WorldWideScience

Sample records for spark chamber photographs

  1. Optical spark chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    An optical spark chamber developed for use in the Omega spectrometer. On the left the supporting frame is exceptionally thin to allow low momentum particles to escape and be detected outside the magnetic field.

  2. The analysis of track chamber photographs using flying spot digitizers

    CERN Multimedia

    Powell, Brian W

    1966-01-01

    A vast quantity of data pours from the experiments on particle accelerators throughout the world. For example, over 300 000 photographs per week came from the three bubble chambers operating on the CERN PS at the end of 1965. The conventional method of processing these bubble chamber photographs is for each one of them to be examined ('scanned') to see whether it records an interesting particle interaction. The interesting photographs are then passed to hand operated measuring machines to obtain precise measurements of the particle trajectories recorded on the film. Similar measurements are carried out on photographs taken in film spark chamber experiments. This article on the Flying Spot Digitizers at CERN describes one of the most fruitful attempts to speed and make more accurate the process of analysis of bubble and spark chamber photographs. There are two types of Flying Spot Digitizer at CERN — the HPD or Hough Powell Device (named after Professor Hough and the author who, together, initiated the devel...

  3. Detector for recoil nuclei stopping in the spark chamber gas

    International Nuclear Information System (INIS)

    Aleksanyan, A.S.; Asatiani, T.L.; Ivanov, V.I.; Mkrtchyan, G.G.; Pikhtelev, R.N.

    1974-01-01

    A detector consisting of the combination of a drift and a wide gap spark chambers and designed to detect recoil nuclei stopping in the spark chamber gas is described. It is shown, that by using an appropriate discrimination the detector allows to detect reliably the recoil nuclei in the presence of intensive electron and γ-quanta beams

  4. Track photographing in 8-m streamer chamber

    International Nuclear Information System (INIS)

    Anisimova, N.Z.; Davidenko, V.A.; Kantserov, V.A.; Rybakov, V.G.; Somov, S.V.

    1981-01-01

    A system for obtaining data from a streamer chamber intended for measuring muon polarization is described. An optical scheme for photographing of tracks in the chamber is given. The photographing process is complicated at the expense of large dimensions and module structure of the chamber as well as due to insufficient for direct photographing brightness of streamers. The system described was tested during a long time in a physical experiment. More than 100 thousand photos have been taken by its means [ru

  5. Radiofrequency spark chambers and delay line resonators

    International Nuclear Information System (INIS)

    Sayag, Jacques

    1971-01-01

    According to a suggestion of A. Kastler, a spark chamber was excited by an undamped radiofrequency pulse and tracks about 1 mm wide obtained; the result was interpreted by computation of the coefficients of electronic amplification and partial ambipolar diffusion. This work led us to the construction of a new fast triggering undamped wave-train generator of very high tension (patent taken out by the C.E.A. under the no.: EN 7 134 650 the 27.9.1971). Since this apparatus uses a resonant storage line, its design implied a precise knowledge of high impedance delay lines. The experimental radiofrequency spectra of the input impedance of opened or short-circuited lines were plotted completely and analysed by the circuits theory, new measuring methods were established, dispersion relations accurately checked and the equivalence of the formulas, within the third order, with theses of Debye's Dipolar Absorption demonstrated. General properties of Hilbert's transform were also investigated. From the experimental point of view, the electromagnetic energy storage process was extended to the case of a liquid nitrogen-immersed resonant delay line. The good behavior of the cryogenic experiment, where the main difficulty of icing was overcame by the construction of special electrodes, offers great promise for extrapolation to superconductivity. (author) [fr

  6. 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

  7. Spark chamber used for the visualization of the 125I labeled thyroid

    International Nuclear Information System (INIS)

    Morucci, Jean-Pierre; Seigneur, Alain; Lansiart, Alain

    1971-03-01

    This spark chamber is a stationary detector used for the visualization of the 125 I labeled thyroid; it is sensitive to X and low energy gamma rays. This device is filled mainly with pressurized xenon (1.5 kg/cm 2 ) and behaves as an X-ray image intensifier: the incident radiation is detected and initiates a spark. The energy dissipated by the spark is reduced and controlled by a double coated anode, while an electronic circuit triggered by the initiation of the spark discharges the detector capacitance. The sparks are recorded on a photographic plate during the examination. X ray optics are used for collimation between the thyroid and the detector. A modulation transfer function was measured for 125 I. Communication theory was used to determine the best way of combining the collimator and spark chamber. This device is being used in the Service Hospitalier Frederic Joliot at Orsay. Its performance is superior to that of conventional scintigraphs. Further applications are envisaged [fr

  8. Stopping particles in the Mont Blanc spark chamber telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Bergamasco, L; Bilokon, H; Piazzoli, B E; Mannocchi, G; Picchi, P [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale)

    1982-02-01

    We present the final results on the ratio of stopping to traversing muons as measured by two spark chamber telescopes in the Mont Blanc Station, Italy, at 4300 hg/cm/sup 2/. The experimental results are in agreement with the theoretical values within the limits of the error.

  9. A study of the air-shower response of current-limited spark chambers

    International Nuclear Information System (INIS)

    Porter, M.R.; Hodson, A.L.; Bull, R.M.

    1982-01-01

    The efficiency of current-limited spark chambers (discharge chambers) and their relative response to shower electrons and photons are investigated. A stack of six horizontal 1m x 10 cm discharge chambers, above one another, is triggered by air showers falling on an adjacent discharge-chamber array. Particular combinations of discharges show that the efficiency of the chambers is very high and that a significant fraction of the discharges is due to incident photons

  10. An image scanner for real time analysis of spark chamber images

    International Nuclear Information System (INIS)

    Cesaroni, F.; Penso, G.; Locci, A.M.; Spano, M.A.

    1975-01-01

    The notes describes the semiautomatic scanning system at LNF for the analysis of spark chamber images. From the projection of the images on the scanner table, the trajectory in the real space is reconstructed

  11. A 4π scintillation counter-optical spark chamber system for neutral particles

    International Nuclear Information System (INIS)

    Demarzo, C.; Distante, A.; Guerriero, L.; Niccolini, C.; Posa, F.; Walder, F.; Chen, G.T.Y.; Fletcher, C.R.; Lanou, R.E. Jr.; Thornton, R.K.; Barton, D.S.; Lyons, T.; Marx, M.; Rosenson, L.; Thern, R.

    1975-01-01

    The authors describe a scintillation counter-optical spark chamber system developed for the detection of high energy gamma rays and neutrons. They describe the system components and their use in two completed experiments. (Auth.)

  12. The performance of a hybrid spark chamber beta-ray camera

    International Nuclear Information System (INIS)

    Aoyama, Takahiko; Watanabe, Tamaki

    1978-01-01

    This paper describes the performance of a hybrid spark chamber for measuring β-ray emitting radionuclide distribution on a plane source, which was developed to improve the instability of usual self-triggering spark chambers. The chamber consists of a parallel plate spark chamber gap and a parallel plate proportional chamber gap composed of mesh electrodes in the same gas space, and is operated by flowing gas, a mixture of argon and ethanol saturated vapor at 0 0 C, continuously through it. Instability is due to the occurrence of spurious sparks not caused by incident particles and it became conspicuous in the small intensity of incident particles. The hybrid spark chamber enabled us to obtain good counting plateau, that is, good stability for especially small intensity of β-rays and even for the background by setting up gas multiplication in the proportional chamber gap moderately high. Good spatial resolution less than 1 mm was obtained for 3 H and 14 C by keeping the distance between the chamber cathode and the source less than 1 mm. In order to obtain good spatial resolution, it is desirable to keep the overvoltage as small as possible while small overvoltage results in the deterioration of the uniformity of sensitivity. It was found by theoretical estimation and experiment that for a given large overvoltage the spatial resolution was improved by increasing the gas multiplication in the proportional chamber gap. The hybrid spark chamber has a relatively long dead time. When there being a number of active spots having different activities in a detection area, the sparking efficiency of a weak active spot also decreases by large counting loss due to the total strong activity. (auth.)

  13. Simulation of muon transport through the aragats spark chamber calorimeter

    International Nuclear Information System (INIS)

    Asatiani, T.L.; Ter-Antonyan, S.V.

    1981-01-01

    The algorithm is presented of the program on simulation of muon transport through Aragats spark calorimeter. Statistic test method with account of fluctuations and angular distributions of cascade showers is used. The program is worked out on the Fortran algorithm language for EVM BESM-6 and is calibrated by experimental data of Aragats complex installation [ru

  14. Reconstruction of data for an experiment using multi-gap spark chambers with six-camera optics

    International Nuclear Information System (INIS)

    Maybury, R.; Daley, H.M.

    1983-06-01

    A program has been developed to reconstruct spark positions in a pair of multi-gap optical spark chambers viewed by six cameras, which were used by a Rutherford Laboratory experiment. The procedure for correlating camera views to calculate spark positions is described. Calibration of the apparatus, and the application of time- and intensity-dependent corrections are discussed. (author)

  15. Development of the discharge (spark) chamber in Japan in the 1950s

    International Nuclear Information System (INIS)

    Fukui, Shuji

    1989-01-01

    The paper, written by its Japanese inventor Shuji Fukui, describes the development of the discharge or spark chamber in Japan in the 1950s. Flash-tubes were used in air-shower cosmic-ray experiments and this led to his design of a neon hodoscope detector. By including the property of neon bulbs glowing the discharge chamber was born, after he observed localized discharges along the trajectories of cosmic-ray particles. (UK)

  16. Measurement of the spark probability in single gap parallel plate chambers

    International Nuclear Information System (INIS)

    Arefiev, A.; Bencze, Gy.L.; Choumilov, E.; Civinini, C.; Dalla Santa, F.; D'Alessandro, R.; Ferrando, A.; Fouz, M.C.; Golovkin, V.; Kholodenko, A.; Iglesias, A.; Ivochkin, V.; Josa, M.I.; Malinin, A.; Meschini, M.; Misyura, S.; Pojidaev, V.; Salicio, J.M.

    1996-01-01

    We present results on the measurements of the spark probability with CO 2 and CF 4 /CO 2 (80/20) mixture, at atmospheric pressure, using 1.5 mm gas gap parallel plate chambers, working at a gas gain ranging from 4.5 x 10 2 to 3.3 x 10 4 . (orig.)

  17. A Photographic Study of Combustion and Knock in a Spark-Ignition Engine

    Science.gov (United States)

    Rothrock, A M; Spencer, R C

    1938-01-01

    Report presents the results of a photographic study of the combustion in a spark-ignition engine using both Schlieren and flame photographs taken at high rates of speed. Although shock waves are present after knock occurs, there was no evidence of any type of sonic or supersonic compression waves existing in the combustion gases prior to the occurrence of knock. Artificially induced shock waves in the engine did not in themselves cause knock. The photographs also indicate that, although auto-ignition ahead of the flame front may occur in conjunction with knock, it is not necessary for the occurrence of knock. There is also evidence that the reaction is not completed in the flame front but continues for some time after the flame front has passed through the charge.

  18. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber

    KAUST Repository

    Wolk, Benjamin

    2013-07-01

    The enhancement of laminar flame development using microwave-assisted spark ignition has been investigated for methane-air mixtures at a range of initial pressures and equivalence ratios in a 1.45. l constant volume combustion chamber. Microwave enhancement was evaluated on the basis of several parameters including flame development time (FDT) (time for 0-10% of total net heat release), flame rise time (FRT) (time for 10-90% of total net heat release), total net heat release, flame kernel growth rate, flame kernel size, and ignitability limit extension. Compared to a capacitive discharge spark, microwave-assisted spark ignition extended the lean and rich ignition limits at all pressures investigated (1.08-7.22. bar). The addition of microwaves to a capacitive discharge spark reduced FDT and increased the flame kernel size for all equivalence ratios tested and resulted in increases in the spatial flame speed for sufficiently lean flames. Flame enhancement is believed to be caused by (1) a non-thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure of the mixture increases, with negligible flame enhancement observed above 3. bar. © 2013 The Combustion Institute.

  19. Photographic emulsion versus bubble chambers in charm and beauty searches

    International Nuclear Information System (INIS)

    Sacton, J.

    1984-01-01

    This chapter discusses the use of visual detectors in the search for charm and other flavors. The photographic emulsion and the bubble chamber techniques are compared. The main difficulties encounted in searching for charmed and beautiful hadrons are related to the short lifetimes of these particles and to their small production cross-sections, even at SPS energies. Resolution, visibility, the data analysis rate, and exposure time are considered. Most of the charmed hadrons present a large variety of decay modes of which only a fraction has been identified to date. First results from CESR indicate that the average charged particle multiplicity in the hadronic decay of beautiful hadrons is as high as 6.31 + or - 0.35; no B meson decay has yet been kinematically reconstructed. The case of hadronic charmed particle production at SPS energies is examined. The data show that 1) the bubble chamber technique (high resolution or holographic optics) is well suited to the study of charmed hadrons with lifetimes in the range 10 -13 to 10 -12 s; 2) searches for beautiful hadrons remain presently a domain for triggered emulsion experiments due to the smallness of the production cross-sections (provided the lifetime is not much shorter than 10 -14 s); and 3) for particles of lifetimes shorter than a few times 10 -14 s the emulsion technique is still without competitor

  20. Improving the performance and fuel consumption of dual chamber stratified charge spark ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Sorenson, S.C.; Pan, S.S.; Bruckbauer, J.J.; Gehrke, G.R.

    1979-09-01

    A combined experimental and theoretical investigation of the nature of the combustion processes in a dual chamber stratified charge spark ignition engine is described. This work concentrated on understanding the mixing process in the main chamber gases. A specially constructed single cylinder engine was used to both conduct experiments to study mixing effects and to obtain experimental data for the validation of the computer model which was constructed in the theoretical portion of the study. The test procedures are described. Studies were conducted on the effect of fuel injection timing on performance and emissions using the combination of orifice size and prechamber to main chamber flow rate ratio which gave the best overall compromise between emissions and performance. In general, fuel injection gave slightly higher oxides of nitrogen, but considerably lower hydrocarbon and carbon monoxide emissions than the carbureted form of the engine. Experiments with engine intake port redesign to promote swirl mixing indicated a substantial increase in the power output from the engine and, that an equivalent power levels, the nitric oxide emissions are approximately 30% lower with swirl in the main chamber than without swirl. The development of a computer simulation of the combustion process showed that a one-dimensional combustion model can be used to accurately predict trends in engine operation conditions and nitric oxide emissions even though the actual flame in the engine is not completely one-dimensional, and that a simple model for mixing of the main chamber and prechamber intake gases at the start of compression proved adequate to explain the effects of swirl, ignition timing, overall fuel air ratio, volumetric efficiency, and variations in prechamber air fuel ratio and fuel rate percentage on engine power and nitric oxide emissions. (LCL)

  1. Automatisation of reading and interpreting photographically recorded spark source mass spectra for the quantitative analysis in solids

    International Nuclear Information System (INIS)

    Naudin, Guy.

    1976-01-01

    Quantitative analysis in solids by spark source mass spectrometry involves the study of photographic plates by means of a microdensitometer. After a graphic treatment of data from the plate, a scientific program is used to calculate the concentrations of isotopes. The automatisation of the three parts has been realised by using a program for computer. This program has been written in the laboratory for a small computer (Multi 8, Intertechnique) [fr

  2. Gamma radiation measurement, through a spark chamber put aboard of a stratospheric balloon

    International Nuclear Information System (INIS)

    Santo, C.M.E.; Rao, K.R.

    1982-06-01

    For determining the diffuse component of gamma rays in the 15 to 75 Mev range arriving from near the galactic center, a digitized spark chamber was launched aboard two balloons from Resende, Brazil, on 19 November and 3 December 1975. In each flight the detector reached an altitude of 2,2 g/cm 2 . Based on these data, a diffuse gamma ray flux 6,0x10 - 5 , 2,0x10 - 5 , 4,6x10 - 6 and 1,3x10 - 6 photons (cm 2 .s.sterad.Mev) at energies of 21, 36, 52, 67 Mev respectively was obtained. These values give a power law spectrum with spectral index equal to -3,3. The dependence of this radiation with the galactic latitude and longitude in the interval -5 0 0 and 325 0 0 was also obtained. Finally, our results were compared with other experiments' results. (Author) [pt

  3. Reversal film development for streamer chamber track photographs

    International Nuclear Information System (INIS)

    Bahr, J.

    1982-01-01

    It is the aim of this work to create a method of photographic development specially adapted to streamer image recording, i.e., with high sensitivity, only two signal levels, low dependence of the track signal on image intensity having a great jitter and noise suppression. The method has to be suitable for machine development of high speed films. A reversal photographic development was used to realize these demands, whereby strong fogging in the first step negative development and a solving process for silver bromide after blackening are specially introduced process stages. This results in a step-function shaped characteristic curve with small transition region having only two signal levels, i. e., independence of streamer image density, good resolution, fine grain, suppression of flares and low noise in the signal of the clear streamer images

  4. Quasi-dimensional modeling of a fast-burn combustion dual-plug spark-ignition engine with complex combustion chamber geometries

    International Nuclear Information System (INIS)

    Altın, İsmail; Bilgin, Atilla

    2015-01-01

    This study builds on a previous parametric investigation using a thermodynamic-based quasi-dimensional (QD) cycle simulation of a spark-ignition (SI) engine with dual-spark plugs. The previous work examined the effects of plug-number and location on some performance parameters considering an engine with a simple cylindrical disc-shaped combustion chamber. In order to provide QD thermodynamic models applicable to complex combustion chamber geometries, a novel approach is considered here: flame-maps, which utilizes a computer aided design (CAD) software (SolidWorks). Flame maps are produced by the CAD software, which comprise all the possible flame radiuses with an increment of one-mm between them, according to the spark plug positions, spark timing, and piston position near the top dead center. The data are tabulated and stored as matrices. Then, these tabulated data are adapted to the previously reported cycle simulation. After testing for simple disc-shaped chamber geometries, the simulation is applied to a real production automobile (Honda-Fit) engine to perform the parametric study. - Highlights: • QD model was applied in dual plug engine with complex realistic combustion chamber. • This method successfully modeled the combustion in the dual-plug Honda-Fit engine. • The same combustion chamber is tested for various spark plug(s) locations. • The centrally located single spark-plug results in the fastest combustion

  5. Large area spark chamber and support, and method of recording and analyzing the information on a radioactive work piece

    International Nuclear Information System (INIS)

    Britten, R.J.; Davidson, E.H.

    1985-01-01

    Novel large area spark chamber having a support for carrying a generally planar, radioactive work piece. The spark chamber has a thin window which is either a rigid plastic sheet carrying a thin layer of an electrically conductive material on the surface thereof, or a thin planar piece or film of electrically conductive metal. There is positioned in superposed relationship to the thin window, a layer of semi-conducting glass in spaced-apart relationship from the thin window by a resilient insulating seal to form an enclosed gas retaining chamber. An electrically conducting surface is adhered to the upper surface of the layer of semi-conducting glass. An electrically conductive path is provided between the thin layer of electrically conductive material on the thin window and the electrically conducting surface on said semi-conducting glass. The electrically conductive path includes a high voltage supply and TDCs and ADCs. There are also means for detecting the location of sites of impingement of radiation on the electrically conducting surface of the semi-conducting glass, and means for recording and analyzing the information present on the work piece

  6. A programming system for bubble chamber photographs measuring tables on-line to a computer

    International Nuclear Information System (INIS)

    Miche, Roger.

    1975-06-01

    A programming system available on an industrial computer, type PDP 15/20, performing the exploitation of bubble chamber pictures with the projection tables on line to the computer was developed. This system must suit the particular conditions met in the analysis of photographs from different bubble chambers, the different stage for dealing with the views (scanning, premeasurement, measurement) adapting to different strategies in the handling of measurements. The exploitation of photographs takes place in a conversational mode to which a concrete form is given by sending messages to the operators at the tables and by receiving coded answers. In this framework, the aims of the operating system are: to guide the operator work at the tables while allowing them to interrupt the normal sequence of events, to carry out some elementary logical checks, to write on magnetic tape the checked data with the appropriate labels as required [fr

  7. Possibilities to improve sensitivity and rendering of detail of streamer chamber track photographs

    Energy Technology Data Exchange (ETDEWEB)

    Baehr, J

    1975-01-01

    Streamer chambers are increasingly used as effective particle detectors in the field of experimental elementary particle physics. The photographic recording of high energy events in streamer chambers is limited by performance of current photographic silver-halide layers. Similar limiting problems occur in other fields as well, e.g., in astronomy, x-ray medicine and photogrammetry; therefore methods have been developed to increase sensitivity and improve the information transfer of the emulsion. In this paper these methods have been classified and summarized under the aspect of their application to streamer image recording. Proposals for further investigations are given. Especially the applicability of these methods, their possibility of combination to large film lengths should be investigated The detective quantum efficiency (DQE) is proposed as criterion to estimate and compare the different methods.

  8. Search of significant features in a direct non parametric pattern recognition method. Application to the classification of a multiwire spark chamber picture

    International Nuclear Information System (INIS)

    Buccheri, R.; Coffaro, P.; Di Gesu, V.; Salemi, S.; Colomba, G.

    1975-01-01

    Preliminary results are given of the application of a direct non parametric pattern recognition method to the classification of the pictures of a multiwire spark chamber. The method, developed in an earlier work for an optical spark chamber, looks promising. The picture sample used has with respect to the previous one, the following characteristis: a) the event pictures have a more complicated structure; b) the amount of background sparks in an event is greater; c) there exists a kind of noise which is almost always present in some structured way (double sparkling, bursts...). New features have been used to characterize the event pictures; the results show that the method could be also used as a super filter to reduce the cost of further analysis. (Auth.)

  9. Spark Channels

    Energy Technology Data Exchange (ETDEWEB)

    Haydon, S. C. [Department of Physics, University of New England, Armidale, NSW (Australia)

    1968-04-15

    A brief summary is given of the principal methods used for initiating spark channels and the various highly time-resolved techniques developed recently for studies with nanosecond resolution. The importance of the percentage overvoltage in determining the early history and subsequent development of the various phases of the growth of the spark channel is discussed. An account is then given of the recent photographic, oscillographic and spectroscopic investigations of spark channels initiated by co-axial cable discharges of spark gaps at low [{approx} 1%] overvoltages. The phenomena observed in the development of the immediate post-breakdown phase, the diffuse glow structure, the growth of the luminous filament and the final formation of the spark channel in hydrogen are described. A brief account is also given of the salient features emerging from corresponding studies of highly overvolted spark gaps in which the spark channel develops from single avalanche conditions. The essential differences between the two types of channel formation are summarized and possible explanations of the general features are indicated. (author)

  10. Giuseppe and Maria Fidecaro inside the spark chamber apparatus in the South Hall of PS to search for the $\\rho \\rightarrow \\pi\\gamma$ decay

    CERN Multimedia

    Gérard Bertin; CERN PhotoLab

    1964-01-01

    The lens, the so-called front view (see album https://cds.cern.ch/record/1974123), was used in the S30 experiment to converge onto a camera parallel light rays from the front of a large spark chamber. A second identical lens, the so-called top view, and a large mirror were used to take pictures at 90 degrees in such a way to determine the x,y coordinates in the horizontal plane of each spark. Details of the optics are reported in the note: A $\\gamma$-ray detector for the study of the electromagnetic decay of resonances, INFN/AE - 67/7, 20 Jun 1967, by F. Bradamante, G. Fidecaro, M. Fidecaro, M. Giorgi, F. Sauli, P. Schiavon.

  11. Data-processing system for bubble-chamber photographs based on PUOS-4 measuring projectors and an ES-1045 computer

    International Nuclear Information System (INIS)

    Ermolov, P.F.; Kozlov, V.V.; Rukovichkin, V.P.

    1988-01-01

    A system is described that was developed at the Scientific-Research Institute of Nuclear Physics for processing of the data recorded on stereoscopic photographs from large bubble chambers and hybrid spectrometers using PUOS-4 measuring projectors, an Elektronika-60 microcomputer, and an ES-1045 computer. The system structure, the main programmable interfaces, and the intercomputer communications are examined. The mean-square error of the measuring channels of the system, determined from calibration measurements, is within 1.3-3.5 μm; the standard deviation of the coordinates of the measured points with respect to the track in the plane of the photograph is 6 μm. The system is widely used at the institute for analysis of data from experiments in high-energy physics performed with the European Hybrid Spectrometer and the Mirabel large bubble chamber. Approximately 80,000 stereoscopic photographs have been processed and the system is being prepared to process data from the Skat bubble chamber and a spectrometer with a vertex detector that is under construction

  12. Automatic scanning of Cerenkov light photograms from a multistep avalanche chamber using a television digitizer

    International Nuclear Information System (INIS)

    Vascon, M.; Zanella, G.

    1980-01-01

    A television digitizer and its application to automatic scanning of Cerenkov imaging using the multistep avalanche chamber in front of optical spark chamber are described. The results are of interest in the adoption of the automatic scanning of photographic plates of these events or for the on-line application of the television digitizer itself. (orig.)

  13. Bubbles, sparks, and the postwar laboratory

    International Nuclear Information System (INIS)

    Galison, P.

    1989-01-01

    The development and use of bubble chambers and spark chambers in the 1950s form the main thrust of this article, the bubble chamber as an example of ''image-producing'' instruments and the spark chamber as a ''logic'' device. Work on a cloud chamber by Glaser led to the development of the bubble chamber detector using liquid hydrogen, which was later linked to a computer for accurate automatic track analysis. It made possible demonstrations of the existence of a particle or interaction. Spark chambers were easier to build and so soon became common, various types being developed across the world. The development of spark chambers originated in the need for timing devices for the Manhattan Project, but work on their design occurred in a number of units worldwide. (UK)

  14. HOLRED - a machine to reproduce and photograph real images from holograms taken in the 15 foot bubble chamber at Fermilab

    International Nuclear Information System (INIS)

    Nailor, P.R.

    1985-01-01

    The aim of this paper is to describe the design criteria and philosophy behind a machine to reproject and photograph the real images of neutrino interactions from holograms taken there in the coming run. Detailed analysis of the vertex region of these events will be done from the photographs. (orig./HSI)

  15. Around the laboratories: Dubna: Physics results and progress on bubble chamber techniques; Stanford (SLAC): Operation of a very rapid cycling bubble chamber; Daresbury: Photographs of visitors to the Laboratory; Argonne: Charge exchange injection tests into the ZGS in preparation for a proposed Booster

    CERN Multimedia

    1969-01-01

    Around the laboratories: Dubna: Physics results and progress on bubble chamber techniques; Stanford (SLAC): Operation of a very rapid cycling bubble chamber; Daresbury: Photographs of visitors to the Laboratory; Argonne: Charge exchange injection tests into the ZGS in preparation for a proposed Booster

  16. Efficiency calibration of solid track spark auto counter

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Liu Rong; Jiang Li; Lu Xinxin; Zhu Tonghua

    2008-01-01

    The factors influencing detection efficiency of solid track spark auto counter were analyzed, and the best etch condition and parameters of charge were also reconfirmed. With small plate fission ionization chamber, the efficiency of solid track spark auto counter at various experiment assemblies was re-calibrated. The efficiency of solid track spark auto counter at various experimental conditions was obtained. (authors)

  17. Specific features of a single-pulse sliding discharge in neon near the threshold for spark breakdown

    Science.gov (United States)

    Trusov, K. K.

    2017-08-01

    Experimental data on the spatial structure of a single-pulse sliding discharge in neon at voltages below, equal to, and above the threshold for spark breakdown are discussed. The experiments were carried at gas pressures of 30 and 100 kPa and different polarities of the discharge voltage. Photographs of the plasma structure in two discharge chambers with different dimensions of the discharge zone and different thicknesses of an alumina dielectric plate on the surface of which the discharge develops are inspected. Common features of the prebreakdown discharge and its specific features depending on the voltage polarity and gas pressure are analyzed. It is shown that, at voltages below the threshold for spark breakdown, a low-current glow discharge with cathode and anode spots develops in the electrode gap. Above the breakdown threshold, regardless of the voltage polarity, spark channels directed from the cathode to the anode develop against the background of a low-current discharge.

  18. The suppression of destructive sparks in parallel plate proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Cockshott, R.A.; Mason, I.M.

    1984-02-01

    The authors find that high energy background events produce localised sparks in parallel plate counters when operated in the proportional mode. These sparks increase dead-time and lead to degradation ranging from electrode damage to spurious pulsing and continuous breakdown. The problem is particularly serious in low energy photon detectors for X-ray astronomy which are required to have lifetimes of several years in the high radiation environment of space. For the parallel plate imaging detector developed for the European X-ray Observatory Satellite (EXOSAT) they investigate quantitatively the spark thresholds, spark rates and degradation processes. They discuss the spark mechanism, pointing out differences from the situation in spark chambers and counters. They show that the time profile of the sparks allows them to devise a spark suppression system which reduces the degradation rate by a factor of ''200.

  19. Evaluation of white-to-white distance and anterior chamber depth measurements using the IOL Master, slit-lamp adapted optical coherence tomography and digital photographs in phakic eyes.

    Science.gov (United States)

    Wilczyński, Michał; Pośpiech-Zabierek, Aleksandra

    2015-01-01

    The accurate measurement of the anterior chamber internal diameter and depth is important in ophthalmic diagnosis and before some eye surgery procedures. The purpose of the study was to compare the white-to-white distance measurements performed using the IOL-Master and photography with internal anterior chamber diameter determined using slit lamp adapted optical coherence tomography in healthy eyes, and to compare anterior chamber depth measurements by IOL-Master and slit lamp adapted optical coherence tomography. The data were gathered prospectively from a non-randomized consecutive series of patients. The examined group consisted of 46 eyes of 39 patients. White-to-white was measured using IOL-Master and photographs of the eye were taken with a digital camera. Internal anterior chamber diameter was measured with slit-lamp adapted optical coherence tomography. Anterior chamber depth was measured using the IOL Master and slit-lamp adapted optical coherence tomography. Statistical analysis was performed using parametric tests. A Bland-Altman plot was drawn. White-to-white distance by the IOL Master was 11.8 +/- 0.40 mm, on photographs it was 11.29 +/- 0.58 mm and internal anterior chamber diameter by slit-lamp adapted optical coherence tomography was 11.34?0.54 mm. A significant difference was found between IOL-Master and slit-lamp adapted optical coherence tomography (pphotographs (pphotographs (p>0.05). All measurements were correlated (Spearman pphotographs. In order to obtain accurate measurements of the internal anterior chamber diameter and anterior chamber depth, a method involving direct visualization of intraocular structures should be used.

  20. 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.

  1. Laser spark distribution and ignition system

    Science.gov (United States)

    Woodruff, Steven [Morgantown, WV; McIntyre, Dustin L [Morgantown, WV

    2008-09-02

    A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

  2. Display of a proton-proton interaction as seen in the streamer chamber of NA5

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    This experiment was performed by the Bari-Cracow-Liverpool-Munich (MPI)-Nijmegen Collaboration using the unseparated H2 beam in the EHN1 hall. The setup consisted of a three-gap streamer chamber (2x1.4x0.72 m3) inside a superconducting vertex magnet, large magnetostrictive spark chambers, proportional chambers and beam defining counters. A large acceptance electron and hadron calorimeter completed the setup. Particles from beam interactions on a target, 36.5 cm long, 2 cm in diameter (for liquid hydrogen) located inside the chamber at its entrance were photographed. Multiplicities, rapidity distributions, and correlations were studied for interactions with a large value for the sum of the transverse momenta.

  3. An experimental investigation of a lean-burn natural-gas pre-chamber spark ignition engine for cogeneration; Swiss Motor. Modification d'un moteur diesel pour le fonctionnement au gaz naturel en cogeneration. Fonctionnement avec prechambre de combustion

    Energy Technology Data Exchange (ETDEWEB)

    Roethlisberger, R.; Favrat, D.

    2001-07-01

    This thesis presented at the Department of Mechanical Engineering of the Swiss Federal Institute of Technology in Lausanne describes the conversion and testing of a commercial diesel engine for use as a lean-burn, natural gas, pre-chamber, spark ignition engine with a rated power of 150 kW, in combined heat and power (CHP) plants. The objective of the investigations - to evaluate the potential of reducing exhaust gas emissions - is discussed in detail with respect to NO{sub x} and CO emissions. The approach adopted includes both experimental work and numerical simulation. The report describes the testing facilities used. The results obtained with experimental spark-plug configurations based on simulation results are presented and the influence of various pre-chamber configuration variants are discussed. The results of the tests are presented and the significant reduction of NO{sub x}, CO and unburned-hydrocarbon (THC) emissions are discussed. The authors state that the engine, which achieves a fuel efficiency of more than 36.5%, fulfils the Swiss requirements on exhaust gas emissions. Also, ways of compensating for the slight loss in fuel-conversion efficiency in the pre-chamber configuration are discussed.

  4. Reconstruction of data in low-mass magnetostrictive chambers

    International Nuclear Information System (INIS)

    Daley, H.M.

    1983-01-01

    The reconstruction of spark positions in a set of low-mass spark chambers with remote magnetostrictive readout, used in a study of the reaction π - p → K 0 Λ, is described. The main detectors used were optical spark chambers but in order to provide information close to the vertices low-mass magnetostrictive chambers were fitted inside the cone of the superconducting polarised target magnet. (U.K.)

  5. Fastdata processing with Spark

    CERN Document Server

    Karau, Holden

    2013-01-01

    This book will be a basic, step-by-step tutorial, which will help readers take advantage of all that Spark has to offer.Fastdata Processing with Spark is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too much to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  6. Contribution to the study of an lpg jet in the combustion chamber of a spark-ignition engine; Contribution a l'etude d'un jet de gpl dans la chambre de combustion d'un moteur a allumage commande, pour differentes strategies d'injection

    Energy Technology Data Exchange (ETDEWEB)

    Duong Viet, D.

    2002-07-01

    It appears tempting to combine the less polluting combustion of LPG with the energy performances of a direct injection spark-ignition engine. To this aim the study of high pressure injection of a liquid LPG jet, directly inside the combustion chamber of an engine was performed in two ways: Experimental studies: one with fast cinematography and another with the method of Doppler phases in an one-cylinder 'transparent' engine for various conditions of injection and without combustion. They respectively deliver empirical laws for the jet development and some informations about size and speed of the droplets of LPG. A modeling of the jet could then be made on the basis of a turbulent and deviated jet the parameters of which could be adjusted using results of the preceding experimental study. (author)

  7. SparkRS - Spark for Remote Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is Spark-RS, an open source software project that enables GPU-accelerated remote sensing workflows in an Apache Spark distributed computing...

  8. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  9. Formation of small sparks

    International Nuclear Information System (INIS)

    Barreto, E.; Jurenka, H.; Reynolds, S.I.

    1977-01-01

    The formation of a small incendiary spark at atmospheric pressure is identified with the transition from a weakly to a strongly ionized plasma. It is shown that initial gaseous ionization produced by avalanches and/or streamers always creates a high-temperature ideal electron gas that can shield the applied voltage difference and reduce ionization in the volume of the gas. The electron gas is collision dominated but able to maintain its high temperature, for times long compared to discharge events, through long-range Coulomb forces. In fact, electrons in the weakly ionized plasma constitute a collisionless independent fluid with a thermodynamic state that can be affected directly by field or density changes. Accordingly, with metal electrodes, cathode spot emission is always associated with the transition to a strongly ionized plasma. Neutral heating can be accomplished in two different ways. Effective dispersal of the electrons from the cathode leads to electron heating dominated by diffusion effects. Conversely, a fast rate of emission or rapid field changes can produce nonlinear wave propagation. It is shown that solitary waves are possible, and it is suggested that some spark transitions are associated with shock waves in the collisionless electron gas. In either the diffuse or nonlinear regime, neutral gas heating is controlled by collisions of ions with isotropic thermal electrons. This interaction is always subsequent to changes in state of the electron gas population. The basic results obtained should apply to all sparks

  10. Brookhaven National Laboratory's multiparticle spectrometer drift chamber system

    International Nuclear Information System (INIS)

    Etkin, A.; Kramer, M.A.

    1979-01-01

    A system of drift chambers is being built to replace the present spark chambers in the Brookhaven National Laboratory's Multiparticle Spectrometer. This system will handle a beam of approx. 3 million particles per second and have a resolution of 200 μm. A summary of the status of the chambers and the custom integrated circuits is presented. The data acquisition system is described. Prototype chambers have been built and tested with results that are consistent with the expected chamber properties

  11. Stability of Streamer Chamber

    Science.gov (United States)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi

    1982-08-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result.

  12. Stability of streamer chamber

    International Nuclear Information System (INIS)

    Wada, Toshiaki; Ogawa, Masato; Takahashi, Kaoru; Sugiyama, Tsunetoshi; Kobayashi, Shigeharu; Kohno, Hirobumi.

    1982-01-01

    The quality of tracks obtained from a streamer chamber is studied through the measurement of the streamer brightness. The stability of streamer tracks depends on the value of the high voltage applied and its shape. By using a single conical-type spark gap as the pulse shaper, stable brightness of the streamer tracks is attained. The data on the streamer brightness are compared with the result by Bulos et al. and it is found that the brightness is more strongly affected by field parameters than in their result. (author)

  13. Oblique Photographs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes photographs of marine mammals and sea turtles taken in the field. Most are lateral views of animals that are used to confirm species identity...

  14. Vertical Photographs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set includes of photographs of marine mammals and sea turtles taken with high resolution cameras mounted in airplanes, unmanned platforms or the bow of...

  15. Fast data processing with Spark

    CERN Document Server

    Sankar, Krishna

    2015-01-01

    Fast Data Processing with Spark - Second Edition is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too big to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  16. Tool grinding and spark testing

    Science.gov (United States)

    Widener, Edward L.

    1993-01-01

    The objectives were the following: (1) to revive the neglected art of metal-sparking; (2) to promote quality-assurance in the workplace; (3) to avoid spark-ignited explosions of dusts or volatiles; (4) to facilitate the salvage of scrap metals; and (5) to summarize important references.

  17. Primary Science Interview: Science Sparks

    Science.gov (United States)

    Bianchi, Lynne

    2016-01-01

    In this "Primary Science" interview, Lynne Bianchi talks with Emma Vanstone about "Science Sparks," which is a website full of creative, fun, and exciting science activity ideas for children of primary-school age. "Science Sparks" started with the aim of inspiring more parents to do science at home with their…

  18. Ionization chamber

    International Nuclear Information System (INIS)

    Jilbert, P.H.

    1975-01-01

    The invention concerns ionization chambers with particular reference to air-equivalent ionization chambers. In order to ensure that similar chambers have similar sensitivities and responses the surface of the chamber bounding the active volume carries a conducting material, which may be a colloidal graphite, arranged in the form of lines so that the area of the conducting material occupies only a small proportion of the area of said surface. (U.S.)

  19. 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

  20. MV controlled spark gap

    International Nuclear Information System (INIS)

    Evdokimovich, V.M.; Evlampiev, S.B.; Korshunov, G.S.; Nikolaev, V.A.; Sviridov, Yu.F.; Khmyrov, V.V.

    1980-01-01

    A megavolt gas-filled trigatron gap with a sectional gas-discharge chamber having a more than three-fold range of operating voltages is described. The discharge chamber consists of ten sections, each 70 mm thick, made of organic glass. The sections are separated one from another by aluminium gradient rings to which ohmic voltage divider is connected. Insulational sections and gradient rings are braced between themselves by means of metal flanges through gaskets made of oil-resistant rubber with the help of fiberglass-laminate pins. The gap has two electrodes 110 mm in diameter. The trigatron ignition assembly uses a dielectric bushing projecting over the main electrode plane. Use has been made of a gas mixture containing 10% of SF 6 and 90% of air making possible to ensure stable gap operation without readjusting in the voltage range from 0.4 to 1.35 MV. The operation time lag in this range is equal to 10 μs at a spread of [ru

  1. Spark formation as a moving boundary process

    Science.gov (United States)

    Ebert, Ute

    2006-03-01

    The growth process of spark channels recently becomes accessible through complementary methods. First, I will review experiments with nanosecond photographic resolution and with fast and well defined power supplies that appropriately resolve the dynamics of electric breakdown [1]. Second, I will discuss the elementary physical processes as well as present computations of spark growth and branching with adaptive grid refinement [2]. These computations resolve three well separated scales of the process that emerge dynamically. Third, this scale separation motivates a hierarchy of models on different length scales. In particular, I will discuss a moving boundary approximation for the ionization fronts that generate the conducting channel. The resulting moving boundary problem shows strong similarities with classical viscous fingering. For viscous fingering, it is known that the simplest model forms unphysical cusps within finite time that are suppressed by a regularizing condition on the moving boundary. For ionization fronts, we derive a new condition on the moving boundary of mixed Dirichlet-Neumann type (φ=ɛnφ) that indeed regularizes all structures investigated so far. In particular, we present compact analytical solutions with regularization, both for uniformly translating shapes and for their linear perturbations [3]. These solutions are so simple that they may acquire a paradigmatic role in the future. Within linear perturbation theory, they explicitly show the convective stabilization of a curved front while planar fronts are linearly unstable against perturbations of arbitrary wave length. [1] T.M.P. Briels, E.M. van Veldhuizen, U. Ebert, TU Eindhoven. [2] C. Montijn, J. Wackers, W. Hundsdorfer, U. Ebert, CWI Amsterdam. [3] B. Meulenbroek, U. Ebert, L. Schäfer, Phys. Rev. Lett. 95, 195004 (2005).

  2. Turbulent spark-jet ignition in SI gas fuelled engine

    Directory of Open Access Journals (Sweden)

    Pielecha Ireneusz

    2017-01-01

    Full Text Available The article contains a thermodynamic analysis of a new combustion system that allows the combustion of stratified gas mixtures with mean air excess coefficient in the range 1.4-1.8. Spark ignition was used in the pre-chamber that has been mounted in the engine cylinder head and contained a rich mixture out of which a turbulent flow of ignited mixture is ejected. It allows spark-jet ignition and the turbulent combustion of the lean mixture in the main combustion chamber. This resulted in a two-stage combustion system for lean mixtures. The experimental study has been conducted using a single-cylinder test engine with a geometric compression ratio ε = 15.5 adapted for natural gas supply. The tests were performed at engine speed n = 2000 rpm under stationary engine load when the engine operating parameters and toxic compounds emissions have been recorded. Analysis of the results allowed to conclude that the evaluated combustion system offers large flexibility in the initiation of charge ignition through an appropriate control of the fuel quantities supplied into the pre-chamber and into the main combustion chamber. The research concluded with determining the charge ignition criterion for a suitably divided total fuel dose fed to the cylinder.

