WorldWideScience

Sample records for expansion chambers

  1. Changes of pulp-chamber dimensions 1 year after rapid maxillary expansion.

    Science.gov (United States)

    Baratieri, Carolina; Alves, Matheus; Mattos, Cláudia Trindade; Souza, Margareth Maria Gomes de; Ruellas, Antônio Carlos de Oliveira

    2013-04-01

    The purpose of this study was to examine the effect of orthopedic forces on maxillary first molars' and maxillary central incisors' pulp chambers in children having rapid maxillary expansion as the only intervention compared with children having no orthodontic intervention by using cone-beam computed tomography images. In this prospective controlled clinical study, we evaluated 60 maxillary first molars and 60 maxillary central incisors from 30 children (18 boys, 12 girls) in the mixed dentition and during the pubertal growth period. The treated group had rapid maxillary expansion with the Haas expander, followed by 6 months of retention and 6 months of follow-up out of retention; the control group had no intervention during the study. Cone-beam computed tomography scans were taken initially and 1 year after the rapid maxillary expansion active phase. Initially, a 3-dimensional scrolling in all pulp chambers of the evaluated teeth was performed with Dolphin Imaging software (version 11.0; Dolphin Imaging & Management Solutions, Chatsworth, Calif) to describe the incidence of pulp-chamber calcifications. The dimensions of the pulp chambers of the molars and incisors were also investigated. Cross-sectional and longitudinal slices were used for each molar (coronal and axial slices) and incisor (sagittal and axial slices). The area (mm(2)) was obtained from 3 slices of each kind (6 measurements for each tooth). The results suggest that rapid maxillary expansion did not induce new pulp-chamber calcification. Also, it did not interfere in normal pulp-chamber dimension changes of the anchorage molars. The pulp chamber of the central incisors can be expected to be minimally wider 1 year after the therapy. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  2. Reduction of Discrete-Frequency Fan Noise Using Slitlike Expansion Chambers

    Directory of Open Access Journals (Sweden)

    Akira Sadamoto

    2003-01-01

    Full Text Available As is generally known, discrete-frequency noises are radiated from fans due to rotor-stator interaction. Their fundamental frequency is the blade-passage frequency, which is determined by the number of rotor blades and their rotating speeds. To reduce such noises, several types of silencers have been designed. Among them, the authors noted a slitlike expansion chamber (hereafter referred to as slit, for simplicity and have studied its performance. A slit is a simple expansion chamber with a very short axial length that is placed in a duct. A slit with a circular cross-section that is concentric with a circular duct may be studied using the same interpretation as is used for a side-branch resonator muffler (closed-end tube connected to a duct; that is, the resonant frequency of a slit depends on its depth (with an open-end correction. It is expected, hence, that a slit might be applicable as a simple and axially compact silencer that is effective on discrete-frequency noises. In this article, the properties of a slit are introduced, and the applicability of a slit to actual rotating machinery is described using experimental data.

  3. Phase transition observations and discrimination of small cloud particles by light polarization in expansion chamber experiments

    Directory of Open Access Journals (Sweden)

    L. Nichman

    2016-03-01

    Full Text Available Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD chamber facility at the European Organization for Nuclear Research (CERN to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary organic aerosol (SOA are presented. We report observations of significant liquid–viscous SOA particle polarization transitions under dry conditions using CASPOL. Cluster analysis techniques were subsequently used to classify different types of particles according to their polarization ratios during phase transition. A classification map is presented for water droplets, organic aerosol (e.g., SOA and oxalic acid, crystalline substances such as ammonium sulfate, and volcanic ash. Finally, we discuss the benefits and limitations of this classification approach for atmospherically relevant concentrations and mixtures with respect to the CLOUD 8–9 campaigns and its potential contribution to tropical troposphere layer analysis.

  4. submitter Phase transition observations and discrimination of small cloud particles by light polarization in expansion chamber experiments

    CERN Document Server

    Nichman, Leonid; Järvinen, Emma; Ignatius, Karoliina; Höppel, Niko Florian; Dias, Antonio; Heinritzi, Martin; Simon, Mario; Tröstl, Jasmin; Wagner, Andrea Christine; Wagner, Robert; Williamson, Christina; Yan, Chao; Connolly, Paul James; Dorsey, James Robert; Duplissy, Jonathan; Ehrhart, Sebastian; Frege, Carla; Gordon, Hamish; Hoyle, Christopher Robert; Kristensen, Thomas Bjerring; Steiner, Gerhard; McPherson Donahue, Neil; Flagan, Richard; Gallagher, Martin William; Kirkby, Jasper; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Stratmann, Frank; Tomé, António

    2016-01-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD) chamber facility at the European Organization for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary ...

  5. BEBC bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  6. Heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  7. Test chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    A test chamber for measuring electromagnetic radiation emitted by an apparatus to be tested or for exposing an apparatus to be tested to an electromagnetic radiation field. The test chamber includes a reverberation chamber made of a conductive tent fabric. To create a statistically uniform field in

  8. Test chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    1999-01-01

    A test chamber for measuring electromagnetic radiation emitted by an apparatus to be tested or for exposing an apparatus to be tested to an electromagnetic radiation field. The test chamber includes a reverberation chamber made of a conductive tent fabric. To create a statistically uniform field in

  9. Ussing Chamber

    NARCIS (Netherlands)

    Westerhout, J.; Wortelboer, H.; Verhoeckx, K.

    2015-01-01

    The Ussing chamber system is named after the Danish zoologist Hans Ussing, who invented the device in the 1950s to measure the short-circuit current as an indicator of net ion transport taking place across frog skin (Ussing and Zerahn, Acta Physiol Scand 23:110-127, 1951). Ussing chambers are

  10. wire chamber

    CERN Multimedia

    Proportional multi-wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle. Proportional wire chambers allow a much quicker reading than the optical or magnetoscriptive readout wire chambers.

  11. Wire chamber

    CERN Multimedia

    1967-01-01

    Magnetoscriptive readout wire chamber.Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  12. Wire Chamber

    CERN Multimedia

    Magnetoscriptive readout wire chamber. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  13. wire chamber

    CERN Multimedia

    Was used in ISR (Intersecting Storage Ring) split field magnet experiment. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  14. wire chamber

    CERN Multimedia

    1985-01-01

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  15. wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  16. Wire chamber

    CERN Multimedia

    Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  17. Maxillary Expansion

    OpenAIRE

    Agarwal, Anirudh; Mathur, Rinku

    2010-01-01

    ABSTRACT Maxillary transverse discrepancy usually requires expansion of the palate by a combination of orthopedic and orthodontic tooth movements. Three expansion treatment modalities are used today: rapid maxillary expansion, slow maxillary expansion and surgically assisted maxillary expansion.This article aims to review the maxillary expansion by all the three modalities and a brief on commonly used appliances.

  18. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Parts of the hydraulic expansion system of the Rapid-Cycling Bubble-Chamber (RCBC). RCBC was the largest of 3 rapid-cycling bubble-chambers (the others were LEBC and HOLEBC), used as target- and vertex-detectors within the European Hybrid Spectrometer (EHS) in the SPS North Area (EHN1). RCBC contained 250 l of liquid hydrogen and was located inside a 3 T superconducting magnet. It was designed for 30 expansions/s (100 times faster than BEBC), the system shown here allowed 50 expansions/s. RCBC operated from 1981 to 1983 for experiments NA21, NA22 and NA23 at a rate of 15 expansions/s, clocking up a total of over 4 million. In the rear, at left, is bearded Lucien Veillet; Augustin Didona is at the right. See also 8001009. The installation of the piston assembly in the RCBC chamber body is shown in the Annual Report 1980, p.65.

  19. Doriot Climatic Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers are two, 60-feet long, 11-feet high, 15-feet wide chambers that are owned and operated by NSRDEC. The Doriot Climatic Chambers are among...

  20. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  1. GRCop-84 Development for Combustion Chamber Liners

    Science.gov (United States)

    Ellis, David; Nathal, Michael; Yun, Hee Man; Lerch, Bradley; Greenbauer-Seng, Leslie; Thomas-Ogbuji, Linus; Holmes, Richard

    2000-01-01

    The development, test, and thermophysical & mechanical properties of a GRCop-84 alloy for combustion chamber liners is discussed. Topics discussed include: History of GRCop-84 development, GRCop-84 thermal expansion, thermal conductivity of GRCop-84, yield strength of GRCop-84, GRCop-84 creep lives, GrCop-84 low cycle fatigue (LCF) lives, and hot fire testing of GRCop-84 spool pieces.

  2. Prototype multiwire proportional chamber

    CERN Multimedia

    1975-01-01

    Chambers of this type were initially developed within the Alpha project (finally not approved). They were designed such to minimize the radiation length with a view to a mass spectrometer of high resolution meant to replace the Omega detector. The chambers were clearly forerunners for the (drift) chambers later built for R606 with the novel technique of crimping the wires. See also photo 7510039X.

  3. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  4. Electromagnetic reverberation chambers

    CERN Document Server

    Besnier, Philippe

    2013-01-01

    Dedicated to a complete presentation on all aspects of reverberation chambers, this book provides the physical principles behind these test systems in a very progressive manner. The detailed panorama of parameters governing the operation of electromagnetic reverberation chambers details various applications such as radiated immunity, emissivity, and shielding efficiency experiments.In addition, the reader is provided with the elements of electromagnetic theory and statistics required to take full advantage of the basic operational rules of reverberation chambers, including calibration proc

  5. Refrigeration Test Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The enclosed and environmentally controlled chamber is able to test four units (single-phase) simultaneously at conditions ranging from tundra to desert temperatures...

  6. DORIOT CLIMATIC CHAMBERS

    Data.gov (United States)

    Federal Laboratory Consortium — The Doriot Climatic Chambers reproduce environmental conditions occurring anywhere around the world. They provide an invaluable service by significantly reducing the...

  7. expansion method

    Indian Academy of Sciences (India)

    In this paper, we shall apply the (G /G)-expansion method to obtain the exact travelling wave solution of the two-dimensional ... In §3, we apply our method to the mentioned equations. In §4, some conclusions are ..... The exact solution obtained by this method can be used to check computer codes or as initial condition for ...

  8. The Mobile Chamber

    Science.gov (United States)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  9. DELPHI time projection chamber

    CERN Multimedia

    1989-01-01

    The time projection chamber is inserted inside the central detector of the DELPHI experiment. Gas is ionised in the chamber as a charged particle passes through, producing an electric signal from which the path of the particle can be found. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  10. Climatic chamber ergometer

    CSIR Research Space (South Africa)

    Atkins, AR

    1968-01-01

    Full Text Available The design and calibration of an ergometer for exercising subjects during calorimetric studies in the climate chamber, are described. The ergometer is built into the climatic chamber and forms an integral part of the whole instrumentation system foe...

  11. PS wire chamber

    CERN Multimedia

    1970-01-01

    A wire chamber used at CERN's Proton Synchrotron accelerator in the 1970s. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  12. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  13. Obelix Wire Chamber

    CERN Multimedia

    1986-01-01

    Two wire chambers made originally for the R807 Experiment at CERN's Intersecting Storage Rings. In 1986 they were used for the PS 201 experiment (Obelix Experiment) at LEAR, the Low Energy Antiproton Ring. The group of researchers from Turin, using the chambers at that time, changed the acquisition system using for the first time 8 bit (10 bit non linear) analog to digital conversion for incoming signals from the chambers. The acquisition system was controlled by 54 CPU and 80 digital signal processors. The power required for all the electronics was 40 kW. For the period, this system was one of the most powerful on-line apparatus in the world. The Obelix Experiment was closed in 1996. To find more about how a wire chamber works, see the description for object CERN-OBJ-DE-038.

  14. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  15. Time expansion chambers of the ALICE Transition Radiation Detector (TRD)

    CERN Multimedia

    2003-01-01

    The TRD is segmented into 18 sectors in the azimuthal angle. Each sector consists of 6 layers in the radial direction and is composed of 5 stacks in the longitudinal direction. This amounts to 540 individual detector modules with a total active area of roughly 750 m2 and 1.2 million readout channels. The largest module is 159 cm long and 120 cm wide.

  16. Target Chamber Manipulator

    Science.gov (United States)

    Tantillo, Anthony; Watson, Matthew

    2015-11-01

    A system has been developed to allow remote actuation of sensors in a high vacuum target chamber used with a particle accelerator. Typically, sensors of various types are placed into the target chamber at specific radial and angular positions relative to the beam line and target. The chamber is then evacuated and the experiments are performed for those sensor positions. Then, the chamber is opened, the sensors are repositioned to new angles or radii, and the process is repeated, with a separate pump-down cycle for each set of sensor positions. The new sensor positioning system allows scientists to pre-set the radii of up to a dozen sensors, and then remotely actuate their angular positions without breaking the vacuum of the target chamber. This reduces the time required to reposition sensors from 6 hours to 1 minute. The sensors are placed into one of two tracks that are separately actuated using vacuum-grade stepping motors. The positions of the sensors are verified using absolute optical rotary encoders, and the positions are accurate to 0.5 degrees. The positions of the sensors are electronically recorded and time-stamped after every change. User control is through a GUI using LabVIEW.

  17. The KLOE drift chamber

    CERN Document Server

    Adinolfi, M; Ambrosino, F; Andryakov, A; Antonelli, A; Antonelli, M; Anulli, F; Bacci, C; Bankamp, A; Barbiellini, G; Bellini, F; Bencivenni, G; Bertolucci, Sergio; Bini, C; Bloise, C; Bocci, V; Bossi, F; Branchini, P; Bulychjov, S A; Cabibbo, G; Calcaterra, A; Caloi, R; Campana, P; Capon, G; Carboni, G; Cardini, A; Casarsa, M; Cataldi, G; Ceradini, F; Cervelli, F; Cevenini, F; Chiefari, G; Ciambrone, P; Conetti, S; Conticelli, S; Lucia, E D; Robertis, G D; Sangro, R D; Simone, P D; Zorzi, G D; Dell'Agnello, S; Denig, A; Domenico, A D; Donato, C D; Falco, S D; Doria, A; Drago, E; Elia, V; Erriquez, O; Farilla, A; Felici, G; Ferrari, A; Ferrer, M L; Finocchiaro, G; Forti, C; Franceschi, A; Franzini, P; Gao, M L; Gatti, C; Gauzzi, P; Giovannella, S; Golovatyuk, V; Gorini, E; Grancagnolo, F; Grandegger, W; Graziani, E; Guarnaccia, P; Von Hagel, U; Han, H G; Han, S W; Huang, X; Incagli, M; Ingrosso, L; Jang, Y Y; Kim, W; Kluge, W; Kulikov, V; Lacava, F; Lanfranchi, G; Lee-Franzini, J; Lomtadze, F; Luisi, C; Mao Chen Sheng; Martemyanov, M; Matsyuk, M; Mei, W; Merola, L; Messi, R; Miscetti, S; Moalem, A; Moccia, S; Moulson, M; Müller, S; Murtas, F; Napolitano, M; Nedosekin, A; Panareo, M; Pacciani, L; Pagès, P; Palutan, M; Paoluzi, L; Pasqualucci, E; Passalacqua, L; Passaseo, M; Passeri, A; Patera, V; Petrolo, E; Petrucci, Guido; Picca, D; Pirozzi, G; Pistillo, C; Pollack, M; Pontecorvo, L; Primavera, M; Ruggieri, F; Santangelo, P; Santovetti, E; Saracino, G; Schamberger, R D; Schwick, C; Sciascia, B; Sciubba, A; Scuri, F; Sfiligoi, I; Shan, J; Silano, P; Spadaro, T; Spagnolo, S; Spiriti, E; Stanescu, C; Tong, G L; Tortora, L; Valente, E; Valente, P; Valeriani, B; Venanzoni, G; Veneziano, Stefano; Wu, Y; Xie, Y G; Zhao, P P; Zhou, Y

    2001-01-01

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy K sub L produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm sup 2 in size in the 12 innermost layers and 3x3 cm sup 2 in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented.

  18. DELPHI Barrel Muon Chamber Module

    CERN Multimedia

    1989-01-01

    The module was used as part of the muon identification system on the barrel of the DELPHI detector at LEP, and was in active use from 1989 to 2000. The module consists of 7 individual muons chambers arranged in 2 layers. Chambers in the upper layer are staggered by half a chamber width with respect to the lower layer. Each individual chamber is a drift chamber consisting of an anode wire, 47 microns in diameter, and a wrapped copper delay line. Each chamber provided 3 signal for each muon passing through the chamber, from which a 3D space-point could be reconstructed.

  19. Charpak hemispherical wire chamber

    CERN Multimedia

    1970-01-01

    pieces. Mesures are of the largest one. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  20. 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.

  1. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  2. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  3. Rocket Combustion Chamber Coating

    Science.gov (United States)

    Holmes, Richard R. (Inventor); McKechnie, Timothy N. (Inventor)

    2001-01-01

    A coating with the ability to protect (1) the inside wall (i.e., lining) of a rocket engine combustion chamber and (2) parts of other apparatuses that utilize or are exposed to combustive or high temperature environments. The novelty of this invention lies in the manner a protective coating is embedded into the lining.

  4. Chamber Profile Measurement System.

    Science.gov (United States)

    1980-10-01

    travel with the proper electronics. Other features of tihe gage assembly are: 1. Micrometer controlled down chamber positioning of the master template to...pressure sensitive "stiff stick" for infinitely varying the rate of travel from zero to maximum. A manual vernier control is incorporated to permit fine

  5. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  6. Multiwire proportional chamber development

    Science.gov (United States)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  7. Anechoic Radio Frequency Test Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — This chamber is used for characterization test of such systems as communications gear, tanks, radar, missiles, and helicopters. The dimensions of the chamber are 114...

  8. Computational investigation of the temperature separation in vortex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Anish, S. [National Institute of Technology Karnataka, Mangalore (India); Setoguchi, T. [Institute of Ocean Energy, Saga University (Japan); Kim, H. D. [Andong National University, Andong (Korea, Republic of)

    2014-06-15

    The vortex chamber is a mechanical device, without any moving parts that separates compressed gas into a high temperature region and a low temperature region. Functionally vortex chamber is similar to a Ranque-Hilsch vortex tube (RVHT), but it is a simpler and compact structure. The objective of the present study is to investigate computationally the physical reasoning behind the energy separation mechanism inside a vortex chamber. A computational analysis has been performed using three-dimensional compressible Navier Stokes equations. A fully implicit finite volume scheme was used to solve the governing equations. A commercial software ANSYS CFX is used for this purpose. The computational predictions were validated with existing experimental data. The results obtained show that the vortex chamber contains a large free vortex zone and a comparatively smaller forced vortex region. The physical mechanism that causes the heating towards periphery of the vortex chamber is identified as the work done by the viscous force. The cooling at the center may be due to expansion of the flow. The extent of temperature separation greatly depends on the outer diameter of the vortex chamber. A small amount of compression is observed towards the periphery of the vortex chamber when the outer diameter is reduced.

  9. Vacuum Chambers for LEP sections

    CERN Multimedia

    1983-01-01

    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  10. Wire chambers revisited.

    Science.gov (United States)

    Ott, R J

    1993-04-01

    Detectors used for radioisotope imaging have, historically, been based on scintillating crystal/photomultiplier combinations in various forms. From the rectilinear scanner through to modern gamma cameras and positron cameras, the basic technology has remained much the same. Efforts to overcome the limitations of this form of technology have foundered on the inability to reproduce the required sensitivity, spatial resolution and sensitive area at acceptable cost. Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. As gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of "gas only" photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera. The MWPC camera produces quantitative

  11. Review of wire chamber aging

    Energy Technology Data Exchange (ETDEWEB)

    Va' Vra, J.

    1986-02-01

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs.

  12. Posterior chamber pseudophakia.

    Science.gov (United States)

    Simcoe, C W

    1982-01-01

    Anatomically, the most physiological type of implant is that of the posterior chamber of the eye. After a brief historical review of these implants, two models differing by their loops are compared, these being either in the form of a J with narrow extremities or in the form of a C. The latter model possesses definite advantages. Firstly, the point of pressure on the lens capsule is less concentrated, reducing the pressure exerted by the loops and thus avoiding rupture of the zonular ciliaris, Secondly, contact in the form of an are prevents movement of the implant around its axis, a factor favorizing capsule slipping. Thirdly, the improved pressure distribution of the loops resulting from their greater flexibility also prevents the "windscreen wiper syndrome", providing improved stability of the implant. The technique employed avoids all contact taking place with the endothelium. The upper loop is placed in position after closure of the incision. Results in 1532 cases were very positive, and studies are currently being conducted with an implant with four loops in which the optic is within the posterior chamber, and which could be positioned after intracapsular extraction. A system of irrigation-aspiration is described which employs a fine curved canula that is easier to manage and permits improved cleaning of the capsule. Emphasis is placed on the need for narrow, deep, corneal sutures to reduce postoperative astigmatism.

  13. Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    To complete the revamp of CERN’s Council Chamber, a new exhibition is being installed just in time for the June Council meetings.   Panels will showcase highlights of CERN’s history, using some of the content prepared for the exhibitions marking 50 years of the PS, which were displayed in the main building last November. The previous photo exhibition in the Council Chamber stopped at the 1970s. To avoid the new panels becoming quickly out of date, photos are grouped together around specific infrastructures, rather than following a classic time-line. “We have put the focus on the accelerators – the world-class facilities that CERN has been offering researchers over the years, from the well-known large colliders to the lesser-known smaller facilities,” says Emma Sanders, who worked on the content. The new exhibition will be featured in a future issue of the Bulletin with photos and an interview with Fabienne Marcastel, designer of the exhibit...

  14. Michigan ATLAS MDT Chamber Mass Production

    CERN Document Server

    Diehl, E; Levin, D; McKee, S; Neal, H; Schick, H; Tarle, G; Thun, R; Weaverdyck, C; Xu, Q; Zhao, Z; Zhou, B

    2001-01-01

    This paper describes the ATLAS MDT precision muon chamber construction at the University of Michigan. The chamber assembly facilities, the jigging set up, alignment procedures, and other measurements necessary for chamber assembly are described. The chamber quality assurance monitoring procedures and data for the first year mass production are presented. The chamber gas system assembly facilities, and the chamber leak test procedure together with data also reported. The chamber production database, which monitors chamber production, is also discussed.

  15. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  16. The ALICE time projection chamber

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    This time projection chamber is part of the ALICE detector on the new LHC accelerator at CERN. Particles produced in collisions at the core of the detector will follow paths outward through the various sub-detector layers. If these particles carry a charge, they will ionise the gas contained within this chamber producing an electric signal as the ions drift in the chamber's electric field.

  17. Portable electron beam weld chamber

    Science.gov (United States)

    Lewis, J. R.; Dimino, J. M.

    1972-01-01

    Development and characteristics of portable vacuum chamber for skate type electron beam welding are discussed. Construction and operational details of equipment are presented. Illustrations of equipment are provided.

  18. The Big European Bubble Chamber

    CERN Multimedia

    1977-01-01

    The 3.70 metre Big European Bubble Chamber (BEBC), dismantled on 9 August 1984. During operation it was one of the biggest detectors in the world, producing direct visual recordings of particle tracks. 6.3 million photos of interactions were taken with the chamber in the course of its existence.

  19. Characterization of a Reverberation Chamber

    Science.gov (United States)

    2015-10-01

    applied to the same device inside another facility, such as a gigahertz transverse electromagnetic (GTEM) or fully- anechoic chamber for further...and found to be consistent; reflections measured from inside the chamber yielded heavy spiking. The antenna used to transmit power into the room was

  20. Bridges Expansion Joints

    OpenAIRE

    Sergey W. Kozlachkow

    2012-01-01

    The survey is concerned with the expansion joints, used in bridge constructions to compensate medium and significant operational linear and spatial displacements between adjacent spans or between bridge span and pier. The analysis of design features of these types of expansion joints, their advantages and disadvantages, based on operational experience justified the necessity to design constructions, meeting the modern demands imposed to expansion joints.

  1. National Ignition Facility Target Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Wavrik, R W; Cox, J R; Fleming, P J

    2000-10-05

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This

  2. The CLEO III drift chamber

    CERN Document Server

    Peterson, D; Briere, R A; Chen, G; Cronin-Hennessy, D; Csorna, S; Dickson, M; Dombrowski, S V; Ecklund, K M; Lyon, A; Marka, S; Meyer, T O; Patterson, J R; Sadoff, A; Thies, P; Thorndike, E H; Urner, D

    2002-01-01

    The CLEO group at the Cornell Electron Storage Ring has constructed and commissioned a new central drift chamber. With 9796 cells arranged in 47 layers ranging in radius from 13.2 to 79 cm, the new drift chamber has a smaller outer radius and fewer wires than the drift chamber it replaces, but allows the CLEO tracking system to have improved momentum resolution. Reduced scattering material in the chamber gas and in the inner skin separating the drift chamber from the silicon vertex detector provides a reduction of the multiple scattering component of the momentum resolution and an extension of the usable measurement length into the silicon. Momentum resolution is further improved through quality control in wire positioning and symmetry of the electric fields in the drift cells which have provided a reduction in the spatial resolution to 88 mu m (averaged over the full drift range).

  3. BEBC, the Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 metres in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scientists from some fifty laboratories through...

  4. On skin expansion.

    Science.gov (United States)

    Pamplona, Djenane C; Velloso, Raquel Q; Radwanski, Henrique N

    2014-01-01

    This article discusses skin expansion without considering cellular growth of the skin. An in vivo analysis was carried out that involved expansion at three different sites on one patient, allowing for the observation of the relaxation process. Those measurements were used to characterize the human skin of the thorax during the surgical process of skin expansion. A comparison between the in vivo results and the numerical finite elements model of the expansion was used to identify the material elastic parameters of the skin of the thorax of that patient. Delfino's constitutive equation was chosen to model the in vivo results. The skin is considered to be an isotropic, homogeneous, hyperelastic, and incompressible membrane. When the skin is extended, such as with expanders, the collagen fibers are also extended and cause stiffening in the skin, which results in increasing resistance to expansion or further stretching. We observed this phenomenon as an increase in the parameters as subsequent expansions continued. The number and shape of the skin expanders used in expansions were also studied, both mathematically and experimentally. The choice of the site where the expansion should be performed is discussed to enlighten problems that can lead to frustrated skin expansions. These results are very encouraging and provide insight into our understanding of the behavior of stretched skin by expansion. To our knowledge, this study has provided results that considerably improve our understanding of the behavior of human skin under expansion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. The Lost Foam method – pre-expansion process

    Directory of Open Access Journals (Sweden)

    T. Pacyniak

    2010-04-01

    Full Text Available In the study, a pre-expansion station, designed by authors, was presented. It consists of a batch pre-expander with a 90 liters capacity foaming chamber, equipped with fluidized-solid dryer of pre-expanded beads and a pneumatic transport system of granules to the silo. Steam is delivered to the pre-expander from the electric vapor generator type LW 40.1. In the study, work principle of the pre-expansion station and pre-expansion tests carried out on this position were presented.

  6. Purging device for suppression chamber

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, Koichi.

    1987-11-14

    Purpose: To completely drive out air or the like in the suppression chamber in a short period of time thereby protect bent pipes from embrittled rupture. Constitution: Nitrogen gases, etc. entering through the inlet penetration to the inside of a reactor container are guided downwardly through communication pipeways, and the released downwardly in a stable manner while the blowing speed being retained by blowing mechanisms. Released nitrogen gases, etc. diffuse along the water surface of the suppression chamber and fill the inside of the chamber from below. Air, etc. in the suppression chamber prior to the supply of nitrogen gas, etc. is discharged through the exit penetration from the purging discharge pipe smoothly to the outside. In this way, air is replaced with nitrogen gas, etc., the released nitrogen is not directly blown to bent pipe, the operation is simplified, and the charge/discharge operation can be made in a short time efficiently. (Kamimura, M.).

  7. Vaporization chambers and associated methods

    Science.gov (United States)

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  8. The multigap resistive plate chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zeballos, E. Cerron [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Crotty, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Hatzifotiadou, D. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Valverde, J. Lamas [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Univ. Louis Pasteur, Strasbourg (France); Neupane, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Williams, M. C. S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Zichichi, A. [Univ. of Bologna, Bologna (Italy)

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  9. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  10. Bridges Expansion Joints

    Directory of Open Access Journals (Sweden)

    Sergey W. Kozlachkow

    2012-05-01

    Full Text Available The survey is concerned with the expansion joints, used in bridge constructions to compensate medium and significant operational linear and spatial displacements between adjacent spans or between bridge span and pier. The analysis of design features of these types of expansion joints, their advantages and disadvantages, based on operational experience justified the necessity to design constructions, meeting the modern demands imposed to expansion joints.

  11. Anterior chamber depth during hemodialysis

    Directory of Open Access Journals (Sweden)

    Gracitelli CPB

    2013-08-01

    Full Text Available Carolina Pelegrini Barbosa Gracitelli,1 Francisco Rosa Stefanini,1 Fernando Penha,1 Miguel Ângelo Góes,2 Sérgio Antonio Draibe,2 Maria Eugênia Canziani,2 Augusto Paranhos Junior1 1Ophthalmology Department, 2Division of Nephrology, Federal University of São Paulo – UNIFESP, São Paulo, Brazil Background: Exacerbation of chronic glaucoma or acute glaucoma is occasionally observed in patients undergoing hemodialysis (HD because of anterior chamber depth changes during this therapy. Purpose: To evaluate anterior chamber depth and axial length in patients during HD sessions. Methods: A total of 67 eyes of 35 patients were prospectively enrolled. Axial length and anterior chamber depth were measured using ultrasonic biometry, and these measures were evaluated at three different times during HD sessions. Body weight and blood pressure pre- and post-HD were also measured. Results: There was no difference in the axial length between the three measurements (P = 0.241. We observed a significantly decreased anterior chamber depth (P = 0.002 during HD sessions. Conclusion: Our results support the idea that there is a change in anterior chamber depth in HD sessions. Keywords: anterior chamber, hemodialysis, axial length, acute angle-closure glaucoma

  12. Bridges Expansion Joints

    National Research Council Canada - National Science Library

    Sergey W. Kozlachkow

    2012-01-01

    .... The analysis of design features of these types of expansion joints, their advantages and disadvantages, based on operational experience justified the necessity to design constructions, meeting...

  13. Emulsion Chamber Technology Experiment (ECT)

    Science.gov (United States)

    Gregory, John C.; Takahashi, Yoshiyuki

    1996-01-01

    The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

  14. Plasma chemistry in wire chambers

    Energy Technology Data Exchange (ETDEWEB)

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.

  15. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  16. Modifications of a Composite-Material Combustion Chamber

    Science.gov (United States)

    Williams, Brian E.; McNeal, Shawn R.

    2005-01-01

    Two short reports discuss modifications of a small, lightweight combustion chamber that comprises a carbon/carbon composite outer shell and an iridium/ rhenium inner liner. The first report discusses chamber design modifications made as results of hot-fire tests and post-test characterization. The Books & Reports 32 NASA Tech Briefs, June 2005 modifications were intended to serve a variety of purposes, including improving fabrication, reducing thermal-expansion mismatch stresses, increasing strength-to-weight ratios of some components, and improving cooling of some components. The second report discusses (1) the origin of stress in the mismatch between the thermal expansions of the Ir/Re liner and a niobium sleeve and flange attached to the carbon/ carbon shell and (2) a modification intended to relieve the stress. The modification involves the redesign of an inlet connection to incorporate a compressible seal between the Ir/Re liner and the Nb flange. A nickel alloy was selected as the seal material on the basis of its thermal-expansion properties and its ability to withstand the anticipated stresses, including the greatest stresses caused by the high temperatures to be used in brazing during fabrication.

  17. Combustion chamber and thermal vapor stream producing apparatus and method

    Science.gov (United States)

    Sperry, John S.; Krajicek, Richard W.; Cradeur, Robert R.

    1978-01-01

    A new and improved method and apparatus for burning a hydrocarbon fuel for producing a high pressure thermal vapor stream comprising steam and combustion gases for injecting into a subterranean formation for the recovery of liquefiable minerals therefrom, wherein a high pressure combustion chamber having multiple refractory lined combustion zones of varying diameters is provided for burning a hydrocarbon fuel and pressurized air in predetermined ratios injected into the chamber for producing hot combustion gases essentially free of oxidizing components and solid carbonaceous particles. The combustion zones are formed by zones of increasing diameters up a final zone of decreasing diameter to provide expansion zones which cause turbulence through controlled thorough mixing of the air and fuel to facilitate complete combustion. The high pressure air and fuel is injected into the first of the multiple zones where ignition occurs with a portion of the air injected at or near the point of ignition to further provide turbulence and more complete combustion.

  18. Conformal expansions and renormalons

    CERN Document Server

    Brodsky, S J; Grunberg, G; Rathsman, J; Brodsky, Stanley J.; Gardi, Einan; Grunberg, Georges; Rathsman, Johan

    2001-01-01

    The coefficients in perturbative expansions in gauge theories are factoriallyincreasing, predominantly due to renormalons. This type of factorial increaseis not expected in conformal theories. In QCD conformal relations betweenobservables can be defined in the presence of a perturbative infraredfixed-point. Using the Banks-Zaks expansion we study the effect of thelarge-order behavior of the perturbative series on the conformal coefficients.We find that in general these coefficients become factorially increasing.However, when the factorial behavior genuinely originates in a renormalonintegral, as implied by a postulated skeleton expansion, it does not affect theconformal coefficients. As a consequence, the conformal coefficients willindeed be free of renormalon divergence, in accordance with previousobservations concerning the smallness of these coefficients for specificobservables. We further show that the correspondence of the BLM method with theskeleton expansion implies a unique scale-setting procedure. Th...

  19. A dual deformable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2009-01-01

    There is disclosed an arrangement for measuring the effectiveness of a shielding material against electromagnetic fields. The arrangement comprises a first and a second reverberation chamber sharing a common wall. The common wall is partly made of the shielding material. A first antenna is arranged

  20. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The same vacuum chamber as in 7810256, read the detailed description there. Here, the 4 strip-shaped ion-getter pumps are poised at the entrance to their slots. Ion-getter pumps were not retained, thermal getter pumps were chosen instead (see 8301153 and 8305170).

  1. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  2. Testing an hydrogen streamer chamber

    CERN Multimedia

    1975-01-01

    A 2x10 cm gap streamer chamber, 35x55 cm2 in surface, was built and tested at CERN. Good tracks of cosmic rays were obtained up to atmospheric pressure, see F. Rohrbach et al, CERN-LAL (Orsay) Collaboration, Nucl. Instr. Methods 141 (1977) 229. Michel Cathenoz stand on the center.

  3. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  4. Metal explosion chambers: designing, manufacturing, application

    Science.gov (United States)

    Stoyanovskii, O. I.; Zlobin, B. S.; Shtertser, A. A.; Meshcheryakov, Y. P.

    2017-10-01

    Designing of explosion chambers is based on research investigations of the chamber body stress-strain state, which is determined by numerical computation and experimentally by the strain gage technique. Studies show that chamber bottoms are the most loaded elements, and maximal stresses arise in chamber poles. Increasing the shell thickness around poles by welding-in an insert is a simple and saving way to solve this problem. There are structural solutions, enabling reliable hermetic closure and preventing leakage of detonation products from the chamber. Explosion chambers are employed in scientific research and in different industrial applications: explosive welding and hardening, synthesis of new materials, disposal of expired ammunition, and etc.

  5. Growing and Analyzing Biofilms in Flow Chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic...... conditions, and the environment can be carefully controlled and easily changed. The protocols in this unit include construction of the flow chamber and the bubble trap, assembly and sterilization of the flow chamber system, inoculation of the flow chambers, running of the system, image capture and analysis...

  6. Resonant state expansions

    Energy Technology Data Exchange (ETDEWEB)

    Lind, P.

    1993-02-01

    The completeness properties of the discrete set of bound state, virtual states and resonances characterizing the system of a single nonrelativistic particle moving in a central cutoff potential is investigated. From a completeness relation in terms of these discrete states and complex scattering states one can derive several Resonant State Expansions (RSE). It is interesting to obtain purely discrete expansion which, if valid, would significantly simplify the treatment of the continuum. Such expansions can be derived using Mittag-Leffler (ML) theory for a cutoff potential and it would be nice to see if one can obtain the same expansions starting from an eigenfunction theory that is not restricted to a finite sphere. The RSE of Greens functions is especially important, e.g. in the continuum RPA (CRPA) method of treating giant resonances in nuclear physics. The convergence of RSE is studied in simple cases using square well wavefunctions in order to achieve high numerical accuracy. Several expansions can be derived from each other by using the theory of analytic functions and one can the see how to obtain a natural discretization of the continuum. Since the resonance wavefunctions are oscillating with an exponentially increasing amplitude, and therefore have to be interpreted through some regularization procedure, every statement made about quantities involving such states is checked by numerical calculations.Realistic nuclear wavefunctions, generated by a Wood-Saxon potential, are used to test also the usefulness of RSE in a realistic nuclear calculation. There are some fundamental differences between different symmetries of the integral contour that defines the continuum in RSE. One kind of symmetry is necessary to have an expansion of the unity operator that is idempotent. Another symmetry must be used if we want purely discrete expansions. These are found to be of the same form as given by ML. (29 refs.).

  7. Virial Expansion Bounds

    Science.gov (United States)

    Tate, Stephen James

    2013-10-01

    In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

  8. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  9. Development of multiwire proportional chambers

    CERN Multimedia

    Charpak, G

    1969-01-01

    It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

  10. GBO RF Anechoic Chamber & Antenna Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  11. Wake Expansion Models

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    Different models of wake expansion are presented in this chapter: the 1D momentum theory model, the cylinder analog model and Theodorsen’s model. Far wake models such as the ones from Frandsen or Rathmann or only briefly mentioned. The different models are compared to each other. Results from thi...... this chapter are used in Chap. 16 to link near-wake and far-wake parameters and in Chap. 20 to study the influence of expansion on tip-losses....

  12. Nuclear expansion with excitation

    Energy Technology Data Exchange (ETDEWEB)

    De, J.N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Samaddar, S.K. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Vinas, X. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Centelles, M. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain)]. E-mail: mario@ecm.ub.es

    2006-07-06

    The expansion of an isolated hot spherical nucleus with excitation energy and its caloric curve are studied in a thermodynamic model with the SkM{sup *} force as the nuclear effective two-body interaction. The calted results are shown to compare well with the recent experimental data from energetic nuclear collisions. The fluctuations in temperature and density are also studied. They are seen to build up very rapidly beyond an excitation energy of {approx}9 MeV/u. Volume-conserving quadrupole deformation in addition to expansion indicates, however, nuclear disassembly above an excitation energy of {approx}4 MeV/u.

  13. Uniform gradient expansions

    Directory of Open Access Journals (Sweden)

    Massimo Giovannini

    2015-06-01

    Full Text Available Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  14. Design of a Fully Anechoic Chamber

    OpenAIRE

    Rusz, Roman

    2015-01-01

    This thesis deals with fully anechoic chamber design. The main aim of this thesis is to design fully anechoic chamber according to acoustics laws and customers (Honeywell’s) requirements. The fully anechoic chamber will be used for measuring sound and vibration quantities. This work is divided into two main parts. The first part deals with the general anechoic chamber theory and all its related design aspects. The second part, practical part, focus on specific design according to requirements...

