinti, Daniele L.; Castro, M. Clara; Lopez-Hernandez, Aida; Han, Guolei; Shouakar-Stash, Orfan; Hall, Chris M.; Ramírez-Montes, Miguel

    2017-03-01

    Los Humeros Geothermal Field (LHGF) is one of four geothermal fields currently operating in Mexico, in exploitation since 1990. Located in a caldera complex filled with very low-permeability rhyolitic ignimbrites that are the reservoir cap-rock, recharge of the geothermal field is both limited and localized. Because of this, planning of any future geothermal exploitation must be based on a clear understanding of the fluid circulation. To this end, a first noble gas survey was carried out in which twenty-two production wells were sampled for He, Ne, Ar, Kr, and Xe isotope analysis. Air-corrected 3He/4He ratios (Rc) measured in the fluid, normalized to the helium atmospheric ratio (Ra; 1.384 × 10- 6), are consistently high across the field, with an average value of 7.03 ± 0.40 Ra. This value is close to that of the sub-continental upper mantle, indicating that LHGF mines heat from an active magmatic system. Freshwater recharge does not significantly affect He isotopic ratios, contributing 1-10% of the total fluid amount. The presence of radiogenic 40Ar* in the fluid suggests a fossil fluid component that might have circulated within the metacarbonate basement with radiogenic argon produced from detrital dispersed illite. Solubility-driven elemental fractionation of Ne/Ar, Kr/Ar, and Xe/Ar confirm extreme boiling in the reservoir. However, a combined analysis of these ratios with 40Ar/36Ar reveals mixing with an air component, possibly introduced by re-injected geothermal fluids.

  17. 3c/4e [small sigma, Greek, circumflex]-type long-bonding competes with ω-bonding in noble-gas hydrides HNgY (Ng = He, Ne, Ar, Kr, Xe, Rn; Y = F, Cl, Br, I): a NBO/NRT perspective.

    Science.gov (United States)

    Zhang, Guiqiu; Li, Hong; Weinhold, Frank; Chen, Dezhan

    2016-03-21

    Noble-gas hydrides HNgY are frequently described as a single ionic form (H-Ng)(+)Y(-). We apply natural bond orbital (NBO) and natural resonance theory (NRT) analyses to a series of noble-gas hydrides HNgY (Ng = He, Ne, Ar, Kr, Xe, Rn; Y = F, Cl, Br, I) to gain quantitative insight into the resonance bonding of these hypervalent molecules. We find that each of the studied species should be better represented as a resonance hybrid of three leading resonance structures, namely, H-Ng(+ -):Y (I), H:(- +)Ng-Y (II), and H^Y (III), in which the "ω-bonded" structures I and II arise from the complementary donor-acceptor interactions nY → σ*HNg and nH → σ*NgY, while the "long-bond" ([small sigma, Greek, circumflex]-type) structure III arises from the nNg → [small sigma, Greek, circumflex]*HY/[small sigma, Greek, circumflex]HY interaction. The bonding for all of the studied molecules can be well described in terms of the continuously variable resonance weightings of 3c/4e ω-bonding and [small sigma, Greek, circumflex]-type long-bonding motifs. Furthermore, we find that the calculated bond orders satisfy a generalized form of "conservation of bond order" that incorporates both ω-bonding and long-bonding contributions [viz., (bHNg + bNgY) + bHY = bω-bonding + blong-bonding = 1]. Such "conservation" throughout the title series implies a competitive relationship between ω-bonding and [small sigma, Greek, circumflex]-type long-bonding, whose variations are found to depend in a chemically reasonable manner on the electronegativity of Y and the outer valence-shell character of the central Ng atom. The calculated bond orders are also found to exhibit chemically reasonable correlations with bond lengths, vibrational frequencies, and bond dissociation energies, in accord with Badger's rule and related empirical relationships. Overall, the results provide electronic principles and chemical insight that may prove useful in the rational design of noble-gas hydrides of

  18. Paleovalley fills: Trunk vs. tributary

    Science.gov (United States)

    Kvale, E.P.; Archer, A.W.

    2007-01-01

    A late Mississippian-early Pennsylvanian eustatic sea level drop resulted in a complex lowstand drainage network being eroded across the Illinois Basin in the eastern United States. This drainage system was filled during the early part of the Pennsylvanian. Distinct differences can be recognized between the trunk and tributary paleovalley fills. Fills preserved within the trunk systems tend to be fluvially dominated and consist of bed-load deposits of coarse- to medium-grained sandstone and conglomerate. Conversely, the incised valleys of tributary systems tend to be filled with dark mudstone, thinly interbedded sandstones, and mudstones and siltstones. These finer grained facies exhibit marine influences manifested by tidal rhythmites, certain traces fossils, and macro- and microfauna. Examples of tributary and trunk systems, separated by no more than 7 km (4.3 mi) along strike, exhibit these styles of highly contrasting fills. Useful analogs for understanding this Pennsylvanian system include the Quaternary glacial sluiceways present in the lower Ohio, White, and Wabash river valleys of Indiana (United States) and the modern Amazon River (Brazil). Both the Amazon River and the Quaternary rivers of Indiana have (or had) trunk rivers that are (were) dominated by large quantities of bed load relative to their tributaries. The trunk valley systems of these analogs aggraded much more rapidly than their tributary valleys, which evolved into lakes because depositional rates along the trunk are (were) so high that the mouths of the tributaries have been dammed by bed-load deposits. These Holocene systems illustrate that sediment yields can significantly influence the nature of fill successions within incised valleys independent of rates of sea level changes or proximity to highstand coastlines. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

  19. XeCl Avalanche discharge laser employing Ar as a diluent

    Science.gov (United States)

    Sze, Robert C.

    1981-01-01

    A XeCl avalanche discharge exciplex laser which uses a gaseous lasing starting mixture of: (0.2%-0.4% chlorine donor/2.5%-10% Xe/97.3%-89.6% Ar). The chlorine donor normally comprises HCl but can also comprise CCl.sub.4 BCl.sub.3. Use of Ar as a diluent gas reduces operating pressures over other rare gas halide lasers to near atmospheric pressure, increases output lasing power of the XeCl avalanche discharge laser by 30% to exceed KrF avalanche discharge lasing outputs, and is less expensive to operate.

  20. QENS investigation of filled rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Triolo, A.; Lechner, R.E.; Desmedt, A.; Pieper, J. [CNR - Istituto per i Processi Chimico-Fisici, sez. Messina, Via La Farina 237, 98123 Messina (Italy); Lo Celso, F.; Triolo, R. [Dip. Chimica Fisica, V. le delle Scienze, Parco d' Orleans, Padiglione 17, Universita di Palermo, 90128 Palermo (Italy); Negroni, F. [Pirelli Pneumatici S.p.A, V. le Sarca 222, 20126 Milano (Italy); Arrighi, V.; Qian, H. [Chemistry School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS Edinburgh (United Kingdom); Frick, B. [Institut Laue-Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble, Cedex 9 (France)

    2002-07-01

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

  1. QENS investigation of filled rubbers

    CERN Document Server

    Triolo, A; Desmedt, A; Pieper, J K; Lo Celso, F; Triolo, R; Negroni, F; Arrighi, V; Qian, H; Frick, B

    2002-01-01

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

  2. QENS investigation of filled rubbers

    Science.gov (United States)

    Triolo, A.; Lo Celso, F.; Negroni, F.; Arrighi, V.; Qian, H.; Lechner, R. E.; Desmedt, A.; Pieper, J.; Frick, B.; Triolo, R.

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface.

  3. 祁漫塔格韧性剪切带中绢云母40Ar-39Ar定年及地质意义%40Ar-39Ar Dating of the Muscovite in the Sericite of the Qimantage Ductile Shear Zone and Its Geological Significance

    Institute of Scientific and Technical Information of China (English)

    郭通珍; 谈生祥; 常革红; 丁玉进; 张志青

    2012-01-01

    Qimantage ductile shear zone is the main tectonic boundary of Qimantage ophiolite belt and North Kunlun magmatic arc, we determine granitic mylonite in shear zone with sericite 40Ar-39 Ar meth-ods. Plateau age is 271. 1 ± 2. 2Ma,36 Ar/40 Ar-39 Ar/40 Ar reverse-isochron curve age is 270. 5 ± 3. 7 Ma (MSWD=2.7), and 39Ar/36Ar-40Ar/36Ar isochron age is 270.9±4.7Ma (MSWD = 0.22) . Plateau age 271. 1±2. 2Ma close to the age of mineral formation of sericite, it represents the formation age of Qiman-tage ductile shear zone. Through the ductile shear zone within the kinematic characteristics, dextral shear zone has the nature of Oblique filling. The formation of Qimantage ductile shear zone related Paleo-Tethys Ocean Subduction, is the remote effects of the process of Paleo-Tethys Ocean Northward subduction orog-eny.%祁漫塔格韧性剪切带是祁漫塔格蛇绿混杂岩带与北昆仑岩浆弧的区域主构造边界,对剪切带内花岗质糜棱岩中绢云母40Ar-39 Ar法年龄测定,获得了(271.1±2.2) Ma的坪年龄,相应的36Ar/40 Ar-39 Ar/40 Ar反等时线年龄为(270.5±3.7)Ma (MSWD=2.7),39Ar/36 Ar-40 Ar/35 Ar正等时线年龄为(270.9±4.7) Ma (MSWD=0.22);坪年龄(271.1±2.2) Ma接近于绢云母矿物的形成年龄,也代表了祁漫塔格韧性剪切带的形成年龄.通过韧性剪切变形带内运动学特征的研究,表明剪切带具有右旋斜冲的性质.祁漫塔格韧性剪切带的形成与古特提斯洋的俯冲作用有关,是古特提斯洋向北俯冲造山过程的远程效应.

  4. Fluid/Gas Process Controller

    Science.gov (United States)

    Ramos, Sergio

    1989-01-01

    Fluid/gas controller, or "Super Burper", developed to obtain precise fill quantities of working fluid and noncondensable gas in heat pipe by incorporating detachable external reservoir into system during processing stage. Heat pipe filled with precise quantities of working fluid and noncondensable gas, and procedure controlled accurately. Application of device best suited for high-quality, high performance heat pipes. Device successfully implemented with various types of heat pipes, including vapor chambers, thermal diodes, large space radiators, and sideflows.

  5. Study of the symbiotic star AR Pavonis

    Directory of Open Access Journals (Sweden)

    C. Quiroga

    2001-01-01

    Full Text Available We present a study of the optical spectra and linear polarization of the eclipsing binary AR Pavonis. The optical spectra were obtained between 1990 and 1998, and polarimetric data between 1995 and 1998. From spectroscopic variations along the orbital motion we analized the nature of the system. Polarimetric studies indicate that AR Pav has intrinsic polarization.

  6. Membrane lipid composition of pancreatic AR42J cells: modification by exposure to different fatty acids.

    Science.gov (United States)

    Audi, Nama'a; Mesa, María D; Martínez, María A; Martínez-Victoria, Emilio; Mañas, Mariano; Yago, María D

    2007-04-01

    Dietary fat type influences fatty acids in rat pancreatic membranes, in association with modulation of secretory activity and cell signalling in viable acini. We aimed to confirm whether AR42J cells are a valid model to study the interactions between lipids and pancreatic acinar cell function. For this purpose we have (i) compared the baseline fatty acid composition of AR42J cells with that of pancreatic membranes from rats fed a standard chow; (ii) investigated if fatty acids in AR42J membranes can be modified in culture; and (iii) studied if similar compositional variations that can be evoked in rats when dietary fat type is altered occur in AR42J cells. Weaning Wistar rats were fed for 8 weeks either a commercial chow (C) or semi-purified diets containing virgin olive oil (VOO) or sunflower oil (SO) as fat source. AR42J cells were incubated for 72 hrs in medium containing unmodified fetal calf serum (FCS, AR42J-C cells), FCS enriched with 18:1 n-9 (AR42J-O cells), or FCS enriched with 18:2 n-6 (AR42J-L cells). Fatty acids in crude membranes from rat pancreas and AR42J cells were determined by gas-liquid chromatography. Differences in membrane fatty acids between C rats and AR42J-C cells can be explained in part by variations in the amount of fatty acids in the extracellular environment. Supplementation of FCS with 18:1 n-9 or 18:2 n-6 changed the fatty acid spectrum of AR42J cells in a manner that resembles the pattern found, respectively, in VOO and SO rats, although AR42J-L cells were unable to accumulate 20:4 n-6. The AR42J cell line can be a useful tool to assess the effect of membrane compositional changes on acinar cell function. However, differences in baseline characteristics, and perhaps fatty acid metabolism, indicate that results obtained in AR42J cells should be confirmed with experiments in the whole animal.

  7. Noble gases solubility models of hydrocarbon charge mechanism in the Sleipner Vest gas field

    Science.gov (United States)

    Barry, P. H.; Lawson, M.; Meurer, W. P.; Warr, O.; Mabry, J. C.; Byrne, D. J.; Ballentine, C. J.

    2016-12-01

    Noble gases are chemically inert and variably soluble in crustal fluids. They are primarily introduced into hydrocarbon reservoirs through exchange with formation waters, and can be used to assess migration pathways and mechanisms, as well as reservoir storage conditions. Of particular interest is the role groundwater plays in hydrocarbon transport, which is reflected in hydrocarbon-water volume ratios. Here, we present compositional, stable isotope and noble gas isotope and abundance data from the Sleipner Vest field, in the Norwegian North Sea. Sleipner Vest gases are generated from primary cracking of kerogen and the thermal cracking of oil. Gas was emplaced into the Sleipner Vest from the south and subsequently migrated to the east, filling and spilling into the Sleipner Ost fields. Gases principally consist of hydrocarbons (83-93%), CO2 (5.4-15.3%) and N2 (0.6-0.9%), as well as trace concentrations of noble gases. Helium isotopes (3He/4He) are predominantly radiogenic and range from 0.065 to 0.116 RA; reported relative to air (RA = 1.4 × 10-6; Clarke et al., 1976; Sano et al., 1988), showing predominantly (>98%) crustal contributions, consistent with Ne (20Ne/22Ne from 9.70 to 9.91; 21Ne/22Ne from 0.0290 to 0.0344) and Ar isotopes (40Ar/36Ar from 315 to 489). Air-derived noble gas isotopes (20Ne, 36Ar, 84Kr, 132Xe) are introduced into the hydrocarbon system by direct exchange with air-saturated water (ASW). The distribution of air-derived noble gas species are controlled by phase partitioning processes; in that they preferentially partition into the gas (i.e., methane) phase, due to their low solubilities in fluids. Therefore, the extent of exchange between hydrocarbon phases and formation waters - that have previously equilibrated with the atmosphere - can be determined by investigating air-derived noble gas species. We utilize both elemental ratios to address process (i.e., open vs. closed system) and concentrations to quantify the extent of hydrocarbon

  8. Aging Studies of Filled and Unfilled VCE

    Energy Technology Data Exchange (ETDEWEB)

    Letant, S; Herberg, J; Alviso, C; Small, W; Mulcahy, H; Pearson, M; Wilson, T; Chinn, S; Maxwell, R

    2009-11-10

    This report presents data on the effects of temperature and gamma radiation on the chemical and structural properties of both filled and unfilled VCE material produced by the Kansas City Plant using WR-qualified processes. Thermal effects up to 300 C and gamma irradiation doses of 1 MRad and 25 MRad were investigated under atmospheric conditions. Characterization techniques used in the study comprise Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Tensile Testing, Solid Phase MicroExtraction - Gas Chromatography/Mass Spectrometry (SPME-GC/MS), phenol extraction followed by HPLC, and various Nuclear Magnetic Resonance (NMR) techniques including: {sup 13}C, {sup 13}C {l_brace}{sup 1}H{r_brace} cross polarization (CP), {sup 1}H magic angle spinning (MAS), 13C{l_brace}{sup 1}H{r_brace} Wide-line-Separation (2D-WISE) and development of Center band-Only Detection of Exchange (CODEX).

  9. Numerical simulation and analysis of mould filling process in lost foam casting

    Institute of Scientific and Technical Information of China (English)

    Jiang Junxia; Wu Zhichao; Chen Liliang; Hao Jing

    2008-01-01

    In lost foam casting (LFC) the foam pattern is the key criterion, and the filling process is crucial to ensure the high quality of the foam pattern. Filling which lacks uniformity and denseness will cause various defects and affect the surface quality of the casting. The influential factors of the filling process are realized in this research. Optimization of the filling process, enhancement of efficiency, decrease of waste, etc., are obtained by the numerical simulation of the filling process using a computer. The equations governing the dense gas-solid two-phase flow are established, and the physical significance of each equation is discussed. The Euler/Lagrange numerical model is used to simulate the fluid dynamic characteristics of the dense two-phase flow during the mould filling process in lost foam casting. The experiments and numerical results showed that this method can be a very promising tool in the mould filling simulation of beads' movement.

  10. Analysis of Ar line spectra from indirectly-driven implosion experiments on SGII facility

    Institute of Scientific and Technical Information of China (English)

    Pu Yu-Dong; Zhang Ji-Yan; Yang Jia-Min; Huang Tian-Xuan; Ding Yong-Kun

    2011-01-01

    This paper reports on the indirectly-driven implosion experiments on SGII laser facility in which Ar emission spectrum from Ar-doped D-filled plastic capsule is recorded with the crystal spectrometer. Spectral features of Ar Heβ line and its associated satellites are analysed to extract the electron temperature and density of the implosion core. Non local thermal equilibrium (NLTE) collisional-radiative atomic kinetics and Strark broadening line shape are included in the present calculation. By comparing the calculated spectrum with the measured one, the core electron temperature and density are inferred to be 700 eV and 2.5 × 1023 cm-3 respectively. With these inferred values of electron temperature and density, neutron yield can be estimated to agree with the measured value in magnitude despite of the very simple model used for the estimation.

  11. The Coronae of AR Lac

    CERN Document Server

    Huenemoerder, D P; Drake, J J; Sanz-Forcada, J; Canizares, Claude R.; Drake, Jeremy J.; Huenemoerder, David P.; Sanz-Forcada, Jorge

    2003-01-01

    We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and conjunctions. Contemporaneous and simultaneous EUV spectra and photometry were also obtained with the Extreme Ultraviolet Explorer. Significant variability in both X-ray and EUV fluxes were observed, dominated by at least one X-ray flare and one EUV flare. We saw no evidence of primary or secondary eclipses. X-ray flux modulation was largest at high temperature, indicative of flare heating of coronal plasma. Line widths interpreted in terms of Doppler broadening suggest that both binary stellar components are active. From line fluxes obtained from total integrated spectra, we have modeled the emission measure and abundance distributions. A strong maximum was found in the differential emission measure, characterized by peaks at log T = 6.9 and 7.4, together with a weak but significant cooler maximum near log T=6.2, and a moderately str...

  12. Filling of charged cylindrical capillaries

    NARCIS (Netherlands)

    Das, Siddhartha; Chanda, Sourayon; Eijkel, J.C.T.; Tas, N.R.; Chakraborty, Suman; Mitra, Sushanta K.

    2014-01-01

    We provide an analytical model to describe the filling dynamics of horizontal cylindrical capillaries having charged walls. The presence of surface charge leads to two distinct effects: It leads to a retarding electrical force on the liquid column and also causes a reduced viscous drag force because

  13. Filling in the retinal image

    Science.gov (United States)

    Larimer, James; Piantanida, Thomas

    1990-01-01

    The optics of the eye form an image on a surface at the back of the eyeball called the retina. The retina contains the photoreceptors that sample the image and convert it into a neural signal. The spacing of the photoreceptors in the retina is not uniform and varies with retinal locus. The central retinal field, called the macula, is densely packed with photoreceptors. The packing density falls off rapidly as a function of retinal eccentricity with respect to the macular region and there are regions in which there are no photoreceptors at all. The retinal regions without photoreceptors are called blind spots or scotomas. The neural transformations which convert retinal image signals into percepts fills in the gaps and regularizes the inhomogeneities of the retinal photoreceptor sampling mosaic. The filling-in mechamism plays an important role in understanding visual performance. The filling-in mechanism is not well understood. A systematic collaborative research program at the Ames Research Center and SRI in Menlo Park, California, was designed to explore this mechanism. It was shown that the perceived fields which are in fact different from the image on the retina due to filling-in, control some aspects of performance and not others. Researchers have linked these mechanisms to putative mechanisms of color coding and color constancy.

  14. Unsteady Capillary Filling By Electrocapillarity

    Science.gov (United States)

    Kang, In Seok; Lee, Jung A.

    2016-11-01

    Unsteady filling of electrolyte solution inside a nanochannel by the electrocapillarity effect is studied. The filling rate is predicted as a function of the bulk concentration of the electrolyte, the surface potential (or surface charge density), and the cross sectional shape of the channel. Since the driving force of the flow is the electrocapillarity, it is first analyzed by using the solution of the Poisson-Boltzmann equation. From the analysis, it is found that the results for many different cross sectional shapes can be unified with good accuracy if the hydraulic radius is adopted as the characteristic length scale of the problem. Especially in the case of constant surface potential, for both limits of κh -> 0 and κh -> ∞ , it can be shown theoretically that the electrocapillarity is independent of the cross sectional shape if the hydraulic radius is the same. In order to analyze the geometric effects more systematically, we consider the regular N-polygons with the same hydraulic radius and the rectangles of different aspect ratios. Washburn's approach is then adopted to predict the filling rate of electrolyte solution inside a nanaochannel. It is found that the average filling velocity decreases as N increases in the case of regular N-polygons with the same hydraulic radius. This is because of that the regular N-polygons of the same hydraulic radius share the same inscribing circle. This work has been supported by BK21+ program.

  15. 40Ar/39Ar ages of lunar impact glasses: Relationships among Ar diffusivity, chemical composition, shape, and size

    CERN Document Server

    Zellner, N E B

    2015-01-01

    Lunar impact glasses, quenched melts produced during cratering events on the Moon, have the potential to provide not only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 landing sites indicate that retention of radiogenic 40Ar is a strong function of post-formation thermal history in the lunar regolith, size, and chemical composition. Based on the relationships presented in this paper, lunar impact glasses with compositions and sizes sufficient to have retained 90% of their radiogenic Ar during 750 Ma of cosmic ray exposure at time-integra...

  16. Calibration of an ultra-low-background proportional counter for measuring 37Ar

    Science.gov (United States)

    Seifert, A.; Aalseth, C. E.; Bonicalzi, R. M.; Bowyer, T. W.; Day, A. R.; Fuller, E. S.; Haas, D. A.; Hayes, J. C.; Hoppe, E. W.; Humble, P. H.; Keillor, M. E.; LaFerriere, B. D.; Mace, E. K.; McIntyre, J. I.; Merriman, J. H.; Miley, H. S.; Myers, A. W.; Orrell, J. L.; Overman, C. T.; Panisko, M. E.; Williams, R. M.

    2013-08-01

    An ultra-low-background proportional counter design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electro-chemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with 14C/3H, age-dating of groundwater with 39Ar, and soil-gas assay for 37Ar to support On-Site Inspection (OSI). On-Site Inspection is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of 37Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of 37Ar samples over a broad range of proportional counter operating pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for 37Ar soil gas background studies.