  3. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  4. Bright Sparks of Our Future!

    Science.gov (United States)

    Riordan, Naoimh

    2016-04-01

    My name is Naoimh Riordan and I am the Vice Principal of Rockboro Primary School in Cork City, South of Ireland. I am a full time class primary teacher and I teach 4th class, my students are aged between 9-10 years. My passion for education has developed over the years and grown towards STEM (Science, Technology, Engineering and Mathematics) subjects. I believe these subjects are the way forward for our future. My passion and beliefs are driven by the unique after school programme that I have developed. It is titled "Sparks" coming from the term Bright Sparks. "Sparks" is an after school programme with a difference where the STEM subjects are concentrated on through lessons such as Science, Veterinary Science Computer Animation /Coding, Eco engineering, Robotics, Magical Maths, Chess and Creative Writing. All these subjects are taught through activity based learning and are one-hour long each week for a ten-week term. "Sparks" is fully inclusive and non-selective which gives all students of any level of ability an opportunity to engage into these subjects. "Sparks" is open to all primary students in County Cork. The "Sparks" after school programme is taught by tutors from the different Universities and Colleges in Cork City. It works very well because the tutor brings their knowledge, skills and specialised equipment from their respective universities and in turn the tutor gains invaluable teaching practise, can trial a pilot programme in a chosen STEM subject and gain an insight into what works in the physical classroom.

  5. Bubble chamber: Omega production and decay

    CERN Document Server

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  6. High counting rate resistive-plate chamber

    International Nuclear Information System (INIS)

    Peskov, V.; Anderson, D.F.; Kwan, S.

    1993-05-01

    Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast ( 5 counts/mm 2 . A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity (≥10 10 Ω·cm) materials. In practice RPCs are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm 2 , leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm's law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases

  7. Ignition of turbulent swirling n-heptane spray flames using single and multiple sparks

    Energy Technology Data Exchange (ETDEWEB)

    Marchionea, T.; Ahmeda, S.F.; Mastorakos, E. [Department of Engineering, University of Cambridge (United Kingdom)

    2009-01-15

    This paper examines ignition processes of an n-heptane spray in a flow typical of a liquid-fuelled burner. The spray is created by a hollow-cone pressure atomiser placed in the centre of a bluff body, around which swirling air induces a strong recirculation zone. Ignition was achieved by single small sparks of short duration (2 mm; 0.5 ms), located at various places inside the flow so as to identify the most ignitable regions, or larger sparks of longer duration (5 mm; 8 ms) repeated at 100 Hz, located close to the combustion chamber enclosure so as to mimic the placement and characteristics of a gas turbine combustor surface igniter. The air and droplet velocities, the droplet diameter, and the total (i.e. liquid plus vapour) equivalence ratio were measured in inert flow by phase Doppler anemometry and sampling respectively. Fast camera imaging suggested that successful ignition events were associated with flamelets that propagated back towards the spray nozzle. Measurements of ignition probability with the single spark showed that localised ignition inside the spray is more likely to result in successful flame establishment when the spark is located in a region of negative velocity, relatively small droplet Sauter mean diameter, and mean equivalence ratio within the flammability limits. Ignition with the single spark was not possible at the location where the multiple spark experiments were performed. For those, the multiple spark sequence lasted approximately 1 to 5 s. It was found that a long spark sequence increases the ignition efficiency, which reached a maximum of 100% at the axial distance where the recirculation zone had maximum width. Ignition was not feasible with the spark downstream of about two burner diameters. Visualisation showed that small flame kernels emanate very often from the spark, which can be stretched as far as 20 mm from the electrodes by the turbulent velocity fluctuations. These kernels survive very little time. Successful overall

  8. Spark channel propagation in a microbubble liquid

    Energy Technology Data Exchange (ETDEWEB)

    Panov, V. A.; Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru; Vetchinin, S. P.; Pecherkin, V. Ya.; Son, E. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-11-15

    Experimental study on the development of the spark channel from the anode needle under pulsed electrical breakdown of isopropyl alcohol solution in water with air microbubbles has been performed. The presence of the microbubbles increases the velocity of the spark channel propagation and increases the current in the discharge gap circuit. The observed rate of spark channel propagation in microbubble liquid ranges from 4 to 12 m/s, indicating the thermal mechanism of the spark channel development in a microbubble liquid.

  9. Photographic materials

    International Nuclear Information System (INIS)

    1980-01-01

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. A photographic, chemically sensitised silver halide emulsion is described, containing 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The remaining silver halide, if any, is silver bromide and/or silver iodide. The silver halide grains are grown in the presence of ammonia, an excess of chloride ions and tetraazaindene growth controller. Examples illustrating the invention are given. (U.K.)

  10. Pressure dependence of the spark constant

    Energy Technology Data Exchange (ETDEWEB)

    Hess, H; Radtke, R; Deparade, W [Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Elektronenphysik

    1978-02-21

    The author's theory on the development of LTE plasmas in low-inductance spark discharges has proved to be a useful tool in predicting the electric behaviour of such sparks. Their earlier experimental work was restricted to only one initial pressure, and in this paper they extend the examined pressure range to obtain some general conclusions on the pressure dependence of the spark behaviour.

  11. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

    Doi, Yoshikuni; Araoka, Osamu; Hayashi, Kohei; Hayashi, Yoshio; Hirabayashi, Hiromi.

    1978-03-01

    A medium size hydrogen bubble chamber has been constructed at the National Laboratory for High Energy Physics, KEK. The bubble chamber has been designed to be operated with a maximum rate of three times per half a second in every two second repetition time of the accelerator, by utilizing a hydraulic expansion system. The bubble chamber has a one meter diameter and a visible volume of about 280 l. A three-view stereo camera system is used for taking photographic pictures of the chamber. A 2 MW bubble chamber magnet is constructed. The main part of the bubble chamber vessel is supported by the magnet yoke. The magnet gives a maximum field of 18.4 kG at the centre of the fiducial volume of the chamber. The overall system of the KEK 1 m hydrogen bubble chamber facility is described in some detail. Some operational characteristics of the facility are also reported. (auth.)

  12. 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

  13. 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.

  14. Drift chamber

    International Nuclear Information System (INIS)

    Inagaki, Yosuke

    1977-01-01

    Drift chamber is becoming an important detector in high energy physics as a precision and fast position detector because of its high spatial resolution and count-rate. The basic principle is that it utilizes the drift at constant speed of electrons ionized along the tracks of charged particles towards the anode wire in the nearly uniform electric field. The method of measuring drift time includes the analog and digital ones. This report describes about the construction of and the application of electric field to the drift chamber, mathematical analysis on the electric field and equipotential curve, derivation of spatial resolution and the factor for its determination, and selection of gas to be used. The performance test of the chamber was carried out using a small test chamber, the collimated β source of Sr-90, and 500 MeV/C electron beam from the 1.3 GeV electron synchrotron in the Institute of Nuclear Study, University of Tokyo. Most chambers to date adopted one dimensional read-out, but it is very advantageous if the two dimensional read-out is feasible with one chamber when the resolution in that direction is low. The typical methods of delay line and charge division for two dimensional read-out are described. The development of digital read-out system is underway, which can process the signal of a large scale drift chamber at high speed. (Wakatsuki, Y.)

  15. Fiber coupled optical spark delivery system

    Science.gov (United States)

    Yalin, Azer; Willson, Bryan; Defoort, Morgan

    2008-08-12

    A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

  16. Photographic materials

    International Nuclear Information System (INIS)

    Jamieson, P.B.

    1980-01-01

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. The film material is comprised of a base having at least one layer of a photographic silver halide emulsion and a yellow filter dye screening the emulsion from visible radiation. The silver halide emulsion contains 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The nature and properties of the yellow filter dye are described. When recording an X-ray image, the film is loaded into the camera under white safelight conditions from which light of wavelength shorter than 400 nm is excluded. The film is in contact with one or more phosphor screens capable when struck by X-rays of emitting ultraviolet radiation, the screens having a peak ultraviolet emission within the wavelength range of 250-380 nm. After X-ray exposure, the film is removed and developed. Two examples illustrating the invention are given. (U.K.)

  17. 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.

  18. 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.

  19. New applications of photographic materials in science and technique

    International Nuclear Information System (INIS)

    Buschmann, H.T.; Deml, R.; Duville, R.; Philippaerts, H.; Bollen, R.; Ranz, E.

    1976-01-01

    In spite of some disatvantages photographic materials based on silver halides possess the outstanding feature of high sensitivity. So again and again special photographic materials have been developed for new techniques including information storage. This contribution reports on some special photographic materials and it briefly discusses some applications. Materials are discussed in detail for holography, carrier-frequency photography, producing masks for integrated circuits, recording equidensities, bubble chamber photography, and for neutron-radiography. (orig.) [de

  20. Ionization chamber

    International Nuclear Information System (INIS)

    1977-01-01

    An improved ionization chamber type X-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is placed next to the anode and is maintained at a voltage intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting towards the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  1. Ionization chambers

    International Nuclear Information System (INIS)

    Boag, J.W.

    1987-01-01

    Although a variety of solid-state and chemical methods for measuring radiation dose have been developed in recent decades and calorimetry can now provide an absolute standard of reference, ionization dosimetry retains its position as the most widely used, most convenient, and, in most situations, most accurate method of measuring either exposure or absorbed dose. The ionization chamber itself is the central element in this system of dosimetry. In this chapter the principles governing the construction and operation of ionization chambers of various types are examined. Since the ionization chambers now in general use are nearly all of commercial manufacture, the emphasis is on operating characteristics and interpretation of measurements rather than on details of construction, although some knowledge of the latter is often required when applying necessary corrections to the measured quantities. Examples are given of the construction of typical chambers designed for particular purposes, and the methods of calibrating them are discussed

  2. Studies of particle interactions in bubble chamber, spark chambers and counter experiments. Annual progress report

    International Nuclear Information System (INIS)

    Holloway, L.E.; O'Halloran, T.A. Jr.; Simmons, R.O.

    1983-07-01

    During the past six years we have carried out and planned experiments which predominantly studied the production and decay of particles containing charmed quarks. A series of photoproduction and neutron production experiments started with the very early observation of the production of J/psi by neutrons and by photons at Fermilab. From subsequent experiments using these neutral beams and the basic detecting system, we have reported results on the photoproduction of the Λ/sub c/ charmed baryon and the D and D* charmed mesons. More recent runs are studying the high energy photoproduction of vector mesons including the psi'. The present experiment in this sequence is using neutrons to produce a large number of D mesons. Another series of experiments at Fermilab set out to study the hadronic production of charmed mesons. The Chicago Cyclotron facility was modified with a detector sensitive to various possible production mechanisms. The experiments were a success; clean signals of D mesons were observed to be produced by pions, and also the production of chi/sub c/ with the subsequent decay via a γ-ray to psi was observed. The charmonium experiments run this year have better photon resolution for measuring the decays of chi/sub c/ to psi. We are part of a collaboration which is working on the Collider Detector Facility for Fermilab. The CDF at Fermilab is a possible source of (weak) intermediate vector bosons from the collisions of protons and anti-protons. Our responsibilities in the CDF include both the construction of the muon detector and the designing, planning, and testing of the FASTBUS electronics. The second part of our weak interaction program is the Neutrino Oscillation experiment which is now under construction at Brookhaven

  3. Sample preparations for spark source mass spectrography

    International Nuclear Information System (INIS)

    Catlett, C.W.; Rollins, M.B.; Griffin, E.B.; Dorsey, J.G.

    1977-10-01

    Methods have been developed for the preparation of various materials for spark source mass spectrography. The essential features of these preparations (all which can provide adequate precision in a cost-effective manner) consist in obtaining spark-stable electrode sample pieces, a common matrix, a reduction of anomolous effects in the spark, the incorporation of a suitable internal standard for plate response normalization, and a reduction in time

  4. The pressure dependence of the spark constant

    International Nuclear Information System (INIS)

    Hess, H.; Radtke, R.; Deparade, W.

    1978-01-01

    The author's theory on the development of LTE plasmas in low-inductance spark discharges has proved to be a useful tool in predicting the electric behaviour of such sparks. Their earlier experimental work was restricted to only one initial pressure, and in this paper they extend the examined pressure range to obtain some general conclusions on the pressure dependence of the spark behaviour. (author)

  5. New spark test device for material characterization

    CERN Document Server

    Kildemo, Morten

    2004-01-01

    An automated spark test system based on combining field emission and spark measurements, exploiting a discharging capacitor is investigated. In particular, the remaining charge on the capacitor is analytically solved assuming the field emitted current to follow the Fowler Nordheim expression. The latter allows for field emission measurements from pA to A currents, and spark detection by complete discharge of the capacitor. The measurement theory and experiments on Cu and W are discussed.

  6. Cloud Chamber

    DEFF Research Database (Denmark)

    Gfader, Verina

    Cloud Chamber takes its roots in a performance project, titled The Guests 做东, devised by Verina Gfader for the 11th Shanghai Biennale, ‘Why Not Ask Again: Arguments, Counter-arguments, and Stories’. Departing from the inclusion of the biennale audience to write a future folk tale, Cloud Chamber......: fiction and translation and translation through time; post literacy; world picturing-world typing; and cartographic entanglements and expressions of subjectivity; through the lens a social imaginary of worlding or cosmological quest. Art at its core? Contributions by Nikos Papastergiadis, Rebecca Carson...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. The wide gap resistive plate chamber

    International Nuclear Information System (INIS)

    Crotty, I.; Lamas Valverde, J.; Hatzifotiadou, D.; Williams, M.C.S.; Zichichi, A.

    1995-01-01

    The resistive plate chamber (RPC) has good time and position resolution; these factors (coupled to its simple construction) make it an attractive candidate for muon trigger systems at future colliders. However, operated in spark mode, the RPC has severe rate problems that make it unusable above 10 Hz/cm 2 . We have previously published our results concerning the operation of the RPC in spark and in avalanche mode; we have shown that the rate limit can be increased to 150 Hz/cm 2 if the RPC is operated in avalanche mode. Here, we discuss the performance of chambers with 6 and 8 mm gas gaps (compared to the more usual 2 mm gap). We outline the reasons for this choice, and also discuss anode versus cathode strip readout. We have measured the efficiency versus flux, and also show that an enhanced rate limit can be obtained if only a small region of the chamber is exposed to the beam (spot illumination). Finally we have tested the performance of chambers constructed with other materials for the resistiv e plate and compare it to chambers constructed with our preferred plastic, melamine laminate. (orig.)

  12. Holographic processing of track chamber data

    Energy Technology Data Exchange (ETDEWEB)

    Bykovsky, Y A; Larkin, A I; Markilov, A A; Starikov, S N [Moskovskij Fiziko-Tekhnicheskij Inst. (USSR)

    1975-12-01

    The holographic pattern recognition method was applied for processing of track chamber photographs. Experiments on detection of such events as a definitely directed track, an angle formed by two tracks, a three-pronged star, a definitely curved track were performed by using models. It is proposed to recognize these events in a filmshot by the shape of correlation signals. The experiment to recognize the event in a real bubble chamber filmshot was realized; requirements to the processing films were determined.

  13. Programmable spark counter of tracks

    International Nuclear Information System (INIS)

    Denisov, A.E.; Nikolaev, V.A.; Vorobjev, I.B.

    2005-01-01

    For the purpose, a new set-the programmable all-automatic spark counter AIST-4-has been developed and manufactured. Compared to our previous automated spark counter ISTRA, which was operated by the integrated fixed program, the new set is operated completely by a personal computer. The mechanism for pressing and pulling the aluminized foil is put into action by a step motor operated by a microcontroller. The step motor turns an axle. The axle has two eccentrics. One of them moves a pressing plate up and down. The second eccentric moves the aluminized foil by steps of ∼15mm after the end of each pulse counting. One turnover of the axle corresponds to one pulse count cycle. The step motor, the high-voltage block and the pulse count block are operated by the microcontroller PIC 16C84 (Microstar). The set can be operated either manually by keys on the front panel or by a PC using dialogue windows for radon or neutron measurements (for counting of alpha or fission fragment tracks). A number of algorithms are developed: the general procedures, the automatic stopping of the pulse counting, the calibration curve, determination of the count characteristics and elimination of the short circuit in a track

  14. The BEBC chamber body and piston in CERN's Microcosm Garden.

    CERN Multimedia

    Laurent Guiraud

    1997-01-01

    The Big European Bubble Chamber (BEBC) was used to photograph the tracks left by particles as they passed through a heated liquid as it was expanded. When closed in 1984, 6.3 million photographs had been taken on 3000 km of film for 22 neutrino and hadron experiments using beams from the PS and SPS accelerators.

  15. Modelling auto ignition of hydrogen in a jet ignition pre-chamber

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

    2010-04-15

    Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. The paper describes the operation of the spark-less jet ignition pre-chamber coupling CFD and CAE engine simulations to allow component selection and engine performance evaluation. (author)

  16. Glacier Photograph Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Glacier Photograph Collection is a database of photographs of glaciers from around the world, some dating back to the mid-1850's, that provide an historical...

  17. Spark gap produced plasma diagnostics

    International Nuclear Information System (INIS)

    Chang, H.Y.

    1990-01-01

    A Spark Gap (Applied voltage : 2-8KV, Capacitor : 4 Micro F. Dia of the tube : 1 inch, Electrode distance : .3 ∼.5 inch) was made to generate a small size dynamic plasma. To measure the plasma density and temperature as a function of time and position, we installed and have been installing four detection systems - Mach-Zehnder type Interferometer for the plasma refractivity, Expansion speed detector using two He-Ne laser beams, Image Processing using Lens and A Optical-Fiber Array for Pointwise Radiation Sensing, Faraday Rotation of a Optical Fiber to measure the azimuthal component of B-field generated by the plasma drift. These systems was used for the wire explosion diagnostics, and can be used for the Laser driven plasma also

  18. Spark-safe power source

    Energy Technology Data Exchange (ETDEWEB)

    Mester, I M; Konushkin, N A; Nevozinskiy, A K; Rubinshteyn, B Sh; Serov, V I; Vasnev, M A

    1981-01-01

    A shortcoming of the known power sources is their low reliability. The purpose of the invention is to improve the reliability of the device. This is achieved because the spark-safe power source is equipped with a by-passing transistor and potentiometer, and also a generator of control interruptions in the circuit, an I-element, first separating transformer, control block, second separating transformer whose secondary winding has a relay winding whose contacts are connected to the load circuit are connected in series. The generator of control separations of the circuit is connected to the base of the by-passing transistor and to the power source outlet, the potentiometer is connected in series to the main thyristor. The middle point of the potentiometer is connected to the second inlet of the I-element.

  19. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  20. THE EFFECT OF COMPRESSION RATIO VARIATIONS ON THE ENGINE PERFORMANCE PARAMETRES IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Yakup SEKMEN

    2005-01-01

    Full Text Available Performance of the spark ignition engines may be increased by changing the geometrical compression ratio according to the amount of charging in cylinders. The designed geometrical compression ratio can be realized as an effective compression ratio under the full load and full open throttle conditions since the effective compression ratio changes with the amount of charging into the cylinder in spark ignition engines. So, this condition of the spark ignition engines forces designers to change their geometrical compression ratio according to the amount of charging into the cylinder for improvement of performance and fuel economy. In order to improve the combustion efficiency, fuel economy, power output, exhaust emissions at partial loads, compression ratio must be increased; but, under high load and low speed conditions to prevent probable knock and hard running the compression ratio must be decreased gradually. In this paper, relation of the performance parameters to compression ratio such as power, torque, specific fuel consumption, cylindir pressure, exhaust gas temperature, combustion chamber surface area/volume ratio, thermal efficiency, spark timing etc. in spark ignition engines have been investigated and using of engines with variable compression ratio is suggested to fuel economy and more clear environment.

  1. Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator.

    Science.gov (United States)

    Reddy, C S; Patel, A S; Naresh, P; Sharma, Archana; Mittal, K C

    2014-06-01

    The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap. A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs-1 s was developed. A matrix transformer topology is used to get fast rise times by reducing L(l)C(d) product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0-2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.

  2. GeoSpark SQL: An Effective Framework Enabling Spatial Queries on Spark

    Directory of Open Access Journals (Sweden)

    Zhou Huang

    2017-09-01

    Full Text Available In the era of big data, Internet-based geospatial information services such as various LBS apps are deployed everywhere, followed by an increasing number of queries against the massive spatial data. As a result, the traditional relational spatial database (e.g., PostgreSQL with PostGIS and Oracle Spatial cannot adapt well to the needs of large-scale spatial query processing. Spark is an emerging outstanding distributed computing framework in the Hadoop ecosystem. This paper aims to address the increasingly large-scale spatial query-processing requirement in the era of big data, and proposes an effective framework GeoSpark SQL, which enables spatial queries on Spark. On the one hand, GeoSpark SQL provides a convenient SQL interface; on the other hand, GeoSpark SQL achieves both efficient storage management and high-performance parallel computing through integrating Hive and Spark. In this study, the following key issues are discussed and addressed: (1 storage management methods under the GeoSpark SQL framework, (2 the spatial operator implementation approach in the Spark environment, and (3 spatial query optimization methods under Spark. Experimental evaluation is also performed and the results show that GeoSpark SQL is able to achieve real-time query processing. It should be noted that Spark is not a panacea. It is observed that the traditional spatial database PostGIS/PostgreSQL performs better than GeoSpark SQL in some query scenarios, especially for the spatial queries with high selectivity, such as the point query and the window query. In general, GeoSpark SQL performs better when dealing with compute-intensive spatial queries such as the kNN query and the spatial join query.

  3. AROMA-AIRWICK: a CHLOE/CDC-3600 system for the automatic identification of spark images and their association into tracks

    International Nuclear Information System (INIS)

    Clark, R.K.

    The AROMA-AIRWICK System for CHLOE, an automatic film scanning equipment built at Argonne by Donald Hodges, and the CDC-3600 computer is a system for the automatic identification of spark images and their association into tracks. AROMA-AIRWICK has been an outgrowth of the generally recognized need for the automatic processing of high energy physics data and the fact that the Argonne National Laboratory has been a center of serious spark chamber development in recent years

  4. Adaptation of multiwire chambers to some recent experiments in elementary particle physics

    International Nuclear Information System (INIS)

    Comby, G.

    1977-01-01

    Three realizations of gas multiplication detectors are presented in the field of multiwire chambers. Le 'NEUTRINO' experiment is intended for investigating neutrino interactions at energies as high as possible with using drift chambers. The 'LEZARD' experiment is intended for investigating lepton and hadron production at high transverse momentum in hadron-nucleon collisions up to the higher energies attainable at SPS (use of a multiwire proportional chamber), the apparatus has the performance of a spectrometer. A spark chamber equipped with memories has been developed for controlling bubble chamber experiments. Emphasis is put on the evolution towards detectors associated with 'another thing' to obtain a more specific operation: such as the plasma memory and spark chamber association, some possible association with function gaps is pointed out (delay function, homothetic function) [fr

  5. Chamber transport

    International Nuclear Information System (INIS)

    Olson, Craig L.

    2001-01-01

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system

  6. SPARK: Adapting Keyword Query to Semantic Search

    Science.gov (United States)

    Zhou, Qi; Wang, Chong; Xiong, Miao; Wang, Haofen; Yu, Yong

    Semantic search promises to provide more accurate result than present-day keyword search. However, progress with semantic search has been delayed due to the complexity of its query languages. In this paper, we explore a novel approach of adapting keywords to querying the semantic web: the approach automatically translates keyword queries into formal logic queries so that end users can use familiar keywords to perform semantic search. A prototype system named 'SPARK' has been implemented in light of this approach. Given a keyword query, SPARK outputs a ranked list of SPARQL queries as the translation result. The translation in SPARK consists of three major steps: term mapping, query graph construction and query ranking. Specifically, a probabilistic query ranking model is proposed to select the most likely SPARQL query. In the experiment, SPARK achieved an encouraging translation result.

  7. Experimental study of a spark-gap

    International Nuclear Information System (INIS)

    Bruzzone, H.; Moreno, C.; Vieytes, R.

    1990-01-01

    Some experimental results concerning to the resistance of an atmospheric pressure spark-gap, operating in the self breakdown regime are presented. The influence of the energy discharging through the gap on this resistance is discussed. (Author)

  8. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

  9. A Experimental Study of the Growth of Laser Spark and Electric Spark Ignited Flame Kernels.

    Science.gov (United States)

    Ho, Chi Ming

    1995-01-01

    Better ignition sources are constantly in demand for enhancing the spark ignition in practical applications such as automotive and liquid rocket engines. In response to this practical challenge, the present experimental study was conducted with the major objective to obtain a better understanding on how spark formation and hence spark characteristics affect the flame kernel growth. Two laser sparks and one electric spark were studied in air, propane-air, propane -air-nitrogen, methane-air, and methane-oxygen mixtures that were initially at ambient pressure and temperature. The growth of the kernels was monitored by imaging the kernels with shadowgraph systems, and by imaging the planar laser -induced fluorescence of the hydroxyl radicals inside the kernels. Characteristic dimensions and kernel structures were obtained from these images. Since different energy transfer mechanisms are involved in the formation of a laser spark as compared to that of an electric spark; a laser spark is insensitive to changes in mixture ratio and mixture type, while an electric spark is sensitive to changes in both. The detailed structures of the kernels in air and propane-air mixtures primarily depend on the spark characteristics. But the combustion heat released rapidly in methane-oxygen mixtures significantly modifies the kernel structure. Uneven spark energy distribution causes remarkably asymmetric kernel structure. The breakdown energy of a spark creates a blast wave that shows good agreement with the numerical point blast solution, and a succeeding complex spark-induced flow that agrees reasonably well with a simple puff model. The transient growth rates of the propane-air, propane-air -nitrogen, and methane-air flame kernels can be interpreted in terms of spark effects, flame stretch, and preferential diffusion. For a given mixture, a spark with higher breakdown energy produces a greater and longer-lasting enhancing effect on the kernel growth rate. By comparing the growth

  10. Personnel photographic film dosimetry

    International Nuclear Information System (INIS)

    Keirim-Markus, I.B.

    1981-01-01

    Technology of personnel photographic film dosimetry (PPD) based on the photographic effect of ionizing radiation is described briefly. Kinds of roentgen films used in PPD method are enumerated, compositions of a developer and fixing agents for these films are given [ru

  11. Fabrication of resistive plate chamber using bakelite

    International Nuclear Information System (INIS)

    Neog, Himangshu; Bhuyan, M.R.; Biswas, S.; Mohanty, B.; Mohanty, Rudranarayan; Rudra, Sharmili; Sahu, P.K.; Sahu, S.

    2014-01-01

    Now a days Resistive Plate Chamber (RPC) is one of the most important detectors in the High Energy Physics (HEP) experiments. RPC is a gas filled detector utilizing a constant and uniform electric field produced between two parallel electrode plates made of a material with high bulk resistivity e.g. glass or bakelite. RPC has good time resolution (1-2 ns) and spatial resolution (∼ cm). The high resistance of RPC plate limits the spark size produced after the ionization of gas due to the passing charged particle. This contribution discusses building of a RPC using bakelite (local sources) and the measurement of the surface resistivity of the detector

  12. Scattering profiles of sparks and combustibility of filter against hot sparks

    International Nuclear Information System (INIS)

    Asazuma, Shinichiro; Okada, Takashi; Kashiro, Kashio

    2004-01-01

    The glove-box dismantling facility in the Plutonium Fuel Production Facility is developed to dismantle after-service glove-boxes with remote-controlled devices such as an arm-type manipulator. An abrasive wheel cutter, which is used to size reduce the gloveboxes, generates sparks during operation. This dispersing spark was a problem from the fire prevention point of view. A suitable spark control measures for this operation were required. We developed panels to minimize spark dispersion, shields to prevent the income of sparks to the pre-filter, and incombustible pre-filters. The equipment was tested and effectiveness was confirmed. This report provides the results of these tests. (author)

  13. 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...

  14. Spark - a modern approach for distributed analytics

    CERN Multimedia

    CERN. Geneva; Kothuri, Prasanth

    2016-01-01

    The Hadoop ecosystem is the leading opensource platform for distributed storing and processing big data. It is a very popular system for implementing data warehouses and data lakes. Spark has also emerged to be one of the leading engines for data analytics. The Hadoop platform is available at CERN as a central service provided by the IT department. By attending the session, a participant will acquire knowledge of the essential concepts need to benefit from the parallel data processing offered by Spark framework. The session is structured around practical examples and tutorials. Main topics: Architecture overview - work distribution, concepts of a worker and a driver Computing concepts of transformations and actions Data processing APIs - RDD, DataFrame, and SparkSQL

  15. Using SPARK as a Solver for Modelica

    Energy Technology Data Exchange (ETDEWEB)

    Wetter, Michael; Wetter, Michael; Haves, Philip; Moshier, Michael A.; Sowell, Edward F.

    2008-06-30

    Modelica is an object-oriented acausal modeling language that is well positioned to become a de-facto standard for expressing models of complex physical systems. To simulate a model expressed in Modelica, it needs to be translated into executable code. For generating run-time efficient code, such a translation needs to employ algebraic formula manipulations. As the SPARK solver has been shown to be competitive for generating such code but currently cannot be used with the Modelica language, we report in this paper how SPARK's symbolic and numerical algorithms can be implemented in OpenModelica, an open-source implementation of a Modelica modeling and simulation environment. We also report benchmark results that show that for our air flow network simulation benchmark, the SPARK solver is competitive with Dymola, which is believed to provide the best solver for Modelica.

  16. High performance Spark best practices for scaling and optimizing Apache Spark

    CERN Document Server

    Karau, Holden

    2017-01-01

    Apache Spark is amazing when everything clicks. But if you haven’t seen the performance improvements you expected, or still don’t feel confident enough to use Spark in production, this practical book is for you. Authors Holden Karau and Rachel Warren demonstrate performance optimizations to help your Spark queries run faster and handle larger data sizes, while using fewer resources. Ideal for software engineers, data engineers, developers, and system administrators working with large-scale data applications, this book describes techniques that can reduce data infrastructure costs and developer hours. Not only will you gain a more comprehensive understanding of Spark, you’ll also learn how to make it sing. With this book, you’ll explore: How Spark SQL’s new interfaces improve performance over SQL’s RDD data structure The choice between data joins in Core Spark and Spark SQL Techniques for getting the most out of standard RDD transformations How to work around performance issues i...

  17. 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...

  18. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1980-01-01

    A multi-chambered ionisation detector enables the amount of radiation entering each chamber from a single radioactive, eg β, source to be varied by altering the proportion of the source protruding into each chamber. Electrodes define chambers and an extended radioactive source is movable to alter the source length in each chamber. Alternatively, the source is fixed relative to outer electrodes but the central electrode may be adjusted by an attached support altering the chamber dimensions and hence the length of source in each. Also disclosed are a centrally mounted source tiltable towards one or other chamber and a central electrode tiltable to alter chamber dimensions. (U.K.)

  19. Chaotic combustion in spark ignition engines

    International Nuclear Information System (INIS)

    Wendeker, Miroslaw; Czarnigowski, Jacek; Litak, Grzegorz; Szabelski, Kazimierz

    2003-01-01

    We analyse the combustion process in a spark ignition engine using the experimental data of an internal pressure during the combustion process and show that the system can be driven to chaotic behaviour. Our conclusion is based on the observation of unperiodicity in the time series, suitable stroboscopic maps and a complex structure of a reconstructed strange attractor. This analysis can explain that in some circumstances the level of noise in spark ignition engines increases considerably due to nonlinear dynamics of a combustion process

  20. Radiography using photographic paper

    International Nuclear Information System (INIS)

    Gromov, Yu.V.; Kapustin, V.I.; Volkova, T.G.

    1982-01-01

    The possibility of radiographic control with application of ''Fototelegrafnaya BS'' photographic paper in conjunction with the ''Standart'' image intensifier as an X-ray image converter is studied. Investigations were made using steel samples 5 to 45 mm thick, X-ray radiation energy varied from 80 to 240 keV. Specifications of the image intensifier of the ''Standart type and photographic paper are given. It is shown, that the photographic paper improves the sensitivity of the method to the detection of small defects. The method provides standard and panoramic radioscopy, conservation of objective documentation, enables one to mechanize and automatize the process of photodevelopment. The application of the photographic paper is beneficial, its cost being six times as low as that of X-ray film

  1. Laser ignition - Spark plug development and application in reciprocating engines

    Science.gov (United States)

    Pavel, Nicolaie; Bärwinkel, Mark; Heinz, Peter; Brüggemann, Dieter; Dearden, Geoff; Croitoru, Gabriela; Grigore, Oana Valeria

    2018-03-01

    Combustion is one of the most dominant energy conversion processes used in all areas of human life, but global concerns over exhaust gas pollution and greenhouse gas emission have stimulated further development of the process. Lean combustion and exhaust gas recirculation are approaches to improve the efficiency and to reduce pollutant emissions; however, such measures impede reliable ignition when applied to conventional ignition systems. Therefore, alternative ignition systems are a focus of scientific research. Amongst others, laser induced ignition seems an attractive method to improve the combustion process. In comparison with conventional ignition by electric spark plugs, laser ignition offers a number of potential benefits. Those most often discussed are: no quenching of the combustion flame kernel; the ability to deliver (laser) energy to any location of interest in the combustion chamber; the possibility of delivering the beam simultaneously to different positions, and the temporal control of ignition. If these advantages can be exploited in practice, the engine efficiency may be improved and reliable operation at lean air-fuel mixtures can be achieved, making feasible savings in fuel consumption and reduction in emission of exhaust gasses. Therefore, laser ignition can enable important new approaches to address global concerns about the environmental impact of continued use of reciprocating engines in vehicles and power plants, with the aim of diminishing pollutant levels in the atmosphere. The technology can also support increased use of electrification in powered transport, through its application to ignition of hybrid (electric-gas) engines, and the efficient combustion of advanced fuels. In this work, we review the progress made over the last years in laser ignition research, in particular that aimed towards realizing laser sources (or laser spark plugs) with dimensions and properties suitable for operating directly on an engine. The main envisaged

  2. Modelling Spark Integration in Science Classroom

    Directory of Open Access Journals (Sweden)

    Marie Paz E. Morales

    2014-02-01

    Full Text Available The study critically explored how a PASCO-designed technology (SPARK ScienceLearning System is meaningfully integrated into the teaching of selected topics in Earth and Environmental Science. It highlights on modelling the effectiveness of using the SPARK Learning System as a primary tool in learning science that leads to learning and achievement of the students. Data and observation gathered and correlation of the ability of the technology to develop high intrinsic motivation to student achievement were used to design framework on how to meaningfully integrate SPARK ScienceLearning System in teaching Earth and Environmental Science. Research instruments used in this study were adopted from standardized questionnaires available from literature. Achievement test and evaluation form were developed and validated for the purpose of deducing data needed for the study. Interviews were done to delve into the deeper thoughts and emotions of the respondents. Data from the interviews served to validate all numerical data culled from this study. Cross-case analysis of the data was done to reveal some recurring themes, problems and benefits derived by the students in using the SPARK Science Learning System to further establish its effectiveness in the curriculum as a forerunner to the shift towards the 21st Century Learning.

  3. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  4. Ambient fields generated by a laser spark

    Czech Academy of Sciences Publication Activity Database

    Rohlena, Karel; Mašek, Martin

    2016-01-01

    Roč. 61, č. 2 (2016), s. 119-124 ISSN 0029-5922 R&D Projects: GA MŠk(CZ) LD14089; GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 Keywords : laser spark * radiation chemistry * field generation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.760, year: 2016

  5. Electro-spark machining of cadmium antimonide

    International Nuclear Information System (INIS)

    Ivanovskij, V.N.; Stepakhina, K.A.

    1975-01-01

    Experimental data on electrical erosion of the semiconductor material (cadmium antimonide) alloyed with tellurium are given. The potentialisies and expediency of using the electric-spark method of cutting cadmium antimonide ingots with the resistivity of 1 ohm is discussed. Cutting has been carried out in distilled water and in the air

  6. Pressure Indicating with Measuring Spark Plugs on a DI-Gasoline Engine - State of Technology; Druckindizierung mit Messzuendkerzen an einem DI-Ottomotor - Stand der Technik

    Energy Technology Data Exchange (ETDEWEB)

    Walter, T.; Brechbuehl, S.; Gossweiler, C.; Schnepf, M.; Wolfer, P. [Kistler Instrumente AG, Winterthur (Switzerland)

    2004-07-01

    For pressure indicating in gasoline engines, spark plugs with integrated pressure sensor are enabling for fast and efficient access to the combustion chamber. These socalled measuring spark plugs permit any engine to be set up for pressure-indicating within a minimum amount of time and without need for any preparation of an additional bore. Measuring spark plugs offer the user a number of immediate advantages: a) no need to modify the engine by drilling a separate bore to access the combustion chamber b) no modification of the geometry of the combustion chamber and thermal conditions c) suitable for on-board measurements, end-of-line checks and monitoring d) quick and easy installation and replacement In terms of costs, measuring spark plugs are also representing a beneficial alternative to separate indicating bores. The cost of designing, preparing and carrying out an additional bore in a cylinder head are typically many times the costs for a measuring spark plug, thus producing a significant cost saving. The main disadvantages of measuring spark plugs are as follows: 1) restricted to uncooled, low sensitivity miniature pressure sensors 2) the sensor element is exposed to an extraordinarily high thermal load 3) proximity to high voltage carries the risk of electromagnetic interference 4) the positioning between the valve seats means they are subject to heavy vibration 5) the incorporation of the pressure sensor results in more complex design. The purpose of this paper is to describe the technology as well as the dynamic behaviour of measuring spark plugs and to present the current state of technology. (orig.)

  7. DeepSpark: A Spark-Based Distributed Deep Learning Framework for Commodity Clusters

    OpenAIRE

    Kim, Hanjoo; Park, Jaehong; Jang, Jaehee; Yoon, Sungroh

    2016-01-01

    The increasing complexity of deep neural networks (DNNs) has made it challenging to exploit existing large-scale data processing pipelines for handling massive data and parameters involved in DNN training. Distributed computing platforms and GPGPU-based acceleration provide a mainstream solution to this computational challenge. In this paper, we propose DeepSpark, a distributed and parallel deep learning framework that exploits Apache Spark on commodity clusters. To support parallel operation...

  8. Cloud chamber researches in nuclear physics and cosmic radiation

    International Nuclear Information System (INIS)

    Blackett, P.

    1984-01-01

    An extract from Blackett's Nobel Prize speech of 1948, this recounts the work done by the author on particle tracks in a Wilson cloud chamber in 1932 at the Cavendish Laboratory, Cambridge. In particular he studied the energetic particles in cosmic rays using a cloud chamber and camera. The improvements to the equipment are recounted and photographs of cosmic ray showers taken with it are shown. (UK)

  9. Glove box chamber

    International Nuclear Information System (INIS)

    Cox, M.E.; Cox, M.E.

    1975-01-01

    An environmental chamber is described which enables an operator's hands to have direct access within the chamber without compromising a special atmosphere within such chamber. A pair of sleeves of a flexible material are sealed to the chamber around associated access apertures and project outwardly from such chamber. Each aperture is closed by a door which is openable from within the sleeve associated therewith so that upon an operator inserting his hand and arm through the sleeve, the operator can open the door to have access to the interior of the chamber. A container which is selectively separable from the remainder of the chamber is also provided to allow objects to be transferred from the chamber without such objects having to pass through the ambient atmosphere. An antechamber permitting objects to be passed directly into the chamber from the ambient atmosphere is included. (auth)

  10. Electro photographic materials

    International Nuclear Information System (INIS)

    Buzdugan, A.; Andries, A.; Iovu, M.

    2000-01-01

    The invention relates to the creation of electro photographic materials . The invention allows to extend the material photosensitivity into the infrared range of the spectrum. An electro photographic materials contains an electro conducting base, including a dielectric base 1, for example glass, an electro conducting layer 2, for example of Al, Ni, Cr, an injecting layer 3, consisting of amorphous indium phosphide, a vitreous layer 4 of the arsenic sulphide - antimony sulphide system and a transporting layer 5 of the arsenic sulphide or arsenic selenide

  11. Trace amount analysis using spark mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, Rene

    1975-01-01

    Characteristics of spark mass spectrometers (ion source, properties of the ion beam, ion optics, and performance) and their use in qualitative and quantitative analysis are described. This technique is very interesting for the semi-quantitative analysis of trace amounts, down to 10 -8 atoms. Examples of applications such as the analysis of high purity materials and non-conducting mineral samples, and determination of carbon and gas trace amounts are presented. (50 references) [fr

  12. Neutron bursts from long laboratory sparks

    Science.gov (United States)

    Kochkin, P.; Lehtinen, N. G.; Montanya, J.; Van Deursen, A.; Ostgaard, N.