  15. Vacuum chamber at intersection I-6

    CERN Multimedia

    1971-01-01

    The vacuum chamber at intersection region I-6, one of these where experiments in colliding-beam physics will be taking place. The "wheels" prevent the thin wall (1.5 mm) of the chamber from collapsing. The chamber is equipped with heating tapes and its wrapped in thermal insulation. Residual gas pressure at this and other similar regions is around 10_11.

  16. Making a Fish Tank Cloud Chamber

    Science.gov (United States)

    Green, Frances

    2012-01-01

    The cloud chambers described here are large, made from readily available parts, simple to set up and always work. With no source in the chamber, background radiation can be observed. A large chamber means that a long rod containing a weakly radioactive material can be introduced, increasing the chance of seeing decays. Details of equipment and…

  17. A Sensitive Cloud Chamber without Radioactive Sources

    Science.gov (United States)

    Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

    2012-01-01

    We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

  18. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...

  19. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic cond...

  20. Chamber B Thermal/Vacuum Chamber: User Test Planning Guide

    Science.gov (United States)

    Montz, Mike E.

    2012-01-01

    Test process, milestones and inputs are unknowns to first-time users of Chamber B. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.

  1. Examining the influence of humidity on reference ionization chamber performance.

    Science.gov (United States)

    McEwen, Malcolm R; Taank, Jaswinder

    2017-02-01

    International dosimetry protocols require measurements made with a vented ionization chamber to be corrected for the influence of air density by using the standard temperature-pressure correction factor. The effect of humidity, on the other hand, is generally ignored with the provision that the relative humidity (RH) is within certain limits (typically 20% to 80%). However, there is little experimental data in the published literature as to the true effect of humidity on modern reference-class ionization chambers. This investigation used two different radiation beams - a Co-60 irradiator and an Sr-90 check source - to examine the effect of humidity on several Farmer-type ionization chambers. An environmental cabinet controlled the humidity. For the Co-60 beam, the irradiation was external, whereas for the Sr-90 measurements, the source itself was placed within the cabinet. Extensive measurements were carried out to ensure that the experimental setup provided reproducible readings. Four chamber types were investigated: IBA FC65-G, IBA FC65-P, PTW 30013 and Exradin A19. The different wall materials provided potentially different mechanical responses (i.e., in terms of expansion/contraction) to the water content in the air. The relative humidity was varied between 8% and 98% and measurements were made with both increasing and decreasing humidity to investigate any possible hysteresis effects. Measurements in Co-60 were consistent with the published data obtained with primary standard cavity chambers in ICRU Report 31 (i.e., a very small variation 10%). The measurements in the Sr-90 field showed no dependence with the relative humidity, within the measurement uncertainties (0.05%, k = 1). Very good repeatability of the ionization current was obtained over successive wet/dry cycles, no hysteresis was observed, and there was no dependence on chamber type. These results indicate that humidity has no significant effect on these particular types of ionization chambers

  2. AUTO-EXPANSIVE FLOW

    Science.gov (United States)

    Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding...

  3. Rethinking expansive learning

    DEFF Research Database (Denmark)

    Kolbæk, Ditte; Lundh Snis, Ulrika

    discussion forum on Google groups, they created new ways of reflecting and learning. We used netnography to select qualitative postings from the online community and expansive learning concepts for data analysis. The findings show how students changed practices of organisational learning...

  4. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London...

  5. MEMS CLOSED CHAMBER HEAT ENGINE AND ELECTRIC GENERATOR

    Science.gov (United States)

    Landis, Geoffrey A. (Inventor)

    2005-01-01

    A heat engine, preferably combined with an electric generator, and advantageously implemented using micro-electromechanical system (MEMS) technologies as an array of one or more individual heat engine/generators. The heat engine is based on a closed chamber containing a motive medium, preferably a gas; means for alternately enabling and disabling transfer of thermal energy from a heat source to the motive medium; and at least one movable side of the chamber that moves in response to thermally-induced expansion and contraction of the motive medium, thereby converting thermal energy to oscillating movement. The electrical generator is combined with the heat engine to utilize movement of the movable side to convert mechanical work to electrical energy, preferably using electrostatic interaction in a generator capacitor. Preferably at least one heat transfer side of the chamber is placed alternately into and out of contact with the heat source by a motion capacitor, thereby alternately enabling and disabling conductive transfer of heat to the motive medium.

  6. A silicon microstrip gas chamber

    Energy Technology Data Exchange (ETDEWEB)

    Van der Marel, J. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Van den Bogaard, A. (Delft Inst. of Microelectronics and Submicrotechnology, Delft Univ. of Tech. (Netherlands)); Van Eijk, C.W.E. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Hollander, R.W. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Okx, W.J.C. (Radiation Technology Group, Faculty of Applied Physics, Delft Univ. of Tech. (Netherlands)); Sarro, P.M. (Delft Inst. of Microelectronics and Submicrotechnology, Delft Univ. of Tech. (Netherlands))

    1994-09-01

    We are manufacturing microstrip gas chambers (MSGC) on silicon with an insulating SiO[sub 2] layer. To study the effect of the sheet resistance of the SiO[sub 2] on the operation of the detector several processes to modify the SiO[sub 2] layer have been investigated: ion implantation, boron and phosphorus diffusion, phosphosilicate glass evaporation and polycrystalline silicon deposition. The dependence of the gas gain on the potentials of the different electrodes and the long term stability have been studied. ((orig.))

  7. The cloud chamber and its metamorphoses; La chambre a brouillard et ses metamorphoses

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, K. [Palais de la Decouverte, Dept. de Physique, 75 - Paris (France)

    2010-04-15

    The stunning invention of the Wilson chamber in 1911 stayed almost ignored by the physicist community for more than a decade although it permitted the visualization of the track of an alpha particle as soon as 1911. The detection principle is based on the expansion of a saturated vapor that allows the visualization of a ionizing particle motion through the formation of droplets around the ions created all along the particle path. The original device was too slow (only one expansion per minute) to be used for the detection of rare events unless to operate it for months or years. A decisive step was made in the beginning of the twenties by the Japanese physicist Takeo Shimizu, working at the Cavendish Laboratory. He managed to automate the Wilson chamber and to equip it with 2 mirrors and a camera. This new generation allowed 5 expansion per second and the knowledge of the particle track orientation in space thanks to a simultaneous photography following 2 perpendicular directions. A rate of 4 shots a minute was achieved. The Wilson chamber was constantly improved during its 30 years long career and was only supplanted by the bubble chamber in the fifties. (A.C.)

  8. Pupillary block glaucoma following implantation of a posterior chamber pseudophakos in the anterior chamber.

    Directory of Open Access Journals (Sweden)

    Mandal Anil

    2002-01-01

    Full Text Available Pupillary block glaucoma is a common complication of cataract surgery, especially following anterior chamber intraocular lens implantation. We report a case of pupillary block glaucoma with a posterior chamber IOL that was implanted in the anterior chamber following a complicated extracapsular cataract extraction. The case was successfully managed by explantation of the posterior chamber lens, anterior vitrectomy, peripheral iridectomy and secondary anterior chamber intraocular lens implantation. The intraocular pressure was controlled with a single topical antiglaucoma medication.

  9. Limits to Drift Chamber Resolution

    CERN Document Server

    Riegler, Werner

    1998-01-01

    ATLAS (A Large Toroidal LHC Apparatus) will be a general-purpose experiment at the Large Hadron Collider that will be operational at CERN in the year 2004. The ATLAS muon spectrometer aims for a momentum resolution of 10% for a transverse momentum of pT=1TeV. The precision tracking devices in the muon system will be high pressure drift tubes (MDTs) with a single wire resolution of 1100 chambers covering an area of ≈ 2500m2. The high counting rates in the spectrometer as well as the aim for excellent spatial resolution and high efficiency put severe constraints on the MDT operating parameters. This work describes a detailed study of all the resolution limiting factors in the ATLAS environment. A ’full chain’ simulation of the MDT response to photons and charged particles as well as quantitative comparisons with measurements was performed. The good agreement between simulation and measurements resulted in a profound understanding of the drift chamber processes and the individual contributions to the spat...

  10. Physicist makes muon chamber sing

    CERN Document Server

    2007-01-01

    This Monitored Drift Tube detector, consisting of argon-CO2-filled aluminium tubes with a wire down the centre of each, will track muons in ATLAS; Tiecke used a single tube from one of these detectors to create the pipes in his organ. Particle physicists can make good musicians; but did you know particle detectors can make good music? That's what NIKHEF physicist Henk Tiecke learned when he used pipes cut from the ATLAS Monitored Drift Tube detector (MDT) to build his own working Dutch-style barrel organ in the autumn of 2005. 'I like to work with my hands,' said Tiecke, who worked as a senior physicist at NIKHEF, Amsterdam, on ZEUS until his retirement last summer. Tiecke had already constructed his barrel organ when he visited some colleagues in the ATLAS muon chambers production area at Nikhef in 2005. He noticed that the aluminium tubes they were using to build the chambers were about three centimetres in diameter-just the right size for a pipe in a barrel organ. 'The sound is not as nice as from wooden...

  11. IKEA's International Expansion

    OpenAIRE

    Harapiak, Clayton

    2013-01-01

    This case concerns a global retailing firm that is dealing with strategic management and marketing issues. Applying a scenario of international expansion, this case provides a thorough analysis of the current business environment for IKEA. Utilizing a variety of methods (e.g. SWOT, PESTLE, McKinsey Matrix) the overall objective is to provide students with the opportunity to apply their research skills and knowledge regarding a highly competitive industry to develop strategic marketing strateg...

  12. Transferring calibration coefficients from ionisation chambers used for diagnostic radiology to transmission chambers.

    Science.gov (United States)

    Yoshizumi, Maíra T; Caldas, Linda V E

    2012-07-01

    In this work, the response of a double volume transmission ionisation chamber, developed at the Instituto de Pesquisas Energéticas e Nucleares, was compared to that of a commercial transmission chamber. Both ionisation chambers were tested in different X-ray beam qualities using secondary standard ionisation chambers as reference dosimeters. These standard ionisation chambers were a parallel-plate and a cylindrical ionisation chambers, used for diagnostic radiology and mammography beam qualities, respectively. The response of both transmission chambers was compared to that of the secondary standard chambers to obtain coefficients of equivalence. These coefficients allow the transmission chambers to be used as reference equipment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Character expansion of matrix integrals

    OpenAIRE

    van de Leur, J. W.; Orlov, A. Yu.

    2016-01-01

    We consider character expansion of tau functions and multiple integrals in characters of orhtogonal and symplectic groups. In particular we consider character expansions of integrals over orthogonal and over symplectic matrices.

  14. Tests of anechoic chamber for aeroacoustics investigations

    Science.gov (United States)

    Palchikovskiy, V. V.; Bersenev, Yu. V.; Makashov, S. Yu.; Belyaev, I. V.; Korin, I. A.; Sorokin, E. V.; Khramtsov, I. V.; Kustov, O. Yu.

    2016-10-01

    The paper presents the results of qualification tests in the new anechoic chamber of Perm National Research Polytechnic University (PNRPU) built in 2014-2015 and evaluation of the chamber quality in aeroacoustic experiments. It describes design features of the chamber and its sound-absorption lining. The qualification tests were carried out with tonal and broadband noise sources in the frequency range 100 Hz - 20 kHz for two different cases of the source arrangement. In every case, measurements were performed in three directions by traverse microphones. Qualification tests have determined that in the chamber there is a free acoustic field within radius of 2 m for tonal noise and 3 m for broadband noise. There was also evaluated acoustic quality of the chamber by measurements of the jet noise and vortex ring noise. The results of the experiments demonstrate that PNRPU anechoic chamber allows the aeroacoustic measurements to be performed to obtain quantitative results.

  15. The CAST Time Projection Chamber

    CERN Document Server

    Autiero, D.; Carmona, J.M.; Cebrian, S.; Chesi, E.; Davenport, M.; Delattre, M.; Di Lella, L.; Formenti, F.; Irastorza, I.G.; Gomez, H.; Hasinoff, M.; Lakic, B.; Luzon, G.; Morales, J.; Musa, L.; Ortiz, A.; Placci, A.; Rodriguez, A.; Ruz, J.; Villar, J.A.; Zioutas, K.

    2007-01-01

    One of the three X-ray detectors of the CAST experiment searching for solar axions is a Time Projection Chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity X-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is safely set during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62 %. Shielding has been installed around the detector, lowering the background level to 4.10 x 10^-5 counts/cm^2/s/keV between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass.

  16. Time Projection Chamber at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P.; Dixit, M.S.; Hargrove, C.K.; Mes, H.; Bennett, A.; Macdonald, J.A.

    1984-01-01

    The Time Projection Chamber at TRIUMF is being used to search for muon-electron conversion. The best spatial resolution in the TPC, sigma approx. = 200 ..mu..m, occurs at the minimum drift length and for an optimum track-to-anode crossing angle determined by the magnetic field. The observed resolution is dependent on the diffusion of the drifting electrons, the track-to-anode crossing angle, vector E X vector B effects near the anode wire and the discrete nature of the ionization process. Distortion due to positive ions leaking back into the drift volume from the anode wire region have been nearly eliminated by the use of a pulsed dual grid system.

  17. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

  18. Drift chamber tracking with neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, C.S.; Denby, B.; Haggerty, H.

    1992-10-01

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed.

  19. Bicone vacuum chamber for ISR intersection

    CERN Multimedia

    1975-01-01

    This is one of the bicone chambers made of titanium for experiment R 702. The central corrugated part had a very thin titanium wall (0.28 mm). The first of these chambers collapsed in its central part when baked at 300 C (August 1975). After an intensive effort to develop better quality and reproducible welds for this special material, the ISR workshop was able to build two new chambers of this type. One of them was installed at I 7 for R 702 in 1976 and worked perfectly. It was at that time the most "transparent" intersection vacuum chamber. See also 7609219, 7609221.

  20. Anechoic chamber for VHF and UHF bands

    Science.gov (United States)

    Morikawa, Takao; Sugiura, Akira; Harima, Katsushige; Masuzawa, Hiroshi

    1995-06-01

    Built in 1969, the anechoic chamber of CRL has been used to the fullest by researchers in many fields such as EMI, EMC, antenna design, standard of electric field intensity, and type approval testing. In particular, in the early days of space development in Japan, many satellite-born antennas were developed in this anechoic chamber. However, a quarter of a century has passed since its construction and deteriorated performance due to superannuation sometimes caused difficulties in experiments conducted in the chamber. In 1993, CRL constructed a Measuring Facility for Radio Research (MFRR) and the anechoic chamber for VHF-UHF bands was remodeled as one of the sub-facilities of MFRR. The remodeling work included full replacement of the electromagnetic shielding, absorbers and measurement system. Since the remodeled anechoic chamber is being used not only for EMI tests but also for other purposes, a full-anechoic chamber has been adopted. In addition the chamber has been designed for the frequency range between 30 MHz and 10 GHz. After the remodeling work, the performance of the chamber is greatly improved. The average shielding factor is better than 85 dB for all frequency ranges and the unwanted reflection characteristic is -30 dB for frequencies above 1 GHZ. This paper summarizes the remodeling work, and the specifications and performance of the remodeled anechoic chamber.

  1. Precision Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs measurements and calibration of antennas for satellites and aircraft or groundbased systems. The chamber is primarily used for optimizing antenna...

  2. D0 Central Tracking Chamber Performance Studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York (SUNY), Stony Brook, NY (United States)

    1991-01-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an $R\\Phi$ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against $\\gamma \\to e^+ e^-$ events.

  3. The Mark II Vertex Drift Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

  4. Biases in methane chamber measurements in peatlands

    Science.gov (United States)

    Juszczak, R.

    2013-03-01

    The paper presents results of CH4 emission measurements at peatland with the application of the dynamic chamber technique. The measurements were conducted in two types of chambers differing in shape, height, volume and technology used to assure their tightness. The study tested how the following factors: 1) forced chamber headspace mixing or its absence, 2) mistakes of the person conducting measurements, 3) improper application of linear technique for calculating CH4 fluxes, and 4) simulated air sampling typical for static chambers, influence the significance of errors and the underestimation rate of CH4 fluxes measured in situ. It was indicated that chamber headspace mixing allows estimating methane fluxes with a smaller error than in the case of measurements conducted without mixing, and CH4 fluxes in such conditions can be 47 to 58% higher (depending on the chamber type) than in a chamber without fans. Using dynamic chambers and a fast analyzer to measure methane fluxes allows shortening the methane measurement process to a few minutes. On the other hand, using static chambers for methane flux measurements may lead to 70% underestimation of the calculated flux.

  5. D0 central tracking chamber performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York, Stony Brook, NY (United States)

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an RΦ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against γ → e + e- events.

  6. Laboratory simulation of Hot Jupiters atmosphere expansion

    Science.gov (United States)

    Prokopov, P. A.; Shaikhislamov, I. F.; Zakharov, Yu P.; Posukh, V. G.; Melekhov, A. V.; Boyarintsev, E. L.; Ponomarenko, A. G.

    2017-11-01

    Hot Jupiters (HJ) are exoplanets, gas giants with low orbits (≤ 0.1 a.u.). The stellar X-ray and ultraviolet (XUV) radiation energy deposition result in heating ionization and the consequent expansion of planetary atmosphere. Expansion of upper atmosphere under certain conditions could be so large that the majority of light atmospheric constituents overcome the gravitational binding and escape from the planet in a form of hydrodynamic wind. Besides interaction of two counter-streaming plasma flows (stellar wind and ionized upper layers of planet atmosphere), each of this flows interact with planetary magnetic field. In such complex situation laboratory simulation can provide data that can’t be obtained by computer simulation or observation. Experiment was carried out on KI-1 facility: high-vacuum chamber 5m long, 1.2 m in diameter with pressure ∼ 10-6 Torr. Magnetic dipole with two attached laser targets played the role of a planet, and background plasma from θ-pinch used for simulation of stellar wind. As a result, data on a behavior of plasma density and magnetic field were obtained. The novel phenomenon was registered: magnetic field is transferred by the cloud of laser plasma, which was not observed before in experiments or calculations.

  7. Wide-band antennas for reverberation chambers

    NARCIS (Netherlands)

    Vogt-Ardatjew, R.A.; van de Beek, G.S.; Leferink, Frank Bernardus Johannes

    2012-01-01

    Shielding effectiveness measurements in a dual vibrating intrinsic reverberation chamber results in very repeatable results for a large frequency range and large dynamic range. Antennas in reverberation chambers do not need any gain, but the losses should be low and the dimensions should be small.

  8. Shielding Effectiveness Measurements using a Reverberation Chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Bergsma, J.G.; Bergsma, Hans; van Etten, Wim

    2006-01-01

    Shielding effectiveness measurements have been performed using a reverberation chamber. The reverberation chamber methodology as we1l as the measurement setup is described and some results are given. Samples include glass reinforced plastic panels, aluminum panels with many holes, wire mesh, among

  9. 21 CFR 866.2120 - Anaerobic chamber.

    Science.gov (United States)

    2010-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic (oxygen...

  10. An ionization chamber with magnetic levitated electrodes

    CERN Document Server

    Kawaguchi, T

    1999-01-01

    A new type of ionization chamber which has magnetically levitated electrodes has been developed. The electrodes are supplied voltages for the repelling of ions by a battery which is also levitated with the electrodes. The characteristics of this ionization chamber are investigated in this paper.

  11. Results from the MAC Vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.N.

    1987-05-01

    The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 ..mu..m in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed.

  12. Validation of a fully anechoic chamber

    NARCIS (Netherlands)

    Mandaris, Dwi; Moonen, Dominicus Johannes Guilielmus; van de Beek, G.S.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2016-01-01

    This paper describes a technique to characterize the performance of a Fully Anechoic Chamber (FAC) from 500 MHz to 3 GHz based on S-Parameter analysis with antennas and a Vector Network Analyzer (VNA. The measurements have been performed by placing one antenna inside the chamber and performing S11

  13. HVAC&R Equipment Environmental Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description:Large "Truck" ChamberThe large "truck" chamber provides controlled air conditions from -7 °C (20 °F) to 65 °C (150 °F).Air-Conditioner and Heat Pump Test...

  14. The HARP Time Projection Chamber

    CERN Document Server

    Vidal-Sitjes, G

    2003-01-01

    A novel apparatus for the calibration of the HARP Time Projection Chamber has been designed, developed and built. The apparatus consists of a large number of point-like photo-electron sources located at precise positions inside the detector volume. The photo-electron sources are optical quartz fibers on which one end is coated with an aluminum layer of $\\sim$80{\\AA} thickness and are held in place on the High Voltage membrane. The fibers are used to guide UV laser light pulses that generate photoelectrons on the fiber tips and these act as photo-electron emitters. The photoelectrons drift inside the detector and produce the calibration signals. The technique allows to asses $E\\times B$ distortions and to measure drift velocity, ion feedback and time stability in real time. The analog signals generated by the TPC front-end electronics have been characterized. Different methods to extract the amplitude and time of occurrence from the digitized signals have been studied and compared. Fast estimators, like the su...

  15. Gargamelle : this film recalls design, construction and operation of this heavy liquid bubble chamber named thus for its size of giantess

    CERN Document Server

    Sidney Jezequel

    1971-01-01

    1970 : in the Saclay Nuclear Research Center, the assembly of the two largest bubble chambers ever built was in the final stage; Mirabelle for the Soviet Serpukhov accelerator and Gargamelle for the CERN European accelerator ... Comments : Saturn particle accelerator at Saclay, most powerful in 1959. Since then: ISR, Brookhaven, Serpakov. History of bubble chambers. Ecole Polytechnique. Gargamelle, Rabelais legendary giant, wife of Gargantua. Demands of building of chamber body. Bubble chamber a kind of photographers studio. Animation explaining how a bubble chamber works. Decompression/recompression cycle. Film. * Most dramatic moment in film is when the man enters the chamber to paint it with an absolute photographic black. Magnet. Largest conventional magnet every built. Could compare that with the L3 magnet, to get a feel for the size expansion in 15 years. Assembly at CERN. Cost $5.000.000. Operation. Scanning. Ends with need to build bigger machines to get at secrets of nature. In a few years Gargamell...

  16. Underwater expansion wave focusing by reflecting at the air interface

    Science.gov (United States)

    Ohtani, K.; Ogawa, T.

    2017-02-01

    This paper reports a preliminarily experimental result of high-speed shadowgraph optical visualization of underwater expansion wave focusing by using a simple two-dimensional wedge model for understanding of shock wave interaction phenomena in simulated biomedical materials. Underwater shock wave generated by detonating a micro-explosive (10 mg silver azide pellet) in a small chamber. The generated underwater shock wave was interacted with a wedge shaped interface between water and air divided by a thin film, and an expansion wave was generated by reflection at the interface. The process of underwater expansion wave generation and focusing phenomena was visualized by shadowgraph method and recorded by ultra-high-speed framing camera. Underwater shock wave was reflected as an expansion wave from the interface between water and air at the both side and focused and then cavitation bubble was created by pressure decreasing at the expansion wave focusing area. The pressure histories were measured simultaneously with high-speed optical visualization by a needle type pressure sensor. At the focusing area, the pressure was decreased rapidly, the negative peak pressure was the lowest.

  17. Conformal expansions and renormalons

    CERN Document Server

    Gardi, E; Gardi, Einan; Grunberg, Georges

    2001-01-01

    The large-order behaviour of QCD is dominated by renormalons. On the other hand renormalons do not occur in conformal theories, such as the one describing the infrared fixed-point of QCD at small beta_0 (the Banks--Zaks limit). Since the fixed-point has a perturbative realization, all-order perturbative relations exist between the conformal coefficients, which are renormalon-free, and the standard perturbative coefficients, which contain renormalons. Therefore, an explicit cancellation of renormalons should occur in these relations. The absence of renormalons in the conformal limit can thus be seen as a constraint on the structure of the QCD perturbative expansion. We show that the conformal constraint is non-trivial: a generic model for the large-order behaviour violates it. We also analyse a specific example, based on a renormalon-type integral over the two-loop running-coupling, where the required cancellation does occur.

  18. Electromagnetic fields and Green's functions in elliptical vacuum chambers

    Science.gov (United States)

    Persichelli, S.; Biancacci, N.; Migliorati, M.; Palumbo, L.; Vaccaro, V. G.

    2017-10-01

    In this paper, we discuss the electromagnetic interaction between a point charge travelling inside a waveguide of elliptical cross section, and the waveguide itself. By using a convenient expansion of the Mathieu functions, useful in particular for treating a variety of problems in applied mathematics and physics with elliptic geometry, we first obtain the longitudinal electromagnetic field of a point charge (Green's function) in free space in terms of elliptical coordinates. This expression allows, then, to calculate the scattered field due to the boundary conditions in our geometry. By summing the contribution of the direct or primary field and the indirect field scattered by the boundary, after a careful choice of some expansion expressions, we derive a novel formula of the longitudinal electric field, in any transverse position of the elliptical cross section, generated by the charge moving along the longitudinal axis of the waveguide. The obtained expression is represented in a closed form, it can be differentiated and integrated, it can be used to fully describe the radiation process of a particle beam travelling inside a waveguide of elliptical cross section, and it is valid for any elliptic geometry. The equations are used to evaluate the coupling impedance due to indirect space charge in case of elliptical geometry. In addition, they are useful as preliminary studies for the determination of the coupling impedance in different cases involving elliptic vacuum chambers, as, for example, the effect of the finite conductivity of the beam pipe wall or the geometrical variation of the vacuum chamber due to elliptic step transitions existing in some accelerators.

  19. Golden Jubilee photos - BEBC, the Big European Bubble Chamber

    CERN Multimedia

    2004-01-01

    The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 metres in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scient...

  20. Permissible limit for mandibular expansion.

    Science.gov (United States)

    Motoyoshi, Mitsuru; Shirai, Sawa; Yano, Shinya; Nakanishi, Kotoe; Shimizu, Noriyoshi

    2005-04-01

    In recent years, mandibular expansion has been increasingly performed in conjunction with orthodontic treatment. Lateral tipping of the molars associated with mandibular expansion should, however, be considered, because excessive expansion may result in excessive buccal tooth inclination, which may disturb the occlusal relationship. This study was conducted to quantitatively clarify molar movement during mandibular expansion using the Schwarz appliance to determine the permissible limit of mandibular expansion as a clinical index for inclination movement. Inclinations in the masticatory surface of the first molar and intermolar width were measured before expansion (T1), after expansion (T2), and before edgewise treatment (T3). Lower plaster models from 29 subjects treated with expansion plates were used and compared with models from 11 control subjects with normal occlusion. The average treatment change (T1-T2) in intermolar width was 5.42 mm (standard deviation 1.98), and the average angle of buccal tooth inclination was 10.16 degrees (standard deviation 3.83). No significant correlation was found between age prior to treatment and the treatment period when they were compared with the intermolar width increments and inclination angles. There was a significant positive correlation between retention duration and the amount of expansion. The regression coefficient of the angle of buccal tooth inclination during expansion to the increment of the intermolar width was approximately 0.2. This means that 1 mm of expansion is accompanied by 5 degrees of molar lateral tipping. This coefficient is clinically useful for estimating the permissible limit for mandibular expansion.

  1. Experimental investigation of the evacuation effect in expansion deflection nozzles

    Science.gov (United States)

    Taylor, N. V.; Hempsell, C. M.; Macfarlane, J.; Osborne, R.; Varvill, R.; Bond, A.; Feast, S.

    2010-02-01

    This paper provides an overview of results generated by the static test expansion-deflection rocket nozzle (STERN) project. The engine propellants were gaseous air and hydrogen, with a design chamber pressure and thrust of 102 bar and 5 kN respectively. The maximum chamber pressure achieved was restricted to 55 bar absolute, due to a conservative approach in the test programme dictated by the uncertainty in heat transfer to the pintle. Despite this, the programme achieved many successes, including the first tests of an ED nozzle in the UK; the production of significant amounts of data for both the analysis of the performance of the nozzle and the verification of analysis codes; and an improved compensation performance over that apparent from earlier work, including demonstration of attached flow to the exit plane for all chamber pressures. Whilst the wake pressure was not as high as hoped, ranging between 70% and 95% of ambient and apparently inversely related to chamber pressure, this result is still sufficiently encouraging to warrant further investigation of the type. As importantly, the data derived from the experiments, including performance analysis and wall pressure variations in time and space, are now being made available to the wider academic community, something which for commercial reasons appears to be a unique occurrence for this type of nozzle.

  2. Burial Ground Expansion Hydrogeologic Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Gaughan , T.F.

    1999-02-26

    Sirrine Environmental Consultants provided technical oversight of the installation of eighteen groundwater monitoring wells and six exploratory borings around the location of the Burial Ground Expansion.

  3. Thermoelectrically cooled cloud physics expansion chamber. [systems engineering and performance prediction

    Science.gov (United States)

    Buist, R. J.

    1977-01-01

    The design and fabrication of a thermoelectric chiller for use in chilling a liquid reservoir is described. Acceptance test results establish the accuracy of the thermal model and predict the unit performance under various conditions required by the overall spacelab program.

  4. Monitored Drift Chambers in the ATLAS Detector

    CERN Document Server

    Herten, G

    Monitored Drift Chambers (MDT) are used in the ATLAS Detector to measure the momentum of high energy muons. They consist of drift tubes, which are filled with an Ar-CO2 gas mixture at 3 bar gas pressure. About 1200 drift chambers are required for ATLAS. They are up to 6 m long. Nevertheless the position of every wire needs to be known with a precision of 20 µm within a chamber. In addition, optical alignment sensors are required to measure the relative position of adjacent chambers with a precision of 30µm. This gigantic task seems impossible at first instance. Indeed it took many years of R&D to invent the right tools and methods before the first chamber could be built according to specifications. Today, at the time when 50% of the chambers have been produced, we are confident that the goal for ATLAS can be reached. The mechanical precision of the chambers could be verified with the x-ray tomograph at CERN. This ingenious device, developed for the MDT system, is able to measure the wire position insid...

  5. Making MUSIC: A multiple sampling ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shumard, B. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)]. E-mail: shumard@phy.anl.gov; Henderson, D.J. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Rehm, K.E. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Tang, X.D. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)

    2007-08-15

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the ({alpha}, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for ({alpha}, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only ({alpha}, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the ({alpha}, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the ({alpha}, p) reaction to reach the anode segment below the reaction.

  6. LEP vacuum chamber, cross-section

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.

  7. Weld Development for Aluminum Fission Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Carl Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Jesse Norris [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-16

    The Sigma welding team was approached to help fabricate a small fission chamber (roughly ½ inch dia. x ½ inch tall cylinder). These chambers are used as radiation sensors that contain small traces of radionuclides (Cf 252, U 235, and U 238) that serve to ionize gas atoms in addition to external radiation. When a voltage is applied within the chamber, the resulting ion flow can be calibrated and monitored. Aluminum has the advantage of not forming radioactive compounds when exposed to high external radiation (except from minor Na alloy content). Since aluminum has not been used before in this application, this presented an unexplored challenge.

  8. Cloud chamber photographs of the cosmic radiation

    CERN Document Server

    Rochester, George Dixon

    1952-01-01

    Cloud Chamber Photographs of the Cosmic Radiation focuses on cloud chamber and photographic emulsion wherein the tracks of individual subatomic particles of high energy are studied. The publication first offers information on the technical features of operation and electrons and cascade showers. Discussions focus on the relationship in time and space of counter-controlled tracks; techniques of internal control of the cloud chamber; cascade processes with artificially-produced electrons and photons; and nuclear interaction associated with an extensive shower. The manuscript then elaborates on

  9. Convergence of generalized eigenfunction expansions

    Directory of Open Access Journals (Sweden)

    Mayumi Sakata

    2007-05-01

    Full Text Available We present a simplified theory of generalized eigenfunction expansions for a commuting family of bounded operators and with finitely many unbounded operators. We also study the convergence of these expansions, giving an abstract type of uniform convergence result, and illustrate the theory by giving two examples: The Fourier transform on Hecke operators, and the Laplacian operators in hyperbolic spaces.

  10. Reflectivity level of radio anechoic chambers

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1973-01-01

    A comparison between the antenna-pattern comparison technique and the free-space voltage standing-wave ratio technique for evaluating the reflectivity level of radio anechoic chambers is presented. Based on an analysis of the two techniques, it is pointed out which parameters influence the measured...... be used to measure the improvements. This work is inspired by the current discussion of finding a figure of merit for anechoic chambers. Based on the results, an evaluation procedure for anechoic chambers is indicated. However, it is pointed out and illustrated by examples that further investigations...... value of the reflectivity level. The comparison is illustrated with experimental results and it is explained why inconsistent and uncorrelated results may be found when the two methods are used. Furthermore, it is demonstrated, by introducing improvements in a chamber, how the reflectivity level can...

  11. RADAR Anechoic Chamber/RCS Measurements Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The RF Anechoic Chamber is 56 feet long by 12 feet high by 13.5 feet wide, with an adjoining electronic computer control room. A double door entrance at one end of...

  12. Developing cloud chambers with high school students

    CERN Document Server

    Ishizuka, Ryo; Sato, Shoma; Zeze, Syoji

    2013-01-01

    The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry ice free cloud chamber using salt and ice (or snow). Technical detail of the chamber is presented. We also argue how the project affects student's cognition, motivation, academic skills and behavior. The research project had been done in very similar way to those of professional researchers, i.e., planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we learn that such style of scientific activity is very effective in promoting student's motivation for learning science.

  13. High Performance Methane Thrust Chamber (HPMTC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a High-Performance Methane Thrust Chamber (HPMRE) to meet the demands of advanced chemical propulsion systems for deep-space mission...

  14. MAN-IN-SIMULANT TEST (MIST) CHAMBER

    Data.gov (United States)

    Federal Laboratory Consortium — The MIST chamber uses methyl salicylate (oil of wintergreen) vapor as a simulant for HD agent to conduct system level evaluations of chemical protective ensembles....

  15. Chamber Core Structures for Fairing Acoustic Mitigation

    National Research Council Canada - National Science Library

    Lane, Steven A; Henderson, Kyle; Williams, Andrew; Ardelean, Emil

    2007-01-01

    .... A composite chamber core fairing consists of many axial tubes sandwiched between face sheets, tubes that can be used as acoustic dampers to reduce low-frequency interior noise with virtually no added mass...

  16. Developing Cloud Chambers with High School Students

    Science.gov (United States)

    Ishizuka, Ryo; Tan, Nobuaki; Sato, Shoma; Zeze, Syoji

    The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry-ice-free cloud chamber using salt and ice (or snow). Technical details of the chamber are described. We also argue how the project have affected student's cognition, motivation, academic skills and behavior. The research project has taken steps of professional researchers, i.e., in planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we have learnt that such style of scientific activity is very effective in promoting student's motivation for learning science.

  17. New measurement methods for anechoic chamber characterization

    OpenAIRE

    Gómez Alfageme, Juan José; Sanchez Bote, José Luis; Blanco Martín, Elena

    2008-01-01

    As a continuation of the work presented in 122nd AES Convention, this paper tries to study in depth the anechoic chambers qualification. The purpose of this paper is to find parameters that allow the characterization of this type of enclosures. The proposal that becomes in this work is trying to obtain data of the anechoic chambers absorption by means of the transfer functions between pairs of microphones, or by means of the impulse response between pairs of microphones. Based on the results ...

  18. Signal shapes in a TPC wire chamber

    Science.gov (United States)

    Rossegger, S.; Riegler, W.

    2010-11-01

    We study signal shapes in Multi Wire Proportional Chambers (MWPCs) and the influence of the electron distribution around the wire on the ion tail characteristics. Simulations of the ion tail for two different geometries, different voltages and therefore gas gains were performed. These simulations are compared to measurements carried out with the ALICE TPC wire chambers for a Ne/CO 2/N 2 gas mixture, which allows to extract the avalanche spread around the anode wires of the MWPC.

  19. Georges Charpak and his multiwire chamber

    CERN Multimedia

    1970-01-01

    In 1968, Georges Charpak developed the 'multiwire proportional chamber', a gas-filled box with a large number of parallel detector wires, each connected to individual amplifiers. Linked to a computer, it could achieve a counting rate a thousand times better than existing techniques - without a camera in sight. From left to right, Georges Charpak, Fabio Sauli and Jean-Claude Santiard working on a multiwire chamber in 1970.

  20. The Gargamelle heavy liquid bubble chamber

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    This image shows the Gargamelle heavy liquid bubble chamber. It was used to detect particles in experiments at the PS between 1970 and 1976 before being moved to the SPS. In 1973, while working on the PS, it detected the first neutral current, an interaction vital to the electroweak theory. In 1978 a large fissure appeared in the body of the chamber and Gargamelle was stopped in 1979.

  1. The world's largest time projection chamber

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Peter Glassel, the technical coordinator for the ALICE time projection chamber, is seen sitting inside the detector; the largest in the world at nearly 100 cubic metres. Thousands of wires are connected to read out electronic data produced as particles are created in lead-lead collisions at the centre of the detector. These particles will cause the medium within the time projection chamber to ionise along their tracks allowing the particle paths to be recreated.

  2. On the Bantu expansion.

    Science.gov (United States)

    Rowold, Daine J; Perez-Benedico, David; Stojkovic, Oliver; Garcia-Bertrand, Ralph; Herrera, Rene J

    2016-11-15

    Here we report the results of fine resolution Y chromosomal analyses (Y-SNP and Y-STR) of 267 Bantu-speaking males from three populations located in the southeast region of Africa. In an effort to determine the relative Y chromosomal affinities of these three genotyped populations, the findings are interpreted in the context of 74 geographically and ethnically targeted African reference populations representing four major ethno-linguistic groups (Afro-Asiatic, Niger Kordofanin, Khoisan and Pygmoid). In this investigation, we detected a general similarity in the Y chromosome lineages among the geographically dispersed Bantu-speaking populations suggesting a shared heritage and the shallow time depth of the Bantu Expansion. Also, micro-variations in the Bantu Y chromosomal composition across the continent highlight location-specific gene flow patterns with non-Bantu-speaking populations (Khoisan, Pygmy, Afro-Asiatic). Our Y chromosomal results also indicate that the three Bantu-speaking Southeast populations genotyped exhibit unique gene flow patterns involving Eurasian populations but fail to reveal a prevailing genetic affinity to East or Central African Bantu-speaking groups. In addition, the Y-SNP data underscores a longitudinal partitioning in sub-Sahara Africa of two R1b1 subgroups, R1b1-P25* (west) and R1b1a2-M269 (east). No evidence was observed linking the B2a haplogroup detected in the genotyped Southeast African Bantu-speaking populations to gene flow from contemporary Khoisan groups. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Laser peripheral iridotomy changes anterior chamber architecture.