  17. 40Ar/39Ar Ages of Carbonaceous Xenoliths in 2 HED Meteorites

    Science.gov (United States)

    Turrin, B.; Lindsay, F. N.; Park, J.; Herzog, G. F.; Delaney, J. S.; Swisher, C. C., III; Johnson, J.; Zolensky, M.

    2016-01-01

    The generally young K/Ar and 40Ar/39Ar ages of CM chondrites made us wonder whether carbonaceous xenoliths (CMX) entombed in Howardite–Eucrite–Diogenite (HED) meteorites might retain more radiogenic 40Ar than do ‘free-range’ CM-chondrites. To find out, we selected two HED breccias with carbonaceous inclusions in order to compare the 40Ar/39Ar release patterns and ages of the inclusions with those of nearby HED material. Carbonaceous inclusions (CMXs) in two HED meteorites lost a greater fraction of radiogenic 40Ar than did surrounding host material, but a smaller fraction of it than did free-range CM-chondrites such as Murchison or more heavily altered ones. Importantly, however, the siting of the CMXs in HED matrix did not prevent the 40Ar loss of about 40 percent of the radiogenic 40Ar, even from phases that degas at high laboratory temperatures. We infer that carbonaceous asteroids with perihelia of 1 astronomical unit probably experience losses of at least this size. The usefulness of 40Ar/39Ar dating for samples returned from C-type asteroids may hinge, therefore, on identifying and analyzing separately small quantities of the most retentive phases of carbonaceous chondrites.

  18. Evaluation of sintering effects on SiC-incorporated UO2 kernels under Ar and Ar-4%H2 environments

    Science.gov (United States)

    Silva, Chinthaka M.; Lindemer, Terrence B.; Hunt, Rodney D.; Collins, Jack L.; Terrani, Kurt A.; Snead, Lance L.

    2013-11-01

    Silicon carbide (SiC) is suggested as an oxygen getter in UO2 kernels used for tristructural isotropic (TRISO) particle fuels and to prevent kernel migration during irradiation. Scanning electron microscopy and X-ray diffractometry analyses performed on sintered kernels verified that an internal gelation process can be used to incorporate SiC in UO2 fuel kernels. Even though the presence of UC in either argon (Ar) or Ar-4%H2 sintered samples suggested a lowering of the SiC up to 3.5-1.4 mol%, respectively, the presence of other silicon-related chemical phases indicates the preservation of silicon in the kernels during sintering process. UC formation was presumed to occur by two reactions. The first was by the reaction of SiC with its protective SiO2 oxide layer on SiC grains to produce volatile SiO and free carbon that subsequently reacted with UO2 to form UC. The second process was direct UO2 reaction with SiC grains to form SiO, CO, and UC. A slightly higher density and UC content were observed in the sample sintered in Ar-4%H2, but both atmospheres produced kernels with ˜95% of theoretical density. It is suggested that incorporating CO in the sintering gas could prevent UC formation and preserve the initial SiC content.

  19. LHCB RICH gas system proposal

    CERN Document Server

    Bosteels, Michel; Haider, S

    2001-01-01

    Both LHCb RICH will be operated with fluorocarbon as gas radiator. RICH 1 will be filled with 4m^3 of C4F10 and RICH 2 with 100m^3 of CF4. The gas systems will run as a closed loop circulation and a gas recovery system within the closed loop is planned for RICH 1, where the recovery of the CF4 will only be realised during filling and emptying of the detector. Inline gas purification is foreseen for the gas systems in order to limit water and oxygen impurities.

  20. Aging measurements with the gas electron multiplier (GEM)

    CERN Document Server

    Altunbas, M C; Kappler, S; Ketzer, B; Ropelewski, Leszek; Sauli, Fabio; Simon, F

    2003-01-01

    Continuing previous aging measurements with detectors based on the Gas Electron Multiplier (GEM), a $31\\times 31$cm$^2$ triple-GEM detector, as used in the small area tracking of the COMPASS experiment at CERN, was investigated. With a detector identical to those installed in the experiment, long-term, high-rate exposures to $8.9$keV X-ray radiation were performed to study its aging properties. In standard operation conditions, with Ar:CO$_2$ (70:30) filling and operated at an effective gain of $8.5\\cdot 10^3$, no change in gain and energy resolution is observed after collecting a total charge of 7mC/mm$^2$, corresponding to seven years of normal operation. This observation confirms previous results demonstrating the relative insensitivity of GEM detectors to aging, even when manufactured with common materials.

  1. Ars Baltica-verkoston puheenjohtajuus Suomeen Risto Ruohoselle

    Index Scriptorium Estoniae

    1999-01-01

    1990. a. loodud võrgustiku Ars Baltica sekretariaat (Ars Baltica Contact Point & Communication Center) tuleb Kielist Tallinnasse Eesti kultuuriministeeriumi kuni aastani 2002 (Suur-Karja 23). Ars Baltica (ühendus)

  2. Filling high aspect ratio trenches by superconformal chemical vapor deposition: Predictive modeling and experiment

    Science.gov (United States)

    Wang, Wenjiao B.; Abelson, John R.

    2014-11-01

    Complete filling of a deep recessed structure with a second material is a challenge in many areas of nanotechnology fabrication. A newly discovered superconformal coating method, applicable in chemical vapor deposition systems that utilize a precursor in combination with a co-reactant, can solve this problem. However, filling is a dynamic process in which the trench progressively narrows and the aspect ratio (AR) increases. This reduces species diffusion within the trench and may drive the component partial pressures out of the regime for superconformal coating. We therefore derive two theoretical models that can predict the possibility for filling. First, we recast the diffusion-reaction equation for the case of a sidewall with variable taper angle. This affords a definition of effective AR, which is larger than the nominal AR due to the reduced species transport. We then derive the coating profile, both for superconformal and for conformal coating. The critical (most difficult) step in the filling process occurs when the sidewalls merge at the bottom of the trench to form the V shape. Experimentally, for the Mg(DMADB)2/H2O system and a starting AR = 9, this model predicts that complete filling will not be possible, whereas experimentally we do obtain complete filling. We then hypothesize that glancing-angle, long-range transport of species may be responsible for the better than predicted filling. To account for the variable range of species transport, we construct a ballistic transport model. This incorporates the incident flux from outside the structure, cosine law re-emission from surfaces, and line-of-sight transport between internal surfaces. We cast the transport probability between all positions within the trench into a matrix that represents the redistribution of flux after one cycle of collisions. Matrix manipulation then affords a computationally efficient means to determine the steady-state flux distribution and growth rate for a given taper angle. The

  3. Stratigraphy and Ar/Ar geochronology of the Miocene lignite-bearing Tunçbilek-Domaniç Basin, western Anatolia

    Science.gov (United States)

    Helvacı, C.; Ersoy, E. Y.; Billor, M. Z.

    2016-08-01

    The Tunçbilek-Domaniç Basin is one of the Neogene basins containing economic coal deposits in western Anatolia, Turkey. The basin fill represents fluvial to lacustrine sedimentary units which are interlayered with volcanic rocks with bimodal composition. In order to reveal the stratigraphy and the exact ages of the basin fill and coal deposits, and to explore the tectonic evolution of the basin, we present new field data and Ar/Ar age data from the volcanic units. The field studies and the age data indicate that the whole basin fills were deposited between ~23 and ~19 Ma (Aquitanian-Early Burdigalian) without any unconformity. Taking into account the ages of the coal-bearing sedimentary units in the other Neogene basins in the region, it is concluded that most of the economic coal deposits in the western Anatolia were formed during Aquitanian. The field studies also show that the deposition of the sedimentary units in the basin was controlled by the NE-SW-trending strike- to oblique-slip normal faults. In a regional scale, tectonic evolution of the Tunçbilek-Domaniç Basin is linked to the differential stretching in the hanging wall of the southerly located, a crustal-scale low-angle detachment fault (the Simav detachment fault) that controlled the Early Miocene exhumation of the Menderes Extensional Core Complex.

  4. Formation of KrCl * and ArCl * molecules and radiative lifetimes of their B states investigated with selective synchrotron radiation excitation

    Science.gov (United States)

    Castex, M. C.; Le Calvé, J.; Haaks, D.; Jordan, B.; Zimmerer, G.

    1980-02-01

    Monochromatic pulsed VUV excitation of Cl 2 or inert gas atoms in Cl 2 doped Kr and Ar leads to formation of KrCl * and ArCl *. The radiative lifetimes of the B states (KrCl * 19 ns, ArCl * 9 ns) and rate constants for excimer formation, quenching and collisional mixing of B and C states are given. The radiative lifetime and the quenching rate increase with vibrational excitation of the B state (KrCl *).

  5. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  6. Numerical simulation of mould filling process for pressure plate and valve handle in LFC

    Directory of Open Access Journals (Sweden)

    Jiang Junxia

    2010-11-01

    Full Text Available In lost foam casting (LFC, the distribution of polymer beads during the bead filling process is not uniform, and the collision between polymer beads determines the distribution of two-phase flow of gas and solid. The interaction between the gas and solid phases reveals as coupling effect of the force that gas exerts on particles or vice versa, or that among particles. The gas-solid flow in filling process is nonlinearity, which makes the coupling effect an essential point to carry out a simulation properly. Therefore, information of each particle’s motion is important for acquiring the law of filling process. In bead filling process, compressed air is pressed into mold cavity, and discharged from gas vent, creating a pressure difference between outer and inner space near the gas vent. This pressure difference directly changes the spatial distribution and motion trace of gas and solid phases. In this paper, Discrete Element Method (DEM and Computational Fluid Dynamics (CFD are employed to simulate the fluid dynamic character based on Newton’s Third Law of Motion. The simulation results of some casting products such as pressure plate and valve handle are compared with the result obtained from practical experiment in order to test the feasibility of DEM. The comparison shows that this DEM method can be a very promising tool in the mould filling simulation of beads’ movement.

  7. Paleoclimate change in the Nakuru basin, Kenya, at 119 - 109 ka derived from δ18Odiatom and diatom assemblages and 40Ar/39Ar geochronology

    Science.gov (United States)

    Bergner, Andreas; Deino, Alan; Leng, Melanie; Gasse, Francoise

    2016-04-01

    A 4.5m-thick diatomite bed deposited during the cold interval of the penultimate interglacial at ~119 - 109 ka documents a period in which a deep freshwater lake filled the Nakuru basin in the Central Kenya Rift (CKR), East Africa. Palaeohydrological conditions of the basin are reconstructed for the paleolake highstand using δ18Odiatom and characterization of diatom assemblages. The age of the diatomite deposit is established by precise 40Ar/39Ar-dating of intercalated pumice tuffs. The paleolake experienced multiple hydrological fluctuations on sub-orbital (~1,500 to 2,000 years) time scales. The magnitude of the δ18Odiatom change (+/- 3‰) and significant changes in the plankton-littoral ratio of the diatom assemblage (+/- 25%) suggest that the paleolake record can be interpreted in the context of long-term climatic change in East Africa. Using 40Ar/39Ar age control and nominal diatomite-sedimentation rates we establish a simplified age model of paleohydrological vs. climatic change, from which we conclude that more humid conditions prevailed in equatorial East Africa during the late Pleistocene over a relatively long time interval of several thousands years. Then, extreme insolation at eccentricity maximum and weakened zonal air-pressure gradients in the tropics favored intensified ITCZ-like convection over East Africa and deep-freshwater lake conditions.

  8. ARS 01 Helsingi Kiasmas / Tarmo Virki

    Index Scriptorium Estoniae

    Virki, Tarmo

    2001-01-01

    Helsingis Kiasmas avatud rahvusvahelisest kunstinäitusest ARS 01 alapealkirjaga "Avanevaid perspektiive", kus esines oma töödega ka Marko Mäetamm. Näituse raames toimuvast Santiago Sierra kunstiprojektist kodututega

  9. "Ars Ornata" Mediterrania / Kadri Mälk

    Index Scriptorium Estoniae

    Mälk, Kadri, 1958-

    1999-01-01

    VI rahvusvaheline ehtekunstinäitus "Ars Ornata" juuni lõpus Barcelonas. Konverentsist, peanäitusest (osalejad Eestist), ehtekunstiõpetust andvast kõrgkoolist Escola Massana'st Barcelonas, õppejõude. Eesti ehtekunsti tulevikust.

  10. Differential AR algorithm for packet delay prediction

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Different delay prediction algorithms have been applied in multimedia communication, among which linear prediction is attractive because of its low complexity. AR (auto regressive) algorithm is a traditional one with low computation cost, while NLMS (normalize least mean square) algorithm is more precise. In this paper, referring to ARIMA (auto regression integrated with moving averages) model, a differential AR algorithm (DIAR) is proposed based on the analyses of both AR and NLMS algorithms. The prediction precision of the new algorithm is about 5-10 db higher than that of the AR algorithm without increasing the computation complexity.Compared with NLMS algorithm, its precision slightly improves by 0.1 db on average, but the algorithm complexity reduces more than 90%. Our simulation and tests also demonstrate that this method improves the performance of the average end-to-end delay and packet loss ratio significantly.

  11. Ars ornata / Kadri Mälk

    Index Scriptorium Estoniae

    Mälk, Kadri, 1958-

    1998-01-01

    V rahvusvaheline ehtekunsti konverents 'Ars ornata Europeana' juuni lõpus Stockholmis. New Yorgis elava kuraatori Charon Kranseni ja prantsuse ehtekunstniku Christophe Burger' juhitud vestlusringidest. 1997. a. Pariisis loodud International Craft Design Association'ist (ICDA).

  12. Ar and Kr concentrations in nitrogen as a measure of the 39Ar and 85Kr activities in connection with the solar neutrino experiment BOREXINO.

    Science.gov (United States)

    Zuzel, G; Simgen, H; Heusser, G

    2004-01-01

    Among other radionuclides, 39Ar and 85Kr are potential background sources in the solar neutrino detector BOREXINO. The expected low event rate requires that the nitrogen used in the experiment needs to have lower concentrations than 0.5 microBq/m3 for 39Ar and 0.2 microBq/m3 for 85Kr, corresponding to volume concentrations in N2 of 0.4 x 10(-6)m3/m3 for Ar and 0.2 x 10(-12)m3/m3 for Kr. Applying gas mass spectrometry and special care in the sampling technique we succeeded in finding the required purity. In addition, we studied the possibility to purify nitrogen from Kr by the adsorption method.

  13. ArF准分子激光系统的能量效率特性∗%Energy efficiency analysis of ArF excimer laser system

    Institute of Scientific and Technical Information of China (English)

    王倩; 赵江山; 罗时文; 左都罗; 周翊

    2016-01-01

    为深入理解ArF准分子激光系统的运转机制,进而获得优化ArF准分子激光系统设计的理论及方向性指导,利用一维流体模型,以气体高压放电等离子体深紫外激光辐射过程为主要对象,研究了放电抽运ArF准分子激光系统的动力学特性,梳理了ArF准分子激光系统的能量传递过程,深入研究了等离子体放电机理,从能量沉积效率、ArF∗粒子形成过程、激光输出三个方面,分析了动力学过程中影响能量效率的主要因素,提出了相应的改进优化措施。仿真结果表明,氟气及相关粒子在系统运转过程中有重要作用,工作气体中氟气的组分比例对能量效率影响较大,偏离最佳点会导致激光系统能量效率的下降。相关结论为ArF准分子激光系统的优化设计和稳定可靠运转提供了重要的理论参考依据。%The reliable functioning and continual optimizing of ArF excimer laser system is of importance when it comes to productization into the market from a laboratory test machine. The analysis of dynamic characteristics of the system is vital to understanding its operating mechanism and optimizing the design theoretically. In this article, one-dimensional fluid model is used to analyze the excimer laser discharge mechanism, and the content ratio of fluorine gas, argon gas, and neon gas, which constitute a gas mixture, is studied in a simulated ArF excimer laser system. Particles are treated as a fluid, which significantly reduces the computing cost in fluid model, and therefore is suitable for high-pressure situation. Four equations are included in one-dimensional fluid model, i.e., Boltzmann equation that describes electron energy distribution, ion continue equation that illustrates ion number density, Poisson’s equation that shows the distribution of electric field, and photon rate equation that demonstrates laser outputting process. By combining these four equations, high

  14. NEW ACCURATE MEASUREMENT OF {sup 36}ArH{sup +} AND {sup 38}ArH{sup +} RO-VIBRATIONAL TRANSITIONS BY HIGH RESOLUTION IR ABSORPTION SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Cueto, M.; Herrero, V. J.; Tanarro, I.; Doménech, J. L. [Molecular Physics Department, Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, E-28006 Madrid (Spain); Cernicharo, J. [Department of Astrophysics, CAB. INTA-CSIC. Crta Torrejón-Ajalvir Km 4, E-28850 Torrejón de Ardoz, Madrid (Spain); Barlow, M. J.; Swinyard, B. M., E-mail: jl.domenech@csic.es [Department of Physics and Astronomy, University College London. Gower Street, London WC1E 6BT (United Kingdom)

    2014-03-01

    The protonated argon ion, {sup 36}ArH{sup +}, was recently identified in the Crab Nebula from Herschel spectra. Given the atmospheric opacity at the frequency of its J = 1-0 and J = 2-1 rotational transitions (617.5 and 1234.6 GHz, respectively), and the current lack of appropriate space observatories after the recent end of the Herschel mission, future studies on this molecule will rely on mid-infrared observations. We report on accurate wavenumber measurements of {sup 36}ArH{sup +} and {sup 38}ArH{sup +} rotation-vibration transitions in the v = 1-0 band in the range 4.1-3.7 μm (2450-2715 cm{sup –1}). The wavenumbers of the R(0) transitions of the v = 1-0 band are 2612.50135 ± 0.00033 and 2610.70177 ± 0.00042 cm{sup –1} (±3σ) for {sup 36}ArH{sup +} and {sup 38}ArH{sup +}, respectively. The calculated opacity for a gas thermalized at a temperature of 100 K and with a linewidth of 1 km s{sup –1} of the R(0) line is 1.6 × 10{sup –15} × N({sup 36}ArH{sup +}). For column densities of {sup 36}ArH{sup +} larger than 1 × 10{sup 13} cm{sup –2}, significant absorption by the R(0) line can be expected against bright mid-IR sources.

  15. Filling of carbon nanotubes and nanofibres

    Directory of Open Access Journals (Sweden)

    Reece D. Gately

    2015-02-01

    Full Text Available The reliable production of carbon nanotubes and nanofibres is a relatively new development, and due to their unique structure, there has been much interest in filling their hollow interiors. In this review, we provide an overview of the most common approaches for filling these carbon nanostructures. We highlight that filled carbon nanostructures are an emerging material for biomedical applications.

  16. Laser propagation through full-scale, high-gain MagLIF gas pipes using the NIF

    Science.gov (United States)

    Pollock, Bradley; Sefkow, Adam; Goyon, Clement; Strozzi, David; Khan, Shahab; Rosen, Mordy; Campbell, Mike; Logan, Grant; Peterson, Kyle; Moody, John

    2016-10-01

    The first relevant measurements of laser propagation through surrogate high-gain MagLIF gas pipe targets at full scale have been performed at the NIF, using 30 kJ of laser drive from one quad in a 10 ns pulse at an intensity of 2e14 W/cm2. The unmagnetized pipe is filled with 1 atm of 99%/1% neopentane/Ar, and uses an entrance window of 0.75 um polyimide and an exit window of 0.3 um of Ta backed with 5 um of polyimide. Side-on x-ray emission from the plasma is imaged through the 100 um-thick epoxy wall onto a framing camera at four times during the drive, and is in excellent agreement with pre-shot HYDRA radiation-hydrodynamics modeling. X-ray emission from the Ta exit plane is imaged onto a streak camera to determine the timing and intensity of the laser burning through the pipe, and the Ar emission from the center of the pipe is spectrally- and temporally-resolved to determine the plasma electron temperature. Backscatter is measured throughout the laser drive, and is found to be of significance only when the laser reaches the Ta exit plane and produces SBS. These first results in unmagnetized surrogate gas fills are encouraging since they demonstrate sufficient laser energy absorption and low LPI losses within high-density long-scale-length plasmas for proposed high-gain MagLIF target designs. We will discuss plans to magnetize targets filled with high-density DT gas in future experiments. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  17. A novel gas-filled detector for synchrotron radiation applications

    Energy Technology Data Exchange (ETDEWEB)

    Kocsis, Menyhert [ESRF BP 220 38043 Grenoble (France)]. E-mail: kocsis@esrf.fr; Boesecke, P. [ESRF BP 220 38043 Grenoble (France); Carbone, D. [ESRF BP 220 38043 Grenoble (France); Herve, C. [ESRF BP 220 38043 Grenoble (France); Becker, B. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Diawara, Y. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Durst, R. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Khazins, D. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); He, B. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Medved, S. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Sedov, V. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Thorson, T. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Wachter, G. [Bruker AXS, Inc 5465 East Cheryl Parkway, Madison, WI 53711 (United States)

    2006-07-01

    We describe in this paper the performance under synchrotron radiation of a sealed gaseous detector, Vantec-1, operating at high pressure and less prone to discharges. It is consequently operating at high gain (>10{sup 5}) at high local counting rates up to 10{sup 6} cps/mm{sup 2}. To achieve these characteristics, a thin resistive layer is used on a glass plate between the mesh and the readout anode. The performance achieved with this detector is suited for applications in X-ray diffraction and synchrotron radiation. This detector has shown high reliability over time under harsh synchrotron radiation environment and robustness in manufacturing environment.

  18. ArDM: first results from underground commissioning

    CERN Document Server

    Badertscher, A; Bourgeois, N; Cantini, C; Curioni, A; Daniel, M; Degunda, U; Di Luise, S; Epprecht, L; Gendotti, A; Horikawa, S; Knecht, L; Lussi, D; Maire, G; Montes, B; Murphy, S; Natterer, G; Nikolics, K; Nguyen, K; Periale, L; Ravat, S; Resnati, F; Romero, L; Rubbia, A; Santorelli, R; Sergiampietri, F; Sgalaberna, D; Viant, T; Wu, S

    2013-01-01

    The Argon Dark Matter experiment is a ton-scale double phase argon Time Projection Chamber designed for direct Dark Matter searches. It combines the detection of scintillation light together with the ionisation charge in order to discriminate the background (electron recoils) from the WIMP signals (nuclear recoils). After a successful operation on surface at CERN, the detector was recently installed in the underground Laboratorio Subterr\\'aneo de Canfranc, and the commissioning phase is ongoing. We describe the status of the installation and present first results from data collected underground with the detector filled with gas argon at room temperature.