    2016-12-01

    Neutron emission in association with thunderstorms and lightning discharges was reported by different investigators from ground-based observation platforms. In both cases such emission is explained by photonuclear reaction, since high-energy gamma-rays in sufficient fluxes are routinely detected from both, lightning and thunderclouds. The required gamma-rays are presumably generated by high-energy electrons in Bremsstrahlung process after their acceleration via cold and/or relativistic runaway mechanisms. This phenomenon attracted moderate scientific attention until fast neutron bursts (up to 10 MeV) from long 1 MV laboratory sparks have been reported. Clearly, with such relatively low applied voltage the electrons are unable to accelerate to the energies required for photo/electro disintegration. Moreover, all known elementary neutron generation processes are not capable to explain this emission right away. We performed an independent laboratory experiment on long sparks with the aim to confirm or disprove the neutron emission from them. The experimental setup was assembled at High-Voltage Laboratory in Barcelona and contained a Marx generator in a cone-cone spark gap configuration. The applied voltage was as low as 800 kV and the gap distance was only 60 cm. Two ns-fast cameras were located near the gap capturing short-exposure images of the pre-breakdown phenomenon at the expected neutron generation time. A plastic scintillation detector sensitive to neutrons was covered in 11 cm of lead and placed near the spark gap. The detector was calibrated and showed good performance in neutron detection. Apart of it, voltage, currents through both electrodes, and three X-ray detectors were also monitored in sophisticated measuring system. We will give an overview of the previous experimental and theoretical work in this topic, and present the results of our new experimental campaign. The conclusions are based on good signal-to-noise ratio measurements and are

  13. SPARK Version 1.1 user manual

    International Nuclear Information System (INIS)

    Weissenburger, D.W.

    1988-01-01

    This manual describes the input required to use Version 1.1 of the SPARK computer code. SPARK 1.1 is a library of FORTRAN main programs and subprograms designed to calculate eddy currents on conducting surfaces where current flow is assumed zero in the direction normal to the surface. Surfaces are modeled with triangular and/or quadrilateral elements. Lorentz forces produced by the interaction of eddy currents with background magnetic fields can be output at element nodes in a form compatible with most structural analysis codes. In addition, magnetic fields due to eddy currents can be determined at points off the surface. Version 1.1 features eddy current streamline plotting with optional hidden-surface-removal graphics and topological enhancements that allow essentially any orientable surface to be modeled. SPARK also has extensive symmetry specification options. In order to make the manual as self-contained as possible, six appendices are included that present summaries of the symmetry options, topological options, coil options and code algorithms, with input and output examples. An edition of SPARK 1.1 is available on the Cray computers at the National Magnetic Fusion Energy Computer Center at Livermore, California. Another more generic edition is operational on the VAX computers at the Princeton Plasma Physics Laboratory and is available on magnetic tape by request. The generic edition requires either the GKS or PLOT10 graphics package and the IMSL or NAG mathematical package. Requests from outside the United States will be subject to applicable federal regulations regarding dissemination of computer programs. 22 refs

  14. SPARK Version 1. 1 user manual

    Energy Technology Data Exchange (ETDEWEB)

    Weissenburger, D.W.

    1988-01-01

    This manual describes the input required to use Version 1.1 of the SPARK computer code. SPARK 1.1 is a library of FORTRAN main programs and subprograms designed to calculate eddy currents on conducting surfaces where current flow is assumed zero in the direction normal to the surface. Surfaces are modeled with triangular and/or quadrilateral elements. Lorentz forces produced by the interaction of eddy currents with background magnetic fields can be output at element nodes in a form compatible with most structural analysis codes. In addition, magnetic fields due to eddy currents can be determined at points off the surface. Version 1.1 features eddy current streamline plotting with optional hidden-surface-removal graphics and topological enhancements that allow essentially any orientable surface to be modeled. SPARK also has extensive symmetry specification options. In order to make the manual as self-contained as possible, six appendices are included that present summaries of the symmetry options, topological options, coil options and code algorithms, with input and output examples. An edition of SPARK 1.1 is available on the Cray computers at the National Magnetic Fusion Energy Computer Center at Livermore, California. Another more generic edition is operational on the VAX computers at the Princeton Plasma Physics Laboratory and is available on magnetic tape by request. The generic edition requires either the GKS or PLOT10 graphics package and the IMSL or NAG mathematical package. Requests from outside the United States will be subject to applicable federal regulations regarding dissemination of computer programs. 22 refs.

  15. Spark plasma sintering of tantalum carbide

    International Nuclear Information System (INIS)

    Khaleghi, Evan; Lin, Yen-Shan; Meyers, Marc A.; Olevsky, Eugene A.

    2010-01-01

    A tantalum carbide powder was consolidated by spark plasma sintering. The specimens were processed under various temperature and pressure conditions and characterized in terms of relative density, grain size, rupture strength and hardness. The results are compared to hot pressing conducted under similar settings. It is shown that high densification is accompanied by substantial grain growth. Carbon nanotubes were added to mitigate grain growth; however, while increasing specimens' rupture strength and final density, they had little effect on grain growth.

  16. Does Taking Photographs Help?

    Science.gov (United States)

    Hand, Sarah

    2010-01-01

    Since many people tend to use photographs as memory anchors, this author decided she wanted to know whether the process of capturing and manipulating an image taken during a learning activity would act as a memory anchor for children's visual, auditory and kinaesthetic memories linked to their cognitive learning at the time. In plain English,…

  17. Dual ionization chamber

    International Nuclear Information System (INIS)

    Mallory, J.; Turlej, Z.

    1981-01-01

    Dual ionization chambers are provided for use with an electronic smoke detector. The chambers are separated by electrically-conductive partition. A single radiation source extends through the partition into both chambers, ionizing the air in each. The mid-point current of the device may be balanced by adjusting the position of the source

  18. 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.

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

    International Nuclear Information System (INIS)

    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

  20. Geotagging Photographs in Student Fieldwork

    Science.gov (United States)

    Welsh, Katharine E.; France, Derek; Whalley, W. Brian; Park, Julian R.

    2012-01-01

    This resource paper provides guidance for staff and students on the potential educational benefits, limitations and applications of geotagging photographs. It also offers practical advice for geotagging photographs in a range of fieldwork settings and reviews three free smartphone applications (apps) for geotagging photographs (Flickr, Evernote…

  1. Double chamber ion source

    International Nuclear Information System (INIS)

    Uman, M.F.; Winnard, J.R.; Winters, H.F.

    1978-01-01

    The ion source is comprised of two discharge chambers one of which is provided with a filament and an aperture leading into the other chamber which in turn has an extraction orifice. A low voltage arc discharge is operated in an inert gas atmosphere in the filament chamber while an arc of higher voltage is operated in the second ionization chamber which contains a vapor which will give the desired dopant ion species. The entire source is immersed in an axial magnetic field parallel to a line connecting the filament, the aperture between the two chambers and the extraction orifice. (author)

  2. Big Data Analytics with Datalog Queries on Spark.

    Science.gov (United States)

    Shkapsky, Alexander; Yang, Mohan; Interlandi, Matteo; Chiu, Hsuan; Condie, Tyson; Zaniolo, Carlo

    2016-01-01

    There is great interest in exploiting the opportunity provided by cloud computing platforms for large-scale analytics. Among these platforms, Apache Spark is growing in popularity for machine learning and graph analytics. Developing efficient complex analytics in Spark requires deep understanding of both the algorithm at hand and the Spark API or subsystem APIs (e.g., Spark SQL, GraphX). Our BigDatalog system addresses the problem by providing concise declarative specification of complex queries amenable to efficient evaluation. Towards this goal, we propose compilation and optimization techniques that tackle the important problem of efficiently supporting recursion in Spark. We perform an experimental comparison with other state-of-the-art large-scale Datalog systems and verify the efficacy of our techniques and effectiveness of Spark in supporting Datalog-based analytics.

  3. Studies of particle interactions in bubble chamber, spark chambers and counter experiments: Task P. Annual progress report

    International Nuclear Information System (INIS)

    Jones, L.M.; Holloway, L.; O'Halloran, T.A. Jr.; Simmons, R.O.

    1983-07-01

    Our current work reflects the general aim of this task, which is to calculate phenomenological theories of interest to present experiments. Recently, this has emphasized the jet calculus approach to properties of quark and gluon jets. Progress is reviewed

  4. Photograph of the Month

    Science.gov (United States)

    2015-04-01

    For dykes, magma flow direction can be deciphered from various fabrics in the chilled margin (Correa-Gomez et al., 2001, JSG 23, 1415). This photograph represents part of a chilled margin of a appr. N- S trending dyke at Kharghar Hills, Mumbai, Maharashtra, India. The section is sub-vertical. The elongated grooves indicate flow of magma through a fault and the tapered grooves (arrows) connote the flow direction: towards the pointed end of the groove. The magma flowed towards the north in this case. Such fabrics of wall-magma interaction in the Deccan volcanic province prove that dykes injected along fault planes. 19° 2‧ 22.3″ N, 73° 3‧ 28.7″ E. Photograph Ayan Achyuta Misra, Mumbai, India.

  5. Liquid-Arc/Spark-Excitation Atomic-Emission Spectroscopy

    Science.gov (United States)

    Schlagen, Kenneth J.

    1992-01-01

    Constituents of solutions identified in situ. Liquid-arc/spark-excitation atomic-emission spectroscopy (LAES) is experimental variant of atomic-emission spectroscopy in which electric arc or spark established in liquid and spectrum of light from arc or spark analyzed to identify chemical elements in liquid. Observations encourage development of LAES equipment for online monitoring of process streams in such industries as metal plating, electronics, and steel, and for online monitoring of streams affecting environment.

  6. Computer aided photographic engineering

    Science.gov (United States)

    Hixson, Jeffrey A.; Rieckhoff, Tom

    1988-01-01

    High speed photography is an excellent source of engineering data but only provides a two-dimensional representation of a three-dimensional event. Multiple cameras can be used to provide data for the third dimension but camera locations are not always available. A solution to this problem is to overlay three-dimensional CAD/CAM models of the hardware being tested onto a film or photographic image, allowing the engineer to measure surface distances, relative motions between components, and surface variations.

  7. Development of a SPARK Training Dataset

    International Nuclear Information System (INIS)

    Sayre, Amanda M.; Olson, Jarrod R.

    2015-01-01

    In its first five years, the National Nuclear Security Administration's (NNSA) Next Generation Safeguards Initiative (NGSI) sponsored more than 400 undergraduate, graduate, and post-doctoral students in internships and research positions (Wyse 2012). In the past seven years, the NGSI program has, and continues to produce a large body of scientific, technical, and policy work in targeted core safeguards capabilities and human capital development activities. Not only does the NGSI program carry out activities across multiple disciplines, but also across all U.S. Department of Energy (DOE)/NNSA locations in the United States. However, products are not readily shared among disciplines and across locations, nor are they archived in a comprehensive library. Rather, knowledge of NGSI-produced literature is localized to the researchers, clients, and internal laboratory/facility publication systems such as the Electronic Records and Information Capture Architecture (ERICA) at the Pacific Northwest National Laboratory (PNNL). There is also no incorporated way of analyzing existing NGSI literature to determine whether the larger NGSI program is achieving its core safeguards capabilities and activities. A complete library of NGSI literature could prove beneficial to a cohesive, sustainable, and more economical NGSI program. The Safeguards Platform for Automated Retrieval of Knowledge (SPARK) has been developed to be a knowledge storage, retrieval, and analysis capability to capture safeguards knowledge to exist beyond the lifespan of NGSI. During the development process, it was necessary to build a SPARK training dataset (a corpus of documents) for initial entry into the system and for demonstration purposes. We manipulated these data to gain new information about the breadth of NGSI publications, and they evaluated the science-policy interface at PNNL as a practical demonstration of SPARK's intended analysis capability. The analysis demonstration sought to answer

  8. Development of micromegas muon chambers for the ATLAS upgrade

    Science.gov (United States)

    Wotschack, J.

    2012-02-01

    Large-area particle detectors based on the bulk-micromegas technology are an attractive choice for the upgrade of LHC detectors and/or detectors for the ILC or other experiments. In the context of the R&D for the ATLAS Muon System upgrade, we have built detectors of order 1 m2. In order to overcome the spark problem in micromegas a novel protection scheme using resistive strips above the readout electrode has been developed. This technology has undergone extensive tests with hadron beams at the CERN-SPS, X-rays in the lab, as well as in a neutron beam. In addition, four 10 × 10 cm2 micromegas chambers have been installed in the ATLAS cavern and are taking data under LHC conditions. We will discuss the underlying design of the chambers and present results on the performance of these chambers.

  9. Development of micromegas muon chambers for the ATLAS upgrade

    International Nuclear Information System (INIS)

    Wotschack, J

    2012-01-01

    Large-area particle detectors based on the bulk-micromegas technology are an attractive choice for the upgrade of LHC detectors and/or detectors for the ILC or other experiments. In the context of the R and D for the ATLAS Muon System upgrade, we have built detectors of order 1 m 2 . In order to overcome the spark problem in micromegas a novel protection scheme using resistive strips above the readout electrode has been developed. This technology has undergone extensive tests with hadron beams at the CERN-SPS, X-rays in the lab, as well as in a neutron beam. In addition, four 10 × 10 cm 2 micromegas chambers have been installed in the ATLAS cavern and are taking data under LHC conditions. We will discuss the underlying design of the chambers and present results on the performance of these chambers.

  10. Hybrid employment recommendation algorithm based on Spark

    Science.gov (United States)

    Li, Zuoquan; Lin, Yubei; Zhang, Xingming

    2017-08-01

    Aiming at the real-time application of collaborative filtering employment recommendation algorithm (CF), a clustering collaborative filtering recommendation algorithm (CCF) is developed, which applies hierarchical clustering to CF and narrows the query range of neighbour items. In addition, to solve the cold-start problem of content-based recommendation algorithm (CB), a content-based algorithm with users’ information (CBUI) is introduced for job recommendation. Furthermore, a hybrid recommendation algorithm (HRA) which combines CCF and CBUI algorithms is proposed, and implemented on Spark platform. The experimental results show that HRA can overcome the problems of cold start and data sparsity, and achieve good recommendation accuracy and scalability for employment recommendation.

  11. Sparking investment in Ontario's power generation industry

    International Nuclear Information System (INIS)

    Allen, J.

    2004-01-01

    This paper discusses the business strategy needed to spark investment in Ontario's power generation industry. It examines the process of decision making and investing in an uncertain environment. The paper suggests that any strategy based on one view of the future courts trouble and that strategic flexibility can prepare for what cannot be predicted. Finally the paper suggests that Ontario needs to create a stable policy and regulatory environment that allows investors to fulfill reasonable expectations and investors need to place bets that provide the flexibility to respond quickly to changing market conditions

  12. Anticipating Change, Sparking Innovation: Framing the Future

    Science.gov (United States)

    Finnegan, John R.; Spencer, Harrison C.

    2015-01-01

    As the 100th anniversary of the 1915 Welch-Rose report approaches, the Association of Schools and Programs of Public Health (ASPPH) has been pursuing two initiatives to spark innovation in academic partnerships for enhancing population health: (1) Framing the Future: The Second 100 Years of Education for Public Health and (2) Reconnecting Public Health and Care Delivery to Improve the Health of Populations. We describe how ASPPH-member schools and programs accredited by the Council on Education for Public Health, along with their extraordinarily diverse array of partners, are working to improve education that better prepares health professionals to meet 21st-century population health needs. PMID:25706017

  13. Development of a Micro Pixel Chamber for the ATLAS Upgrade

    CERN Document Server

    Ochi, Atsuhiko; Komai, Hidetoshi; Edo, Yuki; Yamaguchi, Takahiro

    2012-01-01

    The Micro Pixel Chamber (μ-PIC) is being developed a sacandidate for the muon system of the ATLAS detector for upgrading in LHC experiments. The μ-PIC is a micro-pattern gaseous detector that doesn’t have floating structure such as wires, mesh, or foil. This detector can be made by printed-circuit-board (PCB) technology, which is commercially available and suited for mass production. Operation tests have been performed under high flux neutrons under similar conditions to the ATLAS cavern. Spark rates are measured using several gas mixtures under 7 MeV neutron irradiation, and good properties were observed using neon, ethane, and CF4 mixture of gases.Using resistive materials as electrodes, we are also developing a new μ-PIC, which is not expected to damage the electrodes in the case of discharge sparks.

  14. 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.

  15. 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

  16. Silicon nanoparticles produced by spark discharge

    International Nuclear Information System (INIS)

    Vons, Vincent A.; Smet, Louis C. P. M. de; Munao, David; Evirgen, Alper; Kelder, Erik M.; Schmidt-Ott, Andreas

    2011-01-01

    On the example of silicon, the production of nanoparticles using spark discharge is shown to be feasible for semiconductors. The discharge circuit is modelled as a damped oscillator circuit. This analysis reveals that the electrode resistance should be kept low enough to limit energy loss by Joule heating and to enable effective nanoparticle production. The use of doped electrodes results in a thousand-fold increase in the mass production rate as compared to intrinsic silicon. Pure and oxidised uniformly sized silicon nanoparticles with a primary particle diameter of 3–5 nm are produced. It is shown that the colour of the particles can be used as a good indicator of the oxidation state. If oxygen and water are banned from the spark generation system by (a) gas purification, (b) outgassing and (c) by initially using the particles produced as getters, unoxidised Si particles are obtained. They exhibit pyrophoric behaviour. This continuous nanoparticle preparation method can be combined with other processing techniques, including surface functionalization or the immediate impaction of freshly prepared nanoparticles onto a substrate for applications in the field of batteries, hydrogen storage or sensors.

  17. Power source with spark-safe outlet

    Energy Technology Data Exchange (ETDEWEB)

    Tsesarenko, N P; Alekhin, A V

    1982-01-01

    The invention refers to the technique of electrical monitoring and control in systems operating in a spark-safe medium (for example, in coal mines). A more accurate area of application is mobile objects with autonomous source of electricity (mine diesel locomotives, battery electric locomotives etc.). The purpose of the invention is to simplify and to improve the reliability of the planned device, and also to expand the area of application for conditions when it is powered from an autonomous generator of direct voltage. This goal is achieved because the power source with spark-safe outlet (the source contains a thyristor of advance disconnection, connected by anode to the delimiting throttle, one outlet of which is connected to the capacitor included between the controlling electrode and the anode of the thyristor, and the capacitor is connected through the resistor parallel to the outlet clamps of the source, while the thyristor of emergency protection connected parallel to the inlet clamps of the power source) is additionally equipped with a current sensor, hercon, transistor key (included in series in the power circuit) and optron, whose emitter is connected parallel to the current sensor connected in series to the inlet of the power source, while the receiver of the optron is connected in a circuit for controlling the thyristor of emergency protection. Hercon is built into the core of the delimiting throttle and is connected to the circuit for controlling the transistor key.

  18. 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...

  19. Gas microstrip chambers

    International Nuclear Information System (INIS)

    McIntyre, P.M.; Barasch, E.F.; Bowcock, T.J.V.; Demroff, H.P.; Elliott, S.M.; Howe, M.R.; Lee, B.; Mazumdar, T.K.; Pang, Y.; Smith, D.D.; Wahl, J.; Wu, Y.; Yue, W.K.; Gaedke, R.M.; Vanstraelen, G.

    1992-01-01

    The gas microstrip chamber has been developed from concept to experimental system during the past three years. A pattern of anode and grid lines are microfabricated onto a dielectric substrate and configured as a high-resolution MWPC. Four recent developments are described: Suitable plastic substrates and lithography techniques for large-area chambers; non-planar silicon-based chambers for 20 μm resolution; integrated on-board synchronous front-end electronics and data buffering; and a porous silicon active cathode for enhanced efficiency and time response. The microstrip chamber appears to be a promising technology for applications in microvertex, tracking spectrometer, muon spectrometer, and transition radiation detection. (orig.)

  20. Vehicle driving cycle performance of the spark-less di-ji hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box663, Ballarat, VIC 3353 (Australia)

    2010-05-15

    The paper describes coupled CFD combustion simulations and CAE engine performance computations to describe the operation over the full range of load and speed of an always lean burn, Direct Injection Jet Ignition (DI-JI) hydrogen engine. Jet ignition pre-chambers and direct injection are enablers of high efficiencies and load control by quantity of fuel injected. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the spark-less pre-chamber of the DI-JI engine, where it mixes with the air entering from the main chamber and auto-ignites because of the high temperature of the hot glow plug. Then, jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. Engine maps of brake specific fuel consumption vs. speed and brake mean effective pressure are computed first. CAE vehicle simulations are finally performed evaluating the fuel consumption over emission cycles of a vehicle equipped with this engine. (author)

  1. Development of a SPARK Training Dataset

    Energy Technology Data Exchange (ETDEWEB)

    Sayre, Amanda M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Olson, Jarrod R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-01

    In its first five years, the National Nuclear Security Administration’s (NNSA) Next Generation Safeguards Initiative (NGSI) sponsored more than 400 undergraduate, graduate, and post-doctoral students in internships and research positions (Wyse 2012). In the past seven years, the NGSI program has, and continues to produce a large body of scientific, technical, and policy work in targeted core safeguards capabilities and human capital development activities. Not only does the NGSI program carry out activities across multiple disciplines, but also across all U.S. Department of Energy (DOE)/NNSA locations in the United States. However, products are not readily shared among disciplines and across locations, nor are they archived in a comprehensive library. Rather, knowledge of NGSI-produced literature is localized to the researchers, clients, and internal laboratory/facility publication systems such as the Electronic Records and Information Capture Architecture (ERICA) at the Pacific Northwest National Laboratory (PNNL). There is also no incorporated way of analyzing existing NGSI literature to determine whether the larger NGSI program is achieving its core safeguards capabilities and activities. A complete library of NGSI literature could prove beneficial to a cohesive, sustainable, and more economical NGSI program. The Safeguards Platform for Automated Retrieval of Knowledge (SPARK) has been developed to be a knowledge storage, retrieval, and analysis capability to capture safeguards knowledge to exist beyond the lifespan of NGSI. During the development process, it was necessary to build a SPARK training dataset (a corpus of documents) for initial entry into the system and for demonstration purposes. We manipulated these data to gain new information about the breadth of NGSI publications, and they evaluated the science-policy interface at PNNL as a practical demonstration of SPARK’s intended analysis capability. The analysis demonstration sought to answer the

  2. Combustion and operating characteristics of spark-ignition engines

    Science.gov (United States)

    Heywood, J. B.; Keck, J. C.; Beretta, G. P.; Watts, P. A.

    1980-01-01

    The spark-ignition engine turbulent flame propagation process was investigated. Then, using a spark-ignition engine cycle simulation and combustion model, the impact of turbocharging and heat transfer variations or engine power, efficiency, and NO sub x emissions was examined.

  3. Dual Spark Plugs For Stratified-Charge Rotary Engine

    Science.gov (United States)

    Abraham, John; Bracco, Frediano V.

    1996-01-01

    Fuel efficiency of stratified-charge, rotary, internal-combustion engine increased by improved design featuring dual spark plugs. Second spark plug ignites fuel on upstream side of main fuel injector; enabling faster burning and more nearly complete utilization of fuel.

  4. On the occurrence of ‘bead lightning’ phenomena in long laboratory sparks

    Energy Technology Data Exchange (ETDEWEB)

    Vayanganie, S.P.A., E-mail: amilavayanganie@gmail.com [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka); Cooray, V.; Rahman, Mahbubur; Hettiarachchi, Pasan; Diaz, Oscar [Lightning Research Group, The Ångström Laboratory Division of Electricity, Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Fernando, M. [Atmospheric Physics and Lightning Research Group, University of Colombo, Colombo 03 (Sri Lanka)

    2016-02-22

    The formation of bead lightning, where the lightning channel appears to break up into luminous fragments, is still an object of speculation. Here we report similar observations in laboratory discharges. Analysis of time resolved photographs shows that the discharge channel exhibits a ‘bead pattern’ in the decaying stage of the discharge and the occurrence of loops in the channel sections where the bead pattern is observed. This result presents the first evidence that the rapid cooling of non-uniform channel sections could lead to the formation of beads. It is suggested that periodically occurring non-uniform channel sections could explain the bead pattern of lightning discharges. - Highlights: • For the first time, the occurrence of bead patterns in the channel of laboratory sparks was reported. • Depending on the geometry some regions of the channel decays faster than the other sections. • A possible mechanism for the occurrence of beads in decaying states of lightning flashes is proposed.

  5. Protection of neutral-beam accelerator electrodes from spark discharges

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1977-01-01

    The high-voltage (HV) electrodes of neutral beam sources (NBS's) must be protected from occasional sparks to ground. Spark currents can be limited with special transformers and reactors which introduce time delays that are long enough to quench the spark or to disconnect the energy source. A saturated time delay transformer (STDT) connected in series with the HV power supply detects spark faults and limits the current supplied by the power supply and its capacitance to ground; it also initiates spark quenching. Nonsaturated, longitudinal reactors limit the discharge current supplied by the energy stored in the circuit capacitance of the NBS filament and arc power supplies long enough to discharge this capacitance into a resistor. The design principles of these protective circuits are presented

  6. Protection of neutral-beam-accelerator electrodes from spark discharges

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1977-01-01

    The high-voltage (HV) electrodes of neutral beam sources (NBS's) must be protected from occasional sparks to ground. Spark currents can be limited with special transformers and reactors which introduce time delays that are long enough to quench the spark or to disconnect the energy source. A saturated time delay transformer (STDT) connected in series with the HV power supply detects spark faults and limits the current supplied by the power supply and its capacitance to ground; it also initiates spark quenching. Nonsaturated, longitudinal reactors limit the discharge current supplied by the energy stored in the circuit capacitance of the NBS filament and arc power supplies long enough to discharge this capacitance into a resistor. The design principles of these protective circuits are presented in this paper

  7. Protection of neutral-beam-accelerator electrodes from spark discharges

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1978-01-01

    The high-voltage (HV) electrodes of neutral beam sources (NBS's) must be protected from occasional sparks to ground. Spark currents can be limited with special transformers and reactors which introduce time delays that are long enough to quench the spark or to disconnect the energy source. A saturated time delay transformer (STDT) connected in series with the HV power supply detects spark faults and limits the current supplied by the power supply and its capacitance to ground; it also initiates spark quenching. Nonsaturated, longitudinal reactors limit the discharge current supplied by the energy stored in the circuit capacitance of the NBS filament and arc power supplies long enough to discharge this capacitance into a resistor. The design principles of these protective circuits are presented in this paper

  8. Photographic Tourism Research: Literature Review

    OpenAIRE

    Virdee, Inderpal

    2017-01-01

    This study reviews the current photographic tourism literature to identify what fields within tourism have been studied by researchers, the contexts, the samples used, the sampling methods employed, the photographic methods and supporting methods used, the data analysis techniques applied and the countries studied. A set of 115 relevant academic articles were selected and assessed using content analysis. The findings showed that overall publications in the field of photographic tourism increa...

  9. The Life of Digital Photographs

    DEFF Research Database (Denmark)

    Larsen, Jonas

    )mobilities of things, practice approaches to photography and multi sited ethnography, this talk discusses and empirically track the life (the conception, birth, transformative years, ageing and death) travel, detours, makeovers and destinations of (analogue and digital) photographs in our present network societies. So...... we can understand the life of more-than representational photographs, and then I turn to my ethnographies to flesh out empirically the life of tourist photographs...

  10. An electrodeless drift chamber

    International Nuclear Information System (INIS)

    Allison, J.; Barlow, R.J.; Bowdery, C.K.; Duerdoth, I.; Rowe, P.G.

    1982-01-01

    We describe a chamber in which the drift field is controlled by the deposition of electrostatic charge on an insulating surface. The chamber operates with good efficiency and precision for observed drift distances of up to 45 cm, promises to be extremely robust and adaptable and offers a very cheap way of making particle detectors. (orig.)

  11. High resolution drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  12. Plastic flashtube chambers

    International Nuclear Information System (INIS)

    Frisken, W.R.

    1977-01-01

    A brief discussion is given of the use and operation of plastic flashtube chambers. Gas leaks, electric pulsing, the glow discharge, and readout methods are considered. Three distinct problems with high rate applications deal with resolving time, dead time, and polarization/neutralization of the chamber

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. Pseudo-spark switch (PSS) characteristics under different operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, B. H., E-mail: dr.bassmahussain@gmail.com; Ahmad, A. K., E-mail: ahmad.kamal@sc.nahrainuniv.edu.iq [College of Science, Al Nahrain University, Jadria, Baghdad (Iraq); Lateef, K. H., E-mail: kamalhlatif@yahoo.com [Ministry of Science and Technology, Jadria, Baghdad (Iraq)

    2016-08-15

    The present paper concentrates on the characteristics of the pseudospark switch (PSS) designed in a previous work. The special characteristics of PSS make it a replacement for other high voltage switches such as thyratrons and ordinary high-pressure spark gaps. PSS is characterized by short rise time and small jitter time. The pseudo park chamber consists of two hollow cylindrical electrodes made of a stainless steel material (type 306L) separated by an insulator. The insulator used in our design is a glazed ceramic 70 mm in diameter and 3.5 mm in thickness. A PSS with an anode voltage of 29.2 kV, and a current of 3.6 kA and 11 ns rise time was achieved and used successfully at a repetition rate of about 2.2 kHz. A simple trigger circuit designed, built, and used effectively reaching more than 1.56 kV trigger pulse which is sufficient to ignite the argon gas inside the cathode to cause a breakdown. A non-inductive dummy load is designed to be a new technique to find the accurate value of the PSS inductance. A jitter time of ±10 ns pulses is observed to occur in a reliable manner for more than 6 h of continuous operation. In this research, the important parameters of this switch like rise time, peak current, and anode voltage were studied at various values of charging capacitance. The lifetime of this system is depending on the kind of the electrode material and on the type of insulation material in the main gap of the pseudospark switch.

  18. A spectroscopy study of gasoline partially premixed compression ignition spark assisted combustion

    International Nuclear Information System (INIS)

    Pastor, J.V.; García-Oliver, J.M.; García, A.; Micó, C.; Durrett, R.

    2013-01-01

    Highlights: ► PPC combustion combined with spark assistance and gasoline fuel on a CI engine. ► Chemiluminescence of different chemical species describes the progress of combustion reaction. ► Spectra of a novel combustion mode under SACI conditions is described. ► UV–Visible spectrometry, high speed imaging and pressure diagnostic were employed for analysis. - Abstract: Nowadays many research efforts are focused on the study and development of new combustion modes, mainly based on the use of locally lean air–fuel mixtures. This characteristic, combined with exhaust gas recirculation, provides low combustion temperatures that reduces pollutant formation and increases efficiency. However these combustion concepts have some drawbacks, related to combustion phasing control, which must be overcome. In this way, the use of a spark plug has shown to be a good solution to improve phasing control in combination with lean low temperature combustion. Its performance is well reported on bibliography, however phenomena involving the combustion process are not completely described. The aim of the present work is to develop a detailed description of the spark assisted compression ignition mode by means of application of UV–Visible spectrometry, in order to improve insight on the combustion process. Tests have been performed in an optical engine by means of broadband radiation imaging and emission spectrometry. The engine hardware is typical of a compression ignition passenger car application. Gasoline was used as the fuel due to its low reactivity. Combining broadband luminosity images with pressure-derived heat-release rate and UV–Visible spectra, it was possible to identify different stages of the combustion reaction. After the spark discharge, a first flame kernel appears and starts growing as a premixed flame front, characterized by a low and constant heat-release rate in combination with the presence of remarkable OH radical radiation. Heat release increases

  19. Photographic Portraits: Narrative and Memory

    Directory of Open Access Journals (Sweden)

    Brian Roberts

    2011-05-01

    Full Text Available This article is a more general "companion" to the subsequent, Brian ROBERTS (2011 "Interpreting Photographic Portraits: Autobiography, Time Perspectives and Two School Photographs". The article seeks to add to the growing awareness of the importance of visual materials and methods in qualitative social research and to give an introduction to the "photographic self image"—self-portraits and portraits. It focuses on time and memory, including the experiential associations (in consciousness and the senses that the self engenders, thus linking the "visual" (photographic and "auto/biographical". The article attempts to "map" a field—the use of portraiture within social science—drawing on narrative and biographical research, on one side, and photographic portraiture, on the other. In supporting the use of photography in qualitative research it points to the need for researchers to have a greater knowledge of photographic (and art criticism and cognisance of photographic practices. The article does not intend to give a definitive account of photographic portraiture or prescribe in detail how it may be used within social science. It is an initial overview of the development and issues within the area of photographic portraiture and an exploration of relevant methodological issues when images of individuals are employed within social science—so that "portraiture" is better understood and developed within biographical and narrative research. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs110263

  20. Aperture and counting rate of rectangular telescopes for single and multiple parallel particles. [Spark chamber telescopes

    Energy Technology Data Exchange (ETDEWEB)

    D' Ettorre Piazzoli, B; Mannocchi, G [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Melone, S [Istituto di Fisica dell' Universita, Ancona, Italy; Picchi, P; Visentin, R [Comitato Nazionale per l' Energia Nucleare, Frascati (Italy). Laboratori Nazionali di Frascati

    1976-06-01

    Expressions for the counting rate of rectangular telescopes in the case of single as well as multiple particles are given. The aperture for single particles is obtained in the form of a double integral and analytical solutions are given for some cases. The intensity for different multiplicities of parallel particles is related to the geometry of the detectors and to the features of the radiation. This allows an absolute comparison between the data recorded by different devices.

  1. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber

    KAUST Repository

    Wolk, Benjamin; DeFilippo, Anthony; Chen, Jyh-Yuan; Dibble, Robert; Nishiyama, Atsushi; Ikeda, Yuji

    2013-01-01

    -thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure

  2. Psub(T) analysis of multicored EAS observed by the 54m2 spark chamber

    International Nuclear Information System (INIS)

    Yamamoto, Y.; Nakatsuka, T.; Kawamoto, M.

    1982-01-01

    Rate of subcores whose axes traversed iron beams was examined by the precise measurement of air shower's arrival direction and subcore's location. As a result, it is estimated that 72,5% of subcores we picked up are from atmospheric origin and 27.5% are from iron beam origin. Psub(T) spectrum of atmospheric origin subcores made from 63 subcores (36.6%) not traversing iron beams is a little (factor = 0.7) lower than that of all subcores but alike in the slope. The cross section of large-Psub(T)-jet generating such subcores is still very large and comparable to the estimation by Cline applying QCD to large-Psub(T)-jet

  3. Method of making stepped photographic density standards of radiographic photographs

    International Nuclear Information System (INIS)

    Borovin, I.V.; Kondina, M.A.

    1987-01-01

    In industrial radiography practice the need often arises for a prompt evaluation of the photographic density of an x-ray film. A method of making stepped photographic density standards for industrial radiography by contact printing from a negative is described. The method is intended for industrial radiation flaw detection laboratories not having specialized sensitometric equipment

  4. Nonlinear control of a spark ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Bidan, P [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Boverie, S; Chaumerliac, V [Siemens AutomotiveSA, MIRGAS Laboratory, 31 - Toulouse (France)

    1994-12-31

    This paper describes the improvements which can be made to spark ignition engine by extensive use of automatic control. Particular emphasis is placed on fast transient phases produced by simultaneous action on the throttle and the electronic fuel injection device. The aim is to achieve better performance for the fuel/air ratio regulation system, thereby improving engine efficiency and exhaust emission during these transient phases. The authors begin by presenting an average dynamic model of the intake manifold validated on an engine test bench and goes on to develop a closed-loop system controlling average pressure in the intake manifold using the reference tracking model method. The air supply control system is combined with a predictor to compensate for delays in the injection procedure. The paper concludes with a comparison between the results obtained using simulation and those obtained experimentally from the engine. (author) 10 refs.

  5. Spark-safe mechanical fluctuation sensor

    Energy Technology Data Exchange (ETDEWEB)

    Retek, S; Galisz, T

    1979-04-20

    The subject of the invention is a mechanical fluctuation sensor in a spark-safe design for use at mines which are dangerous for gas, as an element of different systems for remote control information transfer. The patented sensor of mechanical fluctuations contains: magnetic-induction transformer characterized by the fact that its inert mass consists of a plane permanent magnet placed in the suspended state on springs between 2 coils, which together with their cores are rigidly fixed to the walls of the ferromagnetic vessels. The ends of the coil windings are interconnected, while the beginnings of the windings are lead out with connection to the outlet of the electronic amplifier with binary outlet signal. The electronic amplifier is placed between the transformer in the common ferromagnetic housing which is a screen for protection from the effect of external magnetic fields.

  6. Investigation of gas discharge by schlieren method and interferometry with automated processing of schlieren photographs and interferograms

    International Nuclear Information System (INIS)

    Gerasimova, V.I.; Dushin, L.A.; Privezentsev, V.S.; Taran, V.S.

    1974-01-01

    The principles are clarified of two optical plasma diagnostics techniques, viz., the interferometric method permitting the determination of electron density and the schlieren method determining the gradient of electron density. Both techniques in combination were used in investigating the plasma in a hydrogen hollow-cathode spark discharge. In the schlieren technique, a pulsed xenon laser, in the interference technique a helium-neon laser were used as the light sources. Schlieren photographs were processed automatically using an electronic computer. A detailed description is presented of the equipment for the automatic photograph evaluation. (A.K.)

  7. OPAL Jet Chamber Prototype

    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 dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  8. 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.

  9. Target fabrication using laser and spark erosion machining

    International Nuclear Information System (INIS)

    Clement, X.; Coudeville, A.; Eyharts, P.; Perrine, J.P.; Rouillard, R.

    1982-01-01

    Fabrication of laser fusion targets requires a number of special techniques. We have developed both laser and spark erosion machining to produce minute parts of complex targets. A high repetition rate YAG laser at double frequency is used to etch various materials. For example, marks or patterns are often necessary on structured or advanced targets. The laser is also used to thin down plastic coated stalks. A spark erosion system has proved to be a versatile tool and we describe current fabrication processes like cutting, drilling, and ultra precise machining. Spark erosion has interesting features for target fabrication: it is a highly controllable and reproducible technique as well as relatively inexpensive

  10. Acoustic-Levitation Chamber

    Science.gov (United States)

    Barmatz, M. B.; Granett, D.; Lee, M. C.

    1984-01-01

    Uncontaminated environments for highly-pure material processing provided within completely sealed levitation chamber that suspends particles by acoustic excitation. Technique ideally suited for material processing in low gravity environment of space.

  11. 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).

  12. Miniature ionization chamber

    International Nuclear Information System (INIS)

    Alexeev, V.I.; Emelyanov, I.Y.; Ivanov, V.M.; Konstantinov, L.V.; Lysikov, B.V.; Postnikov, V.V.; Rybakov, J.V.

    1976-01-01

    A miniature ionization chamber having a gas-filled housing which accommodates a guard electrode made in the form of a hollow perforated cylinder is described. The cylinder is electrically associated with the intermediate coaxial conductor of a triaxial cable used as the lead-in of the ionization chamber. The gas-filled housing of the ionization chamber also accommodates a collecting electrode shaped as a rod electrically connected to the center conductor of the cable and to tubular members. The rod is disposed internally of the guard electrode and is electrically connected, by means of jumpers passing through the holes in the guard electrode, to the tubular members. The tubular members embrace the guard electrode and are spaced a certain distance apart along its entire length. Arranged intermediate of these tubular members are spacers secured to the guard electrode and fixing the collecting electrode throughout its length with respect to the housing of the ionization chamber

  13. Reference ionization chamber

    International Nuclear Information System (INIS)

    Golnik, N.; Zielczynski, M.

    1999-01-01

    The paper presents the design of ionization chamber devoted for the determination of the absolute value of the absorbed dose in tissue-equivalent material. The special attention was paid to ensure that the volume of the active gas cavity was constant and well known. A specific property of the chamber design is that the voltage insulators are 'invisible' from any point of the active volume. Such configuration ensures a very good time stability of the electrical field and defines the active volume. The active volume of the chamber was determined with accuracy of 0.3%. This resulted in accuracy of 0.8% in determination of the absorbed dose in the layer of material adherent to the gas cavity. The chamber was applied for calibration purposes at radiotherapy facility in Joint Institute for Nuclear Research in Dubna (Russia) and in the calibration laboratory of the Institute of Atomic Energy in Swierk. (author)

  14. Gridded ionization chamber

    International Nuclear Information System (INIS)

    Houston, J.M.

    1977-01-01

    An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltsge intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  15. 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.

  16. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

    Manero Amoros, F.

    1962-01-01

    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

  17. 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.

  18. Sleeve reaction chamber system

    Science.gov (United States)

    Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  19. [Cracow medical chamber in the special collection of the main medical library].

    Science.gov (United States)

    Szkudaj, T

    2000-01-01

    The article on Cracow Medical Chamber in the Special Collection of the Main Medical Library concerns the history of establishing medical chambers and covers the period from 1893 to 1950. It presents in detail the territorial extent of Cracow Medical Chamber, its membership and presidents' functions as well as the composition of its various boards and councils. It also talks about the legal acts regulating the functioning of medical chambers and their sphere of activity. The collection of archived records kept in the Special Collection of Main Medical Library constitutes a small percentage of the preserved records; these being mainly personal files of doctors comprising personal questionnaires, registration cards and photographs.

  20. A new gaseous detector for tracking: The blade chamber

    International Nuclear Information System (INIS)

    Ambrosi, G.; Battiston, R.; Levi, G.; Barillari, T.; Susinno, G.; Bergsma, F.; Contin, A.; Labbe, J.C.; Laurenti, G.; Mattern, D.; Simonet, G.; Williams, M.C.S.; Zichichi, A.; Boscherini, D.; Bruni, G.; De Pasquale, S.; Giusti, P.; Maccarrone, G.; Nania, R.; O'Shea, V.; Castro, H.; Galvez, J.; Rivera, F.; Schioppa, M.; Sharma, A.

    1990-01-01

    As part of the LAA project at CERN a prototype of a streamer-chamber in which a blade, instead of a wire, is used as the amplification electrode has been built. A big advantage is that the blade can be bent to follow a curve so that a chamber can be built with cells ideally matched to the geometry of the experiment. Moreover, a blade is very rugged, it can withstand severe mechanical shocks and it is also resistant to damage by sparks. The drift time has been measured and a spatial resolution of 250μm has been achieved. Left-right ambiguity can be solved by measuring the charge asymmetry on the walls. The coordinate along the blade is read by external pickup strips. (orig.)

  1. High pressure gas-filled cermet spark gaps

    International Nuclear Information System (INIS)

    Avilov, Eh.A.; Yur'ev, A.L.