    Science.gov (United States)

    Theinert, Christian; Wiedemann, Peter; Unterlauft, Jan D

    2017-01-19

    The pressure gradient between anterior and posterior chamber in acute angle closure (AAC) and primary angle closure suspects is balanced by a sufficient laser peripheral iridotomy (LPI). The anterior chamber changes induced by LPI in patients with unilateral AAC were examined and compared to healthy eyes to define threshold values, which may help to discriminate between healthy and diseased eyes. Using Scheimpflug photography, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and central corneal thickness (CCT) were measured before and after LPI in both eyes of unilateral AAC cases. These measurements were compared to a group of healthy control eyes to determine threshold values for ACD, ACV, and ACA. The ACD, ACV, and ACA increased significantly in the 25 AAC eyes after LPI. The ACD, ACV, ACA, and CCT values in the AAC eyes obtained before LPI were compared to a control group of 59 healthy eyes with wide open chamber angles. The cutoff values revealed by receiver operating characteristic analysis were 2.1 mm for ACD, 90.5 mm2 for ACV, and 27.25° for ACA. Our results confirm the significant changes of the anterior segments architecture induced by LPI in AAC eyes. The found threshold values for ACD, ACV, and ACA may help in daily clinical routine to discriminate between healthy eyes and those in need for a prophylactic LPI.

  4. In vitro penetration of bleaching agents into the pulp chamber

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Valera, M C; Mancini, M N G

    2004-01-01

    To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

  5. TOPICAL REVIEW: Negative thermal expansion

    Science.gov (United States)

    Barrera, G. D.; Bruno, J. A. O.; Barron, T. H. K.; Allan, N. L.

    2005-02-01

    There has been substantial renewed interest in negative thermal expansion following the discovery that cubic ZrW2O8 contracts over a temperature range in excess of 1000 K. Substances of many different kinds show negative thermal expansion, especially at low temperatures. In this article we review the underlying thermodynamics, emphasizing the roles of thermal stress and elasticity. We also discuss vibrational and non-vibrational mechanisms operating on the atomic scale that are responsible for negative expansion, both isotropic and anisotropic, in a wide range of materials.

  6. Thermal Expansion of Polyurethane Foam

    Science.gov (United States)

    Lerch, Bradley A.; Sullivan, Roy M.

    2006-01-01

    Closed cell foams are often used for thermal insulation. In the case of the Space Shuttle, the External Tank uses several thermal protection systems to maintain the temperature of the cryogenic fuels. A few of these systems are polyurethane, closed cell foams. In an attempt to better understand the foam behavior on the tank, we are in the process of developing and improving thermal-mechanical models for the foams. These models will start at the microstructural level and progress to the overall structural behavior of the foams on the tank. One of the key properties for model characterization and verification is thermal expansion. Since the foam is not a material, but a structure, the modeling of the expansion is complex. It is also exacerbated by the anisoptropy of the material. During the spraying and foaming process, the cells become elongated in the rise direction and this imparts different properties in the rise direction than in the transverse directions. Our approach is to treat the foam as a two part structure consisting of the polymeric cell structure and the gas inside the cells. The polymeric skeleton has a thermal expansion of its own which is derived from the basic polymer chemistry. However, a major contributor to the thermal expansion is the volume change associated with the gas inside of the closed cells. As this gas expands it exerts pressure on the cell walls and changes the shape and size of the cells. The amount that this occurs depends on the elastic and viscoplastic properties of the polymer skeleton. The more compliant the polymeric skeleton, the more influence the gas pressure has on the expansion. An additional influence on the expansion process is that the polymeric skeleton begins to breakdown at elevated temperatures and releases additional gas species into the cell interiors, adding to the gas pressure. The fact that this is such a complex process makes thermal expansion ideal for testing the models. This report focuses on the thermal

  7. Strategic Complexity and Global Expansion

    DEFF Research Database (Denmark)

    Oladottir, Asta Dis; Hobdari, Bersant; Papanastassiou, Marina

    2012-01-01

    The purpose of this paper is to analyse the determinants of global expansion strategies of newcomer Multinational Corporations (MNCs) by focusing on Iceland, Israel and Ireland. We argue that newcomer MNCs from small open economies pursue complex global expansion strategies (CGES). We distinguish....... The empirical evidence suggests that newcomer MNCs move away from simplistic dualities in the formulation of their strategic choices towards more complex options as a means of maintaining and enhancing their global competitiveness....

  8. Estimates of expansion time scales

    Science.gov (United States)

    Jones, E. M.

    Monte Carlo simulations of the expansion of a spacefaring civilization show that descendants of that civilization should be found near virtually every useful star in the Galaxy in a time much less than the current age of the Galaxy. Only extreme assumptions about local population growth rates, emigration rates, or ship ranges can slow or halt an expansion. The apparent absence of extraterrestrials from the solar system suggests that no such civilization has arisen in the Galaxy.

  9. Repair of isolated double-chambered right ventricle | El Kouache ...

    African Journals Online (AJOL)

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal highpressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ...

  10. Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

    Directory of Open Access Journals (Sweden)

    Peter Križan

    2012-01-01

    Full Text Available In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process.

  11. Commissioning of SLAC SLD 45-Degree Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Eschenburg, Vance O.

    2002-07-19

    The SLD experiment at the Stanford Linear Accelerator Center had a significant gap in its muon tracking coverage, provided by the Warm Iron Calorimeter. Supplemental planes of limited streamer tube chambers were added to improve the coverage in the vicinity of the gap at 0.65 < |cos{theta}| < 0.85. A software effort to upgrade the tracking software for this system is detailed. The commissioning of the forty-five degree chamber region of the SLAC SLD Warm Iron Calorimeter is presented. This task involved the completion of the forty-five degree chamber region geometry for the Warm Iron Calorimeter's fitter and swimmer and the changing of the way multiple scattering effects are treated in the fitter algorithm.

  12. Thermal Vacuum Chamber Repressurization with Instrument Purging

    Science.gov (United States)

    Woronowicz, Michael

    2017-01-01

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

  13. High temperature thrust chamber for spacecraft

    Science.gov (United States)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  14. Anterior chamber collapse syndrome in a koala.

    Science.gov (United States)

    Liddle, Vl; Naranjo, C; Bernays, Me

    2014-05-01

    Anterior chamber collapse syndrome has been recognised in various species and is associated with early-life ocular disease or trauma. It is important to differentiate this acquired condition from a congenital malformation. An adult female koala (Phascolarctos cinereus) was referred for assessment of buphthalmos and severe keratitis of the right eye. The degree of keratitis obstructed examination of intraocular structures. Enucleation of the affected eye was performed and the histopathological diagnosis was anterior chamber collapse syndrome and secondary glaucoma. This case contributes to the limited information available in the literature on anterior chamber collapse syndrome, a disease unique in having secondary glaucoma with minimal or no inflammation. The case also expands the literature available on ocular disease in koalas. More specifically, this is the only reported case of glaucoma, of any aetiology, in the koala. © 2014 Australian Veterinary Association.

  15. Swirl chamber for vitrification of fly ashes

    Directory of Open Access Journals (Sweden)

    Zarzycki Robert

    2017-01-01

    Full Text Available The study presents the concept of a swirl chamber used for vitrification of fly ashes. It assumes the use of coal dust in the process of fly ash melting. The coal dust supplied to the swirl chamber and gasified in the atmosphere of O2, CO2 and H2O allows for obtaining combustible gases composed of CO and H2, which are burnt with the pneumatically supplied fly ash. The above process allows for obtaining a product in the form of a molten slag which does not contain coal grains. The study presents numerical calculations for the process of combustion and gasification of coal dust and opportunities for ensuring adequate parameters in the fly ash melting zone. The combustible gases obtained during the process of gasification can be supplied to the chamber of a pulverized-bed boiler.

  16. Emulsion chamber experiments for the Space Station

    Science.gov (United States)

    Wilkes, R. J.

    Emulsion chambers offer several unique features for the study of ultrahigh-energy cosmic-ray interactions and spectra aboard a permanent manned Space Station. Emulsion-chamber experiments provide the highest acceptance/weight ratio of any current experimental technique, are invulnerable to mechanical shocks and temperature excursions associated with space flight, do not employ volatile or explosive components or materials, and are not dependent upon data communications or recording systems. Space-Station personnel would be employed to replace track-sensitive materials as required by background accumulation. Several emulsion-chamber designs are proposed, including both conventional passive calorimetric detectors and a hybrid superconducting-magnetic-spectrometer system. Results of preliminary simulation studies are presented. Operational logistics are discussed.

  17. Almond Test Body. [for microwave anechoic chambers

    Science.gov (United States)

    Dominek, Allen K. (Inventor); Wood, Richard M. (Inventor); Gilreath, Melvin C. (Inventor)

    1989-01-01

    The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

  18. Sealed Plant-Growth Chamber For Clinostat

    Science.gov (United States)

    Brown, Christopher S.; Dreschel, Thomas W.

    1993-01-01

    Laboratory chamber for growing plants used to measure photosynthesis and respiration in simulated microgravity. Holds plant specimens while rotated on clinostat, see article, "Clinostat Delivers Power To Plant-Growth Cabinets" (KSC-11537). Provides way of comparing gas-exchange rates of plants rotated horizontally on clinostat with those of stationary or vertically rotated plants. Gas extracted for analysis without stopping clinostat. Chamber includes potlike base and cylindrical cover, both made of transparent acrylic pipe. Gasket forms seal between cover and bottom plate of base. Cover bolted to pot baseplate, which in turn bolted to clinostat.

  19. Permeability of MDT chambers to water vapor

    CERN Document Server

    Palestini, S

    2003-01-01

    Tests of MDT chambers performed at the GIF facility and in the H8 test-beam area have shown relative high levels of water vapor contamination in the gas-mixture at the detector output. This effects significantly the drift properties of the MDTs. This note shows that amount of water observed is compatible with approximate estimates based on the permeability of Noryl, used in the tube end-plugs, and of EPDM, used in the O-rings of the on-chamber gas distribution.

  20. A view inside the Gargamelle bubble chamber

    CERN Multimedia

    1970-01-01

    Gargamelle was the name given to a big bubble chamber built at the Saclay Laboratory in France during the late 1960s. It was designed principally for the detection at CERN of the elusive particles called neutrinos. A bubble chamber contains a liquid under pressure, which reveals the tracks of electrically charged particles as trails of tiny bubbles when the pressure is reduced. Neutrinos have no charge, and so leave no tracks, but the aim with Gargamelle was "see neutrinos" by making visible any charged particles set in motion by the interaction of neutrinos in the liquid

  1. Almond test body. [for microwave anechoic chambers

    Science.gov (United States)

    Dominek, Allen K. (Inventor); Wood, Richard M. (Inventor); Gilreath, Melvin C. (Inventor)

    1989-01-01

    The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

  2. Reed's Conjecture on hole expansions

    CERN Document Server

    Fouquet, Jean-Luc

    2012-01-01

    In 1998, Reed conjectured that for any graph $G$, $\\chi(G) \\leq \\lceil \\frac{\\omega(G) + \\Delta(G)+1}{2}\\rceil$, where $\\chi(G)$, $\\omega(G)$, and $\\Delta(G)$ respectively denote the chromatic number, the clique number and the maximum degree of $G$. In this paper, we study this conjecture for some {\\em expansions} of graphs, that is graphs obtained with the well known operation {\\em composition} of graphs. We prove that Reed's Conjecture holds for expansions of bipartite graphs, for expansions of odd holes where the minimum chromatic number of the components is even, when some component of the expansion has chromatic number 1 or when a component induces a bipartite graph. Moreover, Reed's Conjecture holds if all components have the same chromatic number, if the components have chromatic number at most 4 and when the odd hole has length 5. Finally, when $G$ is an odd hole expansion, we prove $\\chi(G)\\leq\\lceil\\frac{\\omega(G)+\\Delta(G)+1}{2}\\rceil+1$.

  3. Drift Chambers detectors; Detectores de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Martinez laso, L.

    1989-07-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

  4. Vacuum chamber for intersection I-4

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Vacuum chamber for intersection I-4 of the ISR being assembled inside a wooden mock-up of the gap of the split-field magnet. The central round-cylinder section is provisional and is to be replaced by an elliptic-cylinder section to give more space vertically for installation of detectors. Supports for the central section are of carbon fibre composite.

  5. Using reverberation chambers for em measurements

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2010-01-01

    Reverberation chambers (RC) are being used for several decades. The main advantage is the high field strength which can be generated, with only modest power. In the last few years the use of RCs became much popular, for testing multi-path propagation for communication links, or testing the coupling

  6. Spark chambers in the Microcosm museum

    CERN Multimedia

    Patrice Loiez

    1990-01-01

    These spark chambers were displayed in CERN's permanent exhibition, Microcosm. These were particle detectors in which the tracks of particles would be seen by sparks created along the particle's path. While touring Microcosm, visitors can learn more about this and other detector methods both past and present.

  7. Intracapsular cataract extraction with anterior chamber intraocular ...

    African Journals Online (AJOL)

    Aim: To assess the visual outcome of cataract extraction with ACIOL implantation in a Nigerian hospital. Methods: The visual outcome of 50 eyes of 42 patients aged 40 years and above, out of 212 eyes that underwent intracapsular cataract extraction (ICCE) and anterior chamber intraocular lens (ACIOL) implantation, were ...

  8. Lifetime tests for MAC vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions. (LEW)

  9. Readout system for proportional wire chambers

    CERN Document Server

    Berst, J D; Metzger, G; Meyer, J M; Schultz, G

    1974-01-01

    The authors describe a MWPC read-out system intended for the hyperon experiments at CERN. Its structure is like the familiar CAMAC branch highway, but driven by a spark chamber readout module placed in CAMAC. The different parts of the equipment, which may read up to 4096 wires, and the test system are described. (5 refs).

  10. IKAR, a ionization chamber for WA9

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    This ionization chamber arrived at CERN from Leningrad for a high precision study of hadron elastic scattering by a CERN-Clermont-Ferrand-Leningrad-Lyon-Uppsala Collaboration in the H3 beam (WA9). G.A. Korolev (third from right) looks at the drawings.

  11. Presenting Chamber Music to Young Children

    Science.gov (United States)

    Smith, Terry Fonda

    2011-01-01

    The number of professional ensembles and organizations with dedicated outreach concerts has been steadily increasing over the past decade. More recently, educational concerts pairing chamber music with young children have been documented. The work presented in this article is a study in the efficacy and feasibility of this format. Various music…

  12. The arrival of the CLOUD chamber

    CERN Multimedia

    CERN AVC

    2009-01-01

    The team from the CLOUD experiment - the world’s first experiment using a high-energy particle accelerator to study the climate - were on cloud nine after the arrival of their new three-metre diameter cloud chamber. This marks the end of three years’ R&D; and design, and the start of preparations for data taking later this year.

  13. Prototype vacuum chamber for ISR intersection region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction regions had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  14. Prototype Vacuum Chamber for ISR Intersection Region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction region had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  15. Reproducibility of the chamber scarification test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1996-01-01

    The chamber scarification test is a predictive human skin irritation test developed to rank the irritation potential of products and ingredients meant for repeated use on normal and diseased skin. 12 products or ingredients can be tested simultaneously on the forearm skin of each volunteer. The t...

  16. The use of microholography in bubble chambers

    CERN Document Server

    Royer, H

    1981-01-01

    In-line holography has been used for the first time in a bubble chamber for the account of the CERN (Geneva, CH). The holograms were recorded with the help of a single-mode pulse laser. Bubble tracks of 25 microns in diameter have been reconstructed with a resolution of 2 microns. (12 refs).

  17. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  18. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  19. Thermal Expansion of Hafnium Carbide

    Science.gov (United States)

    Grisaffe, Salvatore J.

    1960-01-01

    Since hafnium carbide (HfC) has a melting point of 7029 deg. F, it may have many high-temperature applications. A literature search uncovered very little information about the properties of HfC, and so a program was initiated at the Lewis Research Center to determine some of the physical properties of this material. This note presents the results of the thermal expansion investigation. The thermal-expansion measurements were made with a Gaertner dilatation interferometer calibrated to an accuracy of +/- 1 deg. F. This device indicates expansion by the movement of fringes produced by the cancellation and reinforcement of fixed wave-length light rays which are reflected from the surfaces of two parallel quartz glass disks. The test specimens which separate these disks are three small cones, each approximately 0.20 in. high.

  20. Repeated expansion in burn sequela.

    Science.gov (United States)

    Pitanguy, Ivo; Gontijo de Amorim, Natale Ferreira; Radwanski, Henrique N; Lintz, José Eduardo

    2002-08-01

    This paper presents a retrospective study of the use of 346 expanders in 132 patients operated at the Ivo Pitanguy Clinic, between the period of 1985 and 2000. The expanders were used in the treatment of burn sequela. In the majority of cases, more than one expander was used at the same time. In 42 patients, repeated tissue expansion was done. The re-expanded flaps demonstrated good distension and viability. With the increase in area at each new expansion, larger volume expanders were employed, achieving an adequate advancement of the flaps to remove the injured tissue. The great advantage of using tissue re-expansion in the burned patient is the reconstruction of extensive areas with the same color and texture of neighboring tissues, without the addition of new scars.

  1. 18 CFR 154.309 - Incremental expansions.

    Science.gov (United States)

    2010-04-01

    ... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Incremental expansions... incremental facilities to be rolled-in to the pipeline's rates. For every expansion that has an at-risk...

  2. The STREON Recirculation Chamber: An Advanced Tool to Quantify Stream Ecosystem Metabolism in the Benthic Zone

    Science.gov (United States)

    Brock, J. T.; Utz, R.; McLaughlin, B.

    2013-12-01

    ) under various velocity settings. The extent of exchange with the sediment was assessed by means of a saline tracer injection and adjustment using flow-regulating components was explored. Performance under a broad range of temperatures (1 to 30 °C) was assessed. Finally, a novel heat-exchange mechanism meant to minimize warming during operations was evaluated. All prototype assessments demonstrate the applicability of the STREON chamber under a broad range of conditions. Though the STREON recirculation chamber has been designed to satisfy the specific needs of the STREON program, the open-access nature of the NEON network should facilitate scope expansion in the coming decades. The STREON recirculation chamber design and all prototype testing data will be accessible to facilitate chamber use elsewhere. The large number of chamber assemblies required for STREON operations should facilitate the acquisition of units by researchers working outside of the NEON network. Furthermore, the current scope of STREON includes the use of the chambers only once annually, thus a valuable tool for stream ecosystem measurements will be readily available at STREON sites for potential use by researchers interested in such measurements.

  3. A Cosmic Ray Measurement Facility for ATLAS Muon Chambers

    CERN Document Server

    Biebel, O; Boutemeur, M; Brandt, A; Dubbert, J; Duckeck, G; Elmsheuser, J; Fiedler, F; Hertenberger, R; Kortner, O; Nunnemann, T; Rauscher, F; Schaile, A D; Schieferdecker, P; Staude, A; Stiller, W; Ströhmer, R; Vertesi, R

    2003-01-01

    Monitored Drift Tube (MDT) chambers will constitute the large majority of precision detectors in the Muon Spectrometer of the ATLAS experiment at the Large Hadron Collider at CERN. For commissioning and calibration of MDT chambers, a Cosmic Ray Measurement Facility is in operation at Munich University. The objectives of this facility are to test the chambers and on-chamber electronics, to map the positions of the anode wires within the chambers with the precision needed for standalone muon momentum measurement in ATLAS, and to gain experience in the operation of the chambers and on-line calibration procedures. Until the start of muon chamber installation in ATLAS, 88 chambers built at the Max Planck Institute for Physics in Munich have to be commissioned and calibrated. With a data taking period of one day individual wire positions can be measured with an accuracy of 8.3 micrometers in the chamber plane and 27 micrometers in the direction perpendicular to that plane.

  4. Towards an optimal concept for numerical codes simulating thrust chamber processes in high pressure chemical propulsion systems

    Science.gov (United States)

    Schley, Clive-Axel; Hagemann, Gerald; Krülle, Gerd

    1996-02-01

    Modelling aspects for rocket engines, where propellants are burned at high pressures to achieve a maximum of performance, are discussed. Concentrating on combustion chamber and expansion nozzle, critical flow phenomena are identified. Physical models for these phenomena with regard to numerical simulations are presented. Different numerical procedures are analyzed concerning their advantages and disadvantages being applied for cryogenic high performance thrust chamber simulations. The application of some of these models is shown exemplary for a 3D multi-injector combustion chamber and the flowfield computation of a plug nozzle concept to present capabilities, limitations and prospects of CFD in this area. Finally, remarks on verification of numerical schemes with regard to the individual physical, chemical and numerical models are given.

  5. Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

    Directory of Open Access Journals (Sweden)

    A Sahap Kükner

    2014-01-01

    Full Text Available We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL in the anterior chamber (AC with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

  6. Efficient computation of coherent synchrotron radiation in a rectangular chamber

    Directory of Open Access Journals (Sweden)

    Robert L. Warnock

    2016-09-01

    Full Text Available We study coherent synchrotron radiation (CSR in a perfectly conducting vacuum chamber of rectangular cross section, in a formalism allowing an arbitrary sequence of bends and straight sections. We apply the paraxial method in the frequency domain, with a Fourier development in the vertical coordinate but with no other mode expansions. A line charge source is handled numerically by a new method that rids the equations of singularities through a change of dependent variable. The resulting algorithm is fast compared to earlier methods, works for short bunches with complicated structure, and yields all six field components at any space-time point. As an example we compute the tangential magnetic field at the walls. From that one can make a perturbative treatment of the Poynting flux to estimate the energy deposited in resistive walls. The calculation was motivated by a design issue for LCLS-II, the question of how much wall heating from CSR occurs in the last bend of a bunch compressor and the following straight section. Working with a realistic longitudinal bunch form of r.m.s. length 10.4  μm and a charge of 100 pC we conclude that the radiated power is quite small (28 W at a 1 MHz repetition rate, and all radiated energy is absorbed in the walls within 7 m along the straight section.

  7. Achievable field strength in reverberation chambers

    Directory of Open Access Journals (Sweden)

    N. Eulig

    2003-01-01

    Full Text Available Feldvariable Kammern (FVK, engl.: modestirred- chamber werden unter anderem für EMV-Störfestigkeitsprüfungen verwendet. Ein häufig genanntes Argument, das die Einführung dieser Kammern als normgerechte Prüfumgebung vorantreiben soll, ist eine hohe Feldstärke, die im Vergleich zu anderen Testumgebungen mit relativ moderaten HF-Leistungen erreicht werden kann. Besonders für sicherheitskritische Geräte, wie Komponenten aus der Avionik- oder KFZ-Industrie, sind heutzutage Testfeldstärken von mehreren 100 V/m notwendig. Derart hohe Feldstärken können in Umgebungen, die ein ebenes Wellenfeld erzeugen oder nachbilden, nur mit großen HFLeistungen generiert werden. Durch die Resonanzeigenschaften einer FVK können demgegenüber mit sehr viel weniger Leistung und damit Verstärkeraufwand vergleichbare Werte der Feldstärke erzeugt werden. Allerdings sinkt mit zunehmendem Volumen die erreichbare Feldstärke bei gleicher Speiseleistung. Idealerweise sollen Feldvariable Kammern bei möglichst niedrigen Frequenzen für EMVTests nutzbar sein, was jedoch ein großes Kammervolumen erfordert. Das Problem, bei niedrigen Frequenzen hohe Feldstärken erzeugen zu können, relativiert deshalb den Vorteil von FVKn gegenüber bekannten Testumgebungen bei niedrigen Testfrequenzen. Der Posterbeitrag erläutert, welche Feldstärken in verschieden großen Feldvariablen Kammern beim Einspeisen einer bestimmten hochfrequenten Leistung erreicht werden können. Anhand dieser Ergebnisse wird aufgezeigt, oberhalb welcher Grenzfrequenz eine Anwendung von FVKn nur sinnvoll erscheint. Mode-stirred chambers (MSCs can be used for radiated immunity tests in EMC testing. Advantageous compared to conventional test methods is the high field strength which can here be generated with less RF-Power. This point is often the main argument for pushing the standardization of MSCs as an other EMC testing environment. Especially for safety-critical electronic equipment like avionic or

  8. Low-thermal expansion infrared glass ceramics

    Science.gov (United States)

    Lam, Philip

    2009-05-01

    L2 Tech, Inc. is in development of an innovative infrared-transparent glass ceramic material with low-thermal expansion (ZrW2O8) which has Negative Thermal Expansion (NTE). The glass phase is the infrared-transparent germanate glass which has positive thermal expansion (PTE). Then glass ceramic material has a balanced thermal expansion of near zero. The crystal structure is cubic and the thermal expansion of the glass ceramic is isotropic or equal in all directions.

  9. RAPID COMMUNICATION: Conducting triangular chambers for EMC measurements

    Science.gov (United States)

    Huang, Yi

    1999-03-01

    Conducting rectangular chambers have been used extensively for electromagnetic compatibility (EMC) shielding and measurement applications. In this communication, conducting triangular chambers are investigated as an alternative structure for rectangular EMC reverberation chambers, which are becoming an increasingly important and powerful tool for both radiated immunity and emission tests. A prime consideration of designing such a system is the total possible number of modes inside the chamber. A new approach is introduced to obtain this parameter for three different triangular chambers. The initial study has demonstrated that triangular chambers may offer better performance in some cases than their rectangular counterparts.

  10. Metallic spherical anechoic chamber for antenna pattern measurement

    Science.gov (United States)

    Farahbakhsh, Ali; Khalaj-Amirhosseini, Mohammad

    2016-08-01

    Anechoic chambers are used for indoor antenna measurements. The common method of constructing an anechoic chamber is to cover all inside walls by the electromagnetic absorbers. In this paper, a fully metallic spherical chamber structure is presented in which the propagation of the electromagnetic waves inside the chamber is controlled and they are guided to an absorber. In the proposed method, an appropriate quiet zone is obtained, and unlike ordinary anechoic chambers, the absorber usage amount is reduced greatly. The performance of the chamber is evaluated by simulation. The results show that the proposed method could provide a useful technique for the indoor antenna measurements.

  11. Expansive Openness in Teacher Practice

    Science.gov (United States)

    Kimmons, Royce

    2016-01-01

    Background/Context: Previous work on the use of open educational resources in K-12 classrooms has generally focused on issues related to cost. The current study takes a more expansive view of openness that also accounts for adaptation and sharing in authentic classroom contexts. Purpose/Objective/Research Question/Focus of Study The study seeks to…

  12. On Fourier re-expansions

    OpenAIRE

    Liflyand, E.

    2012-01-01

    We study an extension to Fourier transforms of the old problem on absolute convergence of the re-expansion in the sine (cosine) Fourier series of an absolutely convergent cosine (sine) Fourier series. The results are obtained by revealing certain relations between the Fourier transforms and their Hilbert transforms.

  13. On persistently positively expansive maps

    Directory of Open Access Journals (Sweden)

    Alexander Arbieto

    2010-06-01

    Full Text Available In this paper, we prove that any C¹-persistently positively expansive map is expanding. This improves a result due to Sakai (Sakai 2004.Neste artigo, mostramos que todo mapa C¹-persistentemente positivamente expansivo e expansor. Isto melhora um resultado devido a Sakai (Sakai 2004.

  14. The bootstrap and edgeworth expansion

    CERN Document Server

    Hall, Peter

    1992-01-01

    This monograph addresses two quite different topics, in the belief that each can shed light on the other. Firstly, it lays the foundation for a particular view of the bootstrap. Secondly, it gives an account of Edgeworth expansion. Chapter 1 is about the bootstrap, witih almost no mention of Edgeworth expansion; Chapter 2 is about Edgeworth expansion, with scarcely a word about the bootstrap; and Chapters 3 and 4 bring these two themes together, using Edgeworth expansion to explore and develop the properites of the bootstrap. The book is aimed a a graduate level audience who has some exposure to the methods of theoretical statistics. However, technical details are delayed until the last chapter (entitled "Details of Mathematical Rogour"), and so a mathematically able reader without knowledge of the rigorous theory of probability will have no trouble understanding the first four-fifths of the book. The book simultaneously fills two gaps in the literature; it provides a very readable graduate level account of t...

  15. Multiscale expansions in discrete world

    Indian Academy of Sciences (India)

    ... multiscale expansions discretely. The power of this manageable method is confirmed by applying it to two selected nonlinear Schrödinger evolution equations. This approach can also be applied to other nonlinear discrete evolution equations. All the computations have been made with Maple computer packet program.

  16. Large N Expansion. Vector Models

    OpenAIRE

    Nissimov, Emil; Pacheva, Svetlana

    2006-01-01

    Preliminary version of a contribution to the "Quantum Field Theory. Non-Perturbative QFT" topical area of "Modern Encyclopedia of Mathematical Physics" (SELECTA), eds. Aref'eva I, and Sternheimer D, Springer (2007). Consists of two parts - "main article" (Large N Expansion. Vector Models) and a "brief article" (BPHZL Renormalization).

  17. An uncommon variant of double-chambered right ventricle masquerading as double-chambered left ventricle.

    Science.gov (United States)

    Baritakis, Nikolaos; Grapsas, Nikolaos; Kotsalos, Andreas; Davlouros, Periklis

    2018-02-01

    We present a rare case of a double-chambered right ventricle masquerading as a double-chambered left ventricle, which was found incidentally on cardiac imaging in an adult female patient with atypical chest pain. The most common form of double-chambered right ventricle is characterized by compartmentalization of the right ventricle by muscular bands into 2 distinct chambers. The main features of this malformation are a pressure gradient between the 2 compartments, and the frequent (up to 90%) association with a membranous ventricular septal defect. In our case, the muscular band dividing the right ventricle was located in the inferoseptal part of the latter, creating a diminutive cavity that had no communication with the main right ventricle but communicated with the left ventricle creating the false impression of a double-chambered left ventricle. This constitutes a rare variant of double-chambered right ventricle with unknown clinical implications. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  18. Effective Expansion: Balance between Shrinkage and Hygroscopic Expansion.

    Science.gov (United States)

    Suiter, E A; Watson, L E; Tantbirojn, D; Lou, J S B; Versluis, A

    2016-05-01

    The purpose of this study was to investigate the relationship between hygroscopic expansion and polymerization shrinkage for compensation of polymerization shrinkage stresses in a restored tooth. One resin-modified glass-ionomer (RMGI) (Ketac Nano, 3M ESPE), 2 compomers (Dyract, Dentsply; Compoglass, Ivoclar), and a universal resin-based composite (Esthet•X HD, Dentsply) were tested. Volumetric change after polymerization ("total shrinkage") and during 4 wk of water storage at 37°C was measured using an optical method (n= 10). Post-gel shrinkage was measured during polymerization using a strain gauge method (n= 10). Extracted human molars with large mesio-occluso-distal slot preparations were restored with the tested restorative materials. Tooth surfaces at baseline (preparation), after restoration, and during 4 wk of 37°C water storage were scanned with an optical scanner to determine cuspal flexure (n= 8). Occlusal interface integrity was measured using dye penetration. Data were analyzed using analysis of variance and post hoc tests (significance level 0.05). All tested materials shrunk after polymerization. RMGI had the highest total shrinkage (4.65%) but lowest post-gel shrinkage (0.35%). Shrinkage values dropped significantly during storage in water but had not completely compensated polymerization shrinkage after 4 wk. All restored teeth initially exhibited inward (negative) cuspal flexure due to polymerization shrinkage. Cuspal flexure with the RMGI restoration was significantly less (-6.4 µm) than with the other materials (-12.1 to -14.1 µm). After 1 d, cuspal flexure reversed to +5.0 µm cuspal expansion with the RMGI and increased to +9.3 µm at 4 wk. After 4 wk, hygroscopic expansion compensated cuspal flexure in a compomer (Compoglass) and reduced flexure with Dyract and resin-based composite. Marginal integrity (93.7% intact restoration wall) was best for the Compoglass restorations and lowest (73.1%) for the RMGI restorations. Hygroscopic

  19. The physics of Resistive Plate Chambers

    CERN Document Server

    Riegler, Werner

    2004-01-01

    Over the last 3 years we investigated theoretical aspects of Resistive Plate Chambers (RPC) in order to clarify some of the outstanding questions on space charge effects, high efficiency of small gap RPCs, charge spectra, signal shape and time resolution. In a series of reports we analyzed RPC performance including all detector aspects covering primary ionization, avalanche multiplication, space charge effects, signal induction in presence of resistive materials, crosstalk along detectors with long strips and front-end electronics. Using detector gas parameters entirely based on theoretical predictions and physical models for avalanche development and space charge effects we are able to reproduce measurements for 2 and 0.3 mm RPCs to very high accuracy without any additional assumptions. This fact gives a profound insight into the workings of RPCs and also underlines the striking difference in operation regime when compared to wire chambers. A summary of this work as well as recent results on three-dimensiona...

  20. Introduction for Diffusion Chamber Culture Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Carsten, A. L.

    1979-01-01

    The diffusion-chamber system has been applied to studies of cell kinetics, progenitor cell quantitation, humoral effects, immunological effects, cytogenetics, organogenesis, and the cellular effects of drugs and physical factors such as radiation, hypoxia, etc. Chamber contents have been analyzed by clot dissolution with measuring of cell content, limiting dilution evaluation, radionuclide utilization (tritiated thymidine labeling), growth of colony number, size and type, CFU-S or CFU-C content, or proliferation by secondary culture in mice or in vitro systems, and chromosome changes. Cell types ranging from embryonal tissues to adult normal and neoplastic tissues have been grown in hosts across species barriers. Advantages and disadvantages of this system are discussed.

  1. The KLOE drift chamber VCI 2001

    CERN Document Server

    Adinolfi, M; Ambrosino, F; Andryakov, A; Antonelli, A; Antonelli, M; Anulli, F; Bacci, C; Bankamp, A; Barbiellini, G; Bellini, F; Bencivenni, G; Bertolucci, Sergio; Bini, C; Bloise, C; Bocci, V; Bossi, F; Branchini, P; Bulychjov, S A; Cabibbo, G; Calcaterra, A; Caloi, R; Campana, P; Capon, G; Carboni, G; Cardini, A; Casarsa, M; Cataldi, G; Ceradini, F; Cervell, F; Cevenini, F; Chiefari, G; Ciambrone, P; Conetti, S; Conticelli, S; De Lucia, E; De Robertis, G; De Simone, P; De Zorzi, G; De Sangro, R; Dell'Agnello, S; Denig, A; Di Domenico, A; Di Donato, C; Di Falco, S; Doria, A; Drago, E; Elia, V; Erriquez, O; Farilla, A; Felici, G; Ferrari, A; Ferrer, M L; Finocchiaro, G; Forti, C; Franceschi, A; Franzini, P; Gao, M L; Gatti, C; Gauzzi, P; Giovannella, S; Golovatyuk, V; Gorini, E; Grancagnolo, F; Grandegger, W; Graziani, E; Guarnaccia, P; Han, H G; Han, S W; Huang, X; Incagli, M; Ingrosso, L; Jang, Y Y; Kim, W; Kluge, W; Kulikov, V; Lacava, F; Lanfranchi, G; Lee-Franzini, J; Lomtadze, F; Luisi, C; Mao Chen Sheng; Martemyanov, M; Matsyuk, M; Mei, W; Merola, L; Messi, R; Miscetti, S; Moalem, A; Moccia, S; Moulson, M; Murtas, F; Müller, S; Napolitano, M; Nedosekin, A; Pacciani, L; Pagès, P; Palutan, M; Panareo, M; Paoluzi, L; Pasqualucci, E; Passalacqua, L; Passaseo, M; Passeri, A; Patera, V; Petrolo, E; Petrucci, Guido; Picca, D; Pirozzi, G; Pistillo, C; Pollack, M; Pontecorvo, L; Primavera, M; Ruggieri, F; Santangelo, P; Santovetti, E; Saracino, G; Schamberger, R D; Schwick, C; Sciascia, B; Sciubba, A; Scuri, F; Sfiligoi, I; Shan, J; Silano, P; Spadaro, T; Spagnolo, S; Spiriti, E; Stanescu, C; Tong, G L; Tortora, L; Valente, E; Valente, P; Valeriani, B; Venanzoni, G; Veneziano, Stefano; Von Hagel, U; Wu, Y; Xie, Y G; Zhao, P P; Zhou, Y

    2002-01-01

    The main goal of the KLOE experiment at the Frascati DAPHINE phi-factory is the study CP violation in kaon decays. The tracking device of the experiment is a drift chamber whose dimensions, 4 m of diameter and 3.3 m length, provide a large acceptance volume for the decay products of low momentum K sub L (lambda sub L =3.4 m). A complete stereo geometry with 12.582 cells arranged in 58 layers guarantees a high and uniform efficiency in the reconstruction of the charged K sub L decays. Very light materials have been chosen both for the drift medium, a helium-based gas mixture, and for the mechanical structure, made of carbon fiber, to minimize multiple scattering and conversion of low-energy photons. The design requirements, the adopted solutions together with the calibration procedure and the tracking performances of the drift chamber are discussed.

  2. Diurnal variations in a sealed radon chamber

    Science.gov (United States)

    Gilboy, W. B.; James, P. R.; Farmer, C. P.; Beard, J. E.

    1990-12-01

    During experiments to calibrate a radon-in-air counter, some unexpected diurnal variations have been observed. Inside the sealed stainless-steel chamber of a nominal volume of 3 litres, ionised 218Po atoms from the alpha-decay of 222Rn are attracted by an electric field to a ZnS(Ag) scintillation screen via which subsequent α-decay events are detected. Results for this configuration are presented and also for a modified version in which the scintillation screen is replaced by a high-resolution α-detector. Ambient temperature changes were suspected to be responsible for the observed counting-efficiency variation and this has been confirmed by operating the wall of the chamber at various temperatures between 0°C and about 40°C, which revealed a positive temperature coefficient of ˜1%/°C at 25°C. Possible reasons for this effect are considered.

  3. Wire chambers with their magnetostrictive readout

    CERN Multimedia

    1974-01-01

    This set of wire chamber planes shaped as a cylinder sector was installed inside the magnet of a polarized spin target modified to allow as well momentum analysis of the produced particles. The experiment (S126) was set up by the CERN-Trieste Collaboration in the PS beam m9 to measure spin effects in the associated production of of a positive kaon and a positive Sigma by interaction of a positive pion with polarized protons.

  4. The Bern Infinitesimal Bubble Chamber (BIBC)

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The chamber body was machined from a block of aluminium. The visible volume was cylindrical with 65 mm diameter and 35 mm depth. It was filled with propane or freon. It was meant as vertex detector in the search of short-lived particles. It was also used with in-line holography resulting in 8 µm bubble size and 9 cm depth of the field. See E. Ramseyer, B. Hahn and E. Hugentobler, Nucl. Instrum. Methods 201 (1982) 335.

  5. Efficient Determination of Reverberation Chamber Time Constant

    OpenAIRE

    Zhang, Xiaotian; Robinson, Martin P.; Flintoft, Ian D.; Dawson, John F.