  19. Evaluating the Effect of Dental Filling Material and Filling Depth on the Strength and Deformation of Filled Teeth

    Directory of Open Access Journals (Sweden)

    Seifollah Gholampour

    2016-10-01

    Full Text Available ackground and aim: It is important to evaluate the effect of the type of filling material on deformation and strength of tooth after filling and also the effect of filling depth on quality of restoration of a decayed tooth. Material and Methods: The Orthopantomogram (OPG of the first and second molars of a 28-year-old man was made and the teeth were 3D modeled. The stress-deformation analysis was then performed on the models in the three states of normal tooth, tooth filled with amalgam and tooth filled with composite using finite element method under a distributed load of 400N equivalent to chewing force. Two values (1/2 and 1/3 of the tooth height were considered for filling depth in the analyses. Results: The results showed that the normal first molar was exposed to a 7.2% greater risk of dental injuries compared to the normal second molar and also a greater stress is created in it when it is filled with composite. The first molar filled with a composite material is 13.7% weaker than the normal tooth while it is almost as strong as a normal tooth when it is filled with amalgam. The effect of the type of filling material on the strength and deformation of the second molar was trivial. Conclusion: Amalgam is a more proper dental filling material for the first molar although a 16.7% change in drilling depth is needed for tooth preparation. Dental filling material and filling depth have a small effect on the strength and deformation of filled second molars.

  20. Influence of granularity on coal pyrolysis in Ar/H{sub 2} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Y.; Tian, Y.; Wang, D.; Xie, K.; Zhu, S. [Taiyuan University of Technology, Taiyuan (China). State Key Lab of C1 Chemistry and Technology, Shanxi key Lab of Coal Science and Technology

    2002-06-01

    Coal pyrolysis in arc plasma is very complex. These are many factors affecting this process, such as coal particle size, type of coal, proportion of working gases (Ar/H{sub 2}) and input powders. Coal pyrolysis in H{sub 2}-rich Ar plasma jet reactor was performed. The effect of granularity on coal conversion, acetylene yield, acetylene molar ratio in product gas and coke formation at the wall of reactor was studied. According to the coke formation mechanism in which the granularity is the key factor, the new way of coal feeding with double apex distribution granularity was put forward to eliminate the coke formation. 10 refs., 2 figs., 6 tabs.

  1. ArsP: a methylarsenite efflux permease.

    Science.gov (United States)

    Chen, Jian; Madegowda, Mahendra; Bhattacharjee, Hiranmoy; Rosen, Barry P

    2015-11-01

    Trivalent organoarsenic compounds are far more toxic than either pentavalent organoarsenicals or inorganic arsenite. Many microbes methylate inorganic arsenite (As(III)) to more toxic and carcinogenic methylarsenite (MAs(III)). Additionally, monosodium methylarsenate (MSMA or MAs(V)) has been used widely as an herbicide and is reduced by microbial communities to MAs(III). Roxarsone (3-nitro-4-hydroxybenzenearsonic acid) is a pentavalent aromatic arsenical that is used as antimicrobial growth promoter for poultry and swine, and its active form is the trivalent species Rox(III). A bacterial permease, ArsP, from Campylobacter jejuni, was recently shown to confer resistance to roxarsone. In this study, C. jejuni arsP was expressed in Escherichia coli and shown to confer resistance to MAs(III) and Rox(III) but not to inorganic As(III) or pentavalent organoarsenicals. Cells of E. coli expressing arsP did not accumulate trivalent organoarsenicals. Everted membrane vesicles from those cells accumulated MAs(III) > Rox(III) with energy supplied by NADH oxidation, reflecting efflux from cells. The vesicles did not transport As(III), MAs(V) or pentavalent roxarsone. Mutation or modification of the two conserved cysteine residues resulted in loss of transport activity, suggesting that they play a role in ArsP function. Thus, ArsP is the first identified efflux system specific for trivalent organoarsenicals.

  2. EFFECT OF Ar PRESSURE ON STRUCTURAL AND ELECTRICAL PROPERTIES OF Cu FILMS DEPOSITED ON GLASS BY DC MAGNETRON SPUTTERING

    Institute of Scientific and Technical Information of China (English)

    P.Wu; F.P.Wang; L.Q.Pan; Y.Tian; H.Qiu

    2002-01-01

    Cu films with thickness of 630-1300nm were deposited on glass substrates withoutheating by DC magnetron sputtering in pure Ar gas. Ar pressure was controlled to0.5, 1.0 and 1.5Pa respectively. The target voltage was fixed at 500V but the targetcurrent increased from 200 to 1150mA with Ar pressure increasing. X-ray diffrac-tion, scanning electron microscopy and atomic force microscopy were used to observethe structural characterization of the films. The resistivity of the films was measuredusing four-point probe technique. At all the Ar pressures, the Cu films have mixturecrystalline orientations of [111], [200] and [220] in the direction of the film growth.The film deposited at lower pressure shows more [111] orientation while that depositedat higher pressure has more [220] orientation. The amount of larger grains in the filmprepared at 0.5Pa Ar pressure is slightly less than that prepared at 1. 0Pa and 1.5PaAr pressures. The resistivities of the films prepared at three different Ar pressures rep-resent few differences, about 3-4 times of that of bulk material. Besides the depositionrate increases with Ar pressure because of the increase in target current. The contri-bution of the bombardment of energetic reflected Argon atoms to these phenomena isdiscussed.

  3. Determination of Ar Concentration Evolution Within DIII-D Core Plasma by X-ray Ross Filter Method

    Science.gov (United States)

    Bogatu, I. N.; Edgell, D. H.; Brooks, N. H.; Snider, R. T.; West, W. P.; Wade, M. R.

    2001-10-01

    Injection of the non-recycling noble gas Ar into the DIII-D divertor is a promising technique for reducing the heat load on the plates; it also seems to improve thermal transport in an advanced operating mode. During such experiments core plasma contamination by migrating Ar can be investigated by measuring the evolution of the Ar concentration profile using the Ross filter method implemented on the fan shaped X-ray poloidal diagnostics on DIII-D. A Ross filter with energy pass band centered on the ArXVII K_α line at 3.14 keV, discriminating Ar K_α line against background radiation, was used on DIII-D. A high sensitivity to the injected quantity of Ar and good discrimination against Ne was observed. We present reconstruction of Ar concentration profiles from the chord-integrated measurements using the measured Te and ne profiles. Using the transport code MIST, the impurity diffusion coefficients can be determined by matching the time evolution of the Ar concentration evolution.

  4. ArDroneXT - Ar.Drone 2 eXTension for swarming and service hosting

    OpenAIRE

    Autefage, Vincent; Chaumette, Serge

    2013-01-01

    This is an Operating System Setup Guide.; This report explains how to upgrade an Ar.Drone 2 for swarming and services hosting. In other words, it gives the technical information required to easily create a swarm of Ar.Drone 2 sharing a Wi-Fi network. Moreover, it describes the process to install new services and applications on the drone.

  5. A Refined Astronomically Calibrated 40Ar/39Ar Age for Fish Canyon Sanidine

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael; Zeeden, Christian

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision 40Ar/39Ar age for the Fish Canyon sanidine (FCs) neutron fluence...

  6. A refined astronomically calibrated 40Ar/39Ar age for Fish Canyon sanidine

    NARCIS (Netherlands)

    Rivera, T.A.; Storey, M.; Zeeden, C.; Hilgen, F.J.; Kuiper, K.

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision 40Ar/39Ar age for the FishCanyon sanidine (FCs) neutron fluence monitor,

  7. Modeling Augmented Reality User Interfaces with SSIML/AR

    Directory of Open Access Journals (Sweden)

    Arnd Vitzthum

    2006-06-01

    Full Text Available Augmented Reality (AR technologies open up new possibilities especially for task-focused domains such as assembly and maintenance. However, it can be noticed that there is still a lack of concepts and tools for a structured AR development process and an application specification above the code level. To address this problem we introduce SSIML/AR, a visual modeling language for the abstract specification of AR applications in general and AR user interfaces in particular. With SSIML/AR, three different aspects of AR user interfaces can be described: The user interface structure, the presentation of relevant information depending on the user’s current task and the integration of the user interface with other system components. Code skeletons can be generated automatically from SSIML/AR models. This enables the seamless transition from the design level to the implementation level. In addition, we sketch how SSIML/AR models can be integrated in an overall AR development process.

  8. AR-扩增实境

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    1、什么是AR-扩增实境?AR-扩增实境(Augmented Reality,简称AR),简单地说,就是把虚拟的物体和现实的场景进行嫁接。这是一种实时地计算摄影机影像的位置及角度并加上相应图像的技术,这种技术的目标是在屏幕上把虚拟世界套在现实世界并进行互动。

  9. 40Ar/39Ar and K/Ar dating of low grade metamorphism: examples on metabasites from Central Chile

    Science.gov (United States)

    Aguirre, L.; Feraud, G.; Fuentes, F.; Delbar, M.; Morata, D.

    2003-04-01

    Dating low to very low-grade burial metamorphic assemblages is often difficult because of (1) few mineral phases compositionally suitable to apply the 40Ar/39Ar and K-Ar methods, and (2) small amount in which these phases are commonly found. K-feldspar adularia, sericitic mica, and celadonite are the best known K-bearing secondary minerals. We present some successful attempts to analyse two distinct secondary phases from a same volcanic formation that allow to test the validity of the measured ages. These ages have been also compared with the crystallisation age of the volcanic rocks in which the secondary phases were lately developed. Adularia and sericite were selected from basic lava flows from a 3 to 13 km thick Cretaceous sequence from the Coastal Range of central Chile, at two different locations: the Bustamante Hill (west from Santiago), and the Cordón de Chacana, c. 80 km further north. Adularia came from a low-variance assemblage with pumpellyite, chlorite and low-albite contained in amygdules whereas sericite was present in milky-white strongly sericitized plagioclase crystals. While small clusters of rare fresh plagioclase grains from lava flows from Bustamante and Chacana displayed concordant plateau ages 119.4 ± 2.4 (2 sigma) and 118.7 ± 0.6 Ma, respectively, the adularia from the same formations gave sensibly younger ages around 94 Ma (high temperature steps), and 96.8 ± 0.2 Ma (plateau age) in Bustamante and Chacana, respectively. Sericite ages were measured in situ into single crystals of strongly transformed plagioclases. The relative proportion of sericite and plagioclase corresponding to each degasing step was monitored by measuring the Ca/K ratio (deduced from 37ArCa/39Ar_K). While intermediate ages were measured on some sericite of both sites (corresponding to a variable but permanent contribution of plagioclase on each step), a plateau age of 97.0 ± 1.6 Ma (concordant with adularia) could be obtained on a strongly sericitized plagioclase

  10. Subterranean production of neutrons, $^{39}$Ar and $^{21}$Ne: Rates and uncertainties

    CERN Document Server

    Šrámek, Ondřej; McDonough, William F; Mukhopadhyay, Sujoy; Peterson, R J

    2015-01-01

    Accurate understanding of the subsurface production of radionuclide $^{39}$Ar rate is necessary for argon dating techniques and noble gas geochemistry of the shallow and the deep Earth, and is also of interest to the WIMP dark matter experimental particle physics community. Our new calculations of subsurface production of neutrons, $^{21}$Ne, and $^{39}$Ar take advantage of the best available tools of nuclear physics to obtain reaction cross sections and spectra (TALYS) and to evaluate neutron propagation in rock (MCNP6). We discuss our method and results in relation to previous studies and show the relative importance of various neutron, $^{21}$Ne, and $^{39}$Ar nucleogenic production channels. Uncertainty in nuclear reaction cross sections, which is the major contributor to overall calculation uncertainty, is estimated from variability in existing experimental and library data. Depending on selected rock composition, on the order of $10^7$-$10^{10}$ {\\alpha} particles are produced in one kilogram of rock pe...

  11. The relationship between polyamines and hormones in the regulation of wheat grain filling.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available The grain weight of wheat is strongly influenced by filling. Polyamines (PA are involved in regulating plant growth. However, the effects of PA on wheat grain filling and its mechanism of action are unclear. The objective of the present study was to investigate the relationship between PAs and hormones in the regulation of wheat grain filling. Three PAs, spermidine (Spd, spermine (Spm, and putrescine (Put, were exogenously applied, and the grain filling characteristics and changes in endogenous PA and hormones, i.e., indole-3-acetic acid (IAA, zeatin (Z + zeatin riboside (ZR, abscisic acid (ABA, ethylene (ETH and gibberellin 1+4 (GAs, were quantified during wheat grain filling. Exogenous applications of Spd and Spm significantly increased the grain filling rate and weight, but exogenous Put had no significant effects on these measures. Exogenous Spd and Spm significantly increased the endogenous Spd, Spm, Z+ZR, ABA, and IAA contents and significantly decreased ETH evolution in grains. The endogenous Spd, Spm and Z+ZR contents were positively and significantly correlated with the grain filling rate and weight of wheat, and the endogenous ETH evolution was negatively and significantly correlated with the wheat grain filling rate and weight. Based upon these results, we concluded that PAs were involved in the balance of hormones that regulated the grain filling of wheat.

  12. Ionization satellites of the ArHe dimer

    Energy Technology Data Exchange (ETDEWEB)

    Miteva, Tsveta; Klaiman, Shachar; Gokhberg, Kirill [Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Gromov, Evgeniy V., E-mail: Evgeniy.Gromov@pci.uni-heidelberg.de [Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Laboratory of Quantum Chemistry, Computer Center, Irkutsk State University, K. Marks 1, 664003 Irkutsk (Russian Federation)

    2014-05-28

    Ionization satellites are key ingredients in the control of post ionization processes such as molecular dissociation and interatomic Coulombic decay. Here, using the high-level ab initio method of multi-reference configuration interaction up to triple excitations, we study the potential energy curves (PECs) of the ionization satellites of the ArHe dimer. With this model system, we demonstrate that the simple model used in alkaline earth metal and rare gas complexes to describe the satellites as a Rydberg electron moving on top of a dicationic core does not fully hold for the rare gas clusters. The more complex valence structure in the rare gas atom leads to the mixing of different electronic configurations of the dimer. This prevents one from assigning a single dicationic parent state to some of the ionization satellites. We further analyze the structure of the different PECs, demonstrating how the density of the Rydberg electron is reflected in the structure of the PEC wherever the simple model is applicable.

  13. Modification of stearic acid in Ar and Ar-O{sub 2} pulsed DC discharges

    Energy Technology Data Exchange (ETDEWEB)

    Bernardelli, E.A.; Souza, T.; Maliska, A.M.; Kleinjohann, K.J.; Bendo, T. [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil); Mafra, M. [Nancy-Universite (France). Institut Jean Lamour; CNRS, Nancy (France); Belmonte, T. [Federal University of Technology from Parana (UTFPR), Curitiba, PR (Brazil)

    2010-07-01

    Stearic acid (C{sub 1}8H{sub 36}O{sub 2}) was treated into Ar and Ar-O{sub 2}(10%) pulsed DC discharge created by a cathode-anode confined system. The samples were placed at the floating potential. The results show that the mass variation of the stearic acid samples after Ar-O{sub 2} plasma exposure is more important than the pure Ar plasma treatments. This comportment demonstrate that the oxygen actives species (O and O{sub 2} in all states) strongly enhance the etching process with regards to A{sup *} species, regardless of their concentration. After treatment by Ar and Ar-O{sub 2} plasma, analyses by X-ray diffraction show a significant structural modification of the samples surface, utilizing Ar-O{sub 2} plasma the modification was more pronounced. The chemical composition evolution shows that the acid function is etched preferentially in the beginning of the treatment (about 5 min) and that after 10 min the carbonic chains seems to be functionalized by oxygen. (author)

  14. Moving Beyond the Androgen Receptor (AR): Targeting AR-Interacting Proteins to Treat Prostate Cancer.

    Science.gov (United States)

    Foley, Christopher; Mitsiades, Nicholas

    2016-04-01

    Medical or surgical castration serves as the backbone of systemic therapy for advanced and metastatic prostate cancer, taking advantage of the importance of androgen signaling in this disease. Unfortunately, resistance to castration emerges almost universally. Despite the development and approval of new and more potent androgen synthesis inhibitors and androgen receptor (AR) antagonists, prostate cancers continue to develop resistance to these therapeutics, while often maintaining their dependence on the AR signaling axis. This highlights the need for innovative therapeutic approaches that aim to continue disrupting AR downstream signaling but are orthogonal to directly targeting the AR itself. In this review, we discuss the preclinical research that has been done, as well as clinical trials for prostate cancer, on inhibiting several important families of AR-interacting proteins, including chaperones (such as heat shock protein 90 (HSP90) and FKBP52), pioneer factors (including forkhead box protein A1 (FOXA1) and GATA-2), and AR transcriptional coregulators such as the p160 steroid receptor coactivators (SRCs) SRC-1, SRC-2, SRC-3, as well as lysine deacetylases (KDACs) and lysine acetyltransferases (KATs). Researching the effect of-and developing new therapeutic agents that target-the AR signaling axis is critical to advancing our understanding of prostate cancer biology, to continue to improve treatments for prostate cancer and for overcoming castration resistance.

  15. Ar-Ar Impact Heating Ages of Eucrites and Timing of the LHB

    Science.gov (United States)

    Bogard, Donald; Garrison, Daniel

    2009-01-01

    Eucrites and howardites, more than most meteorite types, show extensive impact resetting of their Ar-39-Ar-40 (K-Ar) ages approximately equal to 3.4-4.1 Ga ago, and many specimens show some disturbance of other radiometry chronometers as well. Bogard (1995) argued that this age resetting occurred on Vesta and was produced by the same general population of objects that produced many of the lunar impact basins. The exact nature of the lunar late heavy bombardment (LHB or 'cataclysm') remains controversial, but the timing is similar to the reset ages of eucrites. Neither the beginning nor ending time of the lunar LHB is well constrained. Comparison of Ar-Ar ages of brecciated eucrites with data for the lunar LHB can resolve both the origin of these impactors and the time period over which they were delivered to the inner solar system. This abstract reports some new Ar-Ar age data for eucrites, obtained since the authors' 1995 and 2003 papers.

  16. Ar-40/Ar-39 Ages of Maskelynite Grains from ALHA 77005

    Science.gov (United States)

    Turrin, B.; Park, J.; Herzog, G. F.; Lindsay, F. N.; Delaney, J. S.; Nyquist, L. E.; Swisher, C., III

    2013-01-01

    We present Ar-40/Ar-39 measurements for twelve small (20-60 micro-g) maskelynite samples from the heavily shocked martian meteorite ALHA 77005. The reported modal composition for ALHA 77005 is 50-60% olivine (Fa28), 30-40% pyroxene (Wo5Fs23En72), approx.8% maskelynite (An53), and approx.2% opaques by volume [1]). The meteorite is usually classified as a lherzolite. Previous Studies - Ar-40/Ar-39 results from previous work display disturbed release spectra [2,3]. In study [2], Ar-40/Ar-39 measurements on a 52-mg whole-rock sample produced an extremely disturbed release spec-trum, with all calculated apparent ages > 1 Ga, (Fig. 1). In a subsequent study [3], a light and a dark phase were analyzed. A 2.3-mg sample of the light, relatively low-K phase produced a disturbed release spectrum. For the first 20% of the Ar-39(sub K), most of the apparent ages exceeded >1 Ga; the remaining 80% yielded ages between 0.3-0.5 Ga. The integrated age for this phase is 0.9 Ga.

  17. Spectroscopic properties of alkali atoms embedded in Ar matrix.

    Science.gov (United States)

    Jacquet, E; Zanuttini, D; Douady, J; Giglio, E; Gervais, B

    2011-11-07

    We present a theoretical investigation of visible absorption and related luminescence of alkali atoms (Li, Na, and K) embedded in Ar matrix. We used a model based on core polarization pseudopotentials, which allows us to determine accurately the gas-to-matrix shifts of various trapping sites. The remarkable agreement between our calculated results and the experimental spectra recorded by several authors allows us to establish a clear assignment of the observed spectra, which are made of contributions from crystalline sites on the one hand, and of grain boundary sites on the other hand. Our study reveals remarkably large Stokes shifts, up to 9000 cm(-1), which could be observed experimentally to identify definitely the trapping sites.

  18. Investigation of Deep Ocean Circulation and Mixing Using Ar-39 (Invited)

    Science.gov (United States)

    Smethie, W. M.; Schlosser, P.

    2013-12-01

    Ar-39 is a radioactive noble gas that forms in the atmosphere by cosmic ray interaction with Ar-40. It has a half-life of 269 years and its production rate in the atmosphere has varied no more than 7% during the past 1000 years. It enters the surface ocean with an average equilibration time of about one month and thus the entire surface ocean, except for ice covered regions at high latitudes, is in quasi-equilibrium with the atmospheric Ar-39:Ar ratio. The well known input to the ocean, radioactive decay constant and chemical inertness make Ar-39 an ideal tracer of circulation and mixing in the deep ocean, where anthropogenic transient tracers such as CFCs and tritium have not yet penetrated. However, due to the difficult measurement, only about 125 oceanic Ar-39 samples have been measured to date. This was done by counting the decays of Ar-39 atoms and required a half liter of argon gas per sample, extracted from about 1500 liters of water. The 125 samples that have been measured provide a glimpse of the information that can be gained from Ar-39 observations. In the Pacific Ocean three vertical profiles show a decrease in Ar-39 from the surface mixed layer through the thermocline to a minimum at intermediate depths and an increase from there to the bottom. This reflects formation of bottom water around the Antarctic continent, spreading of this water northward and upwelling and mixing into intermediate depths. The lowest concentration was 6×4% modern which is equivalent to a 900-1600 year isolation time from the surface. In the Atlantic Ocean newly formed North Atlantic Deep Water has an Ar-39 concentration of about 85% modern compared to 55% modern for newly formed Antarctic Bottom Water and reach values as low as about 40% modern in the interior reflecting the more rapid ventilation of the deep Atlantic Ocean relative to the deep Pacific Ocean. In the Arctic Ocean the mean residence time of deep water in the Nansen, Amundsen and Makarov Basins based on Ar-39

  19. Evaluating the Effect of Dental Filling Material and Filling Depth on the Strength and Deformation of Filled Teeth

    OpenAIRE

    Seifollah Gholampour; Ghazale Zoorazma; Ehsan Shakouri

    2016-01-01

    ackground and aim: It is important to evaluate the effect of the type of filling material on deformation and strength of tooth after filling and also the effect of filling depth on quality of restoration of a decayed tooth. Material and Methods: The Orthopantomogram (OPG) of the first and second molars of a 28-year-old man was made and the teeth were 3D modeled. The stress-deformation analysis was then performed on the models in the three states of normal tooth, tooth filled with amalgam and ...

  20. Potassium Isotopic Compositions of NIST Potassium Standards and 40Ar/39Ar Mineral Standards

    Science.gov (United States)

    Morgan, Leah; Tappa, Mike; Ellam, Rob; Mark, Darren; Higgins, John; Simon, Justin I.