    2000-01-01

    The results of modernization of the R-48 and R-49 spark gaps making it possible to improve their electrical characteristics are presented. The design is described and characteristics of gas-filled cermet spark gaps are presented. By the voltage rise time of 5-6 μs in the Marx generator scheme they provide for the pulse break-through voltage of 120 and 150 kV. By the voltage rise time of 0.5-1 μs the break-through voltage of these spark gaps may be increased up to 130 and 220 kV. The proper commutation time is equal to ≤ 0.5 ns. Practical recommendations relative to designing cermet spark gaps are given [ru

  2. Exploring the Performance of Spark for a Scientific Use Case

    Energy Technology Data Exchange (ETDEWEB)

    Sehrish, Saba [Fermilab; Kowalkowski, Jim [Fermilab; Paterno, Marc [Fermilab

    2016-01-01

    We present an evaluation of the performance of a Spark implementation of a classification algorithm in the domain of High Energy Physics (HEP). Spark is a general engine for in-memory, large-scale data processing, and is designed for applications where similar repeated analysis is performed on the same large data sets. Classification problems are one of the most common and critical data processing tasks across many domains. Many of these data processing tasks are both computation- and data-intensive, involving complex numerical computations employing extremely large data sets. We evaluated the performance of the Spark implementation on Cori, a NERSC resource, and compared the results to an untuned MPI implementation of the same algorithm. While the Spark implementation scaled well, it is not competitive in speed to our MPI implementation, even when using significantly greater computational resources.

  3. Knock investigation by flame and radical species detection in spark ignition engine for different fuels

    International Nuclear Information System (INIS)

    Merola, Simona S.; Vaglieco, Bianca M.

    2007-01-01

    The present paper aims to evaluate the phenomena of normal combustion and knocking in a single cylinder, ported fuel injection, four-stroke spark-ignition engine with a four-valve production head. All the measurements were realized in an optically accessible engine equipped with a wide quartz window in the bottom of the chamber. The study was carried out using optical techniques based on flame natural emission imaging and spectroscopy from UV to visible. Radical species such as OH and HCO were detected and correlated to the onset and the duration of knock and presence of hot-spots in end-gas. Measurements were carried out at 1000 rpm with wide-open throttle and stoichiometric mixture. Pure iso-octane, suitable mixtures of iso-octane and n-heptane and commercial gasoline were used

  4. "Photographing money" task pricing

    Science.gov (United States)

    Jia, Zhongxiang

    2018-05-01

    "Photographing money" [1]is a self-service model under the mobile Internet. The task pricing is reasonable, related to the success of the commodity inspection. First of all, we analyzed the position of the mission and the membership, and introduced the factor of membership density, considering the influence of the number of members around the mission on the pricing. Multivariate regression of task location and membership density using MATLAB to establish the mathematical model of task pricing. At the same time, we can see from the life experience that membership reputation and the intensity of the task will also affect the pricing, and the data of the task success point is more reliable. Therefore, the successful point of the task is selected, and its reputation, task density, membership density and Multiple regression of task positions, according to which a nhew task pricing program. Finally, an objective evaluation is given of the advantages and disadvantages of the established model and solution method, and the improved method is pointed out.

  5. Ultra Fast, High Rep Rate, High Voltage Spark Gap Pulser

    Science.gov (United States)

    1995-07-01

    current rise time. The spark gap was designed to have a coaxial geometry reducing its inductance. Provisions were made to pass flowing gas between the...ULTRA FAST, HIGH REP RATE, HIGH VOLTAGE SPARK GAP PULSER Robert A. Pastore Jr., Lawrence E. Kingsley, Kevin Fonda, Erik Lenzing Electrophysics and...Modeling Branch AMSRL-PS-EA Tel.: (908)-532-0271 FAX: (908)-542-3348 U.S. Army Research Laboratory Physical Sciences Directorate Ft. Monmouth

  6. Sparks Will Fly: engineering creative script conflicts

    Science.gov (United States)

    Veale, Tony; Valitutti, Alessandro

    2017-10-01

    Scripts are often dismissed as the stuff of good movies and bad politics. They codify cultural experience so rigidly that they remove our freedom of choice and become the very antithesis of creativity. Yet, mental scripts have an important role to play in our understanding of creative behaviour, since a deliberate departure from an established script can produce results that are simultaneously novel and familiar, especially when others stick to the conventional script. Indeed, creative opportunities often arise at the overlapping boundaries of two scripts that antagonistically compete to mentally organise the same situation. This work explores the computational integration of competing scripts to generate creative friction in short texts that are surprising but meaningful. Our exploration considers conventional macro-scripts - ordered sequences of actions - and the less obvious micro-scripts that operate at even the lowest levels of language. For the former, we generate plots that squeeze two scripts into a single mini-narrative; for the latter, we generate ironic descriptions that use conflicting scripts to highlight the speaker's pragmatic insincerity. We show experimentally that verbal irony requires both kinds of scripts - macro and micro - to work together to reliably generate creative sparks from a speaker's subversive intent.

  7. Automatic spark counting of alpha-tracks in plastic foils

    International Nuclear Information System (INIS)

    Somogyi, G.; Medveczky, L.; Hunyadi, I.; Nyako, B.

    1976-01-01

    The possibility of alpha-track counting by jumping spark counter in cellulose acetate and polycarbonate nuclear track detectors was studied. A theoretical treatment is presented which predicts the optimum residual thickness of the etched foils in which completely through-etched tracks (i.e. holes) can be obtained for alpha-particles of various energies and angles of incidence. In agreement with the theoretical prediction it is shown that a successful spark counting of alpha-tracks can be performed even in polycarbonate foils. Some counting characteristics, such as counting efficiency vs particle energy at various etched foil thicknesses, surface spark density produced by electric breakdowns in unexposed foils vs foil thickness, etc. have been determined. Special attention was given to the spark counting of alpha-tracks entering thin detectors at right angle. The applicability of the spark counting technique is demonstrated in angular distribution measurements of the 27 Al(p,α 0 ) 24 Mg nuclear reaction at Ep = 1899 keV resonance energy. For this study 15 μm thick Makrofol-G foils and a jumping spark counter of improved construction were used. (orig.) [de

  8. Wire chambers: Trends and alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Regler, Meinhard

    1992-05-15

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!.

  9. 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.

  10. Scattering profiles of sparks and combustibility of filter against hot sparks

    International Nuclear Information System (INIS)

    Tobita, Noriyuki; Okada, Takashi; Kashiro, Kashio

    2004-12-01

    An event that a pre-filter burned on fire took place in the glove box dismantlement facility of Plutonium Production Facility, on April 21, 2003. The direct cause of this event was considered to be sparks generated by an abrasive wheel cutter, some of which reached the pre-filter and eventually burned the pre-filter. Further investigation revealed that there exist other deficiencies those of which formed indirect causes of the event, i.e., the wheel cutter was used without protective cover and adequate shield against sparks was not installed during the operation. To prevent similar event in the future, following corrective actions were introduced. Wheel cutter will not be used without protective cover; Incombustible pre-filter will be used; Shield will be place at the front of the pre-filter. We have conducted series of experimental tests in order to evaluate and confirm the validity of these corrective actions as well as determine the cause of the fire. This report present the results of these tests. (author)

  11. Radon diffusion chamber

    International Nuclear Information System (INIS)

    Pretzsch, G.; Boerner, E.; Lehmann, R.; Sarenio, O.

    1986-01-01

    The invention relates to the detection of radioactive gases emitting alpha particles like radon, thoron and their alpha-decaying daughters by means of a diffusion chamber with a passive detector, preferably with a solid state track detector. In the chamber above and towards the detector there is a single metallized electret with negative polarity. The distance between electret and detector corresponds to the range of the alpha particles of radon daughters in air at the most. The electret collects the positively charged daughters and functions as surface source. The electret increases the sensitivity by the factor 4

  12. The Honeycomb Strip Chamber

    International Nuclear Information System (INIS)

    Graaf, Harry van der; Buskens, Joop; Rewiersma, Paul; Koenig, Adriaan; Wijnen, Thei

    1991-06-01

    The Honeycomb Strip Chamber (HSC) is a new position sensitive detector. It consists of a stack of folded foils, forming a rigid honeycomb structure. In the centre of each hexagonal cell a wire is strung. Conducting strips on the foils, perpendicular to the wires, pick up the induced avalanche charge. Test results of a prototype show that processing the signals form three adjacent strips nearest to the track gives a spatial resolution better than 64 μm for perpendicular incident tracks. The chamber performance is only slightly affected by a magnetic field. (author). 25 refs.; 21 figs

  13. Multiple chamber ionization detector

    International Nuclear Information System (INIS)

    Solomon, E.E.

    1982-01-01

    An ionization smoke detector employs a single radiation source in a construction comprising at least two chambers with a center or node electrode. The radioactive source is associated with this central electrode, and its positioning may be adjusted relative to the electrode to alter the proportion of the source that protrudes into each chamber. The source may also be mounted in the plane of the central electrode, and positioned relative to the center of the electrode. The central electrode or source may be made tiltable relative to the body of the detector

  14. 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.

  15. 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.

  16. Experiencing Photographs Qua Photographs: What's So Special about Them?

    Directory of Open Access Journals (Sweden)

    Jiri Benovsky

    2013-01-01

    Full Text Available Merely rhetorically and answering in the negative, Kendall Walton has asked: "Isn't photography just another method people have of making pictures, one that merely uses different tools and materials; cameras, photosensitive paper, and darkroom equipment, rather than canvas, paint, and brushes? And don't the results differ only contingently and in degree, not fundamentally, from pictures of other kinds?" Contrary to Walton and others, I answer with a resounding "Yes" to Walton’s questions in this article. It is a widely shared view that photographs are somehow special and that they fundamentally differ from hand-made pictures such as paintings, both from a phenomenological point of view (in the way we experience them and an epistemic point of view (since they are supposed to have a different that is, greater, epistemic value from paintings that gives us a privileged access to the world. I almost reject the totality of these claims and, as a consequence, there remains little difference between photographs and paintings. As we shall see, “photographs are always partly paintings,” a claim that is true not only of retouched digital photographs but of all photographs, including traditional ones made using photosensitive film and development techniques.

  17. 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.

  18. 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.

  19. The KLOE drift chamber

    International Nuclear Information System (INIS)

    Ferrari, A.

    2002-01-01

    The design and construction of the large drift chamber of the KLOE experiment is presented. The track reconstruction is described, together with the calibration method and the monitoring systems. The stability of operation and the performance are studied with samples of e + e - , K S K L and K + K - events

  20. Drift chamber detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez Laso, L.

    1989-01-01

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, 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)

  1. Drift Chambers detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez laso, L.

    1989-01-01

    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

  2. OPAL Muon Chamber

    CERN Multimedia

    OPAL was one of the 4 experiments installed at the LEP particle accelerator from 1989 to 2000. This is a slice of the outermost layer of OPAL : the muon chambers. This outside layer detects particles which are not stopped by the previous layers. These are mostly muons.

  3. Improvements in ionization chambers

    International Nuclear Information System (INIS)

    Whetten, N.R.; Zubal, C.

    1980-01-01

    A method of reducing mechanical vibrations transmitted to the parallel plate electrodes of ionization chamber x-ray detectors, commonly used in computerized x-ray axial tomography systems, is described. The metal plate cathodes and anodes are mounted in the ionizable gas on dielectric sheet insulators consisting of a composite of silicone resin and glass fibres. (UK)

  4. 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.

  5. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  6. Ion chamber instrument

    International Nuclear Information System (INIS)

    Stephan, D.H.

    1975-01-01

    An electrical ionization chamber is described having a self-supporting wall of cellular material which is of uniform areal density and formed of material, such as foamed polystyrene, having an average effective atomic number between about 4 and about 9, and easily replaceable when on the instrument. (auth)

  7. Review of straw chambers

    International Nuclear Information System (INIS)

    Toki, W.H.

    1990-03-01

    This is a review of straw chambers used in the HRS, MAC, Mark III, CLEO, AMY, and TPC e + e - experiments. The straws are 6--8 mm in diameter, operate at 1--4 atmospheres and obtain resolutions of 45--100 microns. The designs and constructions are summarized and possible improvements discussed

  8. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  9. Wire chamber conference

    International Nuclear Information System (INIS)

    Bartl, W.; Neuhofer, G.; Regler, M.

    1986-02-01

    This booklet contains program and the abstracts of the papers presented at the conference, most of them dealing with performance testing of various types of wire chambers. The publication of proceedings is planned as a special issue of 'Nuclear instruments and methods' later on. All abstracts are in English. An author index for the book of abstracts is given. (A.N.)

  10. Sparking protection for MFTF-B Neutral Beam Power Supplies

    International Nuclear Information System (INIS)

    Cummings, D.B.

    1983-01-01

    This paper describes the upgrade of MFTF-B Neutral Beam Power Supplies for sparking protection. High performance ion sources spark repeatedly so ion source power supplies must be insensitive to sparking. The hot deck houses the series tetrode, arc and filament supplies, and controls. Hot deck shielding has been upgraded and a continuous shield around the arc, filament, gradient grid, and control cables now extends from the hot deck, through the core snubber, to the source. The shield carries accelerating current and connects only to the source. Shielded source cables go through an outer duct which now connects to a ground plane under the hot deck. This hybrid transmission line is a low inductance path for sparks discharging the stray capacitance of the hot deck and isolation transformers, reducing coupling to building steel. Parallel DC current return cables inside the duct lower inductance to reduce inductive turn-off transients. MOVs to ground further limit surges in the remote power supply return. Single point grounding is at the source. No control or rectifier components have been damaged nor are there any known malfunctions due to sparking up to 80 kV output

  11. Research on spark discharge of floating roof tank shunt

    International Nuclear Information System (INIS)

    Bi, Xiaolei; Liu, Quanzhen; Liu, Baoquan; Gao, Xin; Hu, Haiyan; Liu, Juan

    2013-01-01

    In order to quantitatively analyze the spark discharge risk of floating roof tank shunts, the breakdown voltage of shunt has been calculated by Townsend theory, the shunt spark discharge experiment is carried out by using 1.2/50 μs impulse voltage wave, and the relationship between breakdown voltage of shunt spark discharge and air gap is analyzed. It has been indicated by theoretical analysis and experimental study that the small gap is more easily cause spark discharge than the big gap when the contact between shunt and tank shell is poor. When air gap distance is equal to 0.1 cm, average breakdown voltage is 5280 V. When the air gap distance is less than 0.3 cm, experiment data agree well with Townsend theory. Therefore, in the condition of small gap, Townsend theory can be used to calculated breakdown voltage of shunt. Finally, based on the above conclusions, improvements for avoiding the spark discharge risk of shunt of floating roof tanks have been proposed.

  12. Spark counting technique with an aluminium oxide film

    International Nuclear Information System (INIS)

    Kawai, H.; Koga, T.; Morishima, H.; Niwa, T.; Nishiwaki, Y.

    1980-01-01

    Automatic spark counting of etch-pits on a polycarbonate film produced by nuclear fission fragments is now used for neutron monitoring in several countries. A method was developed using an aluminium oxide film instead of a polycarbonate as the neutron detector. Aluminium oxide films were prepared as follows: A cleaned aluminium plate as an anode and a nickel plate as a cathode were immersed in dilute sulfuric acid solution and electric current flowed between the electrodes at 12degC for 10-30 minutes. Electric current density was about 10 mA/cm 2 . The aluminium plate was then kept in boiling water for 10-30 minutes for sealing. The thickness of the aluminium oxide layer formed was about 1μm. The aluminium plate attached to a plate of suitable fissionable material, such as uranium or thorium, was irradiated with neutrons and set in a usual spark counter for fission track counting. One electrode was the aluminium plate and the other was an aluminized polyester sheet. Sparked pulses were counted with a usual scaler. The advantage of using spark counting with an aluminium oxide film for neutron monitoring is rapid measurement of neutron exposure, since chemical etching which is indispensable for spark counting with a polycarbonate detector film, is not needed. (H.K.)

  13. Sparking protection for MFTF-B neutral beam power supplies

    International Nuclear Information System (INIS)

    Cummings, D.B.

    1983-01-01

    This paper describes the upgrade of MFTF-B Neutral Beam Power Supplies for sparking protection. High performance ion sources spark repeatedly so ion source power supplies must be insensitive to sparking. The hot deck houses the series tetrode, arc and filament supplies, and controls. Hot deck shielding has been upgraded and a continuous shield around the arc, filament, gradient grid, and control cables now extends from the hot deck, through the core snubber, to the source. The shield carries accelerating current and connects only to the source. Shielded source cables go through an outer duct which now connects to a ground plane under the hot deck. This hybrid transmission line is a low inductance path for sparks discharging the stray capacitance of the hot deck and isolation transformers, reducing coupling to building steel. Parallel dc current return cables inside the duct lower inductance to reduce inductive turn-off transients. MOVs to ground further limit surges in the remote power supply return. Single point grounding is at the source. No control or rectifier components have been damaged nor are there any known malfunctions due to sparking up to 80 kV output

  14. Laboratory EXAFS using photographic method

    International Nuclear Information System (INIS)

    Joshi, S K; Gaur, A; Johari, A; Shrivastava, B D

    2009-01-01

    Laboratory EXAFS facilities have been used since long. However, EXAFS data analysis has not been reported as yet for the spectra recorded photographically. Though from our laboratory we have been reporting various studies employing X-ray spectrographs using the photographic method of registration of EXAFS spectra, but the data has never been analyzed using the Fourier transformation method and fitting with standards. This paper reports the study of copper metal EXAFS spectra at the K-edge recorded photographically employing a 400 mm curved mica crystal Cauchois type spectrograph with 0.5 kW tungsten target X-ray tube. The data obtained in digital form with the help of a microphotometer has been processed using EXAFS data analysis programs Athena and Artemis. The experimental data for copper metal foil have been fitted with the theoretical standards. The results have been compared with those obtained from another laboratory EXAFS set up employing 12 kW Rigaku rotating anode, Johansson-type spectrometer with Si(311) monochromator crystal and scintillation counter. The results have also been compared with those obtained from SSRL. The parameters obtained for the first two shells from the photographic method are comparable with those obtained from the other two methods. The present work shows that the photographic method of registering EXAFS spectra in laboratory set up using fixed target X-ray tubes can also be used for getting structural information at least for the first two coordination shells.

  15. Laboratory EXAFS using photographic method

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S K [Government College, Badnawar (Dhar)-454660 (India); Gaur, A; Johari, A; Shrivastava, B D, E-mail: joshisantoshk@yahoo.co [School of Studies in Physics, Vikram University, Ujjain-456010 (India)

    2009-11-15

    Laboratory EXAFS facilities have been used since long. However, EXAFS data analysis has not been reported as yet for the spectra recorded photographically. Though from our laboratory we have been reporting various studies employing X-ray spectrographs using the photographic method of registration of EXAFS spectra, but the data has never been analyzed using the Fourier transformation method and fitting with standards. This paper reports the study of copper metal EXAFS spectra at the K-edge recorded photographically employing a 400 mm curved mica crystal Cauchois type spectrograph with 0.5 kW tungsten target X-ray tube. The data obtained in digital form with the help of a microphotometer has been processed using EXAFS data analysis programs Athena and Artemis. The experimental data for copper metal foil have been fitted with the theoretical standards. The results have been compared with those obtained from another laboratory EXAFS set up employing 12 kW Rigaku rotating anode, Johansson-type spectrometer with Si(311) monochromator crystal and scintillation counter. The results have also been compared with those obtained from SSRL. The parameters obtained for the first two shells from the photographic method are comparable with those obtained from the other two methods. The present work shows that the photographic method of registering EXAFS spectra in laboratory set up using fixed target X-ray tubes can also be used for getting structural information at least for the first two coordination shells.

  16. Dust Plate, Retina, Photograph: Imaging on Experimental Surfaces in Early Nineteenth-Century Physics.

    Science.gov (United States)

    Ramalingam, Chitra

    2015-09-01

    This article explores the entangled histories of three imaging techniques in early nineteenth-century British physical science, techniques in which a dynamic event (such as a sound vibration or an electric spark) was made to leave behind a fixed trace on a sensitive surface. Three categories of "sensitive surface" are examined in turn: first, a metal plate covered in fine dust; second, the retina of the human eye; and finally, a surface covered with a light-sensitive chemical emulsion (a photographic plate). For physicists Michael Faraday and Charles Wheatstone, and photographic pioneer William Henry Fox Talbot, transient phenomena could be studied through careful observation and manipulation of the patterns wrought on these different surfaces, and through an understanding of how the imaging process unfolded through time. This exposes the often-ignored materiality and temporality of epistemic practices around nineteenth-century scientific images said to be "drawn by nature."

  17. Development of the method of sensitivity improvement of photographic film applicable in high-energy physics experiments

    International Nuclear Information System (INIS)

    Gokieli, V.D.

    1986-01-01

    Sensitivity improvement of photographic films applicable in high-energy physics experiments is discussed. To get optimal operating conditions for photographic film PT-6 to check its physical properties on electron beam and in cosmic rays a set for film samples exposure in visible spectrum and in X-rays is constructed. The set includes a start up device, high-voltage pulse oscillator, shapers, a chamber for the sample exposure, voltage divider and electron oscillograph

  18. Measurements of Radon Concentration in Yemen Using Spark Counter

    International Nuclear Information System (INIS)

    Arafa, W.; Abou-Leila, M.; Hafiz, M.E.; Al-Glal, N.

    2011-01-01

    Spark counter has been designed and realized and the optimum applied voltage was found to be 600 V. Excellent consistent agreements was observed between counted number of tracks by spark counter and reading by optical microscope. Radon concentration in some houses in Sana'a and Hodeidah cities in Yemen had been performed using LR-115 SSNTD and spark counter system. The average radon concentration in both cities was far lower the alert value. The results showed that radon concentration in the metropolitan area Sana'a was higher than that in Hodeidah city. Also, it was observed that old residential houses had higher levels of radon concentrations have compared to newly built houses in the metropolitan area Sana'a

  19. A miniature spark counter for public communication and education

    International Nuclear Information System (INIS)

    Mao, C.H.; Weng, P.S.

    1987-01-01

    The fabrication of a miniature spark counter for public communication and education using naturally occurring radon as a radioactive source without involving any man-made radioactivity is described. The battery-powered miniature spark counter weighs 2.07 kg with a volume of 4.844 x 10/sup -4/ m/sup 3/. The circuitry consists of seven major components: timer, high-voltage power supply, attenuator, noninverting amplifier, low-pass filter, one-shot generator, and counter. Cellulose nitrate films irradiated with alpha particles from radon emanating from soil were etched and counted. The visible sparks during counting are rather heuristic, which can be used to demonstrate naturally occurring radioactivity in classrooms or showplaces

  20. 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.

  1. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  2. Vienna Wire Chamber Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    After those of 1978 and 1980, a third Wire Chamber Conference was held from 15-18 February in the Technical University of Vienna. Eight invited speakers covered the field from sophisticated applications in biology and medicine, via software, to the state of the art of gaseous detectors. In some forty other talks the speakers tackled in more detail the topics of gaseous detectors, calorimetry and associated electronics and software

  3. Wire chamber gases

    International Nuclear Information System (INIS)

    Va'vra, J.

    1992-04-01

    In this paper, we describe new developments in gas mixtures which have occurred during the last 3--4 years. In particular, we discuss new results on the measurement and modeling of electron drift parameters, the modeling of drift chamber resolution, measurements of primary ionization and the choice of gas for applications such as tracking, single electron detection, X-ray detection and visual imaging. In addition, new results are presented on photon feedback, breakdown and wire aging

  4. Adobe Photoshop CC for photographers

    CERN Document Server

    Evening, Martin

    2014-01-01

    Adobe Photoshop for Photographers 2014 Release by Photoshop hall-of-famer and acclaimed digital imaging professional Martin Evening has been fully updated to include detailed instruction for all of the updates to Photoshop CC 2014 on Adobe's Creative Cloud, including significant new features, such as Focus Area selections, enhanced Content-Aware filling, and new Spin and Path blur gallery effects. This guide covers all the tools and techniques photographers and professional image editors need to know when using Photoshop, from workflow guidance to core skills to advanced techniques for profess

  5. Double chambered right ventricle

    International Nuclear Information System (INIS)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung

    1983-01-01

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure

  6. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  7. Argus drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, M; Nagovizin, V; Hasemann, H; Michel, E; Schmidt-Parzefall, W; Wurth, R; Kim, P

    1983-11-15

    The ARGUS detector came into operation at the DORIS-II e/sup +/s/sup -/ storage ring at the end of 1982. Its two meter long drift chamber contains 5940 sense and 24588 field wires organized in uniform 18x18.8 mm/sup 2/ drift cells filling the whole volume. These cells form 36 layers, 18 of which provide stereo views. Each sense wire is equipped with a single hit TDC and ADC for coordinate and dE/dx measurements. The chamber is operated with propane to improve momentum and dE/dx resolution. The drift chamber design and initial performance are presented. With a very crude space-time relation approximation and without all the necessary corrections applied a spatial resolution of about 200 ..mu..m was obtained for half of the drift cell volume. Further corrections should improve this result. An intrinsic dE/dx resolution of 4.2% and an actual resolution of 5% were obtained for cosmic muons and also for Bhabha scattered electrons. An actual dE/dx resolution of 5.6% was obtained for pions from e/sup +/e/sup -/ annihilation data with almost no track selection. A relativistic rise of 30% was observed in good agreement with theory. The long-term stability is still to be investigated.

  8. Argus target chamber

    International Nuclear Information System (INIS)

    Rienecker, F. Jr.; Glaros, S.S.; Kobierecki, M.

    1975-01-01

    A target chamber for application in the laser fusion program must satisfy some very basic requirements. (1) Provide a vacuum on the order of 10 -6 torr. (2) Support a microscopically small target in a fixed point in space and verify its location within 5 micrometers. (3) Contain an adjustable beam focusing system capable of delivering a number of laser beams onto the target simultaneously, both in time and space. (4) Provide access for diagnostics to evaluate the results of target irradiation. (5) Have flexibility to allow changes in targets, focusing optics and number of beams. The ARGUS laser which is now under construction at LLL will have a target chamber which meets these requirements in a simple economic manner. The chamber and auxiliary equipment are described, with reference to two double beam focusing systems; namely, lenses and ellipsoidal mirrors. Provision is made for future operation with four beams, using ellipsoidal mirrors for two-sided illumination and lens systems for tetragonal and tetrahedral irradiation

  9. Analysis of Plant Breeding on Hadoop and Spark

    Directory of Open Access Journals (Sweden)

    Shuangxi Chen

    2016-01-01

    Full Text Available Analysis of crop breeding technology is one of the important means of computer-assisted breeding techniques which have huge data, high dimensions, and a lot of unstructured data. We propose a crop breeding data analysis platform on Spark. The platform consists of Hadoop distributed file system (HDFS and cluster based on memory iterative components. With this cluster, we achieve crop breeding large data analysis tasks in parallel through API provided by Spark. By experiments and tests of Indica and Japonica rice traits, plant breeding analysis platform can significantly improve the breeding of big data analysis speed, reducing the workload of concurrent programming.

  10. Vacuum spark breakdown model based on exploding metal wire phenomena

    International Nuclear Information System (INIS)

    Haaland, J.

    1984-06-01

    Spark source mass spectra (SSMS) indicates that ions are extracted from an expanding and decaying plasma. The intensity distribution shows no dependance on vaporization properties of individual elements which indicates explosive vapour formation. This seems further to be a requirement for bridging a vacuum gap. A model including plasma ejection from a superheated anode spot by a process similar to that of an exploding metal wire is proposed. The appearance of hot plasma points in low inductance vacuum sparks can then be explained as exploding micro particles ejected from a final central anode spot. The phenomenological model is compared with available experimental results from literature, but no extensive quantification is attempted

  11. A note on preserving the spark of a matrix

    Directory of Open Access Journals (Sweden)

    Marcin Skrzynski

    2015-05-01

    Full Text Available Let Mm× n(F be the vector space of all m× n matrices over a field F. In the case where m ≥ n, char (F ≠ 2 and F has at least five elements, we give a complete characterization of linear maps Φ : Mm× n(F → Mm× n(F such that spark(Φ (A = spark(A for any A ∈ Mm× n(F.

  12. Phase characterisation in spark plasma sintered TiPt alloy

    CSIR Research Space (South Africa)

    Chikosha, S

    2011-12-01

    Full Text Available stream_source_info chikosha_2011.pdf.txt stream_content_type text/plain stream_size 4354 Content-Encoding UTF-8 stream_name chikosha_2011.pdf.txt Content-Type text/plain; charset=UTF-8 PHASE CHARACTERISATION IN SPARK... to form “necks”  Radiant Joule heat and pressure drives “neck” growth and material transfer © CSIR 2006 www.csir.co.za Page 6 Objective  Produce TiPt alloy compacts by Spark plasma sintering (SPS) of equiatomic...

  13. Wire chambers: Trends and alternatives

    International Nuclear Information System (INIS)

    Regler, Meinhard

    1992-01-01

    The subtitle of this year's Vienna Wire Chamber Conference - 'Recent Trends and Alternative Techniques' - signalled that it covered a wide range of science and technology. While an opening Vienna talk by wire chamber pioneer Georges Charpak many years ago began 'Les funerailles des chambres a fils (the burial of wire chambers)', the contrary feeling this year was that wire chambers are very much alive!

  14. Criteria for controlled atmosphere chambers

    International Nuclear Information System (INIS)

    Robinson, J.N.

    1980-03-01

    The criteria for design, construction, and operation of controlled atmosphere chambers intended for service at ORNL are presented. Classification of chambers, materials for construction, design criteria, design, controlled atmosphere chamber systems, and operating procedures are presented. ORNL Safety Manual Procedure 2.1; ORNL Health Physics Procedure Manual Appendix A-7; and Design of Viewing Windows are included in 3 appendices

  15. 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...

  16. Practice and Exploration of New Rural Construction in West Bank of Taiwan Strait Led by Spark Science and Technology

    OpenAIRE

    Li, Chaocan

    2013-01-01

    According to practice and exploration of spark program for 26 years in Quanzhou, the main model and their effects of new rural construction in west bank of Taiwan Strait led by spark science and technology were expounded. Six spark program systems were established, consisting of policy support guide, science and technology project lead, experts’ intelligence support, spark science and technology training, sci-tech information service and spark program demonstration. Five spark projects were...

  17. A projection graphic display for the computer aided analysis of bubble chamber images

    International Nuclear Information System (INIS)

    Solomos, E.

    1979-01-01

    A projection graphic display for aiding the analysis of bubble chamber photographs has been developed by the Instrumentation Group of EF Division at CERN. The display image is generated on a very high brightness cathode ray tube and projected on to the table of the scanning-measuring machines as a superposition to the image of the bubble chamber. The display can send messages to the operator and aid the measurement by indicating directly on the chamber image the tracks which are measured correctly or not. (orig.)

  18. A note on photographing otoliths

    African Journals Online (AJOL)

    The sagiu..al otoliths of rlShes have in recent years become importanttuonomic aids. Forthis purpose high quality photographs have become essential to illustrate such fine: structures as the crislae and the colliculi which art often useful in distinguishing between closely related species. The method described bdow proved ...

  19. Globes, Maps, Photographs: Geographic Tools.

    Science.gov (United States)

    McDermott, Paul D.; And Others

    This compilation of reprinted articles that originally appeared in the Journal of Geography from September 1969 through the May 1970 issues, is intended to help teachers use globes, maps, and photographs with skill and understanding. The articles were designed with several objectives in mind: 1) to provide information regarding the design,…

  20. 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.

  1. Cultural influences on Facebook photographs.

    Science.gov (United States)

    Huang, Chih-Mao; Park, Denise

    2013-01-01

    Prior research in social psychology indicates that East Asians from collectivistic and interdependent sociocultural systems are more sensitive to contextual information than Westerners, whereas Westerners with individualistic and independent representation have a tendency to process focal and discrete attributes of the environment. Here we have demonstrated that such systematic cultural variations can also be observed in cyberspace, focusing on self-presentation of photographs on Facebook, the most popular worldwide online social network site. We examined cultural differences in face/frame ratios for Facebook profile photographs in two studies. For Study 1, 200 digital profile face photographs of active Facebook users were randomly selected from native and immigrant Taiwanese and Americans. For Study 2, 312 Facebook profiles of undergraduate students of six public universities in East Asia (Hong Kong, Singapore, and Taiwan) and the United States (California and Texas) were randomly selected. Overall, the two studies clearly showed that East Asian Facebook users are more likely to deemphasize their faces compared to Americans. Specifically, East Asians living in Hong Kong, Singapore, and Taiwan exhibited a predilection for context inclusiveness in their profile photographs, whereas Americans tended to prioritize their focal face at the expense of the background. Moreover, East Asian Facebook users had lower intensity of facial expression than Americans on their photographs. These results demonstrate marked cultural differences in context-inclusive styles versus object-focused styles between East Asian and American Facebook users. Our findings extend previous findings from the real world to cyberspace, and provide a novel approach to investigate cognition and behaviors across cultures by using Facebook as a data collection platform.

  2. Cultural influences on Facebook photographs

    Science.gov (United States)

    Huang, Chih-Mao; Park, Denise

    2012-01-01

    Prior research in social psychology indicates that East Asians from collectivistic and interdependent sociocultural systems are more sensitive to contextual information than Westerners, whereas Westerners with individualistic and independent representation have a tendency to process focal and discrete attributes of the environment. Here we have demonstrated that such systematic cultural variations can also be observed in cyberspace, focusing on self-presentation of photographs on Facebook, the most popular worldwide online social network site. We examined cultural differences in face/frame ratios for Facebook profile photographs in two studies. For Study 1, 200 digital profile face photographs of active Facebook users were randomly selected from native and immigrant Taiwanese and Americans. For Study 2, 312 Facebook profiles of undergraduate students of six public universities in East Asia (Hong Kong, Singapore, and Taiwan) and the United States (California and Texas) were randomly selected. Overall, the two studies clearly showed that East Asian Facebook users are more likely to deemphasize their faces compared to Americans. Specifically, East Asians living in Hong Kong, Singapore, and Taiwan exhibited a predilection for context inclusiveness in their profile photographs, whereas Americans tended to prioritize their focal face at the expense of the background. Moreover, East Asian Facebook users had lower intensity of facial expression than Americans on their photographs. These results demonstrate marked cultural differences in context-inclusive styles versus object-focused styles between East Asian and American Facebook users. Our findings extend previous findings from the real world to cyberspace, and provide a novel approach to investigate cognition and behaviors across cultures by using Facebook as a data collection platform. PMID:22468606

  3. Experimental investigation of the vibrational and thermal response of a laser spark plug

    Science.gov (United States)

    Yoder, Gregory S.

    A study was conducted in order to evaluate the external thermal and vibrational effects on the operation of a laser ignition system for internal combustion (IC) engine applications. West Virginia University (WVU) in conjunction with the National Energy Technology Laboratory (NETL) have constructed a prototype laser spark plug which has been designed to mount directly onto the head of a natural gas engine for the purpose of igniting an air/fuel (A/F) mixture in the engine's combustion chamber. To be considered as a viable replacement for the conventional electrode-based ignition system, integrity, durability and reliability must be justified. Thermal and oscillatory perturbations induced upon the ignition system are major influences that affect laser spark plug (LSP) operation and, therefore, quantifying these effects is necessary to further the advancement and development of this technology. The passively q-switched Nd:YAG laser was mounted on Bruel & Kjaer (B&K) Vibration Exciter Type 4808 Shaker in conjunction with at B&K Power Amplifier Type 2719, which was oscillated in 10 Hz intervals from 0 to 60 Hz using a sine wave to mimic natural gas engine operation. The input signal simulated the rotational velocity of the engine operating from 0 to 3600 RPM with the laser mounted in three different axial orientations. The laser assembly was wrapped with medium-temperature heat tape, outfitted with thermocouples and heated from room temperature to 140 ºF to simulate the temperatures that the LSP may experience when installed on an engine. The acceleration of the payload was varied between 50% and 100% of the oscillator's maximum allowable acceleration in each mounting orientation resulting in a total of 294 total setpoints. For each setpoint, pulse width, pulse width variation, q-switch delay, jitter and output energy were measured and recorded. Each of these dependent variables plays a critical role in multi photon ionization and precise control is necessary to limit

  4. Review of wire chamber aging

    International Nuclear Information System (INIS)

    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

  5. Space plasma simulation chamber

    International Nuclear Information System (INIS)

    1986-01-01

    Scientific results of experiments and tests of instruments performed with the Space Plasma Simulation Chamber and its facility are reviewed in the following six categories. 1. Tests of instruments on board rockets, satellites and balloons. 2. Plasma wave experiments. 3. Measurements of plasma particles. 4. Optical measurements. 5. Plasma production. 6. Space plasms simulations. This facility has been managed under Laboratory Space Plasma Comittee since 1969 and used by scientists in cooperative programs with universities and institutes all over country. A list of publications is attached. (author)

  6. SparkText: Biomedical Text Mining on Big Data Framework

    Science.gov (United States)

    He, Karen Y.; Wang, Kai

    2016-01-01

    Background Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment. Results In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers) from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM), and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes. Conclusions This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research. PMID:27685652

  7. Evolution of Spark plasma using nitrogen laser shadowgraphy system

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.

    1994-07-01

    A simple, low cost, home built high power nitrogen laser is used as the light source for a shadowgraphy system. A series of shadowgrams depicting the temporal growth of a spark plasma discharge is obtained. The results could be useful in plasma diagnostic studies. (author). 5 refs, 6 figs

  8. knock characteristics analysis of a supercharged spark ignition

    African Journals Online (AJOL)

    user

    The power output of a spark ignition engine could be improved by boosting the ... that the presence of aromatics was responsible for the better anti-knock ..... System, a Master's Thesis in the Institutionen för ... Maintenance and Reliability, Vol.

  9. SPARK RttT: Year One Fidelity and Implementation

    Science.gov (United States)

    Rochford, Joseph A.; O'Neill, Adrienne; Gelb, Adele; Ross, Kimberly

    2014-01-01

    Developed in 2003 by the Sisters of Charity Foundation of Canton with a grant from the Kellogg Foundation, "Supporting Partnerships to Assure Ready Kids" ("SPARK Ohio") is a family-centered kindergarten readiness program that works with families, schools, and the community. From its initial sites in Stark County, "SPARK…

  10. Towards constrained optimal control of spark-ignition engines

    NARCIS (Netherlands)

    Feru, E.; Luo, X.

    2015-01-01

    In this paper, the torque control problem for spark-ignition engines is considered. The objective is to provide good output torque tracking with minimum fuel consumption, while avoiding engine knock and misre. To this end, three control strategies are proposed: a feed-forward controller with

  11. Utilization of Alcohol Fuel in Spark Ignition and Diesel Engines.

    Science.gov (United States)

    Berndt, Don; Stengel, Ron

    These five units comprise a course intended to prepare and train students to conduct alcohol fuel utilization seminars in spark ignition and diesel engines. Introductory materials include objectives and a list of instructor requirements. The first four units cover these topics: ethanol as an alternative fuel (technical and economic advantages,…

  12. SparkText: Biomedical Text Mining on Big Data Framework.

    Directory of Open Access Journals (Sweden)

    Zhan Ye

    Full Text Available Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment.In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM, and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes.This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research.

  13. SparkText: Biomedical Text Mining on Big Data Framework.

    Science.gov (United States)

    Ye, Zhan; Tafti, Ahmad P; He, Karen Y; Wang, Kai; He, Max M

    Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment. In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers) from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM), and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes. This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research.

  14. Material machining with pseudo-spark electron beams

    International Nuclear Information System (INIS)

    Benker, W.; Christiansen, J.; Frank, K.; Gundel, H.; Redel, T.; Stetter, M.

    1989-01-01

    The authors give a brief description of the production of pseudo-spark (low pressure gas discharge) electron beams. They illustrate the use of these electron beams for machining not only conducting, semiconducting and insulating materials, but also thin layers of such materials as high temperature superconducting ceramics

  15. Multi-spark discharge system for preparation of nutritious water

    Science.gov (United States)

    Nakaso, Tetsushi; Harigai, Toru; Kusumawan, Sholihatta Aziz; Shimomura, Tomoya; Tanimoto, Tsuyoshi; Suda, Yoshiyuki; Takikawa, Hirofumi

    2018-01-01

    The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3- concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was about 6 times higher than that of our previous system. It was confirmed that the NO2-, O3, and H2O2 concentrations in the water were also increased by treating the water using the MSDS.

  16. Saffman-Taylor streamers: Mutual finger interaction in spark formation

    NARCIS (Netherlands)

    Luque, A.; Brau, F.; Ebert, U.

    2008-01-01

    Bunches of streamers form the early stages of sparks and lightning but theory presently concentrates on single streamers or on coarse approximations of whole breakdown trees. Here a periodic array of interacting streamer discharges in a strong homogeneous electric field is studied in density or

  17. The physics of photoconductive spark gap switching : pushing the frontiers

    NARCIS (Netherlands)

    Hendriks, J.

    2006-01-01

    Photoconductive switching of an atmospheric, air-¯lled spark gap by a high-power fem- tosecond laser is a novel approach for switching high voltages into pulses with a very fast rise time (order ps) and almost no shot-to-shot time variation (jitter). Such a switch makes it possible to synchronize

  18. Theoretical investigation of a photoconductively switched high-voltage spark gap

    NARCIS (Netherlands)

    Broks, B.H.P.; Hendriks, J.; Brok, W.J.M.; Brussaard, G.J.H.; Mullen, van der J.J.A.M.

    2006-01-01

    In this contribution, a photoconductively switched high-voltage spark gap with an emphasis on theswitching behavior is modeled. It is known experimentally that not all of the voltage that is present at the input of the spark gap is switched, but rather a fraction of it drops across the spark gap.