    2017-01-01

    Determination of the rate of energy loss in a reverberation chamber is fundamental to many different measurements such as absorption cross-section, antenna efficiency, radiated power, and shielding effectiveness. Determination of the energy decay time-constant in the time domain by linear fitting the power delay profile, rather than using the frequency domain quality-factor, has the advantage of being independent of the radiation efficiency of antennas used in the measurement. However, determ...

  6. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    To minimise eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical strength, it was corrugated in a hydro-forming process. The cross-section was designed for maximum strength and maximum aperture. To accept particles with simultaneous large amplitudes in both planes, the cross-section approaches a rectangular shape (see also 7402463).

  7. Cell seeding chamber for bone graft substitutes

    OpenAIRE

    Hennig, J.; Schieker, Matthias; Seitz, H.

    2012-01-01

    There is an increasing demand for bone graft substitutes that are used as osteoconductive scaffolds in the treatment of bone defects and fractures. Achieving optimal bone regeneration requires initial cell seeding of the scaffolds prior to implantation. The cell seeding chamber is a closed assembly. It works like a sandglass. The position of the scaffold is between two reservoirs containing the fluid (e. g. blood). The fluid at the upper reservoir flows through the scaffold driven by gravity....

  8. Diurnal Variation of Anterior Chamber Flare

    Directory of Open Access Journals (Sweden)

    Mehmet Adam

    2015-04-01

    Full Text Available Objectives: To investigate the ideal time and reproducibility of anterior chamber flare measurements. Materials and Methods: Anterior chamber flare measurements were performed with laser flaremetre device at 8 am to 45 volunteers and these measurements were repeated on the same day at 12 pm and 4 pm. Results: Twenty-five (55.5% of the volunteers were women and 20 (44.5% were men; mean age was 28.67±7.40 (18-49 years. The mean anterior chamber flare measurements taken following the ophthalmologic examination were 5.94±1.41 foton/msn at 8 am, 5.65±1.45 foton/msn at 12 pm, and 5.79±1.20 foton/msn at 4 pm. No statistical difference was found between the measurements (p=0.08. Subgroup analysis according to eye color, revealed no significant difference between flare measurements in brown, hazel, and green eyes (p=0.21. Correlation analysis demonstrated association between age and all flare measurements within the day (r=0.24, p=0.03; r=0.41, p=0.01, r=0.27, p=0.01. Conclusion: No significant diurnal change was detected in the flare measurements of our study subjects but positive correlation with age was observed. Hence, all flare measurements within a day are reliable and have high repeatability in healthy subjects. (Turk J Ophthalmol 2015; 45: 52-5

  9. Close cathode chamber: Low material budget MWPC

    Science.gov (United States)

    Varga, Dezső; Kiss, Gábor; Hamar, Gergő; Bencédi, Gyula

    2013-01-01

    Performance of asymmetric-type MWPC-s are presented. In this structure, referred to as Close Cathode Chamber in an earlier study, the material budget is significantly reduced on one hand by the elimination of external support frame, on the other hand by thin detector walls. In this paper it is demonstrated that the outline is compatible with large size detectors (1 m wire length), maintaining mechanical and operation stability, with total weight of 3 kg (including support structure) for a half square meter surface. The detection efficiency and response time is shown to be sufficient for L0 triggering in the ALICE VHMPID layout. Reduced sensitivity to cathode deformations (due to internal overpressure as mechanical strain) is directly demonstrated. On small sized chambers, improvement of position resolution with analog readout is evaluated, reaching 0.09 mm RMS with 2 mm wide cathode segments. Simulation results on signal time evolutions are presented. With the above studies, comparison of classical MWPC-s and the Close Cathode Chamber design is performed in all major aspects.

  10. Menstrual history in altitude chamber trainees.

    Science.gov (United States)

    Schirmer, J U; Workman, W T

    1992-07-01

    Previous studies have determined a higher rate of altitude-induced decompression sickness (DCS) in women than in men. Women are reportedly at higher risk for developing DCS during menses. A study of menstrual history in women completing altitude chamber training without developing DCS has never been accomplished. The purpose of this study was to collect and analyze menstrual history in these women. Thirteen U.S. Air Force Aerospace Physiology Units participated in a USAF-approved survey for 1 year. After completing altitude chamber flights, data on age, day of menstrual cycle (DMC), birth control pill use (BCP), and mean durations of menstrual cycle and menses were collected. There were 508 responses analyzed. There was no differences between mean duration of menstrual cycle and menses in the Yes (Y) and No (N) BCP groups. Y and N BCP groups were equally distributed across the menstrual cycle. Women completing altitude chamber training without developing DCS appear to be evenly distributed across their menstrual cycle, with use of BCPs not affecting their susceptibility to DCS.

  11. Wire pad chamber for LHCb muon system

    CERN Document Server

    Botchine, B; Lazarev, V A; Sagidova, N; Vorobev, A P; Vorobyov, A; Vorobyov, Alexei

    2000-01-01

    2000-003 Wire pad chambers (WPC) have been proposed for the outer Region 4 of the LHCb Muon System. These are double gap MWPCs with small wire spacing allowing to obtain 99% detection efficiency in a 20 ns time window. The chambers have a rectangular shape with the vertical dimension from 20 cm in Station 1 to 30 cm in Station 5. The horizontal dimensions will be different with the maximal size of 3 meters in Station 5. The wires are in the vertical direction. The short wire length allows to use small wire spacing needed for high time resolution. Also, this helps to obtain the uniform gas gain over the whole chamber area. The WPC has one row of the wire pads formed by grouping wires in separate readout channels. Four WPC prototypes have been built at PNPI and tested in the PS beam at CERN. Here we report on the results from these tests. Also, the results of simulation of the WPC performance are presented.

  12. Testing fireproof materials in a combustion chamber

    Directory of Open Access Journals (Sweden)

    Kulhavy Petr

    2017-01-01

    Full Text Available This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time. Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results – i.e. thermal distribution inside and heat release rate that has gone through the sample.

  13. Testing fireproof materials in a combustion chamber

    Science.gov (United States)

    Kulhavy, Petr; Martinec, Tomas; Novak, Ondrej; Petru, Michal; Srb, Pavel

    This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free) and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time). Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

  14. RF Anechoic Chambers, Tri-Service Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — In collaboration with the Navy, there are 12 RF Anechoic and static free exposure chambers located at TSRL. These chambers cover the majority of the RF spectrum and...

  15. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  16. Anechoic chamber in industrial plants. [construction materials and structural design

    Science.gov (United States)

    Halpert, E.; Juncu, O.; Lorian, R.; Marfievici, D.; Mararu, I.

    1974-01-01

    A light anechoic chamber for routine acoustical measurements in the machine building industry is reported. The outer housing of the chamber consists of modules cast in glass fiber reinforced polyester resin; the inner housing consists of pyramidal modules cut out of sound absorbing slates. The parameters of this anechoic chamber facilitate acoustical measurements according to ISO and CAEM recommendations.

  17. The HERMES forward tracking chambers construction, operation, and aging effects

    CERN Document Server

    Brack, J T; Clark, S; Ely, J; Fox, B; Hofman, G J; Kinney, E R; Mercer, D J; Rakness, G; Ristinen, R A; Smythe, W R; Warner, D

    2001-01-01

    The design, construction and operation of the HERMES forward (front) tracking chambers and associated electronics are described. Resolution and limited aging tests have been performed on these drift chambers, which use an Ar/CF sub 4 /CO sub 2 (90 : 5 : 5) gas mixture. No degradation in chamber performance has been observed for a cumulative charge in excess of 9 C/cm.

  18. A cylindrical drift chamber with azimuthal and axial position readout

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M. [Massachusetts Univ., North Dartmouth, MA (United States)]|[Brookhaven National Laboratory, Upton, L.I., NY 11973 (United States)]|[Indiana University, Bloomington, IN 47405 (United States)]|[Institute for High Energy Physics, Protvino (Russian Federation)]|[Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)]|[University of Notre Dame, Notre Dame, IN 46556 (United States)]|[Northwestern University, Evanston, IL 60208 (United States)]|[Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    1997-02-21

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in {pi}{sup -}p interactions. We describe the chamber`s design considerations, details of its construction, electronics, and performance characteristics. (orig.).

  19. 7 CFR 58.423 - Cheese vacuumizing chamber.

    Science.gov (United States)

    2010-01-01

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

  20. Test of an undulated vacuum chamber for the ISR

    CERN Multimedia

    1975-01-01

    This picture shows mechanical tests of an undulated vacuum chamber for downstream arms of ISR intersections. This chamber, made of 0.3 mm thick inconel, had inner dimensions of 150 mm by 50 mm. The deflection under vacuum is measured by dial gauges. On the left one sees the large vessel where vacuum chambers were tested at pressures above atmospheric pressure.

  1. Bi-cone vacuum chamber in the ISR

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The "bi-cone" vacuum chamber in ISR intersection I-7, for experiment R702. Made from 0.28 mm thick titanium, it was at its time the most transparent chamber ever built. Ian Wilson is standing next to the chamber. See also 7609219.

  2. Central Drift Chamber for rare kaon decay spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Cresswell, J.; Numao, T.

    1986-02-01

    Design of the Central Drift Chamber for BNL experiment 787 and measurement of a rare kaon decay are discussed. A jet chamber type cell with 6 sense wires and no interspersed field wires has been designed to achieve good spatial resolution and efficiency in a 1 T magnetic field. Results of the testing of a prototype chamber are presented.

  3. Installation and Commissioning of the new GLM Implantation Chamber

    CERN Document Server

    Pohl, Christoph

    2016-01-01

    Summer student report about the work with the new implantation chamber for the GLM branch of ISOLDE. In the context of this project an API for the vacuum system of the new chamber was developed and implemented in web application that will be used to control the new implantation chamber at some point.

  4. 30 CFR 56.7807 - Flushing the combustion chamber.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Flushing the combustion chamber. 56.7807 Section 56.7807 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Rotary Jet Piercing Rotary Jet Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber...

  5. 30 CFR 57.7807 - Flushing the combustion chamber.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Flushing the combustion chamber. 57.7807... and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be...

  6. Engineering analyses of large precision cathode strip chambers for GEM

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, J.A.; Belser, F.C.; Pratuch, S.M.; Wuest, C.R. [Lawrence Livermore National Lab., CA (United States); Mitselmakher, G. [Superconducting Super Collider Lab., Dallas, TX (United States); Gordeev, A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Johnson, C.V. [Lawrence Livermore National Lab., CA (United States)]|[Superconducting Super Collider Lab., Dallas, TX (United States); Polychronakos, V.A. [Brookhaven National Lab., Upton, NY (United States); Golutvin, I.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1993-10-21

    Structural analyses of large precision cathode strip chambers performed up to the date of this publication are documented. Mechanical property data for typical chamber materials are included. This information, originally intended to be an appendix to the {open_quotes}CSC Structural Design Bible,{close_quotes} is presented as a guide for future designers of large chambers.

  7. Safety observation of applying anterior chamber gas injection for unstable anterior chamber at the end of cataract surgery

    National Research Council Canada - National Science Library

    Yong-Zhi Huang; Tao Sun; Yu-Ting Zhi; Li Li; Lu-Ning Yan

    2015-01-01

    AIM: To observe the surgical effect, complications and assess the safety of applying anterior chamber injection of sterile air to treat instability of anterior chamber occurred at the end of cataract...

  8. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    , and has a range of ecosystem effects where it occurs. Shrub expansion has to a large extend been attributed to increasing temperatures over the past century, while grazing and human disturbance have received less attention. Alnus viridis ssp. crispa is a common arctic species that contributes...... including only undisturbed sites. Shrub cover increased most on E and SE facing slopes, in sites with stable substrate, in areas characterised by human disturbance and in areas without muskoxen grazing. Aspect and human disturbances had the strongest effect on shrub expansion, followed by muskoxen...... locations. A. viridis represents an interesting case to study these effects. SW Greenland is a subarctic to low-arctic region with only limited increases in temperatures during the past decades, and observed climate trends being largely dependent on the observation period. In this region there is limited...

  9. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    of firewood collection. A delayed reaction to the ending of the little ice age cannot be excluded, but seems rather unlikely considering other studies from Greenland. Effects of global warming in SW Greenland must be studied over even longer time periods than the 120 years of the current study. To answer......, and has a range of ecosystem effects where it occurs. Shrub expansion has to a large extend been attributed to increasing temperatures over the past century, while grazing and human disturbance have received less attention. Alnus viridis ssp. crispa is a common arctic species that contributes...... by factors like grazing and human disturbance; II. which climatic factors control shrub growth in SW Greenland and whether these have improved sufficiently over the past century to allow shrub expansion; III. whether growth of A. viridis is promoted by experimental warming; IV. and whether plant genotypes...

  10. RELIABILITY OF LENTICULAR EXPANSION COMPENSATORS

    Directory of Open Access Journals (Sweden)

    Gabriel BURLACU,

    2011-11-01

    Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator

  11. A combination drift chamber/pad chamber for very high readout rates

    Energy Technology Data Exchange (ETDEWEB)

    Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W. [Fermi National Accelerator Lab., Batavia, IL (United States); Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J. [Wisconsin Univ., Madison, WI (United States); Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P. [Pavia Univ. (Italy)]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Arenton, M.; Conetti, S.; Cox, B.; Dukes, E.; Golovatyuk, V.; Hanlet, P.; McManus, A.; Nelson, K.; Recagni, M.; Segal, J.; Sun, J. [Virginia Univ., Charlottesville, VA (United States); Ballagh, C.; Bingham, H.; Kaeding, T.; Lys, J.; Misawa, S. [California Univ., Berkeley, CA (United States); Blankman, A.; Borodin, S.; Kononenko, W.; Newcomer, M.; Selove, W.; Trojak, T.; VanBerg, R.; Zhang, S.N. [Pennsylvania Univ., Philadelphia, PA (United States); Block, M.; Corti, G.; LeCompte, T.; Rosen, J.; Yao, T. [Northwestern Univ., Evanston, IL (United States); Boden, A.; Cline, D.; Ramachandran, S.; Rhoades, J.; Tokar, S. [California Univ., Los Angeles, CA (United States); Budagov, J.; Tsyganov, E. [Joint Inst. for Nuclear Research, Dubna (USSR); Cao, Z.L.; He, M.; Wang, C.; Wei, C.; Zhang, N. [Shandong Univ., Jinan, SD (China); Chen, T.Y.; Yao, N. [Nanjing Univ., JS (China); Clark, K.; Jenkins, M. [University of South Alabama, Mobile, AL (United States); Cooper, M. [Vanier Inst. of the Family, Ottawa, ON (Canada); Creti, P.; Gorini, E.; Grancagnolo, F.; Panareo, M. [Lecce Univ. (Italy)]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy); Fortney, L.; Kowald, W. [Duke Univ., Durham, NC (United States); Haire, M.; Judd, D.; Turnbull, L.; Wagoner, D. [Texas A and M Univ., Prairie View, TX (United States); Lau, K.; Mo, G. [Houston Univ., TX (United States); Trischuk, J. [McGill Univ., Montreal, PQ (Canada)

    1991-11-01

    Six medium-sized ({approx}1 {times} 2 m{sup 2}) drift chambers with pad and stripe readout have been constructed for and are presently operating in Fermi National Accelerator Laboratory experiment E-771. Each chamber module actually represents a pair of identical planes: two sets of anode wires, two sets of stripes, and two sets of pads. The wire planes are read out separately and represent X measurements in the coordinate system of the experiment. The twin stripe and pad planes are internally paired within the chamber modules; stripe signals represent Y measurements and pad signals combination X and Y measurements. Signals which develop on the stripes and pads are mirror (but inverted) images of what is seen on the wires. In addition to being used in the off-line pattern recognition, pad signals are also used as inputs to an on-line high transverse momentum (pt) trigger processor. While the techniques involved in the design and construction of the chambers are not novel, they may be of interest to experiments contemplating very large area, high rate chambers for future spectrometers.

  12. A novel non invasive measurement of hemodynamic parameters: Comparison of single-chamber ventricular and dual-chamber pacemaker

    Directory of Open Access Journals (Sweden)

    Ingrid M. Pardede

    2008-03-01

    Full Text Available We carried out a cross sectional study to analyze hemodynamic parameters of single-chamber ventricular pacemaker compared with dual-chamber pacemaker by using thoracic electrical bioimpedance monitoring method (Physio Flow™ - a novel simple non-invasive measurement. A total of 48 consecutive outpatients comprised of 27 single chamber pacemaker and 21 dual chamber were analyzed. We measured cardiac parameters: heart rate, stroke volume index, cardiac output index, estimated ejection fraction, end diastolic volume, early diastolic function ratio, thoracic fluid index, and systemic parameters: left cardiac work index and systemic vascular resistance index. Baseline characteristic and pacemaker indication were similar in both groups. Cardiac parameters assessment revealed no significant difference between single-chamber pacemaker and dual-chamber pacemaker in heart rate, stroke volume index, cardiac index, estimated ejection fraction, end-diastolic volume, thoracic fluid index. There was significantly higher early diastolic function ratio in single-chamber pacemaker compared to dual-chamber pacemaker: 92% (10.2-187.7% vs. 100.6% (48.7-403.2%; p=0.006. Systemic parameters assessment revealed significantly higher left cardiac work index in single-chamber group than dual-chamber group 4.9 kg.m/m² (2.8-7.6 kg.m/m² vs. 4.3 kg.m/m² (2.9-7.2 kg.m/m²; p=0.004. There was no significant difference on systemic vascular resistance in single-chamber compared to dual-chamber pacemaker. Single-chamber ventricular pacemaker provides similar stroke volume, cardiac output and left cardiac work, compared to dual-chamber pacemaker. A non-invasive hemodynamic measurement using thoracic electrical bioimpedance is feasible for permanent pacemaker outpatients. (Med J Indones 2008; 17: 25-32Keywords: Permanent pacemaker, single chamber, dual chamber, thoracic electrical bioimpedance, hemodynamic parameter

  13. The origin of the cloud chamber;Les mysteres de la chambre a brouillard

    Energy Technology Data Exchange (ETDEWEB)

    Fadel, K. [Palais de la Decouverte, Dept. de Physique, 75 - Paris (France)

    2009-09-15

    This article draws the story of the Wilson chamber. In the second half of the 19. century, a general trend among scientists in Great-Britain was still the observation and the imitation of nature, this romantic approach was launched by Goethe 50 years before. In 1895, Wilson as a young physicist tried to reproduce fog in laboratory. His challenge was to reduce the role of dust particles in the Aitken method: the expansion of wet-saturated air loaded with dust particles creates fog. In 1896, at the Cavendish laboratory, he discovered that ions could be very efficient 'dust particles' to condensate vapor and in 1898 he wrote that the expansion method is probably one of the most sensitive method to detect radiation emitted by radioactive materials. The Wilson chamber got a full success only from the twenties and was intensively used for 30 years in particles and nuclear physics laboratories. This detector allowed the experimental discovery of the positron, the muon and strange particles. (A.C.)

  14. Simplifying Bridge Expansion Joint Design and Maintenance

    Science.gov (United States)

    2011-10-19

    This report presents a study focused on identifying the most durable expansion joints for the South : Carolina Department of Transportation. This is performed by proposing a degradation model for the : expansion joints and updating it based on bridge...

  15. Advanced Modified High Performance Synthetic Jet Actuator with Curved Chamber

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Su, Ji (Inventor); Jiang, Xiaoning (Inventor)

    2014-01-01

    The advanced modified high performance synthetic jet actuator with optimized curvature shape chamber (ASJA-M) is a synthetic jet actuator (SJA) with a lower volume reservoir or chamber. A curved chamber is used, instead of the conventional cylinder chamber, to reduce the dead volume of the jet chamber and increase the efficiency of the synthetic jet actuator. The shape of the curvature corresponds to the maximum displacement (deformation) profile of the electroactive diaphragm. The jet velocity and mass flow rate for the ASJA-M will be several times higher than conventional piezoelectric actuators.

  16. String quartet chamber music : the personal way of music development

    OpenAIRE

    Montant, Laure

    2012-01-01

    The subject of this thesis is about chamber music and more specifically string quartet. How and why chamber music should be a real part of a musician’s life. In the introduction, it is explained why it is important to play chamber music and what qualities a musician needs to be good at it. Then a description of what is chamber music litterally is exposed. The history recounts what was chamber music from its early beginings until our days and why it has so much evolves. About interpretation, t...

  17. An experimental propane bubble chamber; Sur une chambre a bulles experimentale a propane

    Energy Technology Data Exchange (ETDEWEB)

    Rogozinski, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    Describes a propane bubble chamber 10 cm in diameter and 5 cm deep. The body of the chamber is in stainless steel, and it has two windows of polished hardened glass. The compression and decompression of the propane are performed either through a piston in direct contact with the liquid, or by the action on the liquid, through a triple-mylar-Perbunan membrane, of a compressed gas. The general and also optimum working conditions of the chamber are described, and a few results are given concerning, in particular, the tests of the breakage-resistance of the windows and the measurements of the thermal expansion of the compressibility isotherm for the propane employed. (author) [French] Description d'une chambre a bulles a propane de 10 cm de diametre et de 5 cm de profondeur. La chambre, dont le corps est en acier inoxydable, est munie de deux fenetres en verre poli et trempe. La compression et la detente du propane sont effectuees, soit a l'aide d'un piston en contact direct avec le liquide, soit en faisant agir sur ce dernier un gaz comprime a travers une triple membrane de teflon-mylar-perbunan. On decrit les conditions generales, ainsi que les conditions optimales de fonctionnement de la chambre et l'on signale un certain nombre de resultats obtenus concernant, notamment, les essais de resistance a la rupture des fenetres et les mesures de dilatation thermique de compressibilite isotherme du propane utilise. (auteur)

  18. Numerical simulation of performance of heavy ion inertial confinement fusion target with ellipsoidal chamber

    Energy Technology Data Exchange (ETDEWEB)

    Basin, A.A. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Vatulin, V.V. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Vakhlamova, L.L. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Vinokurov, P.A. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Dement`ev, Yu.A. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Eliseev, G.M. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Ermolovich, V.F. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Morenko, L.Z. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Morenko, A.I. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Remizov, G.N. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Romanov, Yu.A. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Ryabikina, N.A. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Skrypnik, S.I. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Skidan, G.I. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Tikhomirov, B.P. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.; Shagaliev, R.M. [Russian Federal Nucl. Centre, Arzamas (Russian Federation). Inst. of Exp. Phys.

    1996-11-01

    To solve the design problem of an inertial thermonuclear fusion facility requires the united efforts of scientists in various countries. In the field of heavy ion fusion a collaboration between scientists in Germany and Russia is under successful development. VNIIEF possesses advanced software for numerical simulation of the processes in thermonuclear target operation. This paper describes a target design suggested and being studied by scientists of Frankfurt University and GSI which is based on 2D non-stationary calculation of the X-ray energy transport and capsule compression. The target consists of a spherical capsule with DT fuel and an ellipsoidal chamber containment. The ion beam energy is released in two fixed converters located on the chamber axis symmetricall with respect to the capsule. The X-ray field is formed on the capsule surface with a set of special shields. The basic aim of our research is to estimate the effect of gas dynamic expansion of the chamber walls, shields and capsule on the target operation. To increase the reliability of the obtained results and the assessment of probable errors in predicting radiation field parameters and the capsule state, the calculations were accomplished in a kinetic arrangement with various techniques. (orig.)

  19. Cost advantage of dual-chamber versus single-chamber cardioverter-defibrillator implantation.

    Science.gov (United States)

    Goldberger, Zachary; Elbel, Brian; McPherson, Craig A; Paltiel, A David; Lampert, Rachel

    2005-09-06

    The purpose of this study was to determine the least expensive strategy for device selection in patients receiving implantable cardioverter-defibrillators (ICDs). Device cost for a single-chamber ICD is less than an atrioventricular (dual-chamber) ICD (AV-ICD); however, some patients without clinical need for AV-ICD at implantation might require a later upgrade, potentially offsetting the initial cost advantage of the single-chamber device. Decision analysis was used to estimate expected resource utilization costs of three alternative implantation strategies: 1) single-chamber device in all, with later upgrade to AV-ICD if needed; 2) initial implantation of an AV-ICD in all; and 3) targeted device selection on the basis of results of electrophysiologic testing (presence or absence of induced bradyarrhythmias or atrial arrhythmias). Clinical base estimates were obtained from retrospective review of all patients receiving ICDs between June 1997 and July 2001 at a single university hospital. Economic inputs were collected from national and single-center sources. In patients without other indications for electrophysiologic study (EPS), the expected per-person cost was least with the strategy of universal initial AV-ICD implantation (36,232 dollars) compared with initial single-chamber ICD/upgrade as needed (39,230 dollars) or EPS-guided selection (41,130 dollars). Sensitivity analyses demonstrated that universal AV-ICD implantation remained least expensive with upgrade rates as low as 10%. At a 5% upgrade rate, AV-ICD remained cheapest if the device cost-differential narrowed to 1,568 dollars. For patients undergoing EPS for risk assessment, EP-guided selection was least expensive. The strategy of universal AV-ICD implantation, which provides the benefits of dual-chamber capability while obviating any potential need for future upgrade, is the least costly strategy for most patient populations receiving ICDs.

  20. Dynamic consideration of smog chamber experiments

    Directory of Open Access Journals (Sweden)

    W. K. Chuang

    2017-08-01

    Full Text Available Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU. We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  1. Liquid rocket combustion chamber acoustic characterization

    Directory of Open Access Journals (Sweden)

    Cândido Magno de Souza

    2010-09-01

    Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities.

  2. Dynamic consideration of smog chamber experiments

    Science.gov (United States)

    Chuang, Wayne K.; Donahue, Neil M.

    2017-08-01

    Recent studies of the α-pinene + ozone reaction that address particle nucleation show relatively high molar yields of highly oxidized multifunctional organic molecules with very low saturation concentrations that can form and grow new particles on their own. However, numerous smog-chamber experiments addressing secondary organic aerosol (SOA) mass yields, interpreted via equilibrium partitioning theory, suggest that the vast majority of SOA from α-pinene is semivolatile. We explore this paradox by employing a dynamic volatility basis set (VBS) model that reproduces the new-particle growth rates observed in the CLOUD experiment at CERN and then modeling SOA mass yield experiments conducted at Carnegie Mellon University (CMU). We find that the base-case simulations do overpredict observed SOA mass but by much less than an equilibrium analysis would suggest; this is because delayed condensation of vapors suppresses the apparent mass yields early in the chamber experiments. We further find that a second VBS model featuring substantial oligomerization of semivolatile monomers can match the CLOUD growth rates with substantially lower SOA mass yields; this is because the lighter monomers have a higher velocity and thus a higher condensation rate for a given mass concentration. The oligomerization simulations are a closer match to the CMU experiments than the base-case simulations, though they overpredict the observations somewhat. However, we also find that if the chemical conditions in CLOUD and the CMU chamber were identical, substantial nucleation would have occurred in the CMU experiments when in fact none occurred. This suggests that the chemical mechanisms differed in the two experiments, perhaps because the high oxidation rates in the SOA formation experiments led to rapid termination of peroxy radical chemistry.

  3. The Evolution and Development of Cephalopod Chambers and Their Shape.

    Science.gov (United States)

    Lemanis, Robert; Korn, Dieter; Zachow, Stefan; Rybacki, Erik; Hoffmann, René

    2016-01-01

    The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth.

  4. Anterior chamber intra ocular lens implantation.

    OpenAIRE

    Raju N

    1989-01-01

    The role of A.C. IOL in modern implant surgery has become somewhat debatable, since, the choice procedure to day is undoubtedly an ECCE with a PC lens implant preferably in the capsular bag. Even so, anterior chamber lens implantation has its definite indications. As such it is necessary for the implant surgeon to be familiar with the latest technique in this modality of surgery as well. Many of the complications of earlier rigid model AC IOLs were mainly due to defective lens design. With th...

  5. Posterior chamber intraocular lens dislocations and malpositions.

    Science.gov (United States)

    Obstbaum, S A; To, K

    1989-08-01

    Decentration and malposition of posterior chamber intraocular lenses (PC IOL) accounts for one of the remaining and unresolved conditions associated with the implantation of these lenses. This condition assumes importance since in approximately 50% of cases where a PC IOL is removed there is an aspect of improper positioning. The common types of malpositions are: pupil capture; sunset syndrome; sunrise syndrome; horizontal decentration; and the windshield wiper syndrome. This paper will explore the causes and management of these conditions and discuss the virtues of capsular bag implantation.

  6. Chamber service module (CSM1) for MDT

    CERN Document Server

    Binchi, P

    2002-01-01

    CSM-1 is the second and latest version of the high speed electronic unit whose primary task is to multiplex serial data from up to 18 ASD /TDC cards located at the ends of the Monitored Drift Tubes. Each CSM will capture data from all 24 channel TDC (AMT-2 units) of a given chamber and transfer it along a single optic fiber to the MROD, the event builder and readout driver. The core of the board is a Xilinx VirtexII FPGA which will use JTAG protocol (IEEE Std. 1149.1) for logic configuration parameter loading.

  7. Vacuum chamber for containing particle beams

    Science.gov (United States)

    Harvey, A.

    1985-11-26

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

  8. Microstrip gas chambers on implanted substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pallares, A. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Barthe, S. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France); Bergtold, A.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Brom, J.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Cailleret, J. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Christophel, E. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Coffin, J. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Eberle, H. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Fang, R. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Fontaine, J.C. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Geist, W. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Kachelhoffer, T. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Levy, J.M. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Mack, V. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Schunck, J.P. [Laboratoire PHASE (UPR 292 du CNRS), 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2 (France); Sigward, M.H. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires

    1995-12-11

    We have studied the performance of several Microstrip Gas Chamber (MSGC) prototypes made on standard Desag D263 boron implanted glass. The purpose of the implantation is to reduce the surface resistance. The long term stability of this implantation has been measured under applied bias voltage. Comparative tests have been carried out on prototypes made on implanted and unimplanted detectors under electron ({sup 90}Sr) and X-ray (8 keV) irradiation. The total dose was approximately 7 mC/cm. (orig.).

  9. Liquid ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    Physik. 42, 303-344,        1913. [3]    KRAMERS, H.A.: On a modification of Jaffe's theory pf column-ionization. Physica. 10, 18,        665-675, 1952. [4]    CHU, J.C.H., GRANT, WH., ALMOND, P.R.: A liquid Ionization Chamber for neutron        dosimetry. Phys. Med. Biol. 6, 25, 1133-1148, 1980....

  10. Investigation on temperature separation and flow behaviour in vortex chamber

    Science.gov (United States)

    Matsuno, Yuhi; Fukushima, Yusuke; Matsuo, Shigeru; Hashimoto, Tokitada; Setoguchi, Toshiaki; Kim, Heuy Dong

    2015-04-01

    In the previous researches, it is known that the swirl flow in circular pipe causes the temperature separation. Recently, it is shown that the temperature separation occurs in a vortex chamber when compressed air are pumped into this device from the periphery. Especially, in a cavity installed in the periphery of the chamber, the highest temperature was observed. Therefore, it is expected that this device can be used as a heat source in the engineering field. In recent researches, the mechanism of temperature separation in vortex chamber has been investigated by some researchers. However, there are few researches for the effect of diameter and volume of vortex chamber, height of central rod and position of cavity on the temperature separation. Further, no detailed physical explanation has been made for the temperature separation phenomena in the vortex chamber. In the present study, the effects of chamber configuration and position of the cavity on temperature separation in the vortex chamber were investigated experimentally.

  11. Golden Jubilee photos: The first CERN bubble chamber

    CERN Multimedia

    2004-01-01

    In the 1950s and 1960s, bubble and spark chambers were the dominant experimental tools in high-energy physics. While spark chambers were usually built and fitted to specific experiments, bubble chambers were constructed as general purpose devices that could be used for a variety of experiments. At CERN, the bubble chamber programme started under Charles Peyrou in the late 1950s. The first of CERN's bubble chambers, a 30 cm hydrogen chamber, is seen here being inserted into its vacuum tank. The HBC30, as it was called, took its first beam from the SC in 1959. One of the first pictures taken, of a positive pion-proton interaction, began a long series of pretty images for which bubble chambers would become famous. When it stopped operating in spring 1962, the HBC30 had consumed 150 km of film in its 3 years of operation.

  12. 48 CFR 570.403 - Expansion requests.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Expansion requests. 570.403 Section 570.403 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION SPECIAL... Continued Space Requirements 570.403 Expansion requests. (a) If the expansion space is in the general scope...

  13. Expansion of protein domain repeats.

    Directory of Open Access Journals (Sweden)

    Asa K Björklund

    2006-08-01

    Full Text Available Many proteins, especially in eukaryotes, contain tandem repeats of several domains from the same family. These repeats have a variety of binding properties and are involved in protein-protein interactions as well as binding to other ligands such as DNA and RNA. The rapid expansion of protein domain repeats is assumed to have evolved through internal tandem duplications. However, the exact mechanisms behind these tandem duplications are not well-understood. Here, we have studied the evolution, function, protein structure, gene structure, and phylogenetic distribution of domain repeats. For this purpose we have assigned Pfam-A domain families to 24 proteomes with more sensitive domain assignments in the repeat regions. These assignments confirmed previous findings that eukaryotes, and in particular vertebrates, contain a much higher fraction of proteins with repeats compared with prokaryotes. The internal sequence similarity in each protein revealed that the domain repeats are often expanded through duplications of several domains at a time, while the duplication of one domain is less common. Many of the repeats appear to have been duplicated in the middle of the repeat region. This is in strong contrast to the evolution of other proteins that mainly works through additions of single domains at either terminus. Further, we found that some domain families show distinct duplication patterns, e.g., nebulin domains have mainly been expanded with a unit of seven domains at a time, while duplications of other domain families involve varying numbers of domains. Finally, no common mechanism for the expansion of all repeats could be detected. We found that the duplication patterns show no dependence on the size of the domains. Further, repeat expansion in some families can possibly be explained by shuffling of exons. However, exon shuffling could not have created all repeats.

  14. Operation of high rate microstrip gas chambers

    CERN Document Server

    Barr, A J; Bouclier, Roger; Capéans-Garrido, M; Dominik, Wojciech; Manzin, G; Million, Gilbert; Hoch, M; Ropelewski, Leszek; Sauli, Fabio; Sharma, A

    1996-01-01

    We describe recent measurements carried out in well controlled and reproducible conditions to help understanding the factors affecting the short and long term behaviour of Microstrip Gas Chambers. Special care has been taken concerning the gas purity and choice of materials used in the system and for the detectors construction. Detectors built on glasses with surface resistivity in the range $10^{13}-10^{15} \\Omega/\\Box$ have shown satisfactory performance as they do not show charging-up process at high rate and stand the large doses required for the future high luminosity experiments (~10 mC·cm-1·yr-1). Concerning the lifetime measurements, it has been observed that chambers manufactured on high-resistivity glass are far more susceptible of suffering ageing than detectors made on low resistivity, electron-conducting supports, independently of the metal used for the artwork (chromium or gold) at least in clean gas conditions. The successfully operation in the laboratory of detectors manufactured on diamond-...

  15. Translimbal fixation of posterior chamber lenses.

    Science.gov (United States)

    Yospaiboon, Yosanan; Wongwai, Pantipa; Ratanapakorn, Tanapat; Sinawat, Suthasinee

    2005-11-01

    To evaluate the result of a surgical technique to insert and secure a standard posterior chamber lens through a simple limbal incision in eyes that had no capsular support or whose capsule was inadvertently ruptured during extracapsular cataract extraction. Retrospective review of the medical records of patients who underwent translimbal fixation of posterior chamber lenses according to age, gender, preoperative visual acuity, postoperative visual acuity, follow-up period and any complications, especially those that may be related to the surgical technique. Twelve patients were recruited in the present study. The patents' age ranged from 31 to 77 years, with a mean of 62.58 years. There were 9 male and 3 female patients. The preoperative visual acuity ranged from hand motion to counting fingers, and the postoperative visual acuity ranged from 6/6 to 6/24 except one patient who had postoperative visual acuity of counting fingers due to a pre-existing macular hole. The length of follow-up period ranged from 3 to 12 months, with a mean of 6.17 months. There was no clinically significant lens-related complication. This simple surgical technique controls the location of the needle entry and exit to decrease the risk of bleeding and increase the chance of ciliary sulcus placement. An inferior groove was made to bury the suture knot and was sutured closed to prevent the knot erosion through the conjunctiva.

  16. Suppressing drift chamber diffusion without magnetic field

    CERN Document Server

    Martoff, C J; Ohnuki, T; Spooner, N J C; Lehner, M

    2000-01-01

    The spatial resolution in drift chamber detectors for ionizing radiation is limited by diffusion of the primary electrons. A strong magnetic field along the drift direction is often applied (Fancher et al., Nucl. Instr. and Meth. A 161 (1979) 383) because it suppresses the transverse diffusion, improving the resolution but at considerable increase in cost and complexity. Here we show that transverse track diffusion can be strongly suppressed without any magnetic field. This is achieved by using a gas additive which reversibly captures primary ionization electrons, forming negative ions. The ions drift with thermal energies even at very high drift fields and low pressures (E/P=28.5 V/cm torr), and the diffusion decreases with increasing drift field. Upon arrival at the avalanche region of the chamber the negative ions are efficiently stripped and ordinary avalanche gain is obtained. Using this technique, r.m.s. transverse diffusion less than 200 mu m has been achieved over a 15 cm drift path at 40 torr with ze...

  17. Prototype for the ALEPH Time Projection Chamber

    CERN Multimedia

    1980-01-01

    This is a prototype endplate piece constructed during R&D for the ALEPH Time Projection Chamber (TPC). ALEPH was one of 4 experiments at CERN's 27km Large Electron Positron collider (LEP) that ran from 1989 to 2000. ALEPH's TPC was a large-volume tracking chamber, 4.4 metres long and 3.6 metres in diameter - the largest TPC in existance at the time. This object is one of the endplates of a “Kind” sector, the smallest of the three types of sectors. The patterns etched into the copper form the cathode pads that measured particle track coordinates in the r-phi direction. It included a laser calibration system, a gating system to prevent space charge buildup, and a new radial pad geometry to improve resolution. the ALEPH TPC allowed for precise momentum measurements of the high-momentum particles from W and Z decays. The following institutes participated: CERN, Athens, Glasgow, Mainz, MPI Munich, INFN-Pisa, INFN-Trieste, Wisconsin.

  18. Aging Investigation of CMS EMU Prototype Chambers

    CERN Document Server

    Ferguson*, T; Krivshich, Anatoli; Kuznetsova, Ekaterina; Lobachev, Evgeny; Mitselmakher, Guenakh; Schipunov, L

    1999-01-01

    The aging investigation results of CMS EMU prototype chambers are presented. Aging tests under sustained irradiation by a 90Sr 2 Ci were performed with three working gas mixtures Ar( 30%)+CO2( 50%)+CF4( 20%), Ar( 30%)+CO2( 70%) and Ar( 40%)+CO2( 50%)+CF4( 10%). For Ar( 30%)+CO2( 50%)+CF4( 20%) mixture gas gain reduction was not observed up to the accumulated charge Q = 13.56 C/cm. However, the dark current in the chamber was noticeable starting already from Q = 2 C/cm. The absence of the CF4 ( in the Ar/CO2 gas mixture) caused fast aging deterioration, and Q = 0.2 C/cm was enough to obtain 50% of the gas gain reduction. In the test with Ar( 40%)+CO2( 50%)+CF4( 10%) mixture the gas gain reduction and the dark current increase were not observed up to Q = 13.35 C/cm. Reduction of the gas flow rate to 0.1 volume per day caused 50% of the gain decrease due to the gas pollution by fragments of dissociated gas molecules. The gain restored after switching back to the 1 volume per day flow rate. Studies with electroni...