    2013-01-01

    Knowledge of the isotopic ratios of standards, spikes, and reference materials is fundamental to the accuracy of many geochronological methods. For example, the 238U/235U ratio relevant to U-Pb geochronology was recently re-determined [1] and shown to differ significantly from the previously accepted value employed during age determinations. These underlying values are fundamental to accurate age calculations in many isotopic systems, and uncertainty in these values can represent a significant (and often unrecognized) portion of the uncertainty budget for determined ages. The potassium isotopic composition of mineral standards, or neutron flux monitors, is a critical, but often overlooked component in the calculation of K-Ar and 40Ar/39Ar ages. It is currently assumed that all terrestrial materials have abundances indistinguishable from that of NIST SRM 985 [2]; this is apparently a reasonable assumption at the 0.25per mille level (1s) [3]. The 40Ar/39Ar method further relies on the assumption that standards and samples (including primary and secondary standards) have indistinguishable 40K/39K values. We will present data establishing the potassium isotopic compositions of NIST isotopic K SRM 985, elemental K SRM 999b, and 40Ar/39Ar biotite mineral standard GA1550 (sample MD-2). Stable isotopic compositions (41K/39K) were measured by the peak shoulder method with high resolution MC-ICP-MS (Thermo Scientific NEPTUNE Plus), using the accepted value of NIST isotopic SRM 985 [2] for fractionation [4] corrections [5]. 40K abundances were measured by TIMS (Thermo Scientific TRITON), using 41K/39K values from ICP-MS measurements (or, for SRM 985, values from [2]) for internal fractionation corrections. Collectively these data represent an important step towards a metrologically traceable calibration of 40K concentrations in primary 40Ar/39Ar mineral standards and improve uncertainties by ca. an order of magnitude in the potassium isotopic compositions of standards.

  1. "ARS 01", perspektiivide avamine / Helen Kivisoo

    Index Scriptorium Estoniae

    Kivisoo, Helen

    2001-01-01

    30. IX 2001-20. I 2002 Kiasmas kuuendat korda toimuvast rahvusvahelisest näitusest "ARS", kus Eestist osaleb Marko Mäetamm. Kuraatorid Tuula Arkio, Maaretta Jaukkuri, Patrik Nyberg, Jari-Pekka Vanhala. Teemaks "kolmas ruum". Näituse kajastamisest.

  2. User Interface Design for Military AR Applications

    Science.gov (United States)

    2010-12-12

    SI: AUGMENTED REALITY User interface design for military AR applications Mark A. Livingston • Zhuming Ai • Kevin Karsch • Gregory O. Gibson Received...several visual representations fundamental to SA. The UI M. A. Livingston (&) Z. Ai K. Karsch G. O. Gibson Naval Research Laboratory, Washington

  3. "Ars Dictaminis" and Modern Rhetorical Practice.

    Science.gov (United States)

    Sewell, Ernestine P.

    Although not all the problems of writing are solved by practice in letter writing, a review of the classical texts on "ars dictaminis"--letter writing--creates a strong argument for its increased use as an exercise in college composition classrooms. By incorporating the lessons of dictamen as a device for achieving rhetorical modes--narration,…

  4. 78 FR 9448 - Arkansas Disaster #AR-00061

    Science.gov (United States)

    2013-02-08

    ... ADMINISTRATION Arkansas Disaster AR-00061 AGENCY: U.S. Small Business Administration. ACTION: Notice SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for the... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  5. Effect of Ar bubbling during plasma electrolytic oxidation of AZ31B magnesium alloy in silicate electrolyte

    Science.gov (United States)

    Lee, Junghoon; Kim, Yonghwan; Chung, Wonsub

    2012-10-01

    Argon gas was bubbled during plasma electrolytic oxidation (PEO) treatment of magnesium alloy in a silicate solution. The appearance of arcs and plasma discharging was locally concentrated on the magnesium alloy surface and phase fraction of Mg2SiO4 in the oxide layer was increased due to Argon gas bubbling. The higher energy density of the Ar plasma atmosphere is believed to contribute to the effective formation of the high temperature phase (Mg2SiO4), particularly in the inner layer. Furthermore, the PEO treated Mg alloy with Ar bubbling showed improved corrosion resistance by a change of open pores structure.

  6. A comparative study of CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar plasmas for dry etching applications

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Inwoo [Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-Ro, Sejong 339-700 (Korea, Republic of); Efremov, Alexander [Department of Electronic Devices & Materials Technology, State University of Chemistry & Technology, 7F. Engels St., 153000 Ivanovo (Russian Federation); Yeom, Geun Young [Department of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kwon, Kwang-Ho, E-mail: kwonkh@korea.ac.kr [Department of Control and Instrumentation Engineering, Korea University, 2511 Sejong-Ro, Sejong 339-700 (Korea, Republic of)

    2015-03-31

    The effect of the O{sub 2}/Ar mixing ratio in CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar inductively coupled plasmas with a 50% fluorocarbon gas content on plasma parameters and active species densities, which influence dry etching mechanisms, was analyzed. The investigation combined plasma diagnostics using Langmuir probes and zero-dimensional plasma modeling. It was found that, in both gas systems, the substitution of Ar for O{sub 2} results in a similar change in the ion energy flux but causes the opposite behavior for the F atom flux. The mechanisms of these phenomena are discussed with regards to plasma chemistry. - Highlights: • The goal was to conduct a comparative study of CF{sub 4}/O{sub 2}/Ar and C{sub 4}F{sub 8}/O{sub 2}/Ar plasmas. • The focus was on the parameters directly influencing dry etching mechanisms. • Model-based analysis for neutral species was used in this paper.

  7. Discordant K-Ar and young exposure dates for the Windjana sandstone, Kimberley, Gale Crater, Mars

    Science.gov (United States)

    Vasconcelos, P. M.; Farley, K. A.; Malespin, C. A.; Mahaffy, P.; Ming, D.; McLennan, S. M.; Hurowitz, J. A.; Rice, Melissa S.

    2016-10-01

    K-Ar and noble gas surface exposure age measurements were carried out on the Windjana sandstone, Kimberley region, Gale Crater, Mars, by using the Sample Analysis at Mars instrument on the Curiosity rover. The sandstone is unusually rich in sanidine, as determined by CheMin X-ray diffraction, contributing to the high K2O concentration of 3.09 ± 0.20 wt % measured by Alpha-Particle X-ray Spectrometer analysis. A sandstone aliquot heated to 915°C yielded a K-Ar age of 627 ± 50 Ma. Reheating this aliquot yielded no additional Ar. A second aliquot heated in the same way yielded a much higher K-Ar age of 1710 ± 110 Ma. These data suggest incomplete Ar extraction from a rock with a K-Ar age older than 1710 Ma. Incomplete extraction at 900°C is not surprising for a rock with a large fraction of K carried by Ar-retentive K-feldspar. Likely, variability in the exact temperature achieved by the sample from run to run, uncertainties in sample mass estimation, and possible mineral fractionation during transport and storage prior to analysis may contribute to these discrepant data. Cosmic ray exposure ages from 3He and 21Ne in the two aliquots are minimum values given the possibility of incomplete extraction. However, the general similarity between the 3He (57 ± 49 and 18 ± 32 Ma, mean 30 Ma) and 21Ne (2 ± 32 and 83 ± 24 Ma, mean 54 Ma) exposure ages provides no evidence for underextraction. The implied erosion rate at the Kimberley location is similar to that reported at the nearby Yellowknife Bay outcrop.

  8. Growth of mica porphyroblasts under low-grade metamorphism - A Taiwanese case using in-situ40Ar/39Ar laser microprobe dating

    Science.gov (United States)

    Chen, Chih-Tung; Chan, Yu-Chang; Lo, Ching-Hua; Lu, Chia-Yu

    2016-11-01

    Mica porphyroblasts, a common metamorphic microstructure, are analyzed in the slate belt of northern Taiwan where large fish-like growths are found within a meta-pyroclastics. With constraints on the time-temperature history from deposition through peak metamorphic state to exhumation, in-situ40Ar/39Ar laser microprobe dating was carried out on muscovite and corrensite fibers of mm-scale mica porphyroblasts grown on a pressure-solution seam. Because the peak metamorphic temperature and the porphyroblast formation condition (∼250 °C) remained far below the closure temperature of the K-Ar radioisotope system in muscovite, and the absence of muscovite in the mafic protolith, the dating results likely document the growth of the mica porphyroblast fabrics. The syn-kinematic nature of the analyzed porphyroblasts is confirmed by the ∼6 to ∼2.5 Ma growth ages, suggesting that the host rock was continuously deformed during the earlier two-thirds of the Taiwan Orogeny. The pattern of fiber growth, in contrast to outward-decreasing ages normally observed in peripheral recrystallization, appears random and resembles void fills in boudin openings. We postulate that syntaxial crack-seal following tensile micro-boudinage, along with slips on sub-grain boundaries, as a viable mechanism for the development of mica porphyroblasts and fish especially in lower-grade metamorphic rocks.

  9. Negative ion gas-phase chemistry of arenes.

    Science.gov (United States)

    Danikiewicz, Witold; Zimnicka, Magdalena

    2016-01-01

    Reactions of aromatic and heteroaromatic compounds involving anions are of great importance in organic synthesis. Some of these reactions have been studied in the gas phase and are occasionally mentioned in reviews devoted to gas-phase negative ion chemistry, but no reviews exist that collect all existing information about these reactions. This work is intended to fill this gap. In the first part of this review, methods for generating arene anions in the gas phase and studying their physicochemical properties and fragmentation reactions are presented. The main topics in this part are as follows: processes in which gas-phase arene anions are formed, measurements and calculations of the proton affinities of arene anions, proton exchange reactions, and fragmentation processes of substituted arene anions, especially phenide ions. The second part is devoted to gas-phase reactions of arene anions. The most important of these are reactions with electrophiles such as carbonyl compounds and α,β-unsaturated carbonyl and related compounds (Michael acceptors). Other reactions including oxidation of arene anions and halogenophilic reactions are also presented. In the last part of the review, reactions of electrophilic arenes with nucleophiles are discussed. The best known of these is the aromatic nucleophilic substitution (SN Ar) reaction; however, other processes that lead to the substitution of a hydrogen atom in the aromatic ring are also very important. Aromatic substrates in these reactions are usually but not always nitroarenes bearing other substituents in the ring. The first step in these reactions is the formation of an anionic σ-adduct, which, depending on the substituents in the aromatic ring and the structure of the attacking nucleophile, is either an intermediate or a transition state in the reaction path. In the present review, we attempted to collect the results of both experimental and computational studies of the aforementioned reactions conducted since the

  10. Theoretical prediction on vibrational spectra of [Ar…Ar-H]+

    Institute of Scientific and Technical Information of China (English)

    LI; Wei(李巍); ZHAO; Xinsheng(赵新生)

    2003-01-01

    Centrosymmetric linear [Ar-H-Ar]+ and asymmetric linear [Ar…Ar-H]+ are two stable configurations of [Ar2H]+. Based on the global potential energy surface of [Ar2H]+ provided by our group recently, we calculated the vibrational spectra of [Ar…Ar-H]+ with total angular momentum J = 0 by time-dependent quantum mechanical method, and the influence of quantum tunneling effect on vibrational spectra was found. With the help of the observation on the eigenstate functions and the modified potential energy surface, assignments were made to the spectra. The strong coupling between the excited bending mode of [Ar-H-Ar]+ and the vibrational states of [Ar…Ar-H]+ was discussed.

  11. Dedicated composite fillings − inlays

    Directory of Open Access Journals (Sweden)

    Šaulić Slobodan

    2003-01-01

    Full Text Available Background. The aim of the study was to evaluate the quality and persistance of esthetics of dedicated inlay by clinical methods. Methods. The paper reviews the clinical significance and technique of preparing particular composite inlays before and after the construction of the metallic framework partial denture. On the basis of indications the total of 30 inlays were placed into cavities under relatively dry working conditions. Six, twelve eighteen and twenty-four months after the placement of filling, control check-up was carried out by Ryge criteria. Results. After two years marginal discoloration as well as the change of the colour occured in 3.3% of inlays. There was neither detectable secondary caries, nor the symtoms of pulpal damage. The requirements to be fulfilled concerning the composite materials in order that they can be implemented for this purpose, were also discussed. Conclusion. From the clinical point of view, purpouse inlays from Herculite XRV lab C8B in combination with Opti Bond System and composite cement Porcelite Dual Cure showed high functional and esthetic values in the observational period of two years.

  12. Metalloregulatory properties of the ArsD repressor.

    Science.gov (United States)

    Chen, Y; Rosen, B P

    1997-05-30

    The plasmid-encoded arsenical resistance (ars) operon of plasmid R773 produces resistance to trivalent and pentavalent salts of the metalloids arsenic and antimony in cells of Escherichia coli. The first two genes in the operon, arsR and arsD, were previously shown to encode trans-acting repressor proteins. ArsR controls the basal level of expression of the operon, while ArsD controls maximal expression. Thus, action of the two repressors form a homeostatic regulatory circuit that maintains the level of ars expression within a narrow range. In this study, we demonstrate that ArsD binds to the same site on the ars promoter element as ArsR but with 2 orders of magnitude lower affinity. The results of gel shift assays demonstrate that ArsD is released from the ars DNA promoter by phenylarsine oxide, sodium arsenite, and potassium antimonyl tartrate (in order of effectiveness), the same inducers to which ArsR responds. Using the quenching of intrinsic tryptophan fluorescence to measure the affinity of the repressor for inducers, apparent Kd values for Sb(III) and As(III) of 2 and 60 microM, respectively, were obtained. These results demonstrate that the arsR-arsD pair provide a sensitive mechanism for sensing a wide range of environmental heavy metals.

  13. A study on plasma parameters in Ar/SF6 inductively coupled plasma

    Science.gov (United States)

    Oh, Seung-Ju; Lee, Hyo-Chang; Chung, Chin-Wook

    2017-01-01

    Sulfur hexafluoride (SF6) gas or Ar/SF6 mixing gas is widely used in plasma processes. However, there are a little experimental studies with various external parameters such as gas pressure and mixing ratio. In this work, a study of the plasma parameters by changing the gas mixing ratio was done in an Ar/SF6 inductively coupled plasma from the measurement of the electron energy distribution function. At a low gas pressure, as the mixing ratio of SF6 gas increased at a fixed inductively coupled plasma (ICP) power, the electron density decreased and the electron temperature increased, while they were not changed drastically. At a high gas pressure, a remarkable increase in the electron temperature was observed with the decrease in the electron density. These variations are due to the electron loss reactions such as the electron attachment. It was also found that at a fixed ICP power, the negative ion creation with the diluted SF6 gas can change the discharge mode transition from an inductive mode to a capacitive mode at the high gas pressure. The electron attachment reactions remove the low energy electrons and change the mean electron energy towards higher energies with diluting SF6 gas at high pressure. The measured results were compared with the simplified global model, and the global model is in relatively good agreement with the measured plasma parameters except for the result in the case of the large portion of SF6 gas at the high pressure and the capacitive mode, which causes strong negative ion formation by the electron attachment reactions.

  14. Rotational excitation of 36ArH+ by He at low temperature

    Science.gov (United States)

    Bop, Cheikh T.; Hammami, K.; Niane, A.; Faye, N. A. B.; Jaïdane, N.

    2017-02-01

    In this paper, we focus on the determination of the rotational excitation rate coefficients of the first observed molecule containing noble gas 36ArH+ isotope by He. Hence, we present the first potential energy surface (PES) of ArH+ -He van der Waals system. The interaction PES of the ArH+(X1Σ+)-He(1S) complex is calculated by the ab initio explicitly correlated coupled cluster with single, double, and perturbative triple excitation (CCSD(T)-F12) method in connection with the augmented correlation consistent triple zeta Gaussian basis (aug-cc-pVTZ). The interaction potential presents two global minima of 708.00 and 172.98 cm-1 below the ArH+(X1Σ+)-He(1S) dissociation limit. Using the PES obtained, we have computed integral inelastic cross-sections in the close-coupling approach among the first 11 rotational levels of ArH+ for energies up to 2500 cm-1. Downward rate coefficients were determined at low temperature (T ≤ 300 K). It is expected that the data worked out in this study may be beneficial for further astrophysical investigations as well as laboratory experiments.

  15. Surfaces that become isotopic after Dehn filling

    CERN Document Server

    Bachman, David; Sedgwick, Eric

    2010-01-01

    We show that after generic filling along a torus boundary component of a 3-manifold, no two closed, 2-sided, essential surfaces become isotopic, and no closed, 2-sided, essential surface becomes inessential. That is, the set of essential surfaces (considered up to isotopy) survives unchanged in all suitably generic Dehn fillings. Furthermore, for all but finitely many non-generic fillings, we show that two essential surfaces can only become isotopic in a constrained way.

  16. Construction of a chimeric ArsA-ArsB protein for overexpression of the oxyanion-translocating ATPase.

    Science.gov (United States)

    Dou, D; Owolabi, J B; Dey, S; Rosen, B P

    1992-12-25

    Resistance to toxic oxyanions of arsenic and antimony in Escherichia coli is conferred by the conjugative R-factor R773, which encodes an ATP-driven anion extrusion pump. The ars operon is composed of three structural genes, arsA, arsB, and arsC. Although transcribed as a single unit, the three genes are differentially expressed as a result of translational differences, such that the ArsA and ArsC proteins are produced in high amounts relative to the amount of ArsB protein made. Consequently, biochemical characterization of the ArsB protein, which is an integral membrane protein containing the anion-conducting pathway, has been limited, precluding studies of the mechanism of this oxyanion pump. To overexpress the arsB gene, a series of changes were made. First, the second codon, an infrequently used leucine codon, was changed to a more frequently utilized codon. Second, a GC-rich stem-loop (delta G = -17 kcal/mol) between the third and twelfth codons was destabilized by changing several of the bases of the base-paired region. Third, the re-engineered arsB gene was fused 3' in frame to the first 1458 base pairs of the arsA gene to encode a 914-residue chimeric protein (486 residues of the ArsA protein plus 428 residues of the mutated ArsB protein) containing the entire re-engineered ArsB sequence except for the initiating methionine. The ArsA-ArsB chimera has been overexpressed at approximately 15-20% of the total membrane proteins. Cells producing the chimeric ArsA-ArsB protein with an arsA gene in trans excluded 73AsO2- from cells, demonstrating that the chimera can function as a component of the oxyanion-translocating ATPase.

  17. Theoretical analysis of ion kinetic energies and DLC film deposition by CH4+Ar (He) dielectric barrier discharge plasmas

    Institute of Scientific and Technical Information of China (English)

    Liu Yan-Hong; Zhang Jia-Liang; Ma Teng-Cai; Li Jian; Liu Dong-Ping

    2007-01-01

    The kinetic energy of ions in dielectric barrier discharge plasmas are analysed theoretically using the model of binary collisions between ions and gas molecules. Langevin equation for ions in other gases, Blanc law for ions in mixed gases, and the two-temperature model for ions at higher reduced field are used to determine the ion mobility. The kinetic energies of ions in CH4 + Ar(He) dielectric barrier discharge plasma at a fixed total gas pressure and various Ar (He)concentrations are calculated. It is found that with increasing Ar (He) concentration in CH4 + Ar (He) from 20% to 83%,the CH4+ kinetic energy increases from 69.6 (43.9) to 92.1 (128.5)eV, while the Ar+ (He+) kinetic energy decreases from 97 (145.2) to 78.8 (75.5)eV. The increase of CH4+ kinetic energy is responsible for the increase of hardness of diamond-like carbon films deposited by CH4 + Ar (He) dielectric barrier discharge without bias voltage over substrates.

  18. Absorption spectra of e-beam-excited Ne, Ar, and Kr, pure and in binary mixtures.

    Science.gov (United States)

    Levchenko, A O; Ustinovskii, N N; Zvorykin, V D

    2010-10-21

    A technique using the broadband emission of a laser plume as probe radiation is applied to record UV-visible (190-510 nm) absorption spectra of Ne, Ar, and Kr, pure and in binary mixtures under moderate e-beam excitation up to 1 MW/cm(3). In all the rare gases and mixtures, the absorption spectra show continuum related to Rg(2) (+) homonuclear ions [peaking at λ∼285, 295, and 320 nm in Ne, Ar, and Kr(Ar/Kr), respectively] and a number of atomic lines related mainly to Rg(∗)(ms) levels, where m is the lowest principal quantum number of the valence electron. In argon, a continuum related to Ar(2) (∗) (λ∼325 nm) is also recorded. There are also trains of narrow bands corresponding to Rg(2) (∗)(npπ (3)Π(g))←Rg(2) (∗)(msσ (3)Σ(u) (+)) transitions. All the spectral features mentioned above were reported in literature but have never been observed simultaneously. Although charge transfer to a homonuclear ion of the heavier additive is commonly believed to dominate in binary rare-gas mixtures, it is found in this study that in Ne/Kr mixture, the charge is finally transferred from the buffer gas Ne(2) (+) ion not to Kr(2) (+) but to heteronuclear NeKr(+) ion.

  19. First results from Tyrex, the new polarized-{sup 3}He filling station at ILL

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, K.H. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France)]. E-mail: andersen@ill.fr; Chung, R. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Guillard, V. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Humblot, H. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Jullien, D. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Lelievre-Berna, E. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Petoukhov, A. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France); Tasset, F. [Institut Laue-Langevin, 6, rue J. Horowitz, F-38042 Grenoble Cedex 9 (France)

    2005-02-15

    A new filling station for nuclear polarisation of {sup 3}He gas has been constructed at the ILL, Grenoble. The 'Tyrex' machine uses metastability-exchange optical pumping for polarising the {sup 3}He gas at about 1 mbar pressure. The gas is then compressed up to several bars via a hydraulic titanium-alloy piston compressor. The machine can provide about 1.5 bar-l/h of polarised gas--an order-of-magnitude increase over the first filling station installed at the ILL in 1996. The compressed, polarised gas is used for polarising neutron beams for condensed-matter and fundamental physics experiments. First results are presented and examples of implementations on existing neutron instruments at ILL are described.

  20. Recoil ion charge state distributions in low energy Ar{sup q+} {minus} Ar collisions

    Energy Technology Data Exchange (ETDEWEB)

    Vancura, J.; Marchetti, V.; Kostroun, V.O.

    1992-12-31

    We have measured the recoil ion charge state distributions in Ar{sup q+} -- Ar (8{le}q{le}16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar{sup 8-16+}, recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar{sup 10-16+}, there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy.

  1. The effects of retrograde reactions and of diffusion on 39Ar-40Ar ages of micas

    DEFF Research Database (Denmark)

    Allaz, Julien; Engi, Martin; Berger, Alfons

    2011-01-01

    Effects of metamorphic reactions occurring during decompression were explored to understand their influence on 39Ar-40Ar ages of micas. Monometamorphic metasediments from the Lepontine Alps (Switzerland) were studied. Collected samples reached lower amphibolite facies during the Barrovian....../K and Cl/K ratios) did not change and the resulting ages can be interpreted unambiguously. In mineral separates containing two white micas, Ca/K and Cl/K ratios were variable, reflecting non-simultaneous laboratory degassing of the two heterochemical Ar-reservoirs. These ratios were used to identify each...... Ar reservoir and to unravel the age. In a chlorite-margarite-biotite-calcschist equilibrated near 560 °C and 0.65 GPa, biotite, margarite, and muscovite all yield ages around 18 Ma. At slightly higher grade (560-580 °C, 0.8-0.9 GPa), the assemblage muscovite-paragonite-plagioclase is at equilibrium...