  19. The Results of a Randomized Control Trial Evaluation of the SPARK Literacy Program

    Science.gov (United States)

    Jones, Curtis J.; Christian, Michael; Rice, Andrew

    2016-01-01

    The purpose of this report is to present the results of a two-year randomized control trial evaluation of the SPARK literacy program. SPARK is an early grade literacy program developed by Boys & Girls Clubs of Greater Milwaukee. In 2010, SPARK was awarded an Investing in Innovation (i3) Department of Education grant to further develop the…

  20. A more modern look for the Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    When the Council Chamber was renovated, the old photographs displayed on the walls were taken down... they've now been replaced by new panels printed on Plexiglas. The theme of the exhibition is still the history of CERN, but it now features the very latest from graphic design. Fabienne Marcastel, who designed it, tells us more. Two of the new panels recently installed in the Council Chamber. The presentation is simple and elegant. The content is based essentially on the accelerators and the aim of the graphic design is not to attract the public's attention to the panels but rather to provide a pleasant décor for the Chamber's users. "The old photographs stopped at the LEP. The new panels show the history of CERN but also what the Laboratory is like today. Visually, the plan is the starting point, the key to understanding how CERN has changed. It shows how CERN occupies the land it is built on," explains Fabienne Marcastel, the exhibition's graphic designer. The four panels a...

  1. INFLUENCE OF ELECTRIC SPARK ON HARDNESS OF CARBON STEEL

    Directory of Open Access Journals (Sweden)

    I. O. Vakulenko

    2014-03-01

    Full Text Available Purpose. The purpose of work is an estimation of influence of an electric spark treatment on the state of mouldable superficial coverage of carbon steel. Methodology. The steel of fragment of railway wheel rim served as material for research with chemical composition 0.65% С, 0.67% Mn, 0.3% Si, 0.027% P, 0.028% S. Structural researches were conducted with the use of light microscopy and methods of quantitative metallography. The structural state of the probed steel corresponded to the state after hot plastic deformation. The analysis of hardness distribution in the micro volumes of cathode metal was carried out with the use of microhardness tester of type of PMT-3. An electric spark treatment of carbon steel surface was executed with the use of equipment type of EFI-25M. Findings. After electric spark treatment of specimen surface from carbon steel the forming of multi-layered coverage was observed. The analysis of microstructure found out the existence of high-quality distinctions in the internal structure of coverage metal, depending on the probed area. The results obtained in the process are confirmed by the well-known theses, that forming of superficial coverage according to technology of electric spark is determined by the terms of transfer and crystallization of metal. The gradient of structures on the coverage thickness largely depends on development of structural transformation processes similar to the thermal character influence. Originality. As a result of electric spark treatment on the condition of identical metal of anode and cathode, the first formed layer of coverage corresponds to the monophase state according to external signs. In the volume of coverage metal, the appearance of carbide phase particles is accompanied by the decrease of microhardness values. Practical value. Forming of multi-layered superficial coverage during electric spark treatment is accompanied by the origin of structure gradient on a thickness. The effect

  2. Heavenly bodies the photographer's guide to astrophotography

    CERN Document Server

    Krages, Esq, Bert P

    2003-01-01

    Detailing the photographic equipment and astronomical instruments needed to capture celestial images, this guide shows how astrophotography can be accessible to all photographers. Included is a detailed introduction to basic astronomy with information on mapping the sky, locating celestial bodies, and planning an expedition to photograph astronomical phenomena. Photographers learn how to determine the color sensitivity of various films and achieve the best possible exposure, how to ensure a captivating composition, and how commercially processed prints can support their artistic vision. Whethe

  3. D Photographs in Cultural Heritage

    Science.gov (United States)

    Schuhr, W.; Lee, J. D.; Kiel, St.

    2013-07-01

    This paper on providing "oo-information" (= objective object-information) on cultural monuments and sites, based on 3D photographs is also a contribution of CIPA task group 3 to the 2013 CIPA Symposium in Strasbourg. To stimulate the interest in 3D photography for scientists as well as for amateurs, 3D-Masterpieces are presented. Exemplary it is shown, due to their high documentary value ("near reality"), 3D photography support, e.g. the recording, the visualization, the interpretation, the preservation and the restoration of architectural and archaeological objects. This also includes samples for excavation documentation, 3D coordinate calculation, 3D photographs applied for virtual museum purposes and as educational tools. In addition 3D photography is used for virtual museum purposes, as well as an educational tool and for spatial structure enhancement, which in particular holds for inscriptions and in rock arts. This paper is also an invitation to participate in a systematic survey on existing international archives of 3D photographs. In this respect it is also reported on first results, to define an optimum digitization rate for analog stereo views. It is more than overdue, in addition to the access to international archives for 3D photography, the available 3D photography data should appear in a global GIS(cloud)-system, like on, e.g., google earth. This contribution also deals with exposing new 3D photographs to document monuments of importance for Cultural Heritage, including the use of 3D and single lense cameras from a 10m telescope staff, to be used for extremely low earth based airborne 3D photography, as well as for "underwater staff photography". In addition it is reported on the use of captive balloon and drone platforms for 3D photography in Cultural Heritage. It is liked to emphasize, the still underestimated 3D effect on real objects even allows, e.g., the spatial perception of extremely small scratches as well as of nuances in color differences

  4. Erosion on spark plug electrodes; Funkenerosion an Zuendkerzenelektroden

    Energy Technology Data Exchange (ETDEWEB)

    Rager, J.

    2006-07-01

    Durability of spark plugs is mainly determined by spark gap widening, caused by electrode wear. Knowledge about the erosion mechanisms of spark plug materials is of fundamental interest for the development of materials with a high resistance against electrode erosion. It is therefore crucial to identify those parameters which significantly influence the erosion behaviour of a material. In this work, a reliable and reproducible testing method is presented which produces and characterizes electrode wear under well-defined conditions and which is capable of altering parameters specifically. Endurance tests were carried out to study the dependence of the wear behaviour of pure nickel and platinum on the electrode temperature, gas, electrode gap, electrode diameter, atmospheric pressure, and partial pressure of oxygen. It was shown that erosion under nitrogen is negligible, irrespective of the material. This disproves all common mechanism discussed in the literature explaining material loss of spark plug electrodes. Based on this observation and the variation of the mentioned parameters a new erosion model was deduced. This relies on an oxidation of the electrode material and describes the erosion of nickel and platinum separately. For nickel, electrode wear is caused by the removal of an oxide layer by the spark. In the case of platinum, material loss occurs due to the plasma-assisted formation and subsequent evaporation of volatile oxides in the cathode spot. On the basis of this mechanism a new composite material was developed whose erosion resistance is superior to pure platinum. Oxidation resistant metal oxide particles were added to a platinum matrix, thus leading to a higher erosion resistance of the composite. However, this can be decreased by a side reaction, the separation of oxygen from the metal oxides, which effectively assists the oxidation of the matrix. This reaction can be suppressed by using highly stable oxides, characterized by a large negative Gibbs

  5. 31 CFR 91.10 - Photographs.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Photographs. 91.10 Section 91.10 Money and Finance: Treasury Regulations Relating to Money and Finance REGULATIONS GOVERNING CONDUCT IN OR ON THE BUREAU OF THE MINT BUILDINGS AND GROUNDS § 91.10 Photographs. The taking of photographs on...

  6. 22 CFR 51.26 - Photographs.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Photographs. 51.26 Section 51.26 Foreign Relations DEPARTMENT OF STATE NATIONALITY AND PASSPORTS PASSPORTS Application § 51.26 Photographs. The applicant must submit with his or her application photographs as prescribed by the Department that are a...

  7. 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...

  8. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

    Goretzki, G.

    1981-01-01

    The two methods of cardiac chamber scintiscanning, i.e. 'first pass' and 'ECG-triggered' examinations, are explained and compared. Two tables indicate the most significant radiation doses of the applied radio tracers, i.e. 99m-Tc-pertechnetate and 99m-Tc-HSA, to which a patient is exposed. These averaged values are calculated from various data given in specialised literature. On the basis of data given in literature, an effective half-life of approximately 5 hours in the intravascular space was calculated for the erythrocytes labelled with technetium 99m. On this basis, the radiation doses for the patients due to 99m-Tc-labelled erythrocytes are estimated. The advantages and disadvantages of the two methods applied for cardiac chamber scintiscanning are put into contrast and compared with the advantages and disadvantages of the quantitative X-ray cardiography of the left heart. The still existing problems connected with the assessment of ECG-triggered images are discussed in detail. The author performed investigations of his own, which concerned the above-mentioned problems. (orig./MG) [de

  9. Near wall combustion modeling in spark ignition engines. Part A: Flame–wall interaction

    International Nuclear Information System (INIS)

    Demesoukas, Sokratis; Caillol, Christian; Higelin, Pascal; Boiarciuc, Andrei; Floch, Alain

    2015-01-01

    Highlights: • A model for flame–wall interaction in addition to flame wrinkling by turbulence is proposed. • Two sparkplug positions and two lengths are used in a test engine for model validation. • Flame–wall interaction decreases the maximum values of cylinder pressure and heat release rates. • The impact of combustion chamber geometry is taken into account by the flame–wall interaction model. - Abstract: Research and design in the field of spark ignition engines seek to achieve high performance while conserving fuel economy and low pollutant emissions. For the evaluation of various engine configurations, numerical simulations are favored, since they are quick and less expensive than experiments. Various zero-dimensional combustion models are currently used. Both flame front reactions and post-flame processes contribute to the heat release rate. The first part of this study focuses on the role of the flame front on the heat release rate, by modeling the interaction of the flame front with the chamber wall. Post-flame reactions are dealt with in Part B of the study. The basic configurations of flame quenching in laminar flames are also applicable in turbulent flames, which is the case in spark ignition engines. A simplified geometric model of the combustion chamber was used to calculate the mean flame surface, the flame volume and the distribution of flame surface as a function of the distance from the wall. The flame–wall interaction took into account the geometry of the combustion chamber and of the flame, aerodynamic turbulence and the in-cylinder pressure and temperature conditions, through a phenomenological attenuation function of the wrinkling factor. A modified global wrinkling factor as a function of the mean surface distance distribution from the wall was calculated. The impact of flame–wall interaction was simulated for four configurations of the sparkplug position and length: centered and lateral position, and standard and projected

  10. Photographs of the southern heavens

    CERN Document Server

    West, R M

    1975-01-01

    The 1 m Schmidt telescope of the European Southern Observatory (ESO) has been used for a number of sky surveys. In particular a main task has been an examination of the southern night sky between declinations of -20 degrees and -90 degrees . This exercise is known as the ESO(B) Survey (or Quick Blue Survey); some of the more interesting results are shown and are briefly discussed. The photographic plates used were Kodak II a-o. There are photographs of the two Magellanic Clouds and of the galaxy NGC 1313 and the globular cluster NGC 6752. A spectrogram of our Galaxy for wavelengths in the band 3900 A to 4900 A, taken with the telescope's large objective prism is also shown. (0 refs).

  11. Diogene pictorial drift chamber

    International Nuclear Information System (INIS)

    Gosset, J.

    1984-01-01

    A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive)

  12. 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

  13. Simulation of chamber experiments

    International Nuclear Information System (INIS)

    Ivanov, V.G.

    1981-01-01

    The description of the system of computer simulation of experiments conducted by means of track detectors with film data output is given. Considered is the principle of organization of computer model of the chamber experiment comprising the following stages: generation of events, generation of measurements, ge-- neration of scanning results, generation of distorbions, generated data calibration, filtration, events reconstruction, kinematic identification, total results tape formation, analysis of the results. Generation programs are formed as special RAM-files, where the RAM-file is the text of the program written in FORTRAN and divided into structural elements. All the programs are a ''part of the ''Hydra'' system. The system possibilities are considered on the base of the CDSC-6500 computer. The five-beam event generation, creation data structure for identification and calculation by the kinematic program take about 1s of CDC-6500 computer time [ru

  14. Nucleation in bubble chambers

    International Nuclear Information System (INIS)

    Harigel, G.G.

    1988-01-01

    Various sources and mechanisms for bubble formation in superheated liquids are discussed. Bubble chambers can be filled with a great variety of liquids, such as e.g. the cryogenic liquids hydrogen, deuterium, neon, neon/hydrogen mixtures, argon, nitrogen, argon/nitrogen mixtures, or the warm liquids propane and various Freon like Freon-13B1. The superheated state is normally achieved by a rapid movement of an expansion piston or membrane, but can also be produced by standing ultrasonic waves, shock waves, or putting liquids under tension. Bubble formation can be initiated by ionizing particles, by intense (laser) light, or on rough surfaces. The creation of embryonic bubbles is not completely understood, but the macroscopic growth and condensation can be calculated, allowing to estimate the dynamic heat load [fr

  15. Spark discharge and flame inception analysis through spectroscopy in a DISI engine fuelled with gasoline and butanol

    Science.gov (United States)

    Irimescu, A.; Merola, S. S.

    2017-10-01

    Extensive application of downsizing, as well as the application of alternative combustion control with respect to well established stoichiometric operation, have determined a continuous increase in the energy that is delivered to the working fluid in order to achieve stable and repeatable ignition. Apart from the complexity of fluid-arc interactions, the extreme thermodynamic conditions of this initial combustion stage make its characterization difficult, both through experimental and numerical techniques. Within this context, the present investigation looks at the analysis of spark discharge and flame kernel formation, through the application of UV-visible spectroscopy. Characterization of the energy transfer from the spark plug’s electrodes to the air-fuel mixture was achieved by the evaluation of vibrational and rotational temperatures during ignition, for stoichiometric and lean fuelling of a direct injection spark ignition engine. Optical accessibility was ensured from below the combustion chamber through an elongated piston design, that allowed the central region of the cylinder to be investigated. Fuel effects were evaluated for gasoline and n-butanol; roughly the same load was investigated in throttled and wide-open throttle conditions for both fuels. A brief thermodynamic analysis confirmed that significant gains in efficiency can be obtained with lean fuelling, mainly due to the reduction of pumping losses. Minimal effect of fuel type was observed, while mixture strength was found to have a stronger influence on calculated temperature values, especially during the initial stage of ignition. In-cylinder pressure was found to directly determine emission intensity during ignition, but the vibrational and rotational temperatures featured reduced dependence on this parameter. As expected, at the end of kernel formation, temperature values converged towards those typically found for adiabatic flames. The results show that indeed only a relatively small part

  16. Peltier-based cloud chamber

    Science.gov (United States)

    Nar, Sevda Yeliz; Cakir, Altan

    2018-02-01

    Particles produced by nuclear decay, cosmic radiation and reactions can be identified through various methods. One of these methods that has been effective in the last century is the cloud chamber. The chamber makes visible cosmic particles that we are exposed to radiation per second. Diffusion cloud chamber is a kind of cloud chamber that is cooled by dry ice. This traditional model has some application difficulties. In this work, Peltier-based cloud chamber cooled by thermoelectric modules is studied. The new model provided uniformly cooled base of the chamber, moreover, it has longer lifetime than the traditional chamber in terms of observation time. This gain has reduced the costs which spent each time for cosmic particle observation. The chamber is an easy-to-use system according to traditional diffusion cloud chamber. The new model is portable, easier to make, and can be used in the nuclear physics experiments. In addition, it would be very useful to observe Muons which are the direct evidence for Lorentz contraction and time expansion predicted by Einsteins special relativity principle.

  17. CHLOE: a system for the automatic handling of spark pictures

    International Nuclear Information System (INIS)

    Butler, J.W.; Hodges, D.; Royston, R.

    The system for automatic data handling uses commercially available or state-of-the-art components. The system is flexible enough to accept information from various types of experiments involving photographic data acquisition

  18. Magnetic field influence on substructure formed by electric spark treatment

    International Nuclear Information System (INIS)

    Reza Rahbari, G.; Ivanov, A.N.

    1996-01-01

    The substructure of surface layer (about 10 microns thick) has been studied by x-ray line broadening technique in the samples of plain carbon steel (0.45%C) after electric spark doping with and without magnetic field (MF). The applied spark pulse energy was 0.12 J and MF induction varied from 0 to 0.08 T. The electrode material was the same as that of the treated sample. It has been observed that the MF reduces the tensile residual surface stresses from 660 ± 15MPa (no MF) to 260 ± 15MPa (B=0.053 T). The analysis of x-ray line broadening has revealed only the existence of microstrains, which are dependent of the MF magnitude. The microstrains have been related to the randomly distributed dislocation with the density of about 3x10 sup 11 cm sup -2

  19. 100 kV reliable accurately-synchronized spark gap

    International Nuclear Information System (INIS)

    Bosamykin, V.S.; Gerasimov, A.I.; Zenkov, D.I.

    1987-01-01

    100 kV three-electrode spark gap filled with 40% SF 6 +60% N 2 mixture under the pressure of ∼ 1 MPa, which has spread Δt ≤ ± 5 ns of operating time delay in the range of 10 4 triggerings and commutation energy of 2.5 kJ, providing electric strength is 100%, is described; at 10 kJ Δt is less than ± 10 ns for 10 3 triggerings. Parallel connection of 16 groups, each consisting of 5 spark gaps with series connection, electric strength being 100%, in the pulse charging unit of Arkadiev-Marx generator being in operation for several years manifested their high efficiency; mutual group spread is ≤ ± 15 ns

  20. Striated filamentary sparks produced by a CO2 TEA laser

    International Nuclear Information System (INIS)

    Schmieder, R.W.

    1979-01-01

    Sparks in the form of long, thin filaments having quasi-periodic longitudinal light and dark regions (striations) in time-integrated images have been ovserved in various gases using a CO 2 TEA laser. Typically, a 50-mJ pulse will produce a filament 1 cm long and 130 μm in diameter, with more than 150 striations spaced 50 μm apart in atmospheric air. Each striation is associated with the formation of a plasma region by one pulse in train of pulses from the mode-locked laser, and the filament results from the formation of successive (nearly identical) region, each displaced from the previous one toward the laser. The possible use of these sparks as a light source in diagnostics is noted

  1. Large area spark counters with fine time and position resolution

    International Nuclear Information System (INIS)

    Ogawa, A.; Atwood, W.B.; Fujiwara, N.; Pestov, Yu.N.; Sugahara, R.

    1983-10-01

    Spark counters trace their history back over three decades but have been used in only a limited number of experiments. The key properties of these devices include their capability of precision timing (at the sub 100 ps level) and of measuring the position of the charged particle to high accuracy. At SLAC we have undertaken a program to develop these devices for use in high energy physics experiments involving large detectors. A spark counter of size 1.2 m x 0.1 m has been constructed and has been operating continuously in our test setup for several months. In this talk I will discuss some details of its construction and its properties as a particle detector. 14 references

  2. CMS Analysis and Data Reduction with Apache Spark

    Energy Technology Data Exchange (ETDEWEB)

    Gutsche, Oliver [Fermilab; Canali, Luca [CERN; Cremer, Illia [Magnetic Corp., Waltham; Cremonesi, Matteo [Fermilab; Elmer, Peter [Princeton U.; Fisk, Ian [Flatiron Inst., New York; Girone, Maria [CERN; Jayatilaka, Bo [Fermilab; Kowalkowski, Jim [Fermilab; Khristenko, Viktor [CERN; Motesnitsalis, Evangelos [CERN; Pivarski, Jim [Princeton U.; Sehrish, Saba [Fermilab; Surdy, Kacper [CERN; Svyatkovskiy, Alexey [Princeton U.

    2017-10-31

    Experimental Particle Physics has been at the forefront of analyzing the world's largest datasets for decades. The HEP community was among the first to develop suitable software and computing tools for this task. In recent times, new toolkits and systems for distributed data processing, collectively called "Big Data" technologies have emerged from industry and open source projects to support the analysis of Petabyte and Exabyte datasets in industry. While the principles of data analysis in HEP have not changed (filtering and transforming experiment-specific data formats), these new technologies use different approaches and tools, promising a fresh look at analysis of very large datasets that could potentially reduce the time-to-physics with increased interactivity. Moreover these new tools are typically actively developed by large communities, often profiting of industry resources, and under open source licensing. These factors result in a boost for adoption and maturity of the tools and for the communities supporting them, at the same time helping in reducing the cost of ownership for the end-users. In this talk, we are presenting studies of using Apache Spark for end user data analysis. We are studying the HEP analysis workflow separated into two thrusts: the reduction of centrally produced experiment datasets and the end-analysis up to the publication plot. Studying the first thrust, CMS is working together with CERN openlab and Intel on the CMS Big Data Reduction Facility. The goal is to reduce 1 PB of official CMS data to 1 TB of ntuple output for analysis. We are presenting the progress of this 2-year project with first results of scaling up Spark-based HEP analysis. Studying the second thrust, we are presenting studies on using Apache Spark for a CMS Dark Matter physics search, comparing Spark's feasibility, usability and performance to the ROOT-based analysis.

  3. Loits skandaalitses gaalal. Sparks Rabarockil. Pärimusmuusika Ait

    Index Scriptorium Estoniae

    2008-01-01

    Pärnu Kontserdimajas Eesti muusikaauhindade galal üle astunud rockansambel Loits röövis koostöös kultuskirjaniku Sven Kivisildnikuga aasta metal/punk-artisti auhinna, mis pidi minema industrial-metal-artistile Finish Me Off. Ameerika bänd Sparks 14. juunil Järvakandis Rabarockil. Viljandis Tasuja pst.6 avati Eesti Pärimusmuusika Keskuse uus kodu - Pärimusmuusika Ait

  4. effect of gasket of varying thickness on spark ignition engines

    African Journals Online (AJOL)

    DJFLEX

    In the study of Toyota, In-line, 4 cylinders, spark ignition engine using gaskets of varying thicknesses. (1.75mm, 3.5mm, 5.25mm, 7mm and 8.75mm) between the cylinder head and the engine block, the performance characteristics of the engine was investigated via the effect of engine speed on brake power, brake thermal ...

  5. High repetition rate burst-mode spark gap

    International Nuclear Information System (INIS)

    Faltens, A.; Reginato, L.; Hester, R.; Chesterman, A.; Cook, E.; Yokota, T.; Dexter, W.

    1978-01-01

    Results are presented on the design and testing of a pressurized gas blown spark gap switch capable of high repetition rates in a burst mode of operation. The switch parameters which have been achieved are as follows: 220-kV, 42-kA, a five pulse burst at 1-kHz, 12-ns risetime, 2-ns jitter at a pulse width of 50-ns

  6. Modeling of the Inductance of a Blumlein Circuit Spark Gap

    International Nuclear Information System (INIS)

    Aboites, V; Rendón, L; Hernández, A I; Valdés, E

    2015-01-01

    In this paper we present an analysis of the time-varying inductance in the spark gap of a Blumlein circuit. We assume several mathematical expressions to describe the inductance and compare theoretical and computational calculations with experimental results. The time-varying inductance is approximated by a constant, a straight line and two parables which differ in their concavity. This is the first time to our knowledge, in which the time-varying ignition inductance of a nitrogen laser is modeled

  7. SparkJet characterizations in quiescent and supersonic flowfields

    Science.gov (United States)

    Emerick, T.; Ali, M. Y.; Foster, C.; Alvi, F. S.; Popkin, S.

    2014-12-01

    The aerodynamic community has studied active flow control actuators for some time, and developments have led to a wide variety of devices with various features and operating mechanisms. The design requirements for a practical actuator used for active flow control include reliable operation, requisite frequency and amplitude modulation capabilities, and a reasonable lifespan while maintaining minimal cost and design complexity. An active flow control device called the SparkJet actuator has been developed for high-speed flight control and incorporates no mechanical/moving parts, zero net mass flux capabilities and the ability to tune the operating frequency and momentum throughput. This actuator utilizes electrical power to deliver high-momentum flow with a very fast response time. The SparkJet actuator was characterized on the benchtop using a laser-based microschlieren visualization technique and maximum blast wave and jet front velocities of ~400 and ~310 m/s were, respectively, measured in the flowfield. An increase in jet front velocity from 240 to 310 m/s during subatmospheric (60 kPa) testing reveals that the actuator may have greater control authority at lower ambient pressures, which correspond to high-altitude flight conditions for air vehicles. A SparkJet array was integrated into a flat plate and tested in a Mach 1.5 crossflow. Phase-conditioned shadowgraph results revealed a maximum flow deflection angle of 5° created by the SparkJet 275 µs after the actuator was triggered in single-shot mode. Burst mode operation of frequencies up to 700 Hz revealed similar results during wind tunnel testing. Following these tests, the actuator trigger mechanism was improved and the ability of the actuator to be discharged in burst mode at a frequency of 1 kHz was achieved.

  8. The time response function of spark counters and RPCs

    International Nuclear Information System (INIS)

    Gobbi, A.; Mangiarotti, A.

    2003-01-01

    The fluctuation theory for the avalanche growth with and without space charge effects is briefly summarized and compared to a broad field of applications. These include spark counters as well as timing and trigger RPCs operated in avalanche mode. A large domain in electrical field strength, pressure, gap size and gas mixture type is covered. A reasonable agreement with the experiment is observed, giving confidence on the validity of both assumptions and treatment of the theory

  9. Production of uranium-molybdenum particles by spark-erosion

    International Nuclear Information System (INIS)

    Cabanillas, E.D.; Lopez, M.; Pasqualini, E.E.; Cirilo Lombardo, D.J.

    2004-01-01

    With the spark-erosion method we have produced spheroidal particles of an uranium-molybdenum alloy using pure water as dielectric. The particles were characterized by optical metallography, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Mostly spherical particles of UO 2 with a distinctive size distribution with peaks centered at 70 and 10 μm were obtained. The particles have central inclusions of U and Mo compounds

  10. Production of uranium-molybdenum particles by spark-erosion

    Energy Technology Data Exchange (ETDEWEB)

    Cabanillas, E.D. E-mail: cabanill@cnea.gov.ar; Lopez, M.; Pasqualini, E.E.; Cirilo Lombardo, D.J

    2004-01-01

    With the spark-erosion method we have produced spheroidal particles of an uranium-molybdenum alloy using pure water as dielectric. The particles were characterized by optical metallography, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Mostly spherical particles of UO{sub 2} with a distinctive size distribution with peaks centered at 70 and 10 {mu}m were obtained. The particles have central inclusions of U and Mo compounds.

  11. Particular bi-fuel application of spark ignition engines

    Science.gov (United States)

    Raţiu, S.; Alexa, V.; Kiss, I.

    2016-02-01

    This paper presents a comparative test concerning the operation of a spark-ignition engine, make: Dacia 1300, model: 810.99, fuelled alternatively with gasoline and LPG (Liquefied Petroleum Gas). The tests carried out show, on the one hand, the maintenance of power and torque performances in both engine fuelling cases, for all the engine operation regimes, and, on the other hand, a considerable decrease in CO and HC emissions when using poor mixtures related to LPG fuelling.

  12. Modelling of spark to ignition transition in gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Akram, M.

    1996-10-01

    This thesis pertains to the models for studying sparking in chemically inert gases. The processes taking place in a spark to flame transition can be segregated into physical and chemical processes, and this study is focused on physical processes. The plasma is regarded as a single-substance material. One and two-dimensional models are developed. The transfer of electrical energy into thermal energy of the gas and its redistribution in space and time along with the evolution of a plasma kernel is studied in the time domain ranging from 10 ns to 40 micros. In the case of ultra-fast sparks, the propagation of the shock and its reflection from a rigid wall is presented. The influence of electrode shape and the gap size on the flow structure development is found to be a dominating factor. It is observed that the flow structure that has developed in the early stage more or less prevails at later stages and strongly influences the shape and evolution of the hot kernel. The electrode geometry and configuration are responsible for the development of the flow structure. The strength of the vortices generated in the flow field is influenced by the power input to the gap and their location of emergence is dictated by the electrode shape and configuration. The heat transfer after 2 micros in the case of ultra-fast sparks is dominated by convection and diffusion. The strong mixing produced by hydrodynamic effects and the electrode geometry give the indication that the magnetic pinch effect might be negligible. Finally, a model for a multicomponent gas mixture is presented. The chemical kinetics mechanism for dissociation and ionization is introduced. 56 refs

  13. Gas temperature of capacitance spark discharge in air

    International Nuclear Information System (INIS)

    Ono, Ryo; Nifuku, Masaharu; Fujiwara, Shuzo; Horiguchi, Sadashige; Oda, Tetsuji

    2005-01-01

    Capacitance spark discharge has been widely used for studying the ignition of flammable gas caused by electrostatic discharge. In the present study, the gas temperature of capacitance spark discharge is measured. The gas temperature is an important factor in understanding the electrostatic ignition process because it influences the reaction rate of ignition. Spark discharge is generated in air with a pulse duration shorter than 100 ns. The discharge energy is set to 0.03-1 mJ. The rotational and vibrational temperatures of the N 2 molecule are measured using the emission spectrum of the N 2 second positive system. The rotational and vibrational temperatures are estimated to be 500 and 5000 K, respectively, which are independent of the discharge energy. This result indicates that most of the electron energy is consumed in the excitation of vibrational levels of molecules rather than the heating of the gas. The gas temperature after discharge is also measured by laser-induced fluorescence of OH radicals. It is shown that the gas temperature increases after discharge and reaches approximately 1000 K at 3 μs after discharge. Then the temperature decreases at a rate in the range of 8-35 K/μs depending on the discharge energy

  14. Spark igniter having precious metal ground electrode inserts

    International Nuclear Information System (INIS)

    Ryan, N.A.

    1988-01-01

    This patent describes an igniter comprising a shell of a shell metal alloy which is resistant to spark erosion and corrosion, the shell having a firing end which terminates at its lower end in an annular ring, an insulator sealed within the metal shell and having a central bore and a surface extending inwardly toward the bore from the annular ring, a center electrode sealed within the bore of the insulator and having a firing end which is in spark gap relation with the annular ring of the shell and so positioned that a spark discharge between the firing end and the annular ring occurs along the inwardly extending surface of the insulator, and a plurality of oxidation and erosion resistant inserts, each of the inserts comprising a body of a metal selected from the group consisting of iridium, osmium, ruthenium, rhodium, platinum, and tungsten or an alloy or a ductile alloy of one of the foregoing metals, each of the bodies being embedded within a matching opening which extends from the exterior of the shell through the annular ring, being bonded to the shell

  15. River water remediation using pulsed corona, pulsed spark or ozonation

    Energy Technology Data Exchange (ETDEWEB)

    Izdebski, T.; Dors, M. [Polish Academy of Sciences, Szewalski Inst. of Fluid Flow Machiney, Fiszera (Poland). Centre for Plasma and Laser Engineering; Mizeraczyk, J. [Polish Academy of Sciences, Szewalski Inst. of Fluid Flow Machiney, Fiszera (Poland). Centre for Plasma and Laser Engineering; Gdynia Maritime Univ., Morska (Poland). Dept. of Marine Electronics

    2010-07-01

    The most common reason for epidemic formation is the pollution of surface and drinking water by wastewater bacteria. Pathogenic microorganisms that form the largest part of this are fecal bacteria, such as escherichia coli (E. coli). Wastewater treatment plants reduce the amount of the fecal bacteria by 1-3 orders of magnitude, depending on the initial number of bacteria. There is a lack of data on waste and drinking water purification by the electrohydraulic discharges method, which causes the destruction and inactivation of viruses, yeast, and bacteria. This paper investigated river water cleaning from microorganisms using pulsed corona, spark discharge and ozonization. The paper discussed the experimental setup and results. It was concluded that ozonization is the most efficient method of water disinfection as compared with pulsed spark and pulsed corona discharges. The pulsed spark discharge in water was capable of killing all microorganism similarly to ozonization, but with much lower energy efficiency. The pulsed corona discharge was found to be the less effective method of water disinfection. 21 refs., 4 figs.

  16. Research on retailer data clustering algorithm based on Spark

    Science.gov (United States)

    Huang, Qiuman; Zhou, Feng

    2017-03-01

    Big data analysis is a hot topic in the IT field now. Spark is a high-reliability and high-performance distributed parallel computing framework for big data sets. K-means algorithm is one of the classical partition methods in clustering algorithm. In this paper, we study the k-means clustering algorithm on Spark. Firstly, the principle of the algorithm is analyzed, and then the clustering analysis is carried out on the supermarket customers through the experiment to find out the different shopping patterns. At the same time, this paper proposes the parallelization of k-means algorithm and the distributed computing framework of Spark, and gives the concrete design scheme and implementation scheme. This paper uses the two-year sales data of a supermarket to validate the proposed clustering algorithm and achieve the goal of subdividing customers, and then analyze the clustering results to help enterprises to take different marketing strategies for different customer groups to improve sales performance.

  17. The little holographic bubble chambers

    International Nuclear Information System (INIS)

    Herve, A.

    1983-01-01

    The lifetime study of the charmed particles has readvanced the idea to use holography for the little fast-cycle bubble chambers. A pilot experiment has been realised in 1982 with a little bubble chamber filled up with freon-115. 40000 holograms have been recorded [fr

  18. Damage Atlas for Photographic materials

    Directory of Open Access Journals (Sweden)

    Kristel Van Camp

    2010-11-01

    Full Text Available La conservation des documents photographiques peut nécessiter des interventions préventives ou curatives. Ce choix est guidé par leur état de conservation. Une meilleure connaissance des détériorations est donc cruciale. Le répertoire présenté ici essaie de les classifier selon des caractéristiques spécifiques et leur niveau de gravité. Les différents types de dégradation sont illustrés et décrits avec une terminologie précise. L’auteur propose en regard de ceux-ci l’intervention qui semble la plus appropriée. Ce répertoire s’adresse à toutes les personnes concernées par la photographie, qu’ils soient dans le milieu de la conservation ou dans le domaine artistique, dans les musées ou dans les archives. In order to rescue a damaged photographic object, preventive or conservative actions are needed. Knowing the specific characteristics of different types of damage is crucial. A damage atlas can provide these characteristics. With this atlas the damage can be recognised and appropriate actions can be taken. This damage atlas offers a first attempt to such a characterisation in the field of photography. The damage atlas contains images and the necessary information about damage on photographic material. The atlas with special annotations about the terminology and the grade of the damage is meant for everybody who works with photographic material, as well in museums as in archives.

  19. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

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

    2000-01-01

    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 was

  20. Experimental study on surface properties of the PMMA used in high power spark gaps

    Science.gov (United States)

    Han, Ruoyu; Wu, Jiawei; Ding, Weidong; Liu, Yunfei; Gou, Yang

    2017-10-01

    This paper studies the surface properties of the Polymethylmethacrylate (PMMA) insulator samples used in high power spark gaps. Experiments on surface morphology, surface profile, surface chemical composition and surface leakage current were performed. Metal particles ejected in tangent direction of discharge spots were researched on the sample surface. Three kinds of distinct bands were found on the surface after 1500 shots: colorless and transparent sinking band, black band, and grey powdered coating band. The thickness of the coating band was tens of microns and the maximum radial erosion rate was about 10 μm/C. Surface content analysis indicated that the powdered coating was a mixture of decomposed insulator material and electrode material oxides. In addition, leakage current significantly depended on water content in the chamber and presented an U-shape curve distribution along the insulator surface, in keeping with the amount of powdered coating due to shock waves. Possible reasons of the surface property changes were discussed. Electroconductive oxides of low valence states of Cu and W produced by the reactions between electrode materials and arc plasmas were considered to be the cause of dielectric performance degradation.

  1. Determination of knock characteristics in spark ignition engines: an approach based on ensemble empirical mode decomposition

    International Nuclear Information System (INIS)

    Li, Ning; Liang, Caiping; Yang, Jianguo; Zhou, Rui

    2016-01-01

    Knock is one of the major constraints to improve the performance and thermal efficiency of spark ignition (SI) engines. It can also result in severe permanent engine damage under certain operating conditions. Based on the ensemble empirical mode decomposition (EEMD), this paper proposes a new approach to determine the knock characteristics in SI engines. By adding a uniformly distributed and finite white Gaussian noise, the EEMD can preserve signal continuity in different scales and therefore alleviates the mode-mixing problem occurring in the classic empirical mode decomposition (EMD). The feasibilities of applying the EEMD to detect the knock signatures of a test SI engine via the pressure signal measured from combustion chamber and the vibration signal measured from cylinder head are investigated. Experimental results show that the EEMD-based method is able to detect the knock signatures from both the pressure signal and vibration signal, even in initial stage of knock. Finally, by comparing the application results with those obtained by short-time Fourier transform (STFT), Wigner–Ville distribution (WVD) and discrete wavelet transform (DWT), the superiority of the EEMD method in determining knock characteristics is demonstrated. (paper)

  2. Numerical investigation of natural gas direct injection properties and mixture formation in a spark ignition engine

    Directory of Open Access Journals (Sweden)

    Yadollahi Bijan

    2014-01-01

    Full Text Available In this study, a numerical model has been developed in AVL FIRE software to perform investigation of Direct Natural Gas Injection into the cylinder of Spark Ignition Internal Combustion Engines. In this regard two main parts have been taken into consideration, aiming to convert an MPFI gasoline engine to direct injection NG engine. In the first part of study multi-dimensional numerical simulation of transient injection process, mixing and flow field have been performed via three different validation cases in order to assure the numerical model validity of results. Adaption of such a modeling was found to be a challenging task because of required computational effort and numerical instabilities. In all cases present results were found to have excellent agreement with experimental and numerical results from literature. In the second part, using the moving mesh capability the validated model has been applied to methane Injection into the cylinder of a Direct Injection engine. Five different piston head shapes along with two injector types have been taken into consideration in investigations. A centrally mounted injector location has been adapted to all cases. The effects of injection parameters, combustion chamber geometry, injector type and engine RPM have been studied on mixing of air-fuel inside cylinder. Based on the results, suitable geometrical configuration for a NG DI Engine has been discussed.

  3. X-ray photographic apparatus

    International Nuclear Information System (INIS)

    1977-01-01

    The X-ray photographic system is designed for medical applications. Two detectors are used for surveys in different planes, and produce electrical signals which are supplied to a comparator. The electron beams are examined according to a system of reference time steps. The apparatus includes a light source and a photo-detector and enables a reference signal to be produced against which the detected signals are compared. The beam source is formed from an electron gun, an extractor electrode and an anode; beam then passes through a collimator. (G.C.)

  4. Specification for personal photographic dosemeters

    International Nuclear Information System (INIS)

    1981-01-01

    The 1981 British/International Standard Specification, prepared under the direction of the Nuclear Engineering Standards Committee and TC85 of the International Organization for Standardization, is described for personal photographic dosemeters. The Standard specifies classification, characteristics and test procedures to determine absorbed doses due to X or gamma radiations (energy less than 3 MeV) and absorbed doses due to beta radiation (max. energy 0.6 to 3 MeV), whether or not accompanied by X, gamma or bremsstrahlung photon radiation. The Standard is particularly applicable to dosemeters intended to be carried on the chest or wrist. (U.K.)

  5. 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).

  6. Investigation of Spark Ignition and Autoignition in Methane and Air Using Computational Fluid Dynamics and Chemical Reaction Kinetics. A numerical Study of Ignition Processes in Internal Combustion Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nordrik, R.

    1993-12-01

    The processes in the combustion chamber of internal combustion engines have received increased attention in recent years because their efficiencies are important both economically and environmentally. This doctoral thesis studies the ignition phenomena by means of numerical simulation methods. The fundamental physical relations include flow field conservation equations, thermodynamics, chemical reaction kinetics, transport properties and spark modelling. Special attention is given to the inclusion of chemical kinetics in the flow field equations. Using his No Transport of Radicals Concept method, the author reduces the computational efforts by neglecting the transport of selected intermediate species. The method is validated by comparison with flame propagation data. A computational method is described and used to simulate spark ignition in laminar premixed methane-air mixtures and the autoignition process of a methane bubble surrounded by hot air. The spark ignition simulation agrees well with experimental results from the literature. The autoignition simulation identifies the importance of diffusive and chemical processes acting together. The ignition delay times exceed the experimental values found in the literature for premixed ignition delay, presumably because of the mixing process and lack of information on low temperature reactions in the skeletal kinetic mechanism. Transient turbulent methane jet autoignition is simulated by means of the KIVA-II code. Turbulent combustion is modelled by the Eddy Dissipation Concept. 90 refs., 81 figs., 3 tabs.

  7. Upgrade for detection system of JARREL ASH 70-000 atomic emission spectrography with source of arc - spark

    International Nuclear Information System (INIS)

    Santa Cruz D E; Grau F N; Bellavigna H J; Garavaglia R N; Fernandez R O; Servant R

    2012-01-01

    Methodologies used in spectrochemical analysis have showed breakthroughs in last decades due to the newest digital technologies. The simultaneous determination of multiple elements in a short time has been allowed by the development of solid state multichannel detectors. Since its beginning CNEA has developed several spectroscopic methodologies that have been applied to the area of fuels and specific materials of the nuclear activity. The Analytical Chemistry Department has an atomic emission spectrograph with a source of arc/spark whose focal length is 3.4 meters and a spectral dispersion from 2.5 to 5 A/mm. This equipment was originally equipped with photographic detection. This feature although allowed the simultaneous detection of multiple elements, their response (photographic plate) has been not linear and their data's treatment has been very complex. Two alternatives of digital detection have been examined: CCD2 and CMOS3 according to the progress achieved in the instrumentation that is applied to similar techniques. After exhaustive evaluation an arrangement of 9 linear CCD detectors located in the focal plane originally occupied by 2 x10 inch photographic plates was chosen. The software provided by the manufacturer has been insufficient for cover our analytical necessities due to the requirements of our instrumental application. This led to develop an own program for our applications. Today, our detection system includes an assembly of 7 detectors and an acquisition program with basic control that has been developed in-house. Calibration curves for some chemical elements have shown very promising results, the sensitivity has increased at least 10 times and an important improvement of accuracy of the measurements has also been achieved thanks to our modification. An upgrade with an associated database that will allow obtaining spectra in 3D configuration and extend the instrumental capabilities to second order is being prepared (author)

  8. A Photographer From Ankara: Osman Darcan

    Directory of Open Access Journals (Sweden)

    Gülseren Mungan Yavuztürk

    2015-12-01

    Full Text Available This work introduces Osman Darcan, an important name in the history of Ankara photography studios. Darcan followed in the footsteps of famous Austrian photographer Othmar Pferschy, whom he met in Istanbul, to go on to create his own valuable work. On leaving the Public Press Authority Photo Film Center, where he worked as a newsreel photographer and film operator, in 1943 he began taking photographs at the Tatbikat Theater at the Ankara State Conservatoire, where he continued as the photographer for the State Theater until the end of his life. At the same time, this master photographer took the pictures of a select coterie of Ankara’s leading individuals and well-known performers at a studio he opened on Anafartalar Caddesi. In both these roles, his photographs evoke admiration thanks to Darcan’s professional abilities and level of artistry.