  19. COLDDIAG: A Cold Vacuum Chamber for Diagnostics

    CERN Document Server

    Casalbuoni, S; Gerstl, S; Grau, A W; Hagelstein, M; Saez de Jauregui, D; Boffo, C; Sikler, G; Baglin, V; Cox, M P; Schouten, J C; Cimino, R; Commisso, M; Spataro, B; Mostacci, A; Wallen, E J; Weigel, R; Clarke, J; Scott, D; Bradshaw, T; Jones, R; Shinton, I

    2011-01-01

    One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron energy and flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source Diamond is foreseen in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.

  20. Contribution of thermal expansion and

    Directory of Open Access Journals (Sweden)

    O.I.Pursky

    2007-01-01

    Full Text Available A theoretical model is developed to describe the experimental results obtained for the isobaric thermal conductivity of rare gas solids (RGS. The isobaric thermal conductivity of RGS has been analysed within Debye approximation with regard to the effect of thermal expansion. The suggested model takes into consideration the fact that thermal conductivity is determined by U-processes while above the phonon mobility edge it is determined by "diffusive" modes migrating randomly from site to site. The mobility edge ω0 is determined from the condition that the phonon mean-free path restricted by the U-processes cannot be smaller than half of the phonon wavelength.

  1. Gravitational entropy of cosmic expansion

    CERN Document Server

    Sussman, Roberto A

    2014-01-01

    We apply a recent proposal to define "gravitational entropy" to the expansion of cosmic voids within the framework of non-perturbative General Relativity. By considering CDM void configurations compatible with basic observational constraints, we show that this entropy grows from post-inflationary conditions towards a final asymptotic value in a late time fully non-linear regime described by the Lemaitre-Tolman-Bondi (LTB) dust models. A qualitatively analogous behavior occurs if we assume a positive cosmological constant consistent with a $\\Lambda$-CDM background model. However, the $\\Lambda$ term introduces a significant suppression of entropy growth with the terminal equilibrium value reached at a much faster rate.

  2. Cerrejon expansion in a tight market?

    Energy Technology Data Exchange (ETDEWEB)

    Pretelt, A. [Carbocol SA, Bogota (Colombia)

    1995-12-31

    Examines plans to expand Carbocol`s Cerrejon North Zone coal mine (Colombia). Covers: background; current status of the project; main features of the expansion (i.e. coal reserves, infrastructure, operating costs, expansion schedule and market factors); advantages of expansion; and Carbocol`s vision of the market. A positive decision to expand will depend on the results of a feasibility class III study which will define in exact terms the technical and economic aspects of the expansion and the best way to execute it. The study will be completed next year. The expansion programme should improve the profitability of the project. 10 figs.

  3. Imagination as expansion of experience.

    Science.gov (United States)

    Zittoun, Tania; Cerchia, Frédéric

    2013-09-01

    This paper proposes a developmental view on imagination: from this perspective, imagination can be seen as triggered by some disrupting event, which generates a disjunction from the person's unfolding experience of the "real" world, and as unfolding as a loop, which eventually comes back to the actual experience. Examining recent and classical theorization of imagination in psychology, the paper opposes a deficitary view of imagination to an expansive notion of imagination. The paper explores Piaget, Vygotsky, Harris and Pelaprat & Cole consider: 1) What does provoke a "rupture" or disjunction? 2) What are the psychological processes involved in the imaginary loop? 3) What nourishes such processes? 4) What are the consequences of such imaginary loop, or what does it enable doing? The paper proposes to adopt an expansive view of imagination, as Vygotsky proposed-a perspective that has been under-explored empirically since his seminal work. To stimulate such sociocultural psychology of imagination, two empirical examples are provided, one showing how children make sense of metaphor in an experimental setting, the other showing a young person using a novel met at school as symbolic resource.

  4. Fast algorithms for Quadrature by Expansion I: Globally valid expansions

    Science.gov (United States)

    Rachh, Manas; Klöckner, Andreas; O'Neil, Michael

    2017-09-01

    The use of integral equation methods for the efficient numerical solution of PDE boundary value problems requires two main tools: quadrature rules for the evaluation of layer potential integral operators with singular kernels, and fast algorithms for solving the resulting dense linear systems. Classically, these tools were developed separately. In this work, we present a unified numerical scheme based on coupling Quadrature by Expansion, a recent quadrature method, to a customized Fast Multipole Method (FMM) for the Helmholtz equation in two dimensions. The method allows the evaluation of layer potentials in linear-time complexity, anywhere in space, with a uniform, user-chosen level of accuracy as a black-box computational method. Providing this capability requires geometric and algorithmic considerations beyond the needs of standard FMMs as well as careful consideration of the accuracy of multipole translations. We illustrate the speed and accuracy of our method with various numerical examples.

  5. Investigation of mixing chamber for experimental FGD reactor

    Directory of Open Access Journals (Sweden)

    Novosád Jan

    2017-01-01

    Full Text Available This article deals with numerical investigation of flow and mixing of air and sulphur dioxide SO2 in designated mixing chamber. The mixing chamber is a part of experimental laboratory reactor designed for simulating the flue gas desulfurization (FGD process. Aim of this work is the numerical investigation of effect of different mixing chamber geometries to mixture composition, especially to mass fraction of sulphur dioxide. Using of similar concentration of sulphur dioxide in the experimental reactor as in the real process is necessary to be able to make additional research. Conclusion describes the effect of different geometries of mixing chamber to mixing. The aim of this work is to develop perfectly works mixing chamber, which will be manufactured and then implemented into experimental FGD reactor. The results will be validated by experiment after the mixing chamber will be manufactured.

  6. Characterization of a homemade ionization chamber for radiotherapy beams

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Lucio P., E-mail: lpneves@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Perini, Ana P., E-mail: aperini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Santos, Gelson P. dos, E-mail: gpsantos@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Xavier, Marcos, E-mail: mxavier@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.br [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, 50740-540 Recife (Brazil); Caldas, Linda V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000 Sao Paulo (Brazil)

    2012-07-15

    A homemade cylindrical ionization chamber was studied for routine use in therapy beams of {sup 60}Co and X-rays. Several characterization tests were performed: leakage current, saturation, ion collection efficiency, polarity effect, stability, stabilization time, chamber orientation and energy dependence. All results obtained were within international recommendations. Therefore the homemade ionization chamber presents usefulness for routine dosimetric procedures in radiotherapy beams. - Highlights: Black-Right-Pointing-Pointer A homemade ionization chamber was studied for routine use in radiotherapy. Black-Right-Pointing-Pointer Several characterization tests were performed and the results were satisfactory. Black-Right-Pointing-Pointer This chamber was compared to commercial ones and the results were similar. Black-Right-Pointing-Pointer This chamber is suitable for calibration procedures in {sup 60}Co beams.

  7. Emulsion chamber observations and interpretation (HE 3)

    Science.gov (United States)

    Shibata, M.

    1986-01-01

    Experimental results from Emulsion Chamber (EC) experiments at mountain altitudes or at higher levels using flying carriers are examined. The physical interest in this field is concentrated on the strong interaction at the very high energy region exceeding the accelerator energy, also on the primary cosmic ray intensity and its chemical composition. Those experiments which observed cosmic ray secondaries gave information on high energy interaction characteristics through the analyses of secondary spectra, gamma-hadron families and C-jets (direct observation of the particle production occuring at the carbon target). Problems of scaling violation in fragmentation region, interaction cross section, transverse momentum of produced secondaries, and some peculiar features of exotic events are discussed.

  8. RETAINED STONE PIECE IN ANTERIOR CHAMBER

    Directory of Open Access Journals (Sweden)

    ZvornicaninJasmin, Nadarevic-VodencarevicAmra

    2015-04-01

    Full Text Available ABSTRACT We read with interest the article by Surekha et al. regarding the retained stone piece in anterior chamber. Similar to the results of previous studies, the authors found that delayed intraocular foreign body (IOFB management can result in good visual outcome without an apparent increased risk of endophthalmitis or other deleterious side effects. However, the authors failed to explain the exact reason for the diminution of vision in patients left eye. It is unclear what the uncorrected visual acuity was and what kind of correction was used, more precisely type and amount of cylinder, given the presence of the corneal opacity. Since the size of the IOFB is approximately 4x4x1mm, significant irido-corneal angle changes resulting in intraocular pressure raise and optic nerve head damage can be expected. Traumatic glaucoma following open globe injury can occur in 2.7 to 19% of cases, with several risk factors associated with glaucoma development (advanced age, poor visual acuity at presentation,perforating rather than penetrating ocular injury,lens injury, presence of vitreous hemorrhage and presence of an IOFB. Earlier reportsof latetraumaticoptic neuropathy onset, even after several years, indicate that this possibility cannot be completely ruled out too. Therefore, repeated intraocular pressure measurements, gonioscopy, pupillary reaction assessment, together with through posterior segment examination including visual field and optical coherence tomography examinations can be useful in determining the possible optic nerve damage as one of the possible reasons for visual acuity reduction. The authors did not suggest any operative treatment at this time. However, it should bear in mind that the inert anterior chamber IOFB could be a risk factor for non-infectious endophthalmitis development even after many years. Also, long term retained anterior chamber foreign body leads to permanent endothelial cell loss and can even result in a corneal

  9. Neutron sensitivity of thin gap chambers

    CERN Document Server

    Nanjo, H; Hasuko, K; Ishino, M; Kobayashi, T; Takemoto, T; Tsuno, S; Ye, B

    2005-01-01

    Thin gap chambers (TGC) will be used for triggering forward muons in the ATLAS detector for the LHC at CERN. A large amount of neutron background is foreseen in the ATLAS experiment. This paper describes the measurements of the neutron sensitivities (detection efficiencies) of the TGCs. The sensitivities of both small and real size TGCs to 2.5 and 14MeV mono-energetic neutrons were measured. For a small size TGC, sensitivities of 0.032% and 0.10% were measured to 2.5 and 14MeV neutrons, respectively, whereas for a real size TGC, sensitivities of 0.048% and 0.13% were measured. These measured values were in reasonably good agreement with the simulations based on the Geant4.

  10. Foreign Body Embedded in Anterior Chamber Angle

    Directory of Open Access Journals (Sweden)

    Shmuel Graffi

    2012-01-01

    Full Text Available Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by an external approach without utilizing a magnet. The patient's final outcome was favorable. Discussion. The above is a rare clinical situation, which is impossible to detect on slit-lamp examination without a gonioscopic view. Proper imaging and a specific management are mandatory in order to achieve favorable outcome.

  11. The time projection chamber at triumf

    Science.gov (United States)

    Bryman, D.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P.; Dixit, M. S.; Hargrove, C. K.; Mes, H.; Bennett, A.; Macdonald, J. A.; Skegg, R.; Spuller, J.; Burnham, A.; Hasinoff, M.; Poutissou, J.-M.; Azuelos, G.; Depommier, P.; Martin, J.-P.; Poutissou, R.; Blecher, M.; Gotow, K.; Carter, A. L.

    1984-02-01

    The time projection chamber at TRIUMF is being used to search for muon-electron conversion. The best spatial resolution in the TPC, σ≂200 μm, occurs at the minimum drift length and for an optimum track-to-anode crossing angle determined by the magnetic field. The observed resolution is dependent on th diffusion of the drifting electrons, the track-to-anode crossing angle, E↘×B↘ effects near the anode wire and the discrete nature of the ionization process. Distortions due to positive ions leaking back into the drift volume from the anode wire region have been nearly eliminated by the use of a pulsed dual grid system.

  12. Acoustic analysis of a semi-anechoic chamber with intersection

    OpenAIRE

    P. Nassiri; M. R. Monazzam; F. Zivary Delavar

    2014-01-01

    Introduction: The previous studies have used fibrous absorbents usually in the form of cone-shaped wedges for making anechoic and semi-anechoic chambers which their design and construction have been costly and difficult. The present study aimed to design a semi-anechoic chamber, using rectangular fibrous absorbents and also perform acoustic analysis for it. . Material and Method: In the present study, which was done at semi-anechoic chamber of the laboratory in Tehran University of Medical...

  13. Ageing tests for the MEG II drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, M., E-mail: marco.venturini@pi.infn.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Baldini, A.M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Baracchini, E. [ICEPP, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Cei, F.; D' Onofrio, A. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dussoni, S.; Galli, L.; Grassi, M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Nicolò, D. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Signorelli, G.; Tenchini, F. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Zermini, A. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

    2016-07-11

    The MEG II drift chamber will track positrons from μ{sup +} decays in a very harsh environment. For testing the robustness of the chamber to ageing effects an irradiation facility was set up at INFN Pisa. - Highlights: • We built up an X-ray facility for ageing studies of particle detectors. • Stable irradiation conditions were obtained over one-month timescale. • A moderate gain loss is expected for the MEG II drift chamber.

  14. Central drift chamber for rare kaon decay spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Cresswell, J.; Numao, T.

    1985-10-01

    Design of the central drift chamber for BNL experiment 787 and measurement of the decay K/sup +/ ..-->.. ..pi../sup +/ nu anti nu are discussed. A jet chamber type cell with 6 sense wires and no interspersed field wires has been designed to achieve good spatial resolution and efficiency in a 1 T magnetic field. Results of the testing of a prototype chamber are presented.

  15. NASA Teams With Army in Vortex Combustion Chamber Engine Test

    Science.gov (United States)

    2003-01-01

    This photograph depicts one of over thirty tests conducted on the Vortex Combustion Chamber Engine at Marshall Space Flight Center's (MSFC) test stand 115, a joint effort between NASA's MSFC and the U.S. Army AMCOM of Redstone Arsenal. The engine tests were conducted to evaluate an irnovative, 'self-cooled', vortex combustion chamber, which relies on tangentially injected propellants from the chamber wall producing centrifugal forces that keep the relatively cold liquid propellants near the wall.

  16. Double anterior chamber in a patient with glaucoma and microspherophakia

    Directory of Open Access Journals (Sweden)

    Hamid Khakshoor

    2011-01-01

    Full Text Available We report the case of a 16-year-old woman with microspherophakia and secondary open angle glaucoma. The patient presented with a membrane dividing the anterior chamber into two segments without edema or Descemet′s membrane detachment. Slit lamp biomicroscopy, Pentacam, and specular microscopy images were obtained. Double anterior chamber is primarily found in patients with anterior chamber anomalies when there is no history of surgery or trauma.

  17. On the equisummability of Hermite and Fourier expansions

    Indian Academy of Sciences (India)

    We prove an equisummability result for the Fourier expansions and Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions.

  18. Relationship Development in Greenfield Expansions

    DEFF Research Database (Denmark)

    Drogendijk, Rian; Andersson, Ulf

    2013-01-01

    This paper investigates conceptually how new Greenfield subsidiaries develop relationships over time. We focus our analysis on the earliest start-up stage of new Greenfield subsidiaries, and on the dynamics of relationships development with five different groups of actors within the MNC...... and the local environment of the new Greenfield. We argue that relationship strength, or the intensity of interaction and resource exchange, depends on the new Greenfield''s degree of dependence or interdependence within these relationships and develop propositions based on institutional theory, resource...... dependency theory and network approaches. In the concluding sections we suggest directions for future work to enhance understanding of the dynamics of relationship management in new Greenfield expansions....

  19. Expansion of Physician Assistant Education.

    Science.gov (United States)

    Cawley, James F; Jones, P. Eugene; Miller, Anthony A; Orcutt, Venetia L

    2016-12-01

    Physician assistant (PA) educational programs were created in the 1960s to prepare a new type of health care practitioner. Physician assistant programs began as experiments in medical education, and later, they proved to be highly successful in preparing capable, flexible, and productive clinicians. The growth of PA educational programs in US medical education-stimulated by grants, public policy, and anticipated shortages of providers-has gone through 3 distinct phases. At present, such programs are in the midst of the third growth spurt that is expected to continue beyond 2020, as a large number of colleges and universities seek to sponsor PA programs and attain accreditation status. Characteristics of these new programs are described, and the implications of the current expansion of PA education are examined.

  20. Radiation Target Area Sample Environmental Chamber (RTASEC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. proposes the Radiation Target Area Sample Environmental Chamber (RTASEC) as an innovative approach enabling radiobiologists to investigate the...

  1. Repair of isolated double-chambered right ventricle.

    Science.gov (United States)

    El Kouache, M; Babakhoya, A; Labib, S; El Madi, A; Atmani, S; Harandou, M; Abouabdilah, Y; Hida, M

    2013-01-01

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal high-pressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity. We report the case of a 6-year-old infant who was admitted for growth retardation. The patient was diagnosed with an isolated DCRV without any other associated congenital anomalies. The patient underwent a successful cardiac surgical procedure of enlargement repair; he was discharged in good clinical condition with a normal cardiac function.

  2. Repair of isolated double-chambered right ventricle

    OpenAIRE

    M El Kouache; A Babakhoya; S Labib; A El Madi; S Atmani; M Harandou; Y Abouabdilah; M Hida

    2013-01-01

    The finding of a double-chambered right ventricle (DCRV) is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal high-pressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity. We report the case of a 6-year-old infant who was admitted for growth retardation. The patient was diagnosed with an isolated DCRV without any other associat...

  3. Propagation of the trip behavior in the VENUS vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ohama, Taro; Yamada, Yoshikazu

    1995-03-01

    The high voltage system of the VENUS vertex chamber occasionally trips by a discharge somewhere among cathode electrodes during data taking. This trip behavior induces often additional trips at other electrodes such as the skin and the grid electrodes in the vertex chamber. This propagation mechanism of trips is so complicated in this system related with multi-electrodes. Although the vertex chamber is already installed inside the VENUS detector and consequently the discharge is not able to observe directly, a trial to estimate the propagation has been done using only the information which appears around the trip circuits and the power supply of the vertex chamber. (author).

  4. Serial Tissue Expansion at the Same Site in Pediatric Patients: Is the Subsequent Expansion Faster?

    Directory of Open Access Journals (Sweden)

    Moon Ki Lee

    2017-11-01

    Full Text Available Background Serial tissue expansion is performed to remove giant congenital melanocytic nevi. However, there have been no studies comparing the expansion rate between the subsequent and preceding expansions. In this study, we analyzed the rate of expansion in accordance with the number of surgeries, expander location, expander size, and sex. Methods A retrospective analysis was performed in pediatric patients who underwent tissue expansion for giant congenital melanocytic nevi. We tested four factors that may influence the expansion rate: The number of surgeries, expander location, expander size, and sex. The rate of expansion was calculated by dividing the ‘inflation amount’ by the ‘expander size’. Results The expansion rate, compared with the first-time group, was 1.25 times higher in the second-or-more group (P=0.04 and 1.84 times higher in the third-or-more group (P<0.01. The expansion rate was higher at the trunk than at other sites (P<0.01. There was a tendency of lower expansion rate for larger expanders (P=0.03. Sex did not affect the expansion rate. Conclusions There was a positive correlation between the number of surgeries and the expansion rate, a positive correlation between the expander location and the expansion rate, and a negative correlation between the expander size and the expansion rate.

  5. Pressurized electrolysis stack with thermal expansion capability

    Science.gov (United States)

    Bourgeois, Richard Scott

    2015-07-14

    The present techniques provide systems and methods for mounting an electrolyzer stack in an outer shell so as to allow for differential thermal expansion of the electrolyzer stack and shell. Generally, an electrolyzer stack may be formed from a material with a high coefficient of thermal expansion, while the shell may be formed from a material having a lower coefficient of thermal expansion. The differences between the coefficients of thermal expansion may lead to damage to the electrolyzer stack as the shell may restrain the thermal expansion of the electrolyzer stack. To allow for the differences in thermal expansion, the electrolyzer stack may be mounted within the shell leaving a space between the electrolyzer stack and shell. The space between the electrolyzer stack and the shell may be filled with a non-conductive fluid to further equalize pressure inside and outside of the electrolyzer stack.

  6. Therapeutic effect of bilastine in Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber).

    Science.gov (United States)

    Hashiguchi, Kazuhiro; Wakabayashi, Ken-Ichiro; Togawa, Michinori; Saito, Akihiro; Okubo, Kimihiro

    2017-01-01

    Environmental exposure chambers have been used to expose subjects to aeroallergens to investigate the efficacy of prophylactic treatment with symptomatic agents in Japan. We first examined the therapeutic effect of bilastine (BIL), a novel non-sedative second-generation H 1 -antihistamine, in subjects with Japanese cedar pollinosis using an artificial exposure chamber (OHIO Chamber). This was a randomized, double-blind, four-way crossover, placebo- and active-controlled phase II study (trial registration number JapicCTI-132213). Subjects were exposed to cedar pollen (8000 grains/m 3 ) for 2 h on Day -1 and 4 h each on Day 1 and 2. BIL 10 or 20 mg, placebo, or fexofenadine hydrochloride (FEX) 60 mg was administered orally 1 h after the start of pollen exposure on Day 1. Placebo or FEX was administered 12 h after the first dosing. The primary efficacy endpoint was the sum of total nasal symptom score (TNSS) from 0 to 3 h after the Day 1 dosing. We enrolled 136 subjects and the sum of TNSS on Day 1 of the three active treatments was significantly lower than that of placebo and was maintained up to 26 h after the first dosing (Day 2). The sum of TNSS or sneezing score on Day 1 after BIL 20 mg was more significantly decreased than after FEX. Moreover, BIL showed a faster onset of action than FEX. We demonstrated the efficacy, rapid onset, and long duration of action of BIL in subjects with Japanese cedar pollinosis exposed to cedar pollen using the OHIO Chamber. Copyright © 2016 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  7. Fundamentals of Thermal Expansion and Thermal Contraction

    OpenAIRE

    Liu, Zi-Kui; Shang, Shun-Li; Wang, Yi

    2017-01-01

    Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and statistical mechanics. Its applications to cerium with colossal thermal expansion and Fe3Pt with th...

  8. Structure and thermal expansion of liquid bismuth

    Directory of Open Access Journals (Sweden)

    Mudry S.

    2015-12-01

    Full Text Available Experimental structural data for liquid Bi were used for estimation of the main structure parameters as well as the thermal expansion coefficient both in supercooled and superheated temperature ranges. It was shown that the equilibrium melt had a positive thermal expansion coefficient within a temperature range upon melting and a negative one at higher temperatures. The former was related to structure changes upon melting, whereas the latter with topologic disordering upon further heating. It was found that the superheated melt had a negative thermal expansion coefficient. The results obtained from structural data were compared with the thermal expansion coefficient calculated from the data of density for liquid Bi.

  9. Thermal expansion of L-ascorbic acid

    Science.gov (United States)

    Nicolaï, B.; Barrio, M.; Tamarit, J.-Ll.; Céolin, R.; Rietveld, I. B.

    2017-04-01

    The specific volume of vitamin C has been investigated by X-ray powder diffraction as a function of temperature from 110 K up to complete degradation around 440 K. Its thermal expansion is relatively small in comparison with other organic compounds with an expansivity α v of 1.2(3) × 10-4 K-1. The structure consists of strongly bound molecules in the ac plane through a dense network of hydrogen bonds. The thermal expansion is anisotropic. Along the b axis, the expansion has most leeway and is about 10 times larger than in the other directions.

  10. The Evolution and Development of Cephalopod Chambers and Their Shape.

    Directory of Open Access Journals (Sweden)

    Robert Lemanis

    Full Text Available The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth.

  11. Quantifying the "chamber effect" in CO2 flux measurements

    Science.gov (United States)

    Vihermaa, Leena; Childs, Amy; Long, Hazel; Waldron, Susan

    2014-05-01

    The significance of aquatic CO2 emissions has received attention in recent years. For example annual aquatic emissions in the Amazon basin have been estimated as 500 Mt of carbon1. Methods for determining the flux rates include eddy covariance flux tower measurements, flux estimates calculated from partial pressure of CO2 (pCO2) in water and the use floating flux chambers connected to an infra-red gas analyser. The flux chamber method is often used because it is portable, cheaper and allows smaller scale measurements. It is also a direct method and hence avoids problems related to the estimation of the gas transfer coefficient that is required when fluxes are calculated from pCO2. However, the use of a floating chamber may influence the flux measurements obtained. The chamber shields the water underneath from effects of wind which could lead to lower flux estimates. Wind increases the flux rate by i) causing waves which increase the surface area for efflux, and ii) removing CO2 build up above the water surface, hence maintaining a higher concentration gradient. Many floating chambers have an underwater extension of the chamber below the float to ensure better seal to water surface and to prevent any ingress of atmospheric air when waves rock the chamber. This extension may cause additional turbulence in flowing water and hence lead to overestimation of flux rates. Some groups have also used a small fan in the chamber headspace to ensure thorough mixing of air in the chamber. This may create turbulence inside the chamber which could increase the flux rate. Here we present results on the effects of different chamber designs on the detected flux rates. 1Richey et al. 2002. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416: 617-620.

  12. Expansion due to the anaerobic corrosion of iron

    Energy Technology Data Exchange (ETDEWEB)

    Smart, N.R.; Rance, A.P.; Fennell, P.A.H. [Serco Assurance, Culham Science Centre (United Kingdom)

    2006-12-15

    . Initially, three cells were set up: two contained alternate carbon steel and copper discs, and the third, a control cell, consisted of alternate stainless steel and copper discs. A slight contraction of the control cell was observed but no expansion was measured in the carbon steel-copper cells. Analytical measurements showed that the corrosion products were magnetite and hydrogen, indicating that anaerobic corrosion was occurring. In a second series of experiments, one experiment was carried out in which carbon steel was replaced with cast iron and in a further experiment air was allowed to enter the test chamber. No expansion was detected in either of these additional experiments. However, expansion was detected when a separate stack of copper and steel washers was corroded in ambient atmospheric conditions under very small compressive loads, and subjected to a wet-dry cycle, demonstrating that the experimental technique was capable of detecting corrosion-induced expansion if it were occurring. In parallel with the stress cell experiments, coupons of mild steel and cast iron were corroded in anoxic, artificial groundwater at 50 deg C and 80 deg C for several months. The coupons were examined using atomic force microscopy (AFM) to determine the mechanical properties and the structure of the corrosion product films, and X-ray photoelectron spectroscopy (XPS) to identify the chemical composition of the film. The report presents Young's modulus, thickness and hardness data for the oxides, which were much more compliant than the magnetite films formed at high temperatures, probably because of their high water content. The report considers the application of the results to assessing the performance of the SKB canister in a repository situation.

  13. Influence of chamber misalignment on cased telescoped (CT ammunition accuracy

    Directory of Open Access Journals (Sweden)

    D. Corriveau

    2016-04-01

    Full Text Available As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

  14. Collaborative Composing in High School String Chamber Music Ensembles

    Science.gov (United States)

    Hopkins, Michael T.

    2015-01-01

    The purpose of this study was to examine collaborative composing in high school string chamber music ensembles. Research questions included the following: (a) How do high school string instrumentalists in chamber music ensembles use verbal and musical forms of communication to collaboratively compose a piece of music? (b) How do selected variables…

  15. Development of Graphene Ion-Chamber for Radiation Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaegi; Ye, Sung-Joon [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    Graphene is an exciting material due to its high electrical and thermal conductivity. Recently, scientific research using graphene has been divided by two types of graphene. One is a pure graphene, and the other is graphene oxide (GO), which is chemically synthesized from graphite. A pure graphene is a single layer of graphite, and its physical characteristics are very exciting. However, making process and cost are quite complex and expensive to apply an industry. On the other hand, graphene oxide is easy to make and apply a real device. Until now, radiation dosimetry using an ion-chamber has been a standard protocol. For its high electrical conductivity, graphite is usually used as a wall material of ion-chamber. Graphene can be a possible alternative to graphite due to its superior electrical conductivity and mechanical integrity. In this study, Monte Carlo simulations for graphene-walled and graphite-walled ion-chambers were performed to characterize their dosimetric properties. A world-first prototype of a graphene ion-chamber was fabricated. A graphene ion-chamber was designed and its prototype was successfully fabricated. The percent depth dose curve calculated by Monte Carlo simulations for a graphene ion-chamber was compatible to the curve using a conventional graphite ion-chamber. Therefore, due to its superior electric conductivity and mechanical integrity, graphene can be a promising alternative to graphite as a wall material of ion-chamber for radiation dosimetry.

  16. The muon chambers take centre stage at CMS

    CERN Multimedia

    2003-01-01

    The CMS muon chambers are now starting to arrive at CERN in significant numbers. All in all, the muon system of the CMS detector will comprise some 1400 of these chambers. Twenty percent of those for the endcaps have already been installed, while the assembly of those for the barrel will start in December.

  17. ALICE Time Projection Chamber (TPC) Readout Sector in Lab

    CERN Multimedia

    2003-01-01

    The Time Projection Chamber (TPC) is the main particle tracking detector in ALICE. Charged particles crossing the gas of the TPC knock electrons out of their atoms, which drift in the eletric field. By measuring the arrival of electrons at the end of the chamber, at segments such as the one shown here, the TPC will reconstruct the paths of the original charged particles.

  18. Chamber personnel's use of Nitrox 50 during hyperbaric oxygen treatment

    DEFF Research Database (Denmark)

    Hansen, Marco Bo; Jansen, Tejs; Sifakis, Michael B.

    2013-01-01

    We aimed to evaluate the feasibility and safety of using Nitrox 50 as breathing gas during attendance in a multiplace hyperbaric chamber.......We aimed to evaluate the feasibility and safety of using Nitrox 50 as breathing gas during attendance in a multiplace hyperbaric chamber....

  19. Synchrotron radiation vacuum chamber installation and beam size

    Energy Technology Data Exchange (ETDEWEB)

    Shleifer, M.

    1985-01-01

    In this paper we address the question of storage ring vacuum chamber placement and its effect on the synchrotron radiation fan obtainable. We consider only horizonal errors and thus treat the problem two-dimensionally. Specifically, we describe the correlation between the parameters of the chamber and its position in the magnet and the size of the fan of radiation emerging from a port.

  20. Use of Makler counting chamber in semen analysis

    OpenAIRE

    友吉, 唯夫; 石田, 章; 金, 哲將

    1988-01-01

    Sperm concentration was measured using Makler counting chamber and compared with the concentration value measured by a classic method. Both values correlated well. The chamber contributes to a speedy, correct and simple semen analysis mainly because of no need of dilution of the semen. Viral infection to the examiner from the semen can also be avoided.

  1. Application of Chaboche Model in Rocket Thrust Chamber Analysis

    Science.gov (United States)

    Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

    2017-06-01

    Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

  2. Some Features of Aerodynamics of Cyclonic Chamber with Free Exit

    Directory of Open Access Journals (Sweden)

    A. N. Orekhov

    2007-01-01

    Full Text Available The paper cites results of an experimental research in aerodynamics of a cyclonic chamber with a free exit that has a large relative length. Distributions of aerodynamic stream characteristics depending on geometry of working volume of the cyclonic chamber are given in the paper. Calculative dependences are proposed in the paper.

  3. Achieving ultrahigh vacuum in an unbaked chamber with glow ...

    Indian Academy of Sciences (India)

    Glow discharge conditioning (GDC) has long been accepted as one of the basic wall conditioning techniques for achieving ultrahigh vacuum in an unbaked chamber. As a part of this fundamental experimental study, a test chamber has been fabricated from stainless steel 304 L with its inner surface electropolished on ...

  4. Determination of the viscous acoustic field for liquid drop positioning/forcing in an acoustic levitation chamber in microgravity

    Science.gov (United States)

    Lyell, Margaret J.

    1992-01-01

    The development of acoustic levitation systems has provided a technology with which to undertake droplet studies as well as do containerless processing experiments in a microgravity environment. Acoustic levitation chambers utilize radiation pressure forces to position/manipulate the drop. Oscillations can be induced via frequency modulation of the acoustic wave, with the modulated acoustic radiation vector acting as the driving force. To account for tangential as well as radial forcing, it is necessary that the viscous effects be included in the acoustic field. The method of composite expansions is employed in the determination of the acoustic field with viscous effects.

  5. Detector Physics of Resistive Plate Chambers

    CERN Document Server

    Lippmann, Christian; Riegler, W

    2003-01-01

    Resistive Plate Chambers (RPCs) are gaseous parallel plate avalanche detectors that implement electrodes made from a material with a high volume resistivity between 10^7 and 10^12 Ohm cm. Large area RPCs with 2mm single gaps operated in avalanche mode provide above 98% efficiency and a time resolution of around 1ns up to a flux of several kHz/cm2. These Trigger RPCs will, as an example, equip the muon detector system of the ATLAS experiment at CERN on an area of 3650m2 and with 355.000 independent read out channels. Timing RPCs with a gas gap of 0.2 to 0.3mm are widely used in multi gap configurations and provide 99% efficiency and time resolution down to 50ps. While their performance is comparable to existing scintillator-based Time-Of-Flight (TOF) technology, Timing RPCs feature a significantly, up to an order of magnitude, lower price per channel. They will for example equip the 176m2 TOF barrel of the ALICE experiment at CERN with 160.000 independent read out cells. RPCs were originally operated in stream...

  6. R3B time projection chamber

    Science.gov (United States)

    Legou, P.

    2012-07-01

    Within the international FAIR project, the R3B collaboration (Reaction studies with Radioactive Relativistic beams) will be in charge of the physics program with secondary beams of energy between 200 and 1500MeV per nucleon. Central to the R3B set-up will be a large-aperture superconducting magnet under construction at CEA-Saclay. An international collaboration has been formed to work on the design of a large time-projection chamber (TPC) to be installed behind this magnet to cover the full phase-space of the charged fragments produced in the target. Within this collaboration, tests of detector prototypes were performed with the heavy-ions beams at GSI Darmstadt. These prototypes were equipped with a gaseous Micromegas detector. Two amplification technologies were tested, either conventional or resistive Micromegas and two construction concepts, bulk-Micromegas or micro-meshes screwed on the PCB. We will present the results of the last beam and the 1m TPC station which will be dedicated to make tests using the real drift distance and compare the performances of micromegas and GEM.

  7. Performance of large area Micro Pixel Chamber

    CERN Document Server

    Nagayoshi, T; Miuchi, K; Ochi, A; Orito, R; Takada, A; Tanimori, T; Ueno, M

    2003-01-01

    A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber (micro-PIC)" has been developed. This detector is based on double sided printed circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with 65536 pixel anodes of 400um pitch on a 100um thick insulating substrate. Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was obtained with argon ethane (8:2) gas mixture. This gain is high enough to detect minimum ionizing particles with such a small electrode pitch. Although several discharges occurred during 65 hours continuous operation, the detectors have kept stable operation with high gain. The micro-PIC is a useful detector for many applications e.g. X-ray, gamma ray, and charged particle imaging. The micro electrode structure allows us to measure directions of primary electrons due to incident X-rays or gamma rays, which provide a strong method for X-ray polarimetry and gamma-ray imaging.

  8. Flow structure of conical distributed multiple gas jets injected into a water chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jiajun; Yu, Yonggang [Nanjing University of Science and Technology, Nanjing (China)

    2017-04-15

    Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure.

  9. Primordial vorticity and gradient expansion

    CERN Document Server

    Giovannini, Massimo

    2012-01-01

    The evolution equations of the vorticities of the electrons, ions and photons in a pre-decoupling plasma are derived, in a fully inhomogeneous geometry, by combining the general relativistic gradient expansion and the drift approximation within the Adler-Misner-Deser decomposition. The vorticity transfer between the different species is discussed in this novel framework and a set of general conservation laws, connecting the vorticities of the three-component plasma with the magnetic field intensity, is derived. After demonstrating that a source of large-scale vorticity resides in the spatial gradients of the geometry and of the electromagnetic sources, the total vorticity is estimated to lowest order in the spatial gradients and by enforcing the validity of the momentum constraint. By acknowledging the current bounds on the tensor to scalar ratio in the (minimal) tensor extension of the $\\Lambda$CDM paradigm the maximal comoving magnetic field induced by the total vorticity turns out to be, at most, of the or...

  10. Local expansions and accretive mappings

    Directory of Open Access Journals (Sweden)

    W. A. Kirk

    1983-01-01

    Full Text Available Let X and Y be complete metric spaces with Y metrically convex, let D⊂X be open, fix u0∈X, and let d(u=d(u0,u for all u∈D. Let f:X→2Y be a closed mapping which maps open subsets of D onto open sets in Y, and suppose f is locally expansive on D in the sense that there exists a continuous nonincreasing function c:R+→R+ with ∫+∞c(sds=+∞ such that each point x∈D has a neighborhood N for which dist(f(u,f(v≥c(max{d(u,d(v}d(u,v for all u,v∈N. Then, given y∈Y, it is shown that y∈f(D iff there exists x0∈D such that for x∈X\\D, dist(y,f(x0≤dist(u,f(x. This result is then applied to the study of existence of zeros of (set-valued locally strongly accretive and ϕ-accretive mappings in Banach spaces

  11. An anechoic chamber facility for investigating aerodynamic noise

    Science.gov (United States)

    Massier, P. F.; Parthasarathy, S. P.

    1972-01-01

    The aerodynamic noise facility was designed to be used primarily for investigating the noise-generating mechanisms of high-temperature supersonic and subsonic jets. The facility consists of an anechoic chamber, an exhaust jet silencer, instrumentation equipment, and an air heater with associated fuel and cooling systems. Compressed air, when needed for jet noise studies, is provided by the wind tunnel compressor facility on a continuous basis. The chamber is 8.1 m long, 5.0 m wide, and 3.0 m high. Provisions have been made for allowing outside air to be drawn into the anechoic chamber in order to replenish the air that is entrained by the jet as it flows through the chamber. Also, openings are provided in the walls and in the ceiling for the purpose of acquiring optical measurements. Calibration of the chamber for noise reflections from the wall was accomplished in octave bands between 31.2 Hz and 32 kHz.

  12. Hermetic Seal Leak Detection Apparatus with Variable Size Test Chamber

    Science.gov (United States)

    Kelley, Anthony R. (Inventor)

    2015-01-01

    The present invention is a versatile hermetic seal leak detection apparatus for testing hermetically sealed containers and devices for leaks without the need to create a custom or specially manufactured testing chamber conforming to the dimensions of the specific object under test. The size of the testing chamber may be mechanically adjusted by the novel use of bellows to reduce and optimize the amount of gas space in a test chamber which surrounds the hermetically sealed object under test. The present invention allows the size of the test chamber to be selectively adjusted during testing to provide an optimum test chamber gas space. The present invention may be further adapted to isolate and test specific portions of the hermetically sealed object under test for leaks.