  2. Melt-inclusion-hosted excess 40Ar in quartz crystals of the Bishop and Bandelier magma systems

    Science.gov (United States)

    Winick, J.A.; McIntosh, W.C.; Dunbar, N.W.

    2001-01-01

    40Ar/39Ar experiments on melt-inclusion-bearing quartz (MIBQ) from the Bishop and Bandelier Tuff Plinian deposits indicate high concentrations of excess 40Ar in melt inclusions. Two rhyolite glass melt inclusion populations are present in quartz; exposed melt inclusions and trapped melt inclusions. Air-abrasion mill grinding and hydrofluoric acid treatments progressively remove exposed melt inclusions while leaving trapped melt inclusions unaffected. Laser step-heating of MIBQ yields increasing apparent ages as a function of exposed melt inclusion removal, reflecting the higher nonatmospheric 40Ar concentrations hosted in trapped melt inclusions. Exposed melt inclusion-free MIBQ from the Bishop, Upper Bandelier, and Lower Bandelier Tufts yield total-gas ages of 3.70 ?? 1.00 Ma, 11.54 ?? 0.87 Ma, and 14.60 ?? 1.50 Ma, respectively. We interpret these old apparent ages as compelling evidence for the presence of excess 40Ar in MIBQ. Trapped melt inclusions in sanidine phenocrysts may contain excess 40Ar concentrations similar to those in MIBQ. This excess 40Ar has the potential to increase single-crystal laser-fusion ages of sanidine by tens of thousands of years, relative to the actual eruption age.

  3. Electrical and optical properties of Ar/NH3 atmospheric pressure plasma jet

    Science.gov (United States)

    Chang, Zheng-Shi; Yao, Cong-Wei; Chen, Si-Le; Zhang, Guan-Jun

    2016-09-01

    Inspired by the Penning effect, we obtain a glow-like plasma jet by mixing ammonia (NH3) into argon (Ar) gas under atmospheric pressure. The basic electrical and optical properties of an atmospheric pressure plasma jet (APPJ) are investigated. It can be seen that the discharge mode transforms from filamentary to glow-like when a little ammonia is added into the pure argon. The electrical and optical analyses contribute to the explanation of this phenomenon. The discharge mode, power, and current density are analyzed to understand the electrical behavior of the APPJ. Meanwhile, the discharge images, APPJ's length, and the components of plasma are also obtained to express its optical characteristics. Finally, we diagnose several parameters, such as gas temperature, electron temperature, and density, as well as the density number of metastable argon atoms of Ar/NH3 APPJ to help judge the usability in its applications.

  4. Soil Fills Phoenix Laboratory Cell

    Science.gov (United States)

    2008-01-01

    This image shows four of the eight cells in the Thermal and Evolved-Gas Analyzer, or TEGA, on NASA's Phoenix Mars Lander. TEGA's ovens, located underneath the cells, heat soil samples so the released gases can be analyzed. Left to right, the cells are numbered 7, 6, 5 and 4. Phoenix's Robotic Arm delivered soil most recently to cell 6 on the 137th Martian day, or sol, of the mission (Oct. 13, 2008). Phoenix's Robotic Arm Camera took this image at 3:03 p.m. local solar time on Sol 138 (Oct. 14, 2008). Phoenix landed on Mars' northern plains on May 25, 2008. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  5. Selective filling of Photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Noordegraaf, Danny; Sørensen, Thorkild

    2005-01-01

    A model for calculating the time necessary for filling one or more specific holes in a photonic crystal fibre is made. This model is verified for water, and its enabling potential is illustrated by a polymer application. Selective filling of the core in an air-guide photonic crystal fibre is demo...

  6. Influence of template fill in graphoepitaxy DSA

    Science.gov (United States)

    Doise, Jan; Bekaert, Joost; Chan, Boon Teik; Hong, SungEun; Lin, Guanyang; Gronheid, Roel

    2016-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) is considered a promising patterning approach for the 7 nm node and beyond. Specifically, a grapho-epitaxy process using a cylindrical phase BCP may offer an efficient solution for patterning randomly distributed contact holes with sub-resolution pitches, such as found in via and cut mask levels. In any grapho-epitaxy process, the pattern density impacts the template fill (local BCP thickness inside the template) and may cause defects due to respectively over- or underfilling of the template. In order to tackle this issue thoroughly, the parameters that determine template fill and the influence of template fill on the resulting pattern should be investigated. In this work, using three process flow variations (with different template surface energy), template fill is experimentally characterized as a function of pattern density and film thickness. The impact of these parameters on template fill is highly dependent on the process flow, and thus pre-pattern surface energy. Template fill has a considerable effect on the pattern transfer of the DSA contact holes into the underlying layer. Higher fill levels give rise to smaller contact holes and worse critical dimension uniformity. These results are important towards DSA-aware design and show that fill is a crucial parameter in grapho-epitaxy DSA.

  7. Continuous-wave high specific output power Ar-He-Xe laser with transverse RF excitation

    NARCIS (Netherlands)

    Udalov, Yu.B.; Peters, P.J.M.; Heeman-Ilieva, M.B.; Witteman, W.J.; Ochkin, V.N.

    1994-01-01

    A transverse RF excited gas discharge has been successfully used to produce a CW Ar-He-Xe laser. A maximum output power of 330 mW has been obtained from an experimental device with 37 cm active length and a 2.25 (DOT) 2.25 cm2 cross-section. This corresponds to a specific output power of about 175 m

  8. 40Ar* loss in experimentally deformed muscovite and biotite with implications for 40Ar/39Ar geochronology of naturally deformed rocks

    Science.gov (United States)

    Cosca, M.; Stunitz, H.; Bourgeix, A.-L.; Lee, J.P.

    2011-01-01

    The effects of deformation on radiogenic argon (40Ar*) retentivity in mica are described from high pressure experiments performed on rock samples of peraluminous granite containing euhedral muscovite and biotite. Cylindrical cores, ???15mm in length and 6.25mm in diameter, were drilled from granite collected from the South Armorican Massif in northwestern France, loaded into gold capsules, and weld-sealed in the presence of excess water. The samples were deformed at a pressure of 10kb and a temperature of 600??C over a period 29 of hours within a solid medium assembly in a Griggs-type triaxial hydraulic deformation apparatus. Overall shortening in the experiments was approximately 10%. Transmitted light and secondary and backscattered electron imaging of the deformed granite samples reveals evidence of induced defects and for significant physical grain size reduction by kinking, cracking, and grain segmentation of the micas.Infrared (IR) laser (CO2) heating of individual 1.5-2.5mm diameter grains of muscovite and biotite separated from the undeformed granite yield well-defined 40Ar/39Ar plateau ages of 311??2Ma (2??). Identical experiments on single grains separated from the experimentally deformed granite yield results indicating 40Ar* loss of 0-35% in muscovite and 2-3% 40Ar* loss in biotite. Intragrain in situ ultraviolet (UV) laser ablation 40Ar/39Ar ages (??4-10%, 1??) of deformed muscovites range from 309??13 to 264??7Ma, consistent with 0-16% 40Ar* loss relative to the undeformed muscovite. The in situ UV laser ablation 40Ar/39Ar ages of deformed biotite vary from 301 to 217Ma, consistent with up to 32% 40Ar* loss. No spatial correlation is observed between in situ 40Ar/39Ar age and position within individual grains. Using available argon diffusion data for muscovite the observed 40Ar* loss in the experimentally treated muscovite can be utilized to predict average 40Ar* diffusion dimensions. Maximum 40Ar/39Ar ages obtained by UV laser ablation overlap those

  9. Space-filling curves of self-similar sets (I): iterated function systems with order structures

    Science.gov (United States)

    Rao, Hui; Zhang, Shu-Qin

    2016-07-01

    This paper is the first part of a series which provides a systematic treatment of the space-filling curves of self-similar sets. In the present paper, we introduce a notion of linear graph-directed IFS (linear GIFS in short). We show that to construct a space-filling curve of a self-similar set, it amounts to exploring its linear GIFS structures. Compared to the previous methods, such as the L-system or recurrent set method, the linear GIFS approach is simpler, more rigorous and leads to further studies on this topic. We also propose a new algorithm for the beautiful visualization of space-filling curves. In a series of papers Dai et al (2015 arXiv:1511.05411 [math.GN]), Rao and Zhang (2015) and Rao and Zhang (2015), we investigate for a given self-similar set how to get ‘substitution rules’ for constructing space-filling curves, which was obscure in the literature. We solve the problem for self-similar sets of finite type, which covers most of the known results on constructions of space-filling curves.

  10. micro strip gas chamber

    CERN Multimedia

    1998-01-01

    About 16 000 Micro Strip Gas Chambers like this one will be used in the CMS tracking detector. They will measure the tracks of charged particles to a hundredth of a millimetre precision in the region near the collision point where the density of particles is very high. Each chamber is filled with a gas mixture of argon and dimethyl ether. Charged particles passing through ionise the gas, knocking out electrons which are collected on the aluminium strips visible under the microscope. Such detectors are being used in radiography. They give higher resolution imaging and reduce the required dose of radiation.

  11. The polystyrene microsphere filling with hydrogen isotopes through the fill tube with consequent freezing

    Science.gov (United States)

    Izgorodin, V. M.; Solomatina, E. Y.; Pepelyaev, A. P.; Rogozhina, M. A.; Osetrov, E. I.

    2016-09-01

    Process of spherical polystyrene capsules filling with hydrogen isotopes through the fill tube for the purpose of a cryogenic target building is described. The scheme of the stand for researches and a technique of carrying out of experiments is represented. Results of capsules filling and subsequent freezing for protium, deuterium and protium- deuterium mixture are shown.

  12. Enseñar un oficio, proponer una forma

    OpenAIRE

    Vitale, Daniele

    2015-01-01

    El oficio de enseñar. Enseñar a través de la técnica, enseñar por vía de la cultura. Una ciudadela de figuras. Imitación y relación personal. Enseñar a partir de un sistema. Partir del inicio. Posponer la realidad Peer Reviewed

  13. On concentration of $^{42}$Ar in the Earth's atmosphere

    CERN Document Server

    Barabash, A S

    2016-01-01

    Data from the DBA liquid argon ionization chamber experiment have been used to obtain an estimate on the concentration of $^{42}$Ar in the Earth's atmosphere, $6.8^{+1.7}_{-3.2}\\cdot10^{-21}$ atoms of $^{42}$Ar per atom of $^{40}$Ar corresponding to the $^{42}$Ar activity of $1.2^{+0.3}_{-0.5}$ $\\mu$Bq per cubic meter of air.

  14. On concentration of 42Ar in the Earth's atmosphere

    Science.gov (United States)

    Barabash, A. S.; Saakyan, R. R.; Umatov, V. I.

    2016-12-01

    Data from the DBA liquid argon ionization chamber experiment have been used to obtain an estimate on the concentration of 42Ar in the Earth's atmosphere, 6 .8-3.2+1.7 ·10-21 atoms of 42Ar per atom of 40Ar corresponding to the 42Ar activity of 1 .2-0.5+0.3 μBq per cubic meter of air.

  15. Phase behavior of mixed Ar-Kr, Ar-Xe and Kr-Xe monolayer films on graphite: a Monte Carlo study.

    Science.gov (United States)

    Patrykiejew, A

    2013-01-01

    Using Monte Carlo simulation methods in the grand canonical ensemble we have studied the behavior of mixed Ar-Kr, Ar-Xe and Kr-Xe monolayer films on the graphite basal plane. We have considered the adsorption of the lighter component, either argon or krypton, under the condition of a fixed chemical potential of the heavier component (krypton or xenon), as well as on the graphite surface with preadsorbed small amounts of a heavier noble gas. In both types of simulation the composition of the adsorbed layer is not conserved. We discuss the phase behavior of mixed films emerging from both types of 'computer experiment'. We also demonstrate that Monte Carlo simulation allows us to estimate the effects of preadsorbed xenon on the commensurate-incommensurate transition in the krypton monolayer film and gives the results that are in good quantitative agreement with experimental data.

  16. Growth Rate Estimates of Supergene Manganese Nodule by 40Ar/39Ar Isotopic Dating

    Institute of Scientific and Technical Information of China (English)

    Li Jianwei; Vasconcelos P M

    2004-01-01

    Increasing world-class, high-grade, and metals-enriched supergene manganese ore deposits have been discovered in the last two decades, making them more and more economically important. However, data on the timing and duration of their formation are sparse, mainly due to the difficulties extracting datable minerals suited to traditional radiometric dating methods. Hollandite, cryptomelane, coronadite, todorokite, and manjiroite are common manganese oxide minerals in supergene environments. These minerals host potassium of variable amounts from 0.1 wt% to 5.0 wt% in their structural sites. This geochemical property provides possibility to date supergene manganese ores by using K-Ar and 40Ar/39Ar methods. In this study, we perform 40Ar/39Ar dating on a 7.1-cm-thick botryoidal manganese nodule from an ancient weathering profile at Mount Tabor, central Queensland, Australia. Laser microprobe incremental analyses of distinct growth bands, from the inner core through the intermediate bands to the outermost crusts of the nodule, have yielded high quality 40Ar/39Ar ages at 27.3 Ma, 20.9 Ma, 19.2 Ma, and 16.1 Ma, respectively. The age results permit preliminary estimates on the average growth rates of the nodule varying from 4.7×10-3 mm/ka to 7.6×10-3 mm/ka to 9.0×10-3 mm/ka, from the core to the rim. Results of this study are of significance in our understanding of the mode, mechanism, process, and climatic conditions in the formation of supergene manganese ore deposits.

  17. Regulation of AR Degradation and Function by Ubiquitylation

    Science.gov (United States)

    2015-10-01

    STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The pathways that normally mediate AR...ligase (CHIP) may mediate the polyubiquitylation and proteasome degradation of AR that fails to fold appropriately and bind ligand. However, there are...pathways that normally mediate the ubiquitin dependent or independent degradation of AR, which might be targeted therapeutically, remain to be

  18. Discrete self similarity in filled type I strong explosions

    Science.gov (United States)

    Yalinewich, Almog; Sari, Re'em

    2013-12-01

    We present new solutions to the strong explosion problem in a non power law density profile. The unperturbed self similar solutions developed by Sedov, Taylor, and Von Neumann describe strong Newtonian shocks propagating into a cold gas with a density profile falling off as r-ω, where ω le 7-γ /γ +1 (filled type I solutions), and γ is the adiabatic index of the gas. The perturbations we consider are spherically symmetric and log periodic with respect to the radius. While the unperturbed solutions are continuously self similar, the log periodicity of the density perturbations leads to a discrete self similarity of the perturbations, i.e., the solution repeats itself up to a scaling at discrete time intervals. We discuss these solutions and verify them against numerical integrations of the time dependent hydrodynamic equations. This is an extension of a previous investigation on type II solutions and helps clarifying boundary conditions for perturbations to type I self similar solutions.

  19. Antarlides: A New Type of Androgen Receptor (AR) Antagonist that Overcomes Resistance to AR-Targeted Therapy.

    Science.gov (United States)

    Saito, Shun; Fujimaki, Takahiro; Panbangred, Watanalai; Igarashi, Yasuhiro; Imoto, Masaya

    2016-02-18

    Prostate cancer is treated with androgen receptor (AR) antagonists but most patients experience disease progression after long-term treatment with these compounds. Therefore, new AR antagonists are required for patient follow-up treatment. In the course of screening for a new AR antagonist, we isolated the novel compounds antarlides A-E (1-5) from Streptomyces sp. BB47. Antarlides are mutually isomeric with respect to the double bond and have a 22-membered-ring macrocyclic structure. The full stereostructure of 1 was established by chemical modifications, including methanolysis, the Trost method, acetonide formation, and the PGME method. 1-5 inhibited the binding of androgen to ARs in vitro. In addition, 2 inhibited the transcriptional activity of not only wild-type AR but also mutant ARs, which are seen in patients with acquired resistance to clinically used AR antagonists. Therefore, antarlides are a potent new generation of AR antagonists that overcome resistance.

  20. Droplet Measurement below Single-Layer Grid Fill

    Directory of Open Access Journals (Sweden)

    Vitkovic Pavol

    2016-01-01

    Full Text Available The main part of the heat transfer in a cooling tower is in a fill zone. This one is consist of a cooling fill. For the cooling tower is used a film fill or grid fill or splash fill in the generally. The grid fill has lower heat transfer performance like film fill usually. But their advantage is high resistance to blockage of the fill. The grid fill is consisted with independent layers made from plastic usually. The layers consist of several bars connected to the different shapes. For experiment was used the rhombus shape. The drops diameter was measured above and below the Grid fill.

  1. Mobility of O$_2^-$ ions in supercritical Ar: Experiment and Molecular Dynamics Simulations

    CERN Document Server

    Borghesani, A F

    2008-01-01

    A new analysis and new Molecular Dynamics (MD) simulations of the measurements of the mobility $\\mu_{i}$ of O$_{2}^{-} $ ions in dense supercritical Ar gas are reported. $\\mu_{i}$ shows a marked dependence on the distance from the critical temperature $T_{c}.$ A mobility defect appears as a function of the gas density and its maximum value occurs below the critical density. The locus of points of maximum mobility defect in the $P-T$ plane appears on the extrapolation of the coexistence curve into the single-phase region. MD simulations quantitatively reproduce the mobility defect near $T_{c}.$

  2. High-order harmonic generation in Ar and Ne with a 45fs intense laser field

    Institute of Scientific and Technical Information of China (English)

    徐至展; 王迎松; 翟侃; 李学信; 刘亚青; 杨晓东; 张正泉; 李儒新; 张文琦

    1999-01-01

    Experimental results of high-order harmonic generation (HHG) in Ar and Ne gas driven with a 45fs Ti: sapphire laser are presented. The shortest-wavelength harmonic emission corresponding to the 91st order harmonic (8.63nm) is observed in argon. In neon, the harmonics up to order 131 (5.99nm) is also observed. The effects of gas density, laser intensity, free electron and the focusing geometry parameters of the laser beam on the process of harmonic generation are investigated. The direct experimental evidence that an increased electron density causes a degenerated harmonic radiation is obtained.

  3. Multidiffusion mechanisms for noble gases (He, Ne, Ar) in silicate glasses and melts in the transition temperature domain: Implications for glass polymerization

    Science.gov (United States)

    Amalberti, Julien; Burnard, Pete; Laporte, Didier; Tissandier, Laurent; Neuville, Daniel R.

    2016-01-01

    Noble gases are ideal probes to study the structure of silicate glasses and melts as the modifications of the silicate network induced by the incorporation of noble gases are negligible. In addition, there are systematic variations in noble gas atomic radii and several noble gas isotopes with which the influence of the network itself on diffusion may be investigated. Noble gases are therefore ideally suited to constrain the time scales of magma degassing and cooling. In order to document noble gas diffusion behavior in silicate glass, we measured the diffusivities of three noble gases (4He, 20Ne and 40Ar) and the isotopic diffusivities of two Ar isotopes (36Ar and 40Ar) in two synthetic basaltic glasses (G1 and G2; 20Ne and 36Ar were only measured in sample G1). These new diffusion results are used to re-interpret time scales of the acquisition of fractionated atmospheric noble gas signatures in pumices. The noble gas bearing glasses were synthesized by exposing the liquids to high noble gas partial pressures at high temperature and pressure (1750-1770 K and 1.2 GPa) in a piston-cylinder apparatus. Diffusivities were measured by step heating the glasses between 423 and 1198 K and measuring the fraction of gas released at each temperature step by noble gas mass spectrometry. In addition we measured the viscosity of G1 between 996 and 1072 K in order to determine the precise glass transition temperature and to estimate network relaxation time scales. The results indicate that, to a first order, that the smaller the size of the diffusing atom, the greater its diffusivity at a given temperature: D(He) > D(Ne) > D(Ar) at constant T. Significantly, the diffusivities of the noble gases in the glasses investigated do not display simple Arrhenian behavior: there are well-defined departures from Arrhenian behavior which occur at lower temperatures for He than for Ne or Ar. We propose that the non-Arrhenian behavior of noble gases can be explained by structural modifications

  4. The thermal history of the Lhasa Block, South Tibetan Plateau based on FTD and Ar-Ar dating

    CERN Document Server

    Yang, T F; Lo Chong Huah; Chung, S L; Tien, R L; Xu, R; Deng, W

    1999-01-01

    Twelve basement samples were collected from South Tibet Plateau for FTD and Ar-Ar analysis to demonstrate their uplifting history since Cenozoic era. The preliminary results from different minerals with different closure temperatures, including apatite and zircon for fission-track dating, and K-feldspar, biotite for Ar-Ar dating, show that at least four stages of thermal history can be recognized in the studied area.

  5. Calibration of Nu-Instruments Noblesse multicollector mass spectrometers for argon isotopic measurements using a newly developed reference gas

    Science.gov (United States)

    Coble, M.A.; Grove, M.; Calvert, A.T.

    2011-01-01

    The greatest challenge limiting 40Ar/39Ar multicollection measurements is the availability of appropriate standard gasses to intercalibrate detectors. In particular, use of zoom lens ion-optics to steer and focus ion beams into a fixed detector array (i.e., Nu Instruments Noblesse) makes intercalibration of multiple detectors challenging because different ion-optic tuning conditions are required for optimal peak shape and sensitivity at different mass stations. We have found that detector efficiency and mass discrimination are affected by changes in ion-optic tuning parameters. Reliance upon an atmospheric Ar standard to calibrate the Noblesse is problematic because there is no straightforward way to relate atmospheric 40Ar and 36Ar to measurements of 40Ar and 39Ar if they are measured on separate detectors. After exploring alternative calibration approaches, we have concluded that calibration of the Noblesse is best performed using exactly the same source, detector, and ion-optic tuning settings as those used in routine 40Ar/39Ar analysis. To accomplish this, we have developed synthetic reference gasses containing 40Ar, 39Ar and 38Ar produced by mixing gasses derived from neutron-irradiated sanidine with an enriched 38Ar spike. We present a new method for calibrating the Noblesse based on use of both atmospheric Ar and the synthetic reference gasses. By combining atmospheric Ar and synthetic reference gas in different ways, we can directly measure 40Ar/39Ar, 38Ar/39Ar, and 36Ar/39Ar correction factors over ratios that vary from 0.5 to 460. These correction factors are reproducible to better than ??0.5??? (2?? standard error) over intervals spanning ~24h but can vary systematically by ~4% over 2weeks of continuous use when electron multiplier settings are held constant. Monitoring this variation requires daily calibration of the instrument. Application of the calibration method to 40Ar/39Ar multicollection measurements of widely used sanidine reference materials

  6. 77 FR 10373 - Greenhouse Gas Reporting Program: Electronics Manufacturing: Revisions to Heat Transfer Fluid...

    Science.gov (United States)

    2012-02-22

    ... AGENCY 40 CFR Part 98 RIN 2060-AR09 Greenhouse Gas Reporting Program: Electronics Manufacturing... category of the Greenhouse Gas Reporting Rule related to fluorinated heat transfer fluids. More... INFORMATION CONTACT: Carole Cook, Climate Change Division, Office of Atmospheric Programs...