  9. Completion of installation of DT and RPC chambers before Cosmic Challenge

    CERN Multimedia

    Mimmo Dattola

    2006-01-01

    All the drift tube ("DT") and resistive plate chambers ("RPC") packages foreseen to be installed in the central barrel ring ("YB0") before the magnet test have been installed (some are missing in the photograph but have since been installed). These silver-coloured rectangular boxes in the gaps between the steel of the rings (red in the image) detect muons. Chambers for Sectors 4 and 5 (sector 1 is at the 9 o'clock position and the counting is clockwise) as well as a couple of chambers in the support "feet" (sectors 9 and 11) will be installed after the magnet test. Chambers for sectors 1 and 7 will be installed in the underground cavern ("UXC") - the latter will be in the places used for the lifting and lowering of the ring.

  10. Sintering, consolidation, reaction and crystal growth by the spark plasma system (SPS)

    Energy Technology Data Exchange (ETDEWEB)

    Omori, M. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

    2000-08-15

    The graphite die set in spark plasma system (SPS) is heated by a pulse direct current. Weak plasma, discharge impact, electric field and electric current, which are based on this current, induce good effects on materials in the die. The surface films of aluminum and pure WC powders are ruptured by the spark plasma. Pure AlN powder is sintered without sintering additives in the electric field. The spark plasma leaves discharge patterns on insulators. Organic fibers are etched by the spark plasma. Thermosetting polyimide is consolidated by the spark plasma. Insoluble polymonomethylsilane is rearranged into the soluble one by the spark plasma. A single crystal of CoSb{sub 3} is grown from the compound powders in the electric field by slow heating. Coupled crystals of eutectic powder are connected with each other in the electric field. (orig.)

  11. Photographic quality assurance in diagnostic radiology, nuclear medicine, and radiation therapy. Volume II. Photographic processing, quality assurance, and the evaluation of photographic materials. Final report

    International Nuclear Information System (INIS)

    Gray, J.E.; Vucich, J.J.

    1977-03-01

    Contents: Sensitometers, densitometers, and testing equipment; Pitfalls of the photographic (and radiographic) process; Evaluation and optimization of photographic processes; Quality assurance; Odds 'n' ends

  12. Micro plate fission chamber development

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Jiang Li; Liu Rong; Wang Dalun

    2014-01-01

    To conduct the measurement of neutron flux and the fission rate distribution at several position in assemblies, the micro plate fission chamber was designed and fabricated. Since the requirement of smaller volume and less structure material was taken into consideration, it is convinient, commercial and practical to use fission chamber to measure neutron flux in specific condition. In this paper, the structure of fission chamber and process of fabrication were introduced and performance test result was presented. The detection efficiency is 91.7%. (authors)

  13. Pelletron general purpose scattering chamber

    International Nuclear Information System (INIS)

    Chatterjee, A.; Kailas, S.; Kerekette, S.S.; Navin, A.; Kumar, Suresh

    1993-01-01

    A medium sized stainless steel scattering chamber has been constructed for nuclear scattering and reaction experiments at the 14UD pelletron accelerator facility. It has been so designed that several types of detectors, varying from small sized silicon surface barrier detectors to medium sized gas detectors and NaI detectors can be conveniently positioned inside the chamber for detection of charged particles. The chamber has been planned to perform the following types of experiments : angular distributions of elastically scattered particles, fission fragments and other charged particles, angular correlations for charged particles e.g. protons, alphas and fission fragments. (author). 2 figs

  14. "Photographers Are the Devil": An Essay in the Historiography of Photographing Schools

    Science.gov (United States)

    Hardcastle, John

    2013-01-01

    Today, the use of photographs in publications and exhibitions is commonplace, but this was not always so. This article shows how photographs of certain schools that have had lasting impact on design stand in ambiguous relationships to the buildings themselves. Photographs function as part of the design process; they record details of construction…

  15. Spark Ignition Characteristics of a L02/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine s augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  16. Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  17. Spark Ignition LPG for Hydrogen Gas Combustion the Reduction Furnace ME-11 Process

    International Nuclear Information System (INIS)

    Achmad Suntoro

    2007-01-01

    Reverse engineering method for automatic spark-ignition system of LPG to burn hydrogen gaseous in the reducing process of ME-11 furnace has been successfully implemented using local materials. A qualitative study to the initial behaviour of the LPG flame system has created an idea by modification to install an automatic spark-ignition of the LPG on the reducing furnace ME-11. The automatic spark-ignition system has been tested and proved working well. (author)

  18. Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

    Science.gov (United States)

    Haigh, S. J.; Hardwick, C. J.; Baldwin, R. E.

    1991-01-01

    A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures.

  19. 8 CFR 333.2 - Attachment of photographs to documents.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Attachment of photographs to documents. 333... PHOTOGRAPHS § 333.2 Attachment of photographs to documents. A signed photograph of the applicant must be... portion of the photograph in such a manner as not to obscure the features of the applicant. [56 FR 50495...

  20. Development of Augmented Spark Impinging Igniter System for Methane Engines

    Science.gov (United States)

    Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

    2017-01-01

    The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. NASA can share technology and expertise under the SAA for the benefit of the CATALYST partners. MSFC seeking to vacuum test Augmented Spark Impinging (ASI) igniter with methane and new exciter units to support CATALYST partners and NASA programs. ASI has previously been used/tested successfully at sea-level, with both O2/CH4 and O2/H2 propellants. Conventional ignition exciter systems historically experienced corona discharge issues in vacuum. Often utilized purging or atmospheric sealing on high voltage lead to remedy. Compact systems developed since PCAD could eliminate the high-voltage lead and directly couple the exciter to the spark igniter. MSFC developed Augmented Spark Impinging (ASI) igniter. Successfully used in several sea-level test programs. Plasma-assisted design. Portion of ox flow is used to generate hot plasma. Impinging flows downstream of plasma. Additional fuel flow down torch tube sleeve for cooling near stoichiometric torch flame. Testing done at NASA GRC Altitude Combustion Stand (ACS) facility 2000-lbf class facility with altitude simulation up to around 100,000 ft. (0.2 psia [10 Torr]) via nitrogen driven ejectors. Propellant conditioning systems can provide temperature control of LOX/CH4 up to test article.

  1. Proton beam monitor chamber calibration

    International Nuclear Information System (INIS)

    Gomà, C; Meer, D; Safai, S; Lorentini, S

    2014-01-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams. (paper)

  2. A small flat fission chamber

    International Nuclear Information System (INIS)

    Li Yijun; Wang Dalun; Chen Suhe

    1999-01-01

    With fission materials of depleted uranium, natural uranium, enriched uranium, 239 Pu, and 237 Np, the authors have designed and made a series of small flat fission chamber. The authors narrated the construction of the fission chamber and its technological process of manufacture, and furthermore, the authors have measured and discussed the follow correct factor, self-absorption, boundary effect, threshold loss factor, bottom scatter and or so

  3. Advances on fission chamber modelling

    International Nuclear Information System (INIS)

    Filliatre, Philippe; Jammes, Christian; Geslot, Benoit; Veenhof, Rob

    2013-06-01

    In-vessel, online neutron flux measurements are routinely performed in mock-up and material testing reactors by fission chambers. Those measurements have a wide range of applications, including characterization of experimental conditions, reactor monitoring and safety. Depending on the application, detectors may experience a wide range of constraints, of several magnitudes, in term of neutron flux, gamma-ray flux, temperature. Hence, designing a specific fission chamber and measuring chain for a given application is a demanding task. It can be achieved by a combination of experimental feedback and simulating tools, the latter being based on a comprehensive understanding of the underlying physics. A computation route that simulates fission chambers, named CHESTER, is presented. The retrieved quantities of interest are the neutron-induced charge spectrum, the electronic and ionic pulses, the mean current and variance, the power spectrum. It relies on the GARFIELD suite, originally developed for drift chambers, and makes use of the MAGBOLTZ code to assess the drift parameters of electrons within the filling gas, and the SRIM code to evaluate the stopping range of fission products. The effect of the gamma flux is also estimated. Computations made with several fission chambers exemplify the possibilities of the route. A good qualitative agreement is obtained when comparing the results with the experimental data available to date. In a near future, a comprehensive experimental programme will be undertaken to qualify the route using the known neutron sources, mock-up reactors and wide choice of fission chambers, with a stress on the predictiveness of the Campbelling mode. Depending on the results, a refinement of the modelling and an effort on the accuracy of input data are also to be considered. CHESTER will then make it possible to predict the overall sensitivity of a chamber, and to optimize the design for a given application. Another benefit will be to increase the

  4. 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.

  5. The OPAL vertex drift chamber

    International Nuclear Information System (INIS)

    Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

    1990-01-01

    A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

  6. Looking for an old aerial photograph

    Science.gov (United States)

    ,

    1997-01-01

    Attempts to photograph the surface of the Earth date from the 1800's, when photographers attached cameras to balloons, kites, and even pigeons. Today, aerial photographs and satellite images are commonplace. The rate of acquiring aerial photographs and satellite images has increased rapidly in recent years. Views of the Earth obtained from aircraft or satellites have become valuable tools to Government resource planners and managers, land-use experts, environmentalists, engineers, scientists, and a wide variety of other users. Many people want historical aerial photographs for business or personal reasons. They may want to locate the boundaries of an old farm or a piece of family property. Or they may want a photograph as a record of changes in their neighborhood, or as a gift. The U.S. Geological Survey (USGS) maintains the Earth Science Information Centers (ESIC?s) to sell aerial photographs, remotely sensed images from satellites, a wide array of digital geographic and cartographic data, as well as the Bureau?s wellknown maps. Declassified photographs from early spy satellites were recently added to the ESIC offerings of historical images. Using the Aerial Photography Summary Record System database, ESIC researchers can help customers find imagery in the collections of other Federal agencies and, in some cases, those of private companies that specialize in esoteric products.

  7. Stephen Marc: Photographer for Our Time

    Science.gov (United States)

    Smith, Toni M. Shorter

    2012-01-01

    It is said that "a picture is worth a thousand words" as visual images can express complex and multilayered ideas. Sometimes photographic imagery is so strong and resonant of certain success, struggles, or events that it becomes key to a community or generation. As historic records, photographs are uniquely able to present not only success and…

  8. 36 CFR 702.4 - Photographs.

    Science.gov (United States)

    2010-07-01

    ... 702.4 Parks, Forests, and Public Property LIBRARY OF CONGRESS CONDUCT ON LIBRARY PREMISES § 702.4 Photographs. (a) The policy set out herein applies to all individuals who are photographing Library of... conditions may include provision for a fee for services rendered consistent with the Library's policies and...

  9. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers

    International Nuclear Information System (INIS)

    Fowler, W.B.

    1989-01-01

    Proton beams, from the 1GeV Cosmotron accelerator at Brookhaven, were used in the 1950s to produce strange particles. One big leap forward technologically was the development of the diffusion cloud chamber which made detecting particle tracks more accurate and sensitive. A large co-operative team worked on its development. By the mid 1950s enough tracks had been observed to show the associated production of strange particles. It was the same Brookhaven workers who developed the eighty-inch hydrogen bubble chamber which took the first photograph of the long predicted omega minus particle at the end of the decade. (UK)

  10. Low temperature spark plasma sintering of YIG powders

    International Nuclear Information System (INIS)

    Fernandez-Garcia, L.; Suarez, M.; Menendez, J.L.

    2010-01-01

    A transition from a low to a high spin state in the magnetization saturation between 1000 and 1100 o C calcination temperature is observed in YIG powders prepared by oxides mixture. Spark plasma sintering of these powders between 900 and 950 o C leads to dense samples with minimal formation of YFeO 3 , opening the way to co-sintering of YIG with metals or metallic alloys. The optical properties depend on the sintering stage: low (high) density samples show poor (bulk) optical absorption.

  11. Spark gap overpressures in the transfer capacitor device

    International Nuclear Information System (INIS)

    Burkhardt, L.C.; Dike, R.S.

    1977-01-01

    A designer of spark gaps is often faced with two gas pressure problems, one static and one dynamic. The former is easy to obtain data on which to base intelligent design specifications; about the latter, less is known. It is the total internal pressure environment we have attempted to measure, in an un-time-resolved way, in order to give the designer some rationale in designing gaps of this category. We measure overpressures of approximately 400 PSI in a 13 cubic inch gap passing currents of approximately 200 kA

  12. Search for an optimum time response of spark counters

    International Nuclear Information System (INIS)

    Devismes, A.; Finck, Ch.; Kress, T.; Gobbi, A.; Eschke, J.; Herrmann, N.; Hildenbrand, K.D.; Koczon, P.; Petrovici, M.

    2002-01-01

    A spark counter of the type developed by Pestov has been tested with the aim of searching for an optimum time response function, changing voltage, content of noble and quencher gases, pressure and energy-loss. Replacing the usual argon by neon has brought an improvement of the resolution and a significant reduction of tails in the time response function. It has been proven that a counter as long as 90 cm can deliver, using neon gas mixture, a time resolution σ<60 ps with about 1% absolute tail and an efficiency of about 90%

  13. Compaction of lithium-silicate ceramics using spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Kubatík, Tomáš František; Lukáč, František; Mušálek, Radek; Brožek, Vlastimil; Stehlíková, K.; Chráska, Tomáš

    2017-01-01

    Roč. 61, č. 1 (2017), s. 40-44 ISSN 0862-5468 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 Keywords : Li2Si2O5 * Li2SiO3 * Spark plasma sintering (SPS) * Quantitative Rietveld refinement * X-ray diffraction (XRD) Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 0.439, year: 2016 http://www.ceramics-silikaty.cz/index.php?page=cs_detail_doi&id=789

  14. PEP quark search proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Parker, S I; Harris, F; Karliner, I; Yount, D [Hawaii Univ., Honolulu (USA); Ely, R; Hamilton, R; Pun, T [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Guryn, W; Miller, D; Fries, R [Northwestern Univ., Evanston, IL (USA)

    1981-04-01

    Proportional chambers are used in the PEP Free Quark Search to identify and remove possible background sources such as particles traversing the edges of counters, to permit geometric corrections to the dE/dx and TOF information from the scintillator and Cerenkov counters, and to look for possible high cross section quarks. The present beam pipe has a thickness of 0.007 interaction lengths (lambdasub(i)) and is followed in both arms each with 45/sup 0/ <= theta <= 135/sup 0/, ..delta..phi=90/sup 0/ by 5 proportional chambers, each 0.0008 lambdasub(i) thick with 32 channels of pulse height readout, and by 3 thin scintillator planes, each 0.003 lambdasub(i) thick. Following this thin front end, each arm of the detector has 8 layers of scintillator (one with scintillating light pipes) interspersed with 4 proportional chambers and a layer of lucite Cerenkov counters. Both the calculated ion statistics and measurements using He-CH/sub 4/ gas in a test chamber indicate that the chamber efficiencies should be >98% for q=1/3. The Landau spread measured in the test was equal to that observed for normal q=1 traversals. One scintillator plane and thin chamber in each arm will have an extra set of ADC's with a wide gate bracketing the normal one so timing errors and tails of earlier pulses should not produce fake quarks.

  15. Effects of tetracaine on voltage-activated calcium sparks in frog intact skeletal muscle fibers.

    Science.gov (United States)

    Hollingworth, Stephen; Chandler, W Knox; Baylor, Stephen M

    2006-03-01

    The properties of Ca(2+) sparks in frog intact skeletal muscle fibers depolarized with 13 mM [K(+)] Ringer's are well described by a computational model with a Ca(2+) source flux of amplitude 2.5 pA (units of current) and duration 4.6 ms (18 degrees C; Model 2 of Baylor et al., 2002). This result, in combination with the values of single-channel Ca(2+) current reported for ryanodine receptors (RyRs) in bilayers under physiological ion conditions, 0.5 pA (Kettlun et al., 2003) to 2 pA (Tinker et al., 1993), suggests that 1-5 RyR Ca(2+) release channels open during a voltage-activated Ca(2+) spark in an intact fiber. To distinguish between one and greater than one channel per spark, sparks were measured in 8 mM [K(+)] Ringer's in the absence and presence of tetracaine, an inhibitor of RyR channel openings in bilayers. The most prominent effect of 75-100 microM tetracaine was an approximately sixfold reduction in spark frequency. The remaining sparks showed significant reductions in the mean values of peak amplitude, decay time constant, full duration at half maximum (FDHM), full width at half maximum (FWHM), and mass, but not in the mean value of rise time. Spark properties in tetracaine were simulated with an updated spark model that differed in minor ways from our previous model. The simulations show that (a) the properties of sparks in tetracaine are those expected if tetracaine reduces the number of active RyR Ca(2+) channels per spark, and (b) the single-channel Ca(2+) current of an RyR channel is normal voltage-activated sparks (i.e., in the absence of tetracaine) are produced by two or more active RyR Ca(2+) channels. The question of how the activation of multiple RyRs is coordinated is discussed.

  16. X-radiography using photographic papers

    International Nuclear Information System (INIS)

    Nitiyaporn, W.

    1986-01-01

    The objective of this research is to study the possibility of using photographic paper, available on the market, for x-ray radiography instead of x-ray film which is more expensive and more complicate to develop. This research concerned about (1) the method and the limitation of x-ray radiography by using 3 types of photographic paper, namely, F2, F3 and F4 distributed by the Kodak Company, as the screen with 3 different kinds of intensifying screens produced by the Phillips Company, Toshiba Company and Picker Company to increase photographic efficiency; (2) correction factor between these 3 types of photographic paper and intensifying screens; (3) the most suitable combination of photographic paper and intensifying screens used; (4) the result of using photographic paper and x-ray film in x-ray radiography regarding quality, cost and film developing. From the research, it was found that (1) the combination of intensifying screen from Picker Company and Kodak photographic paper No. F4 coating with silver bromide with a little mixture of silver iodide resulted in higher sensitivity and more contrast than other combination; (2) photographic papers had more limitation than x-ray film in the sense that it could be used with the iron test piece no thicker than 3 cm.with the x-ray energy of 220 k Vp; (3) photographic papers would give almost the same degree of contrast and sensitivity as x-ray film when used with thin test specimens. For instance the smallest wire No.12 of DIN 62 FE could be seen in the photographic paper at 220 k Vp while it could be seen in the x-ray film at 200 k Vp while it could be seen in the x-ray film at 200 k Vp. The exposure of photographic paper would be in vicinity of x-ray film when it was used with thin test specimens. Photographic paper would produce sharpness definition, density and contrast picture and also details of the picture closely to what given by x-ray film. It is concluded that if the test specimens are thin, photographic papers

  17. Advances in the electro-spark deposition coating process

    International Nuclear Information System (INIS)

    Johnson, R.N.; Sheldon, G.L.

    1986-04-01

    Electro-spark deposition (ESD) is a pulsed-arc micro-welding process using short-duration, high-current electrical pulses to deposit an electrode material on a metallic substrate. It is one of the few methods available by which a fused, metallurgically bonded coating can be applied with such a low total heat input that the bulk substrate material remains at or near ambient temperatures. The short duration of the electrical pulse allows an extremely rapid solidification of the deposited material and results in an exceptionally fine-grained, homogenous coating that approaches (and with some materials, actually is) an amorphous structure. This structure is believed to contribute to the good tribological and corrosion performance observed for hardsurfacing materials used in the demanding environments of high temperatures, liquid metals, and neutron irradiation. A brief historical review of the process is provided, followed by descriptions of the present state-of-the-art and of the performance and applications of electro-spark deposition coatings in liquid-metal-cooled nuclear reactors

  18. Observations of dense plasma formation in the vacuum spark

    International Nuclear Information System (INIS)

    Chuaqui, H.; Favre, M.; Wyndham, E.; Aliaga R, R.; Choi, P.; Dumitrescu-Zoita, C.

    1994-01-01

    A series of experimental observations have been performed on the dense plasma formations or Hot Spots generated in the Vacuum Spark. The plasma discharges are driven by a 1.5 Ohm, 120 ns line at currents up to 100 KA. The line may be used to deliver a rectangular current pulse when the line gap is used. Alternatively when the line gap is shorted, the Vacuum Spark itself switches the line. A Nd: Yag Laser, with an energy of 0.5 J in an 8 ns pulse, is used to pre ionizing the discharge. The formation of Hot Spots is studied under a range of different conditions. These include the pre ionizing conditions, as well as the Anode shape and the Anode Cathode separation. The optimization of these parameters permit very reproducible shot to shot behaviour. Of particular interest is the Hot Spot size dependence as a function of its temperature and of time. The use of a new variant on the Pin Hole Camera, the Slit Wire Camera provides a new method of measuring with precision the Hot Spot dimensions in different X-ray emission energy ranges. A quadruple hole Camera is used to measure the temperature of the Hot Spots. The temporal and spatial evolution of the X-ray emission is measured using using a Slit Wire, Scintillator, Fibre Optic, Photomultiplier array. The temporal emission of the X-rays is also observed using an array of PIN X-ray diodes. (author). 5 refs, 6 figs

  19. Exploratory studies on a passively triggered vacuum spark

    Energy Technology Data Exchange (ETDEWEB)

    Rout, R.K. [High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai (India)]. E-mail: rkrout@apsara.barc.ernet.in; Auluck, S.K.H.; Kulkarni, L.V. [High Pressure Physics Division, Bhabha Atomic Research Centre, Mumbai, India (India); Nagpal, J.S. [Radiation Standards and Instrumentation Division, Bhabha Atomic Research Centre, Mumbai (India)

    1999-12-07

    The results of an experimental investigation on a passively triggered vacuum spark device are presented. The diagnostics include the current, x-ray and optical emission measurements. The sharp dips in the current derivative signal indicate the occurrence of pinching at an early stage of the discharge (at current {approx} 5 kA). A well-confined plasma with a central hot region was recorded using a streak camera. The pinched plasma was observed to undergo kink-type oscillations with a time period of 10-15 ns. Repeated plasma fronts were seen to move from the anode to the cathode with an average velocity of {approx}5x10{sup 6} cm s{sup -1}. Soft x-ray emission having a radiation intensity of a few hundred mR per discharge was observed. The x-ray signals obtained using photodiodes showed multiple bursts. A soft x-ray pinhole camera recorded micro-pinches of {approx}100 {mu}m. The x-ray emitting regions were confined to the inter-electrode gap. The x-ray emission characteristics were influenced by the electrolytic resistance, which was connected across the spark gap to initiate discharge. (author)

  20. Exploratory studies on a passively triggered vacuum spark

    Science.gov (United States)

    Rout, R. K.; Auluck, S. K. H.; Nagpal, J. S.; Kulkarni, L. V.

    1999-12-01

    The results of an experimental investigation on a passively triggered vacuum spark device are presented. The diagnostics include the current, x-ray and optical emission measurements. The sharp dips in the current derivative signal indicate the occurrence of pinching at an early stage of the discharge (at current icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>5 kA). A well-confined plasma with a central hot region was recorded using a streak camera. The pinched plasma was observed to undergo kink-type oscillations with a time period of 10-15 ns. Repeated plasma fronts were seen to move from the anode to the cathode with an average velocity of icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>5 × 106 cm s-1. Soft x-ray emission having a radiation intensity of a few hundred mR per discharge was observed. The x-ray signals obtained using photodiodes showed multiple bursts. A soft x-ray pinhole camera recorded micro-pinches of icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>100 µm. The x-ray emitting regions were confined to the inter-electrode gap. The x-ray emission characteristics were influenced by the electrolytic resistance, which was connected across the spark gap to initiate discharge.

  1. Influence of hydrox on spark ignition engine performance

    International Nuclear Information System (INIS)

    Naude, A.F.

    2003-01-01

    An experimental investigation was performed on the influence of the addition of small quantities of Hydrox (hydrogen and oxygen) as generated through electrolysis of water on the performance of a spark ignition engine. A Mazda 1600 cc fuel injected engine connected to a Superflow SF901 dynamometer system was used in this project. The engine was also equipped with a Unichip engine management system in order to enable changes in the spark timing and the amount of fuel injected. Hydrox was generated by an electrolysis process that could either be powered by the engine's alternator or from a separate power source. This hydrox gas produced from the electrolyzer was introduced into the engine's intake manifold and the influence of this was measured on the engine's performance, emissions and fuel consumption. For these tests a typical load condition as experienced for a light passenger car vehicle driven at 100 km/h on the open road was simulated. Typical results for the change in emissions with the hydrox introduction showed a significant reduction in hydrocarbons at lean air-fuel ratio operation of the engine. Additionally with the electrolysis process being driven by the engine a small improvement in fuel consumption was experienced. (author)

  2. Air spark-like plasma source for antimicrobial NOx generation

    International Nuclear Information System (INIS)

    Pavlovich, M J; Galleher, C; Curtis, B; Clark, D S; Graves, D B; Ono, T; Machala, Z

    2014-01-01

    We demonstrate and analyse the generation of nitrogen oxides and their antimicrobial efficacy using atmospheric air spark-like plasmas. Spark-like discharges in air in a 1 L confined volume are shown to generate NO x at an initial rate of about 1.5  ×  10 16 NO x molecules/J dissipated in the plasma. Such a discharge operating in this confined volume generates on the order of 6000 ppm NO x in 10 min. Around 90% of the NO x is in the form of NO 2 after several minutes of operation in the confined volume, suggesting that NO 2 is the dominant antimicrobial component. The strong antimicrobial action of the NO x mixture after several minutes of plasma operation is demonstrated by measuring rates of E. coli disinfection on surfaces and in water exposed to the NO x mixture. Some possible applications of plasma generation of NO x (perhaps followed by dissolution in water) include disinfection of surfaces, skin or wound antisepsis, and sterilization of medical instruments at or near room temperature. (paper)

  3. A new and efficient mechanism for spark ignition engines

    International Nuclear Information System (INIS)

    Shadloo, M.S.; Poultangari, R.; Abdollahzadeh Jamalabadi, M.Y.; Rashidi, M.M.

    2015-01-01

    Highlights: • A new slider–crank mechanism, with superior performance is presented. • Thermodynamic processes as well as vibration and internal forces have been modeled. • Comparison with the conventional four-stroke spark ignition engines is made. • Advantages and disadvantages of the proposed mechanism are discussed. - Abstract: In this paper a new symmetrical crank and slider mechanism is proposed and a zero dimensional model is utilized to study its combustion performance enhancement in a four-stroke spark ignition (SI) engine. The main features of this new mechanism are superior thermodynamic efficiency, lower internal frictions, and lower pollutants. Comparison is made between its performance and that of the conventional four-stroke SI engines. Presented mechanism is designed to provide better fuel consumption of internal combustion engines. These advantages over standard engine are achieved through synthesis of new mechanism. Numerical calculation have been performed for several cases of different mechanism parameters, compression ratio and engine speed. A comprehensive comparison between their thermodynamic processes as well as vibration and internal forces has been done. Calculated efficiency and power diagrams are plotted and compared with performance of a conventional SI engine. Advantages and disadvantages of the proposed mechanism are discussed in details

  4. Spark and HPC for High Energy Physics Data Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Sehrish, Saba; Kowalkowski, Jim; Paterno, Marc

    2017-05-01

    A full High Energy Physics (HEP) data analysis is divided into multiple data reduction phases. Processing within these phases is extremely time consuming, therefore intermediate results are stored in files held in mass storage systems and referenced as part of large datasets. This processing model limits what can be done with interactive data analytics. Growth in size and complexity of experimental datasets, along with emerging big data tools are beginning to cause changes to the traditional ways of doing data analyses. Use of big data tools for HEP analysis looks promising, mainly because extremely large HEP datasets can be represented and held in memory across a system, and accessed interactively by encoding an analysis using highlevel programming abstractions. The mainstream tools, however, are not designed for scientific computing or for exploiting the available HPC platform features. We use an example from the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) in Geneva, Switzerland. The LHC is the highest energy particle collider in the world. Our use case focuses on searching for new types of elementary particles explaining Dark Matter in the universe. We use HDF5 as our input data format, and Spark to implement the use case. We show the benefits and limitations of using Spark with HDF5 on Edison at NERSC.

  5. Directional muon jet chamber for a muon collider (Groovy Chamber)

    International Nuclear Information System (INIS)

    Atac, M.

    1996-10-01

    A directional jet drift chamber with PAD readout is proposed here which can select vertex originated muons within a given time window and eliminate those muons which primarily originate upstream, using only a PAD readout. Drift time provides the Z-coordinate, and the center of gravity of charge distribution provides the r-ψ coordinates. Directionality at the trigger level is obtained by the timing measurement from the PAD hits within a given time window. Because of the long drift time between the bunch crossings, a muon collider enables one to choose a drift distance in the drift chamber as long as 50 cm. This is an important factor in reducing cost of drift chambers which have to cover relatively large areas

  6. Agreement between radiographic and photographic trabecular patterns

    International Nuclear Information System (INIS)

    Korstjens, C.M.; Geraets, W.G.M.; Stelt, P.F. van der; Spruijt, R.J.; Mosekilde, L.

    1998-01-01

    Purpose: It has been hypothesized that photographs can facilitate the interpretation of the radiographic characteristics of trabecular bone. The reliability of these photographic and radiographic approaches has been determined, as have various agreements between the two approaches and their correlations with biomechanical characteristics. Material and Methods: Fourteen vertebral bodies were obtained at autopsy from 6 women and 8 men aged 22-76 years. Photographs (n=28) and radiographs (n=28) were taken of midsagittal slices from the third lumbar vertebra. The radiographs and photographs were digitized and the geometric properties of the trabecular architecture were then determined with a digital images analysis technique. Information on the compressive strength and ash density of the vertebral body was also available. Results: The geometric properties of both radiographs and photographs could be measured with a high degree of reliability (Cronbach's α>0.85). Agreement between the radiographic and photographic approaches was mediocre as only the radiographic measurements showed insignificant correlations (p<0.05) with the biomechanical characteristics. We suggest that optical phenomena may result in the significant correlations between the photographs and the biomechanical characteristics. Conclusion: For digital image processing, radiography offers a superior description of the architecture of trabecular bone to that offered by photography. (orig.)

  7. Agreement between radiographic and photographic trabecular patterns

    Energy Technology Data Exchange (ETDEWEB)

    Korstjens, C.M.; Geraets, W.G.M.; Stelt, P.F. van der [Dept. of Oral Radiology, Academic Centre for Dentistry, Amsterdam (Netherlands); Spruijt, R.J. [Div. of Psychosocial Research and Epidemiology, Netherlands Cancer Inst., Amsterdam (Netherlands); Mosekilde, L. [Dept. of Cell Biology, Univ. of Aarhus (Denmark)

    1998-11-01

    Purpose: It has been hypothesized that photographs can facilitate the interpretation of the radiographic characteristics of trabecular bone. The reliability of these photographic and radiographic approaches has been determined, as have various agreements between the two approaches and their correlations with biomechanical characteristics. Material and Methods: Fourteen vertebral bodies were obtained at autopsy from 6 women and 8 men aged 22-76 years. Photographs (n=28) and radiographs (n=28) were taken of midsagittal slices from the third lumbar vertebra. The radiographs and photographs were digitized and the geometric properties of the trabecular architecture were then determined with a digital images analysis technique. Information on the compressive strength and ash density of the vertebral body was also available. Results: The geometric properties of both radiographs and photographs could be measured with a high degree of reliability (Cronbach`s {alpha}>0.85). Agreement between the radiographic and photographic approaches was mediocre as only the radiographic measurements showed insignificant correlations (p<0.05) with the biomechanical characteristics. We suggest that optical phenomena may result in the significant correlations between the photographs and the biomechanical characteristics. Conclusion: For digital image processing, radiography offers a superior description of the architecture of trabecular bone to that offered by photography. (orig.)

  8. Plasma chemistry in wire chambers

    International Nuclear Information System (INIS)

    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 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

  9. The optimization of some of the conditions for analysis by spark-source mass spectrometry

    International Nuclear Information System (INIS)

    Pearton, D.C.P.; Sobiecki, A.

    1980-01-01

    The need for improved precision in spark-source mass spectrometry is highlighted. Several parameters, such as photoplate-development technique, instrumental stability and focus, and sparking conditions, were optimized. Measurements made under these optimum conditions attained precisions of more than 12 per cent

  10. Development of spark cathode E-guns. Draft final reprt, Phase I, July--October 1978

    International Nuclear Information System (INIS)

    Loda, G.; Lindstrand, R.

    1979-01-01

    A 12 sided spark cathode is designed and constructed to replace the bladed, cold cathode structure in the electron gun of the Los Alamos Scientific Laboratory Antares prototype power amplifier. Design work includes computer modeling and full scale low voltage modeling. Life testing to 100,000 pulses is documented. The spark cathode offers precise control of emission site location and a high reliability

  11. 2-Methylfuran: A bio-derived octane booster for spark-ignition engines

    KAUST Repository

    Sarathy, Mani; Shankar, Vijai; Tripathi, Rupali; Pitsch, Heinz; Sarathy, Mani

    2018-01-01

    The efficiency of spark-ignition engines is limited by the phenomenon of knock, which is caused by auto-ignition of the fuel-air mixture ahead of the spark-initiated flame front. The resistance of a fuel to knock is quantified by its octane index

  12. Automated qualification and analysis of protective spark gaps for DC accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Srutarshi; Rajan, Rehim N.; Dewangan, S.; Sharma, D.K.; Patel, Rupesh; Bakhtsingh, R.I.; Gond, Seema; Waghmare, Abhay; Thakur, Nitin; Mittal, K.C. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    Protective spark gaps are used in the high voltage multiplier column of a 3 MeV DC Accelerator to prevent excessive voltage build-ups. Precise gap of 5 mm is maintained between the electrodes in these spark gaps for obtaining 120 kV± 5 kV in 6 kg/cm{sup 2} SF{sub 6} environment which is the dielectric medium. There are 74 such spark gaps used in the multiplier. Each spark gap has to be qualified for electrical performance before fitting in the accelerator to ensure reliable operation. As the breakdown voltage stabilizes after a large number of sparks between the electrodes, the qualification process becomes time consuming and cumbersome. For qualifying large number of spark gaps an automatic breakdown analysis setup has been developed. This setup operates in air, a dielectric medium. The setup consists of a flyback topology based high voltage power supply with maximum rating of 25 kV. This setup works in conjunction with spark detection and automated shutdown circuit. The breakdown voltage is sensed using a peak detector circuit. The voltage breakdown data is recorded and statistical distribution of the breakdown voltage has been analyzed. This paper describes details of the diagnostics and the spark gap qualification process based on the experimental data. (author)

  13. [Natural head position's reproducibility on photographs].

    Science.gov (United States)

    Eddo, Marie-Line; El Hayeck, Émilie; Hoyeck, Maha; Khoury, Élie; Ghoubril, Joseph

    2017-12-01

    The purpose of this study is to evaluate the reproducibility of natural head position with time on profile photographs. Our sample is composed of 96 students (20-30 years old) at the department of dentistry of Saint Joseph University in Beirut. Two profile photographs were taken in natural head position about a week apart. No significant differences were found between T0 and T1 (E = 1.065°). Many studies confirmed this reproducibility with time. Natural head position can be adopted as an orientation for profile photographs in orthodontics. © EDP Sciences, SFODF, 2017.

  14. The Photoshop CS4 Companion for Photographers

    CERN Document Server

    Story, Derrick

    2009-01-01

    "Derrick shows that Photoshop can be friendly as well as powerful. In part, he does that by focusing photographers on the essential steps of an efficient workflow. With this guide in hand, you'll quickly learn how to leverage Photoshop CS4's features to organize and improve your pictures."-- John Nack, Principal Product Manager, Adobe Photoshop & BridgeMany photographers -- even the pros -- feel overwhelmed by all the editing options Photoshop provides. The Photoshop CS4 Companion for Photographers pares it down to only the tools you'll need most often, and shows you how to use those tools as

  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. An experimental propane bubble chamber

    International Nuclear Information System (INIS)

    Rogozinski, A.

    1957-01-01

    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) [fr

  17. Equipment for handling ionization chamber

    International Nuclear Information System (INIS)

    Altmann, J.

    1988-01-01

    The device consists of an ionization channel with an ionization chamber, of a support ring, axial and radial bearings, a sleeve, a screw gear and an electric motor. The ionization chamber is freely placed on the bottom of the ionization channel. The bottom part of the channel deviates from the vertical axis. The support ring propped against the axial bearing in the sleeve is firmly fixed to the top part of the ionization channel. The sleeve is fixed to the reactor lid. Its bottom part is provided with a recess for the radial bearing which is propped against a screw wheel firmly connected to the ionization channel. In measuring neutron flux, the screw wheel is rotated by the motor, thus rotating the whole ionization channel such that the ionization chamber is displaced into the reactor core.(J.B.). 1 fig

  18. General purpose nuclear irradiation chamber

    International Nuclear Information System (INIS)

    Nurul Fadzlin Hasbullah; Nuurul Iffah Che Omar; Nahrul Khair Alang Md Rashid; Jaafar Abdullah

    2013-01-01

    Nuclear technology has found a great need for use in medicine, industry, and research. Smoke detectors in our homes, medical treatments and new varieties of plants by irradiating its seeds are just a few examples of the benefits of nuclear technology. Portable neutron source such as Californium-252, available at Industrial Technology Division (BTI/ PAT), Malaysian Nuclear Agency, has a 2.645 year half-life. However, 252 Cf is known to emit gamma radiation from the source. Thus, this chamber aims to provide a proper gamma shielding for samples to distinguish the use of mixed neutron with gamma-rays or pure neutron radiation. The chamber is compatible to be used with other portable neutron sources such as 241 Am-Be as well as the reactor TRIGA PUSPATI for higher neutron dose. This chamber was designed through a collaborative effort of Kulliyyah Engineering, IIUM with the Industrial Technology Division (BTI) team, Malaysian Nuclear Agency. (Author)

  19. Holography in small bubble chambers

    International Nuclear Information System (INIS)

    Lecoq, P.

    1984-01-01

    This chapter reports on an experiment to determine the total charm cross section at different incident momenta using the small, heavy liquid bubble chamber HOBC. Holography in liquid hydrogen is also tested using the holographic lexan bubble chamber HOLEBC with the aim of preparing a future holographic experiment in hydrogen. The high intensity tests show that more than 100 incident tracks per hologram do not cause a dramatic effect on the picture quality. Hydrogen is more favorable than freon as the bubble growth is much slower in hydrogen. An advantage of holography is to have the maximum resolution in the full volume of the bubble chamber, which allows a gain in sensitivity by a factor of 10 compared to classical optics as 100 tracks per hologram look reasonable. Holograms are not more difficult to analyze than classical optics high-resolution pictures. The results show that holography is a very powerful technique which can be used in very high resolution particle physics experiments

  20. SciSpark: Highly Interactive and Scalable Model Evaluation and Climate Metrics for Scientific Data and Analysis

    Data.gov (United States)

    National Aeronautics and Space Administration — We will construct SciSpark, a scalable system for interactive model evaluation and for the rapid development of climate metrics and analyses. SciSpark directly...

  1. A new spark detection system for the electrostatic septa of the SPS North (experimental) Area

    CERN Multimedia

    Barlow, R A; Borburgh, J; Carlier, E; Chanavat, C; Pinget, B

    2013-01-01

    Electrostatic septa (ZS) are used in the extraction of the particle beams from the CERN SPS to the North Area experimental zone. These septa employ high electric fields, generated from a 300 kV power supply, and are particularly prone to internal sparking around the cathode structure. This sparking degrades the electric field quality, consequently affecting the extracted beam, vacuum and equipment performance. To mitigate these effects, a Spark Detection System (SDS) has been realised, which is based on an industrial SIEMENS S7-400 programmable logic controller and deported Boolean processors modules interfaced through a PROFINET fieldbus. The SDS interlock logic uses a moving average spark rate count to determine if the ZS performance is acceptable. Below a certain spark rate it is probable that the ZS septa tank vacuum can recover, thus avoiding transition into a\

  2. Performance Characteristics Comparison of CNG Port and CNG Direct Injection in Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Rajesh Patel

    2018-03-01

    Full Text Available A comparative performance analysis is being carried out on a four cylinder, four stroke cycle, spark ignition engine having displacement volume 1297cc. The cylinder head of original gasoline based engine was modified by drilling holes from upper surfaces of head to individual combustion chamber to convert the engine in a CNG direct injection engine. The CNG port injection (CNG-PI system and CNG direct injection (CNG-DI system were incorporated with the single engine.  The engine was retrofitted to run on both CNG-PI and CNG-DI system alternately with common CNG tank and other engine loading and measurement system. The engine was equipped with electrical dynamometer having rheostat type loading. The CNG direct injection system was incorporated with various sensors and engine ECU. The operating parameters can be obtained on computer screen by loading the computer with engine through switch box. The engine was run over the speed range of 1000 rpm to 3000 rpm with incremental speed of 300 rpm. The performance parameters were calculated from observations and recorded for both CNG-PI and CNG-DI system. The experimental investigation exhibits that, the average 7-8% reduction in BSFC while the engine was running with CNG-DI system as compared to that of CNG-PI system. Also the engine produced 8-9% higher brake torque and hence higher brake power. The engine gives 6-7% higher brake thermal efficiency with CNG-DI system as compared to CNG-PI system.

  3. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  4. Laboratory Course on Drift Chambers

    International Nuclear Information System (INIS)

    Garcia-Ferreira, Ix-B.; Garcia-Herrera, J.; Villasenor, L.

    2006-01-01

    Drift chambers play an important role in particle physics experiments as tracking detectors. We started this laboratory course with a brief review of the theoretical background and then moved on to the the experimental setup which consisted of a single-sided, single-cell drift chamber. We also used a plastic scintillator paddle, standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. During the laboratory session the students performend measurements of the following quantities: a) drift velocities and their variations as function of the drift field; b) gas gains and c) diffusion of electrons as they drifted in the gas

  5. The knife-edge chamber

    International Nuclear Information System (INIS)

    Barasch, E.F.; Bowcock, T.J.V.; Drew, M.M.; Elliott, S.M.; Lee, B.; McIntyre, P.M.; Pang, Y.; Popovic, M.; Smith, D.D.