  13. Multi-chamber nucleic acid amplification and detection device

    Energy Technology Data Exchange (ETDEWEB)

    Dugan, Lawrence

    2017-10-25

    A nucleic acid amplification and detection device includes an amplification cartridge with a plurality of reaction chambers for containing an amplification reagent and a visual detection reagent, and a plurality of optically transparent view ports for viewing inside the reaction chambers. The cartridge also includes a sample receiving port which is adapted to receive a fluid sample and fluidically connected to distribute the fluid sample to the reaction chamber, and in one embodiment, a plunger is carried by the cartridge for occluding fluidic communication to the reaction chambers. The device also includes a heating apparatus having a heating element which is activated by controller to generate heat when a trigger event is detected. The heating apparatus includes a cartridge-mounting section which positioned a cartridge in thermal communication with the heating element so that visual changes to the contents of the reaction chambers are viewable through the view ports.

  14. Design of a Hyperbaric Chamber for Pressure Testing

    Directory of Open Access Journals (Sweden)

    Mohamad Sazali Shahmir Fikhri bin

    2014-07-01

    Full Text Available A hyperbaric chamber is an application of a pressure vessel to test the integrity of components and equipments subjected to high pressure. The chamber comprises of several main parts such as a shell, heads, instrumentation attachments, threaded fasteners and support. This paper describes the design of hyperbaric chamber for pressure testing that compiles to the ASME Boiler and Pressure Vessel code. The design approach adopted is the “design by formula” method. A structural analysis of the hyperbaric chamber with a cylindrical shell and a vertical orientation, based on an operating pressure of 34.5 MPa, was done. The analysis of the stress distribution shows that the normalized principal stresses acting on the chamber are within the yield envelop based on the maximum distortional energy criteria.

  15. Earnings Returns to the British Education Expansion

    Science.gov (United States)

    Devereux, Paul J.; Fan, Wen

    2011-01-01

    We study the effects of the large expansion in British educational attainment that took place for cohorts born between 1970 and 1975. Using the Quarterly Labour Force Survey, we find that the expansion caused men to increase education by about a year on average and gain about 8% higher wages; women obtained a slightly greater increase in education…

  16. Series expansion of the modified Einstein Procedure

    Science.gov (United States)

    Seema Chandrakant Shah-Fairbank

    2009-01-01

    This study examines calculating total sediment discharge based on the Modified Einstein Procedure (MEP). A new procedure based on the Series Expansion of the Modified Einstein Procedure (SEMEP) has been developed. This procedure contains four main modifications to MEP. First, SEMEP solves the Einstein integrals quickly and accurately based on a series expansion. Next,...

  17. Virial expansion coefficients in the harmonic approximation

    DEFF Research Database (Denmark)

    R. Armstrong, J.; Zinner, Nikolaj Thomas; V. Fedorov, D.

    2012-01-01

    The virial expansion method is applied within a harmonic approximation to an interacting N-body system of identical fermions. We compute the canonical partition functions for two and three particles to get the two lowest orders in the expansion. The energy spectrum is carefully interpolated...

  18. Platform Expansion Design as Strategic Choice

    DEFF Research Database (Denmark)

    Staykova, Kalina S.; Damsgaard, Jan

    2016-01-01

    In this paper, we address how the strategic choice of platform expansion design impacts the subse-quent platform strategy. We identify two distinct approaches to platform expansion – platform bun-dling and platform constellations, which currently co-exist. The purpose of this paper is to outline...

  19. The heavy quark expansion of QCD

    Energy Technology Data Exchange (ETDEWEB)

    Falk, A.F. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy

    1997-06-01

    These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs.

  20. Expansion techniques for collisionless stellar dynamical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Meiron, Yohai [Kavli Institute for Astronomy and Astrophysics at Peking University, Beijing 100871 (China); Li, Baile; Holley-Bockelmann, Kelly [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Spurzem, Rainer, E-mail: ymeiron@pku.edu.cn [National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-09-10

    We present graphics processing unit (GPU) implementations of two fast force calculation methods based on series expansions of the Poisson equation. One method is the self-consistent field (SCF) method, which is a Fourier-like expansion of the density field in some basis set; the other method is the multipole expansion (MEX) method, which is a Taylor-like expansion of the Green's function. MEX, which has been advocated in the past, has not gained as much popularity as SCF. Both are particle-field methods and optimized for collisionless galactic dynamics, but while SCF is a 'pure' expansion, MEX is an expansion in just the angular part; thus, MEX is capable of capturing radial structure easily, while SCF needs a large number of radial terms. We show that despite the expansion bias, these methods are more accurate than direct techniques for the same number of particles. The performance of our GPU code, which we call ETICS, is profiled and compared to a CPU implementation. On the tested GPU hardware, a full force calculation for one million particles took ∼0.1 s (depending on expansion cutoff), making simulations with as many as 10{sup 8} particles fast for a comparatively small number of nodes.

  1. Business information query expansion through semantic network

    Science.gov (United States)

    Gong, Zhiguo; Muyeba, Maybin; Guo, Jingzhi

    2010-02-01

    In this article, we propose a method for business information query expansions. In our approach, hypernym/hyponymy and synonym relations in WordNet are used as the basic expansion rules. Then we use WordNet Lexical Chains and WordNet semantic similarity to assign terms in the same query into different groups with respect to their semantic similarities. For each group, we expand the highest terms in the WordNet hierarchies with hypernym and synonym, the lowest terms with hyponym and synonym and all other terms with only synonym. In this way, the contradictory caused by full expansion can be well controlled. Furthermore, we use collection-related term semantic network to further improve the expansion performance. And our experiment reveals that our solution for query expansion can improve the query performance dramatically.

  2. Maxwell superalgebras and Abelian semigroup expansion

    Directory of Open Access Journals (Sweden)

    P.K. Concha

    2014-09-01

    Full Text Available The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2 leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N. Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure.

  3. A plant chamber system with downstream reaction chamber to study the effects of pollution on biogenic emissions

    NARCIS (Netherlands)

    Timovsky, J.; Gankema, Paulien; Pierik, Ronald; Holzinger, Rupert

    2014-01-01

    A system of two plant chambers and a downstream reaction chamber has been set up to investigate the emission of biogenic volatile organic compounds (BVOCs) and possible effects of pollutants such as ozone. The system can be used to compare BVOC emissions from two sets of differently treated plants,

  4. Investigating the thermal systems of a chamber belonging to a dry coke-quenching unit. [Quenching chamber

    Energy Technology Data Exchange (ETDEWEB)

    Grishchenko, A.I.; Ereskovskii, O.S.; Kukhar, N.P.

    1984-01-01

    The thermal system of a quenching chamber is an important parameter describing the functioning of a dry coke quenching device (DCQD) and is a function of the distribution of the temperatures of the coke and the gas relative to the height of the quenching chamber. The present systems of automatic monitoring of the temperature relative to the height of the chamber, in the DCQD's used now, do not provide the information necessary for engineers, concerning the distribution of the temperatures within the chamber. This is due to the difficulty of obtaining this information using the industrial devices available today. Some data on the character of the processes taking place in the chamber can be obtained by measuring the temperature of the quenched coke or the quenching gases at the outlet of the quenching chamber. However, due to the great smoothingout ability of the object (the quenching chamber) and the complicated nature of the processes taking place in it, this information also fails to give a complete picture of the distribution of temperatures in a chamber.

  5. Autoignition Chamber for Remote Testing of Pyrotechnic Devices

    Science.gov (United States)

    Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

    2009-01-01

    The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

  6. Characterization of a CT ionization chamber for radiation field mapping

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana P., E-mail: aperini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Neves, Lucio P., E-mail: lpneves@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Vivolo, Vitor, E-mail: vivolo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Xavier, Marcos, E-mail: mxavier@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil); Khoury, Helen J., E-mail: hjkhoury@gmail.com [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, 50740-540, Recife, PE (Brazil); Caldas, Linda V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Av. Prof. Lineu Prestes 2242, 05508-000, Sao Paulo, SP (Brazil)

    2012-07-15

    A pencil-type ionization chamber, developed at Instituto de Pesquisas Energeticas e Nucleares (IPEN), was characterized with the objective to verify the possibility of its application in radiation field mapping procedures. The characterization tests were evaluated, and the results were satisfactory. The results obtained for the X radiation field mapping with the homemade chamber were compared with those of a PTW Farmer-type chamber (TN 30011-1). The maximum difference observed in this comparison was only 1.25%, showing good agreement. - Highlights: Black-Right-Pointing-Pointer A new ionization chamber was made and tested for radiation field mapping. Black-Right-Pointing-Pointer This ionization chamber was made using only accessible low cost materials. Black-Right-Pointing-Pointer The operational tests were made and the results were within the recommended limits. Black-Right-Pointing-Pointer The field map was compared with a commercial chamber presenting a 1.25% difference. Black-Right-Pointing-Pointer Our chamber presents potential for assurance reliability in calibration procedures.

  7. Aging tests of full scale CMS muon cathode strip chambers

    Energy Technology Data Exchange (ETDEWEB)

    D. Acosta et al.

    2003-10-15

    Two CMS production Cathode Strip Chambers were tested for aging effects in the high radiation environment at the Gamma Irradiation Facility at CERN. The chambers were irradiated over a large area: in total, about 2.1 m{sup 2} or 700 m of wire in each chamber. The 40% Ar+50%CO{sub 2}+10%CF{sub 4} gas mixture was provided by an open-loop gas system for one of the chambers and by closed-loop recirculating gas system for the other. After accumulating 0.3-0.4 C per centimeter of a wire, which is equivalent to operation during about 30-50 years at the peak LHC luminosity, no significant changes in gas gain, chamber efficiency, and wire signal noise were observed for either of the two chambers. The only consistent signs of aging were a small increase in dark current from {approx}2 nA to {approx}10 nA per plane of 600 wires and a decrease of strip-to-strip resistance from 1000 G{Omega} to 10-100 G{Omega}. Disassembly of the chambers revealed deposits on the cathode planes, while the anode wires remained fairly clean.

  8. The evolutionary nature of narratives about expansion and sustenance

    Science.gov (United States)

    Raupach, M. R.

    2014-12-01

    The 200 years since the start of the industrial era has been a period of rapid and almost unbroken economic growth in much of the world, based upon exponentially increasing use of energy and water resources and the atmospheric commons. It is axiomatic that exponential growth cannot continue forever on a finite planet, leading to an emerging collision between the presently irresistible force of economic growth and the immovable reality of the finitude of Planet Earth. This has led to the a contest between two broad narratives about humans and their planet in the 21st century, an "expansion" narrative framed around the paramount need for economic growth, and a "sustenance" narrative framed around the paramount need to protect an increasingly fragile natural world. Many features of recent public discourse, including the acceleration of the news cycle and the echo-chamber effect of interactive social media, have driven these narratives to become progressively more mutually antagonistic and incompatible. Here I explore the idea that narratives (in the sense of stories that empower actions) are meme sequences that evolve through diversification, selection and adaptation. This memetic evolution can be understood and, to some extent, influenced. An analogy might be with the influence exerted by human selection over centuries on the gene pool of domesticated animals and plants. In shaping our shared future, the evolutionary contest between "expansion" and "sustenance" narratives is just as important as the dynamics of the natural world. The future therefore depends upon the evolution of more subtle and resilient narratives about human-earth interactions. A selection test for these narratives is their ability to empower a transition to a society that lives within the means of a finite planet and improves global wellbeing at the same time. My own recent experience is that scientists alone are not very good at shaping narratives to pass this fitness test, and the participation

  9. Angular spectral plane-wave expansion of nonstationary random fields in stochastic mode-stirred reverberation processes.

    Science.gov (United States)

    Arnaut, Luk R

    2010-04-01

    We derive an integral expression for the plane-wave expansion of the time-varying (nonstationary) random field inside a mode-stirred reverberation chamber. It is shown that this expansion is a so-called oscillatory process, whose kernel can be expressed explicitly in closed form. The effect of nonstationarity is a modulation of the spectral density of the field on a time scale that is a function of the cavity relaxation time. It is also shown how the contribution by a nonzero initial value of the field can be incorporated into the expansion. The results are extended to a special class of second-order processes, relevant to the reception of a mode-stirred reverberation field by a device under test with a first-order (relaxation-type) frequency response.

  10. "Flat-Fish" vacuum chamber for the ISR

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    The "Flat-Fish" vacuum chamber was a very special one for the ISR beam intersection I-4, inside the Split-Field Magnet. Technical descriptions are given with pictures 7802042 and 7712182. There were several generations of this chamber. This picture was taken during the last year of ISR operation. See also 7510230X, 7511123X, 7802039, 7802041. A flat-fish type vacuum chamber was also used at I-8, inside the Open Axial Field Magnet (OAFM, experiment 807 on large transverse momentum collision products), see 7901358.

  11. Assembly of Drift Tubes (DT) Chambers at CIEMAT (Madrid)

    CERN Multimedia

    Jesus Puerta-Pelayo

    2003-01-01

    The construction of muon drift tube chambers (DT) has been carried out in four different european institutes: Aachen (Germany), CIEMAT-Madrid (Spain), Legnaro and Turin (Italy), all of them following similar procedures and quality tests. Each chamber is composed by three or two independent units called superlayers, with four layers of staggered drift cells each. The assembly of a superlayer is a succesive glueing of aluminium plates and I-beams with electrodes previously attached, forming a rectangular and gas-tight volume. These pictures illustrate the various processes of material preparation, construction, equipment and assembly of full chambers at CIEMAT (Madrid).

  12. Technology, Applications, and Process Challenges of Dual Chamber Systems.

    Science.gov (United States)

    Werk, Tobias; Ludwig, Imke S; Luemkemann, Joerg; Mahler, Hanns-Christian; Huwyler, Joerg; Hafner, Mathias

    2016-01-01

    Dual-chamber systems provide an option as a drug and device combination product, when home care and emergency lyophilized products are intended. Nevertheless, until today, there are only a few products on the market, due to the challenges and limitations in manufacturability, product formulation, and product stability in a dual-chamber configuration, as well as economic considerations. This review serves to describe currently available dual-chamber systems and to discuss factors to be considered for appropriate selection and establishing fill-finish processes. Copyright © 2016. Published by Elsevier Inc.

  13. Use of a streamer chamber for low energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Van Bibber, K.; Pang, W.; Avery, M.; Bloemhof, E.

    1979-10-01

    A small streamer chamber has been implemented for low energy heavy ion reaction studies at the LBL 88-inch cyclotron. The response of the chamber to light and heavy ions below 35 MeV/nucleon has been examined. The limited sensitivity of light output as a function of ionization works to advantage in recording a wide variety of tracks in the same photograph whose energy loss may vary considerably. Furthermore, as gas targets are attractive for several reasons, we have investigated the suitability of Ar and Xe for use in streamer chambers.

  14. Dark matter searches with PICO bubble chambers: An overview

    Science.gov (United States)

    Harris, Orin; PICO Collaboration

    2017-01-01

    The PICO collaboration uses bubble chambers to search for dark matter, with world-leading sensitivity to the direct-detection of WIMPs with spin-dependent couplings to protons. PICO currently operates a 2 liter (PICO-2L) and a 32 liter (PICO 60) bubble chamber at the SNOLAB deep underground laboratory, and is currently constructing a 40 liter demonstration device that is expected to eliminate an anomalous background that has previously proven significant for the scaling of the bubble chamber technique to a future ton-scale experiment (PICO-500). A discussion of the technology, recent progress, and future plans will be presented.

  15. Modelling of fission chambers in current mode—Analytical approach

    Science.gov (United States)

    Chabod, Sébastien; Fioni, Gabriele; Letourneau, Alain; Marie, Frédéric

    2006-10-01

    A comprehensive theoretical model is proposed to explain the functioning of fission chambers operated in current mode, even in very high neutron fluxes. The calibration curves are calculated as a function of basic physical parameters as fission rate, gas pressure and geometry of the chambers. The output current at saturation is precisely calculated, as well as the maximum voltage to be applied in order to avoid avalanche phenomena. The electric field distortion due to the space charge phenomena is also estimated. Within this model, the characteristic responses of fission chambers are correctly reproduced, in agreement with the experience feedback obtained at the ILL/Grenoble High-Flux Reactor.

  16. A ring-shaped recombination chamber for hadron therapy dosimetry.

    Science.gov (United States)

    Jakubowska, E; Zielczyński, M; Golnik, N; Gryziński, M A; Krzemiński, Ł

    2014-10-01

    An innovative recombination chamber has been designed for estimation of stray radiation doses and quality factors in hadron therapy. The chamber allows for determination of absorbed dose and recombination index of radiation quality in phantoms at small distances from simulated organs. The chamber body and electrodes are ring shaped, so the beam may be directed through the empty centre of the ring. The ionisation of the filling gas is caused by secondary or scattered radiation and can be related to the dose absorbed in the tissues close to the irradiated target volume. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Heat transfer function of the VENUS vertex chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ohama, T.; Ishihara, N.; Yamada, Y.

    1996-05-01

    In order to estimate the temperature distribution in the VENUS vertex chamber at TRISTAN, a heat transfer function has been derived from the temperature information of a beam pipe flange. The function obtained suggests that the temperature of the flange and that in the chamber gas are simply in proportional relation to the equivalent heat input. Consequently, it is possible to easily correct the velocity of drift electrons in the chamber gas on the basis of the temperature distribution patterns, which are calculated from the typical heat input. (author)

  18. Giant negative thermal expansion in magnetic nanocrystals

    Science.gov (United States)

    Zheng, X. G.; Kubozono, H.; Yamada, H.; Kato, K.; Ishiwata, Y.; Xu, C. N.

    2008-12-01

    Most solids expand when they are heated, but a property known as negative thermal expansion has been observed in a number of materials, including the oxide ZrW2O8 (ref. 1) and the framework material ZnxCd1-x(CN)2 (refs 2,3). This unusual behaviour can be understood in terms of low-energy phonons, while the colossal values of both positive and negative thermal expansion recently observed in another framework material, Ag3[Co(CN)6], have been explained in terms of the geometric flexibility of its metal-cyanide-metal linkages. Thermal expansion can also be stopped in some magnetic transition metal alloys below their magnetic ordering temperature, a phenomenon known as the Invar effect, and the possibility of exploiting materials with tuneable positive or negative thermal expansion in industrial applications has led to intense interest in both the Invar effect and negative thermal expansion. Here we report the results of thermal expansion experiments on three magnetic nanocrystals-CuO, MnF2 and NiO-and find evidence for negative thermal expansion in both CuO and MnF2 below their magnetic ordering temperatures, but not in NiO. Larger particles of CuO and MnF2 also show prominent magnetostriction (that is, they change shape in response to an applied magnetic field), which results in significantly reduced thermal expansion below their magnetic ordering temperatures; this behaviour is not observed in NiO. We propose that the negative thermal expansion effect in CuO (which is four times larger than that observed in ZrW2O8) and MnF2 is a general property of nanoparticles in which there is strong coupling between magnetism and the crystal lattice.

  19. On the equisummability of Hermite and Fourier expansions

    Indian Academy of Sciences (India)

    We prove an equisummability result for the Fourier expansions and. Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions. Keywords. Hermite functions; special Hermite expansions; ...

  20. Expansion Coefficient on Oxides and Oxide Ceramics.

    Science.gov (United States)

    1986-05-01

    Classification) EXPANSION COEFFICIENTS ON OXIDES AND OXIDE CERAMICS 12 PFRSONAL AUTHOR(S) Josephine Covino 13a TYPE OF REPORT 13b TIME COVERED 114 DATE OF REPORT...drastically alter expansion properties of oxides. It has been found that fine-grained (᝺ tm) anisotropic ceramic materials, such as hafnium oxide, hafnium ...Gokhale. "Thermal Expansion of Zircon ," Jap. J. AppZ. Phys., 7 (1968), p. 1126. 34 -- ’-a.’! nw-W’W L. .WW U. .PV _ 77 NWC TP 6663 81. J. L. Amoros, M

  1. Some Improved Nonperturbative Bounds for Fermionic Expansions

    Energy Technology Data Exchange (ETDEWEB)

    Lohmann, Martin, E-mail: marlohmann@gmail.com [Universita di Roma Tre, Dipartimento di Matematica (Italy)

    2016-06-15

    We reconsider the Gram-Hadamard bound as it is used in constructive quantum field theory and many body physics to prove convergence of Fermionic perturbative expansions. Our approach uses a recursion for the amplitudes of the expansion, discovered in a model problem by Djokic (2013). It explains the standard way to bound the expansion from a new point of view, and for some of the amplitudes provides new bounds, which avoid the use of Fourier transform, and are therefore superior to the standard bounds for models like the cold interacting Fermi gas.

  2. Thermal expansion: Metallic elements and alloys. [Handbook

    Science.gov (United States)

    Touloukian, Y. S.; Kirby, R. K.; Taylor, R. E.; Desai, P. D.

    1975-01-01

    The introductory sections of the work are devoted to the theory of thermal expansion of solids and to methods for the measurement of the linear thermal expansion of solids (X-ray methods, high speed methods, interferometry, push-rod dilatometry, etc.). The bulk of the work is devoted to numerical data on the thermal linear expansion of all the metallic elements, a large number of intermetallics, and a large number of binary alloy systems and multiple alloy systems. A comprehensive bibliography is provided along with an index to the materials examined.

  3. Microwave-range shielding effectiveness measurements using a dual vibrating intrinsic reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Serra, Ramiro; Schipper, H.

    2012-01-01

    Reverberation chambers create a statistical uniformly distributed field which is very useful for reliable electromagnetic interference measurements. Another advantage of these chambers is the high field strength which can be generated compared to conventional test setups. A reverberation chamber

  4. A cylindrical drift chamber for the measurement of K. -->. pi. nu anti nu

    Energy Technology Data Exchange (ETDEWEB)

    Cresswell, J.V.; Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Khan, N.; Kuno, Y.; Numao, T.

    1987-10-01

    A cylindrical drift chamber has been constructed for the study of the rare kaon decay K+ ..-->.. ..pi../sup +/ nu anti nu. Data from two prototype chambers and initial results from the final chamber are presented.

  5. A cylindrical drift chamber for the measurement of k. -->. pi nu nu. -bar decay

    Energy Technology Data Exchange (ETDEWEB)

    Cresswell, J.V.; Ahmad, S.; Blackmore, E.W.; Bryman, D.A.; Khan, N.; Kuno, Y.; Numao, T.

    1988-02-01

    A cylindrical drift chamber has been constructed for the study of the rare kaon decay K/sup +/ ..-->.. ..pi../sup +/..nu nu..-bar. Data from two prototype chambers and initial results from the final chamber are presented.

  6. Design of a new multi-phase experimental simulation chamber for atmospheric photosmog, aerosol and cloud chemistry research

    Directory of Open Access Journals (Sweden)

    J. Wang

    2011-11-01

    Full Text Available A new simulation chamber has been built at the Interuniversitary Laboratory of Atmospheric Systems (LISA. The CESAM chamber (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber is designed to allow research in multiphase atmospheric (photo- chemistry which involves both gas phase and condensed phase processes including aerosol and cloud chemistry. CESAM has the potential to carry out variable temperature and pressure experiments under a very realistic artificial solar irradiation. It consists of a 4.2 m3 stainless steel vessel equipped with three high pressure xenon arc lamps which provides a controlled and steady environment. Initial characterization results, all carried out at 290–297 K under dry conditions, concerning lighting homogeneity, mixing efficiency, ozone lifetime, radical sources, NOy wall reactivity, particle loss rates, background PM, aerosol formation and cloud generation are given. Photolysis frequencies of NO2 and O3 related to chamber radiation system were found equal to (4.2 × 10−3 s−1 for JNO2 and (1.4 × 10−5 s−1 for JO1D which is comparable to the solar radiation in the boundary layer. An auxiliary mechanism describing NOy wall reactions has been developed. Its inclusion in the Master Chemical Mechanism allowed us to adequately model the results of experiments on the photo-oxidation of propene-NOx-Air mixtures. Aerosol yields for the α-pinene + O3 system chosen as a reference were determined and found in good agreement with previous studies. Particle lifetime in the chamber ranges from 10 h to 4 days depending on particle size distribution which indicates that the chamber can provide high quality data on aerosol aging processes and their effects. Being evacuable, it is possible to generate in this new chamber

  7. Simulation of Wakefield Effect in ILC IR Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Pei, S; Seryi, A.; Raubenheimer, T.O.; /SLAC

    2008-06-26

    To achieve super high luminosity, high current beams with very short bunch length are needed, which carry high intensity EM fields. For ILC, two bunch trains with bunch length of 300 {micro}m and bunch charge of 3.2nC are needed to collide at the IR to achieve the ILC luminosity goals. When the 300 {micro}m bunches pass through the IR chamber, wakefields will be excited, which will cause HOM power flowing through the IR chamber beam pipe to the final doublets due to the high frequency characteristic of the induced wakefields. Since superconducting technology is adopted for the final doublets of ILC BDS, whose operation stability might be affected by the HOM power produced at the IR chamber, quench might happen. In this paper, we did some analytical estimation and numerical simulation on the wakefield effects in ILC IR chamber.

  8. Radon progeny deposition in track-detection diffusion chambers

    CERN Document Server

    Pressyanov, D; Simeonov, G

    1999-01-01

    The sensitivity dependence for cylindrical diffusion chambers that are used for radon track-detection measurements on the deposition fraction of radon progeny atoms has been theoretically studied (sensitivity is the ratio: area track density/integrated sup 2 sup 2 sup 2 Rn activity concentration). Experimentally, the sensitivity values of both the metal- and plastic-made chambers were determined. Results indicate that the experimental sensitivity for metal chambers is in accordance with the theoretical model while a deviation of 15% is observed for plastic chambers. The uncertainty in the sensitivity values that is related to possible variations of the diffusion coefficient for sup 2 sup 1 sup 8 Po atoms was estimated to be less than 10%. (author)

  9. A Temperature-Controlled Chamber Based on Vortex Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Krider, John; Nguyen, Hogan; /Fermilab

    2007-11-01

    We describe the construction and performance of a temperature-controlled chamber, based on a 'vortex' cooler. The chamber is capable of operation between room temperature and -42 C. The only nontrivial infrastructure requirement is dry compressed gas at 100 psi and 8 cfm. The chamber is economical, easy to operate and to build using commercially available parts. Since the refrigerant is compressed air, the chamber has minimal environmental impact. It does not generate mechanical vibrations nor electrical noise. It is suitable for testing electronically sensitive and low-power electronics at cold temperatures. We measured the reserve cooling capacity of the cold plate to be 17 watts at -27 C. At the limiting temperature of -42 C, reserve cooling power reduces to zero.

  10. Charge production in thin gap multi-wire chambers

    CERN Document Server

    Mincer, A I; Goldberg, J J; Gernitzky, Y; Lazic, D; Lupu, N Z; Robins, S; Rozen, Y; Tarem, S

    2000-01-01

    Resistive cathode thin gap chambers (TGCs) have been used as particle detectors in high-energy physics experiments for more than a decade. A quantitative understanding of charge production mechanisms in TGCs has been developed and a simulation program produced to accurately describe the expected response from a chamber as a function of its design and operating parameters. This simulation is based upon a description of the processes of electron cluster production, drift and avalanche effects and space charge contributions from residual ions. Improved measurements of chamber performance are presented, and the parameters of the simulation have been fitted to these data yielding values consistent with estimates based on the physical mechanisms involved. Sensitivity of chamber timing and amplification properties to operating parameters is discussed.

  11. Ultralightweight, Regeneratively Cooled Combustion Chamber for Mars Ascent Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a high-pressure, regeneratively-cooled combustion chamber that uses novel material selection for extreme reductions in mass. These materials are...

  12. Ducted combustion chamber for direct injection engines and method

    Science.gov (United States)

    Mueller, Charles

    2015-03-03

    An internal combustion engine includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore has a piston crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between the piston crown and the flame deck surface. A fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber has at least one nozzle opening configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. At least one duct defined in the combustion chamber between the piston crown and the flame deck surface has a generally rectangular cross section and extends in a radial direction relative to the cylinder bore substantially along the fuel jet centerline.

  13. 'Reading' bubble chamber pictures with the Spiral Reader eyes.

    CERN Multimedia

    1974-01-01

    Interactive techniques were widely used to study bubble chamber pictures. After a visual scanning of the pictures and a vertex measurement on a Shivamatic, the Spiral Reader allowed the track polar coordinates to be easily measured. See photo 7408137X

  14. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems (RCS) for future NASA missions such...

  15. Production and test of the LHCb Muon Chamber

    CERN Multimedia

    2005-01-01

    - The Muon System of LHCb - The Multi-Wire Proportional Chambers for LHCb - Wire tension meter - Wire pitch measurement - Gas leakage test - Test with cosmic rays - Production and test summary - Gap gain uniformity - Production and test summary

  16. Oxford engineering students to study new solutions for vacuum chambers

    CERN Multimedia

    Department of Engineering Science - University of Oxford

    2012-01-01

    In April, eleven engineering science students in their third year at Oxford University were invited here to present their design ideas for new vacuum chamber materials to be used in accelerators. We publish below an abstract of the article that the University of Oxford featured on its website.   The 11 Oxford students who worked at CERN on alternatives to beryllium in vacuum chambers. (Photo courtesy of the Department of Engineering Science, University of Oxford.) Engineering Science students invited to design for CERN’s Large Hadron Collider In April, eleven Engineering Science students in their third year were invited to the CERN laboratory in Geneva to present their ideas for new vacuum chamber designs for the experiments of the Large Hadron Collider (LHC). Their design objectives were to propose alternatives to beryllium – the material used for some of the existing experimental vacuum chambers. Beryllium (chemical element with the symbol Be and atomic number 4) is to...

  17. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems for NASA missions such as Mars Sample...

  18. Repair of isolated double-chambered right ventricle

    Directory of Open Access Journals (Sweden)

    M El Kouache

    2013-01-01

    Full Text Available The finding of a double-chambered right ventricle (DCRV is exceptionally rare as an isolated anomaly. It is a congenital cardiac anomaly in which the right ventricle is separated into two chambers, a proximal high-pressure chamber and a distal low-pressure chamber, by anomalous muscles or fibrous tissues in the right ventricular cavity. We report the case of a 6-year-old infant who was admitted for growth retardation. The patient was diagnosed with an isolated DCRV without any other associated congenital anomalies. The patient underwent a successful cardiac surgical procedure of enlargement repair; he was discharged in good clinical condition with a normal cardiac function.

  19. Radiation Hydrodynamic Parameter Study of Inertial Fusion Energy Reactor Chambers

    Science.gov (United States)

    Sacks, Ryan; Moses, Gregory

    2014-10-01

    Inertial fusion energy reactors present great promise for the future as they are capable of providing baseline power with no carbon footprint. Simulation work regarding the chamber response and first wall insult is performed with the 1-D radiation hydrodynamics code BUCKY. Simulation with differing chamber parameters are implemented to study the effect of gas fill, gas mixtures and chamber radii. Xenon and argon gases are of particular interest as shielding for the first wall due to their high opacity values and ready availability. Mixing of the two gases is an attempt to engineer a gas cocktail to provide the maximum amount of shielding with the least amount of cost. A parameter study of different chamber radii shows a consistent relationship with that of first wall temperature (~1/r2) and overpressure (~1/r3). This work is performed under collaboration with Lawrence Livermore National Laboratory.

  20. Combustion Chamber/Nozzle Assembly and Fabrication Process Therefor

    Science.gov (United States)

    Myers, W. Neill (Inventor); Cornelius, Charles S. (Inventor)

    2000-01-01

    An integral lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its larger end with a rocket body, and terminates at its smaller end in a tube of generally cylindrical contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time.

  1. Fabrication process for combustion chamber/nozzle assembly

    Science.gov (United States)

    Myers, W. Neill (Inventor); Cornelius, Charles S. (Inventor)

    2001-01-01

    An integral, lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its smaller end with a rocket body, and terminates at its larger end in a generally contact contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time.

  2. Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine

    Science.gov (United States)

    Lawrence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.

    2001-01-01

    The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

  3. Effect of Chamber Wall Proximity on Radiometer Force Production (Preprint)

    National Research Council Canada - National Science Library

    Selden, N. P; Gimelshein, N. E; Gimelshein, S. F; Ketsdever, A. D

    2008-01-01

    ... on a given radiometer configuration in both the free molecule and transitional regimes. The contribution of the chamber walls to both the flowfield structure and radiometric force production were examined for helium, argon, and nitrogen test gases...

  4. Magma chamber and mantle reflections - East Pacific Rise

    Science.gov (United States)

    Herron, Thomas J.; Stoffa, Paul L.; Buhl, Peter

    1980-11-01

    A multichannel seismic reflection profile of stacked and migrated common depth point data across the East Pacific Rise near the Siqueiros Fracture Zone supports and extends previous observations (at two crossings 27 to 50 km to the south) of reflections assumed to be from the top of a magma chamber and of reflections from the M-discontinuity. The reflection assumed to be associated with the top of the magma chamber is 1-1/2 to 2 km below the sea floor. The combined results of the three crossings suggest that the chamber is continuous along the Rise crest and that its width, which varies from 2 to 8 km, correlates with the width of the Rise crest as indicated by the bathymetric contours. The reflections from the crust-mantle boundary can be detected beneath the raised axial block of the East Pacific Rise and although weak, can be detected beneath the magma chamber.

  5. Simulation of the heat transfer around the ATLAS muon chambers

    CERN Multimedia

    2005-01-01

    This 2D simulation recently carried out on the ATLAS muon chambers by a small team of CERN engineers specialises in the numerical computation of fluid dynamics, in other words the flow of fluids and heat.

  6. Transport of Na48 Drift Chambers to Dubna

    CERN Multimedia

    GOLOVATYUK, V

    2010-01-01

    On 22 July, in the occasion of the departure of the Na48 Drift Chambers from CERN, Mikhail Itkis (acting Director of the JIINR) and Rolf Heuer (CERN Director General) visited the NA62 experimental area.

  7. Cryogenic Optical Metrology Through a Chamber Window Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase I SBIR project for NASA, Flexure Engineering of Greenbelt, MD will design and develop a system that marries the technologies of Thermal Vacuum Chambers...

  8. Nonlocal electron kinetics and spatial transport in radio-frequency two-chamber inductively coupled plasmas with argon discharges

    Science.gov (United States)

    Li, Hong; Liu, Yang; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian

    2017-06-01

    A two-chamber inductively coupled plasma (ICP) system, in which an expansion region with large volume is attached to a main ICP (driver region with a small vessel), is investigated. In order to give a comprehensive knowledge of this kind of plasma source, the axially and radially resolved measurements of the electron density, effective electron temperature, and electron energy probability function (EEPF) for an argon discharge are systematically conducted by means of Langmuir probe for various powers and gas pressures. Moreover, a hybrid model within COMSOL Multiphysics is employed to validate the experimental results. It is found that the diffusion combined with the nonlocal electron kinetics plays a predominant role in two-chamber ICPs. Along the axial direction, both the electron density and the electron temperature peak at the center of the driver region and they decline towards both sides. The depletion of high-energy tails of EEPFs with axial distance demonstrates the cooling mechanism for energetic electrons in the expansion region. Along the radial direction, the spatial distribution of the electron density exhibits a bell shape for various powers and pressures. However, the radial distribution of the effective electron temperature varies gradually from a convex shape to a concave shape with increasing gas pressure, indicating the transition from nonlocal to local electron kinetics.

  9. Collisional and collisionless expansion of Yukawa balls.

    Science.gov (United States)

    Piel, Alexander; Goree, John A

    2013-12-01

    The expansion of Yukawa balls is studied by means of molecular dynamics simulations of collisionless and collisional situations. High computation speed was achieved by using the parallel computing power of graphics processing units. When the radius of the Yukawa ball is large compared to the shielding length, the expansion process starts with the blow-off of the outermost layer. A rarefactive wave subsequently propagates radially inward at the speed of longitudinal phonons. This mechanism is fundamentally different from Coulomb explosions, which employ a self-similar expansion of the entire system. In the collisionless limit, the outer layers carry away most of the available energy. The simulations are compared with analytical estimates. In the collisional case, the expansion process can be described by a nonlinear diffusion equation that is a special case of the porous medium equation.

  10. TA53:19 Reverb Chamber Quick-Look

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-19

    Within Building 19 of TA-53, a screen room has been evaluated for use as a reverb chamber (with deep gratitude to Dale Dalmas and Greg Dale for their assistance). With minimal additional sealing of the chamber, we expect the Q to increase even more, and thus field levels for the same RF source power. Future studies need to determine leakage field levels, which will define maximum achievable field levels.

  11. Anechoic Chambers: Aerospace Applications. (Latest Citations from the Aerospace Database)

    Science.gov (United States)

    1996-01-01

    The bibliography contains citations concerning the design, development, performance, and applications of anechoic chambers in the aerospace industry. Anechoic chamber testing equipment, techniques for evaluation of aerodynamic noise, microwave and radio antennas, and other acoustic measurement devices are considered. Shock wave studies on aircraft models and components, electromagnetic measurements, jet flow studies, and antenna radiation pattern measurements for industrial and military aerospace equipment are discussed. (Contains 50-250 citations and includes a subject term index and title list.)

  12. Wideband MIMO Channel Capacity Analysis in Multiprobe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyosti, Pekka; Nielsen, Jesper Ødum

    2016-01-01

    This paper discusses over the air (OTA) testing for multiple input multiple output (MIMO) capable terminals with emphasis on wideband MIMO channel capacity analysis in a multi-probe anechoic chamber setup. In the literature, the spatial correlation simulation accuracy at the receiver (Rx) side has...... in a practical multi-probe anechoic chamber setup. The capacity simulation accuracy is shown to be a valid measure to determine the test area size....

  13. Identification of proteins in fluid collected from nerve regeneration chambers

    Directory of Open Access Journals (Sweden)

    Ye Yilin

    2014-01-01

    Full Text Available We examined whether there are novel neurotrophic factors (NTFs in nerve regeneration conditioned fluid (NRCF. Nerve regeneration chamber models were established in the sciatic nerves of 25 New Zealand rabbits, and NRCF was extracted from the chambers l week postoperatively. Proteins in NRCF were separated by native polyacrylamide gel electrophoresis (PAGE, and Western blot and ELISA were used to identify the proteins. A novel NTF was identified in a protein fraction corresponding to 220 kDa.

  14. Gridded Ionization Chamber; Camara de ionizacion con reja

    Energy Technology Data Exchange (ETDEWEB)

    Manero Amoros, F.

    1962-07-01

    In the present paper the working principles of a gridded ionization chamber are given, and all the different factors that determine its resolution power are analyzed in detail. One of these devices, built in the Physics Division of the JEN and designed specially for use in measurements of alpha spectroscopy, is described. finally the main applications, in which the chamber can be used, are shown. (Author) 17 refs.