  7. Ar + NO microwave plasmas for Escherichia coli sterilization

    Energy Technology Data Exchange (ETDEWEB)

    Hueso, Jose L; Rico, Victor J; Cotrino, Jose; Gonzalez-Elipe, Agustin R [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Centro de Investigaciones Cientificas Isla de la Cartuja, Avda. Americo Vespucio 49, 41092 Sevilla (Spain); Frias, Jose E [Instituto de BioquImica Vegetal y FotosIntesis (IBVF-CSIC). Centro de Investigaciones CientIficas Isla de la Cartuja. Avda Americo Vespucio, 49, 41092 Sevilla (Spain)], E-mail: jhueso@icmse.csic.es

    2008-05-07

    Ar + NO microwave discharges are used for sterilization and the results are compared with additional experiments with Ar, O{sub 2} and N{sub 2}-O{sub 2} plasma mixtures. The NO{sup *} species produced in the Ar-NO mixtures remain up to long distances from the source, thus improving the sterilization efficiency of the process. E. coli individuals exposed to the Ar + NO plasma undergo morphological damage and cell lysis. Combined effects of etching (by O{sup *} and Ar{sup *} species) and UV radiation (from deactivation of NO{sup *} species) are responsible for the higher activity found for this plasma mixture. (fast track communication)

  8. Ar-Ar and Rb-Sr Ages of the Tissint Olivine-phyric Martian Shergottite

    Science.gov (United States)

    Park, J.; Herzog, G. F.; Nyquist, L. E.; Shih, C.-Y.; Turin, B.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III; Agee, C.

    2013-01-01

    The fifth martian meteorite fall, Tissint, is an olivine-phyric shergottite that contains olivine macrocrysts (approximately 1.5 mm) [1]. [2] reported the Sm-Nd age of Tissint as 596 plus or minus 23 Ma along with Rb-Sr data that defined no isochron. [3] reported Lu-Hf and Sm-Nd ages of 583 plus or minus 86 Ma and 616 plus or minus 67 Ma, respectively. The cosmic-ray exposure ages of Tissint are 1.10 plus or minus 0.15 Ma based on 10Be [4], and 1.0-1.1 Ma, based on 3He, 21Ne, and 38Ar [5,6].We report Ar-Ar ages and Rb-Sr data.

  9. Modeling of Filling and Solidification Process for TiAl Exhaust Valves During Suction Casting

    Institute of Scientific and Technical Information of China (English)

    Chao XIONG; Yingche MA; Bo CHEN; Kui LIU; Yiyi LI

    2013-01-01

    Investment and suction casting (ISC) represents an economic and promising process route to fabricate automotive exhaust valves ofγ-TiAl based alloys,but information available on the metal flow and the temperature changes during mould filling and solidification process for the ISC process is meager.A sequentially coupled mathematical flow-thermal model,based on the commercial finite-volume/finite-difference code FLOW-3D and the finite-element code PROCAST,has been developed to investigate the ISC process.In term of calculating the flow and temperature fields during the filling and solidification stages,potential defects including the gas bubbles and the surface air entrainment occurred in the mould filling process and the shrinkage porosities formed in the solidification process are predicted and the reasons for the formation of these defects are also analyzed.The effects of filling pressure difference control methods and moulds on gas bubble and surface air entrainment behavior are presented.It is found that by changing the filling pressure difference control methods from general suction casting to "air leakage" suction casting and reducing air leakage flow rates,the gas bubbles are eliminated effectively,and the surface air entrainment attenuate dramatically.With resort to a mould with a tetragonal runner,the surface air entrainment decrease to the lowest level.Finally,the water analogue and suction casting experiments of exhaust valves are implemented for further validation of the simulation results.

  10. The dynamic response of carbon fiber-filled polymer composites

    Directory of Open Access Journals (Sweden)

    Patterson B.

    2012-08-01

    Full Text Available The dynamic (shock responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE composite to 18.6 GPa in the through-thickness direction, in which the shock propagates normal to the fibers. The data are best represented by a linear Rankine-Hugoniot fit: Us = 2.87 + 1.17 ×up(ρ0 = 1.536g/cm3. The shock wave structures were found to be highly heterogeneous, both due to the anisotropic nature of the fiber-epoxy microstructure, and the high degree of void volume. Plate impact experiments were also performed on a carbon fiber-filled phenolic (CP composite to much higher shock input pressures, exceeding the reactants-to-products transition common to polymers. The CP was found to be stiffer than the filament-wound CE in the unreacted Hugoniot regime, and transformed to products near the shock-driven reaction threshold on the principal Hugoniot previously shown for the phenolic binder itself. [19] On-going research is focused on interrogating the direction-dependent dyanamic response and dynamic failure strength (spall for the CE composite in the TT and 0∘ (fiber directions.

  11. Diagnosis parameters of mold filling pattern for optimization of a casting system

    OpenAIRE

    2012-01-01

    For optimal design of a gating system, the setting of diagnosis parameters is very important. In this study, the permanent mold casting process was selected because most of the other casting processes have more complicated factors that influence the mold filling pattern compared to the permanent mold casting process, such as the surface roughness of mold, gas generation from the mold wash and binder of sand mold, and the gas permeability through a sand mold, etc. Two diagnosis parameters (fl...

  12. Pengaruh Strategi Pengembangan Mutu Dan Kompensasi Terhadap Kinerja Guru Di SMK MVP ARS Internasional Bandung

    Directory of Open Access Journals (Sweden)

    Suryana Suryana

    2016-11-01

      The Influence of Quality Development Strategy and Compensation on Teachers’ Performance at SMK MVP ARS International Bandung, is  a research to get to know the result of teacher’ quality development strategy, the compensastion for the teachers, the performance of teachers and the influence of the tachers’ development strategy and compensastion on teachers’ performance at SMK MVP ARS Internasional Bandung. The methods used in this research is qualitative methods where the analysis unit is population of teaching staff without sampling because all the teachers filled out the questionaires.Based on the result of research indicates that teachers’ quality development strategy at SMK MVP ARS International Bandung is correlated to the compensation received by the teachers. So it has positive effect on the teacher’s performance, techer’s quality development strategy and compensastion simultinuously influence on the teacher’s development. And partially compensation has larger influence on teahers’ performance than quality development.By using SPSS software, it is resulted; partially, the influence of teacher’s developement program on performance is 0,010 or 1% and compensation on teachers’ performance is 0,572 atau 57,20%, the value of influence in simultant between techers’ development and, compensation on teacher’s performance is0,329 or 32,90%, but the correlation between quality development strategy and compensation is  0,148%.   Key Words : Quality Development, Compensation and Performance

  13. Enseñar a ser

    OpenAIRE

    García Barreno, Pedro

    2004-01-01

    El «Informe Delors», cuyo texto fue presentado hace ahora diez años, señala que cualquier proyecto educativo para el siglo XXI debe contemplar dos acciones. «Enseñar a conocer, a hacer, a vivir juntos, a ser», y garantizar el acceso de todos a ello. El siglo que concluyó apenas media docena de años, ha estado cargado de inmensas paradojas: entre grandes males, extraordinarios logros y no pocas esperanzas inalcanzadas. Marcado por dos guerras mundiales, po...

  14. Weiss oscillations and particle-hole symmetry at the half-filled Landau level

    CERN Document Server

    Cheung, Alfred K C; Mulligan, Michael

    2016-01-01

    Particle-hole symmetry in the lowest Landau level of the two-dimensional electron gas requires the electrical Hall conductivity to equal $\\pm e^2/2h$ at half-filling. We study the consequences of weakly broken particle-hole symmetry for magnetoresistance oscillations about half-filling in the presence of an applied periodic one-dimensional electrostatic potential. At fixed electron density, the oscillation minima are asymmetrically biased towards higher magnetic fields, while at fixed magnetic field, the oscillations occur symmetrically as the electron density is varied about half-filling. We find an approximate "sum rule" obeyed for all pairs of oscillation minima that can be tested in experiment. We discuss the implications of our results and approximations for the description of the half-filled Landau level.

  15. Paleomagnetism, magnetic fabric, and 40Ar/39Ar dating of Pliocene and Quaternary ignimbrites in the Arequipa area, southern Peru

    Science.gov (United States)

    Paquereau-Lebti, Perrine; Fornari, Michel; Roperch, Pierrick; Thouret, Jean-Claude; Macedo, Orlando

    2008-07-01

    40Ar/39Ar ages and paleomagnetic correlations using characteristic remanent magnetizations (ChRM) show that two main ignimbrite sheets were deposited at 4.86 ± 0.07 Ma (La Joya Ignimbrite: LJI) and at 1.63 ± 0.07 Ma (Arequipa Airport Ignimbrite: AAI) in the Arequipa area, southern Peru. The AAI is a 20-100 m-thick ignimbrite that fills in the Arequipa depression to the west of the city of Arequipa. The AAI is made up of two cooling units: an underlying white unit and an overlying weakly consolidated pink unit. Radiometric data provide the same age for the two units. As both units record exactly the same well-defined paleomagnetic direction (16 sites in the white unit of AAI: Dec = 173.7; Inc = 31.2; α95 = 0.7; k = 2749; and 10 sites in the pink unit of AAI; Dec = 173.6; Inc = 30.3; α95 = 1.2; k = 1634), showing no evidence of secular variation, the time gap between emplacement of the two units is unlikely to exceed a few years. The >50 m thick well-consolidated white underlying unit of the Arequipa airport ignimbrite provides a very specific magnetic zonation with low magnetic susceptibilities, high coercivities and unblocking temperatures of NRM above 580°C indicating a Ti-poor titanohematite signature. The Anisotropy of Magnetic Susceptibility (AMS) is strongly enhanced in this layer with anisotropy values up to 1.25. The fabric delineated by AMS was not recognized neither in the field nor in thin sections, because most of the AAI consists in a massive and isotrope deposit with no visible textural fabric. Pumices deformation due to welding is only observed at the base of the thickest sections. AMS within the AAI ignimbrite show a very well defined pattern of apparent imbrications correlated to the paleotopography, with planes of foliation and lineation dipping often at more than 20° toward the expected vent, buried beneath the Nevado Chachani volcanic complex. In contrast with the relatively small extent of the thick AAI, the La Joya ignimbrite covers large

  16. Contraction stresses of composite resin filling materials.

    Science.gov (United States)

    Hegdahl, T; Gjerdet, N R

    1977-01-01

    The polymerization shrinkage of composite resin filling materials and the tensile stresses developed when the shrinkage is restrained were measured in an in vitro experiment. This allows an estimation to be made of the forces exerted upon the enamel walls of cavities filled with the resin in the acid etch technique. The results indicate that the stresses acting on the enamel are low compared to the tensile strength of the enamel.

  17. Ar plasma treated polytetrafluoroethylene films for a highly efficient triboelectric generator

    Science.gov (United States)

    Kim, Dong Yeong; Kim, Hyun Soo; Jung, Jong Hoon

    2016-12-01

    We report an Ar plasma treated polytetrafluoroethylene (PTFE) film based triboelectric device for a highly enhanced electric power generation. The plasma treatment of the PTFE in flowing Ar gas results in a sharp increase in surface roughness ( 46 nm), as compared with the as-received film ( 25 nm). In addition, the F ion content decreases whereas the O ion increases with increasing plasma reaction time. Because of the increased number of polar O ions, the surface becomes hydrophilic, as confirmed by water contact angle measurements. After the Ar plasma treatment, the PTFE based triboelectric device, which is periodically contacted with and separated from the ITO electrode, generates a 715 V open-circuit voltage and a 16 μA closed-circuit current, which are almost 79 and 32 times larger than those for as-received PTFE based device. Using the Ar plasma treated PTFE based triboelectric generator, we can turn on the 120 light emitting diodes (LEDs) without any batteries.

  18. Unveiling Turrialba (Costa Rica) volcano's latest geological evolution through new 40Ar/39Ar, ages

    Science.gov (United States)

    Ruiz Cubillo, P.; Turrin, B. D.; Soto, G. J.; Del Potro, R.; Gagnevin, D.; Gazel, E.; Mora Fernandez, M.; Carr, M. J.; Swisher, C. C.

    2010-12-01

    Step-heating 40Ar/39Ar dating experiments on whole rock matrix were performed on samples from eight key lava flow units from Turrialba, the easternmost volcano of the Central Volcanic Range of Costa Rica. Our results, together with available corrected 14C ages, recent mapping and new geochemical analyses, are part of a study to reconstruct Turrialba’s evolution. The project is being conducted as part of wider studies because of the increase in volcanic activity during the last three years. The geochemical compositions of the lava flow units span the range from basalts to dacites, and commonly have high K2O concentrations, making them good candidates for 40Ar/39Ar radiometric dating. The ages reported here correspond to the Paleo Turrialba (600-250 ka) and Neo Turrialba (< 250 ka) temporal stages. Sample TUR-38 (251 ± 4 ka) belongs to the latest unit of Paleo Turrialba stage, known as Finca Liebres volcano, while the remaining seven samples belong to Neo Turrialba: TUR-30 (99 ± 3 ka), TUR-19 (90 ± 4 ka), TUR-32 (62 ± 2 ka) TUR-33 (61 ± 2 ka), TUR-12 (25 ± 1.9 ka), TUR-36 (10 ± 3 ka) and TUR-08 (3 ± 3 ka). All the obtained ages in this study are in agreement with the local stratigraphy and prior 14C age determinations, adding robustness to our results. According to ages obtained and the areal distribution of the sampled units, the most important construction period of the massif was during the Neo-Turrialba stage which has passed through two important constructing episodes, around 100-60 ka and 10 ka-present. Although our results include some very young ages, all of them meet the established evaluation criteria used for plateau and isochron ages, commonly used for 40Ar/39Ar dating. Furthermore, we used a protocol that closely monitors the mass spectrometer mass discrimination during the measurements to provide additional control. Three of the eight 40Ar/39Ar ages reported here are remarkably young (25 ka or less). Two of those are the samples with the

  19. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  20. N 2-Ar-He compositions in fluid inclusions: Indicators of fluid source

    Science.gov (United States)

    Norman, David I.; Musgrave, John A.

    1994-02-01

    A quadrupole mass spectrometer was used to measure bulk samples of conservative gas species N 2, Ar, and He in fluid inclusions from a variety of hydrothermal systems. Analyses of these tracer elements help determine (1) if gases extracted by bulk inclusion analyses can provide accurate measurement of N 2-Ar-He in active and fossil geothermal systems, (2) if hydrothermal fluids associated with paleogeothermal systems in a continental setting follow N 2ArHe systematics similar to th the western Pacific Rim active geothermal systems, specifically New Zealand, and (3) whether different deposit types systematically vary with regard to N 2ArHe. The N 2ArHe ratios of fluid inclusion volatiles released from recently deposited minerals from the Valles system are similar to those of present day Valles thermal waters. Those inclusion samples from deep within the Valles system, below a regional aquitard, increase in N 2. Compositions for inclusions from the Questa and Copper Flat-porphyry deposits are N 2-rich, similar to those of arc-related volcanic gases, whereas those from Taylor Creek Sn deposit appear to be mixtures of magmatic and crustal components. N 2-Ar-He ratios of the Precambrian Tribag deposit suggest a basalt source, but significant levels of self-generated He from U and Th in the inclusion fluids are also possible. Inclusions from two epithermal deposits with low-salinity inclusions have N 2-Ar-He ratios trending towards air-saturated meteoric waters (ASW), and those inclusions with higher salinities indicate minor to no ASW component. The N 2-Ar-He ratios in Fresnillo and Cochiti inclusions, which have magmatic helium isotopic ratios, indicate additions of magmatic gases to meteoric fluids. Inclusions from sediment-hosted deposits that contain hydrocarbon-bearing brines are He-rich, as are meteoric waters with a long residence time in the crust. At relevant pressure-temperature-composition conditions, Henry's Law constants of N 2, Ar, and He

  1. Grain filling, starch degradation and feeding value of maize for ruminants

    NARCIS (Netherlands)

    Ali, M.

    2013-01-01

    Keywords; Maize (Zea mays L), Genotypes, Grain filling, Growth temperature, Kernels, Gas production, Starch degradation, Oven-drying, Silage, Ensiling temperature, Ensiling duration, Feeding value, Lactating cows Maize (Zea mays L.) is a major component in the ration of dairy cows in many parts of

  2. Optical frequency standard using acetylene-filled hollow-core photonic crystal fibers

    DEFF Research Database (Denmark)

    Triches, Marco; Michieletto, Mattia; Hald, Jan;

    2015-01-01

    Gas-filled hollow-core photonic crystal fibers are used to stabilize a fiber laser to the 13C2H2 P(16) (ν1+ν3) transition at 1542 nm using saturated absorption. Four hollow-core fibers with different crystal structure are compared in terms of long term lock-point repeatability and fractional...

  3. Electron attachment of oxygen in a drift chamber filled with xenon + 10% methane

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, Y.; Hayashibara, I.; Ohsugi, T.; Sakanoue, T.; Taketani, A.; Terunuma, N.; Suzuki, Y.; Tsukamoto, A.; Yamamoto, H.; Fukushima, Y.

    1988-06-01

    The existence of O/sub 2/ contamination attenuates the pulse height and degrades its resolution in a drift chamber filled with xenon-methane (90/10) gas. The first measurement of the electron attachment coefficient due to oxygen in such a mixture is reported.

  4. Electron attachment of oxygen in a drift chamber filled with xenon + 10% methane

    Science.gov (United States)

    Chiba, Y.; Hayashibara, I.; Ohsugi, T.; Sakanoue, T.; Taketani, A.; Terunuma, N.; Suzuki, Y.; Tsukamoto, A.; Yamamoto, H.; Fukushima, Y.; Kohriki, T.; Nakamura, S.; Sakuda, M.; Watase, Y.

    1988-06-01

    The existence of O 2 contamination attenuates the pulse height and degrades its resolution in a drift chamber filled with xenon-methane (90/10) gas. The first measurement of the electron attachment coefficient due to oxygen in such a mixture is reported.

  5. The Answer to Rising Gas Prices...Nitrogen?

    Science.gov (United States)

    Lee, Frank; Batelaan, Herman

    2010-01-01

    It is claimed by the company NitroFill and the GetNitrogen Institute that filling car tires with nitrogen improves gas mileage considerably. The reason given is that oxygen leaks out of tires so that the increased rolling friction causes a reduced gas mileage. Because it is hard to do an actual road test, we report on a simple visual test of…

  6. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis.

    Science.gov (United States)

    Castillo, Ana F; Orlando, Ulises; Helfenberger, Katia E; Poderoso, Cecilia; Podesta, Ernesto J

    2015-06-15

    The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.

  7. Coal liquefaction and gas conversion: Proceedings. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    Volume I contains papers presented at the following sessions: AR-Coal Liquefaction; Gas to Liquids; and Direct Liquefaction. Selected papers have been processed separately for inclusion in the Energy Science and Technology Database.

  8. Astronomical calibration of 40Ar/39Ar reference minerals using high-precision, multi-collector (ARGUSVI) mass spectrometry

    Science.gov (United States)

    Phillips, D.; Matchan, E. L.; Honda, M.; Kuiper, K. F.

    2017-01-01

    The new generation of multi-collector mass spectrometers (e.g. ARGUSVI) permit ultra-high precision (1%) in 40K decay constants and the ages of natural reference minerals that form the basis of the technique. For example, reported ages for widely used 40Ar/39Ar reference materials, such as the ca. 28 Ma Fish Canyon Tuff sanidine (FCTs) and the ca. 1.2 Ma Alder Creek Rhyolite sanidine (ACRs), vary by >1%. Recent attempts to independently calibrate these reference minerals have focused on K-Ar analyses of the same minerals and inter-comparisons with astronomically tuned tephras in sedimentary sequences and U-Pb zircon ages from volcanic rocks. Most of these studies used older generation (effectively single-collector) mass spectrometers that employed peak-jumping analytical methods to acquire 40Ar/39Ar data. In this study, we reassess the inter-calibration and ages of commonly used 40Ar/39Ar reference minerals Fish Canyon Tuff sanidine (FCTs), Alder Creek Rhyolite sanidine (ACRs) and Mount Dromedary biotite (MD2b; equivalent to GA-1550 biotite), relative to the astronomically tuned age of A1 Tephra sanidine (A1Ts), Faneromeni section, Crete (Rivera et al., 2011), using a multi-collector ARGUSVI mass spectrometer. These analyses confirm the exceptional precision capability (0.1% in the 40Ar/39Ar ages of reference minerals without consideration of recoil artefacts, thus limiting the benefits of high precision multi-collector analyses. Significant improvement to the accuracy of the 40Ar/39Ar method (<0.1%) will require further inter-laboratory 40Ar/39Ar studies utilizing multi-collector mass spectrometry, additional constraints on recoil 39ArK loss from reference minerals, further resolution of discrepancies between astronomically tuned sedimentary successions and refinement of the 238U/206Pb zircon age cross-calibration approach.

  9. New high-precision 40Ar/39Ar ages on Oligocene volcanic rocks of northwestern Kenya

    Science.gov (United States)

    Brown, Francis H.; Jicha, Brian R.

    2016-02-01

    New, high-precision 40Ar/39Ar ages from volcanic rocks in northwestern Kenya are provided for some areas of exposure in this remote area. We report seven 40Ar/39Ar ages generated from single crystal total fusion experiments on alkali feldspar separated from volcanic rocks in the Mogila, Songot, and Lokwanamur Ranges and the Gatome valley. A rhyolite from the lower part of the sequence in the Mogila Range yielded ages of 32.31 ± 0.06 Ma and 32.33 ± 0.07 Ma, and a rhyolite near the top of that sequence yielded 31.67 ± 0.04 Ma. A single sample from the Songot Range yielded an age of 32.49 ± 0.07 Ma, slightly older than the rocks collected from Mogila. In both ranges the early Oligocene rhyolites are underlain by basalts, as is also the case in the Labur Range. Ages of 25.95 ± 0.03 Ma, 25.91 ± 0.04 Ma, and 27.15 ± 0.03 Ma were measured on alkali feldspar from rhyolites from the Lokwanamur Range, and the nearby Gatome valley. All of these rocks are part of an episode of widespread volcanism in northwestern Kenya in the mid-to late Oligocene that is not currently known from the Ethiopian Rift Valley.