    1990-01-01

    In this paper the design for a new technology for particle track detectors is described. Using standard IC fabrication techniques, a pattern of microscopic knife edges and field-shaping electrodes can be fabricated on a silicon substrate. The knife-edge chamber uniquely offers attractive performance for the track chambers required for SSC detectors, for which no present technology is yet satisfactory. Its features include: excellent radiation hardness (10 Mrad), excellent spatial resolution (∼20 μm), short drift time (20 ns), and large pulse height (1 mV)

  6. Ionization chambers for LET determination

    DEFF Research Database (Denmark)

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

    2010-01-01

    resolution and high sensitivity are necessary. For exact dosimetry which is done using ionization chambers (ICs), the recombination taking place in the IC has to be known. Up to now, recombination is corrected phenomenologically and more practical approaches are currently used. Nevertheless, Jaff´e's theory...... of columnar recombination was designed to model the detector efficiency of an ionization chamber. Here, we have shown that despite the approximations and simplification made, the theory is correct for the LETs typically found in clinical radiotherapy employing particles from protons to carbon ions...

  7. The Mark III vertex chamber

    International Nuclear Information System (INIS)

    Adler, J.; Bolton, T.; Bunnell, K.

    1987-07-01

    The design and construction of the new Mark III vertex chamber is described. Initial tests with cosmic rays prove the ability of track reconstruction and yield triplet resolutions below 50 μm at 3 atm using argon/ethane (50:50). Also performed are studies using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. Spatial resolution of 35mm was obtained using dimethyl ether (DME) at 1 atm and 30 μm using argon/ethane (50/50 mixture) at 4 atm. Preliminary studies indicate the DME to adversely affect such materials as aluminized Mylar and Delrin

  8. Controlling spark timing for consecutive cycles to reduce the cyclic variations of SI engines

    International Nuclear Information System (INIS)

    Kaleli, Alirıza; Ceviz, Mehmet Akif; Erenturk, Köksal

    2015-01-01

    Minimization of the cyclic variations is one of the most important design goal for spark-ignited engines. Primary motivation of this study is to reduce the cyclic variations in spark ignition engines by controlling the spark timing for consecutive cycles. A stochastic model was performed between spark timing and in–cylinder maximum pressure by using the system identification techniques. The incylinder maximum pressure of the next cycle was predicted with this model. Minimum variance and generalized minimum variance controllers were designed to regulate the in–cylinder maximum pressure by changing the spark timing for consecutive cycles of the test engine. The produced control algorithms were built in LabView environment and installed to the Field Programmable Gate Arrays (FPGA) chassis. According to the test results, the in–cylinder maximum pressure of the next pressure cycle can be predicted fairly well, and the spark timing can be regulated to keep the in–cylinder maximum pressure in a desired band to reduce the cyclic variations. At fixed spark timing experiments, the COV Pmax and COV imep were 3.764 and 0.677%, whereas they decreased to 3.208 and 0.533% when GMV controller was applied, respectively. - Highlights: • Cycle per cycle spark timing control was carried out. • A stochastic process model was described between P max and the spark timing. • The cyclic variations in P max was decreased by keeping it in a desired band. • Different controllers were used to adjust spark timing signal of the next cycle. • COV Pmax was decreased by about 15% by using GMV controller

  9. New ISO standard - personnel photographic film dosemeters

    International Nuclear Information System (INIS)

    Brabec, D.

    1980-01-01

    The ISO Standard 1757 ''Personnel Photographic Film Dosemeters'', issued in June 1980, is briefly described. UVVVR's own dosemeter developed for use in the national film dosimetry service in Czechoslovakia is evaluated in relation to this ISO Standard. (author)

  10. Special photographic emulsions for high LET dosimetry

    International Nuclear Information System (INIS)

    Katz, R.

    1978-12-01

    The purpose of these investigations into photographic emulsion dosimetry is to attempt to use the photographic emulsion to mimic the response of human tissues to high LET radiations. The program therefore requires that a systematic understanding of the response of mammalian cells to ionizing radiations be achieved. We have been concerned with differences in RBE and in radiation response to both high and LET radiations, and in the interrelationship between observations with these different radiations

  11. Development of microwave-enhanced spark-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Ikeda, Yuji; Moon, Ahsa; Kaneko, Masashi

    2010-01-01

    We propose microwave-enhanced spark-induced breakdown spectroscopy with the same measurement and analysis processes as in laser-induced breakdown spectroscopy, but with a different plasma generation mechanism. The size and lifetime of the plasma generated can contribute to increased measurement accuracy and expand its applicability to industrial measurement, such as an exhaust gas analyzer for automobile engine development and its regulation, which has been hard to operate by laser at an engineering evaluation site. The use of microwaves in this application helps lower the cost, reduce the system size, and increase the ease of operation to make it commercially viable. A microwave frequency of 2.45 GHz was used to enhance the volume and lifetime of the plasma at atmospheric condition even at elevated pressure.

  12. Overvoltage protection by point-plane spark gaps

    International Nuclear Information System (INIS)

    Scarlett, W.R.; Riepe, K.B.

    1979-01-01

    In electron-beam-controlled discharge CO 2 lasers, such as those used in the Antares and Helios laser-fusion drivers at the Los Alamos Scientific Laboratory (LASL), protection needs to be provided against possible damage due to overvoltage. A passive (self-breakdown) point-plane spark gap has been developed and successfully used in the Helios power amplifiers which operate at voltages up to 300 kV. A gap of similar design is planned for use in the Antares power amplifiers which operate at 550 kV. These gaps must reliably hold off the normal discharge voltage, but break down with short delay if overvoltaged, diverting the discharge energy to a resistor. A prototype of the Antares gap has been built and is undergoing tests. Parameters being investigated include voltage polarity, gap spacing, gas composition, and gas pressure. Results of these measurements and the operational experience of the Helios gaps will be presented

  13. The Spark of Life: Darwin and the Primeval Soup

    Science.gov (United States)

    Zimmer, Carl

    It's possible that within a decade, a space probe may swing into orbit around Europa and hurl a drill-tipped robot into its icy crust. If that turns out to be the case, no one will watch its performance more anxiously than Christopher Wills and Jeffrey Bada, the coauthors of The Spark of Life. As Europa orbits around Jupiter, the giant planet's gravity exerts enormous tidal forces on the moon with clock-like regularity-forces that Wills and Bada predict should create an environment favorable to the origin of life. If the probe does uncover some kind of indigenous life on Europa, it may bolster the central claim of this intriguing book: that similar processes made life possible on our own planet.

  14. A prediction study of a spark ignition supercharged hydrogen engine

    International Nuclear Information System (INIS)

    Al-Baghdadi, Maher A.R. Sadiq.; Al-Janabi, Haroun A.K. Shahad

    2003-01-01

    Hydrogen is found to be a suitable alternative fuel for spark ignition engines with certain drawbacks, such as high NO x emission and small power output. However, supercharging may solve such problems. In this study, the effects of equivalence ratio, compression ratio and inlet pressure on the performance and NO x emission of a four stroke supercharged hydrogen engine have been analyzed using a specially developed computer program. The results are verified and compared with experimental data obtained from tests on a Ricardo E6/US engine. A chart specifying the safe operation zone of the hydrogen engine has been produced. The safe operation zone means no pre-ignition, acceptable NO x emission, high engine efficiency and lower specific fuel consumption in comparison with the gasoline engine. The study also shows that supercharging is a more effective method to increase the output of a hydrogen engine rather than increasing the compression ratio of the engine at the knock limited equivalence ratio

  15. Quasi-spherical compression of a spark-channel plasma

    International Nuclear Information System (INIS)

    Panarella, E.

    1980-01-01

    An axial spark channel in deuterium has been used as a target for implosive shock waves created with a conventional cylindrical theta-pinch device. The compression of the channel by the implosive waves raised the plasma electron temperature to approximately 120 eV for approximately 6 kJ of condenser bank energy and 1 Torr initial gas pressure. In order to improve the efficiency of compression of the channel plasma and to reduce the end losses inherent in the cylindrical configuration, the theta-pinch geometry was then converted from cylindrical into spherical. Under identical conditions of gas pressure and condenser bank energy, the electron temperature now peaked at approximately 400 eV. When the bank energy was increased to approximately 10 kJ, neutron production was observed. The total neutron output per shot ranged from 10 5 to 10 6 and increased inversely with the pinch discharge volume

  16. Parallel combinations of pre-ionized low jitter spark gaps

    International Nuclear Information System (INIS)

    Fitzsimmons, W.A.; Rosocha, L.A.

    1979-01-01

    The properties of 10 to 30 kV four electrode field emission pre-ionized triggered spark gaps have been studied. A mid-plane off-axis trigger electrode is biased at +V 0 /2, and a field emission point is located adjacent to and biased at the grounded cathode potential. Simultaneous application of a -V 0 trigger rapid pulse to both the electrodes results in the rapid sequential closing of the anode-trigger and trigger-cathode gaps. The observed jitter is about 1.5 ns. Parallel operation of these gaps (up to 10 so far) connected to a common capacitive load has been studied. A simple theory that predicts the number of gaps that may be expected to operate in parallel is discussed

  17. Research on personalized recommendation algorithm based on spark

    Science.gov (United States)

    Li, Zeng; Liu, Yu

    2018-04-01

    With the increasing amount of data in the past years, the traditional recommendation algorithm has been unable to meet people's needs. Therefore, how to better recommend their products to users of interest, become the opportunities and challenges of the era of big data development. At present, each platform enterprise has its own recommendation algorithm, but how to make efficient and accurate push information is still an urgent problem for personalized recommendation system. In this paper, a hybrid algorithm based on user collaborative filtering and content-based recommendation algorithm is proposed on Spark to improve the efficiency and accuracy of recommendation by weighted processing. The experiment shows that the recommendation under this scheme is more efficient and accurate.

  18. Distributed Parallel Endmember Extraction of Hyperspectral Data Based on Spark

    Directory of Open Access Journals (Sweden)

    Zebin Wu

    2016-01-01

    Full Text Available Due to the increasing dimensionality and volume of remotely sensed hyperspectral data, the development of acceleration techniques for massive hyperspectral image analysis approaches is a very important challenge. Cloud computing offers many possibilities of distributed processing of hyperspectral datasets. This paper proposes a novel distributed parallel endmember extraction method based on iterative error analysis that utilizes cloud computing principles to efficiently process massive hyperspectral data. The proposed method takes advantage of technologies including MapReduce programming model, Hadoop Distributed File System (HDFS, and Apache Spark to realize distributed parallel implementation for hyperspectral endmember extraction, which significantly accelerates the computation of hyperspectral processing and provides high throughput access to large hyperspectral data. The experimental results, which are obtained by extracting endmembers of hyperspectral datasets on a cloud computing platform built on a cluster, demonstrate the effectiveness and computational efficiency of the proposed method.

  19. COMPACTION OF LITHIUM-SILICATE CERAMICS USING SPARK PLASMA SINTERING

    Directory of Open Access Journals (Sweden)

    Tomas Frantisek Kubatik

    2016-12-01

    Full Text Available This paper deals with the compaction of ceramics based on lithium-silicate by spark plasma sintering (SPS. The initial powder was prepared by calcination in a resistance furnace at a temperature of 1300 °C with the ratio of Li/Si = 1. Compacting by SPS was carried out at temperatures of 800 - 1000 °C with a maximum pressure of 80 MPa. Samples with open porosity of less than 1 % were prepared at the temperature of 1000 °C. According to the quantitative Rietveld refinement of x-ray diffraction data, the dominant phases in all samples were Li₂Si₂O₅ and Li₂SiO₃, together representing over 80 wt. % of the sintered material.

  20. ZrB₂-CNTs Nanocomposites Fabricated by Spark Plasma Sintering.

    Science.gov (United States)

    Jin, Hua; Meng, Songhe; Xie, Weihua; Xu, Chenghai; Niu, Jiahong

    2016-11-29

    ZrB₂-based nanocomposites with and without carbon nanotubes (CNTs) as reinforcement were prepared at 1600 °C by spark plasma sintering. The effects of CNTs on the microstructure and mechanical properties of nano-ZrB₂ matrix composites were studied. The results indicated that adding CNTs can inhibit the abnormal grain growth of ZrB₂ grains and improve the fracture toughness of the composites. The toughness mechanisms were crack deflection, crack bridging, debonding, and pull-out of CNTs. The experimental results of the nanograined ZrB₂-CNTs composites were compared with those of the micro-grained ZrB₂-CNTs composites. Due to the small size and surface effects, the nanograined ZrB₂-CNTs composites exhibited stronger mechanical properties: the hardness, flexural strength and fracture toughness were 18.7 ± 0.2 GPa, 1016 ± 75 MPa, and 8.5 ± 0.4 MPa·m 1/2 , respectively.

  1. Quartz crystal reinforced quartz glass by spark plasma sintering

    International Nuclear Information System (INIS)

    Torikai, D.; Barazani, B.; Ono, E.; Santos, M.F.M.; Suzuki, C.K.

    2011-01-01

    The Spark Plasma Sintering presents fast processing time when compared to conventional sintering techniques. This allows to control the grain growth during sintering as well as the diffusion rate of a multi-material compounds, and make possible obtainment of functionally graded materials and nanostructured compounds. Powders of high purity silica glass and crystalline silica were sintered in a SPS equipment at temperatures around 1350° C, i.e., above the softening temperature of silica glass and below the melting temperature of quartz crystal. As a result, glass ceramics with pure silica glass matrix reinforced with crystalline alpha-quartz grains were fabricated at almost any desired range of composition, as well as controlled size of the crystalline reinforcement. X-ray diffraction and density measurements showed the possibility to manufacture a well controlled density and crystallinity glass-ceramic materials. (author)

  2. Human resource recommendation algorithm based on ensemble learning and Spark

    Science.gov (United States)

    Cong, Zihan; Zhang, Xingming; Wang, Haoxiang; Xu, Hongjie

    2017-08-01

    Aiming at the problem of “information overload” in the human resources industry, this paper proposes a human resource recommendation algorithm based on Ensemble Learning. The algorithm considers the characteristics and behaviours of both job seeker and job features in the real business circumstance. Firstly, the algorithm uses two ensemble learning methods-Bagging and Boosting. The outputs from both learning methods are then merged to form user interest model. Based on user interest model, job recommendation can be extracted for users. The algorithm is implemented as a parallelized recommendation system on Spark. A set of experiments have been done and analysed. The proposed algorithm achieves significant improvement in accuracy, recall rate and coverage, compared with recommendation algorithms such as UserCF and ItemCF.

  3. What sparks interest in science? A naturalistic inquiry

    Science.gov (United States)

    Jackson, Julie Kay Cropper

    This study examined how career scientists became interested in science. Eight practicing scientists were asked a focus question, "What sparked your interest in science?" Their responses recorded during personal interviews and reported in correspondence frame this qualitative study. Analysis of the data revealed a variety of influences. The influences were coded, arranged into lists, and grouped by theme. A total of 18 themes emerged from the data. Five of the emerging themes were common across all of the participants. They were the influence of a family member, the influence of a teacher, being naturally curious, being interested in science, and reading books, magazines, and/or encyclopedias. Five themes were common among 5 to 7 participants. These themes included visiting museums, having broad exposure, enjoyment of mathematics, enjoying being outside, and freedom to play and explore. Eight themes were common among 2 to 4 of the participants. They were financial incentive, influence of religion, participation in science fairs, influence of the manned space program, having a scientist in the family, having the opportunity to teach others, not seeing self as a scientist, and first generation college graduate. The emerging themes were compared and contrasted with historical and contemporary literature. Vocational psychology's leading career choice and development literature was also aligned with the emerging themes. Data from this study supports tenets of Trait and Factor Theory, Developmental Theory, and Social Learning Theory. Reported data also supports the proposed movement toward a unified theory of career choice and development. A combination of personality traits, developmental stages, self-efficacy, and learning experiences influenced the vocational decisions of the scientists who participated in this study. The study concludes with suggestions for sparking and sustaining interest in science that people responsible for preparing future scientists may find

  4. Mechanochemical synthesis and spark plasma sintering of the cerium silicides

    Energy Technology Data Exchange (ETDEWEB)

    Alanko, Gordon A.; Jaques, Brian; Bateman, Allyssa [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Butt, Darryl P., E-mail: darrylbutt@boisestate.edu [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States)

    2014-12-15

    Highlights: • Ce{sub 5}Si{sub 3}, Ce{sub 3}Si{sub 2}, CeSi, CeSi{sub 2−x} and CeSi{sub 2} were mechanochemically synthesized. • Temperature and pressure were monitored to investigate reaction progress. • All syntheses proceeded through a MSR event followed by rapid solid-state diffusion. • Milling time before MSR correlates well with effective heat of formation. • Some synthesized material was densified by spark plasma sintering. - Abstract: The cerium silicides, Ce{sub 5}Si{sub 3}, Ce{sub 3}Si{sub 2}, CeSi, CeSi{sub 2−y}, and CeSi{sub 2−x}, have been prepared from the elements by mechanochemical processing in a planetary ball mill. Preparation of the cerium silicide Ce{sub 5}Si{sub 4} was unsuccessfully attempted and potential reasons for this are discussed. Temperature and pressure of the milling vial were monitored in situ to gain insight into the mechanochemical reaction kinetics, which include a mechanically-induced self-propagating reaction (MSR). Some prepared powders were consolidated by spark plasma sintering to high density. Starting materials, as-milled powders, and consolidated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results obtained help elucidate key questions in mechanochemical processing of intermetallics, showing first phase formation similar to thin films, MSR ignition times that are composition- and milling speed-dependent, and sensitivity of stable compound formation on the impact pressure. The results demonstrate mechanochemical synthesis as a viable technique for rare earth silicides.

  5. 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.

  6. 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.

  7. Hydrostatic Hyperbaric Chamber Ventilation System

    Science.gov (United States)

    Sarguisingh, Miriam J.

    2012-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware

  8. The decay of a lambda particle in the 32 cm hydrogen bubble chamber

    CERN Multimedia

    1960-01-01

    This image from 1960 is of real particle tracks formed in CERN's first liquid hydrogen bubble chamber to be used in experiments. It was a tiny detector by today's standards at only 32 cm in diameter. Negatively charged pions with an energy of 16 GeV enter from the left. One of them interacts with a proton in the liquid hydrogen and creates sprays of new particles, including a neutral particle (a lambda) that decays to produce the "V" of two charged particle tracks at the centre. Lower-energy charged particles produced in the interactions spiral in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real particle tracks to be seen and photographed, after releasing the pressure that had kept a liquid above its normal boiling point.

  9. 44 CFR 15.12 - Photographs and other depictions.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Photographs and other... NATIONAL EMERGENCY TRAINING CENTER § 15.12 Photographs and other depictions. (a) Photographs and other depictions at Mt. Weather. We prohibit taking photographs and making notes, sketches, or diagrams of...

  10. 8 CFR 1236.5 - Fingerprints and photographs.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Fingerprints and photographs. 1236.5... ORDERED REMOVED Detention of Aliens Prior to Order of Removal § 1236.5 Fingerprints and photographs. Every... photographed. Such fingerprints and photographs shall be made available to Federal, State, and local law...

  11. 8 CFR 333.1 - Description of required photographs.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Description of required photographs. 333.1 Section 333.1 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY NATIONALITY REGULATIONS PHOTOGRAPHS § 333.1 Description of required photographs. (a) Every applicant required to furnish photographs of...

  12. Establishment of a radon test chamber

    International Nuclear Information System (INIS)

    Chen Chingjiang; Liu Chichang; Lin Yuming

    1993-01-01

    A walk-in type radon test chamber of 23 m 3 has been built for testing and calibration of radon measurement instruments. The environmental conditions of the test chamber can be varied within a wide range of values. The design objectives specification, monitoring instruments and testing results of this chamber are discussed. This test chamber is available for domestic radon researchers and its accuracy can be traced to the international standard. A routine intercomparison study will be held annually by using this chamber. Other tests like radon progeny and thoron standard may also be performed in this chamber. (1 fig.)

  13. Pencil-shaped radiation detection ionization chamber

    International Nuclear Information System (INIS)

    Suzuki, A.

    1979-01-01

    A radiation detection ionization chamber is described. It consists of an elongated cylindrical pencil-shaped tubing forming an outer wall of the chamber and a center electrode disposed along the major axis of the tubing. The length of the chamber is substantially greater than the diameter. A cable connecting portion at one end of the chamber is provided for connecting the chamber to a triaxial cable. An end support portion is connected at the other end of the chamber for supporting and tensioning the center electrode. 17 claims

  14. On the spatial errors and resolution of near tracks when parallel tracing by their images on photographs

    International Nuclear Information System (INIS)

    Ehrglis, K.Eh.

    1980-01-01

    Errors in the determination of spatial reference point (SRP) coordinates being reconstructed on the basis of photograph reference points are considered. The width of paths of probable track positions on photographs and the length of intersection zones of these paths with hampering track images are estimated. Conditions for a stable automatic tracing of closely traversing in space tracks are determined. The conclusion is made that of 5-6 SRP are accumulated the method of spatial tracing when shifting local scanning centres on photographs with a corresponding speed permits to trace automatically closely traversing tracks in the middle zone of the Merabel chamber when the angle between them is approximately 1 deg and the distance in space - 3-7 mm. It is emphasized that, when forecasting 8-10 SRP, the spatial or angle track resolution improves 1.5 times more due to the diminution of forecasting errors and corresponding narrowing of sensitivity paths. The described method will be especially effective when processing photographs taken in bubble chambers of a new generation at particle energies being tens-hundreds GeV [ru

  15. Energy convergence of shock waves and its destruction mechanism in cone-roof combustion chambers

    International Nuclear Information System (INIS)

    Xu, Han; Yao, Anren; Yao, Chunde; Gao, Jian

    2016-01-01

    Highlights: • Experiments with simulations are designed to probe into engine severe knock. • Energy convergence at central and edge region is observed in closed-limited space. • Modes with different intensities and mechanism of energy convergence are revealed. • Chamber shape and equivalence ratio can affect the energy convergence. • The destruction effects of energy convergence on pistons are recognized. - Abstract: Energy convergence is considered as an important phenomenon in internal combustion engines under severe knock, in which shock waves caused by violent combustion may aggregate the energy released by fuel burning to damage engine parts like pistons and spark plugs easily. In order to reveal such convergence mechanism and its destruction effects, a novel detonation bomb experiment combined with numerical simulations are conducted. In bomb experiments, a detonation wave is forcibly introduced into a clearance-variable cone-roof combustion chamber by a high energy spark ignition. Four pressure transducers were installed in different positions to monitor the energy convergence. Combined with the experiments, numerical simulations were conducted to reveal the convergence modes and mechanisms. Finally, destruction samples were presented to validate this research. It’s found that the energy convergence of shock waves always occurs in middle and edge region, which are vulnerable to be damaged. Three modes of energy convergence are concluded for middle region while several ways of energy convergence are concluded for edge region, which are all related with the chamber shape and may result in different levels of convergence. It’s also found that though detonation strength (knock intensity) can be changed by both equivalence ratios and initial pressures, only the equivalence ratios can change the convergence modes while the initial pressures cannot.

  16. [Significance of various implantate localizations of Sparks prostheses, experimental studies in rats].

    Science.gov (United States)

    Brieler, H S; Parwaresch, R; Thiede, A

    1976-01-01

    Our investigations show that Sparks prostheses after subcutaneous implantation are suitable for vascular grafting. At the end of the organization period the connective tissue becomes strong, and after the third and fourth weeks collagenous and elastic fibers can be seen. Ten weeks after s.c. implantation, collagenous fibers predominate. After this the Sparks prostheses can be used as a vascular graft. Intraperitoneal implantation, however, shows a histologically different picture with characteristic findings: only fat cells can be observed, a strong granulation tissue with elastic and collagenous fibers is not present. After intraperitoneal implantation Sparks prostheses are therefore unsuitable for vascular grafts.

  17. The secular and the supernatural: madness and psychiatry in the short stories of Muriel Spark.

    Science.gov (United States)

    Beveridge, A W

    2015-01-01

    Edinburgh-born Muriel Spark is one of modern Scotland's greatest writers. Examination of her work reveals that the subjects of madness and psychiatry are recurrent themes in her writing. She herself had a mental breakdown when she was a young woman and she took an interest in the world of psychiatry and psychoanalysis. In her short stories, Spark approaches the subject of madness in a variety of ways: she relates it to the supernatural; to writing fiction; and to religion. She frequently juxtaposes secular and supernatural explanations of mental disturbance. Spark adopts a sceptical and, at times, mocking view of psychiatrists and psychiatric treatment. Both psychoanalysis and pills are seen as problematic.

  18. Experimental evaluation of a spark-ignited engine using biogas as fuel

    Directory of Open Access Journals (Sweden)

    Juan Miguel Mantilla González

    2008-05-01

    Full Text Available Different CH4 and CO2 mixtures were used as fuel in this work; they were fed into a spark-ignited engine equipped with devices allowing spark advance, gas delivery and gas consumption to be measured. Engine bench-tests re-vealed changes in the main operation parameters and emissions. The results showed that increasing CO2 percen-tage in the mixture increased the spark angle, reduced maximum power and torque and reduced exhaust emissions (by 90% in some cases when DAMA resolution 1015/2005 was applied. The main components to be considered when an engine of this type operates with gas fuel were also recognised.

  19. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    OpenAIRE

    Zhaoxiang Chen; Xipeng Ren; Limei Ren; Tengchao Wang; Xiaowen Qi; Yulin Yang

    2018-01-01

    Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC ...

  20. Damping Resonant Current in a Spark-Gap Trigger Circuit to Reduce Noise

    Science.gov (United States)

    2009-06-01

    DAMPING RESONANT CURRENT IN A SPARK- GAP TRIGGER CIRCUIT TO REDUCE NOISE E. L. Ruden Air Force Research Laboratory, Directed Energy Directorate, AFRL...REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Damping Resonant Current In A Spark- Gap Trigger Circuit To Reduce Noise 5a...thereby triggering 2 after delay 0, is 1. Each of the two rail- gaps (represented by 2) is trig- gered to close after the spark- gap (1) in the

  1. 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.

  2. 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).

  3. Single wire drift chamber design

    International Nuclear Information System (INIS)

    Krider, J.

    1987-01-01

    This report summarizes the design and prototype tests of single wire drift chambers to be used in Fermilab test beam lines. The goal is to build simple, reliable detectors which require a minimum of electronics. Spatial resolution should match the 300 μm rms resolution of the 1 mm proportional chambers that they will replace. The detectors will be used in beams with particle rates up to 20 KHz. Single track efficiency should be at least 99%. The first application will be in the MT beamline, which has been designed for calibration of CDF detectors. A set of four x-y modules will be used to track and measure the momentum of beam particles

  4. MPS II drift chamber system

    International Nuclear Information System (INIS)

    Platner, E.D.

    1982-01-01

    The MPS II detectors are narrow drift space chambers designed for high position resolution in a magnetic field and in a very high particle flux environment. Central to this implementation was the development of 3 multi-channel custom IC's and one multi-channel hybrid. The system is deadtimeless and requires no corrections on an anode-to-anode basis. Operational experience and relevance to ISABELLE detectors is discussed

  5. Photographic program of a BWR for ALARA

    International Nuclear Information System (INIS)

    Dodd, A.M.; Parry, J.O.

    1984-01-01

    High radiation areas have often been photographed in commercial nuclear plants to identify radiation sources and equipment so workers having to go into the areas become familiar with them prior to entering. This helps minimize the workers' time in a high radiation area and is useful as a visual aid in training. Previous problems encountered in using this type of file included indexing, storing for long term use and reproducing photos for use in the field. At WNP-2, a program has been adopted from Aerojet of Idaho where negatives from photographs are mounted on computer aperture cards. The cards are coded to identify the equipment, physical location in the plant, reference drawings and other data. The aperture cards are reproduced using a process called Diazo. The information is put in a data file that can be sorted by any field on the card. A paper copy of the photo can be made in seconds on a machine similar to a dry silver copier, then mounted for training or maintenance purposes. The cost of duplicating the aperture cards and/or the paper copies is a fraction of that for reproducing color glossies. The computer data file provides cross-referencing to correlate the equipment with the photograph. The results are low cost, easy storage and easy access to the photograph file. Using this program, several thousand photographs can easily be stored and used

  6. 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...

  7. Dorsal skinfold chamber models in mice

    Directory of Open Access Journals (Sweden)

    Schreiter, Jeannine

    2017-07-01

    Full Text Available Background/purpose: The use of dorsal skinfold chamber models has substantially improved the understanding of micro-vascularisation in pathophysiology over the last eight decades. It allows pathophysiological studies of vascularisation over a continuous period of time. The dorsal skinfold chamber is an attractive technique for monitoring the vascularisation of autologous or allogenic transplants, wound healing, tumorigenesis and compatibility of biomaterial implants. To further reduce the animals’ discomfort while carrying the dorsal skinfold chamber, we developed a smaller chamber (the Leipzig Dorsal Skinfold Chamber and summarized the commercial available chamber models. In addition we compared our model to the common chamber. Methods: The Leipzig Dorsal Skinfold Chamber was applied to female mice with a mean weight of 22 g. Angiogenesis within the dorsal skinfold chamber was evaluated after injection of fluorescein isothiocyanate dextran with an Axio Scope microscope. The mean vessel density within the dorsal skinfold chamber was assessed over a period of 21 days at five different time points. The gained data were compared to previous results using a bigger and heavier dorsal skinfold model in mice. A PubMed and a patent search were performed and all papers related to “dorsal skinfold chamber” from 1 of January 2006 to 31 of December 2015 were evaluated regarding the dorsal skinfold chamber models and their technical improvements. The main models are described and compared to our titanium Leipzig Dorsal Skinfold Chamber model.Results: The Leipzig Dorsal Skinfold Chamber fulfils all requirements of continuous models known from previous chamber models while reducing irritation to the mice. Five different chamber models have been identified showing substantial regional diversity. The newly elaborated titanium dorsal skinfold chamber may replace the pre-existing titanium chamber model used in Germany so far, as it is smaller and lighter

  8. 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......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber-grown biofilms are addressed....

  9. Impedances in lossy elliptical vacuum chambers

    International Nuclear Information System (INIS)

    Piwinski, A.

    1994-04-01

    The wake fields of a bunched beam caused by the resistivity of the chamber walls are investigated for a vacuum chamber with elliptical cross section. The longitudinal and transverse impedances are calculated for arbitrary energies and for an arbitrary position of the beam in the chamber. (orig.)

  10. Wire chamber degradation at the Argonne ZGS

    International Nuclear Information System (INIS)

    Haberichter, W.; Spinka, H.

    1986-01-01

    Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM

  11. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  12. Sensitivity of gaseous xenon ionisation chambers (1961)

    International Nuclear Information System (INIS)

    Schuhl, C.

    1960-01-01

    It seems advantageous to fill an ionization chamber with xenon gas when this chamber is used for measuring a low intensity and high energy electron or positron beam, or monitoring a gamma beam. In the study of 5 to 50 MeV electrons, xenon allows for the ionization chamber yield, an improvement of a factor 4,5. (author) [fr

  13. Nobels Nobels laureates photographed by Peter Badge

    CERN Document Server

    2008-01-01

    A unique photographic record of all living Nobel laureates. In this handsome coffee-table book, photographer Peter Badge captures the likeness of every living Nobel laureate in a lasting black-and-white image -- more than 300 striking portraits in all. Brief biographical sketches accompanying the large-scale photographs pay homage to each laureate's singular contribution to science, literature or world peace. Bringing readers face-to-face with Nelson Mandela, Jimmy Carter, the Dalai Lama, James Watson, Gabriel García Márquez, Toni Morrison, Rita Levi-Montalcini, Linda Buck, and Paul Samuelson among many others, NOBELS offers an intimate and compelling look at well-known honorees as well as lesser-known recipients. A fascinating word/image tableau.

  14. A Relational Ecology of Photographic Practices

    Directory of Open Access Journals (Sweden)

    Jacqui Knight

    2017-11-01

    Full Text Available This paper proposes a relational history of media artifacts, which decentralizes the dominance of the photographer or filmmaker as the absolute author of the work. It adds an alternative account to understanding the creative process and the subsequent study of media forms by discussing film and photographic practices as the reciprocal affective relationship between the maker, their intentions, materials, technologies, non-human agents and the environment. By reorganizing the anthropocentrism of art historical narratives, which typically exclude corporeality and materiality as drivers of human history, we are able to discuss the complex dynamic meshwork of determinants that bring photographic artifacts into existence: the lived, animate, vital materialism at once emergent and mixing of different causalities and temporalities.

  15. Spark PRM: Using RRTs within PRMs to efficiently explore narrow passages

    KAUST Repository

    Shi, Kensen

    2014-05-01

    © 2014 IEEE. Probabilistic RoadMaps (PRMs) have been successful for many high-dimensional motion planning problems. However, they encounter difficulties when mapping narrow passages. While many PRM sampling methods have been proposed to increase the proportion of samples within narrow passages, such difficult planning areas still pose many challenges. We introduce a novel algorithm, Spark PRM, that sparks the growth of Rapidly-expanding Random Trees (RRTs) from narrow passage samples generated by a PRM. The RRT rapidly generates further narrow passage samples, ideally until the passage is fully mapped. After reaching a terminating condition, the tree stops growing and is added to the roadmap. Spark PRM is a general method that can be applied to all PRM variants. We study the benefits of Spark PRM with a variety of sampling strategies in a wide array of environments. We show significant speedups in computation time over RRT, Sampling-based Roadmap of Trees (SRT), and various PRM variants.

  16. Passenger Car Spark Ignition Data Base : Volume 3. Miscellaneous Data. Part 2.

    Science.gov (United States)

    1979-12-01

    Test data was obtained from spark ignition production and preproduction engines at the engine and vehicle level. The engines were applicable for vehicles 2000 to 3000 pounds in weight. The data obtained provided trade-offs between fuel economy, power...

  17. Passenger Car Spark Ignition Data Base : Volume 3. Miscellaneous Data. Part 1.

    Science.gov (United States)

    1979-12-01

    Test data was obtained from spark ignition production and preproduction engines at the engine and vehicle level. The engines were applicable for vehicles 2000 to 3000 pounds in weight. The data obtained provided trade-offs between fuel economy, power...

  18. Quantitative determination of minor and trace elements in rocks and soils by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Ure, A.M.; Bacon, J.R.

    1978-01-01

    Experimental details are given of the quantitative determination of minor and trace elements in rocks and soils by spark source mass spectrometry. The effects of interfering species, and corrections that can be applied, are discussed. (U.K.)

  19. Spark PRM: Using RRTs within PRMs to efficiently explore narrow passages

    KAUST Repository

    Shi, Kensen; Denny, Jory; Amato, Nancy M.

    2014-01-01

    © 2014 IEEE. Probabilistic RoadMaps (PRMs) have been successful for many high-dimensional motion planning problems. However, they encounter difficulties when mapping narrow passages. While many PRM sampling methods have been proposed to increase the proportion of samples within narrow passages, such difficult planning areas still pose many challenges. We introduce a novel algorithm, Spark PRM, that sparks the growth of Rapidly-expanding Random Trees (RRTs) from narrow passage samples generated by a PRM. The RRT rapidly generates further narrow passage samples, ideally until the passage is fully mapped. After reaching a terminating condition, the tree stops growing and is added to the roadmap. Spark PRM is a general method that can be applied to all PRM variants. We study the benefits of Spark PRM with a variety of sampling strategies in a wide array of environments. We show significant speedups in computation time over RRT, Sampling-based Roadmap of Trees (SRT), and various PRM variants.

  20. Preparation of Ni-Ti shape memory alloy by spark plasma sintering method

    Czech Academy of Sciences Publication Activity Database

    Salvetr, P.; Kubatík, Tomáš František; Novák, P.

    2016-01-01

    Roč. 16, č. 4 (2016), s. 804-808 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Ni-Ti alloy * Powder metallurgy * Reactive sintering * Spark plasma sintering Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  1. High speed streak techniques for measuring the growth of spark channels

    International Nuclear Information System (INIS)

    Suleebka, P.

    1975-01-01

    The manner of expansion of an electric spark channel is of interest in the understanding of such phenomena as lightning. The development of a camera suitable for photography of this expansion is described, with some results for hydrogen. (author)

  2. Apparatus and method for the spectrochemical analysis of liquids using the laser spark

    Science.gov (United States)

    Cremers, David A.; Radziemski, Leon J.; Loree, Thomas R.

    1990-01-01

    A method and apparatus for the qualitative and quantitative spectroscopic investigation of elements present in a liquid sample using the laser spark. A series of temporally closely spaced spark pairs is induced in the liquid sample utilizing pulsed electromagnetic radiation from a pair of lasers. The light pulses are not significantly absorbed by the sample so that the sparks occur inside of the liquid. The emitted light from the breakdown events is spectrally and temporally resolved, and the time period between the two laser pulses in each spark pair is adjusted to maximize the signal-to-noise ratio of the emitted signals. In comparison with the single pulse technique, a substantial reduction in the limits of detectability for many elements has been demonstrated. Narrowing of spectral features results in improved discrimination against interfering species.

  3. Proportional chambers and multiwire drift chambers at high rates

    International Nuclear Information System (INIS)

    Walenta, A.H.

    1977-01-01

    The high event and particle rates expected for ISABELLE intersecting storage rings raise the question whether PWC's and drift chambers, now widely in use in experiments, still can operate under such conditions. Various effects depend on the number of avalanches produced per length of wire N and the size of the avalanche Q, i.e., on the number of positive ions created in an avalanche. Therefore the important parameter for the following discussion is the product QN. The minimum Q is determined by the type and noise level of preamplifiers used. Examples are given for a typical low noise amplifier as well as for a typical integrated ''cheap'' amplifier. The rate/wire length N depends on the chamber arrangement, wire spacing, etc. In multiwire drift chambers, a single wire shows space-charge effects reducing the pulse height by 1% at a rate of N = 7 x 10 3 mm -1 sec -1 . At a rate of N approximately equal to 10 5 mm -1 sec -1 an efficiency loss of the order of 1% was noticed. The aging effect due to deposits on the anode wire can be reduced using low noise amplifiers and low gas gain to such an extent that a lifetime of about half a year at ISABELLE can be expected. The use of conventional cheap preamplifiers will result in a typical lifetime of about 30 days. Improvements are probable. The time resolution of Δt/sub r/ = 4 nsec fwhm seems adequate for event rates of 10 7 sec -1 . The memory time Δt/sub m/ greater than or equal to 100 nsec may cause serious problems for pattern recognition depending on layout and readout. The use of induced signals on cathode pads, thus reading out shorter parts of the wire, can solve the problem

  4. 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...

  5. Breakdown characteristics in DC spark experiments of copper focusing on purity and hardness

    CERN Document Server

    Yokoyama, Kazue; Higashi, Yasuo; Higo, Toshi; Matsumoto, Shuji; Santiago-Kern, Ana Rocia; Pasquino, Chiara; Calatroni, Sergio; Wuensch, Walter

    2010-01-01

    The breakdown characteristics related to the differences in purity and hardness were investigated for several types of copper using a DC spark test system. Three types of oxygen-free copper (OFC) materials, usual class 1 OFC 7-nine large-grain copper and 6-nine hot-isotropic-pressed (HIP) copper with/without diamond finish, were tested with the DC spark test system. The measurements of the beta, breakdown fields, and breakdown probability are presented and discussed in this paper.

  6. Meter of dynamics of restoring the electrical strength of spark gaps

    International Nuclear Information System (INIS)

    Kuznetsov, E.A.; Kravchenko, S.A.; Yagnov, V.A.; Shipuk, I.Ya.

    1997-01-01

    Method for diagnostics of the dynamics spark gap electric strength restoration and an electric device for its realization are described. The electric strength measurement error, conditioned by the breakdown current through electric probes or the contacts of a spark gap under investigation, is reduced to minimum due to fast switching off the probe voltage if the breakdown current exceeds some established value (1 mA). 1 ref

  7. Analyzing large data sets from XGC1 magnetic fusion simulations using apache spark

    Energy Technology Data Exchange (ETDEWEB)

    Churchill, R. Michael [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2016-11-21

    Apache Spark is explored as a tool for analyzing large data sets from the magnetic fusion simulation code XGCI. Implementation details of Apache Spark on the NERSC Edison supercomputer are discussed, including binary file reading, and parameter setup. Here, an unsupervised machine learning algorithm, k-means clustering, is applied to XGCI particle distribution function data, showing that highly turbulent spatial regions do not have common coherent structures, but rather broad, ring-like structures in velocity space.

  8. Development of Curriculum of Learning through Photograph

    Science.gov (United States)

    Suzuki, Keiko; Aoki, Naokazu; Kobayashi, Hiroyuki

    A curriculum of an integrated learning using power of photography in the junior highschool was constructed, and was experimented in the class "Seminar for Photographic Expression" of the integrated learning at a junior high school. The center of the curriculum is viewing photographs and self-expression using photography. By comparing the results of questionnaires investigation between before and after the class it is suggested that the curriculum brings about increase in self-esteem, empathy, and motivation for learning. This educational effect is really to foster ability to live self-sufficient lives. On the basis of these results curriculums which can be conducted by anyone at every junior highschool were proposed.

  9. Organisation of a laboratory of photographic dosimetry

    International Nuclear Information System (INIS)

    Soudain, Georges

    1961-01-01

    After a recall of the main properties of photographic dosimetry, the author describes the principle of this method, and comments the issue of chromatic sensitivity of photographic emulsions. He discusses the calibration process for gamma radiation, X rays, and thermal neutrons. He describes how fast neutron dosimetry is performed. In the next part, he describes the organisation of the photometry laboratory which has to prepare and distribute dosimeters, to collect and exploit them, and to prepare a publication of results. These different missions and tasks are described

  10. Salvaging and Conserving Water Damaged Photographic Materials

    Science.gov (United States)

    Suzuki, Ryuji

    Degradation of water damaged photographic materials is discussed; the most vulnerable elements are gelatin layers and silver image. A simple and inexpensive chemical treatment is proposed, consisting of a bath containing a gelatin-protecting biocide and a silver image protecting agent. These ingredients were selected among those used in manufacturing of silver halide photographic emulsions or processing chemicals. Experiments confirmed that this treatment significantly reduced oxidative attacks to silver image and bacterial degradation of gelatin layers. The treated material was also stable under intense light fading test. Method of hardening gelatin to suppress swelling is also discussed.