  15. Nuclear Design Considerations for Z-IFE Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R; Schmitt, R C; Abbott, R P; Latkowski, J F; Reyes, S

    2005-02-02

    Z-pinch driven IFE (Z-IFE) requires the design of a repetitive target insertion system that allows coupling of the pulsed power to the target with adequate standoff, and a chamber that can withstand blast and radiation effects from large yield targets. The present strategy for Z-IFE is to use high yield targets ({approx}2-3 GJ/shot), low repetition rate per chamber ({approx}0.1 Hz), and 10 chambers per power plant. In this study, we propose an alternative power plant configuration that uses very high yield targets (20 GJ/shot) in a single chamber operating at 0.1 Hz. A thick-liquid-wall chamber is proposed to absorb the target emission (x-rays, debris and neutrons) and mitigate the blast effects on the chamber wall. The target is attached to the end of a conical shaped Recyclable Transmission Line (RTL) made from a solid coolant (e.g., frozen flibe), or a material that is easily separable from the coolant (e.g., steel). The RTL/target assembly is inserted through a single opening at the top of the chamber for each shot. This study looks at the RTL material choice from a safety and environmental point of view. Materials were assessed according to waste disposal rating (WDR) and contact dose rate (CDR). Neutronics calculations, using the TART2002 Monte Carlo code from Lawrence Livermore National Laboratory (LLNL), were performed for the RTL and Z-IFE chamber, and key results reported here.

  16. Imploded test-chamber for an ISR intersection

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    At the ISR intersection points the vacuum chambers had to be as "transparent" as possible, for the p-p collision product particles to reach the detectors with minimum hindrance. This meant the choice of a light, yet very strong, metal; minimum thickness; and corrugation for mechanical strength. The test-chamber seen here was made of 0.6 mm thick corrugated titanium, obviously not strong enough to withstand the atmospheric pressure.

  17. Immunoglobulin response to bluetongue virus soluble antigen in subcutaneous chambers.

    Science.gov (United States)

    Hajer, I; Jochim, M M; Lauerman, L H

    1977-06-01

    Group-specific antibodies were produced by inoculation of bluetongue virus soluble antigen into polyethylene chambers implanted subcutaneously in 8 rabbits and 2 sheep. For comparison, 5 rabbits and 1 sheep were inoculated intramuscularly with the soluble antigen in Freund's complete adjuvant. Antibodies present in the serum and chamber fluids were detected by the agar gel precipitin or serum-neutralization tests, qualitatively examined by immunoelectrophoresis and immunofluorescence, and quantitated by electroimmunodiffusion.

  18. Central tracking chamber with inflated cathode-strip foils

    Science.gov (United States)

    Blackmore, E. W.; Bryman, D. A.; Kuno, Y.; Lim, C.; Numao, T.; Padley, P.; Redlinger, G.; Soluk, R.; McPherson, R. A.

    1998-02-01

    A new cylindrical low-mass central drift chamber has been constructed for the K+ → π +ν overlineν experiment at BNL (E787). The chamber consists of twelve layers of axial wire cells and six layers of thin cathode-strip foils, four of which are supported by differential gas pressure. The momentum resolution (RMS) for muons and pions in the range 150-250 MeV/ c is found to be about 0.9%.

  19. Investigation Deviation Flame in Micro-Turbine's Combustion Chamber with Numerical Simulation

    OpenAIRE

    Sedighi. Mohammad; Aghnia. Mehdi; Neisi. Walid; Hosseini. Hiwa

    2016-01-01

    This study is conducted regarding the investigation of the reasons causing defects in GTCP85-180 combustion chamber. The combustion chamber in this micro-turbine is single can side type. In spite of geometric symmetry in air inlets of the combustion chamber, the air inlet path to the combustion chamber is not symmetrical. Also, in the secondary zone of this combustion chamber, there is an igniter with considerable size. Investigations on several defected combustion chambers show burnings and ...

  20. Thermal expansion of doped lanthanum gallates

    Indian Academy of Sciences (India)

    Thermal expansion of several compositions of Sr and Mg-doped LaGaO3 including an -site deficient composition (La0.9Sr0.1)0.98(Ga0.8Mg0.2)O2.821 were measured in the temperature range from 298 to 1273 K. The effect of doping on thermal expansion was studied by varying the composition at one site of the ...

  1. Expansion and rupture of charged microcapsules

    OpenAIRE

    Datta, Sujit S.; Abbaspourrad, Alireza; Weitz, David A

    2014-01-01

    We study the deformations of pH-responsive spherical microcapsules -- micrometer-scale liquid drops surrounded by thin, solid shells -- under the influence of electrostatic forces. When exposed to a large concentration of NaOH, the microcapsules become highly charged, and expand isotropically. We find that the extent of this expansion can be understood by coupling electrostatics with shell theory; moreover, the expansion dynamics is well described by Darcy's law for fluid flow through the mic...

  2. Tissue expansion: Concepts, techniques and unfavourable results

    OpenAIRE

    Milind S Wagh; Varun Dixit

    2013-01-01

    The phenomenon of tissue expansion is observed in nature all the time. The same properties of the human skin to stretch and expand and yield extra skin if placed under continuous stress over a prolonged period of time has been utilised for reconstructive purposes with the help of a silicon balloon inserted under the skin and progressively filled with saline. The technique of tissue expansion is now more than three decades old and has been a value addition to our armamentarium in reconstructiv...

  3. Negative thermal expansion in framework compounds

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... We have studied negative thermal expansion (NTE) compounds with chemi- cal compositions of NX2O8 and NX2O7 (N=Zr, Hf and X=W, Mo, V) and M2O (M=Cu, Ag) using the techniques of inelastic neutron scattering and lattice dynamics. There is a large variation in the negative thermal expansion ...

  4. Russia and the Future Expansion of NATO

    Science.gov (United States)

    2011-03-24

    2001 that he did not intend to let enlargement undermine the potential for U.S.- Russia cooperation. Later in the summer, Putin took a further step...St ra te gy R es ea rc h Pr oj ec t RUSSIA AND THE FUTURE EXPANSION OF NATO BY COLONEL RADEK CERNY Czech Army DISTRIBUTION STATEMENT A...Strategy Research Project 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Russia and the Future Expansion of NATO 5a. CONTRACT

  5. The. delta. expansion and local gauge invariance

    Energy Technology Data Exchange (ETDEWEB)

    Bender, C.M. (Department of Physics, Washington University, St. Louis, Missouri 63130 (US)); Cooper, F. (Department of Physics, Brown University, Providence, Rhode Island 02912 Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexic o 87545); Milton, K.A. (Department of Physics, The Ohio State University, Columbus, Ohio 43210 Department of Physics and Astronomy, University of Oklahoma, Norman, Oklaho ma 73019)

    1989-08-15

    A recently proposed approximation method, called the {delta} expansion, was introduced in the context of a self-interacting scalar field theory. This approximation method offers the hope of obtaining nonperturbative information about a quantum field theory using perturbative techniques. In this paper we extend formally the {delta}-expansion methods to field theories having local gauge symmetry. We then compute the anomaly in the Schwinger model.

  6. Stochastic quantization and 1/N expansion

    Energy Technology Data Exchange (ETDEWEB)

    Brunelli, J.C. [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Mendes, R.S. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1992-10-01

    We study the 1/N expansion of field theories in the stochastic quantization method of Parisi and Wu using the supersymmetric functional approach. This formulation provides a systematic procedure to implement the 1/N expansion which resembles the ones used in the equilibrium. The 1/N perturbation theory for the non linear sigma model in two dimensions is worked out as an example. (author). 19 refs., 5 figs.

  7. Fixed Point Theorems for Times Reasonable Expansive Mapping

    Directory of Open Access Journals (Sweden)

    Chen Chunfang

    2008-01-01

    Full Text Available Abstract Based on previous notions of expansive mapping, times reasonable expansive mapping is defined. The existence of fixed point for times reasonable expansive mapping is discussed and some new results are obtained.

  8. Energy Loss to Coaxial Vacuum Chambers in LEP and LHC

    CERN Document Server

    Gluckstern, R L

    1996-01-01

    In many hig-energy storage rings the beam chamber is connected to a separate pump chamber by a metallic wall with many holes or slots whic permits passage of the rest gas. In LEP, the pump chamber contains a metallic 'negstrip' pump, and thereby becomes a coazial transmission line. Also in LHC, a coaxial line is formed by the 'liner' and the surrounding cold vacuum chamber which it shields from heating by sznchrotron radiation. Since the phase velocity of electro-magnetic fields in a coax line is close to light velocity, the fields will be almost in sznchronism with the particle beam and the pump chamber, which may result in a large resistive impedance and could lead to isntability, loss of beam energy, and excessive heating of the chamber walls. Here we estimate the rate of field buildup analytically, and in a subsequent report we will compare these results with numerical computations using 3-D computer codes. The results are tested for diagnostic purposes on a 'slot coupler' with short and wide holes design...

  9. Oxide Protective Coats for Ir/Re Rocket Combustion Chambers

    Science.gov (United States)

    Fortini, Arthur; Tuffias, Robert H.

    2003-01-01

    An improved material system has been developed for rocket engine combustion chambers for burning oxygen/ hydrogen mixtures or novel monopropellants, which are highly oxidizing at operating temperatures. The baseline for developing the improved material system is a prior iridium/rhenium system for chambers burning nitrogen tetroxide/monomethyl hydrazine mixtures, which are less oxidizing. The baseline combustion chamber comprises an outer layer of rhenium that provides structural support, plus an inner layer of iridium that acts as a barrier to oxidation of the rhenium. In the improved material system, the layer of iridium is thin and is coated with a thermal fatigue-resistant refractory oxide (specifically, hafnium oxide) that serves partly as a thermal barrier to decrease the temperature and thus the rate of oxidation of the rhenium. The oxide layer also acts as a barrier against the transport of oxidizing species to the surface of the iridium. Tests in which various oxygen/hydrogen mixtures were burned in iridium/rhenium combustion chambers lined with hafnium oxide showed that the operational lifetimes of combustion chambers of the improved material system are an order of magnitude greater than those of the baseline combustion chambers.

  10. Expansive Soil Crack Depth under Cumulative Damage

    Directory of Open Access Journals (Sweden)

    Bei-xiao Shi

    2014-01-01

    Full Text Available The crack developing depth is a key problem to slope stability of the expansive soil and its project governance and the crack appears under the roles of dry-wet cycle and gradually develops. It is believed from the analysis that, because of its own cohesion, the expansive soil will have a certain amount of deformation under pulling stress but without cracks. The soil body will crack only when the deformation exceeds the ultimate tensile strain that causes cracks. And it is also believed that, due to the combined effect of various environmental factors, particularly changes of the internal water content, the inherent basic physical properties of expansive soil are weakened, and irreversible cumulative damages are eventually formed, resulting in the development of expansive soil cracks in depth. Starting from the perspective of volumetric strain that is caused by water loss, considering the influences of water loss rate and dry-wet cycle on crack developing depth, the crack developing depth calculation model which considers the water loss rate and the cumulative damages is established. Both the proposal of water loss rate and the application of cumulative damage theory to the expansive soil crack development problems try to avoid difficulties in matrix suction measurement, which will surely play a good role in promoting and improving the research of unsaturated expansive soil.

  11. Uncertainty Quantification of Non-linear Oscillation Triggering in a Multi-injector Liquid-propellant Rocket Combustion Chamber

    Science.gov (United States)

    Popov, Pavel; Sideris, Athanasios; Sirignano, William

    2014-11-01

    We examine the non-linear dynamics of the transverse modes of combustion-driven acoustic instability in a liquid-propellant rocket engine. Triggering can occur, whereby small perturbations from mean conditions decay, while larger disturbances grow to a limit-cycle of amplitude that may compare to the mean pressure. For a deterministic perturbation, the system is also deterministic, computed by coupled finite-volume solvers at low computational cost for a single realization. The randomness of the triggering disturbance is captured by treating the injector flow rates, local pressure disturbances, and sudden acceleration of the entire combustion chamber as random variables. The combustor chamber with its many sub-fields resulting from many injector ports may be viewed as a multi-scale complex system wherein the developing acoustic oscillation is the emergent structure. Numerical simulation of the resulting stochastic PDE system is performed using the polynomial chaos expansion method. The overall probability of unstable growth is assessed in different regions of the parameter space. We address, in particular, the seven-injector, rectangular Purdue University experimental combustion chamber. In addition to the novel geometry, new features include disturbances caused by engine acceleration and unsteady thruster nozzle flow.

  12. Negative thermal expansion materials: technological key for control of thermal expansion

    Directory of Open Access Journals (Sweden)

    Koshi Takenaka

    2012-01-01

    Full Text Available Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.

  13. Design and construction of an inexpensive homemade plant growth chamber.

    Science.gov (United States)

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  14. Design and construction of an inexpensive homemade plant growth chamber.

    Directory of Open Access Journals (Sweden)

    Fumiaki Katagiri

    Full Text Available Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W x 1.8 m (D x 2 m (H, providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant

  15. Development of secondary chamber for tar cracking–improvement of wood pyrolysis performance in pre-vacuum chamber

    Science.gov (United States)

    Siahaan, S.; Homma, H.; Homma, H.

    2018-02-01

    Energy crisis and global warming, in other words, climate change are critical topics discussed in various parts of the world. Global warming primarily result from too much emission of carbon dioxide (CO2) in the atmosphere. To mitigate global warming, or climate change and improve electrification in rural areas, wood pyrolysis technology is developed in a laboratory scale, of which gases are directly applicable to the gas engine generator. Our laboratory has developed a prototype of wood pyrolysis plant with a pre-vacuum chamber. However, tar yield was around 40 wt% of feedstock. This research aims to reduce tar yield by secondary tar cracking. For the secondary tar cracking, a secondary pre-vacuum chamber is installed after primary pre-vacuum chamber. Gases generated in the primary pre-vacuum chamber are lead into the secondary chamber that is heated up to 1000 K. This paper reports performance of the secondary chamber for secondary tar cracking in homogeneous mode and heterogeneous mode with char.

  16. Promoted-Combustion Chamber with Induction Heating Coil

    Science.gov (United States)

    Richardson, Erin; Hagood, Richard; Lowery, Freida; Herald, Stephen

    2006-01-01

    An improved promoted-combustion system has been developed for studying the effects of elevated temperatures on the flammability of metals in pure oxygen. In prior promoted-combustion chambers, initial temperatures of metal specimens in experiments have been limited to the temperatures of gas supplies, usually near room temperature. Although limited elevated temperature promoted-combustion chambers have been developed using water-cooled induction coils for preheating specimens, these designs have been limited to low-pressure operation due to the hollow induction coil. In contrast, the improved promoted-combustion chamber can sustain a pressure up to 10 kpsi (69 MPa) and, through utilization of a solid induction coil, is capable of preheating a metal specimen up to its melting point [potentially in excess of 2,000 F (approximately equal to 1,100 C)]. Hence, the improved promoted combustion chamber makes a greater range of physical conditions and material properties accessible for experimentation. The chamber consists of a vertical cylindrical housing with an inner diameter of 8 in. (20.32 cm) and an inner height of 20.4 in. (51.81 cm). A threaded, sealing cover at one end of the housing can be unscrewed to gain access for installing a specimen. Inlet and outlet ports for gases are provided. Six openings arranged in a helical pattern in the chamber wall contain sealed sapphire windows for viewing an experiment in progress. The base of the chamber contains pressure-sealed electrical connectors for supplying power to the induction coil. The connectors feature a unique design that prevents induction heating of the housing and the pressure sealing surfaces; this is important because if such spurious induction heating were allowed to occur, chamber pressure could be lost. The induction coil is 10 in. (25.4 cm) long and is fitted with a specimen holder at its upper end. At its lower end, the induction coil is mounted on a ceramic base, which affords thermal insulation to

  17. Dark matter limits froma 15 kg windowless bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Szydagis, Matthew Mark [Univ. of Chicago, IL (United States)

    2011-03-01

    The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determined data cuts. The history of COUPP, including its earliest prototypes and latest results, is briefly discussed in this thesis. The feasibility of a new, windowless bubble chamber concept simpler and more inexpensive in design is discussed here as well. The dark matter limits achieved with a 15 kg windowless chamber, larger than any previous COUPP chamber (2 kg, 4 kg), are presented. Evidence of the greater radiopurity of synthetic quartz compared to natural is presented using the data from this 15 kg device, the first chamber to be made from synthetic quartz. The effective reconstruction of the three-dimensional positions of bubbles in a highly distorted optical field, with ninety-degree bottom lighting similar to cloud chamber lighting, is demonstrated. Another innovation described in this thesis is the use of the sound produced by bubbles recorded by an array of piezoelectric sensors as the primary means of bubble detection. In other COUPP chambers, cameras have been used as the primary trigger. Previous work on bubble acoustic signature differentiation using piezos is built upon in order to further demonstrate the ability to discriminate between alpha- and neutron-induced events.

  18. Soil Greenhouse Gas Flux Measurements with Automated and Manual Static Chambers, Forced Diffusion Chamber, and Concentration Profiles

    Science.gov (United States)

    Ruan, L.; Oikawa, P. Y.; Géli, M.; Verfaillie, J. G.; Sturtevant, C. S.; Knox, S. H.; Nickerson, N.; McArthur, G.; Creelman, C.; Saad, N.; Alstad, K. P.; Arata, C.; Baldocchi, D. D.; Silver, W. L.

    2014-12-01

    Accurate measurements of soil greenhouse gas fluxes are critical for determining the role of ecosystem dynamics, both natural and managed, in climate change. We compared concentration profile methods with static, forced diffusion, and automated flux chambers using a combination of infrared gas analyzers (IRGA), gas chromatography, and cavity ring-down laser absorption spectroscopy (Picarro G2508) during field campaigns in managed ecosystems in California. At a drained peatland pasture site, we observed large differences between methods (fluxes ranged between 2-15 μmol CO2 m-2 s-1). However, low temporal/high spatial replication measurements (manual LI6400 chamber measurements; n=6 collars) encompassed the full range of CO2 fluxes observed across all other methods. This suggests that the majority of variability in CO2 emissions was due to high spatial variation in soil respiration and not due to methodological differences across measurement systems. At a dry upland pasture site, water, nitrate solution and manure were applied during the experimental period to expand the range of greenhouse fluxes. Preliminary results showed good agreement of gas fluxes between static and automatic chamber sampling. We observed large CO2 and N2O fluxes after manure application with both methods. The two chamber types were highly significantly correlated for N2O (slope=0.74, r2=0.94). Mean CH4 fluxes measured by static chambers was -0.36 μg cm-2 h-1, similar to the -0.57 μg cm-2 h-1 measured by the automatic chamber and Picarro analyzer during the study period. Overall, our results suggest that both automated and static chamber methods are in good agreement, but automated chambers are advantageous for capturing diel dynamics and pulse responses to experimental treatments. Our results also highlight the importance of spatial replication, which can be difficult to achieve using expensive automated chambers. We suggest future research efforts to seek a combination of high spatially

  19. Mapping Brazilian Cropland Expansion, 2000-2013

    Science.gov (United States)

    Zalles, V.; Hansen, M.; Potapov, P.

    2016-12-01

    Brazil is one of the world's leading producers and exporters of agricultural goods. Despite undergoing significant increases in its cropland area in the last decades, it remains one of the countries with the most potential for further agricultural expansion. Most notably, the expansion in production areas of commodity crops such as soybean, corn, and sugarcane has become the leading cause of land cover conversion in Brazil. Natural land covers, such as the Amazon and Cerrado forests, have been negatively affected by this agricultural expansion, causing carbon emissions, biodiversity loss, altered water cycles, and many other disturbances to ecosystem services. Monitoring of change in cropland area extent can provide relevant information to decision makers seeking to understand and manage land cover change drivers and their impacts. In this study, the freely-available Landsat archive was leveraged to produce a large-scale, methodologically consistent map of cropland cover at 30 m. resolution for the entire Brazilian territory in the year 2000. Additionally, we mapped cropland expansion from 2000 to 2013, and used statistical sampling techniques to accurately estimate cropland area per Brazilian state. Using the Global Forest Change product produced by Hansen et al. (2013), we can disaggregate forest cover loss due to cropland expansion by year, revealing spatiotemporal trends that could advance our understanding of the drivers of forest loss.

  20. Supercritical flow characteristics at abrupt expansion structure

    Science.gov (United States)

    Lim, Jia Jun; Puay, How Tion; Zakaria, Nor Azazi

    2017-10-01

    When dealing with the design of a hydraulic structure, lateral expansion is often necessary for flow emerging at high velocity served as a cross-sectional transition. If the abrupt expansion structure is made to diverge rapidly, it will cause the major part of the flow fail to follow the boundaries. If the transition is too gradual, it will result in a waste of structural material. A preliminary study on the flow structure near the expansion and its relationship with flow parameter is carried out in this study. A two-dimensional depth-averaged model is developed to simulate the supercritical flow at the abrupt expansion structure. Constrained Interpolation Profile (CIP) scheme (which is of third order accuracy) is adopted in the numerical model. Results show that the flow structure and flow characteristics at the abrupt expansion can be reproduced numerically. The validation of numerical result is done against analytical studies. The result from numerical simulation showed good agreement with the analytical solution.

  1. Design and testing of a model CELSS chamber robot

    Science.gov (United States)

    Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; McCarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

    1994-08-01

    A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system

  2. Design and testing of a model CELSS chamber robot

    Science.gov (United States)

    Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; Mccarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

    1994-01-01

    A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system

  3. Forecasting magma-chamber rupture at Santorini volcano, Greece.

    Science.gov (United States)

    Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

    2015-10-28

    How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011-2012 unrest period, that the measured 0.02% increase in volume of Santorini's shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano.

  4. On the acoustic wedge design and simulation of anechoic chamber

    Science.gov (United States)

    Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

    2016-10-01

    This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

  5. Design of ITER neutron monitor using micro fission chambers

    Energy Technology Data Exchange (ETDEWEB)

    Nishitani, Takeo; Ebisawa, Katsuyuki; Ando, Toshiro; Kasai, Satoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Johnson, L.C.; Walker, C.

    1998-08-01

    We are designing micro fission chambers, which are pencil size gas counters with fissile material inside, to be installed in the vacuum vessel as neutron flux monitors for ITER. We found that the {sup 238}U micro fission chambers are not suitable because the detection efficiency will increase up to 50% in the ITER life time by breading {sup 239}Pu. We propose to install {sup 235}U micro fission chambers on the front side of the back plate in the gap between adjacent blanket modules and behind the blankets at 10 poloidal locations. One chamber will be installed in the divertor cassette just under the dome. Employing both pulse counting mode and Campbelling mode in the electronics, we can accomplish the ITER requirement of 10{sup 7} dynamic range with 1 ms temporal resolution, and eliminate the effect of gamma-rays. We demonstrate by neutron Monte Carlo calculation with three-dimensional modeling that we avoid those detection efficiency changes by installing micro fission chambers at several poloidal locations inside the vacuum vessel. (author)

  6. Transfer Chamber for DBD Surface Treatment and Analysis

    Science.gov (United States)

    Faust, Jessica; Gershman, Sophia; Daniels, Ryan

    2012-10-01

    Materials that are hydrophobic, smooth, and have low surface tension lead to poor adhesion for printing and coating. Surface modification using atmospheric pressure dielectric barrier discharge (DBD) improves adhesion by activating the surface, increasing its roughness and functionalizing. We have constructed and tested a DBD discharge system that uses a 15kV, 800-1350Hz pulsed dc source and a mixture of gasses at 300-600Torr. Treated surfaces are studied using X-ray photoelectron spectroscopy, Auger electron spectroscopy, and other methods that require high vacuum environment. We designed a portable transfer chamber to move the sample from the atmospheric pressure treatment chamber to a high vacuum surface analysis chamber with minimal interaction with the environment. The transfer chamber was designed to meet the specific requirements of each system; a bellows drive and sample holder to manually move the sample into the transfer chamber; the ability to fill with pure nitrogen gas to prevent contamination of the sample surface; constructed to withstand a range of pressures from 300 to 10-8Torr; the ability to connect compatibly with each system. Proper surface characterization of the sample is crucial to designing an effective treatment system.

  7. Prediction of temperature front in a gas turbine combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, F.Z.; Kubiak, J.; Gonzalez, G.; Urquiza, G. [Universidad Autonoma del Estado de Morelos, Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Cuernavaca, Morelos (Mexico)

    2005-06-01

    Numerical computation has been applied to investigate the temperature field in a gas turbine combustion chamber. The simulation assumed that pressure imbalance conditions of air flow between primary and secondary inlets occur. The combustion chamber under study is part of a 70 MW gas turbine from an operating combined cycle power plant. The combustion was simulated with normal fuel-air flow rate assuming stoichiometric conditions. Under these conditions characteristic temperature and pressure fields were obtained provided equity of boundary conditions at air inlets applies. However, with pressure distribution imbalances of the order of 3 kPa between primary and secondary air inlets, excessive heating in regions other than the combustion chamber core were obtained. Over heating in these regions helped to explain what was observed to produce permanent damage to auxiliary equipment surrounding the combustion chamber core, like the cross flame pipes. It is observed that high temperatures which normally develop in the central region of the combustion chamber may reach other surrounding upstream regions by modifying slightly the air pressure. Microscope scanning of the damaged pipes confirmed that the material was exposed to high temperatures such as predicted through the numerical computation. (Author)

  8. Inertial confinement fusion reaction chamber and power conversion system study

    Energy Technology Data Exchange (ETDEWEB)

    Maya, I.; Schultz, K.R.; Battaglia, J.M.; Buksa, J.J.; Creedson, R.L.; Erlandson, O.D.; Levine, H.E.; Roelant, D.F.; Sanchez, H.W.; Schrader, S.A.

    1984-09-01

    GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li/sub 2/O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li/sub 2/O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li/sub 2/O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive.

  9. Bluetooth Communication Interface for EEG Signal Recording in Hyperbaric Chambers.

    Science.gov (United States)

    Pastena, Lucio; Formaggio, Emanuela; Faralli, Fabio; Melucci, Massimo; Rossi, Marco; Gagliardi, Riccardo; Ricciardi, Lucio; Storti, Silvia F

    2015-07-01

    Recording biological signals inside a hyperbaric chamber poses technical challenges (the steel walls enclosing it greatly attenuate or completely block the signals as in a Faraday cage), practical (lengthy cables creating eddy currents), and safety (sparks hazard from power supply to the electronic apparatus inside the chamber) which can be overcome with new wireless technologies. In this technical report we present the design and implementation of a Bluetooth system for electroencephalographic (EEG) recording inside a hyperbaric chamber and describe the feasibility of EEG signal transmission outside the chamber. Differently from older systems, this technology allows the online recording of amplified signals, without interference from eddy currents. In an application of this technology, we measured EEG activity in professional divers under three experimental conditions in a hyperbaric chamber to determine how oxygen, assumed at a constant hyperbaric pressure of 2.8 ATA , affects the bioelectrical activity. The EEG spectral power estimated by fast Fourier transform and the cortical sources of the EEG rhythms estimated by low-resolution brain electromagnetic analysis were analyzed in three different EEG acquisitions: breathing air at sea level; breathing oxygen at a simulated depth of 18 msw, and breathing air at sea level after decompression.

  10. Low-Cost, High-Performance Combustion Chamber

    Science.gov (United States)

    Fortini, Arthur J.

    2015-01-01

    Ultramet designed and fabricated a lightweight, high-temperature combustion chamber for use with cryogenic LOX/CH4 propellants that can deliver a specific impulse of approx.355 seconds. This increase over the current 320-second baseline of nitrogen tetroxide/monomethylhydrazine (NTO/MMH) will result in a propellant mass decrease of 55 lb for a typical lunar mission. The material system was based on Ultramet's proven oxide-iridium/rhenium architecture, which has been hot-fire tested with stoichiometric oxygen/hydrogen for hours. Instead of rhenium, however, the structural material was a niobium or tantalum alloy that has excellent yield strength at both ambient and elevated temperatures. Phase I demonstrated alloys with yield strength-to-weight ratios more than three times that of rhenium, which will significantly reduce chamber weight. The starting materials were also two orders of magnitude less expensive than rhenium and were less expensive than the C103 niobium alloy commonly used in low-performance engines. Phase II focused on the design, fabrication, and hot-fire testing of a 12-lbf thrust class chamber with LOX/CH4, and a 100-lbf chamber for LOX/CH4. A 5-lbf chamber for NTO/MMH also was designed and fabricated.

  11. An optical imaging system for window chambers in MRI system

    Science.gov (United States)

    Lin, Yuxiang; Salek, Mir F. S.; Jennings, Nicki; Gmitro, Arthur F.

    2008-02-01

    Window chambers are support structures implanted in the dorsal skin fold of a rodent model. Optical imaging of window chambers has been used in many basic cancer and vascular biology studies. We have recently shown that this technique can be extended to MRI by using plastic rather than metal window chambers. Here we describe a system for simultaneous optical and MR imaging of the window chambers. It provides many possibilities for independent cross validation of the measurements of one modality from the other. In the system, a GRIN lens images the tissue to the distal end of a coherent imaging fiber bundle, which relays this image to a camera system located outside the magnet room. Both trans- and epi-illumination are provided to this system. Light sources are located outside the magnet room and the light is delivered through fiber optics. A group of fibers are used to deliver white light from under the window chamber for standard transmission imaging, while another single fiber delivers the laser light from the top to induce fluorescence. An appropriate bandpass emission filter is inserted between the lenses at the camera end for fluorescence imaging. Results of simultaneously optical and MR imaging of tumor and vessel are presented.

  12. Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

    Science.gov (United States)

    Shen, Fei-Ran; Kuang, Hao; Hu, Feng-Xia; Wu, Hui; Huang, Qing-Zhen; Liang, Fei-Xiang; Qiao, Kai-Ming; Li, Jia; Wang, Jing; Liu, Yao; Zhang, Lei; He, Min; Zhang, Ying; Zuo, Wen-Liang; Sun, Ji-Rong; Shen, Bao-Gen

    2017-10-01

    Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn-Co-Ge-In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE owing to a martensitic magnetostructural transition. The major finding is that the thermal expansion behavior can be totally controlled by modulating the crystallinity degree and phase transition from atomic scale. Self-compensation effect leads to ultra-low thermal expansion with a linear expansion coefficient as small as +0.68 × 10-6/K over a wide temperature range around room temperature. The present study opens an avenue to reach ZTE particularly from the large class of giant NTE materials based on phase transition.

  13. Expansions and Extensions : Ergodic, combinatorial and geometric properties of β-expansions with arbitrary digits

    NARCIS (Netherlands)

    Kalle, C.C.C.J.

    2009-01-01

    Let beta be a real number bigger than 1 and A a finite set of arbitrary real numbers. A beta-expansion with digits in A of a real number x is an expression for x by an infinite sum of fractions with powers of beta in the denominators and elements from A in the numerators. Such expansions can be

  14. [Forum on tissue expansion. Expansion of the scalp. Surgical techniques and clinical applications].

    Science.gov (United States)

    Foyatier, J L; Delay, E; Comparin, J P; Latarjet, J; Masson, C L

    1993-02-01

    Repair of all forms of alopecia is one of the principal applications of scalp expansion. The authors have inserted 400 expansion prostheses, including 20 in the scalp. The surgical technique, choice of material and various types of flaps are described and illustrated by clinical cases of extensive alopecia.

  15. Anisotropic thermal expansion in flexible materials

    Science.gov (United States)

    Romao, Carl P.

    2017-10-01

    A definition of the Grüneisen parameters for anisotropic materials is derived based on the response of phonon frequencies to uniaxial stress perturbations. This Grüneisen model relates the thermal expansion in a given direction (αi i) to one element of the elastic compliance tensor, which corresponds to the Young's modulus in that direction (Yi i). The model is tested through ab initio prediction of thermal expansion in zinc, graphite, and calcite using density functional perturbation theory, indicating that it could lead to increased accuracy for structurally complex systems. The direct dependence of αi i on Yi i suggests that materials which are flexible along their principal axes but rigid in other directions will generally display both positive and negative thermal expansion.

  16. Extrudate Expansion Modelling through Dimensional Analysis Method

    DEFF Research Database (Denmark)

    A new model framework is proposed to correlate extrudate expansion and extrusion operation parameters for a food extrusion cooking process through dimensional analysis principle, i.e. Buckingham pi theorem. Three dimensionless groups, i.e. energy, water content and temperature, are suggested...... to describe the extrudates expansion. From the three dimensionless groups, an equation with three experimentally determined parameters is derived to express the extrudate expansion. The model is evaluated with whole wheat flour and aquatic feed extrusion experimental data. The average deviations...... of the correlation are respectively 5.9% and 9% for the whole wheat flour and the aquatic feed extrusion. An alternative 4-coefficient equation is also suggested from the 3 dimensionless groups. The average deviations of the alternative equation are respectively 5.8% and 2.5% in correlation with the same set...

  17. Reduction of fan noise in an anechoic chamber by reducing chamber wall induced inlet flow disturbances

    Science.gov (United States)

    Dittmar, J. H.; Mackinnon, M. J.; Woodward, R. P.

    1978-01-01

    The difference between the flight and ground static noise of turbofan engines has been identified as a significant problem in engine noise testing. The additional noise for static testing has been attributed to inlet flow disturbances or turbulence interacting with the fan rotor. In an attempt to determine a possible source of inflow disturbances entering fans tested in the Lewis Research Center anechoic chamber the inflow field was studied using potential flow analysis. These potential flow calculations indicated that there was substantial flow over the wall directly behind the fan inlet that could produce significant inflow disturbances. Fan noise tests were run with various extensions added to the fan inlet to move the inlet away from this backwall and thereby reduce the inlet flow disturbances. Significant noise reductions were observed with increased inlet length. Over 5 dB reduction of the blade passage tone sound power level was observed between the shortest and longest inlets at 90% fan speed and the first overtone was reduced 9 dB. High frequency broadband noise was also reduced.

  18. In-situ high field strength testing using a transportable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2008-01-01

    A reverberation chamber can create very high fieldstrength with moderate input power. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. In the case of a stepper motor, the field is stable for some time, and this type of reverberation chamber is called

  19. In-situ high field strength testing using a transportable reverberation chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2008-01-01

    A reverberation chamber can create very high field strength with moderate input power. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. In the case of a stepper motor, the field is stable for some time, and this type of reverberation chamber is called

  20. Comparison of static chambers to measure CH4 emissions from soils

    NARCIS (Netherlands)

    Pihlatie, M.K.; Christiansen, J.R.; Aaltonen, H.; Korhonen, J.F.J.; Nordbo, A.; Rasilo, T.; Benanti, G.; Giebels, M.; Helmy, M.; Sheehy, J.; Jones, S.; Juszczak, R.; Klefoth, R.R.; Lobo-do-Vale, R.; Rosa, A.P.; Schreiber, P.; Serca, D.; Vicca, S.; Wolf, B.; Pumpanen, J.

    2013-01-01

    The static chamber method (non-flow-through-non-steady-state chambers) is the most common method to measure fluxes of methane (CH4) from soils. Laboratory comparisons to quantify errors resulting from chamber design, operation and flux calculation methods are rare. We tested fifteen chambers against

  1. Rapid palatal expansion: the role of microcirculation.

    Science.gov (United States)

    Bilello, G; Currò, G; Messina, P; Scardina, G

    2015-08-01

    Transverse palate modifications fall under expansive orthopedic therapy of the upper maxilla. The only practical approach to the problem on the transverse plane is that of performing the expansion of the maxillary arch through an opening of the median palatal suture. It is important to understand the changes of the vascular network in midpalatal suture following the starting of rapid maxillary expansion. It is critical to maintain the blood supply and circulation for the osteogenesis and bone remodeling after the expansion. The aim of this research was to evaluate the effects of rapid orthopedic expansion (REP) at the microcirculatory level through capillaroscopic examination. Fifteen patients in their developing years between 9 and 15 years of age (average age 12.16 years) were examined. The application of the REP was the first step in the planning of orthopedic-orthodontic treatment which foresaw further stages in the odonto-osseous movement. The method of Biomicroscopic Video-Imaging of the microcirculation of oral mucosa is performed through the technique of computerized capillaroscopy and the related software. From the results it is evident that immediately after achieving the expansion of the upper maxilla (t1), a slight decrease in the number of vessels per mm² can be observed. In addition, a slight ectasia can be observed in these vessels in comparison to t0. Comparing the videocapillaroscopic images of t1 and t2, an increase in the capillaries per mm² can be observed. Ectasia of the capillaries, though subject to strictly individual variables, can be considered perfectly normal and it is compatible with the normal biology and physiology of vessel microcirculation.

  2. Longitudinal expansion of field line dipolarization

    Science.gov (United States)

    Saka, O.; Hayashi, K.

    2017-11-01

    We examine the substorm expansions that started at 1155 UT 10 August 1994 in the midnight sector focusing on the longitudinal (eastward) expansion of field line dipolarization in the auroral zone. Eastward expansion of the dipolarization region was observed in all of the H, D, and Z components. The dipolarization that started at 1155 UT (0027 MLT) from 260° of geomagnetic longitude (CMO) expanded to 351°(PBQ) in about 48 min. The expansion velocity was 0.03-0.04°/s, or 1.9 km/s at 62°N of geomagnetic latitude. The dipolarization region expanding to the east was accompanied by a bipolar event at the leading edge of the expansion in latitudes equatorward of the westward electrojet (WEJ). In the midnight sector at the onset meridian, the Magnetospheric Plasma Analyzer (MAP) on board geosynchronous satellite L9 measured electrons and ions between 10 eV and 40 keV. We conclude from the satellite observations that this dipolarization was characterized by the evolution of temperature anisotropies, an increase of the electron and ion temperatures, and a rapid change in the symmetry axis of the temperature tensor. The field line dipolarization and its longitudinal expansion were interpreted in terms of the slow MHD mode triggered by the current disruption. We propose a new magnetosphere-ionosphere coupling (MI-coupling) mechanism based on the scenario that transmitted westward electric fields from the magnetosphere in association with expanding dipolarization produced electrostatic potential (negative) in the ionosphere through differences in the mobility of collisional ions and collisionless electrons. The field-aligned currents that emerged from the negative potential region are arranged in a concentric pattern around the negative potential region, upward toward the center and downward on the peripheral.

  3. Parabolic cyclinder functions : examples of error bounds for asymptotic expansions

    NARCIS (Netherlands)

    R. Vidunas; N.M. Temme (Nico)

    2002-01-01

    textabstractSeveral asymptotic expansions of parabolic cylinder functions are discussedand error bounds for remainders in the expansions are presented. Inparticular Poincaré-type expansions for large values of the argument$z$ and uniform expansions for large values of the parameter areconsidered.

  4. Soft Manifold Dynamics behind Negative Thermal Expansion

    Science.gov (United States)

    Schlesinger, Z.; Rosen, J. A.; Hancock, J. N.; Ramirez, A. P.

    2008-07-01

    Minimal models are developed to examine the origin of large negative thermal expansion in underconstrained systems. The dynamics of these models reveals how underconstraint can organize a thermodynamically extensive manifold of low-energy modes which not only drives negative thermal expansion but extends across the Brillioun zone. Mixing of twist and translation in the eigenvectors of these modes, for which in ZrW2O8 there is evidence from infrared and neutron scattering measurements, emerges naturally in our model as a signature of the dynamics of underconstraint.