  10. Identification of an AR mutation-negative class of androgen insensitivity by determining endogenous AR activity

    NARCIS (Netherlands)

    Hornig, N.C.; Ukat, M.; H.U. Schweikert (H.); O. Hiort (Olaf); Werner, R.; S.L.S. Drop (Stenvert); M.L. Cools (Martine); I.A. Hughes (Ieuan A.); L. Audí (Laura); S.F. Ahmed (S. Faisal); Demiri, J.; Rodens, P.; Worch, L.; Wehner, G.; Kulle, A.E.; Dunstheimer, D.; Müller-Roßberg, E.; T. Reinehr (Thomas); Hadidi, A.T.; Eckstein, A.K.; Van Der Horst, C.; Seif, C.; R. Siebert (Reiner); O. Ammerpohl (Ole); P-M. Holterhus (Paul-Martin)

    2016-01-01

    textabstractContext: Only approximately 85%of patients with a clinical diagnosis complete androgen insensitivity syndrome and less than 30%with partial androgen insensitivity syndrome can be explained by inactivating mutations in the androgen receptor (AR) gene. Objective: The objective of the study

  11. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Ha; Kim, Hyun-Jin; Park, Choon-Sang; Tae, Heung-Sik, E-mail: hstae@ee.knu.ac.kr [School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Shin, Bhum Jae [Department of Electronics Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Seo, Jeong Hyun [Department of Electronics Engineering, Incheon National University, Incheon 406-772 (Korea, Republic of)

    2015-09-15

    In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ) device to individually control the plasmas in both fragmentation (or active) and recombination (or passive) regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM). Plasma composition was measured by optical emission spectroscopy (OES). In addition to a large number of Ar and He spectra lines, we observed some spectra of C{sub 2} and CH species for fragmentation and N{sub 2} (second positive band) species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2{sup nd} grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  12. Atmospheric pressure plasma polymerization using double grounded electrodes with He/Ar mixture

    Directory of Open Access Journals (Sweden)

    Dong Ha Kim

    2015-09-01

    Full Text Available In this study, we have proposed the double grounded atmospheric pressure plasma jet (2G-APPJ device to individually control the plasmas in both fragmentation (or active and recombination (or passive regions with a mixture of He and Ar gases to deposit organic thin films on glass or Si substrates. Plasma polymerization of acetone has been successfully deposited using a highly energetic and high-density 2G-APPJ and confirmed by scanning electron microscopy (SEM. Plasma composition was measured by optical emission spectroscopy (OES. In addition to a large number of Ar and He spectra lines, we observed some spectra of C2 and CH species for fragmentation and N2 (second positive band species for recombination. The experimental results confirm that the Ar gas is identified as a key factor for facilitating fragmentation of acetone, whereas the He gas helps the plume of plasma reach the substrate on the 2nd grounded electrode during the plasma polymerization process. The high quality plasma polymerized thin films and nanoparticles can be obtained by the proposed 2G-APPJ device using dual gases.

  13. The transparent microstrip gas counter

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroyuki, E-mail: leo@q.t.u-tokyo.ac.j [University of Tokyo, Tokyo 113-8656 (Japan); Fujita, Kaoru; Fujiwara, Takeshi [University of Tokyo, Tokyo 113-8656 (Japan); Niko, Hisako; Guerard, Bruno [Institute of Max von Laue and Paul Langevin, BP 156, 38042 Grenoble, Cedex 9 (France); Fraga, Francisco [Departamento de Fisica, LIP-Coimbra, Universidade de Coimbra, 3000 Coimbra (Portugal); Iyomoto, Naoko [University of Tokyo, Tokyo 113-8656 (Japan)

    2010-11-01

    Conventional MSGCs are made of metal electrodes that might absorb or reflect optical photons. If the electrodes are made of transparent material like ITO, we could take advantage of optical readout. A gas scintillation proportional counter made of ITO MSGC is fabricated and tested where both optical and charge signals are obtained. We have selected a multi-grid structure that can avoid charge-up problem with normal transparent glass substrate. Test results with Ar and CF{sub 4} gas mixture showed a stable gas gain of {approx}2800 and {approx}110 optical photons for 6 keV X-rays. Position sensing with PSPMT has successfully been demonstrated.

  14. Comparison of vacuum ultra-violet emission of Ar/CF4 and Ar/CF3I capacitively coupled plasmas

    Science.gov (United States)

    Zotovich, A.; Proshina, O.; el Otell, Z.; Lopaev, D.; Rakhimova, T.; Rakhimov, A.; de Marneffe, J.-F.; Baklanov, M. R.

    2016-10-01

    Spectra in the vacuum-ultra violet range (VUV, 30 nm-200 nm) as well as in the ultra-violet(UV) and visible ranges (UV+vis, 200 nm-800 nm) were measured from Ar/CF3I and Ar/CF4 discharges. The discharges were generated in an industrial 300 mm capacitively coupled plasma source with 27 MHz radio-frequency power. It was seen that the measured spectra were strongly modified. This is mainly due to absorption, especially by CF3I, and Ar self-trapping along the line of sight, towards the detector and in the plasma itself. The estimated unabsorbed VUV spectra were revealed from the spectra of mixtures with low fluorocarbon gas content by means of normalization with unabsorbed I* emission, at 206 nm, and CF2\\ast band (1B1(0,v‧,0){{\\to}1} A1(0,{{\\text{v}}\\prime \\prime} ,0)) emission between 230 nm and 430 nm. Absolute fluences of UV CF2\\ast emission were derived using hybrid 1-dimensional (1D) particle-in-cell (PIC) Monte-Carlo (MC) model calculations. Absolute calibration of the VUV emission was performed using these calculated values from the model, which has never been done previously for real etch conditions in an industrial chamber. It was seen that the argon resonant lines play a significant role in the VUV spectra. These lines are dominant in the case of etching recipes close to the standard ones. The restored unabsorbed spectra confirm that replacement of conventional CF4 etchant gas with CF3I in low-k etching recipes leads to an increase in the overall VUV emission intensity. However, emission from Ar exhibited the most intense peaks. Damage to low-k SiCOH glasses by the estimated VUV was calculated for blanket samples with pristine k-value of 2.2. The calculations were then compared with Fourier transform infrared (FTIR) data for samples exposed to the similar experimental conditions in the same reactor. It was shown that Ar emission plays the most significant role in VUV-induced damage.

  15. A method for intercalibration of U-Th-Pb and 40Ar- 39Ar ages in the Phanerozoic

    Science.gov (United States)

    Villeneuve, Mike; Sandeman, Hamish A.; Davis, William J.

    2000-12-01

    The increasing analytical precision of 40Ar- 39Ar geochronological data and its use in studies that combine U-Pb and 40Ar- 39Ar data has necessitated derivation of a means to intercalibrate ages between the two isotopic systems. The primary determinants inhibiting accurate cross calibration are uncertainty in decay constant values and uncertainty in 40Ar∗/ 40K (usually presented as apparent age) for 40Ar- 39Ar standards, notably those derived from the Fish Canyon Tuff. By utilizing a monazite- and biotite bearing Oligocene ash flow tuff (MAC-83) as the primary standard material, precise U-Th-Pb and 40Ar- 39Ar ages can be derived. Because both isotopic systems should reflect closure during the instantaneous eruption event, the 24.21 ± 0.10 Ma 207Pb/ 235U age should match the age resulting from 40Ar- 39Ar biotite analysis. This forced equivalence will partly offset the effects of decay constant uncertainty. Furthermore, by co-irradiating Fish Canyon Tuff sanidine with MAC-83 biotite, the apparent age for Fish Canyon Tuff sanidine is back-calculated to 27.98 ± 0.15 Ma, relative to the MAC-83 207Pb/ 235U age. Hence, intercalibration between the two isotopic systems in a relative sense can be accomplished, allowing for a direct and valid comparison of ages. It is also shown that forcing equivalence of the two isotopic systems minimizes the effect of decay constant uncertainty for samples of Phanerozoic age.

  16. Seepage characteristics of collapse column fillings

    Institute of Scientific and Technical Information of China (English)

    Zhang Boyang; Bai Haibo; Zhang Kai

    2016-01-01

    With concealment and hysteresis, water-inrush from Karst collapse column has become an important security hazard of lower group coal mining in North China. Based on the MTS815.02 seepage test system, we analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings. The results show that:(1) The permeability of collapse column fillings is of the order of 10?16–10?15 magni-tude and decreases with an increase in consolidation pressure and decrease in initial moisture content. (2) The essence of filling seepage law change is the change in porosity, and a power function relationship exists between the permeability ratio and porosity ratio. (3) With increasing confining pressure, the per-meability of fillings decreases. However, under low confining pressure (1.2–4 MPa), the change of confin-ing pressure has no obvious influence on the permeability.

  17. INFLUENCE OF FILLING WATER ON AIR CONCENTRATION

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; MA Fei; DAI Hui-chao

    2011-01-01

    The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway.The aerator may cease to protect against cavitation damages,and may even act as a generator of cavitation if it is fully filled by water.The experiments were conducted to investigate the influences of the geometric parameters,and then the filling water on the air concentration.The results show that the filling water,or the net cavity length,is closely related to the plunging jet length for a given aerator,and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators.Secondly,at the same ratio of Ln / Lj,the aerator with a larger height or a larger angle of ramp,or a larger bottom slope,would have a larger plunging jet length,and then a larger net cavity length based on the ratio of Ln / Lj.As a result,the large space of cavity,or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf=Lj- Ln.It is the space of the cavity that is the dominant factor to affect the air concentration of the flow.

  18. Identification and analysis of ARS function of six plant MARs

    Institute of Scientific and Technical Information of China (English)

    LI Hong; YANG Yutao; ZHANG Kewei; ZHENG Chengchao

    2004-01-01

    Six plant MARs isolated from tobacco and Arabdiposis were investigated for their ARS activity in yeast.The results showed that among the six plant MARs, only TM1 and AM4 had strong ARS activity which was almost the same as that of ARS from yeast chromosome. In order to further identify the core region of the two MARs for the ARS activity, a series of subclones were created by PCR strategy,and the corresponding subclones were designated as TM1-1,TM1-2, TM1-3, AM4-1, AM4-2 and AM4-3, respectively. Our studies revealed that TM1-3 and AM4-3 not only had higher ARS activity, but also displayed higher transformation frequency, plasmid stability and growth rate compared to their intact MARs, TM1 and AM4. These data present an important clue for further elucidating the relationship between MAR and ARS.

  19. Single-electron detachment cross sections in H{sup {minus}}+Ar

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.; Sen, A.; Matulioniene, A.S.R.; Fang, X. [Univ. of Toledo, OH (United States)

    1993-05-01

    Measurements of absolute cross sections for the single electron detachment ({sigma}{sub -1,0}) in collisions between H{sup -} and Ar in the energy range 5-50 keV are reported. A well-collimated H{sup -} ion beam is directed toward an Ar gas target and all three of the exiting scattered beam components (i.e. H{sup 0}, H{sup +} and H{sup -}) are measured simultaneously. Using the closure relation among the collision beam components, (H{sup 0}, H{sup -} and H{sup +}) the neutral detection efficiencies are determined at each energy and thereby we are able to report absolute single detachment cross sections. The single detachment cross sections {sigma}{sub -1,0} exhibit a broad maximum with a value of 1.78 x 10{sup -15} cm{sup 2} at an impact energy of 25 keV.

  20. Infrared absorption spectroscopy of the COAr complex

    Science.gov (United States)

    McKellar, A. R. W.; Zeng, Y. P.; Sharpe, S. W.; Wittig, C.; Beaudet, R. A.

    1992-05-01

    The rotation-vibration spectrum of the weakly bound complex COAr has been studied in the 2140 cm -1 region of the fundamental band of CO. Data were obtained from two different experiments: first, a pulsed slit-jet supersonic expansion and a tunable diode laser source; and second a long-path low-temperature static gas cell and a Fourier transform spectrometer. The low rotational temperature and narrow line width of the jet expansion data were complementary to the higher J-values and broad coverage of the static cell data. The observed spectrum was approximately that of a T-shaped near-prolate asymmetric rotor molecule. About 370 transitions were assigned to 6 perpendicular subbands with K = 3-2, 2-1, 1-0, 0-1, 1-2, and 2-3. No parallel (Δ K = 0) subbands were observed. The observed B rotational constant of the complex in its ground state, 0.0691 cm -1, corresponds to an effective intermolecular separation of about 3.850 Å. The observed A rotational constant of about 2.47 cm -1 is not too far from the overlineB value of the CO monomer, 1.92 cm -1, as expected for the approximately T-shaped effective geometry of the complex.

  1. Enseñar a ser

    Directory of Open Access Journals (Sweden)

    García Barreno, Pedro

    2004-09-01

    Full Text Available El «Informe Delors», cuyo texto fue presentado hace ahora diez años, señala que cualquier proyecto educativo para el siglo XXI debe contemplar dos acciones. «Enseñar a conocer, a hacer, a vivir juntos, a ser», y garantizar el acceso de todos a ello. El siglo que concluyó apenas media docena de años, ha estado cargado de inmensas paradojas: entre grandes males, extraordinarios logros y no pocas esperanzas inalcanzadas. Marcado por dos guerras mundiales, por genocidios, por la acelerada degradación de la biosfera o por la miseria de una masa de marginados frente al creciente bienestar de los privilegiados.…

  2. Plasma AR and abiraterone-resistant prostate cancer.

    Science.gov (United States)

    Romanel, Alessandro; Gasi Tandefelt, Delila; Conteduca, Vincenza; Jayaram, Anuradha; Casiraghi, Nicola; Wetterskog, Daniel; Salvi, Samanta; Amadori, Dino; Zafeiriou, Zafeiris; Rescigno, Pasquale; Bianchini, Diletta; Gurioli, Giorgia; Casadio, Valentina; Carreira, Suzanne; Goodall, Jane; Wingate, Anna; Ferraldeschi, Roberta; Tunariu, Nina; Flohr, Penny; De Giorgi, Ugo; de Bono, Johann S; Demichelis, Francesca; Attard, Gerhardt

    2015-11-01

    Androgen receptor (AR) gene aberrations are rare in prostate cancer before primary hormone treatment but emerge with castration resistance. To determine AR gene status using a minimally invasive assay that could have broad clinical utility, we developed a targeted next-generation sequencing approach amenable to plasma DNA, covering all AR coding bases and genomic regions that are highly informative in prostate cancer. We sequenced 274 plasma samples from 97 castration-resistant prostate cancer patients treated with abiraterone at two institutions. We controlled for normal DNA in patients' circulation and detected a sufficiently high tumor DNA fraction to quantify AR copy number state in 217 samples (80 patients). Detection of AR copy number gain and point mutations in plasma were inversely correlated, supported further by the enrichment of nonsynonymous versus synonymous mutations in AR copy number normal as opposed to AR gain samples. Whereas AR copy number was unchanged from before treatment to progression and no mutant AR alleles showed signal for acquired gain, we observed emergence of T878A or L702H AR amino acid changes in 13% of tumors at progression on abiraterone. Patients with AR gain or T878A or L702H before abiraterone (45%) were 4.9 and 7.8 times less likely to have a ≥50 or ≥90% decline in prostate-specific antigen (PSA), respectively, and had a significantly worse overall [hazard ratio (HR), 7.33; 95% confidence interval (CI), 3.51 to 15.34; P = 1.3 × 10(-9)) and progression-free (HR, 3.73; 95% CI, 2.17 to 6.41; P = 5.6 × 10(-7)) survival. Evaluation of plasma AR by next-generation sequencing could identify cancers with primary resistance to abiraterone.

  3. Optical diagnostics and mass spectrometry on the afterglow of an atmospheric pressure Ar/O$_2$ radiofrequency plasma used for polymer surface treatment

    CERN Document Server

    Duluard, Corinne Y; Hubert, Julie; Reniers, François

    2016-01-01

    In the context of polymer surface treatment, the afterglow of an atmospheric pressure Ar/O$_2$ radiofrequency plasma is characterized by optical emission spectroscopy, laser induced fluorescence and mass spectrometry. The influence of the O$_2$ gas flow rate and the source power on the plasma properties (gas temperature, Ar excitation temperature, relative concentrations of O atoms and OH radicals) are evaluated. We show that for plasma torch-to-substrate distances lower than 6 mm, the afterglow creates a protective atmosphere, thus the plasma gas composition interacting with the substrate is well controlled. For higher distances, the influence of ambient air can no longer be neglected and gradients in Ar, O$_2$ and N$_2$ concentrations are measured as a function of axial and vertical position.

  4. Form Filling with Self-Compacting Concrete

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2007-01-01

    a Bingham model with a yield stress and plastic viscosity. In this way the accuracy and ability of CFD to simulate the homogeneous flow on a realistic form filling scale is utilized compared to, e.g. a discrete particle flow approach which requires a much larger computer capacity, especially in three...... to the homogeneous form filling simulation provides a theoretical tool to assess parts of the formwork where there is a risk of blocking. The modelling approach has been applied to selected flow domains comprising standard test methods, the slump flow test and the L-box test, and form filling applications...... nuværende praksis for valg af materialer og støbemetoder er erfaringsbaseret; beregningsbaserede planlægningsmetoder forventes at kunne motivere en forøget anvendelse af SCC. Projektet har haft til formål at etablere modeller til simulering af formfyldning med SCC under hensyntagen til betonens flyde...

  5. Main species and chemical pathways in cold atmospheric-pressure Ar + H2O plasmas

    Science.gov (United States)

    Liu, Dingxin; Sun, Bowen; Iza, Felipe; Xu, Dehui; Wang, Xiaohua; Rong, Mingzhe; Kong, Michael G.

    2017-04-01

    Cold atmospheric-pressure plasmas in Ar + H2O gas mixtures are a promising alternative to He + H2O plasmas as both can produce reactive oxygen species of relevance for many applications and argon is cheaper than helium. Although He + H2O plasmas have been the subject of multiple experimental and computational studies, Ar + H2O plasmas have received less attention. In this work we investigate the composition and chemical pathways in Ar + H2O plasmas by means of a global model that incorporates 57 species and 1228 chemical reactions. Water vapor concentrations from 1 ppm to saturation (32 000 ppm) are considered in the study and abrupt transitions in power dissipation channels, species densities and chemical pathways are found when the water concentration increases from 100 to 1000 ppm. In this region the plasma transitions from an electropositive discharge in which most power is coupled to electrons into an electronegative one in which most power is coupled to ions. While increasing electronegativity is also observed in He + H2O plasmas, in Ar + H2O plasmas the transition is more abrupt because Penning processes do not contribute to gas ionization and the changes in the electron energy distribution function and mean electron energy caused by the increasing water concentration result in electron-neutral excitation and ionization rates changing by many orders of magnitude in a relatively small range of water concentrations. Insights into the main chemical species and pathways governing the production and loss of electrons, O, OH, OH(A) and H2O2 are provided as part of the study.

  6. HXeI and HXeH in Ar, Kr, and Xe matrices: experiment and simulation.

    Science.gov (United States)

    Zhu, Cheng; Niimi, Keisuke; Taketsugu, Tetsuya; Tsuge, Masashi; Nakayama, Akira; Khriachtchev, Leonid

    2015-02-07

    Experimental and theoretical studies of HXeI and HXeH molecules in Ar, Kr, and Xe matrices are presented. HXeI exhibits the H-Xe stretching bands at 1238.0 and 1239.0 cm(-1) in Ar and Kr matrices, respectively, that are blue-shifted from the HXeI band observed in a Xe matrix (1193 cm(-1)) by 45 and 46 cm(-1). These shifts are larger than those observed previously for HXeCl (27 and 16 cm(-1)) and HXeBr (37 and 23 cm(-1)); thus, the matrix effect is stronger for less stable molecules. The results for HXeI are qualitatively different from all previous results on noble-gas hydrides with respect to the frequency order between Ar and Kr matrices. For previously studied HXeCl, HXeBr, and HXeCCH, the H-Xe stretching frequency is reliably (by >10 cm(-1)) higher in an Ar matrix than in a Kr matrix. In contrast, the H-Xe stretching frequency of HXeI in an Ar matrix is slightly lower than that in a Kr matrix. HXeH absorbs in Ar and Kr matrices at 1203.2 and 1192.1 cm(-1) (the stronger band for a Kr matrix), respectively. These bands are blue-shifted from the stronger band of HXeH in a Xe matrix (1166 cm(-1)) by 37 and 26 cm(-1), and this frequency order is the same as observed for HXeCl, HXeBr, and HXeCCH but different from HXeI. The present hybrid quantum-classical simulations successfully describe the main experimental findings. For HXeI in the 〈110〉 (double substitution) site, the order of the H-Xe stretching frequencies (ν(Xe) matrices from a Xe matrix are well predicted (30 and 34 cm(-1)). Both in the theory and experiment, the order of the H-Xe stretching frequencies differs from the case of HXeCl, which suggests the adequate theoretical description of the matrix effect. For HXeH in the 〈100〉 (single substitution) site, the order of the frequencies is ν(Xe) matrices with respect to a Xe matrix (36 and 23 cm(-1)) are in a good agreement with the experiments. The present calculations predict an increase of the H-Xe stretching frequencies in the noble-gas matrices

  7. Gas accretion onto galaxies

    CERN Document Server

    Davé, Romeel

    2017-01-01

    This edited volume presents the current state of gas accretion studies from both observational and theoretical perspectives, and charts our progress towards answering the fundamental yet elusive question of how galaxies get their gas. Understanding how galaxies form and evolve has been a central focus in astronomy for over a century. These studies have accelerated in the new millennium, driven by two key advances: the establishment of a firm concordance cosmological model that provides the backbone on which galaxies form and grow, and the recognition that galaxies grow not in isolation but within a “cosmic ecosystem” that includes the vast reservoir of gas filling intergalactic space. This latter aspect in which galaxies continually exchange matter with the intergalactic medium via inflows and outflows has been dubbed the “baryon cycle”. The topic of this book is directly related to the baryon cycle, in particular its least well constrained aspect, namely gas accretion. Accretion is a rare area of ast...

  8. Simulation of atmospheric pressure microplasma in Ar on the basis of heat transfer

    Science.gov (United States)

    Yamasaki, Masanori; Yagisawa, Takashi; Tatsumi, Tetsuya; Makabe, Toshiaki

    2011-10-01

    In a decade, atmospheric pressure microplasmas have been applied to wide range of fields based on the characteristics of high plasma density. The underlying mechanism for sustaining a stable glow discharge, however, is not well understood. In this study, the microplasma characteristics at atmospheric pressure are numerically investigated, particularly focusing on a heat transfer in the whole system. We consider a capacitively coupled plasma with the characteristic size of several hundred micrometers, driven by radio frequency (13.56 MHz) in a cylindrical reactor under atmospheric pressure of pure Ar. A plasma fluid model is coupled with a neutral gas dynamics model including the temperature and flow in gas phase. A wall heating caused by energetic ions and metastables coming from the plasma is also incorporated in the model. Under a constant gas pressure, the local depletion of a neutral gas density occurs due to a gas heating, simply shown by ideal gas law. The influence of the local gas density on the structure of the microplasma will be mainly discussed in a periodic steady state.

  9. Non-Linear MDT Drift Gases like Ar/CO2

    CERN Document Server

    Aleksa, Martin

    1998-01-01

    Detailed measurements and simulations have been performed, investigating the properties of Ar/CO2 mixtures as a MDT drift gas. This note presents these measurements and compares them to other drift gases that have been simulated using GARFIELD, HEED and MAGBOLTZ.This note also describes systematic errors to be considered in the operation of precision drift chambers using such gases. In particular we analyze effects of background rate variations, gas-density changes, variations of the gas composition, autocalibration, magnetic field differences and non-concentricity of the wire. Their impact on the reconstructed muon momentum resolution was simulated with DICE/ATRECON.The different properties of linear and non-linear drift gases and their relative advantages and disadvantages are discussed in detail.

  10. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Science.gov (United States)

    2010-07-01

    ..., 6-hour precipitation event. (b) Rock-core chimney drains. A rock-core chimney drain may be used in a... as the fill is not located in an area containing intermittent or perennial streams. A rock-core... upstream drainage is diverted around the fill. The alternative rock-core chimney drain system shall...

  11. Filling defect artefacts in magnetic resonance urography

    Energy Technology Data Exchange (ETDEWEB)

    Girish, G.; Chooi, W.K.; Morcos, S.K. [Department of Diagnostic Imaging, Northern General Hospital, Sheffield Teaching Hospitals NHS Trust, S5 7AU, Sheffield (United Kingdom)

    2004-01-01

    The aim of this study was to determine the prevalence of filling defect artefacts (FDA) in magnetic resonance urography (MRU). Retrospectively, we assessed MRU examinations of 45 patients with neurogenic bladder dysfunction (21 men, 24 women; mean age 35 years, age range 18-71 years). The MRU was performed 30 min after intramuscular injection of 20 mg frusemide using heavily T2-weighted fast-spin-echo techniques [axial, thick coronal slab, coronal maximum intensity projection (MIP) images] with fat saturation. The images were reviewed by two observers to determine the presence of filling defects and dilatation of pelvicalyceal system and ureters. The filling defects were classified into central, eccentric and complete. Clinical course and plain films were reviewed to determine significance of the detected filling defects. True filling defects were observed in 5 patients (11%) and all due to stones seen on the plain radiograph of the abdomen. Filling defects artefacts (FDAs) were seen in 23 patients (51%; 17 pelvicalyceal system, 17 upper third of ureters, 7 mid ureters and 1 distal ureter). No stones were seen on the plain radiograph of these patients and they had a favourable clinical course for over 24 months. The true filling defects were large in size, eccentric in position and seen in more than one sequence of the MRU examination (axial, n=5; slab, n=5; and MIP, n=4). Four (80%) of the patients with true defects and 21 (91%) of those with FDAs had dilatation of the pelvicalyceal system and ureters. The FDAs were small in size, centrally placed (74%) and always seen in axial images, rarely in slab images (2 cases) and not seen in MIP images. Artefactual filling defects can be seen in MRU examinations. The cause of the FDAs is not fully explained and could be secondary to turbulent and fast flow of the urine. Some of the FDAs seen in the calyces could be due to the tips of the papillae. Awareness of such defects obviates misinterpretation and prevents

  12. Creep of granulated loose-fill insulation

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    This report presents a proposal for a standardised method for creep tests and the necessary theoretical framework that can be used to describe creep of a granulated loose-fill material. Furthermore results from a round robin test are shown. The round robin test was carried out in collaboration...... with SP-Building Physics in Sweden and VTT Building Technology in Finland. For the round robin test a cellulosic fibre insulation material was used. The proposed standardised method for creep tests and theories are limited to cases when the granulated loose-fill material is exposed to a constant...

  13. Experimental study on capillary filling in nanochannels

    Science.gov (United States)

    Yang, Min; Cao, Bing-Yang; Wang, Wei; Yun, He-Ming; Chen, Bao-Ming

    2016-10-01

    We investigated the capillary filling kinetics of deionized water in nanochannels with heights of 50-120 nm. The measured position of the moving meniscus was proportional to the square root of time, as predicted by the LW equation. However, the extracted slopes were significantly smaller than the predictions based on the bulk properties. This unusual behavior was found to be mainly caused by the electro-viscous effect and dynamic contact angle, which was significantly larger than the static angle. In addition, when the filling distance reached about 600 μm, bubbles tended to be formed, leading to the main meniscus was almost immobile.

  14. Measurement of 37Ar to support technology for On-Site Inspection under the Comprehensive Nuclear-Test-BanTreaty

    Science.gov (United States)

    Aalseth, C. E.; Day, A. R.; Haas, D. A.; Hoppe, E. W.; Hyronimus, B. J.; Keillor, M. E.; Mace, E. K.; Orrell, J. L.; Seifert, A.; Woods, V. T.

    2011-10-01

    On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced by neutron interaction with calcium in soil, 40Ca( n, α) 37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45 mBq/SCM in wholeair.

  15. Measurement of 37Ar to support technology for On-site Inspection under the Comprehensive Nuclear-Test-Ban Treaty

    CERN Document Server

    Aalseth, C E; Haas, D A; Hoppe, E W; Hyronimus, B J; Keillor, M E; Mace, E K; Orrell, J L; Seifert, A; Woods, V T

    2010-01-01

    On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced from neutron interaction with calcium in soil, 40Ca(n,{\\alpha})37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45.1 mBq/SCM in whole air.

  16. Realistic Models for Filling Factors in HII Regions

    Science.gov (United States)

    Spangler, Steven R.; Costa, Allison H.; Bergerud, Brandon M.; Beauchamp, Kara M.

    2017-01-01

    One of the parameters used to describe HII regions and other ionized parts of the interstellar medium is the filling factor, defined as the volume fraction of an HII region occupied by matter. The best observational evidence for the existence of a filling factor less than unity is a discrepancy between the electron density derived from density-sensitive line ratios and the root mean square density obtained from emission measure measurements. Following the early, influential study by Osterbrock and Flather (ApJ 129, 26, 1959), most investigations of HII regions envision these objects as a group of isolated cells of high gas density embedded in a vacuum. This picture is at serious odds with more direct measurements of other astrophysical plasmas like the solar wind, where the density follows a less extreme probability distribution function (pdf) such as an exponential or lognormal. We have carried out a set of simulations in which model HII regions are created with different density pdfs such as exponential and lognormal as well as the extreme case of two delta functions. We calculate the electron density as inferred from spectroscopic line ratios and emission measures for all lines of sight through the model nebulas. In the cases of exponential and lognormal pdfs, the spectroscopically derived densities are higher than those obtained by the emission measures by factors of 20 to 100 percent. These are considerably smaller than values often reported in the literature, which can be an order of magnitude or greater. We will discuss possible ways to reconcile realistic density pdfs such as measured in space and laboratory plasmas with the results from astronomical spectroscopic measurements. Finally, we point out that for the Orion Nebula, the density discrepancy is due to geometry, not filling factor (O'Dell, ARAA 39, 99, 2001).

  17. The structure of filled skutterudites and the local vibration behavior of the filling atom

    Science.gov (United States)

    Zhou, Xiaojuan; Zong, Peng-an; Chen, Xihong; Tao, Juzhou; Lin, He

    2017-02-01

    Both of atomic pair distribution function (PDF) and extended x-ray absorption fine structure (EXAFS) experiments have been carried out on unfilled and Yb-filled skutterudites YbxCo4Sb12 (x=0, 0.15, 0.2 and 0.25) samples. The structure refinements on PDF data confirm the large amplitude vibration of Yb atom and the dependence of Yb vibration amplitude on the filling content. Temperature dependent EXAFS experiment on filled skutterudites have been carried out at Yb LⅢ-edge in order to explore the local vibration behavior of filled atom. EXAFS experiments show that the Einstein temperature of the filled atom is very low (70.9 K) which agrees with the rattling behavior.

  18. 40Ar-39Ar age of carbonatite-alkaline magmatism in Sung Valley, Maghalaya, India

    Indian Academy of Sciences (India)

    Jyotiranjan S Ray; Kanchan Pande

    2001-09-01

    40Ar-39Ar analyses of one alkali pyroxenite whole rock and two phlogopite separates of calcite carbonatites from the Sung Valley carbonatite-alkaline complex, which is believed to be a part of the Rajmahal-Bengal-Sylhet (RBS) ood basalt province, yielded indistinguishable plateau ages of 108.8 ± 2.0 Ma, 106:4 ± 1.3 Ma and 107.5 ± 1.4 Ma, respectively. The weighted mean of these ages, 107.2 ± 0.8 Ma, is the time of emplacement of this complex. This implies that Sung Valley complex and probably other such complexes in the Assam-Meghalaya Plateau postdate the main ood basalt event (i.e., the eruption of tholeiites) in the RBS province by ∼10 Ma.

  19. 40Ar/39Ar dates from the West Siberian Basin: Siberian flood basalt province doubled.

    Science.gov (United States)

    Reichow, Marc K; Saunders, Andrew D; White, Rosalind V; Pringle, Malcolm S; Al'Mukhamedov, Alexander I; Medvedev, Alexander I; Kirda, Nikolay P

    2002-06-07

    Widespread basaltic volcanism occurred in the region of the West Siberian Basin in central Russia during Permo-Triassic times. New 40Ar/39Ar age determinations on plagioclase grains from deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago. This is synchronous with the bulk of the Siberian Traps, erupted further east on the Siberian Platform. The age and geochemical data confirm that the West Siberian Basin basalts are part of the Siberian Traps and at least double the confirmed area of the volcanic province as a whole. The larger area of volcanism strengthens the link between the volcanism and the end-Permian mass extinction.

  20. Cooling age of Dabie orogen, China, determined by 40Ar-39Ar and fission track techniques

    Institute of Scientific and Technical Information of China (English)

    陈江峰; 谢智; 刘顺生; 李学明; K.A.Foland

    1995-01-01

    Based on 40Ar-39Ar results of hornblendes and biotites and fission track dating results of apatites separated from the same rock samples, cooling history of rocks from Dabie orogen is discussed. Rocks from both Southern Dabie Terrain (SDT) and Northern Dabie Terrain (NDT) have an early fast cooling followed by a more recent slow cooling. Rocks from SDT cooled to about 540℃ at about 190 Ma B.C., while rocks from NDT cooled to about 540℃ at 125 Ma B C. Until about 110-120 Ma B.C., rocks from both SDT and NDT cooled to about 100℃. This suggests that a relative movement among rocks from SDT, NDT and ul-Ira-high pressure metamorphic rocks exis-ts before 110-120 Ma B.C.

  1. Laser step-heating 40Ar/39Ar dating on young volcanic rocks

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; HE Huaiyu; ZHU Rixiang; YANG Liekun; SANG Haiqing; WANG Yinglan

    2006-01-01

    An attempt was made to use CO2 laser step-heating method to date the late Pleistocene basaltic groundmass (DF-2) from Tengchong volcanic field. Among the fourteen heating steps, ten define a good inverse isochron (MSWD = 1.4) with an age of 32.2 ± 7.1 ka (2 σ).The inverse isochron also shows that the initial argon isotopic ratio is 297.1±2.0 (2σ)which is the same as the atmospheric argon at the 2σ error level. Study indicates that it is a useful means to date young volcanic groundmass with low K content by using CO2 laser step-heating 40Ar/39Ar method.

  2. Pulsed electrical breakdown of a void-filled dielectric

    Science.gov (United States)

    Anderson, R. A.; Lagasse, R. R.; Schroeder, J. L.

    2002-05-01

    We report breakdown strengths in a void-filled dielectric material, epoxy containing 48 vol % hollow glass microballoon filler, which is stressed with unipolar voltage pulses of the order of 10 μs duration. The microballoon voids had mean diameters of approximately 40 μm and contained SO2 gas at roughly 30% atmospheric pressure. This void-filled material displays good dielectric strength (of the order of 100 kV mm-1) under these short-pulse test conditions. Results from a variety of electrode geometries are reported, including arrangements in which the electric stress is highly nonuniform. Conventional breakdown criteria based on mean or peak electric stress do not account for these data. A statistics-based predictive breakdown model is developed, in which the dielectric is divided into independent, microballoon-sized "discharge cells" and the spontaneous discharge of a single cell is presumed to launch full breakdown of the composite. We obtain two empirical parameters, the mean and standard deviation of the spontaneous discharge field, by fitting breakdown data from two electrode geometries having roughly uniform fields but with greatly differing volumes of electrically stressed material. This model accounts for many aspects of our data, including the inherent statistical scatter and the dependence on the stressed volume, and it provides informative predictions with electrode geometries giving highly nonuniform fields. Issues related to computational spatial resolution and cutoff distance are also discussed.

  3. Spatial autocorrelation method using AR model; Kukan jiko sokanho eno AR model no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H.; Obuchi, T.; Saito, T. [Iwate University, Iwate (Japan). Faculty of Engineering

    1996-05-01

    Examination was made about the applicability of the AR model to the spatial autocorrelation (SAC) method, which analyzes the surface wave phase velocity in a microtremor, for the estimation of the underground structure. In this examination, microtremor data recorded in Morioka City, Iwate Prefecture, was used. In the SAC method, a spatial autocorrelation function with the frequency as a variable is determined from microtremor data observed by circular arrays. Then, the Bessel function is adapted to the spatial autocorrelation coefficient with the distance between seismographs as a variable for the determination of the phase velocity. The result of the AR model application in this study and the results of the conventional BPF and FFT method were compared. It was then found that the phase velocities obtained by the BPF and FFT methods were more dispersed than the same obtained by the AR model. The dispersion in the BPF method is attributed to the bandwidth used in the band-pass filter and, in the FFT method, to the impact of the bandwidth on the smoothing of the cross spectrum. 2 refs., 7 figs.

  4. Study of Nozzle and Vent Locations on Die Casting Filling Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The casting nozzle location plays an important role in die casting. Improper location results in defects, such as cold shut, air cavity, shrinkage, etc. Therefore, it's sure that the molten metal full fills the mould cavity before it solidifies. And, it's to be wished that no vortex occur during the filling process, because the vortex is a main source that induces gas entrapment. To get the high quality and performance product, the inlet and outlet locations must be set properly. This paper, an optimal desi...

  5. Coupled discrete element and smoothed particle hydrodynamics simulations of the die filling process

    Science.gov (United States)

    Breinlinger, Thomas; Kraft, Torsten

    2016-11-01

    Die filling is an important part of the powder compaction process chain, where defects in the final part can be introduced—or prevented. Simulation of this process is therefore a goal for many part producers and has been studied by some researchers already. In this work, we focus on the influence of the surrounding air on the powder flow. We demonstrate the implementing and coupling of the discrete element method for the granular powder and the smoothed particle hydrodynamics method for the gas flow. Application of the method to the die filling process is demonstrated.

  6. Cavity air flow behavior during filling in microinjection molding

    DEFF Research Database (Denmark)

    Griffiths, C.A.; Dimov, S.S.; Scholz, S.

    2011-01-01

    Process monitoring of microinjection molding (μ-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency with regard to parts' quality. Quality factors related to mold cavity air evacuation can provide...... valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental setup is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a microelectromechanical system gas sensor...... mounted inside the mold. The influence of four μIM parameters, melt temperature, mold temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidences about...

  7. The Chemistry of Modern Dental Filling Materials.

    Science.gov (United States)

    Nicholson, John W.; Anstice, H. Mary

    1999-01-01

    Discusses materials used by dentists to restore teeth after decay has been removed. Shows how dental-material science is an interdisciplinary field in which chemistry plays a major part. Reviews the many developments polymer chemistry has contributed to the field of dental fillings. (CCM)

  8. Electroviscous effects in capillary filling of nanochannels

    DEFF Research Database (Denmark)

    Mortensen, Asger; Kristensen, Anders

    2008-01-01

    We theoretically examine the widespread hypothesis of an electroviscous origin of the increase in apparent viscosity observed in recent experiments on capillary filling of nanochannels. Including Debye-layer corrections to the hydraulic resistance, we find that the apparent viscosity reaches a ma...

  9. Modelling of the Manifold Filling Dynamics

    DEFF Research Database (Denmark)

    Hendricks, Elbert; Chevalier, Alain Marie Roger; Jensen, Michael

    1996-01-01

    Mean Value Engine Models (MVEMs) are dynamic models which describe dynamic engine variable (or state) responses on time scales slightly longer than an engine event. This paper describes a new model of the intake manifold filling dynamics which is simple and easy to calibrate for use in engine con...

  10. Topological scaling and gap filling at crisis

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, K. Gabor [Department of Mathematics, University of Kansas, Lawrence, Kansas 66045 (United States); Institute for Theoretical Physics, Eoetvoes University, P.O. Box 32, Budapest, H-1518, (Hungary); Lai, Ying-Cheng [Department of Mathematics and Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Tel, Tamas [Institute for Theoretical Physics, Eoetvoes University, P.O. Box 32, Budapest, H-1518, (Hungary); Grebogi, Celso [Institute for Plasma Research, Department of Mathematics, and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States)

    2000-05-01

    Scaling laws associated with an interior crisis of chaotic dynamical systems are studied. We argue that open gaps of the chaotic set become densely filled at the crisis due to the sudden appearance of unstable periodic orbits with extremely long periods. We formulate a scaling theory for the associated growth of the topological entropy. (c) 2000 The American Physical Society.

  11. Safety distances for hydrogen filling stations

    NARCIS (Netherlands)

    Matthijsen, A J C M; Kooi, E S

    2006-01-01

    In the context of spatial planning the Dutch Ministry of Housing, Spatial Planning and the Environment asked the Centre for External Safety of the National Institute for Public Health and the Environment (RIVM) to advice on safe distances pertaining to hydrogen filling stations. The RIVM made use of

  12. Irregularly Shaped Space-Filling Truncated Octahedra

    Science.gov (United States)

    Hanson, John Robert

    2008-01-01

    For any parent tetrahedron ABCD, centroids of selected sub-tetrahedra form the vertices of an irregularly shaped space-filling truncated octahedron. To reflect these properties, such a figure will be called an ISTO. Each edge of the ISTO is parallel to and one-eighth the length of one of the edges of tetrahedron ABCD and the volume of the ISTO is…

  13. Root canal filling using Resilon: a review.

    LENUS (Irish Health Repository)

    Shanahan, D J

    2011-07-01

    Root canal treatment is achieved by chemo-mechanical debridement of the root canal system followed by filling. The filling material \\'entombs\\' residual bacteria and acts as a barrier which prevents the entrance of oral microorganisms and reinfection of the root canal system through microleakage. However, filling with contemporary root filling materials such as gutta-percha offers limited long-term resistance to microorganisms; as a result other materials such as Resilon have been investigated as alternatives. The aim of this review was to analyse the literature to consider whether Resilon is a suitable root canal filling material. A MEDLINE and Cochrane library search including various keyword searches identified several papers which investigated or discussed Resilon or RealSeal\\/Epiphany. Analysis of the literature demonstrated that the bulk of the literature is in vitro in nature, based largely on leakage-type studies, and demonstrates a wide variety of methodologies with conflicting findings; as a result meaningful conclusions are difficult. Within the limit of these in vitro studies Resilon appears to perform adequately in comparison to gutta-percha, however, as a result of the questionable merit of such studies, it cannot presently be considered an evidence-based alternative to the current gold standard gutta-percha. It is imperative that before Resilon is considered as a replacement material, a better understanding of the physical properties of the resin sealer and the reality of the adhesive \\'monoblock\\' are elucidated. The literature also demonstrates a paucity of quality long-term clinical outcome studies which will need to be addressed before firm conclusions can be reached.

  14. Regulation of AR Degradation and Function by Ubiquitylation

    Science.gov (United States)

    2014-10-01

    Identify ubiquitylation sites associated with degradation of the unliganded AR. We have used liquid chromatography followed by tandem mass spectrometry (LC...unmodified AR band in another gel slice). Protein in gel slices was then digested with trypsin (which leaves a gly-gly tag on ubiquitin-modified proteins

  15. Aspects of What Makes or Breaks a Museum AR Experience

    DEFF Research Database (Denmark)

    Madsen, Claus B.; Madsen, Jacob Boesen; Morrison, Ann

    2012-01-01

    The paper critically evaluates central aspects of an iPad AR application developed for a museum context. The application is designed for children aged 8 to 12 and mixes AR and mini-game elements to convey dramatized historical events. The game has been deployed for roughly 3 months and the findin...

  16. 75 FR 12163 - Class E Airspace; Mountain View, AR

    Science.gov (United States)

    2010-03-15

    ... Federal Aviation Administration 14 CFR Part 71 Class E Airspace; Mountain View, AR AGENCY: Federal... proposes to amend Class E airspace at Mountain View, AR. Decommissioning of the Wilcox non-directional beacon (NDB) at Mountain View Wilcox Memorial Field Airport has made this action necessary for the...

  17. 7 CFR 52.774 - Fill of container.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fill of container. 52.774 Section 52.774 Agriculture... United States Standards for Grades of Canned Red Tart Pitted Cherries 1 Fill of Container § 52.774 Fill of container. (a) FDA requirements. Canned red tart pitted cherries shall meet the fill of...

  18. A Defence of the AR4’s Bayesian Approach to Quantifying Uncertainty

    Science.gov (United States)

    Vezer, M. A.

    2009-12-01

    The field of climate change research is a kimberlite pipe filled with philosophic diamonds waiting to be mined and analyzed by philosophers. Within the scientific literature on climate change, there is much philosophical dialogue regarding the methods and implications of climate studies. To this date, however, discourse regarding the philosophy of climate science has been confined predominately to scientific - rather than philosophical - investigations. In this paper, I hope to bring one such issue to the surface for explicit philosophical analysis: The purpose of this paper is to address a philosophical debate pertaining to the expressions of uncertainty in the International Panel on Climate Change (IPCC) Fourth Assessment Report (AR4), which, as will be noted, has received significant attention in scientific journals and books, as well as sporadic glances from the popular press. My thesis is that the AR4’s Bayesian method of uncertainty analysis and uncertainty expression is justifiable on pragmatic grounds: it overcomes problems associated with vagueness, thereby facilitating communication between scientists and policy makers such that the latter can formulate decision analyses in response to the views of the former. Further, I argue that the most pronounced criticisms against the AR4’s Bayesian approach, which are outlined below, are misguided. §1 Introduction Central to AR4 is a list of terms related to uncertainty that in colloquial conversations would be considered vague. The IPCC attempts to reduce the vagueness of its expressions of uncertainty by calibrating uncertainty terms with numerical probability values derived from a subjective Bayesian methodology. This style of analysis and expression has stimulated some controversy, as critics reject as inappropriate and even misleading the association of uncertainty terms with Bayesian probabilities. [...] The format of the paper is as follows. The investigation begins (§2) with an explanation of

  19. AR Sco: A White Dwarf Synchronar

    CERN Document Server

    Katz, J I

    2016-01-01

    The emission of the white dwarf-M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. This requires a comparatively large magnetic field $\\sim 100$ gauss at the M dwarf and $\\sim 10^8$ gauss on the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf's magnetic field sweeps past the M dwarf or by a misaligned white dwarf's rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.

  20. AR Sco: A Precessing White Dwarf Synchronar?

    Science.gov (United States)

    Katz, J. I.

    2017-02-01

    The emission of the white dwarf–M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. Synchronization requires a magnetic field ∼100 Gauss at the M dwarf and ∼ {10}8 Gauss at the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf, within the near zone of the rotating white dwarf’s field, by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf’s magnetic field sweeps past the M dwarf or by a misaligned white dwarf rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of the optical maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.