  11. Modeling and optimization of the multichannel spark discharge

    International Nuclear Information System (INIS)

    Zhang Zhi-Bo; Wu Yun; Jia Min; Song Hui-Min; Li Ying-Hong; Sun Zheng-Zhong

    2017-01-01

    This paper reports a novel analytic model of this multichannel spark discharge, considering the delay time in the breakdown process, the electric transforming of the discharge channel from a capacitor to a resistor induced by the air breakdown, and the varying plasma resistance in the discharge process. The good agreement between the experimental and the simulated results validated the accuracy of this model. Based on this model, the influence of the circuit parameters on the maximum discharge channel number (MDCN) is investigated. Both the input voltage amplitude and the breakdown voltage threshold of each discharge channel play a critical role. With the increase of the input voltage and the decrease of the breakdown voltage, the MCDN increases almost linearly. With the increase of the discharge capacitance, the MDCN first rises and then remains almost constant. With the increase of the circuit inductance, the MDCN increases slowly but decreases quickly when the inductance increases over a certain value. There is an optimal value of the capacitor connected to the discharge channel corresponding to the MDCN. Finally, based on these results, to shorten the discharge time, a modified multichannel discharge circuit is developed and validated by the experiment. With only 6-kV input voltage, 31-channels discharge is achieved. The breakdown voltage of each electrode gap is larger than 3 kV. The modified discharge circuit is certain to be widely used in the PSJA flow control field. (paper)

  12. Collision experiment on highly ionized ions using vacuum spark source

    International Nuclear Information System (INIS)

    Takagi, S.; Ohtani, S.; Kadota, K.; Fujita, J.

    1982-03-01

    Cross sections for one-electron capture by Fe 6 + in H 2 are measured below 10 keV by using a vacuum spark ion source. It is found that the cross sections show little dependence on the collision energy and this value is about 6 x 10 - 15 cm 2 . This ion source, which has no electrode for ion extraction, can produce ions from several hundreds eV to several tens of keV and the maximum charge state of 16 in Fe at 125J discharge energy. With ion selection system of 2.7 m time-of-flight and an electrostatic analyzer of 1% resolving power, 10 2 - 10 3 ions/pulse are obtained. Because of poor reproducibility of ion beam, charge-transferred ions and unreacted ions are measured simultaneously with a microchannel plate which has two anodes behind. By utilizing the feature of pulsed ion beam and this ion selection system, it is possible to obtain cross sections for various charge states of ions simultaneously. (author)

  13. A prediction study of a spark ignition supercharged hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Al-Baghdadi, M.A.R.S.; Al-Janabi, H.A.K.S. [University of Babylon (Iraq). Dept. of Mechanical Engineering

    2003-12-01

    Hydrogen is found to be a suitable alternative fuel for spark ignition engines with certain drawbacks, such as high NO{sub x} emission and small power output. However, supercharging may solve such problems. In this study, the effects of equivalence ratio, compression ratio and inlet pressure on the performance and NO{sub x} emission of a four stroke supercharged hydrogen engine have been analyzed using a specially developed computer program. The results are verified and compared with experimental data obtained from tests on a Ricardo E6/US engine. A chart specifying the safe operation zone of the hydrogen engine has been produced. The safe operation zone means no pre-ignition, acceptable NO{sub x} emission, high engine efficiency and lower specific fuel consumption in comparison with the gasoline engine. The study also shows that supercharging is a more effective method to increase the output of a hydrogen engine rather than increasing the compression ratio of the engine at the knock limited equivalence ratio. (author)

  14. Spark plasma sintering of titanium aluminide intermetallics and its composites

    Science.gov (United States)

    Aldoshan, Abdelhakim Ahmed

    Titanium aluminide intermetallics are a distinct class of engineering materials having unique properties over conventional titanium alloys. gamma-TiAl compound possesses competitive physical and mechanical properties at elevated temperature applications compared to Ni-based superalloys. gamma-TiAl composite materials exhibit high melting point, low density, high strength and excellent corrosion resistance. Spark plasma sintering (SPS) is one of the powder metallurgy techniques where powder mixture undergoes simultaneous application of uniaxial pressure and pulsed direct current. Unlike other sintering techniques such as hot iso-static pressing and hot pressing, SPS compacts the materials in shorter time (< 10 min) with a lower temperature and leads to highly dense products. Reactive synthesis of titanium aluminide intermetallics is carried out using SPS. Reactive sintering takes place between liquid aluminum and solid titanium. In this work, reactive sintering through SPS was used to fabricate fully densified gamma-TiAl and titanium aluminide composites starting from elemental powders at different sintering temperatures. It was observed that sintering temperature played significant role in the densification of titanium aluminide composites. gamma-TiAl was the predominate phase at different temperatures. The effect of increasing sintering temperature on microhardness, microstructure, yield strength and wear behavior of titanium aluminide was studied. Addition of graphene nanoplatelets to titanium aluminide matrix resulted in change in microhardness. In Ti-Al-graphene composites, a noticeable decrease in coefficient of friction was observed due to the influence of self-lubrication caused by graphene.

  15. Social Interactions Sparked by Pictorial Warnings on Cigarette Packs

    Directory of Open Access Journals (Sweden)

    Marissa G. Hall

    2015-10-01

    Full Text Available The Message Impact Framework suggests that social interactions may offer smokers the opportunity to process pictorial warnings on cigarette packs more deeply. We aimed to describe adult smokers’ social interactions about pictorial cigarette pack warnings in two longitudinal pilot studies. In Pilot Study 1, 30 smokers used cigarette packs with one of nine pictorial warnings for two weeks. In Pilot Study 2, 46 smokers used cigarette packs with one of five pictorial warnings for four weeks. Nearly all smokers (97%/96% in Pilot Study 1/2 talked about the warnings with other people, with the most common people being friends (67%/87% and spouses/significant others (34%/42%. Pilot Study 2 found that 26% of smokers talked about the warnings with strangers. Discussions about the health effects of smoking and quitting smoking were more frequent during the first week of exposure to pictorial warnings than in the week prior to beginning the study (both p < 0.05. Pictorial warnings sparked social interactions about the warnings, the health effects of smoking, and quitting smoking, indicating that pictorial warnings may act as a social intervention reaching beyond the individual. Future research should examine social interactions as a potential mediator of the impact of pictorial warnings on smoking behavior.

  16. Consolidation of copper and aluminium powders by spark plasma sintering

    Science.gov (United States)

    Saiprasad, M.; Atchayakumar, R.; Thiruppathi, K.; Raghuraman, S.

    2016-09-01

    Processing in the powder metallurgy route has emerged as an economical process for the production of near net shaped components with a wide range of desired mechanical properties suitable for various applications of industrial needs. This research work was conducted with an objective of studying the improvisation of density and hardness of Copper-Aluminium alloy prepared by spark plasma sintering. Cu-Al alloy with a composition of 95% copper and 5% aluminium was prepared by SPS process. SPS is a low voltage, DC pulse current activated, pressure-assisted sintering, which enables sintering at lower temperatures and shorter durations. The combination offered by Cu-Al alloy of high strength and high corrosion resistance results their applications under a wide variety of conditions. The density and hardness of the prepared sample were measured by conducting appropriate tests. Apparently, the values of hardness and density of the specimen prepared by SPS seemed to be better than that of conventional sintering. The experimental procedure, testing methodologies and analysis are presented.

  17. PREFACE: Workshop Photograph and Program

    Science.gov (United States)

    2011-07-01

    Workshop photograph Workshop Program Sunday 28 March 201019:00-21:00 Reception at Okura Frontier Hotel Tsukuba(Buffet style dinner with drink) Monday 29 March 2010Introduction (Chair: André Rubbia (ETH Zurich))09:00 Welcome address (05') Atsuto Suzuki (KEK)09:05 Message from CERN on neutrino physics (10') Sergio Bertolucci (CERN)09:15 Message from FNAL on neutrino physics (10') Young Kee Kim (FNAL)09:25 Message from KEK on neutrino physics (10') Koichiro Nishikawa (KEK)09:35 Introductory remark on GLA2010 (10') Takuya Hasegawa (KEK) Special session (Chair: Koichiro Nishikawa (KEK))09:45 The ICARUS Liquid Argon TPC (45') Carlo Rubbia (CERN)10:30-11:00 Coffee break Main goals of Giant Liquid Argon Charge Imaging Experiments I (Chair: Takashi Kobayashi (KEK))11:00 Results from massive underground detectors (non accelerator) (30') Takaaki Kajita (ICRR, U. of Tokyo)11:30 Present long baseline neutrino experiments (30') Chang Kee Jung (SUNY Stony Brook)12:00-12:10 Workshop picture12:10-14:00 Lunch break Main goals of Giant Liquid Argon Charge Imaging Experiments II (Chair: Takashi Kobayashi (KEK))14:00 Physics goals of the next generation massive underground experiments (30') David Wark (Imperial College London)14:30 Near detectors for long baseline neutrino experiments (20') Tsuyoshi Nakaya (Kyoto U.) Lessons on Liquid Argon Charge Imaging technology from ongoing developments (Chair: Chang Kee Jung (SUNY Stony Brook))14:50 WARP (30') Claudio Montanari (U. of Pavia)15:20 ArDM (30') Alberto Marchionni (ETH Zurich)15:50 From ArgoNeuT to MicroBooNE (30') Bonnie Fleming (Yale U.)16:20 250L (30') Takasumi Maruyama (KEK)16:50 The DEAP/CLEAN project (20') Mark Boulay (Queen's U.)17:10-17:40 Coffee break Lessons from Xe based Liquids Imaging detectors (Chair: Flavio Cavanna (U. of L'Aquilla))17:30 MEG (20') Satoshi Mihara (KEK)17:50 The XENON project (20') Elena Aprile (Columbia U.)18:10 XMASS (20') Hiroyuki Sekiya (ICRR, U. of Tokyo) Studies on physics performance (Chair

  18. A new spark detection system for the electrostatic septa of the SPS North (experimental) Area

    CERN Document Server

    Barlow, R A; Borburgh, J; Carlier, E; Chanavat, C; Fowler, T; Pinget, B

    2014-01-01

    Electrostatic septa (ZS) are used in the extraction of the particle beams from the CERN SPS to the North Area experimental zone. These septa employ high electric fields, generated from a 300 kV power supply, and are particularly prone to internal sparking around the cathode structure. This sparking degrades the electric field quality, consequently affecting the extracted beam, vacuum and equipment performance. To mitigate these effects, a Spark Detection System (SDS) has been realised, which is based on an industrial SIEMENS S7-400 programmable logic controller and deported Boolean processor modules interfaced through a PROFINET fieldbus. The SDS interlock logic uses a moving average spark rate count to determine if the ZS performance is acceptable. Below a certain spark rate it is probable that the ZS septa tank vacuum can recover, thus avoiding transition into a state where rapid degradation would occur. Above this level an interlock is raised and the high voltage is switched off. Additionally, all spark si...

  19. Ca2+ sparks act as potent regulators of excitation-contraction coupling in airway smooth muscle.

    Science.gov (United States)

    Zhuge, Ronghua; Bao, Rongfeng; Fogarty, Kevin E; Lifshitz, Lawrence M

    2010-01-15

    Ca2+ sparks are short lived and localized Ca2+ transients resulting from the opening of ryanodine receptors in sarcoplasmic reticulum. These events relax certain types of smooth muscle by activating big conductance Ca2+-activated K+ channels to produce spontaneous transient outward currents (STOCs) and the resultant closure of voltage-dependent Ca2+ channels. But in many smooth muscles from a variety of organs, Ca2+ sparks can additionally activate Ca2+-activated Cl(-) channels to generate spontaneous transient inward current (STICs). To date, the physiological roles of Ca2+ sparks in this latter group of smooth muscle remain elusive. Here, we show that in airway smooth muscle, Ca2+ sparks under physiological conditions, activating STOCs and STICs, induce biphasic membrane potential transients (BiMPTs), leading to membrane potential oscillations. Paradoxically, BiMPTs stabilize the membrane potential by clamping it within a negative range and prevent the generation of action potentials. Moreover, blocking either Ca2+ sparks or hyperpolarization components of BiMPTs activates voltage-dependent Ca2+ channels, resulting in an increase in global [Ca2+](i) and cell contraction. Therefore, Ca2+ sparks in smooth muscle presenting both STICs and STOCs act as a stabilizer of membrane potential, and altering the balance can profoundly alter the status of excitability and contractility. These results reveal a novel mechanism underlying the control of excitability and contractility in smooth muscle.

  20. 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...

  1. Proceedings of workshop on streamer chamber

    International Nuclear Information System (INIS)

    Itoh, Hidihiko; Takahashi, Kaoru; Hirose, Tachishige; Masaike, Akira

    1978-08-01

    For high accuracy observation of multiple-body reactions, a vertex detector of high efficiency is essential. A bubble chamber, though excellent for tracks detection, is problematic in statistics accuracy. The vertex detector with a wire chamber, while better in this respect, difficult in multiple-particle detection etc. The workshop has had several meetings on a streamer chamber as a detector combining features of both bubble chamber and counter, with emphasis on tracks observation in avalanche mode and recordings not using films. Contents are on streamer chamber gas, analytical photography, data processing, simulation program, etc. (Mori, K.)

  2. Optical sensor system for time-resolved quantification of methane densities in CH4-fueled spark ignition engines.

    Science.gov (United States)

    Golibrzuch, Kai; Digulla, Finn-Erik; Bauke, Stephan; Wackerbarth, Hainer; Thiele, Olaf; Berg, Thomas

    2017-08-01

    We present the development and the first application of an optical sensor system that allows single-cycle determination of methane (CH 4 ) concentration inside internal combustion (IC) engines. We use non-dispersive infrared absorption spectroscopy to detect the CH 4 density with a time resolution up to 33 μs at acquisition rates of 30 kHz. The measurement scheme takes advantage of the strong temperature dependence of the absorption band applying two detection channels for CH 4 that detect different spectral regions of the ν 3 anti-symmetric C-H-stretch absorption. The strategy allows the simultaneous determination of fuel concentration as well as gas temperature. We show the proof-of-concept by validation of the measurement strategy in static pressure cell experiments as well as its application to a methane-fueled IC engine using a modified spark plug probe. Our results clearly demonstrate that it is crucial to determine the CH 4 temperature in the probe volume. Due to thermal influences of the sensor probe, the temperature needed to calculate the desired quantities (fuel density, fuel concentration) significantly differs from the gas phase temperature in the rest of the combustion chamber and estimations from standard thermodynamic models, e.g., polytropic compression, will fail.

  3. An Experimental and Simulation Study of Early Flame Development in a Homogeneous-charge Spark-Ignition Engine

    Directory of Open Access Journals (Sweden)

    Shekhawat Y.

    2017-09-01

    Full Text Available An integrated experimental and Large-Eddy Simulation (LES study is presented for homogeneous premixed combustion in a spark-ignition engine. The engine is a single-cylinder two-valve optical research engine with transparent liner and piston: the Transparent Combustion Chamber (TCC engine. This is a relatively simple, open engine configuration that can be used for LES model development and validation by other research groups. Pressure-based combustion analysis, optical diagnostics and LES have been combined to generate new physical insight into the early stages of combustion. The emphasis has been on developing strategies for making quantitative comparisons between high-speed/high-resolution optical diagnostics and LES using common metrics for both the experiments and the simulations, and focusing on the important early flame development period. Results from two different LES turbulent combustion models are presented, using the same numerical methods and computational mesh. Both models yield Cycle-to-Cycle Variations (CCV in combustion that are higher than what is observed in the experiments. The results reveal strengths and limitations of the experimental diagnostics and the LES models, and suggest directions for future diagnostic and simulation efforts. In particular, it has been observed that flame development between the times corresponding to the laminar-to-turbulent transition and 1% mass-burned fraction are especially important in establishing the subsequent combustion event for each cycle. This suggests a range of temporal and spatial scales over which future experimental and simulation efforts should focus.

  4. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  5. On the reverse. Some notes on photographic images from the Warburg Institute Photographic Collection

    Directory of Open Access Journals (Sweden)

    Katia Mazzucco

    2012-10-01

    Full Text Available How can the visual and textual data about an image – the image of a work of art – on recto and verso of a picture be interpreted? An analogical-art-documentary photograph represents a palimpsest to be considered layer by layer. The examples discussed in this article, which refer to both Aby Warburg himself and the first nucleus of the Warburg Institute Photographic Collection, contribute to effectively outline elements of the debate around the question of the photographic reproduction of the work of art as well as of the position of photography in relation to the perception of the work of art.

  6. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1995-01-01

    Chamber transport is an important area of study for heavy ion fusion. Final focus and chamber-transport are high leverage areas providing opportunities to significantly decrease the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (approx-lt 0.003 torr), ballistic or nearly-ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (approx-gt.1 torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber then transporting it at small radius (∼ 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity

  7. Chamber propagation physics for heavy ion fusion

    International Nuclear Information System (INIS)

    Callahan, D.A.

    1996-01-01

    Chamber transport is a key area of study for heavy ion fusion. Final focus and chamber transport are high leverage areas providing opportunities to decrease significantly the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime (below about 0.003 Torr), ballistic or nearly ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime (above about 0.1 Torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber and then transporting it at small radius (about 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity. (orig.)

  8. Loss of ions in cavity ionization chambers

    International Nuclear Information System (INIS)

    Takata, N.; Tran, N.T.; Kim, E.; Marsoem, P.; Kurosawa, T.; Koyama, Y.

    2005-01-01

    Ion losses due to initial recombination, volume recombination, and back diffusion were each determined by measurements and calculations for different size cylindrical ionization chambers and spherical ionization chambers. By measuring signal currents from these ionization chambers irradiated with 60 Co gamma rays, two groups of ion losses were obtained. (Group 1) Ion loss due to initial recombination and diffusion, which changes proportionally to the inverse of the voltage applied to the ionization chambers; (and group 2) ion loss due to volume recombination, which changes proportionally to the inverse of the square of the applied voltage. The diffusion loss was obtained separately by computing electric field distributions in the ionization chambers. It was found that diffusion loss is larger than initial recombination loss for the cylindrical ionization chambers and vise versa for the spherical ionization chambers

  9. TRU waste characterization chamber gloveboxes

    International Nuclear Information System (INIS)

    Duncan, D. S.

    1998-01-01

    Argonne National Laboratory-West (ANL-W) is participating in the Department of Energy's (DOE) National Transuranic Waste Program in support of the Waste Isolation Pilot Plant (WIPP). The Laboratory's support currently consists of intrusive characterization of a selected population of drums containing transuranic waste. This characterization is performed in a complex of alpha containment gloveboxes termed the Waste Characterization Gloveboxes. Made up of the Waste Characterization Chamber, Sample Preparation Glovebox, and the Equipment Repair Glovebox, they were designed as a small production characterization facility for support of the Idaho National Engineering and Environmental Laboratory (INEEL). This paper presents salient features of these gloveboxes

  10. Experimental work on drift chambers

    International Nuclear Information System (INIS)

    Alcaraz, J.; Duran, I.; Gonzalez, E.; Martinez-Laso, L.; Olmos, P.

    1989-01-01

    An experimental work made on drift chambers is described in two chapters. In the firt chapter we present the description of the experimental installation used, as well as some details on the data adquisition systems and the characteristics on three ways used for calibration proposes (cosmic muons, β radiation and test beam using SPS at CERN facilities). The second chapter describes the defferent prototypes studied. The experimental set up and the analysis are given. Some results are discussed. The magnetic field effect is also studied. (Author)

  11. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    1979-05-01

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  12. Gnathostomiasis of the anterior chamber

    Directory of Open Access Journals (Sweden)

    Barua P

    2007-01-01

    Full Text Available Ocular involvement with Gnathostoma spinigerum occurs years after the initial infection that is acquired by ingestion of poorly cooked, pickled seafood or water contaminated with third stage larvae. Here we report a case of gnathostomiasis of the left eye of a 32-year-old lady hailing from Meghalaya, India. Her vision had deteriorated to hand movement. Slit lamp examination revealed a live, actively motile worm in the anterior chamber, which was extracted by supra temporal limbal incision and visual acuity was restored.

  13. An innovative system for supplying air and fuel mixture to a combustion chamber of an engine

    Science.gov (United States)

    Saikumar, G. R. Bharath

    2018-04-01

    Conventional carburetors are being used since decades to ensure that the desired ratio of air and fuel enters the combustion chamber for combustion for the purpose of generating power in an Spark Ignition(SI) internal combustion engine. However to increase the efficiency, the carburetor system is gradually being replaced by fuel injection systems. Fuel injection systems use injectors to supply pressurized fuel into the combustion chamber. Owing to the high initial and maintenance cost, carburetors are still ruling in the low cost vehicle domain. An innovative concept is conceived, which is an alternative method to the carburetor system to supply the air and fuel mixture to a combustion chamber of an engine. This system comprises of an inner hollow cylinder with minute holes drilled along its length with an outer cylinder capable of sliding along its length or its longitudinal axis. This system is placed in the venturi instead of the conventional carburetor system. Fuel enters from the bottom inlet of the inner cylinder and flows out through the holes provided along its length. The fuel flow from the inner cylinder is dependent on the size and the number of holes exposed at that instance by the sliding outer cylinder which in turn is connected to the throttle or accelerator.

  14. Cryptography Would Reveal Alterations In Photographs

    Science.gov (United States)

    Friedman, Gary L.

    1995-01-01

    Public-key decryption method proposed to guarantee authenticity of photographic images represented in form of digital files. In method, digital camera generates original data from image in standard public format; also produces coded signature to verify standard-format image data. Scheme also helps protect against other forms of lying, such as attaching false captions.

  15. The Social Effects of War Photographs

    Directory of Open Access Journals (Sweden)

    Gökhan DEMİREL

    2017-07-01

    Full Text Available In today’s world, knowledge is increasingly impacted via visual representation. The messages sent through various sources, such as newspaper, television and the internet, lead people to form opinions about various topics. In this context, photography is one of the most powerful source of information. Moreover, the visual power and the ability to show nonverbal communication makes it a perfect tool for propaganda. These days, photographs showing war themes are used more often than the past. It can be said that war photographs serve as a tool for showing the world the realities of war to those, even to those who turn their back to massacres. After all, a dead body creates a shocking effect in the seer. In this study, the context of the photographs of the war, examined in sample of photograph of Aylan Kurdi, which became the “icon” of immigration due to Syrian civil war and war it relates to and it is studied to understand how it is assessed and understood considering the environment and conditions on the date the photo was taken, existing values, beliefs and things happened in the world in that time, from a critical point of view.

  16. SciSpark's SRDD : A Scientific Resilient Distributed Dataset for Multidimensional Data

    Science.gov (United States)

    Palamuttam, R. S.; Wilson, B. D.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; McGibbney, L. J.; Ramirez, P.

    2015-12-01

    Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We have developed SciSpark, a robust Big Data framework, that extends ApacheTM Spark for scaling scientific computations. Apache Spark improves the map-reduce implementation in ApacheTM Hadoop for parallel computing on a cluster, by emphasizing in-memory computation, "spilling" to disk only as needed, and relying on lazy evaluation. Central to Spark is the Resilient Distributed Dataset (RDD), an in-memory distributed data structure that extends the functional paradigm provided by the Scala programming language. However, RDDs are ideal for tabular or unstructured data, and not for highly dimensional data. The SciSpark project introduces the Scientific Resilient Distributed Dataset (sRDD), a distributed-computing array structure which supports iterative scientific algorithms for multidimensional data. SciSpark processes data stored in NetCDF and HDF files by partitioning them across time or space and distributing the partitions among a cluster of compute nodes. We show usability and extensibility of SciSpark by implementing distributed algorithms for geospatial operations on large collections of multi-dimensional grids. In particular we address the problem of scaling an automated method for finding Mesoscale Convective Complexes. SciSpark provides a tensor interface to support the pluggability of different matrix libraries. We evaluate performance of the various matrix libraries in distributed pipelines, such as Nd4jTM and BreezeTM. We detail the architecture and design of SciSpark, our efforts to integrate climate science algorithms, parallel ingest and partitioning (sharding) of A-Train satellite observations from model grids. These

  17. Physicist makes muon chamber sing

    CERN Multimedia

    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...

  18. Lanthana-bearing nanostructured ferritic steels via spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Pasebani, Somayeh [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Charit, Indrajit, E-mail: icharit@uidaho.edu [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Wu, Yaqiao; Burns, Jatuporn; Allahar, Kerry N.; Butt, Darryl P. [Department of Materials Science and Engineering, Boise State University, Boise, ID 83725 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Cole, James I. [Idaho National Laboratory, Idaho Falls, ID 83401 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Alsagabi, Sultan F. [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States)

    2016-03-15

    A lanthana-containing nanostructured ferritic steel (NFS) was processed via mechanical alloying (MA) of Fe-14Cr-1Ti-0.3Mo-0.5La{sub 2}O{sub 3} (wt.%) and consolidated via spark plasma sintering (SPS). In order to study the consolidation behavior via SPS, sintering temperature and dwell time were correlated with microstructure, density, microhardness and shear yield strength of the sintered specimens. A bimodal grain size distribution including both micron-sized and nano-sized grains was observed in the microstructure of specimens sintered at 850, 950 and1050 °C for 45 min. Significant densification occurred at temperatures greater than 950 °C with a relative density higher than 98%. A variety of nanoparticles, some enriched in Fe and Cr oxides and copious nanoparticles smaller than 10 nm with faceted morphology and enriched in La and Ti oxides were observed. After SPS at 950 °C, the number density of Cr–Ti–La–O-enriched nanoclusters with an average radius of 1.5 nm was estimated to be 1.2 × 10{sup 24} m{sup −3}. The La + Ti:O ratio was close to 1 after SPS at 950 and 1050 °C; however, the number density of nanoclusters decreased at 1050 °C. With SPS above 950 °C, the density improved but the microhardness and shear yield strength decreased due to partial coarsening of the grains and nanoparticles.

  19. Ferritic oxide dispersion strengthened alloys by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Allahar, Kerry N., E-mail: KerryAllahar@boisestate.edu [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Burns, Jatuporn [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Jaques, Brian [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Wu, Y.Q. [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States); Charit, Indrajit [Department of Chemical and Materials Engineering, University of Idaho, McClure Hall Room 405D, Moscow, ID 83844 (United States); Cole, James [Idaho National Laboratory, Idaho Falls, ID 83401 (United States); Butt, Darryl P. [Materials and Science Engineering Department, Boise State University, 1910 University Blvd., Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd., Idaho Falls, ID 83401 (United States)

    2013-11-15

    Spark plasma sintering (SPS) was used to consolidate a Fe–16Cr–3Al (wt.%) powder that was mechanically alloyed with Y{sub 2}O{sub 3} and Ti powders to produce 0.5 Y{sub 2}O{sub 3} and 0.5 Y{sub 2}O{sub 3}–1Ti powders. The effects of mechanical alloying and sintering conditions on the microstructure, relative density and hardness of the sintered oxide dispersion strengthened (ODS) alloys are presented. Scanning electron microscopy indicated a mixed fine-grain and coarse-grain microstructure that was attributed to recrystallization and grain growth during sintering. Analysis of the transmission electron microscopy (TEM) and atom probe tomography (APT) data identified Y–O and Y–O–Ti nanoclusters. Elemental ratios of these nanoclusters were consistent with that observed in hot-extruded ODS alloys. The influence of Ti was to refine the grains as well as the nanoclusters with there being greater number density and smaller sizes of the Y–O–Ti nanoclusters as compared to the Y–O nanoclusters. This resulted in the Ti-containing samples being harder than the Ti-free alloys. The hardness of the alloys with the Y–O–Ti nanoclusters was insensitive to sintering time while smaller hardness values were associated with longer sintering times for the alloys with the Y–O nanoclusters. Pressures greater than 80 MPa are recommended for improved densification as higher sintering temperatures and longer sintering times at 80 MPa did not improve the relative density beyond 97.5%.

  20. Diesel engines vs. spark ignition gasoline engines -- Which is ``greener``?

    Energy Technology Data Exchange (ETDEWEB)

    Fairbanks, J.W. [Dept. of Energy, Washington, DC (United States)

    1997-12-31

    Criteria emissions, i.e., NO{sub x}, PM, CO, CO{sub 2}, and H{sub 2}, from recently manufactured automobiles, compared on the basis of what actually comes out of the engines, the diesel engine is greener than spark ignition gasoline engines and this advantage for the diesel engine increases with time. SI gasoline engines tend to get out of tune more than diesel engines and 3-way catalytic converters and oxygen sensors degrade with use. Highway measurements of NO{sub 2}, H{sub 2}, and CO revealed that for each model year, 10% of the vehicles produce 50% of the emissions and older model years emit more than recent model year vehicles. Since 1974, cars with SI gasoline engines have uncontrolled emission until the 3-way catalytic converter reaches operating temperature, which occurs after roughly 7 miles of driving. Honda reports a system to be introduced in 1998 that will alleviate this cold start problem by storing the emissions then sending them through the catalytic converter after it reaches operating temperature. Acceleration enrichment, wherein considerable excess fuel is introduced to keep temperatures down of SI gasoline engine in-cylinder components and catalytic converters so these parts meet warranty, results in 2,500 times more CO and 40 times more H{sub 2} being emitted. One cannot kill oneself, accidentally or otherwise, with CO from a diesel engine vehicle in a confined space. There are 2,850 deaths per year attributable to CO from SI gasoline engine cars. Diesel fuel has advantages compared with gasoline. Refinery emissions are lower as catalytic cracking isn`t necessary. The low volatility of diesel fuel results in a much lower probability of fires. Emissions could be improved by further reducing sulfur and aromatics and/or fuel additives. Reformulated fuel has become the term covering reducing the fuels contribution to emissions. Further PM reduction should be anticipated with reformulated diesel and gasoline fuels.

  1. Photographic and drafting techniques simplify method of producing engineering drawings

    Science.gov (United States)

    Provisor, H.

    1968-01-01

    Combination of photographic and drafting techniques has been developed to simplify the preparation of three dimensional and dimetric engineering drawings. Conventional photographs can be converted to line drawings by making copy negatives on high contrast film.

  2. An interactive program for digitization of seabed photographs

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.; Sharma, R.

    A program for dignitization of seabed photographs to compute coverage and abundance of polymetallic nodules is developed. Since the objects in the seabed photograph are partially covered by thin sediment layer, the automatic scanning devices may...

  3. Time perception of action photographs is more precise than that of still photographs.

    Science.gov (United States)

    Moscatelli, Alessandro; Polito, Laura; Lacquaniti, Francesco

    2011-04-01

    A photograph of an action contains implicit information about the depicted motion. Previous studies using either psychophysics or neuroimaging suggested that the neural processing of implied-motion images shares some features of real-motion processing. According to the hypothesis that the target depicted in photographs with implied motion is mentally represented as continuing in motion, such kind of photographs should be processed by the brain similarly to the individual frames of a running movie. In order to decode the functional significance of a movie, we must be able to estimate the duration of each frame and the time interval between successive frames as precisely as possible. Therefore, under naturalistic conditions, one would expect that the precision of time duration estimates is higher for action pictures than for still pictures. To test this prediction, we asked human observers to compare the variable duration of test photographs with the reference duration of their scrambled version. We found that, as expected, the duration of photographs with implied motion was discriminated better than the duration of photographs without implied motion. We also found that the average reaction time for the discrimination of photographs with implied motion was longer than that for photographs without implied motion, suggesting that the processing of implied motion involves longer and/or slower neural routes to compute time duration. This longer processing may depend on the engagement of two visual systems in parallel, one for processing form and the other one for processing implied motion. The perceptual decision about time duration would occur after the convergence of signals from these two pathways.

  4. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    International Nuclear Information System (INIS)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O

    2010-01-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N 2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10 15 cm -3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10 11 cm -3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10 8 cm -3 .

  5. Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-12-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

  6. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    Energy Technology Data Exchange (ETDEWEB)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O [Laboratoire EM2C, CNRS UPR288, Ecole Centrale Paris, 92295 Chatenay-Malabry (France)

    2010-12-15

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N{sub 2} (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10{sup 15} cm{sup -3} towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10{sup 11} cm{sup -3} produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10{sup 8} cm{sup -3}.

  7. DNS of spark ignition and edge flame propagation in turbulent droplet-laden mixing layers

    Energy Technology Data Exchange (ETDEWEB)

    Neophytou, A.; Mastorakos, E.; Cant, R.S. [Hopkinson Laboratory, Department of Engineering, University of Cambridge (United Kingdom)

    2010-06-15

    A parametric study of forced ignition at the mixing layer between air and air carrying fine monosized fuel droplets is done through one-step chemistry direct numerical simulations to determine the influence of the size and volatility of the droplets, the spark location, the droplet-air mixing layer initial thickness and the turbulence intensity on the ignition success and the subsequent flame propagation. The propagation is analyzed in terms of edge flame displacement speed, which has not been studied before for turbulent edge spray flames. Spark ignition successfully resulted in a tribrachial flame if enough fuel vapour was available at the spark location, which occurred when the local droplet number density was high. Ignition was achieved even when the spark was offset from the spray, on the air side, due to the diffusion of heat from the spark, provided droplets evaporated rapidly. Large kernels were obtained by sparking close to the spray, since fuel was more readily available. At long times after the spark, for all flames studied, the probability density function of the displacement speed was wide, with a mean value in the range 0.55-0.75S{sub L}, with S{sub L} the laminar burning velocity of a stoichiometric gaseous premixed flame. This value is close to the mean displacement speed in turbulent edge flames with gaseous fuel. The displacement speed was negatively correlated with curvature. The detrimental effect of curvature was attenuated with a large initial kernel and by increasing the thickness of the mixing layer. The mixing layer was thicker when evaporation was slow and the turbulence intensity higher. However, high turbulence intensity also distorted the kernel which could lead to high values of curvature. The edge flame reaction component increased when the maximum temperature coincided with the stoichiometric contour. The results are consistent with the limited available experimental evidence and provide insights into the processes associated with

  8. Black-and-white photographic chemistry: A reference

    Science.gov (United States)

    Walker, E. D. (Compiler)

    1986-01-01

    This work is intended as a reference of black-and-white photographic chemistry. Included is a basic history of the photographic processes and a complete description of all chemicals used, formulas for the development and fixation process, and associated formulas such as cleaners, hardeners, and toners. The work contains a complete glossary of photographic terms, a trouble-shooting section listing causes and effects regarding photographic film and papers, and various conversion charts.

  9. 3D PHOTOGRAPHS IN CULTURAL HERITAGE

    Directory of Open Access Journals (Sweden)

    W. Schuhr

    2013-07-01

    Full Text Available This paper on providing "oo-information" (= objective object-information on cultural monuments and sites, based on 3D photographs is also a contribution of CIPA task group 3 to the 2013 CIPA Symposium in Strasbourg. To stimulate the interest in 3D photography for scientists as well as for amateurs, 3D-Masterpieces are presented. Exemplary it is shown, due to their high documentary value ("near reality", 3D photography support, e.g. the recording, the visualization, the interpretation, the preservation and the restoration of architectural and archaeological objects. This also includes samples for excavation documentation, 3D coordinate calculation, 3D photographs applied for virtual museum purposes and as educational tools. In addition 3D photography is used for virtual museum purposes, as well as an educational tool and for spatial structure enhancement, which in particular holds for inscriptions and in rock arts. This paper is also an invitation to participate in a systematic survey on existing international archives of 3D photographs. In this respect it is also reported on first results, to define an optimum digitization rate for analog stereo views. It is more than overdue, in addition to the access to international archives for 3D photography, the available 3D photography data should appear in a global GIS(cloud-system, like on, e.g., google earth. This contribution also deals with exposing new 3D photographs to document monuments of importance for Cultural Heritage, including the use of 3D and single lense cameras from a 10m telescope staff, to be used for extremely low earth based airborne 3D photography, as well as for "underwater staff photography". In addition it is reported on the use of captive balloon and drone platforms for 3D photography in Cultural Heritage. It is liked to emphasize, the still underestimated 3D effect on real objects even allows, e.g., the spatial perception of extremely small scratches as well as of nuances in

  10. Observation of a spark channel generated in water with shock wave assistance in plate-to-plate electrode configuration

    Energy Technology Data Exchange (ETDEWEB)

    Stelmashuk, V., E-mail: vitalij@ipp.cas.cz [Institute of Plasma Physics, Za Slovankou 3, 182 00 Prague 8 (Czech Republic)

    2014-01-15

    When a high voltage pulse with an amplitude of 30 kV is applied to a pair of disk electrodes at a time when a shock wave is passing between them, an electrical spark is generated. The dynamic changes in the spark morphology are studied here using a high-speed framing camera. The primary result of this work is the provision of experimental evidence of plasma instability that was observed in the channel of the electric spark.

  11. Internal combustion engines a detailed introduction to the thermodynamics of spark and compression ignition engines, their design and development

    CERN Document Server

    Benson, Rowland S

    1979-01-01

    Internal Combustion of Engines: A Detailed Introduction to the Thermodynamics of Spark and Compression Ignition Engines, Their Design and Development focuses on the design, development, and operations of spark and compression ignition engines. The book first describes internal combustion engines, including rotary, compression, and indirect or spark ignition engines. The publication then discusses basic thermodynamics and gas dynamics. Topics include first and second laws of thermodynamics; internal energy and enthalpy diagrams; gas mixtures and homocentric flow; and state equation. The text ta

  12. 8 CFR 236.5 - Fingerprints and photographs.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Fingerprints and photographs. 236.5 Section... to Order of Removal § 236.5 Fingerprints and photographs. Every alien 14 years of age or older... photographs shall be made available to Federal, State, and local law enforcement agencies upon request to the...

  13. Best of Adobe Photoshop techniques and images from professional photographers

    CERN Document Server

    Hurter, Bill

    2006-01-01

    Bill Hurter is the editor of ""Rangefinder"" magazine, the former editor of ""Petersen's PhotoGraphic,"" and the author of ""The Best of Wedding Photography, Group Portrait Photography Handbook, The Portrait Photographer's Guide to Posing, ""and ""Portrait Photographer's Handbook. ""He lives in Santa Monica, California.

  14. The aesthetic appeal of depth of field in photographs

    NARCIS (Netherlands)

    Zhang, T.; Nefs, H.T.; Redi, J.; Heynderickx, I.E.J.

    2014-01-01

    We report here how depth of field (DOF) affects the aesthetic appeal of photographs for different content categories. 339 photographs spanning eight categories were selected from Flickr, Google+, and personal collections. First, we classified the 339 photographs into three levels of depth of field:

  15. Using Photographs to Integrate Liberal Arts Learning in Business Education

    Science.gov (United States)

    Madden, Laura T.; Smith, Anne D.

    2015-01-01

    The inclusion of photographic approaches in the business classroom can incorporate missing elements of liberal education into business education, which were highlighted in a recent Carnegie study of undergraduate business education. Building on photographic methods in social science research, we identify three categories of photographic approaches…

  16. 7 CFR 500.9 - Photographs for news or advertising.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Photographs for news or advertising. 500.9 Section 500... for news or advertising. Photographs for news purposes may be taken at the USNA without prior permission. Photographs for advertising and other commercial purposes may be taken, but only with the prior...

  17. Images of the Great Depression: A Photographic Essay.

    Science.gov (United States)

    Stevens, Robert L.; Fogel, Jared A.

    2001-01-01

    Provides background information on the Farm Security Administration (FSA) and the photographic section of the FSA. Identifies six photographers and features three photographers (Walker Evans, Dorothea Lange, and Ben Shahn) who were recruited to document farm conditions. Discusses using FSA photos in the classroom and provides lesson plans to help…

  18. Recognition Memory for Movement in Photographs: A Developmental Study.

    Science.gov (United States)

    Futterweit, Lorelle R.; Beilin, Harry

    1994-01-01

    Investigated whether children's recognition memory for movement in photographs is distorted forward in the direction of implied motion. When asked whether the second photograph was the same as or different from the first, subjects made more errors for test photographs showing the action slightly forward in time, compared with slightly backward in…

  19. Venturi vacuum systems for hypobaric chamber operations.

    Science.gov (United States)

    Robinson, R; Swaby, G; Sutton, T; Fife, C; Powell, M; Butler, B D

    1997-11-01

    Physiological studies of the effects of high altitude on man often require the use of a hypobaric chamber to simulate the reduced ambient pressures. Typical "altitude" chambers in use today require complex mechanical vacuum systems to evacuate the chamber air, either directly or via reservoir system. Use of these pumps adds to the cost of both chamber procurement and maintenance, and service of these pumps requires trained support personnel and regular upkeep. In this report we describe use of venturi vacuum pumps to perform the function of mechanical vacuum pumps for human and experimental altitude chamber operations. Advantages of the venturi pumps include their relatively low procurement cost, small size and light weight, ease of installation and plumbing, lack of moving parts, and independence from electrical power sources, fossil fuels and lubricants. Conversion of three hyperbaric chambers to combined hyper/hypobaric use is described.

  20. Proportional chamber with data analog output

    International Nuclear Information System (INIS)

    Popov, V.E.; Prokof'ev, A.N.

    1977-01-01

    A proportional multiwier chamber is described. The chamber makes it possible to determine angles at wich a pion strikes a polarized target. A delay line, made of 60-core flat cable is used for removing signals from the chamber. From the delay line, signals are amplified and successively injected into shapers and a time-to-amplitude converter. An amplitude of the time-to amplitude converter output signal unambiguously determines the coordinate of a point at which a particle strikes the chamber plane. There are also given circuits of amplifiers, which consist of a preamplifier with gain 30 and a main amplifier with adjustable gain. Data on testing the chamber with the 450 MeV pion beam is demonstrated. The chamber features an efficiency of about 98 per cent under load of 2x10 5 s -1