  5. Air expansion in the water rocket

    CERN Document Server

    Romanelli, Alejandro; Madina, Federico González

    2012-01-01

    We study the thermodynamics of the water rocket in the thrust phase, taking into account the expansion of the air with water vapor, vapor condensation and the energy taken from the environment. We set up a simple experimental device with a stationary bottle and verified that the gas expansion in the bottle is well approximated by a polytropic process $PV^\\beta$= constant, where the parameter $\\beta$ depends on the initial conditions. We find an analytical expression for $\\beta $ that only depends on the thermodynamic initial conditions and is in good agreement with the experimental results.

  6. NATO Expansion and Alternative Future Security Alignments,

    Science.gov (United States)

    1995-04-01

    International Security," a joint paper by the Institute for USA and Canada and the Center for Naval Analysis, June 1992. 11. Malcolm Mackintosh , "Reform in the...former Under Secretary of Defense for Policy Fred C. Ikle, who opposes NATO expansion, has observed that "This remedy may seem all the more urgent as...opposition to NATO expansion include Fred C. Ikl6, former Under Secretary of Defense for Policy Charles Kupchan, a former member of the U.S. National

  7. Large J expansion in ABJM theory revisited.

    Science.gov (United States)

    Dimov, H; Mladenov, S; Rashkov, R C

    Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.

  8. The Monetary Policy – Restrictive or Expansive?

    Directory of Open Access Journals (Sweden)

    Adam Szafarczyk

    2007-12-01

    Full Text Available The monetary policy plays an important role in macroeconomic policy of government. There is a question concerning type of this policy ñ expansive or restrictive (easy or tidy monetary policy. Unfortunately, we have a lot of criteria. Each of them gives us other answer. So due to equitation of Irving Fisher we have dominantly expansive monetary policy. This same situation exists when we use nominal value of rediscount interest rate of central bank. Opposite result appears when we use real value of this interest rate or level of obligatory reserve. Taking under consideration liquidity on money market we know, that level of interest rate is too high.  

  9. Scenarios of Expansion to Electric Generation Capacity

    Directory of Open Access Journals (Sweden)

    José Somoza-Cabrera

    2017-06-01

    Full Text Available We show the building scenarios of expansion to electric generation capacity enough to supply the demand to 2050. We were using the LEAP facility (Long-range Energy Alternatives Planning System, to simulate dispatch of electricity at minimum cost. Finally, we show the cost-benefice analysis of the technologies availability, included externality and CO2 emission limited. However that we included the externals cost in this analysis, it results insufficient to closed gap between fossil and renewable technologies of electric generation. Nevertheless, in some opportunities the renewable options had very important participations in the minimal cost scenario of expansion.

  10. Expansion of the whole wheat flour extrusion

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    2008-01-01

    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters. Us....... Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%....

  11. Characteristics of an anechoic chamber for fan noise testing

    Science.gov (United States)

    Wazyniak, J. A.; Shaw, L. M.; Essary, J. D.

    1977-01-01

    Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the 1420-m (50,000-ft) chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models with 0.51-m (20-in) diameters are electrically driven to 20,600 rpm in either the inlet mode (drawing air from the chamber) or exhaust mode (discharging air into the chamber) to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested, the JT8D Refan, are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

  12. New Materials for Vacuum Chambers in High Energy Physics

    CERN Document Server

    Garion, Cédric

    2014-01-01

    Vacuum chambers must fulfil ultra-high vacuum requirements while withstanding thermo-mechanical loads. This is particularly true in high energy particle accelerator where interactions of particles with matter may induce thermal load, material activation, background… The choice of the material of the vacuum chamber is crucial for the final application. Metals such as stainless steel, copper and aluminium are usually used. Even with outstanding mechanical and physical properties, beryllium is used for very specific applications because of its cost and toxicity.Ceramics such as alumina are usually used for fast magnet vacuum chambers. With the next generation of high energy physics accelerator generation such as CLIC and TLEP, the problematic of high cyclic thermal load induced by synchrotron radiation is raised. This paper aims at defining some figures of merit of different materials with respect to several load scenarios and presents briefly their vacuum compatibility.

  13. Thermal comfort of dual-chamber ski gloves

    Science.gov (United States)

    Dotti, F.; Colonna, M.; Ferri, A.

    2017-10-01

    In this work, the special design of a pair of ski gloves has been assessed in terms of thermal comfort. The glove 2in1 Gore-Tex has a dual-chamber construction, with two possible wearing configurations: one called “grip” to maximize finger flexibility and one called “warm” to maximize thermal insulation in extremely cold conditions. The dual-chamber gloves has been compared with two regular ski gloves produced by the same company. An intermittent test on a treadmill was carried out in a climatic chamber: it was made of four intense activity phases, during which the volunteer ran at 9 km/h on a 5% slope for 4 minutes, spaced out by 5-min resting phases. Finger temperature measurements were compared with the thermal sensations expressed by two volunteers during the test.

  14. Growth of hollow cell spheroids in microbead templated chambers.

    Science.gov (United States)

    Wang, Eddie; Wang, Dong; Geng, Andrew; Seo, Richard; Gong, Xiaohua

    2017-10-01

    Cells form hollow, spheroidal structures during the development of many tissues, including the ocular lens, inner ear, and many glands. Therefore, techniques for in vitro formation of hollow spheroids are valued for studying developmental and disease processes. Current in vitro methods require cells to self-organize into hollow morphologies; we explored an alternative strategy based on cell growth in predefined, spherical scaffolds. Our method uses sacrificial, gelatin microbeads to simultaneously template spherical chambers within a hydrogel and deliver cells into the chambers. We use mouse lens epithelial cells to demonstrate that cells can populate the internal surfaces of the chambers within a week to create numerous hollow spheroids. The platform supports manipulation of matrix mechanics, curvature, and biochemical composition to mimic in vivo microenvironments. It also provides a starting point for engineering organoids of tissues that develop from hollow spheroids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J F; Abbott, R P; Aceves, S; Anklam, T; Badders, D; Cook, A W; DeMuth, J; Divol, L; El-Dasher, B; Farmer, J C; Flowers, D; Fratoni, M; ONeil, R G; Heltemes, T; Kane, J; Kramer, K J; Kramer, R; Lafuente, A; Loosmore, G A; Morris, K R; Moses, G A; Olson, B; Pantano, C; Reyes, S; Rhodes, M; Roe, K; Sawicki, R; Scott, H; Spaeth, M; Tabak, M; Wilks, S

    2010-11-30

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated design that meets all of these requirements is described herein.

  16. Development and validation of inexpensive, automated, dynamic flux chambers

    Directory of Open Access Journals (Sweden)

    B. B. Almand-Hunter

    2015-01-01

    Full Text Available We developed and validated an automated, inexpensive, and continuous multiple-species gas-flux monitoring system that can provide data for a variety of relevant atmospheric pollutants, including O3, CO2, and NOx. Validation consisted of conducting concurrent gas-phase dry-deposition experiments, using both dynamic flux chambers and an eddy-covariance system, in a grassy clearing in the Duke Forest (Chapel Hill, NC. Experiments were carried out in June and September under a variety of meteorological conditions. Ozone-deposition measurements from the two methods matched very well (4–10% difference in mean flux rate when the leaf-area index (LAI inside the chambers was representative of the average LAI in the field. The dynamic flux chambers can be considered an accurate measurement system under these conditions.

  17. OPAL Central Detector (Including vertex, jet and Z chambers)

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the different parts of the tracking system. (This piece includes the vertex, jet and Z chambers) In the picture above, the central detector is the piece being removed to the right.

  18. Materials screening chamber for testing materials resistance to atomic oxygen

    Science.gov (United States)

    Pippin, H. G.; Carruth, Ralph

    1989-01-01

    A unique test chamber for exposing material to a known flux of oxygen atoms is described. The capabilities and operating parameters of the apparatus include production of an oxygen atom flux in excess of 5 x 10 to the 16th atoms/sq cm-sec, controlled heating of the sample specimen, RF circuitry to contain the plasma within a small volume, and long exposure times. Flux measurement capabilities include a calorimetric probe and a light titration system. Accuracy and limitations of these techniques are discussed. An extension to the main chamber to allow simultaneous ultraviolet and atomic oxygen exposure is discussed. The oxygen atoms produced are at thermal energies. Sample specimens are maintained at any selected temperature between ambient and 200 C, to within + or - 2 C. A representative example of measurements made using the chamber is presented.

  19. Streamlined Calibration of the ATLAS Muon Spectrometer Precision Chambers

    CERN Document Server

    Levin, DS; The ATLAS collaboration; Dai, T; Diehl, EB; Ferretti, C; Hindes, JM; Zhou, B

    2009-01-01

    The ATLAS Muon Spectrometer is comprised of nearly 1200 optically Monitored Drifttube Chambers (MDTs) containing 354,000 aluminum drift tubes. The chambers are configured in barrel and endcap regions. The momentum resolution required for the LHC physics reach (dp/p = 3% and 10% at 100 GeV and 1 TeV) demands rigorous MDT drift tube calibration with frequent updates. These calibrations (RT functions) convert the measured drift times to drift radii and are a critical component to the spectrometer performance. They are sensitive to the MDT gas composition: Ar 93%, CO2 7% at 3 bar, flowing through the detector at arate of 100,000 l hr−1. We report on the generation and application of Universal RT calibrations derived from an inline gas system monitor chamber. Results from ATLAS cosmic ray commissioning data are included. These Universal RTs are intended for muon track reconstuction in LHC startup phase.

  20. Continuous flow, explosives vapor generator and sensor chamber

    Science.gov (United States)

    Collins, Greg E.; Giordano, Braden C.; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D.; Tucker, John E.; Malito, Michael; Eversole, Jay D.; Rose-Pehrsson, Susan

    2014-05-01

    A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

  1. Single chamber microbial fuel cell with Ni-Co cathode

    Science.gov (United States)

    Włodarczyk, Barbara; Włodarczyk, Paweł P.; Kalinichenko, Antonina

    2017-10-01

    The possibility of wastewater treatment and the parallel energy production using the Ni-Co alloy as cathode catalyst for single chamber microbial fuel cells is presented in this research. The research included a preparation of catalyst and comparison of COD, NH4+ and NO3- reduction in the reactor without aeration, with aeration and with using a single chamber microbial fuel cell with Ni-Co cathode. The reduction time for COD with the use of microbial fuel cell with the Ni-Co catalyst is similar to the reduction time with aeration. The current density (2.4 A·m-2) and amount of energy (0.48 Wh) obtained in MFC is low, but the obtained amount of energy allows elimination of the energy needed for reactor aeration. It has been shown that the Ni-Co can be used as cathode catalyst in single chamber microbial fuel cells.

  2. Evaluation of ion chamber dependent correction factors for ionisation chamber dosimetry in proton beams using a Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Palmans, H. [Ghent Univ. (Belgium). Dept. of Biomedical Physics; Verhaegen, F.

    1995-12-01

    In the last decade, several clinical proton beam therapy facilities have been developed. To satisfy the demand for uniformity in clinical (routine) proton beam dosimetry two dosimetry protocols (ECHED and AAPM) have been published. Both protocols neglect the influence of ion chamber dependent parameters on dose determination in proton beams because of the scatter properties of these beams, although the problem has not been studied thoroughly yet. A comparison between water calorimetry and ionisation chamber dosimetry showed a discrepancy of 2.6% between the former method and ionometry following the ECHED protocol. Possibly, a small part of this difference can be attributed to chamber dependent correction factors. Indications for this possibility are found in ionometry measurements. To allow the simulation of complex geometries with different media necessary for the study of those corrections, an existing proton Monte Carlo code (PTRAN, Berger) has been modified. The original code, that applies Mollire`s multiple scattering theory and Vavilov`s energy straggling theory, calculates depth dose profiles, energy distributions and radial distributions for pencil beams in water. Comparisons with measurements and calculations reported in the literature are done to test the program`s accuracy. Preliminary results of the influence of chamber design and chamber materials on dose to water determination are presented.

  3. Safety-Enclosure System For MOCVD Process Chamber

    Science.gov (United States)

    Singletery, James, Jr.; Velasquez, Hugo; Warner, Joseph

    1995-01-01

    Safety-enclosure system filled with nitrogen surrounds reaction chamber in which metallo-organic chemical vapor deposition (MOCVD) performed. Designed to protect against explosions and/or escaping toxic gases and particulates. Gas-purification subsystem ensures during loading and unloading of process materials, interior of MOCVD chamber exposed to less than 1 ppm of oxygen and less than 5 ppm of water in nitrogen atmosphere. Toxic byproducts of MOCVD process collected within inert atmosphere. Enclosure strong enough to contain any fragments in unlikely event of explosion.

  4. Performance of the CMS Cathode Strip Chambers with Cosmic Rays

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; Zoeller, M H; Aldaya Martin, M; Behrens, U; Borras, K; Campbell, A; Castro, E; Dammann, D; Eckerlin, G; Flossdorf, A; Flucke, G; Geiser, A; Hatton, D; Hauk, J; Jung, H; Kasemann, M; Katkov, I; Kleinwort, C; Kluge, H; Knutsson, A; Kuznetsova, E; Lange, W; Lohmann, W; Mankel, R; Marienfeld, M; Meyer, A B; Miglioranzi, S; Mnich, J; Ohlerich, M; Olzem, J; Parenti, A; Rosemann, C; Schmidt, R; Schoerner-Sadenius, T; Volyanskyy, D; Wissing, C; Zeuner, W D; Autermann, C; Bechtel, F; Draeger, J; Eckstein, D; Gebbert, U; Kaschube, K; Kaussen, G; Klanner, R; Mura, B; Naumann-Emme, S; Nowak, F; Pein, U; Sander, C; Schleper, P; Schum, T; Stadie, H; Steinbrück, G; Thomsen, J; Wolf, R; Bauer, J; Blüm, P; Buege, V; Cakir, A; Chwalek, T; De Boer, W; Dierlamm, A; Dirkes, G; Feindt, M; Felzmann, U; Frey, M; Furgeri, A; Gruschke, J; Hackstein, C; Hartmann, F; Heier, S; Heinrich, M; Held, H; Hirschbuehl, D; Hoffmann, K H; Honc, S; Jung, C; Kuhr, T; Liamsuwan, T; Martschei, D; Mueller, S; Müller, Th; Neuland, M B; 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Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns.

  5. Measuring oxygen tension in the anterior chamber of rabbits.

    Science.gov (United States)

    McLaren, J W; Dinslage, S; Dillon, J P; Roberts, J E; Brubaker, R F

    1998-09-01

    Measuring the concentration of oxygen in the aqueous humor without penetrating the eye would provide a new dimension in understanding aqueous humor and corneal dynamics. In this study a preinvasive method was developed for determining the cameral oxygen concentration in anesthetized rabbits by measuring the excited-state lifetime of a phosphorescent dye. A scanning ocular fluorometer was designed to excite phosphorescence with a brief flash of light and to measure the decay of luminescence for as long as 1000 microsec after excitation. The measurement window was scanned through the depth of the anterior chamber or fixed at the mid-anterior chamber. A depot of the phosphorescent dye Pd-uroporphyrin was injected into the vitreous of eight pigmented rabbits, and within a few days the dye was measurable in the anterior chamber. The excited-state lifetime of this dye is inversely correlated to oxygen concentration and was calibrated by measuring the lifetime of dye in cuvettes equilibrated with oxygen-nitrogen mixtures. Oxygen tensions were determined from lifetimes measured in the open eye, under a polymethylmethacrylate (PMMA) contact lens, under two oxygen-permeable contact lenses, and immediately after lid closure. Oxygen tension in the mid-anterior chamber before placing a PMMA contact lens was 23 +/- 3 mm Hg (mean +/- SD; n = 6). After 20 minutes of PMMA lens wear, oxygen tension decreased to 4 +/- 2 mm Hg. When the focal diamond was scanned through the anterior chamber, oxygen tension was 24 +/- 5 mm Hg near the corneal endothelium and decreased to 17 +/- 8 mm Hg near the crystalline lens. Under the PMMA contact lens this gradient reversed: Oxygen tensions near the endothelium and lens were 3 +/- 2 mm Hg and 6 +/- 2 mm Hg, respectively. Lid closure for 10 minutes or longer decreased the mid-anterior chamber oxygen tension from 21 +/- 2 mm Hg (n = 19 measurements from seven animals) to 10 +/- 3 mm Hg (n = 15 measurements from five animals). Measuring excited

  6. Characterization of a free air ionization chamber for low energies

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natalia F.; Xavier, Marcos; Vivolo, Vitor; Caldas, Linda V.E., E-mail: nsilva@ipen.br, E-mail: mxavier@ipen.br, E-mail: vivolo@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition. (author)

  7. Resistive Plate Chambers for Imaging Calorimetry - the DHCAL

    CERN Document Server

    Repond, Jose

    2014-01-01

    The DHCAL, the Digital Hadron Calorimeter, is a prototype calorimeter based on Resistive Plate Chambers (RPCs). The design emphasizes the imaging capabilities of the detector in an effort to optimize the calorimeter for the application of Particle Flow Algorithms (PFAs) to the reconstruction of hadronic jet energies in a colliding beam environment. The readout of the chambers is segmented into 1 x 1 cm2 pads, each read out with a 1-bit (single threshold) resolution. The prototype with approximately 500,000 readout channels underwent extensive testing in both the Fermilab and CERN test beams. This talk presents preliminary findings from the analysis of data collected at the test beams.

  8. Resistive Plate Chambers for imaging calorimetry — The DHCAL

    Science.gov (United States)

    Repond, J.

    2014-09-01

    The DHCAL — the Digital Hadron Calorimeter — is a prototype calorimeter based on Resistive Plate Chambers (RPCs). The design emphasizes the imaging capabilities of the detector in an effort to optimize the calorimeter for the application of Particle Flow Algorithms (PFAs) to the reconstruction of hadronic jet energies in a colliding beam environment. The readout of the chambers is segmented into 1 × 1 cm2 pads, each read out with a 1-bit (single threshold) resolution. The prototype with approximately 500,000 readout channels underwent extensive testing in both the Fermilab and CERN test beams. This talk presents preliminary findings from the analysis of data collected at the test beams.

  9. The optical system for the Big European Bubble Chamber

    CERN Document Server

    Harigel, G G

    1977-01-01

    The optical system for the new giant bubble chamber, built for the European Organization for Nuclear Research (CERN), consists of four sets of fisheye windows, each equipped with a wide-angle lens which has an aperture angle of 108 degrees , while the fifth set has a periscope for visual observation of the chamber interior. Each of the fisheye sets is assembled from three hemispherical windows. The largest hemisphere is made from Schott BK7 glass and is exposed to the temperature of liquid hydrogen. The entire optical system has been operated successfully for the past 4 years. (13 refs).

  10. Micro acoustic resonant chambers for heating/agitating/mixing (MARCHAM)

    Science.gov (United States)

    Sherrit, Stewart; Noell, Aaron C.; Fisher, Anita M.; Takano, Nobuyuki; Grunthaner, Frank

    2016-04-01

    A variety of applications require the mixing and/or heating of a slurry made from a powder/fluid mixture. One of these applications, Sub Critical Water Extraction (SCWE), is a process where water and an environmental powder sample (sieved soil, drill cuttings, etc.) are heated in a sealed chamber to temperatures greater than 200 degrees Celsius by allowing the pressure to increase, but without reaching the critical point of water. At these temperatures, the ability of water to extract organics from solid particulate increases drastically. This paper describes the modeling and experimentation on the use of an acoustic resonant chamber which is part of an amino acid detection instrument called Astrobionibbler [Noell et al. 2014, 2015]. In this instrument we use acoustics to excite a fluid- solid fines mixture in different frequency/amplitude regimes to accomplish a variety of sample processing tasks. Driving the acoustic resonant chamber at lower frequencies can create circulation patterns in the fluid and mixes the liquid and fines, while driving the chamber at higher frequencies one can agitate the fluid and powder and create a suspension. If one then drives the chamber at high amplitude at resonance heating of the slurry occurs. In the mixing and agitating cell the particle levitation force depends on the relative densities and compressibility's of the particulate and fluid and on the kinetic and potential energy densities associated with the velocity and pressure fields [Glynne-Jones, Boltryk and Hill 2012] in the cell. When heating, the piezoelectric transducer and chamber is driven at high power in resonance where the solid/fines region is modelled as an acoustic transmission line with a large loss component. In this regime, heat is pumped into the solution/fines mixture and rapidly heats the sample. We have modeled the piezoelectric transducer/chamber/ sample using Mason's equivalent circuit. In order to assess the validity of the model we have built and

  11. Cosmic ray tests of large area Multigap Resistive Plate Chambers

    CERN Document Server

    An, S; Kim, J; Williams, M C S; Zichichi, A; Zuyeuski, R

    2007-01-01

    We have built Multigap Resistive Plate Chambers (MRPC) with six gas gaps and an active area of . The signals are generated on 2.5 cm wide copper pickup strips; these are read out at each end thus allowing the position of the hit along the strip to be obtained from the time difference. Using three of these chambers we have set up a cosmic tracking system in a similar manner as planned for the Extreme Energy Events (EEE) project. The details of the set-up are presented in this paper. In addition we discuss the time and position resolution of these MRPCs measured using cosmic rays.

  12. Precise gain measurement of the LHCb muon chambers

    CERN Document Server

    Dané, E; Pinci, D; Sarti, A

    2006-01-01

    The muon detector of the LHCb experiment, which will operate at the Large Hadron Collider (LHC) at CERN, consists of five muon tracking stations placed along the beam axis and equipped mainly with multi-wire proportional chambers (MWPC). In the present paper we report the results of a precise measurement of the gain of the MWPC’s as a function of the anode voltage. A precise evaluation of the primary ionization current (of about 5 pA) was performed. The absolute gain of the chambers was deduced as a function of the anode voltage and compared with the prediction of the Diethorn formula.

  13. A dual-chamber pacing mode to minimize ventricular pacing

    Directory of Open Access Journals (Sweden)

    Peter Rakovec

    2005-12-01

    Full Text Available Background: Though patients with sick sinus syndrome theoretically need an atrial pacemaker only, they usually receive a ventricular or a dual-chamber pacemaker because of possible developement of atrioventricular conduction abnormalities. Right ventricular pacing produces left bundle branch block (i.e. pacing-induced ventricular desynchronization, promoting heart failure and atrial fibrillation. This problem can be solved by a special pacing mode which on one hand preserves the safety of dual-chamber pacing and on the other hand minimizes right ventricular pacing.

  14. Precision Drift Chambers for the Atlas Muon Spectrometer

    CERN Document Server

    INSPIRE-00215825; Kortner, O.; Kroha, H.; Manz, A.; Mohrdieck, S.; Zhuravlov, V.

    2003-01-01

    ATLAS is a detector under construction to explore the physics at the Large Hadron Collider at CERN. It has a muon spectrometer with an excellent momentum resolution of 3-10%, provided by three layers of precision monitored-drift-tube chambers in a toroidal magnetic field. A single drift tube measures a track point with a mean resolution close to 100 micron, even at the expected high neutron and gamma background rates. The tubes are positioned within the chamber with an accuracy of 20 microns, achieved by elaborate construction and assembly monitoring procedures.

  15. Central tracking chamber with inflated cathode-strip foils

    Energy Technology Data Exchange (ETDEWEB)

    Blackmore, E.W.; Bryman, D.A.; Kuno, Y.; Lim, C.; Numao, T.; Padley, P.; Redlinger, G.; Soluk, R. [TRIUMF, Vancouver, BC (Canada); McPherson, R.A. [Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States)

    1998-02-21

    A new cylindrical low-mass central drift chamber has been constructed for the K{sup +}{yields}{pi}{sup +}{nu} anti {nu} experiment at BNL (E787). The chamber consists of twelve layers of axial wire cells and six layers of thin cathode-strip foils, four of which are supported by differential gas pressure. The momentum resolution (RMS) for muons and pions in the range 150-250 MeV/c is found to be about 0.9%. (orig.). 16 refs.

  16. Optical Pressure-Temperature Sensor for a Combustion Chamber

    Science.gov (United States)

    Wiley, John; Korman, Valentin; Gregory, Don

    2008-01-01

    A compact sensor for measuring temperature and pressure in a combusti on chamber has been proposed. The proposed sensor would include two optically birefringent, transmissive crystalline wedges: one of sapph ire (Al2O3) and one of magnesium oxide (MgO), the optical properties of both of which vary with temperature and pressure. The wedges wou ld be separated by a vapor-deposited thin-film transducer, which wou ld be primarily temperaturesensitive (in contradistinction to pressur e- sensitive) when attached to a crystalline substrate. The sensor w ould be housed in a rugged probe to survive the extreme temperatures and pressures in a combustion chamber.

  17. The User-friendly On-Line Diffusion Chamber

    CERN Document Server

    Aviles Acosta, Jaime

    2015-01-01

    The On-Line Diffusion Chamber is a stand-alone apparatus built to carry out short-live radiotracer diffusion studies. The availability of the on-demand production of isotopes in the ISOLDE facility, and the design of the apparatus to streamline the implantation process, annealing treatment, ion gun ablation with a tape transport system, and radiation intensity measurement with a Ge gamma detector all in the same apparatus, gives the On-Line Diffusion Chamber a unique ability to studies with short-lived radioisotopes or isomer states that are not possible in any other facility in the world.

  18. Cluster expansions for the correlated basis functions theory

    Energy Technology Data Exchange (ETDEWEB)

    Guardiola, R. (Granada Univ. (Spain). Dept. de Fisica Nuclear)

    1982-08-16

    Four kinds of cluster expansions for the calculation of non-diagonal matrix elements of the hamiltonian between correlated states have been derived. The derivation is based on a linearization mechanism for the standard cluster expansions in a configuration mixed state. Particulary simple formulae result for the multiplicative Factor-Aviles-Hartog-Tolhoek expansion and for the exponential form of the Gaudin-Gillespie-Ripka cluster expansion. The resulting expansions are directly usable in finite nuclei.

  19. Computational evaluation of a pencil ionization chamber in a standard diagnostic radiology beam

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, Dalila Souza Costa; Neves, Lucio Pereira; Perini, Ana Paula, E-mail: anapaula.perini@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica; Santos, William S.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Belinato, Walmir [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), Vitoria da Conquista, BA (Brazil)

    2016-07-01

    In this work a pencil ionization chamber was evaluated. This evaluation consisted in the determination of the influence of the ionization chamber components in its response. For this purpose, the Monte Carlo simulations and the spectrum of the standard diagnostic radiology beam (RQR5) were utilized. The results obtained, showed that the influence of the ionization chamber components presented no significant influence on the chamber response. Therefore, this ionization chamber is a good alternative for dosimetry in diagnostic radiology. (author)

  20. On Learning Ring-Sum-Expansions

    DEFF Research Database (Denmark)

    Fischer, Paul; Simon, H. -U.

    1992-01-01

    The problem of learning ring-sum-expansions from examples is studied. Ring-sum-expansions (RSE) are representations of Boolean functions over the base {#123;small infinum, (+), 1}#125;, which reflect arithmetic operations in GF(2). k-RSE is the class of ring-sum-expansions containing only monomials...... of length at most k:. term-RSE is the class of ring-sum-expansions having at most I: monomials. It is shown that k-RSE, k>or=1, is learnable while k-term-RSE, k>2, is not learnable if RPnot=NP. Without using a complexity-theoretical hypothesis, it is proven that k-RSE, k>or=1, and k-term-RSE, k>or=2 cannot...... be learned from positive (negative) examples alone. However, if the restriction that the hypothesis which is output by the learning algorithm is also a k-RSE is suspended, then k-RSE is learnable from positive (negative) examples only. Moreover, it is proved that 2-term-RSE is learnable by a conjunction...

  1. Negative thermal expansion in framework compounds

    Indian Academy of Sciences (India)

    electron microscopy, EXAFS and differential scanning calorimetry have been used to study structural properties as a function of temperature for these compounds. In this paper we report the results obtained from our study [14–20] of negative thermal expansion (NTE) compounds with chemical compositions of NX2O8 and.

  2. Polytope expansion of Lie characters and applications

    Energy Technology Data Exchange (ETDEWEB)

    Walton, Mark A., E-mail: walton@uleth.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta T1K 3M4 (Canada)

    2013-12-15

    The weight systems of finite-dimensional representations of complex, simple Lie algebras exhibit patterns beyond Weyl-group symmetry. These patterns occur because weight systems can be decomposed into lattice polytopes in a natural way. Since lattice polytopes are relatively simple, this decomposition is useful, in addition to being more economical than the decomposition into single weights. An expansion of characters into polytope sums follows from the polytope decomposition of weight systems. We study this polytope expansion here. A new, general formula is given for the polytope sums involved. The combinatorics of the polytope expansion are analyzed; we point out that they are reduced from those of the Weyl character formula (described by the Kostant partition function) in an optimal way. We also show that the weight multiplicities can be found easily from the polytope multiplicities, indicating explicitly the equivalence of the two descriptions. Finally, we demonstrate the utility of the polytope expansion by showing how polytope multiplicities can be used in the calculation of tensor product decompositions, and subalgebra branching rules.

  3. Resonant state expansion of the resolvent

    Energy Technology Data Exchange (ETDEWEB)

    Berggren, T.; Lind, P. (Department of Mathematical Physics, Lund Institute of Technology, P.O. Box 118, S-22100 Lund (Sweden))

    1993-02-01

    An analytic method of generating resonant state expansions from the standard completeness relation of nonrelativistic quantum mechanics is described and shown to reproduce the generalized completeness relations, earlier derived, involving resonant states. The method is then applied to the expansion of the resolvent (the complete Green's function), the symmetry properties of which [ital seem] to be destroyed if a conventional application of the completeness relations is made. These forms of expansions have a continuum term which contains symmetry-restoring contributions and can therefore never vanish identically, nor can it be neglected. The symmetry-conserving form of the expansion has a set of discrete terms which are identical in form to those of the Mittag-Leffler series for the resolvent. In addition, it contains a continuum contribution which in some cases vanishes identically, but in general does not. We illustrate these findings with numerical applictions in which the potential (a square well) is chosen so as to permit analytic evaluation of practically all functions and quantities involved.

  4. Annual cropped area expansion and agricultural production ...

    African Journals Online (AJOL)

    This paper assesses the relationship between annual cropped area expansion and crop output and discusses the implication of such a relationship for environmental management in Benue State, Nigeria. The study was carried out using agricultural production survey (APS) data of five selected crops, namely: rice, sorghum, ...

  5. Hole expansion test of third generation steels

    Science.gov (United States)

    Agirre, Julen; Mendiguren, Joseba; Galdos, Lander; de Argandoña, Eneko Sáenz

    2017-10-01

    The trend towards the implementation of new materials in the chassis of the automobiles is considerably making more complex the manufacturing of the components that built it up. In this scenario materials with higher strengths and lower formabilities are daily faced by tool makers and component producers what reduces the process windows and makes the forming processes to be in the limits of the materials. One of the concerns that tool makers must face during the definition of the tools is the expansion ratios that the holes in the sheet may reach before producing a breakage due to the stretching of the material (also known as edge cracks). For the characterization of such limits, a standard test, the hole expansion test, can be applied so that the limits of the material are known. At the present study, hole expansion tests of a third generation steel, Fortiform1050 with a thickness of 1.2 millimeters have been carried out and compared them to a mild steel, DX54D with a thickness of 0.6 millimeters. A comparison for each material in terms of technology used to punch the hole, mechanical punching vs laser cutting has also been conducted. In addition, the measurement technique (online measurement vs offline measurement) followed in the Hole Expansion Ratio (HER) identification has also been analyzed. Finally, differences between both materials and techniques are presented.

  6. The Asymptotic Expansion Method via Symbolic Computation

    Directory of Open Access Journals (Sweden)

    Juan F. Navarro

    2012-01-01

    Full Text Available This paper describes an algorithm for implementing a perturbation method based on an asymptotic expansion of the solution to a second-order differential equation. We also introduce a new symbolic computation system which works with the so-called modified quasipolynomials, as well as an implementation of the algorithm on it.

  7. Hydrodynamic Gradient Expansion in Gauge Theory Plasmas,

    NARCIS (Netherlands)

    Heller, M.P.; Janik, R.A.; Witaszczyk, P

    2013-01-01

    We utilize the fluid-gravity duality to investigate the large order behavior of hydrodynamic gradient expansion of the dynamics of a gauge theory plasma system. This corresponds to the inclusion of dissipative terms and transport coefficients of very high order. Using the dual gravity description,

  8. Expansion and contraction of finite states

    NARCIS (Netherlands)

    Tamminga, Allard

    2004-01-01

    We present a theory that copes with the dynamics of inconsistent information. A method is set forth to represent possibly inconsistent information by a *finite state*. Next, finite operations for expansion and contraction of finite states are given. No extra-logical element -- a choice function or

  9. A Computational Approach to Competitive Range Expansions

    Science.gov (United States)

    Weber, Markus F.; Poxleitner, Gabriele; Hebisch, Elke; Frey, Erwin; Opitz, Madeleine

    2014-03-01

    Bacterial communities represent complex and dynamic ecological systems. Environmental conditions and microbial interactions determine whether a bacterial strain survives an expansion to new territory. In our work, we studied competitive range expansions in a model system of three Escherichia coli strains. In this system, a colicin producing strain competed with a colicin resistant, and with a colicin sensitive strain for new territory. Genetic engineering allowed us to tune the strains' growth rates and to study their expansion in distinct ecological scenarios (with either cyclic or hierarchical dominance). The control over growth rates also enabled us to construct and to validate a predictive computational model of the bacterial dynamics. The model rested on an agent-based, coarse-grained description of the expansion process and we conducted independent experiments on the growth of single-strain colonies for its parametrization. Furthermore, the model considered the long-range nature of the toxin interaction between strains. The integration of experimental analysis with computational modeling made it possible to quantify how the level of biodiversity depends on the interplay between bacterial growth rates, the initial composition of the inoculum, and the toxin range.

  10. Effects of forest expansion on mountain grassland

    DEFF Research Database (Denmark)

    Guidi, Claudia; Magid, Jakob; Rodeghiero, Mirco

    2014-01-01

    Background and aims. Grassland abandonment followed by forest succession is the dominant land-use change in the European Alps. We studied the impact of current forest expansion on mountain grassland on changes in physical soil organic carbon (SOC) fractions along a land-use and management gradient...

  11. Stakeholder Support for School Food Policy Expansions

    Science.gov (United States)

    Pettigrew, Simone; Pescud, Melanie; Donovan, Robert J.

    2012-01-01

    The aim of this study was to assess the extent to which parents and school-based stakeholders (principals, teachers, canteen managers and Parents & Citizen Committee presidents) are supportive of potential expansions to a new school food policy. Eight additional policy components elicited in preliminary focus groups with parents and 19 additional…

  12. Global Expansion and English Language Learning

    Science.gov (United States)

    Andrade, Maureen Snow

    2016-01-01

    Demand for higher education is global. As institutions extend opportunities beyond their borders, English language proficiency must be considered. This chapter focuses on considerations related to global expansion, with an emphasis on the role of distance English language courses and the distinct considerations in their development.

  13. Taylor series expansions for stationary Markov chains

    NARCIS (Netherlands)

    Heidergott, B.F.; Hordijk, A.

    2003-01-01

    We study Taylor series expansions of stationary characteristics of general-state-space Markov chains. The elements of the Taylor series are explicitly calculated and a lower bound for the radius of convergence of the Taylor series is established. The analysis provided in this paper applies to the

  14. Term Dependence: Truncating the Bahadur Lazarsfeld Expansion.

    Science.gov (United States)

    Losee, Robert M., Jr.

    1994-01-01

    Studies the performance of probabilistic information retrieval systems using differing statistical dependence assumptions when estimating the probabilities inherent in the retrieval model. Experimental results using the Bahadur Lazarsfeld expansion on the Cystic Fibrosis database are discussed that suggest that incorporating term dependence…

  15. Revisting expansive learning for knowledge production and ...

    African Journals Online (AJOL)

    Revisting expansive learning for knowledge production and capability development at postgraduate level in Higher Education Studies. R Niemann. Abstract. Higher education in South Africa is challenged by academic and social demands. Universities, therefore, have to produce graduates who will be able to function ...

  16. On the Convergence of the Virial Expansion

    NARCIS (Netherlands)

    Ramawadh, S.D.

    2015-01-01

    The virial expansion appears in statistical mechanics, an area where physics and mathematics intersect. Throughout this thesis we will mostly ignore the physics and mainly focus on the mathematical aspects. This is a deliberate choice, made for two reasons. Firstly, there are several books that

  17. Critical point anomalies include expansion shock waves

    NARCIS (Netherlands)

    Nannen, N.R.; Guardone, A.; Colonna, P.

    2014-01-01

    From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the

  18. The replication of expansive production knowledge

    DEFF Research Database (Denmark)

    Wæhrens, Brian Vejrum; Yang, Cheng; Madsen, Erik Skov

    2012-01-01

    Purpose – With the aim to support offshore production line replication, this paper specifically aims to explore the use of templates and principles to transfer expansive productive knowledge embedded in a production line and understand the contingencies that influence the mix of these approaches....

  19. Expansion patterns and parallaxes for planetary nebulae

    Science.gov (United States)

    Schönberner, D.; Balick, B.; Jacob, R.

    2018-02-01

    Aims: We aim to determine individual distances to a small number of rather round, quite regularly shaped planetary nebulae by combining their angular expansion in the plane of the sky with a spectroscopically measured expansion along the line of sight. Methods: We combined up to three epochs of Hubble Space Telescope imaging data and determined the angular proper motions of rim and shell edges and of other features. These results are combined with measured expansion speeds to determine individual distances by assuming that line of sight and sky-plane expansions are equal. We employed 1D radiation-hydrodynamics simulations of nebular evolution to correct for the difference between the spectroscopically measured expansion velocities of rim and shell and of their respective shock fronts. Results: Rim and shell are two independently expanding entities, driven by different physical mechanisms, although their model-based expansion timescales are quite similar. We derive good individual distances for 15 objects, and the main results are as follows: (i) distances derived from rim and shell agree well; (ii) comparison with the statistical distances in the literature gives reasonable agreement; (iii) our distances disagree with those derived by spectroscopic methods; (iv) central-star "plateau" luminosities range from about 2000 L⊙ to well below 10 000 L⊙, with a mean value at about 5000 L⊙, in excellent agreement with other samples of known distance (Galactic bulge, Magellanic Clouds, and K648 in the globular cluster M 15); (v) the central-star mass range is rather restricted: from about 0.53 to about 0.56 M⊙, with a mean value of 0.55 M⊙. Conclusions: The expansion measurements of nebular rim and shell edges confirm the predictions of radiation-hydrodynamics simulations and offer a reliable method for the evaluation of distances to suited objects. Results of this paper are based on observations made with the NASA/ESA Hubble Space Telescope in Cycle 16 (GO11122

  20. 216-B-3 expansion ponds closure plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA.