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Sample records for bakelite resistive plate

  1. Study of Performance of Bakelite Resistive Plate Chamber (RPC)

    CERN Document Server

    Ganai, R; Roy, A; Muduli, B; Chattopadhyay, S; Ahammed, Z; Das, G; Ramnarayan, S

    2016-01-01

    Resistive Plate Chamber (RPC) is a type of gaseous detector having excellent time and position resolutions. VECC is involved in the R\\&D of indigenously developed bakelite RPCs. The largest size of bakelite RPC developed in India is 100 cm $\\times$ 100 cm. We present here the test results of a bakelite sample along with the cosmic ray test results of a bakelite RPC (30 cm $\\times$ 30 cm $\\times$ 0.2cm) fabricated at VECC. The steps taken towards the development of a large size (240 cm $\\times$ 120 cm $\\times$ 0.2 cm) bakelite RPC have also been discussed.

  2. Study of Performance of Bakelite Resistive Plate Chamber (RPC)

    OpenAIRE

    Ganai, R.; Agarwal, K.; Roy, A; Muduli, B.; Chattopadhyay, S; Ahammed, Z.; G Das; Ramnarayan, S.

    2016-01-01

    Resistive Plate Chamber (RPC) is a type of gaseous detector having excellent time and position resolutions. VECC is involved in the R\\&D of indigenously developed bakelite RPCs. The largest size of bakelite RPC developed in India is 100 cm $\\times$ 100 cm. We present here the test results of a bakelite sample along with the cosmic ray test results of a bakelite RPC (30 cm $\\times$ 30 cm $\\times$ 0.2cm) fabricated at VECC. The steps taken towards the development of a large size (240 cm $\\times...

  3. Development of linseed oil-free bakelite resistive plate chambers

    CERN Document Server

    Biswas, S; Bose, S; Chattopadhyay, S; Saha, S; Viyogi, Y P

    2009-01-01

    In this paper we would like to present a few characteristics of the Resistive Plate Chambers (RPC) made of a particular grade of bakelite paper laminates (P-120, NEMA LI-1989 Grade XXX), produced and commercially available in India. This particular grade is used for high voltage insulation in humid conditions. The chambers are tested with cosmic rays in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio. In the first set of detectors made with such grade, a thin coating of silicone fluid on the inner surfaces of the bakelite was found to be necessary for operation of the detector. Those silicone coated RPCs were found to give satisfactory performance with stable efficiency of >90% continuously for a long period as reported earlier. Results of the crosstalk measurement of these silicone coated RPC will be presented in this paper. Very recently RPCs made with the same grade of bakelite but having better surface finish, are found to give equivalent performance even without any ...

  4. Temperature and humidity dependence of bulk resistivity of bakelite for resistive plate chambers in CMS

    International Nuclear Information System (INIS)

    This paper presents data obtained in a systematic study on the bulk resistivity of Korean bakelite as a function of temperature in the range 20-30 deg. C and relative humidity in the range 35-65%. Strong dependence of resistivity on both temperature and humidity was observed. Measurements were carried out in the framework of R and D work on Resistive Plate Chambers (RPCs) which will be used in the CMS detector

  5. Fabrication and Characterisation of Oil-Free Large Bakelite Resistive Plate Chamber

    CERN Document Server

    Ganai, Rajesh; Agarwal, Kshitij; Ahammed, Zubayer; Choudhury, Subikash; Chattopadhyay, Subhasis

    2015-01-01

    A large (240 cm $\\times$ 120 cm $\\times$ 0.2 cm) oil-free bakelite Resistive Plate Chamber (RPC) has been developed at VECC-Kolkata using locally available P-301 OLTC grade bakelite paper laminates. The chamber has been operated in streamer mode using Argon, Freon(R134a) and Iso-butane in a ratio of 34:57:9 by volume. The electrodes and glue samples were characterised by measuring their electrical parameters like bulk resistivity and surface resistivity. The performance of the chamber was studied by measuring the efficiency, time resolution and uniformity in detection of cosmic muons. The chamber showed an efficiency $>$95$\\%$ and time resolution ($\\sigma$) of $\\sim$0.83 ns. Details of the material characterisation, fabrication procedure and performance studies have been discussed.

  6. Temperature and humidity dependence of bulk resistivity of bakelite for resistive plate chambers in CMS

    CERN Document Server

    Ahn, S H; Bahk, S Y; Gapienko, V A; Hong, B; Hong, S J; Jung, S Y; Kim, J Y; Kim, Y J; Kim, Y U; Koo, D G; Lee, K S; Lee, S J; Lee, Y L; Lim, I T; Nam, S K; Pac, M Y; Park, S K; Ra, Y S; Rhee, J T; Seo, S W; Sim, K S

    2000-01-01

    This paper presents data obtained in a systematic study on the bulk resistivity of Korean bakelike as a function of temperature in the range 20-30 degrees C and relative humidity in the range 35-65%. Strong dependence of resistivity on both temperature and humidity was observed. Measurements were carried out in the framework of R&D work on resistive plate chambers which will be used in the CMS detector. (4 refs).

  7. Long Term Performance Studies of Large Oil-Free Bakelite Resistive Plate Chamber

    CERN Document Server

    Ganai, Rajesh; Shiroya, Mehul Kumar; Agarwal, Kshitij; Ahammed, Zubayer; Choudhury, Subikash; Chattopadhyay, Subhasis

    2016-01-01

    Several high energy physics and neutrino physics experiments worldwide require large-size RPCs to cover wide acceptances. The muon tracking systems in the Iron calorimeter (ICAL) in the INO experiment, India and the near detector in DUNE at Fermilab are two such examples. A (240 cm $\\times$ 120 cm $\\times$ 0.2 cm) bakelite RPC has been built and tested at Variable Energy Cyclotron Centre, Kolkata, using indigenous materials procured from the local market. No additional lubricant, like oil has been used on the electrode surfaces for smoothening. The chamber is in operation for $>$ 365 days. We have tested the chamber for its long term operation. The leakage current, bulk resistivity, efficiency, noise rate and time resolution of the chamber have been found to be quite stable during the testing peroid. It showed an efficiency $>$ 95$\\%$ with an average time resolution of $\\sim$0.83 ns at the point of measurement at 9000 V throughout the testing period. Details of the long term performance of the chamber have be...

  8. Influence of Temperature and Humidity on Bakelite Resistivity

    CERN Document Server

    Arnaldi, R; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; Dellacasa, G; De Marco, N; Dupieux, P; Espagnon, B; Fargeix, J; Ferretti, A; Gallio, M; Lamoine, L; Luquin, Lionel; Manso, F; Mereu, P; Métivier, V; Musso, A; Oppedisano, C; Piccotti, A; Rahmani, A; Royer, L; Roig, O; Scalas, E; Scomparin, E; Vercellin, Ermanno

    1999-01-01

    Presentation made at RPC99 and submitted to Elsevier PreprintThe use of phenolic or melaminic bakelite as RPC electrodes is widespread. The electrode resistivity is an important parameter for the RPC performance. As recent studies have pointed out, the bakelite resistivity changes with temperature and is influenced by humidity. In order to gain a quantitative understanding on the influence of temperature and humidity on RPC electrodes, we assembled an apparatus to measure resistivity in well-controlled conditions. A detailed description of the experimental set-up as well as the first resistivity measurements for various laminates in different environmental conditions are presented.

  9. Study of Glass and Bakelite Properties as Electrodes in RPC

    CERN Document Server

    Manisha,; Shahi, J S

    2016-01-01

    India-based Neutrino Observatory (INO) collaboration is planning to build a magnetized Iron-CALorimeter detector (ICAL) for the study of atmospheric neutrinos. ICAL detector consists of 151 layers of magnetized iron plates interleaved with Resistive Plate Chambers (RPCs) as active detector elements with a total mass of 50 kton. Resistive Plate Chambers are gaseous detectors made up of two parallel electrodes of high bulk resistivity like float glass and bakelite. These detectors are extensively used in several high energy physics experiments since 1980s because of high count rate, excellent time as well as spatial resolutions, simple to fabricate and operate. Due to detector aging issue, it is necessary to characterize electrode material so as to select appropriate electrode material before fabricating the detector. In the present studies, we measured bulk resistivity and surface current of glass as well as bakelite. Bulk resistivity of bakelite is ~ 100 times less than that of glass and surface current of ba...

  10. Study of Glass and Bakelite properties as electrodes in RPCs

    OpenAIRE

    Manisha,; Bhatnagar, V.; Shahi, J. S.

    2016-01-01

    India-based Neutrino Observatory (INO) collaboration is planning to build a magnetized Iron-CALorimeter detector (ICAL) for the study of atmospheric neutrinos. ICAL detector will be a stack of 151 layers of magnetized iron plates interleaved with Resistive Plate Chambers (RPCs) as active detector elements with a total mass of 50 kton. Resistive Plate Chambers are gaseous detectors made up of two parallel electrodes of high bulk resistivity like float glass and bakelite. These detectors are ex...

  11. Bakelite chambers for time-of-flight measurements

    CERN Document Server

    Cwiok, M; Górski, M; Królikowski, J

    1999-01-01

    We report on the search of composite organic materials with the volume resistivity ranging from 10 sup 8 to 10 sup 1 sup 1 OMEGA cm. Materials having resistivity in this range may be used for electrodes of thin gap Parallel Plate Avalanche Chambers. Gas detectors of such structure and operated at increased gas pressure allow, potentially, a sub-nanosecond time resolution. Using bakelite-like material with electrical properties well tuned during manufacturing opens the possibility to overcome limitations related to the semi-conductive glass employed usually for ultrafast gas detectors of parallel plate structure for time-of-flight technique.

  12. OPERA Resistive Plate Chambers underground test results

    Energy Technology Data Exchange (ETDEWEB)

    Bergnoli, A. [Padova University and INFN, Padova (Italy); Brugnera, R. [Padova University and INFN, Padova (Italy); Candela, A. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Carrara, E. [Padova University and INFN, Padova (Italy); Ciesielski, R. [Padova University and INFN, Padova (Italy); Dal Corso, F. [Padova University and INFN, Padova (Italy); Degli Esposti, L. [Bologna University and INFN, Bologna (Italy); Di Giovanni, A. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); D' Incecco, M. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Di Troia, C. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Dusini, S. [Padova University and INFN, Padova (Italy); Fanin, C. [Padova University and INFN, Padova (Italy); Felici, G. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gambarara, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Garfagnini, A. [Padova University and INFN, Padova (Italy); Gatta, M.; Grianti, F. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gustavino, C.; Lindozzi, M. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Longhin, A. [Padova University and INFN, Padova (Italy)]. E-mail: longhin@pd.infn.it; Mengucci, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Monacelli, P. [L' Aquila University and INFN, l' Aquila (Italy)]|[INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Paoloni, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Stanco, L. [Padova University and INFN, Padova (Italy); Tatananni, E. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Terranova, F.; Spinetti, M. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Stipcevic, M.; Sugonyaev, V. [Rudjer Boskovic Institute (IRB), Zagreb (Croatia); Terminiello, L.; Ventura, M.; Votano, L. [INFN Laboratori Nazionali di Frascati, Frascati (Italy)

    2006-08-15

    The OPERA experiment [M. Guler et al., CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000, July 10, 2000; M. Guler et al., CERN/SPSC 2001-025, SPSC/M668, LNGS-EXP 30/2001 Add. 1/01, August 21, 2001] will study {nu}{sub {mu}}->{nu}{sub {tau}} oscillations through {tau} appearance on the 732 Km long CERN to Gran Sasso baseline. The magnet yokes of the two muon spectrometers are instrumented with 44 layers of high resistivity bakelite Resistive Plate Chambers (RPCs) operated in streamer mode. Each layer covers about 70 m{sup 2}. Four RPC planes were instrumented and the first tests were performed confirming a good behaviour of the installed RPCs in terms of intrinsic noise and operating currents. The measured noise maps agree with those obtained in the extensive quality tests performed at surface. Counting rates are below 20 Hz/m{sup 2}. Single an multiple cosmic muon tracks were also reconstructed. The estimated efficiency is close to the geometrical limit and the very first measurements of the absolute and differential muon flux are in agreement with expectations.

  13. OPERA Resistive Plate Chambers underground test results

    International Nuclear Information System (INIS)

    The OPERA experiment [M. Guler et al., CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000, July 10, 2000; M. Guler et al., CERN/SPSC 2001-025, SPSC/M668, LNGS-EXP 30/2001 Add. 1/01, August 21, 2001] will study νμ->ντ oscillations through τ appearance on the 732 Km long CERN to Gran Sasso baseline. The magnet yokes of the two muon spectrometers are instrumented with 44 layers of high resistivity bakelite Resistive Plate Chambers (RPCs) operated in streamer mode. Each layer covers about 70 m2. Four RPC planes were instrumented and the first tests were performed confirming a good behaviour of the installed RPCs in terms of intrinsic noise and operating currents. The measured noise maps agree with those obtained in the extensive quality tests performed at surface. Counting rates are below 20 Hz/m2. Single an multiple cosmic muon tracks were also reconstructed. The estimated efficiency is close to the geometrical limit and the very first measurements of the absolute and differential muon flux are in agreement with expectations

  14. Oxygen ion implantation induced microstructural changes and electrical conductivity in Bakelite RPC detector material

    Science.gov (United States)

    Kumar, K. V. Aneesh; Ranganathaiah, C.; Kumarswamy, G. N.; Ravikumar, H. B.

    2016-05-01

    In order to explore the structural modification induced electrical conductivity, samples of Bakelite Resistive Plate Chamber (RPC) detector materials were exposed to 100 keV Oxygen ion in the fluences of 1012, 1013, 1014 and 1015 ions/cm2. Ion implantation induced microstructural changes have been studied using Positron Annihilation Lifetime Spectroscopy (PALS) and X-Ray Diffraction (XRD) techniques. Positron lifetime parameters viz., o-Ps lifetime and its intensity shows the deposition of high energy interior track and chain scission leads to the formation of radicals, secondary ions and electrons at lower ion implantation fluences (1012 to1014 ions/cm2) followed by cross-linking at 1015 ions/cm2 fluence due to the radical reactions. The reduction in electrical conductivity of Bakelite detector material is correlated to the conducting pathways and cross-links in the polymer matrix. The appropriate implantation energy and fluence of Oxygen ion on polymer based Bakelite RPC detector material may reduce the leakage current, improves the efficiency, time resolution and thereby rectify the aging crisis of the RPC detectors.

  15. Study of RPC bakelite electrodes and detector performance for INO-ICAL

    CERN Document Server

    Kumar, Ashok; Hasbuddin, Md; Kumar, Praveen; Kumar, Purnendu; Kaur, Daljeet; Mishra, Swati; Naimuddin, Md

    2014-01-01

    The Resistive Plate Chambers (RPCs) are going to be used as the active detectors in the India-based Neutrino Observatory (INO)-Iron Calorimeter (ICAL) experiment for the detection and study of atmospheric neutrinos. In this paper, an extensive study of structural and electrical properties for different kind of bakelite RPC electrodes is presented. RPCs fabricated from these electrodes are tested for their detector efficiency and noise rate. The study concludes with the variation of efficiency, leakage current and counting rate over the period of operation with different gas compositions and operational conditions like temperature and relative humidity.

  16. Development of Multi-gap Resistive Plate Chamber (MRPC) for medical imaging

    CERN Document Server

    Banerjee, A; Biswas, S; Chattopadhyay, S; Das, G; Pal, S

    2014-01-01

    The low cost and high resolution Multi-gap Resistive Plate Chamber (MRPC) opens up a new possibility to find an efficient alternative detector for the Time of Flight (TOF) based Positron Emission Tomography, where the sensitivity of the system depends largely on the time resolution of the detector. In a layered structure, suitable converters can be used to increase the photon detection efficiency. In this paper results of the cosmic ray test of a four-gap bakelite-based prototype MRPC operated in streamer mode and six-gap glass-based MRPC operated in avalanche mode are discussed.

  17. The bakelite for the RPCs of the experiment CMS

    OpenAIRE

    Altieri, S.; Bruno, Giacomo Luca

    2000-01-01

    Results from aging tests on the bakelite used for the CMS RPCs are presented. Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation. Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles fluence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS. The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci 137Cs source. A total abso...

  18. CMS Resistive plate Champers

    CERN Document Server

    Zainab, Karam

    2013-01-01

    There are many types of gas detectors which are used in CERN in LHC project, There is a main parts for the gas detectors which must be in all gas detectors types like Multiwire proportional chambers, such as the micromesh gaseous structure chamber (the MicroMegas), Gas-electron multiplier (GEM) detector, Resistive Plate Champers... Compact Muon Solenoid (CMS) experiment detecting muons which are powerful tool for recognizing signatures of interesting physics processes. The CMS detector uses: drift tube (DT), cathode strip chamber (CSC) and resistive plate chamber (RPC). Building RPC’s was my project in summer student program (hardware). RPC’s have advantages which are triggering detector and Excellent time resolution which reinforce the measurement of the correct beam crossing time. RPC’s Organized in stations :  RPC barrel (RB) there are 4 stations, namely RB1, RB2, RB3, and RB4  While in the RPC endcap (RE) the 3 stations are RE1, RE2, and RE3. In the endcaps a new starion will be added and this...

  19. The multigap resistive plate chamber

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-03

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

  20. Performance and simulation of a double-gap resistive plate chamber in the avalanche mode

    CERN Document Server

    Ahn Sung Hwan; Hong Byung Sik; Hong Seong Jong; Ito, M; Kang, T I; Kim, B I; Kim, J H; Kim, Y J; Kim, Y U; Koo, D G; Lee Hyup Woo; Lee, K B; Lee Kyong Sei; Lee Seok Jae; Lim, J K; Moon, D H; Nam, S K; Park, S; Park, W J; Rhee June Tak; Ryu, M S; Sim Kwang Souk

    2004-01-01

    We present a detailed analysis of the time and the charge signals of a prototype double-gap resistive plate chamber for the endcap region of the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The chamber was built with relatively low-resistivity bakelite. The time and the charge results demonstrate that the high- voltage plateau, which satisfies various CMS requirements for the efficiency, the noise cluster rate, the fraction of the large signal, and the streamer probability, can be extended at least up to 400 V with the present design. In addition, a simple avalanche multiplication model is studied in detail. The model can reproduce the experimental charge spectra reasonably well. The charge information enables us to estimate the effective Townsend coefficient in avalanche-mode operation.

  1. Corrosion resistant metallic bipolar plate

    Science.gov (United States)

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  2. Highly efficient resistive plate chambers for high rate environment

    International Nuclear Information System (INIS)

    The full scale prototype of an Inverted Double Gap RPC module for ME-1/1 station of the CMS detector was tested in the Gamma Irradiation Facility at the CERN SPS muon beam. The chamber made of medium resistivity bakelite and filled with 'green gas' mixture of C2H2F4/iso-butane/SF6 has wide efficiency plateau and good timing properties when operated in avalanche mode under continuous irradiation with strong 137Cs source for rates up to about 5 kHz/cm2/gap

  3. The bakelite for the RPCs of the experiment CMS

    Science.gov (United States)

    Altieri, S.; Belli, G.; Bruno, G.; Guida, R.; Merlo, M.; Ratti, S. P.; Riccardi, C.; Torre, P.; Vitulo, P.; Mognaschi, E. R.; Abbrescia, M.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Ranieri, A.; Romano, F.

    2000-12-01

    Results from aging tests on the bakelite used for the CMS RPCs are presented. Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation. Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles fluence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS. The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci 137Cs source. A total absorbed dose of 5 Gy was accumulated during an irradiation period of about one month. The test with both neutron and gamma radiation was held at the Triga Mark II 250 kW reactor located in Pavia. A total of 80 h of exposure were accumulated integrating a neutron and gamma dose of about 80 Gy and a fast neutron fluence of some 10 11 cm-2. Experimental data on dose rate in both the test facilities have been compared to simulation output and show a good agreement.

  4. The bakelite for the RPCs of the experiment CMS

    CERN Document Server

    Altieri, S; Bruno, G; Guida, R; Merlo, M; Ratti, S P; Riccardi, C; Torre, P; Vitulo, P; Mognaschi, E R; Abbrescia, M; Colaleo, A; Iaselli, Giuseppe; Loddo, F; Maggi, M; Marangelli, B; Natali, S; Nuzzo, S; Pugliese, G; Ranieri, A; Romano, F

    2000-01-01

    Results from aging tests on the bakelite used for the CMS RPCs are presented. Samples of melaminic bakelite were exposed to a heavy gamma and neutron radiation. Data on the bulk resistivity were collected while accumulating gamma and neutron doses and particles fluence up to values well beyond those expected in 10 years of RPCs operation in the barrel region of CMS. The test with gamma radiation was performed at the CERN Gamma Irradiation Facility (GIF) with a 20 Ci /sup 137/Cs source. A total absorbed dose of 5 Gy was accumulated during an irradiation period of about one month. The test with both neutron and gamma radiation was held at the Triga Mark II 250 kW reactor located in Pavia. A total of 80 h of exposure were accumulated integrating a neutron and gamma dose of about 80 Gy and a fast neutron fluence of some 10/sup 11/ cm/sup -2/. Experimental data on dose rate in both the test facilities have been compared to simulation output and show a good agreement. (4 refs).

  5. Beam test results of the first full-scale prototype of CMS RE 1/2 Resistive Plate Chamber

    CERN Document Server

    Ying, Jun; Cai Jian Xin; Liu Hong Tao; Qian Si Jin; Wang Quan Jin; Ye Yan Lin

    2005-01-01

    We reported the muon beam test results of the first full-scale prototype of CMS RE 1/2 Resistive Plate Chamber (RPC). The bakelite surface is treated using a special technology without oil to make it smooth enough. The full scale RE 1/2 RPC with honeycomb supporting frame is strong and thin enough to be fitted to the limited space of CMS design for the inner Forward RPC. The muon beam test was performed at CERN Gamma Irradiation Facility (GIF). The detection efficiency of this full scale RPC prototype is >95% even at very high irradiation background. The time resolution (less than 1.2 ns) and spatial resolution are satisfactory for the muon trigger device in future CMS experiments. The noise rate is also calculated and discussed.

  6. Mechanisms affecting performance of the BaBar resistive plate chambers and searches for remediation

    International Nuclear Information System (INIS)

    The BaBar experiment at PEPII relies on the instrumentation of the flux return (IFR) for both muon identification and KL detection. The active detector is composed of resistive plate chambers (RPCs) operated in streamer mode. Since the start of operation the RPCs have suffered persistent efficiency deterioration and dark current increase problems. The 'autopsy' of bad BaBar RPCs revealed that in many cases uncured linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil 'stalagmites' bridging the 2 mm gap. In this paper, a possible model of this 'stalagmite' formation and its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently, the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement

  7. Recycling Waste Bakelite As A Carbon Resource In Ironmaking

    Directory of Open Access Journals (Sweden)

    James Ransford Dankwah

    2015-02-01

    Full Text Available Abstract Bakelite is a 3-dimensional cross-linked network structured thermosetting polymer which is difficult to recycle after use. However it contains high levels of carbon and CaCO3 that can be recovered for use as reductant and fluxing agent in ironmaking. In this work we report the use of post-consumer bakelite as reductant for the production of metallic iron from iron oxide in a horizontal tube furnace through the composite pellet approach.Gas emission studies were conducted by pyrolysing raw bakelite at different temperatures within the temperature range 1200-1600 C in a horizontal tube furnace. Following thiscomposite pellets were then formed from mixtures of iron oxide and post-consumer bakelite.The iron oxide-bakelite composites were heated from room temperature to 1200 C and then between 1200-1600 C in a continuous stream of pure argon and the off gas was analysed continuously using an infrared IR gas analyser. Elemental analyses of samples of the reduced metal were performed chemically for its oxygen content using a LECO oxygennitrogen analyser. The extent of reduction after ten minutes was determined from the oxygen content. Gas emission studies revealed the emission of large volumes of the reductant gases CO and CH4along with CO2.It is further demonstrated that post-consumer bakelite is effective at reducing iron oxide to produce metallic iron.

  8. Progress in timing Resistive Plate Chambers

    OpenAIRE

    Blanco, A.; Carolino, N.; Correia, C. M. B. A.; Ferreira-Marques, R.; P. Fonte(LIP-Laboratório de Instrumentação e Física Experimental de Partículas, Portugal); Gobbi, A.; González-Díaz, D.; Lopes, M.I.; Lopes, L.; Macedo, M. P.; Mangiarotti, A.; V. Peskov; Policarpo, A.

    2004-01-01

    Timing RPCs are Resistive Plate Chambers made with glass and metal electrodes separated by precision spacers. Typical gas gaps are a few hundred micrometers wide. Such counters were introduced in 1999 and have since reached timing accuracies below 50 ps [sigma] with efficiencies above 99% for MIPs. Applications in high-energy physics have already taken place with several more under study.

  9. Development and progress in resistive plate chamber

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-Fang; WU Jian

    2004-01-01

    Resistive Plate Chamber (RPC) is a robust and low cost gas detector, which is extensively used in high-energy physics, cosmic and astroparticle physics experiments. Over the past twenty years, as a particle detector,RPC has made remarkable progress. The main achievements, features and results of experiemantal tests including R&D and production of the RPCs by several Chinese groups in recent years are reported in this article.

  10. Angular resolution of stacked resistive plate chambers

    CERN Document Server

    Samuel, Deepak; Murgod, Lakshmi P

    2016-01-01

    We present here detailed derivations of mathematical expressions for the angular resolution of a set of stacked resistive plate chambers (RPCs). The expressions are validated against experimental results using data collected from the prototype detectors (without magnet) of the upcoming India-based Neutrino Observatory (INO). In principle, these expressions can be used for any other detector with an architecture similar to that of RPCs.

  11. A very large multigap resistive plate chamber

    CERN Document Server

    Cerron-Zeballos, E; Hatzifotiadou, D; Kim, D W; Lamas-Valverde, J; Lee, S C; Platner, E D; Roberts, J; Williams, M C S; Zichichi, A

    1999-01-01

    We have built and tested a very large multigap resistive plate chamber (MRPC). We discuss the suitability of the multigap RPC for the construction of large area modules. We give details of the construction technique and results from a scan across the surface of the chamber. We also report on the implementation of `half-strip resolution', where we improve the spatial resolution by a factor 2 without increasing the number of read-out channels. (9 refs).

  12. Timing Resistive Plate Chambers with Ceramic Electrodes

    OpenAIRE

    Laso Garcia, Alejandro

    2015-01-01

    The focus of this thesis is the development of Resistive Plate Chambers (RPCs) with ceramic electrodes. The use of ceramic composites, Si3N4/SiC, opens the way for the application of RPCs in harsh radiation environments. Future Experiments like the Compressed Baryonic Matter (CBM) at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt will need new RPCs with high rate capabilities and high radiation tolerance. Ceramic composites are specially suited for this purpose due to th...

  13. Recycling Waste Bakelite As A Carbon Resource In Ironmaking

    OpenAIRE

    James Ransford Dankwah; Emmanuel Baawuah

    2015-01-01

    Abstract Bakelite is a 3-dimensional cross-linked network structured thermosetting polymer which is difficult to recycle after use. However it contains high levels of carbon and CaCO3 that can be recovered for use as reductant and fluxing agent in ironmaking. In this work we report the use of post-consumer bakelite as reductant for the production of metallic iron from iron oxide in a horizontal tube furnace through the composite pellet approach.Gas emission studies were conducted by pyrolysin...

  14. The physics of Resistive Plate Chambers

    CERN Document Server

    Riegler, Werner

    2004-01-01

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

  15. Detector Physics of Resistive Plate Chambers

    CERN Document Server

    Lippmann, Christian; Riegler, W

    2003-01-01

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

  16. Resistive Plate Chambers: electron transport and modeling

    International Nuclear Information System (INIS)

    We study the electron transport in gas mixtures used by Resistive Plate Chambers (RPCs) in high energy physics experiments at CERN. Calculations are performed using a multi term theory for solving the Boltzmann equation. We identify the effects induced by non-conservative nature of electron attachment, including attachment heating of electrons and negative differential conductivity (NDC). NDC was observed only in the bulk component of drift velocity. Using our Monte Carlo technique, we calculate the spatially resolved transport properties in order to investigate the origin of these effects. We also present our microscopic approach to modeling of RPCs which is based on Monte Carlo method. Calculated results for a timing RPC show good agreement with an analytical model and experimental data. Different cross section sets for electron scattering in C2H2F4 are used for comparison and analysis

  17. Tests of a novel design of Resistive Plate Chambers

    International Nuclear Information System (INIS)

    A novel design of Resistive Plate Chambers (RPCs), using only a single resistive plate, is being proposed. Based on this design, two large size prototype chambers were constructed and were tested with cosmic rays and in particle beams. The tests confirmed the viability of this new approach. In addition to showing an improved single-particle response compared to the traditional 2-plate design, the novel chambers also prove to be suitable for calorimetric applications

  18. Resistive plate chambers in positron emission tomography

    Science.gov (United States)

    Crespo, Paulo; Blanco, Alberto; Couceiro, Miguel; Ferreira, Nuno C.; Lopes, Luís; Martins, Paulo; Ferreira Marques, Rui; Fonte, Paulo

    2013-07-01

    Resistive plate chambers (RPC) were originally deployed for high energy physics. Realizing how their properties match the needs of nuclear medicine, a LIP team proposed applying RPCs to both preclinical and clinical positron emission tomography (RPC-PET). We show a large-area RPC-PET simulated scanner covering an axial length of 2.4m —slightly superior to the height of the human body— allowing for whole-body, single-bed RPC-PET acquisitions. Simulations following NEMA (National Electrical Manufacturers Association, USA) protocols yield a system sensitivity at least one order of magnitude larger than present-day, commercial PET systems. Reconstruction of whole-body simulated data is feasible by using a dedicated, direct time-of-flight-based algorithm implemented onto an ordered subsets estimation maximization parallelized strategy. Whole-body RPC-PET patient images following the injection of only 2mCi of 18-fluorodesoxyglucose (FDG) are expected to be ready 7 minutes after the 6 minutes necessary for data acquisition. This compares to the 10-20mCi FDG presently injected for a PET scan, and to the uncomfortable 20-30minutes necessary for its data acquisition. In the preclinical field, two fully instrumented detector heads have been assembled aiming at a four-head-based, small-animal RPC-PET system. Images of a disk-shaped and a needle-like 22Na source show unprecedented sub-millimeter spatial resolution.

  19. Impact resistance of composite laminated sandwich plates

    Science.gov (United States)

    Kim, Chun-Gon; Jun, Eui-Jin

    1992-01-01

    Investigated are the effects of face layup sequence and core density of a sandwich plate on the impact delamination area of the laminated facesheet. The sandwich plate is made of graphite/epoxy faces and Nomex honeycomb core. The size and shape of delamination due to impact at each interply location have been measured by the room temperature deply technique. The shape of the interply delamination under impact is, in general, found to be two-lobed. The shape exhibits very peculiar regularity under various experimental conditions. The quantitative measurement of delamination size has shown that the face layup with small relative orientation between adjacent plies and high density core are desirable in sandwich plates to reduce the impact delamination.

  20. Improved Corrosion Resistance of Pulse Plated Nickel through Crystallisation Control

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Watanabe, Tohru; Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers

    1995-01-01

    When electrodeposition of nickel is used for corrosion protection of steel two aspects are important. The porosity of the coating and the resistance against corrosion provided by the coating itself. Using simple pulsed current (PC) plating, the size of the deposited crystals can be significantly...... smaller, thereby reducing porosity correspondingly. This usually also leads to improved hardness of the coating. Introducing pulse reversal (PR) plating, the most active crystals are continuously dissolved during the anodic pulse, providing a coating with improved subsequent corrosion resistance in almost...... any corrosive environment. This correlation between film texture and corrosion resistance will be discussed....

  1. Study of the molecular structure and dynamics of bakelite with neutron cross section measurements

    International Nuclear Information System (INIS)

    The molecular structure and dynamics of calcined bakelite were studied with neutron transmission and scattering cross section measurements. The total cross sections determined were correlated with data obtained with infra-red spectroscopy, elemental analysis and other techniques to get the probable molecular formulae of bakelite. The total cross section determined showed a deviation smaller than 5% from the literature values. The frequency distribution as well as overall experimental results allowed to suggest a structural model like polycyclic hydrocarbons for bakelite calcined at 8000 C. (F.E.). 65 refs, 31 figs, 5 tabs

  2. A low-resistivity RPC for the ALICE dimuon arm

    International Nuclear Information System (INIS)

    In view of ALICE, the dedicated Heavy-Ion Experiment at LHC, a Resistive Plate Chamber (RPC) with electrodes made of low-resistivity bakelite (ρ≅3.5x109 Ω cm) has been tested at the CERN SPS both in streamer and in avalanche mode. The chamber has shown a stable behaviour and excellent rate capability: its efficiency is better than 95% for local particle fluxes of about 1 and 10 kHz/cm2 for operation in streamer and in avalanche mode, respectively. The cluster size and the time resolution have also been measured for both modes of operation

  3. Observation of light from resistive plate chambers

    International Nuclear Information System (INIS)

    Electrically induced signals and light emissions from restrictive plate chamber (RPC) are simultaneously measured using a glass RPC with transparent high-voltage planes, operating in the streamer mode. With one exception, good correspondence is seen in between the electrical and optical signals in every aspect: signal shapes, pulse heights, timing and afterpulses. The one exception is a possible limiting effect observed on the optical signal pulse height for a given pulse height of electrically induced signal. Shapes of the signal visually observed by eye are also described. (orig.)

  4. Impact and Blast Resistance of Sandwich Plates

    Science.gov (United States)

    Dvorak, George J.; Bahei-El-Din, Yehia A.; Suvorov, Alexander P.

    Response of conventional and modified sandwich plate designs is examined under static load, impact by a rigid cylindrical or flat indenter, and during and after an exponential pressure impulse lasting for 0.05 ms, at peak pressure of 100 MPa, simulating a nearby explosion. The conventional sandwich design consists of thin outer (loaded side) and inner facesheets made of carbon/epoxy fibrous laminates, separated by a thick layer of structural foam core. In the three modified designs, one or two thin ductile interlayers are inserted between the outer facesheet and the foam core. Materials selected for the interlayers are a hyperelas-tic rate-independent polyurethane;a compression strain and strain rate dependent, elastic-plastic polyurea;and an elastomeric foam. ABAQUS and LS-Dyna software were used in various response simulations. Performance comparisons between the enhanced and conventional designs show that the modified designs provide much better protection against different damage modes under both load regimes. After impact, local facesheet deflection, core compression, and energy release rate of delamination cracks, which may extend on hidden interfaces between facesheet and core, are all reduced. Under blast or impulse loads, reductions have been observed in the extent of core crushing, facesheet delaminations and vibration amplitudes, and in overall deflections. Similar reductions were found in the kinetic energy and in the stored and dissipated strain energy. Although strain rates as high as 10-4/s1 are produced by the blast pressure, peak strains in the interlayers were too low to raise the flow stress in the polyurea to that in the polyurethane, where a possible rate-dependent response was neglected. Therefore, stiff polyurethane or hard rubber interlayers materials should be used for protection of sandwich plate foam cores against both impact and blast-induced damage.

  5. Resistive plate chambers for time-of-flight measurements

    International Nuclear Information System (INIS)

    The applications of Resistive Plate Chambers (RPCs) have recently been extended by the development of counters with time resolution below 100 ps σ for minimum ionising particles. Applications to HEP experiments have already taken place and many further applications are under study. In this work, we address the operating principles of such counters along with some present challenges, with emphasis on counter ageing. Possible applications to radioisotope imaging will be outlined

  6. Data Quality Monitoring for the CMS Resistive Plate Chamber Detector

    Science.gov (United States)

    Cimmino, A.; CMS Collaboration

    2011-06-01

    Resistive Plate Chambers (RPCs), with their excellent time resolution (˜ 2 ns), were chosen as dedicated muon trigger detectors for the CMS experiment. RPCs fulfill the job of muon identification, estimate the momentum and unambiguously assign bunch crossing. The critical tasks of monitoring detector performances, debugging hardware, and certifying recorded data are carried out by the RPC Data Quality Monitoring (DQM) system. We here describe the structure, functionalities, and performances of the DQM applications for the CMS RPC detector.

  7. Resistive plate chambers for muon detection at LHC

    Institute of Scientific and Technical Information of China (English)

    叶沿林; 应军; 班勇; 刘洪涛; 蔡建新; 朱子美; 马经国; 陈陶; 钱思进

    2002-01-01

    One resistive plate chamber made of Chinese materials and one Italian resistive platechamber have been tested in the Gamma Irradiation Facility (GIF) at CERN on a high intensitymuon beam together with a 137Cs source to give a uniform photon background, and simulatingconditions close to those expected for an LHC muon detector. The results are analyzed. Goodspace and time resolutions are obtained which satisfy the future CMS experiment requirements.The detection efficiency is different between two RPCs against a high irradiation background. Thereason is discussed.

  8. Molecular dynamical and structural studies for the bakelite by neutron cross section measurements

    International Nuclear Information System (INIS)

    Neutron reaction cross sections were determined by transmission and scattering measurements, to study the dynamics and molecular structure of calcined bakelites. Total cross sections were determined, with a deviation smaller than 5%, from the literature values, by neutron transmission method and a specially devised approximation. These cross sections were then correlated with data obtained with infra-red spectroscopy, elemental analysis and other techniques to get the probable molecular formulae of bakelite. Double differential scattering cross sections, scattering law values and frequency distributions were determined with 15% error using the neutron inelastic scattering method. The frequency distributions as well as the overall results from all experimental techniques used in this work allowed to suggest a structural model like polycyclic hydrocarbons, for calcined bakelite at 8000 C. (author)

  9. HF production in CMS-Resistive Plate Chambers

    International Nuclear Information System (INIS)

    The formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50 x 50 cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition, possible additional impurities as well as fluoride ions have been monitored in different gamma irradiation conditions both in open and closed loop mode. The chemical composition of the RPC electrode surface has also been analyzed using an electron microscope equipped with an EDS/X-ray

  10. Glass resistive plate chambers in the OPERA experiment

    International Nuclear Information System (INIS)

    OPERA is an underground neutrino oscillation experiment to search for ντ appearance from a pure νμ beam produced at CERN. To flag the events due to the neutrino interactions with the rock surrounding the OPERA detector, a large VETO system, based on the use of Glass Resistive Plate Chambers (GRPC) has been realized. We describe the detectors, the tests performed before the installation in the underground laboratories and the monitor system for the water pollution in the GRPC gas mixture

  11. Corrosion-resistant, electrically-conductive plate for use in a fuel cell stack

    Science.gov (United States)

    Carter, J. David; Mawdsley, Jennifer R.; Niyogi, Suhas; Wang, Xiaoping; Cruse, Terry; Santos, Lilia

    2010-04-20

    A corrosion resistant, electrically-conductive, durable plate at least partially coated with an anchor coating and a corrosion resistant coating. The corrosion resistant coating made of at least a polymer and a plurality of corrosion resistant particles each having a surface area between about 1-20 m.sup.2/g and a diameter less than about 10 microns. Preferably, the plate is used as a bipolar plate in a proton exchange membrane (PEMFC) fuel cell stack.

  12. EFFECT OF BAKELITE INTERLAYER POWDER ON FRICTION STIR SPOT WELDING OF THERMOPLASTIC POLYMERS

    OpenAIRE

    Bekir ÇEVİK

    2014-01-01

    In this study, effect of bakelite interlayer powder on friction stir spot welding of polyethylene materials were investigated. 3 mm thick polyethylene materials were used in the experiments. 900 rpm rotational speed, 70, 100 and 130 seconds stirring time and 60 second waiting time were selected for the welding processes. Tensile-shear tests were applied on welded specimens and mechanical performances were determined

  13. Resistive Plate Chambers commissioning and performance results for 2015

    CERN Document Server

    CMS Collaboration

    2016-01-01

    The Resistive Plate Chamber (RPC) detector system at the Compact Muon Solenoid experiment at the LHC confers robustness and redundancy to the muon trigger. During the first long shutdown of the LHC (2013-2014) the CMS muon RPC system has been upgraded with 144 double-gap chambers on the forth forward stations. A total of 1056 double-gap chambers cover the pseudo-rapidity region up to 1.6. The main detector parameters are constantly and closely monitored to achieve operational stability and high quality data in the harsh conditions of the second run period of the LHC (13 TeV and 25 ns bunch spacing). Resistive Plate Chambers (RPC) performance results for 2015 with pp collisions at 13 TeV are presented. These results include the occupancy, efficiency of newly installed detectors after applying new working point, history plots for the RPC relevant variables such as: Cluster Size, Efficiency, percentage of inactive detector during operation and Rates and overall system noise. RPC variables are studied as funct...

  14. Fire resistance of a steel plate reinforced concrete bearing wall

    Energy Technology Data Exchange (ETDEWEB)

    Kodaira, Akio; Kanchi, Masaki; Fujinaka, Hideo [Takenaka Corporation, Tokyo (Japan); Akita, Shodo [Japan Atomic Power Co., Tokyo (Japan); Ozaki, Masahiko [The Kansai Electric Power Co., Osaka (Japan)

    2003-06-01

    Samples from a steel plate reinforced concrete bearing wall composed of concrete slab sandwiched between studded steel plates, were subjected to loaded fire resistance tests. There were two types of specimens: some were 1800 mm high while the rest were 3000 mm high ; thickness and width were the same for all specimens, at 200 mm and 800 mm, respectively. Under constant load conditions, one side of each specimen was heated along the standard fire-temperature curve. The results enabled us to approximate the relationship between the ratio of working load to concrete strength N/(Ac x c {sigma} b) and the fire resistance time (t: minutes), as equation (1) for the 1800 mm - high specimen, and equation (2) for the 3000 mm - high specimen. N/(Ac x c {sigma} b) = 2.21 x (1/t){sup 0.323} (1), .N/(Ac x c {sigma} b) 2.30 x (1/t){sup 0.378} (2) In addition, the temperature of the unheated side of the specimens was 100degC at 240 minutes of continuous heating, clearly indicating that there was sufficient heat insulation. (author)

  15. Fire resistance of a steel plate reinforced concrete bearing wall

    International Nuclear Information System (INIS)

    Samples from a steel plate reinforced concrete bearing wall composed of concrete slab sandwiched between studded steel plates, were subjected to loaded fire resistance tests. There were two types of specimens: some were 1800 mm high while the rest were 3000 mm high ; thickness and width were the same for all specimens, at 200 mm and 800 mm, respectively. Under constant load conditions, one side of each specimen was heated along the standard fire-temperature curve. The results enabled us to approximate the relationship between the ratio of working load to concrete strength N/(Ac x c σ b) and the fire resistance time (t: minutes), as equation (1) for the 1800 mm - high specimen, and equation (2) for the 3000 mm - high specimen. N/(Ac x c σ b) = 2.21 x (1/t)0.323 (1), .N/(Ac x c σ b) 2.30 x (1/t)0.378 (2) In addition, the temperature of the unheated side of the specimens was 100degC at 240 minutes of continuous heating, clearly indicating that there was sufficient heat insulation. (author)

  16. High-rate timing resistive plate chambers with ceramic electrodes

    Science.gov (United States)

    Laso Garcia, A.; Kotte, R.; Naumann, L.; Stach, D.; Wendisch, C.; Wüstenfeld, J.; Kämpfer, B.

    2016-05-01

    We describe recent advances in developing radiation-hard ceramic resistive plate chambers (CRPCs) with Si3N4/SiC composites. Bulk resistivity measurements for this material for different manufacturing processes are reported. The results show that the bulk resistivity ρ can vary between 107 and1013 Ω cm. The varistor type behaviour of the material is analysed. A comparison with other materials used in timing RPCs is given. We describe the assembly and tests of CRPC prototypes in electron and proton beams. For a prototype with ρ ~ 5 ×109 Ω cm, the efficiency of the detectors is 95% at a flux of 2 ×105cm-2s-1. The time resolution at the same flux is about 120 ps. A prototype with ρ ~ 2 ×1010 Ω cm shows an efficiency of about 85% up to fluxes of 5 ×104cm-2s-1 with a time resolution better than 80 ps. The results are compared with RPC models.

  17. A Computational Model of Soil Adhesion and Resistance for a Non-smooth Bulldozing Plate

    Institute of Scientific and Technical Information of China (English)

    Shi Wei-ping; Ren Lu-quan; Tian Li-mei

    2005-01-01

    Adhesive forces exist between soil and the surfaces of soil-engaging components; they increase working resistance and energy consumption. This paper tries to find an approach to reduce the adhesion and resistance of bulldozing plate. A simplified mechanical model of adhesion and resistance between soil and a non-smooth bulldozing plate is proposed. The interaction force between moist soil and a non-smooth bulldozing plate is analyzed. The pressure and friction distribution on the bulldozing plate are computed, and the anti-adhesive effect of a corrugated bulldozing plate is simulated numerically.Numerical results show that the wavy bulldozing plate achieves an effective drag reduction in moist soil. The optimal wavy shape of the corrugated bulldozing plate with the minimal resistance is designed. The basic principle of reducing soil adhesion of the non-smooth surface is discovered.

  18. Resistive Plate Chambers for 2013-2014 upgrade of CMS

    CERN Document Server

    Colafranceschi, Stefano

    2014-01-01

    The Compact Muon Solenoid (CMS) detector operates at the Large Hadron Collider (LHC) at CERN. It was proposed to install the fourth endcap (+,- RE4) consisting of Resistive Plate Chambers (RPCs) for the CMS muon Endcap system, in order to improve its Level-1 trigger efficiency and thereby completing the full implementation of the TDR, after which LHC will run with its full designed luminosity. This station is currently being installed in the first Long Shutdown (LS-1) of LHC during 2013-2014. In this presentation, we will discuss about the entire procedure of standardization of leak and spacer tests for the gas-gaps, the new design for the Cu cooling system, assembly, testing and characterization of RPCs which is being executed in a synchronized way at the three assembly sites at CERN, BARC-Mumbai and University of Ghent, Belgium. In this talk the RPC chamber production and commissioning will be described in detail. Few preliminary results will be shown.

  19. Resistive Plate Chambers for the Pierre Auger array upgrade

    International Nuclear Information System (INIS)

    In the framework of the Pierre Auger Observatory upgrade, Resistive Plate Chambers (RPCs) have been proposed as a dedicated detector to better estimate the muonic component of Extensive Air Showers (EAS), further constraining the nature of the cosmic rays and hadronic interactions that take place in Extensive Air Showers development. RPCs are a very interesting option to fulfill the requirements: to cover large areas at low cost; particle counting from one to thousands of particles; few ns time resolution and outdoor standalone operation with very low maintenance. The present work refers to the latest advances and outcomes in order to ensure the capability of RPCs to fulfill the totality of the Auger upgrade requirements

  20. Resistive Plate Chamber Digitization in a Hadronic Shower Environment

    CERN Document Server

    Deng, Z; Wang, Y; Yue, Q; Yang, Z; Apostolakis, J; Folger, G; Grefe, C; Ivantchenko, V; Ribon, A; Uzhinskiy, V; Boumediene, D; Carloganu, C; Français, V; Cho, G; Kim, D-W; Lee, S C; Park, W; Vallecorsa, S; Cauwenbergh, S; Tytgat, M; Pingault, A; Zaganidis, N; Brianne, E; Ebrahimi, A; Gadow, K; Göttlicher, P; Günter, C; Hartbrich, O; Hermberg, B; Irles, A; Krivan, F; Krüger, K; Kvasnicka, J; Lu, S; Lutz, B; Morgunov, V; Neubüser, C; Provenza, A; Reinecke, M; Sefkow, F; Schuwalow, S; Tran, H L; Garutti, E; Laurien, S; Matysek, M; Ramilli, M; Schroeder, S; Bilki, B; Norbeck, E; Northacker, D; Onel, Y; Chang, S; Khan, A; Kim, D H; Kong, D.J; Oh, Y D; Kawagoe, K; Hirai, H; Sudo, Y; Suehara, T; Sumida, H; Yoshioka, T; Gil, E Cortina; Mannai, S; Buridon, V; Combaret, C; Caponetto, L; Eté, R; Garillot, G; Grenier, G; Han, R; Ianigro, J C; Kieffer, R; Laktineh, I; Lumb, N; Mathez, H; Mirabito, L; Petrukhin, A; Steen, A; Antequera, J Berenguer; Alamillo, E Calvo; Fouz, M-C; Marin, J; Puerta-Pelayo, J; Verdugo, A; Chadeeva, M; Danilov, M; Gabriel, M; Goecke, P; Kiesling, C; vanderKolk, N; Simon, F; Szalay, M; Bilokin, S; Bonis, J; Cornebise, P; Richard, F; Pöschl, R; Rouëné, J; Thiebault, A; Zerwas, D; Anduze, M; Balagura, V; Belkadhi, K; Boudry, V; Brient, J-C; Cornat, R; Frotin, M; Gastaldi, F; Haddad, Y; Magniette, F; Ruan, M; Rubio-Roy, M; Shpak, K; Videau, H; Yu, D; Callier, S; di Lorenzo, S Conforti; Dulucq, F; Martin-Chassard, G; de la Taille, Ch; Raux, L; Seguin-Moreau, N; Kotera, K; Ono, H; Takeshita, T; Corriveau, F

    2016-01-01

    The CALICE Semi-Digital Hadron Calorimeter (SDHCAL) technological prototype is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a three-threshold readout as the active medium. This technology is one of the two options proposed for the hadron calorimeter of the International Large Detector for the International Linear Collider. The prototype was exposed to beams of muons, electrons and pions of different energies at the CERN Super Proton Synchrotron. To be able to study the performance of such a calorimeter in future experiments it is important to ensure reliable simulation of its response. In this paper we present our prototype simulation performed with GEANT4 and the digitization procedure achieved with an algorithm called SimDigital. A detailed description of this algorithm is given and the methods to determinate its parameters using muon tracks and electromagnetic showers are explained. The comparison with hadronic shower data shows a good agreement up to 50 GeV. Discrepancies are ...

  1. Gas mixture studies for streamer operated Resistive Plate Chambers

    Science.gov (United States)

    Paoloni, A.; Longhin, A.; Mengucci, A.; Pupilli, F.; Ventura, M.

    2016-06-01

    Resistive Plate Chambers operated in streamer mode are interesting detectors in neutrino and astro-particle physics applications (like OPERA and ARGO experiments). Such experiments are typically characterized by large area apparatuses with no stringent requirements on detector aging and rate capabilities. In this paper, results of cosmic ray tests performed on a RPC prototype using different gas mixtures are presented, the principal aim being the optimization of the TetraFluoroPropene concentration in Argon-based mixtures. The introduction of TetraFluoroPropene, besides its low Global Warming Power, is helpful because it simplifies safety requirements allowing to remove also isobutane from the mixture. Results obtained with mixtures containing SF6, CF4, CO2, N2 and He are also shown, presented both in terms of detectors properties (efficiency, multiple-streamer probability and time resolution) and in terms of streamer characteristics.

  2. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    International Nuclear Information System (INIS)

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  3. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: zuoy@mail.buct.edu.cn [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-01-15

    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  4. Efficiency Studies of the PHENIX Resistive Plate Chambers

    Science.gov (United States)

    Tate, Aric

    2012-10-01

    At Brookhaven National Laboratory the PHENIX experiment on the Relativistic Heavy Ion Collider (RHIC) studies polarized p+p collisions in an effort to better understand the contribution of sea quarks to the spin structure of the proton. To enable PHENIX to measure these contributions a trigger upgrade was needed to improve the ability of the data acquisition system to select single high transverse momentum muon events. A key component to the trigger upgrade was the addition of two stations of Resistive Plate Chambers (RPCs) in each muon arm. These chambers were installed and fully implemented prior to the last RHIC run. To ensure that the RPCs will continue to perform efficiently many tests have been done, both on the installed chambers and spare chambers on a cosmic test stand. An efficiency versus high voltage test was run with the cosmic stand as well as an efficiency versus threshold test to try and maximize efficiency without gaining noise. A noise versus threshold scan helped determine at what threshold the RPCs best perform. These tests help us to operate the RPCs at a high efficiency and low noise manner. The analysis and results of these tests will be presented.

  5. Resistive Plate Chamber digitization in a hadronic shower environment

    Science.gov (United States)

    Deng, Z.; Li, Y.; Wang, Y.; Yue, Q.; Yang, Z.; Boumediene, D.; Carloganu, C.; Français, V.; Cho, G.; Kim, D.-W.; Lee, S. C.; Park, W.; Vallecorsa, S.; Apostolakis, J.; Folger, G.; Grefe, C.; Ivantchenko, V.; Ribon, A.; Uzhinskiy, V.; Cauwenbergh, S.; Tytgat, M.; Pingault, A.; Zaganidis, N.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Neubüser, C.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H. L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schroeder, S.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Chang, S.; Khan, A.; Kim, D. H.; Kong, D. J.; Oh, Y. D.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Yoshioka, T.; Cortina Gil, E.; Mannai, S.; Buridon, V.; Combaret, C.; Caponetto, L.; Eté, R.; Garillot, G.; Grenier, G.; Han, R.; Ianigro, J. C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Berenguer Antequera, J.; Calvo Alamillo, E.; Fouz, M.-C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Chadeeva, M.; Danilov, M.; Corriveau, F.; Gabriel, M.; Goecke, P.; Kiesling, C.; van der Kolk, N.; Simon, F.; Szalay, M.; Bilokin, S.; Bonis, J.; Cornebise, P.; Richard, F.; Pöschl, R.; Rouëné, J.; Thiebault, A.; Zerwas, D.; Anduze, M.; Balagura, V.; Belkadhi, K.; Boudry, V.; Brient, J.-C.; Cornat, R.; Frotin, M.; Gastaldi, F.; Haddad, Y.; Magniette, F.; Ruan, M.; Rubio-Roy, M.; Shpak, K.; Videau, H.; Yu, D.; Callier, S.; Conforti di Lorenzo, S.; Dulucq, F.; Martin-Chassard, G.; de la Taille, Ch.; Raux, L.; Seguin-Moreau, N.; Kotera, K.; Ono, H.; Takeshita, T.

    2016-06-01

    The CALICE Semi-Digital Hadronic Calorimeter technological prototype is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a three-threshold readout as the active medium. This technology is one of the two options proposed for the hadronic calorimeter of the International Large Detector for the International Linear Collider. The prototype was exposed to beams of muons, electrons and pions of different energies at the CERN Super Proton Synchrotron. To be able to study the performance of such a calorimeter in future experiments it is important to ensure reliable simulation of its response. This paper presents the SDHCAL prototype simulation performed with GEANT4 and the digitization procedure achieved with an algorithm called SimDigital. A detailed description of this algorithm is given and the methods to determinate its parameters using muon tracks and electromagnetic showers are explained. The comparison with hadronic shower data shows a good agreement up to 50 GeV. Discrepancies are observed at higher energies. The reasons for these differences are investigated.

  6. Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jensen Lars

    2008-09-01

    Full Text Available Abstract Background Screening and enumeration of antimicrobial resistant Escherichia coli directly from samples is needed to identify emerging resistant clones and obtain quantitative data for risk assessment. Aim of this study was to evaluate the performance of 3M™ Petrifilm™ Select E. coli Count Plate (SEC plate supplemented with antimicrobials to discriminate antimicrobial-resistant and non-resistant E. coli. Method A range of E. coli isolates were tested by agar dilution method comparing the Minimal Inhibitory Concentration (MIC for eight antimicrobials obtained by Mueller-Hinton II agar, MacConkey agar and SEC plates. Kappa statistics was used to assess the levels of agreement when classifying strains as resistant, intermediate or susceptible. Results SEC plate showed that 74% of all strains agreed within ± 1 log2 dilution when comparing MICs with Mueller-Hinton II media. High agreement levels were found for gentamicin, ampicillin, chloramphenicol and cefotaxime, resulting in a kappa value of 0.9 and 100% agreement within ± 1 log2 dilution. Significant variances were observed for oxytetracycline and sulphamethoxazole. Further tests showed that the observed discrepancy in classification of susceptibility to oxytetracycline by the two media could be overcome when a plate-dependent breakpoint of 64 mg/L was used for SEC plates. For sulphamethoxazole, SEC plates provided unacceptably high MICs. Conclusion SEC plates showed good agreement with Mueller-Hinton II agar in MIC studies and can be used to screen and discriminate resistant E. coli for ampicillin, cephalothin, streptomycin, chloramphenicol, cefotaxime and gentamicin using CLSI standardized breakpoints, but not for sulphamethoxazole. SEC plates can also be used to discriminate oxytetracycline-resistant E. coli if a plate-dependent breakpoint value of 64 mg/L is used.

  7. Antibiotic resistance in triclosan heterotrophic plate count bacteria from sewage water / Ilsé Coetzee

    OpenAIRE

    Coetzee, Ilsé

    2015-01-01

    The concentration of triclosan in antiseptics, disinfectants and preservatives in products exceeds the minimal lethal levels. Extensive use of triclosan and antibiotics results in bacterial resistance to their active ingredients. The precise relationship between use and resistance, however, has been challenging to define. The aim of the study was to identify and determine antibiotic resistance profiles of triclosan tolerant heterotrophic plate count bacteria isolates from sewag...

  8. An electroless plating film of palladium on 304 stainless steel and its excellent corrosion resistance

    International Nuclear Information System (INIS)

    An uniform palladium film on 304 stainless steel was obtained by electroless plating. Scanning electronic microscopy, X-ray photoelectron spectroscopy, weight loss tests and electrochemical measurements were used to character the properties of the film. The palladium plated stainless steel samples showed excellent corrosion resistance in strong reductive corrosion mediums. In boiling dilute sulfuric acid solutions and boiling acetic/formic acids, corrosion rates of palladium plated 304 stainless steel samples were 3 or 4 orders of magnitude lower than the original 304 stainless steel samples. In solutions with NaCl concentration less that 0.1%, the palladium plated samples also showed better corrosion resistance. The function of palladium film on stainless steel is to raise the electrode potential and promote passivation of the steel in strong corrosive environments

  9. Solution of two-dimensional flow in partially blocked parallel plates using electrical resistive network method

    International Nuclear Information System (INIS)

    Two-dimensional flow in partially blocked parallel plates with partially intact fuel rods is treated using the electrical resistive network method. The dimensions of the plate are approximately equivalent to those at the Clinch River Breeder Reactor fuel subassembly. In the analysis, expansion and contraction losses are found to be negligible. The Burke-Plummer equation is used for both axial and across-the-plate flows for the blockage region. The results show that the penetrating flow through the blockage is substantially larger than that given by one-dimensional cylindrical geometry analysis. (orig.)

  10. Study of electrostatic potential in the GAMMA 10 end region with variation of end plate resistance

    Energy Technology Data Exchange (ETDEWEB)

    Tatematsu, Yoshinori; Saito, Teruo; Imaizumi, Yusuke; Nishida, Keiichi; Yokoyama, Eiji; Ishikawa, Masao; Katanuma, Isao; Tatsu, Kiyoshi [Tsukuba Univ., Plasma Research Center, Tsukuba, Ibaraki (Japan); Kajiwara, Ken [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-07-01

    An experiment of variation of an end plate resistance over several orders of magnitude is carried out in GAMMA 10. The axial potential distribution in the end region is measured for a wide range of an end plate net current. A potential model which calculates a potential distribution in front of a current carrying wall is developed. The potential depth from a mirror throat (B=3 T) to the end plate (B=0.01 T) is calculated with this model. The experimental results are well explained by this model. (author)

  11. Response of a resistive plate chamber to particles leaking laterally from a thick absorber

    International Nuclear Information System (INIS)

    Resistive plate chamber detectors, working in streamer mode, have been chosen to equip the ALICE/LHC dimuon trigger. In ALICE, the detector will be placed orthogonal to a thick beam shield. Tests of the detector have been performed in order to investigate its performances in such running conditions. These tests show that resistive plate chambers can be operated in streamer mode in these particular conditions without dramatic deterioration of the overall performances. FLUKA simulations reproduce the experimental results within a factor 1.5. Such a test is not only relevant for the ALICE dimuon trigger but for all collider experiments using the RPC detector

  12. Position information by signal analysis in real time from resistive anode microchannel plate detector

    Science.gov (United States)

    Saha, K.; Benmaimon, R.; Prabhakaran, A.; Rappaport, M. L.; Heber, O.; Schwalm, D.; Zajfman, D.

    2016-07-01

    Resistive anode multichannel plate detectors are extensively used for imaging photons, electrons and ions. We present a method to acquire position information from such detector systems by considering simple parameters of the signals produced from the resistive anode encoder. Our technique is easy to implement and computes position in real time during experiments. Position information can be obtained using our method without the need for dedicated position analyser units.

  13. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    Science.gov (United States)

    Wang, Hongyu; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-11-01

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2-12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below -10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI.

  14. Corrosion resistance of Mg-Mn-Ce magnesium alloy modified by polymer plating

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Polymeric nano-film on the surface of Mg-Mn-Ce magnesium alloy was fabricated by polymer plating of 6-dihexylamino-1,3,5-triazine-2,4-dithiol monosodium(DHN)to improve its corrosion resistance.The electrochemical reaction process was analyzed by cyclic voltammetry and two obvious peaks of oxidation reaction were observed.The static contact angle of distilled water on polymer-plated surface can be up to 106.3°while on the blank surface it is 45.8°.Potentiodynamic polarization results show that the polymeric film Can increase the corrosion potential from-1.594 V VS SCE for blank to-0.382 V VS SCE.The results of electrochemical impedance spectroscopy indicate that the charge transfer resistances of blank and polymer-plated fabricating hydrophobic film on Mg-Mn-Ce alloy surface and improving its anti-corrosion property.

  15. Properties of a six-gap timing resistive plate chamber with strip readout

    International Nuclear Information System (INIS)

    Six-gap glass timing resistive plate chamber with strip readout was tested using IHEP U-70 PS test beam. The time resolution of ∼ 45 ps at efficiency larger than 98% was achieved. Position resolution along strip was estimated to be ∼1 cm

  16. The properties of glass resistive plate chambers made of different glasses

    International Nuclear Information System (INIS)

    Glass resistive plate chambers (GRPCs) have been proposed as the basic element for the JUNO top tracker detector. With good uniform performance and low cost, GRPCs are well suited for large area experiments. Glass RPCs used in underground experiments require specially designed cassette and gas flow systems, since the glass is fragile and easily corroded by acid generated by water entering the gas-filled chamber. High-strength and chemical-resistant glasses have been proposed for underground experiments. We present here the test results of four GRPC chambers made of different glasses: normal thin glass, two high-strength glasses, and a chemical-resistant glass. The chemical-resistant and high-strength glasses have good surface quality, but their volume resistivities are higher. Higher resistivities lead to a higher required voltage to reach plateau operation, meaning that these glasses can only work in a very low rate experiment

  17. Electron beam lithography of Fresnel zone plates using a rectilinear machine and trilayer resists

    International Nuclear Information System (INIS)

    We describe the use of a commercial e-beam lithography system (JEOL JBX-6000FS) to fabricate Fresnel zone plates for x-ray microscopy. The machine is capable of controlling the pitch of optical gratings with sub-nanometer precision, so its beam placement properties are more than adequate for zone plate fabrication. The zone plate pattern is written into a thin top layer (PMMA or Calixarene) of a trilayer resist, and transferred into thick nickel zones using reactive ion etching (RIE) followed by electroplating. Zone plates with outermost zone widths of 30 nm have exhibited efficiencies up to 10.0% at a 390 eV photon energy and with diameters in the range 80 to 120 μm. Zone plates with outer zones of 18 to 20 nm were also fabricated in thinner Ni with correspondingly lower efficiencies of 2.6%. Zone plates with outermost zone widths of 45 nm have been fabricated with larger diameters up to 160 μm. All results reported were obtained with a 50 kV system with 80 μm field deflection size; future efforts will make use of a 100 kV, 500 μm field size system

  18. Cavitation-erosion resistance of arc ion-plated (Ti, Cr) N coatings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The cavitation-erosion behavior of (Ti,Cr)N multi-component coatings produced by arcion-plating on grey cast iron was studied by using an ultrasonic cavitation -erosion testing appara-tus and scanning electron microscopy. The test results indicated that surface roughness of thesubstrate, surface morphology of the coating, substrate bias voltage and the thickness of the coat-ing had certain influence on the erosion rate. Arc ion-plated (Ti,Cr)N multi-component coatingsshowed better cavitation -erosion resistance than single component coatings because of highermicrohardness and good adhesion.

  19. On Free Vibrations of Orthotropic Plates in the Presence of Viscous Resistance

    Directory of Open Access Journals (Sweden)

    Aghalovyan L.A.

    2011-03-01

    Full Text Available The three-dimensional problem of elasticity theory of the free vibrations of orthotropic plates in the presence of viscous resistance, on the facial plane of which mixed-boundary conditions of elasticity theory are given is considered. By the asymptotic method it is shown that 3 groups of free vibrations, 2 groups of shearing and 1 group of longitudinal free vibrations are appeared. The stress-deformed states, principal values of frequencies and the forms of natural vibrations of plates relevant to 3 groups of free vibrations are determined.

  20. Fracture toughness and crack growth resistance of pressure vessel plate and weld metal steels

    International Nuclear Information System (INIS)

    Compact tension specimens were used to measure the initiation fracture toughness and crack growth resistance of pressure vessel steel plates and submerged arc weld metal. Plate test specimens were manufactured from four different casts of steel comprising: aluminium killed C-Mn-Mo-Cu and C-Mn steel and two silicon killed C-Mn steels. Unionmelt No. 2 weld metal test specimens were extracted from welds of double V butt geometry having either the C-Mn-Mo-Cu steel (three weld joints) or one particular silicon killed C-Mn steel (two weld joints) as parent plate. A multiple specimen test technique was used to obtain crack growth data which were analysed by simple linear regression to determine the crack growth resistance lines and to derive the initiation fracture toughness values for each test temperature. These regression lines were highly scattered with respect to temperature and it was very difficult to determine precisely the temperature dependence of the initiation fracture toughness and crack growth resistance. The data were re-analysed, using a multiple linear regression method, to obtain a relationship between the materials' crack growth resistance and toughness, and the principal independent variables (temperature, crack growth, weld joint code and strain ageing). (author)

  1. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature of......Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through the...

  2. Effects of gold plating on the resistance to high temperature discoloration of the cavity for ceramic packages

    Institute of Scientific and Technical Information of China (English)

    Zhanhua Wang; Zhuoshen Shen; Daobin Mu

    2004-01-01

    The effects of thickness and types of gold plating on the resistance to high temperature discoloration of gold plating on cavity surface of ceramic package were investigated. It was found that the thicker gold plating, the less discoloration degree for ceramic packages. Non-cyanide gold plating performed better resistance to high-temperature aging than cyanide gold plating. The relationship between the gold plating thickness and the amount of diffused Ni to the gold plating of ceramic packages with Au/Ni and Au/Ni-Co platings after heating at 420℃ for 15 min was also studied. When the gold plating thickness reach 2.0 μm and 1.6 μm for Au/Ni and Au/Ni-Co plating systems, respectively, no discoloration was observed on the gold plating surface of cavity, and the corresponding diffused Ni amounts (mass fraction) are 1.0% and 0.4%, while the diffused Co to the gold plating is 0.04%.

  3. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    International Nuclear Information System (INIS)

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2–12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below −10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI. - Highlights: • The Co-coated carbonyl iron Co(CI) particles were prepared by electroless plating. • The electromagnetic wave absorbing properties of Co(CI) particles were studied. • The heat treatment on the absorbing property of Co(CI) particles was studied. • The Co(CI) particles have good absorbing property when compared with CI

  4. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongyu, E-mail: wanghongyu07010310@163.com; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-11-01

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2–12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below −10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI. - Highlights: • The Co-coated carbonyl iron Co(CI) particles were prepared by electroless plating. • The electromagnetic wave absorbing properties of Co(CI) particles were studied. • The heat treatment on the absorbing property of Co(CI) particles was studied. • The Co(CI) particles have good absorbing property when compared with CI.

  5. FLOW RESISTANCE AND HEAT TRANSFER CHARACTERISTICS OF A NEW-TYPE PLATE HEAT EXCHANGER

    Institute of Scientific and Technical Information of China (English)

    LUAN Zhi-jian; ZHANG Guan-min; TIAN Mao-cheng; FAN Ming-xiu

    2008-01-01

    A new-type corrugation Plate Heat Exchanger (PHE) was designed. Results from both numerical simulations and experiments showed that the flow resistance of the working fluid in this new corrugation PHE, compared with the traditional chevron-type one, was decreased by more than 50%, and corresponding heat transfer performance was decreased by about 25%. The flow field of the working fluid in the corrugation PHE was transformed and hence performance difference in both flow resistance and heat transfer was generated. Such a novel plate, consisting of longitudinal and transverse corrugations, can effectively avoid the problem of flow path blockage, which will help to extend the application of PHEs to the situation with unclean working fluids.

  6. In-beam evaluation of a medium-size Resistive-Plate WELL gaseous particle detector

    CERN Document Server

    Moleri, L; Arazi, L; Azevedo, C D R; Breskin, A; Coimbra, A E C; Oliveri, E; Pereira, F A; Renous, D Shaked; Schaarschmidt, J; Santos, J M F dos; Veloso, J F C A; Bressler, S

    2016-01-01

    In-beam evaluation of a fully-equipped medium-size 30$\\times$30 cm$^2$ Resistive Plate WELL (RPWELL) detector is presented. It consists here of a single element gas-avalanche multiplier with Semitron ESD225 resistive plate, 1 cm$^2$ readout pads and APV25/SRS electronics. Similarly to previous results with small detector prototypes, stable operation at high detection efficiency (>98%) and low average pad multiplicity (~1.2) were recorded with 150 GeV muon and high-rate pion beams, in Ne/(5%CH$_4$), Ar/(5%CH$_4$) and Ar/(7%CO$_2$). This is an important step towards the realization of robust detectors suitable for applications requiring large-area coverage; among them Digital Hadron Calorimetry.

  7. Electroless Plating of Ni-Fe-P Alloy and Corrosion Resistance of the Deposit

    Institute of Scientific and Technical Information of China (English)

    Senlin WANG

    2005-01-01

    Electroless Ni-Fe-P alloys in an alkaline bath were plated. Theeffects of deposition parameters on the plating rate and the coating composition were examined. The weight loss test and the anodic polarization measurement of the deposits in 3.5 wt pct NaCl solution (pH7.0) showed that the deposits with the mole ratio of NiSO4/FeSO4 being 0.07:0.03, pH8.0 and 7.5 possess better corrosion resistance than that of the other deposits and the Ni-Fe-P deposits did not form passive films in this environment. In 5.0 wt pct NaOH solution, the Ni-Fe-P deposits have better corrosion resistance and formed passive films.

  8. Thermal fatigue resistance of W-Cu divertor plates for fusion reactors

    International Nuclear Information System (INIS)

    The results of thermal cycling tests of W-Cu pseudo-alloy as a candidate material for fusion reactor divertor plates showed that the material resisted without any damages to radiation and thermal shock effects of cyclic electron beam of 6, 8 and 10 MW/m2 power density when a good thermal sink was provided. Practically ideal thermal contact between thermally loaded sample and cooled substrate was shown can be obtained using various spelters vacuum brazing. 2 refs.; 4 figs

  9. Efficiency determination of resistive plate chambers for fast quasi-monoenergetic neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Roeder, M.; Cowan, T.E.; Kempe, M.; Yakorev, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universitaet Dresden, Dresden (Germany); Elekes, Z. [MTA ATOMKI, Debrecen (Hungary); Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Aumann, T.; Caesar, C. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt, Darmstadt (Germany); Bemmerer, D.; Sobiella, M.; Stach, D.; Wagner, A. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Boretzky, K.; Hehner, J.; Heil, M. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Maroussov, V. [Universitaet zu Koeln, Koeln (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Nusair, O. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Al-Balqa Applied University, Salt (Jordan); Prokofiev, A.V. [Uppsala University, The Svedberg Laboratory, Uppsala (Sweden); Reifarth, R. [Johann Wolfgang Goethe - Universitaet, Frankfurt am Main (Germany); Zilges, A. [Universitaet zu Koeln, Koeln (Germany); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany); Collaboration: R3B Collaboration

    2014-07-15

    Composite detectors made of stainless-steel converters and multigap resistive plate chambers have been irradiated with quasi-monoenergetic neutrons with a peak energy of 175 MeV. The neutron detection efficiency has been determined using two different methods. The data are in agreement with the output of Monte Carlo simulations. The simulations are then extended to study the response of a hypothetical array made of these detectors to energetic neutrons from a radioactive ion beam experiment. (orig.)

  10. Performance Study of the CMS Barrel Resistive Plate Chambers with Cosmic Rays

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; 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Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; 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Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    In October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of 90%. In this paper, the performance of the detector during these dedicated runs is reported.

  11. Performance test of the Multi-gap Resistive Plate Chamber (MRPC) with cosmic ray

    Science.gov (United States)

    Ikeda, Michihiko; Akieda, Tomomi; Tomita, Shoko; Ninomiya, Aki

    2014-09-01

    MRPC is a gaseous ionization detector, which a good timing resolution has been used practically in the nuclear and particle physics experiment. A mixed gas of SF6 and Fleon 134a was flowed through the gaps between high resistive plates (500 μm thickness glass). A high electric field of ~2 ×106 [V/m] was applied between the plates. A charged particle passes through the MRPC and causes avalanche amplification. We constructed a relatively small MRPC with a readout pad (20 mm × 50 mm). The development is motivated by feasibility study of the MRPC as a photon tagger at the Research Center for Electron Photon Science (ELPH), Tohoku University. The photon tagger needs a good timing resolution (Tohoku University as an example of nuclear experimental detectors. We will measure the zenith angle and velocity distributions of cosmic ray.

  12. Optimizing the position resolution of a Z-stack microchannel plate resistive anode detector for low intensity signals

    International Nuclear Information System (INIS)

    A method for achieving good position resolution of low-intensity electron signals using a microchannel plate resistive anode detector is demonstrated. Electron events at a rate of 7 counts s−1 are detected using a Z-stack microchannel plate. The dependence of position resolution on both the distance and the potential difference between the microchannel plate and resistive anode is investigated. Using standard commercial electronics, a measured position resolution of 170 μm (FWHM) is obtained, which corresponds to an intrinsic resolution of 157 μm (FWHM)

  13. Effect of manufacturing process sequence on the corrosion resistance characteristics of coated metallic bipolar plates

    Science.gov (United States)

    Dur, Ender; Cora, Ömer Necati; Koç, Muammer

    2014-01-01

    Metallic bipolar plate (BPP) with high corrosion and low contact resistance, durability, strength, low cost, volume, and weight requirements is one of the critical parts of the PEMFC. This study is dedicated to understand the effect of the process sequence (manufacturing then coating vs. coating then manufacturing) on the corrosion resistance of coated metallic bipolar plates. To this goal, three different PVD coatings (titanium nitride (TiN), chromium nitride (CrN), zirconium nitride (ZrN)), with three thicknesses, (0.1, 0.5, 1 μm) were applied on BPPs made of 316L stainless steel alloy before and after two types of manufacturing (i.e., stamping or hydroforming). Corrosion test results indicated that ZrN coating exhibited the best corrosion protection while the performance of TiN coating was the lowest among the tested coatings and thicknesses. For most of the cases tested, in which coating was applied before manufacturing, occurrence of corrosion was found to be more profound than the case where coating was applied after manufacturing. Increasing the coating thickness was found to improve the corrosion resistance. It was also revealed that hydroformed BPPs performed slightly better than stamped BPPs in terms of the corrosion behavior.

  14. Experimental and Numerical Investigation on the Ballistic Resistance of Double-Layered Steel Plates

    Science.gov (United States)

    Xiao, Xinke; Zhang, Wei; Guo, Zitao; Wei, Gang

    2011-06-01

    The ballistic perforation resistance of double-layered steel plates impacted by flat-nosed projectiles was investigated both experimentally and numerically. In the tests, 10 mm thick (intact or spaced by 200 mm gap space) targets of Q235A steel were impacted using a gas-gun at sub-ordnance velocity, and the ballistic limit velocity of the different target configurations was obtained. The Johnson-Cook strength and fracture models were used in the finite element simulations, where the model constants were calibrated by preliminary material tests and taken from open literature. In general, good agreement was obtained between the numerical simulations and the experimental results. It was found that the ballistic resistance of spaced targets suffers from large divergence due to the projectile's different residual attitude after perforation of the front plate, and that it seems the initial-residual velocity data yield to two groups and therefore give birth to two ballistic limit velocities. However, the overall ballistic resistance of the spaced targets is less than that of the in contact ones.

  15. Comparison of CMS Resistive Plate Chambers performance during LHC RUN-1 and RUN-2

    CERN Document Server

    Shah, Mehar Ali

    2016-01-01

    The Resistive Plate Chambers detector system at the CMS experiment at the LHC provides robustness and redundancy to the muon trigger. A total of 1056 double-gap chambers cover the pseudo-rapidity region < 1.6. The main detector parameters and environmental conditions are constantly and closely monitored to achieve operational stability and high quality data in the harsh conditions of the second run period of the LHC with center-of-mass energy of 13 TeV. First results of overall detector stability with 2015 data and comparisons with data from the LHC RUN-1 period at 8 TeV are presented.

  16. Comparison of CMS Resistive Plate Chambers performance during LHC RUN-1 and RUN-2

    CERN Document Server

    Shah, Mehar Ali

    2016-01-01

    The Resistive Plate Chambers detector system at the CMS experiment at the LHC provides robustness and redundancy to the muon trigger. A total of 1056 double-gap chambers cover the pseudo-rapidity region lt 1.6. The main detector parameters and environmental conditions are constantly and closely monitored to achieve operational stability and high quality data in the harsh conditions of the second run period of the LHC with center-of-mass energy of 13 TeV. First results of overall detector stability with 2015 data and comparisons with data from the LHC RUN-1 period at 8 TeV are presented.

  17. GEANT4 simulation of gamma ray in a double-gap resistive plate chamber

    Institute of Scientific and Technical Information of China (English)

    J. T. Rhee; M. Jamil; Steve Hall; Y. J. Jeon

    2006-01-01

    For more than 20 years nuclear physicists have used the GEANT code to simulate particle-matter interaction. In most recent version, GEANT4 is a toolkit for simulating the passage of particles though matter, which contains a complete range of functionality including tracking, geometry, physics models, and hits. In this article, an attempt to use GEANT4 to model a double-gap resistive plate chamber (RFC) with its improved efficiency is presented. The efficiencies of the double-gap RFC have been evaluated as a function of gamma energy range 0.005-1OOOMeV. A comparison to available previous simulation package GEANT3 data is also performed.

  18. Study of the effect of water vapor on a resistive plate chamber with glass electrodes

    CERN Document Server

    Sakai, H H; Teramoto, Y; Nakano, E E; Takahashi, T T

    2002-01-01

    We studied the effects of water vapor on the efficiencies of resistive plate chambers with glass electrodes, operated in the streamer mode. With moisture in the chamber gas that has freon as a component (water vapor approx 1000 ppm), a decrease in the efficiency (approx 20%) has been observed after operating for a period of several weeks to a few months. From our study, the cause of the efficiency decrease was identified as a change on the cathode surface. In addition, a recovery method was found: flushing for 1 day with argon bubbled through water containing >=3% ammonia, followed by a few weeks of training with dry gas.

  19. A large-area glass-resistive plate chamber with multistrip readout

    International Nuclear Information System (INIS)

    A completely new configuration of a glass resistive-plate chamber (GRPC) was built and tested. It consists of a double two-gap structure of electrodes with an active area of about 400 cm2 and is read out via a central multistrip printed circuit board. In measurements with a 60Co source and p, d particles of 1.5 A GeV time resolutions better than 80 ps, position resolution along the strips of 5-6 mm and efficiencies larger than 95% were obtained using available fast standard electronics. These results open the possibility of constructing compact TOF detectors of high resolution and high granularity

  20. Wear and Corrosion Resistance of Electroless Plating Ni-P Coating on P110 Steel

    Institute of Scientific and Technical Information of China (English)

    LIN Naiming; ZHOU Peng; ZOU Jiaojuan; XIE Faqin; TANG Bin

    2015-01-01

    In order to improve the surface performance and increase the lifetime of P110 oil casing tube steel during operation, electroless plating was conducted to form Ni-P coating onto its surface. The surface morphology/element distribution and phase constitution of the Ni-P coating were analyzed using scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). Tribological and electrochemical measurement tests were applied to investigate the wear and corrosion resistance of P110 steel and the Ni-P coating. The results showed that a uniform and compact, high phosphorous Ni-P coating was formed. The obtained Ni-P coating indicated certain friction-reduction effect and lower mass loss during friction-wear tests. The Ni-P coating also exhibited higher corrosion resistance in comparison with bared P110 steel. The obtained Ni-P coating has signifi cantly improved the surface performance of P110 steel.

  1. Simulation of space charge effect on time resolution in resistive plate chambers

    International Nuclear Information System (INIS)

    India Based Neutrino Observatory (INO) will use 28,800 Resistive Plate Chambers (RPCs) in its 50 kton magnetized Iron Calorimeter (ICAL). RPCs are gaseous parallel-plate detectors that contain a small gas gap between two parallel plates which are kept under a high voltage of a few kVs. The main features of this detector are excellent spatial resolution and time resolution. These detectors have been successfully used in many particle physics experiments and are well suited for fast space-time particle tracking as required for the muon trigger at the LHC experiments. The RPC can be operated either in the streamer or in the avalanche mode. In order to study the signal generation from the RPC, space charge effect is an important phenomenon to be considered. We have compared the simulated time resolution with the measured time resolution in the avalanche mode for different gas mixtures in our previous work, without considering the space charge effect. If the number of charge carriers in the avalanche reaches large values they influence the electric field and the gas gain in the gap. This phenomenon is called space charge effect. In this paper, we take into account the space charge effect to calculate time resolution

  2. The Resistive-Plate WELL with Argon mixtures - a robust gaseous radiation detector

    CERN Document Server

    Moleri, L; Arazi, L; Azevedo, C D R; Oliveri, E; Pitt, M; Schaarschmidt, J; Shaked-Renous, D; Santos, J M F dos; Veloso, J F C A; Breskin, A; Bressler, S

    2016-01-01

    A thin single-element THGEM-based, Resistive-Plate WELL (RPWELL) detector was operated with 150 GeV/c muon and pion beams in Ne/(5%CH$_4$), Ar/(5%CH$_4$) and Ar/(7%CO$_2$); signals were recorded with 1 cm$^2$ square pads and SRS/APV25 electronics. Detection efficiency values greater than 98% were reached in all the gas mixtures, at average pad multiplicity of 1.2. The use of the 10$^9${\\Omega}cm resistive plate resulted in a completely discharge-free operation also in intense pion beams. The efficiency remained essentially constant at 98-99% up to fluxes of $\\sim$10$^4$Hz/cm$^2$, dropping by a few % when approaching 10$^5$ Hz/cm$^2$. These results pave the way towards cost-effective, robust, efficient, large-scale detectors for a variety of applications in future particle, astro-particle and applied fields. A potential target application is digital hadron calorimetry.

  3. The influence of heat treatment on microstructure and crack resistance of boron microalloyed steel plates

    Directory of Open Access Journals (Sweden)

    M. Opiela

    2010-11-01

    Full Text Available crack resistance of C-Mn constructional steels with microaddition of boron assigned to be used in production of high strength steel plates.Design/methodology/approach: Metallographic observations, heat treatment, hardness measurements, impact strength examinations, fractographic analyses of fracture surfaces of test pieces have been performed.Findings: Dispersive particles of interstitial phases formed on dislocations during the plastic deformation, limiting grain growth of austenite, create the possibility to obtain metallurgical products with fine-grained microstructure giving them high strength and guaranteed crack resistance, also at low temperature.Research limitations/implications: Further research of microstructure in transmission electron microscope as well as complementary impact resistance tests at the temperature lower than -60°C are foreseen to be performed.Practical implications: Obtained results of examinations, especially detailed fractographic analysis of fracture surfaces of test pieces together with chemical composition analysis of revealed non-metallic inclusions and precipitations of secondary phases will make contribution to better understanding of cracking mechanisms in the group of high-strength steels.Originality/value: Performed research revealed that investigated steels present high crack resistance also at low temperature. It can be achieved through proper selection of chemical composition and adequate conditions of heat treatment and plastic working. The presence of microadditions of transition metals deriving from IVb and Vb group of periodic classification of the elements with high chemical affinity to nitrogen and carbon allows producing rolled products with high exploitation properties.

  4. Study on corrosion resistance of palladium films on 316L stainless steel by electroplating and electroless plating

    International Nuclear Information System (INIS)

    Palladium films with good adhesive strength were deposited on 316L stainless steel by electroless plating and electroplating. Scanning electronic microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, weight loss tests and electrochemical methods were used to study the properties of the films. The electroless plated palladium film mainly consisted of palladium, phosphorus and nitrogen, and the electroplated palladium film was almost pure palladium. XPS analysis indicated that palladium was present in the films as metal state. The palladium plated stainless steel samples prepared by both methods showed excellent corrosion resistance in strong reductive corrosion mediums. In boiling 20% dilute sulfuric acid solution, the corrosion rates of the palladium plated 316L stainless steel samples were four orders of magnitude lower than that of the original 316L stainless steel samples. In the solution with 0.01 M NaCl, the palladium plated samples also showed better corrosion resistance. In comparison, the electroplated samples showed slightly better corrosion resistance than electroless plated samples, which may be attributed to less impurities and thereby higher corrosion potential for the former

  5. First in-beam studies of a Resistive-Plate WELL gaseous multiplier

    CERN Document Server

    Bressler, S; Pitt, M; Kudella, S; Azevedo, C D R; Amaro, F D; Jorge, M R; dos Santos, J M F; Veloso, J F C A; Natal da Luz, H; Arazi, L; Olivieri, E; Breskin, A

    2016-01-01

    We present the results of the first in-beam studies of a medium size (10$\\times$10 cm$^2$) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity ($\\sim$10$^9 \\Omega$cm). The 6.2~mm thick (excluding readout electronics) single-stage detector was studied with 150~GeV muons and pions. Signals were recorded from 1$\\times$1 cm$^2$ square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne\\(5% $\\mathrm{CH_{4}}$) at a gas gain of a few times 10$^4$, reaching 99$\\%$ detection efficiency at average pad multiplicity of $\\sim$1.2. Operation at particle fluxes up to $\\sim$10$^4$ Hz/cm$^2$ resulted in $\\sim$23$\\%$ gain drop leading to $\\sim$5$\\%$ efficiency loss. The striking feature was the discharge-free operation, also in intense pion beams. These results pave the way towards robust, efficient large-scale detectors for applications requiring economic solutions at moderate spatial and energy resolutions.

  6. First in-beam studies of a Resistive-Plate WELL gaseous multiplier

    Science.gov (United States)

    Bressler, S.; Moleri, L.; Pitt, M.; Kudella, S.; Azevedo, C. D. R.; Amaro, F. D.; Jorge, M. R.; dos Santos, J. M. F.; Veloso, J. F. C. A.; Natal da Luz, H.; Arazi, L.; Olivieri, E.; Breskin, A.

    2016-01-01

    We present the results of the first in-beam studies of a medium size (10 × 10 cm 2 ) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity (∼109 Ωcm). The 6.2 mm thick (excluding readout electronics) single-stage detector was studied with 150 GeV muons and pions. Signals were recorded from 1×1 cm 2 square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne/(5%CH4) at a gas gain of a few times 104 , reaching 99% detection efficiency at average pad multiplicity of ∼1.2. Operation at particle fluxes up to ∼104 Hz/cm 2 resulted in ∼23% gain drop leading to ∼5% efficiency loss. The striking feature was the discharge-free operation, also in intense pion beams. These results pave the way towards robust, efficient large-scale detectors for applications requiring economic solutions at moderate spatial and energy resolutions.

  7. First in-beam studies of a Resistive-Plate WELL gaseous multiplier

    International Nuclear Information System (INIS)

    We present the results of the first in-beam studies of a medium size (10 × 10 cm 2 ) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity (∼109 Ωcm). The 6.2 mm thick (excluding readout electronics) single-stage detector was studied with 150 GeV muons and pions. Signals were recorded from 1×1 cm 2 square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne/(5%CH4) at a gas gain of a few times 104 , reaching 99% detection efficiency at average pad multiplicity of ∼1.2. Operation at particle fluxes up to ∼104 Hz/cm 2 resulted in ∼23% gain drop leading to ∼5% efficiency loss. The striking feature was the discharge-free operation, also in intense pion beams. These results pave the way towards robust, efficient large-scale detectors for applications requiring economic solutions at moderate spatial and energy resolutions

  8. Improved corrosion resistance and interfacial contact resistance of 316L stainless-steel for proton exchange membrane fuel cell bipolar plates by chromizing surface treatment

    Science.gov (United States)

    Lee, S. B.; Cho, K. H.; Lee, W. G.; Jang, H.

    The electrochemical performance and electrical contact resistance of chromized 316 stainless-steel (SS) are investigated under simulated operating condition in a proton-exchange membrane fuel cell (PEMFC). The corrosion resistance of the chromized stainless steel is assessed by potentiodynamic and potentiostatic tests and the interfacial contact resistance (ICR) is examined by measuring the electrical contact resistance as a function of the compaction force. The results show that the chromizing surface treatment improves the corrosion resistance of the stainless steel due to the high-chromium concentration in the diffuse coating layer. On the other hand, the excess Chromium content on the surface increases the contact resistance of the steel plate to a level that is excessively high for commercial applications. This study examines the root cause of the high-contact resistance after chromizing and reports the optimum process to improve the corrosion resistance without sacrificing the ICR by obtaining a chrome carbide on the outer layer.

  9. A readout system for a cosmic ray telescope using Resistive Plate Chambers

    International Nuclear Information System (INIS)

    Resistive Plate Chambers (RPCs) are widely used in high energy physics for both tracking and triggering purposes. They have good time resolution and with finely segmented readout can also give a spatial resolution of better than 1 mm. RPCs can be produced cost-effectively on large scales, are of rugged build, and have excellent detection efficiency for charged particles. Our group has successfully built a Muon Scattering Tomography (MST) prototype, using 12 RPCs to obtain tracking information of muons going through a target volume of ∼ 50 cm × 50 cm × 70 cm, reconstructing both the incoming and outgoing muon tracks. We describe a readout system for fine-pitch RPCs using MAROC3 readout chips capable of scaling to a large system.

  10. A front-end electronics module for multi-gap resistive plate chambers

    International Nuclear Information System (INIS)

    Background: The output current signal of Multi-gap Resistive Plate Chambers (MRPCs) has low amplitude and fast speed. Purpose: Its amplitude and time information should be obtained in particle Time-of-Flight (TOF) detection. Methods: A simple electronics module for the presentation of the signals from MRPCs to standard existing digitization electronics is described. The circuit is based on 'off-the-shelf' discrete components. An optimization of the values of specific components is required to match the aspects of the MRPCs for the given application. The key electronic noise control plan is also discussed. Results: This electronics module has the excellent features including low prices, convenient making, easy assembling for testing system, etc. Conclusions: This electronics module is an attractive option for the front-end signal processing in MRPCs prototype and bench or beam-testing efforts, as well as in final implementations of small-area particle TOF system with existing data acquisition systems. (authors)

  11. An encoding readout method used for Multi-gap Resistive Plate Chambers (MRPCs) for muon tomography

    International Nuclear Information System (INIS)

    A muon tomography facility has been built in Tsinghua University. Because of the low flux of cosmic muon, an encoding readout method, based on the fine-fine configuration, was implemented for the 2880 channels induced signals from the Multi-gap Resistive Plate Chamber (MRPC) detectors. With the encoding method, the number of the readout electronics was dramatically reduced and thus the complexity and the cost of the facility was reduced, too. In this paper, the details of the encoding method, and the overall readout system setup in the muon tomography facility are described. With the commissioning of the facility, the readout method works well. The spatial resolution of all MRPC detectors are measured with cosmic muon and the preliminary imaging result are also given

  12. Web-based monitoring tools for Resistive Plate Chambers in the CMS experiment at CERN

    International Nuclear Information System (INIS)

    The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time

  13. Performance of 2nd Generation BaBar Resistive Plate Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Anulli, F.; Baldini, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Patteri, P.; Piccolo, M.; Zallo, A.; /Frascati; Cheng, C.H.; Lange, D.J.; Wright, D.M.; /LLNL,; Messner, R.; Wisniewski, William J.; /SLAC; Pappagallo, M.; /Bari U. /INFN, Bari; Andreotti, M.; Bettoni, D.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Negrini, M.; /Ferrara; Capra, R.; /Genoa U. /INFN, Genoa /Naples U. /INFN, Naples /Perugia U. /INFN, Perugia /Pisa U. /INFN, Pisa /Rome U. /INFN, Rome /Oregon U. /UC, Riverside

    2005-07-12

    The BaBar detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years. The RPCs experience widely different background and luminosity-driven singles rates (0.01-10 Hz/cm{sup 2}) depending on position within the endcap. Some regions have integrated over 0.3 C/cm{sup 2}. RPC efficiency measured with cosmic rays is high and stable. The average efficiency measured with beam is also high. However, a few of the highest rate RPCs have suffered efficiency losses of 5-15%. Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current. Studies of the above aging effects are presented and correlated with detector operating conditions.

  14. Performance of Resistive Plate Chambers installed during the first long shutdown of the CMS experiment

    CERN Document Server

    Shopova, M; Hadjiiska, R; Iaydjiev, P; Sultanov, G; Rodozov, M; Stoykova, S; Assran, Y; Sayed, A; Radi, A; Aly, S; Singh, G; Abbrescia, M; Iaselli, G; Maggi, M; Pugliese, G; Verwilligen, P; Van Doninck, W; Colafranceschi, S; Sharma, A; Benussi, L; Bianco, S; Piccolo, D; Primavera, F; Cimmino, A; Crucy, S; Rios, A A O; Tytgat, M; Zaganidis, N; Gul, M; Fagot, A; Bhatnagar, V; Singh, J; Kumari, R; Mehta, A; Ahmad, A; Awan, I M; Shahzad, H; Hoorani, H; Asghar, M I; Muhammad, S; Ahmed, W; Shah, M A; Cho, S W; Choi, S Y; Hong, B; Kang, M H; Lee, K S; Lim, J H; Park, S K; Kim, M S; Laktineh, I B; Lagarde, F; Gouzevitch, M; Grenier, G; Pedraza, I; Bernardino, S Carpinteyro; Estrada, C Uribe; Moreno, S Carrillo; Valencia, F Vazquez; Pant, L M; Buontempo, S; Cavallo, N; Fabozzi, F; Orso, I; Lista, L; Meola, S; Merola, M; Paolucci, P; Thyssen, F; Lanza, G; Esposito, M; Braghieri, A; Magnani, A; Riccardi, C; Salvini, P; Vai, I; Vitulo, P; Montagna, P; Ban, Y; Qian, S J; Choi, M; Choi, Y; Goh, J; Kim, D; Dimitrov, A; Litov, L; Petkov, P; Pavlov, B; Bagaturia, I; Lomidze, D; Avila, C; Cabrera, A; Sanabria, J C; Crotty, I; Vaitkus, J

    2016-01-01

    The CMS experiment, located at the CERN Large Hadron Collider, has a redundant muon system composed by three different detector technologies: Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central region) and Resistive Plate Chambers (both its central and forward regions). All three are used for muon reconstruction and triggering. During the first long shutdown (LS1) of the LHC (2013-2014) the CMS muon system has been upgraded with 144 newly installed RPCs on the forth forward stations. The new chambers ensure and enhance the muon trigger efficiency in the high luminosity conditions of the LHC Run2. The chambers have been successfully installed and commissioned. The system has been run successfully and experimental data has been collected and analyzed. The performance results of the newly installed RPCs will be presented.

  15. Eco-friendly gas mixtures for Resistive Plate Chambers based on Tetrafluoropropene and Helium

    CERN Document Server

    Abbrescia, M; Bianco, S; Ferrini, M; Muhammad, S; Passamonti, L; Pierluigi, D; Piccolo, D; Primavera, F; Russo, A; Saviano, G

    2016-01-01

    Due to the recent restrictions deriving from the application of the Kyoto protocol, the main components of the gas mixtures presently used in the Resistive Plate Chambers systems of the LHC experiments will be most probably phased out of production in the coming years. Identifying possible replacements with the adequate characteristics requires an intense R&D, which was recently started, also in collaborations across the various experiments. Possible candidates have been proposed and are thoroughly investigated. Some tests on one of the most promising candidate - HFO-1234ze, an allotropic form of tetrafluoropropane- have already been reported. Here an innovative approach, based on the use of Helium, to solve the problems related to the too elevate operating voltage of HFO-1234ze based gas mixtures, is discussed and the relative first results are shown.

  16. Wear-resistance and anti-scuffing of multi-arc ion plating molybdenum films

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-dou; XU Bin-shi; LIU Jia-jun; ZHUANG Da-ming

    2004-01-01

    The multi-arc ion plating technology was employed to prepare the molybdenum films with thickness of 3 μm on the AISI 1045 steel. The wear and scuffing tests were carried out on the ball-on-disc tester. AFM and SEM equipped with EDS were adopted to observe and analyze the morphologies and element compositions of surface,cross-section and worn scar of the Mo film. The phase structure was studied by XRD and the bonding strength between Mo film and substrate was measured by scratching tester. The tribological experiments show that the Mo film possesses a good wear-resistance and an excellent anti-scuffing property. The failure mechanism of Mo film under extreme condition is flaking off.

  17. Multigap resistive plate chambers for EAS study in the EEE Project

    CERN Document Server

    An, S; Badalà, A; Zichichi, A

    2007-01-01

    The EEE (Extreme Energy Events) Project, conceived by its leader Antonino Zichichi, is an experiment to study very high-energetic air showers (EAS) through the detection of the shower's muon component using a network of tracking detectors, installed in Italian high schools. The single tracking telescope is composed of three large area () Multi-gap Resistive Plate Chambers (MRPCs). The data collected by the telescopes will be used for studies of air showers and also for the search of time correlations between sites which are far apart. The first telescope, recently installed in the Liceo B. Touschek in Grottaferrata (Rome), is successfully running, and other telescopes are going to be installed in a short time in other towns, opening up the way for the first search of long-distance coincidences over a total area of .

  18. A large-area glass-resistive plate chamber with multistrip readout

    CERN Document Server

    Petrovici, M; Hildenbrand, K D; Augustinski, G; Ciobanu, M; Cruceru, I; Duma, M; Hartmann, O; Koczón, P; Kress, T; Marquardt, M; Moisa, D; Petris, M; Schröder, C; Simion, V; Stoicea, G; Weinert, J

    2002-01-01

    A completely new configuration of a glass resistive-plate chamber (GRPC) was built and tested. It consists of a double two-gap structure of electrodes with an active area of about 400 cm sup 2 and is read out via a central multistrip printed circuit board. In measurements with a sup 6 sup 0 Co source and p, d particles of 1.5 A GeV time resolutions better than 80 ps, position resolution along the strips of 5-6 mm and efficiencies larger than 95% were obtained using available fast standard electronics. These results open the possibility of constructing compact TOF detectors of high resolution and high granularity.

  19. Web-based monitoring tools for Resistive Plate Chambers in the CMS experiment at CERN

    CERN Document Server

    Kim, Min Suk

    2014-01-01

    The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time.

  20. A 200 cm x 50 cm large multigap resistive plate chamber based neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Yakorev, Dmitry; Elekes, Zoltan; Bemmerer, Daniel; Kempe, Mathias; Sobiella, Manfred; Stach, Daniel; Wagner, Andreas [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Roeder, Marko; Zuber, Kai [TU Dresden (Germany); Cowan, Thomas [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); TU Dresden (Germany)

    2012-07-01

    A prototype for a multigap resistive plate chamber (MRPC) based detector of 200 cm x 50 cm size for 1 GeV neutrons has been developed, built and tested. The principle of operation is the conversion of the high-energy neutron to a charged particle in an iron converter, and the detection of the charged particle in the MRPC. Experiments using the single-electron mode of operation of the ELBE 40 MeV electron accelerator showed that a time resolution of {sigma}{sub t}<100 ps was reached for minimum-ionizing particles, at nearly full efficiency. Extensive simulations show that it is feasible to construct a time-of-flight detector for GeV neutrons based on such a principle.

  1. Enhanced corrosion resistance and fuel cell performance of Al1050 bipolar plate coated with TiN/Ti double layer

    International Nuclear Information System (INIS)

    Highlights: • Aluminum has attracted interest as a bipolar plate material for PEMFC. • We investigated the effect of TiN–Ti and TiO2–Ti double layer coatings onto the Al1050 substrate. • TiN/Ti double layer coating exhibited the best performance of 30 times lower corrosion current density in anodic condition. - Abstract: In this study, we investigated the effects of TiN/Ti and TiO2/Ti double layer coatings, with a metal buffer layer, on the corrosion resistance, and electrical properties of Al1050 substrates for using them as bipolar plates in PEMFCs. TiN/Ti and TiO2/Ti double layers were deposited using the electromagnetic-field-superpositioned DC and RF magnetron sputtering method. The surface resistivity and contact resistance of the specimens were measured using the van der Pauw method and a previously reported interfacial contact resistance (ICR) measurement method, respectively. Further, the corrosion resistance of the specimens was characterized using electrochemical tests such as potentiodynamic and potentiostatic polarization tests. The results obtained in this study indicated that coating of the Al1050 substrates significantly increased the corrosion resistance of bipolar plates in the operating environment of a fuel cell when compared to uncoated substrates. In particular, the substrate coated with a TiN/Ti double layer exhibited the best performance: its corrosion current density was 30 times lower than that of an uncoated substrate under anodic conditions. Further, the Al1050 bipolar plate coated with a TiN/Ti double layer showed performance enhancement over an uncoated bipolar plate in an actual fuel cell test

  2. Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

    International Nuclear Information System (INIS)

    Highlights: ► We use the microorganism cells as forming templates to fabricate the bio-based conductive particles. ► The microorganism cells selected as forming templates are Spirulina platens, which are of natural helical shape and high aspect ratio. ► The sliver-coated Spirulina cells are a kind of lightweight conductive particles. ► The composites containing sliver-coated Spirulina cells exhibit a lower percolation value. - Abstract: In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of φc and t were obtained.

  3. Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

    Science.gov (United States)

    Cai, Jun; Lan, Mingming; Zhang, Deyuan; Zhang, Wenqiang

    2012-09-01

    In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of ϕ and t were obtained.

  4. Investigation of mass attenuation coefficients of water, concrete and bakelite at different energies using the FLUKA Monte Carlo code

    International Nuclear Information System (INIS)

    The mass attenuation coefficients of water, bakelite and concrete sample defined in the simulation package were obtained using the FLUKA Monte Carlo code at 59.5, 80.9, 140.5, 356.5, 661.6, 1173.2 and 1332.5 keV photon energies. The results for the mass attenuation coefficients obtained by simulation have been compared with experimental and the theoretical ones and good agreement has been observed. The results indicate that this process can be followed to determine the data on the attenuation of gamma-rays with the several energies in other materials. Also, the deposited energy by 661.6 keV photons at several thicknesses of each media was determined as being an important data for radiation shielding studies. (author)

  5. About the natural oscillations of orthotropic plate in the value problem of elasticity theory with viscous resistance

    OpenAIRE

    Zakaryan T.V.

    2013-01-01

    Natural spatial vibrations of orthotropic plates are considered, taking into account the internal viscous resistance, which is proportional to velocity of points of medium. First dynamic homogeneous boundary value problem of the elasticity theory is solved. The equations for frequencies are obtained by the asymptotic method. It’s shown that longitudinal and two types of shear natural vibrations are possible.

  6. About the natural oscillations of orthotropic plate in the value problem of elasticity theory with viscous resistance

    Directory of Open Access Journals (Sweden)

    Zakaryan T.V.

    2013-06-01

    Full Text Available Natural spatial vibrations of orthotropic plates are considered, taking into account the internal viscous resistance, which is proportional to velocity of points of medium. First dynamic homogeneous boundary value problem of the elasticity theory is solved. The equations for frequencies are obtained by the asymptotic method. It’s shown that longitudinal and two types of shear natural vibrations are possible.

  7. Investigation on impact resistance of steel plate reinforced concrete barriers against aircraft impact. Pt.1: Test program and results

    International Nuclear Information System (INIS)

    Steel plate reinforced concrete (SC) structures composed of concrete and steel plates with headed studs are considered to be more effective than RC structures against aircraft impact. This is due to the effects of the steel plates, especially the rear-face steel plates. Thus, their application to outer walls and roofs of risk-sensitive structures such as nuclear-related structures is expected to mitigate damage to critical components. However, few data have been available to understand and evaluate the complex behavior and damage process of SC panels against an aircraft impact. The objective of this study was to obtain valuable experimental and analytical data essential to investigate and establish a protection design method for SC structures against an aircraft impact. As a first step, impact tests using 1/7.5-scale models were carried out to clarify the damage phenomena caused by an aircraft crash into steel plate reinforced concrete (SC) panels. The results indicated that the steel plate, especially the rear-face plate, has a significant effect in preventing scattering of scabbed concrete debris. It was confirmed that SC panels have much better impact resistant performance than conventional reinforced concrete panels, enabling the thickness of protection panels to be reduced by approximately 30%. (authors)

  8. An electrochemical treatment to improve corrosion and contact resistance of stainless steel bipolar plates used in polymer electrolyte fuel cells

    Science.gov (United States)

    Gabreab, Ebrahim M.; Hinds, Gareth; Fearn, Sarah; Hodgson, David; Millichamp, Jason; Shearing, Paul R.; Brett, Daniel J. L.

    2014-01-01

    An electrochemical surface treatment is presented that improves the properties of stainless steel (316SS) used as bipolar plates for polymer electrolyte fuel cells (PEFCs). The process is an anodic treatment, whereby the material is polarised beyond the transpassive region. Potentiodynamic corrosion testing, chemical and morphological surface characterisation and interfacial contact resistance measurements indicate that the improved properties of 316SS are primarily a consequence of an enrichment of Cr at the near-surface of the material. The surface treatment increases the corrosion resistance and significantly reduces interfacial contact resistance.

  9. Studies of gaseous multiplication coefficient in isobutane using a resistive plate chamber

    International Nuclear Information System (INIS)

    Full text: Due to the increasing demands concerning High Energy Physics, Nuclear Medicine and other Nuclear Applications about gaseous detectors operating in high electric fields, many efforts have been done about the choice of filling gases that fulfill these requirements. In this context, the electron transport parameters in gases, as the gaseous multiplication coefficient, play an important role not only for detector design but also for simulation and modeling of discharges, allowing the validation of electron impact cross-sections. In the present work the preliminary measurements of gaseous multiplication coefficient, as function of the reduced electric field (from 36V/cm.Torr until 93V/cm.Torr), for isobutane are presented. Among several filling gases, isobutane is widely used in resistive plate chambers RPCs, and other gaseous detectors, due to its timing properties. Although its characteristics, there is a lack of swarm parameters data in literature for this gas, mainly at high electric fields. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. Considering the ratio between the current (I), measured in avalanche mode, and the primary ionization current (I0), the effective multiplication coefficient can be determined, since alpha = d-1ln(I/I0), where d is the gap between the electrodes. In our configuration, the experimental setup consists of two parallel plates enclosure in a stainless steel chamber at gas flow regime. The anode, is made of a high resistivity (2.1012Ω.cm) glass (3mm thick and 14mm diameter), while the cathode is of aluminium (40mm diameter). Primary electrons are produced by irradiating the cathode with a nitrogen laser (LTB MNL200-LD) and are accelerated toward the anode by means of a high voltage power supply (Bertan 225-30). In order to validate the technique and to analyze effects of non-uniformity, results for nitrogen, which has well

  10. Studies of gaseous multiplication coefficient in isobutane using a resistive plate chamber

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pontificia Univ. Catolica de Sao Paulo (PUC/SP), SP (Brazil); Lima, Iara B.; Vivaldini, Tulio C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Fonte, Paulo; Mangiarotti, Alessio [Universidade de Coimbra (Portugal). Dept. de fisica. Lab. de Instrumentacao e Fisica Experimental de Particulas

    2009-07-01

    Full text: Due to the increasing demands concerning High Energy Physics, Nuclear Medicine and other Nuclear Applications about gaseous detectors operating in high electric fields, many efforts have been done about the choice of filling gases that fulfill these requirements. In this context, the electron transport parameters in gases, as the gaseous multiplication coefficient, play an important role not only for detector design but also for simulation and modeling of discharges, allowing the validation of electron impact cross-sections. In the present work the preliminary measurements of gaseous multiplication coefficient, as function of the reduced electric field (from 36V/cm.Torr until 93V/cm.Torr), for isobutane are presented. Among several filling gases, isobutane is widely used in resistive plate chambers RPCs, and other gaseous detectors, due to its timing properties. Although its characteristics, there is a lack of swarm parameters data in literature for this gas, mainly at high electric fields. The experimental method used is based on the Pulsed Townsend technique, which follows from Townsend equation solution for a uniform electric field. Considering the ratio between the current (I), measured in avalanche mode, and the primary ionization current (I{sub 0}), the effective multiplication coefficient can be determined, since alpha = d{sup -1}ln(I/I{sub 0}), where d is the gap between the electrodes. In our configuration, the experimental setup consists of two parallel plates enclosure in a stainless steel chamber at gas flow regime. The anode, is made of a high resistivity (2.10{sup 12}{omega}.cm) glass (3mm thick and 14mm diameter), while the cathode is of aluminium (40mm diameter). Primary electrons are produced by irradiating the cathode with a nitrogen laser (LTB MNL200-LD) and are accelerated toward the anode by means of a high voltage power supply (Bertan 225-30). In order to validate the technique and to analyze effects of non-uniformity, results for

  11. Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Jun, E-mail: jun_cai@buaa.edu.cn [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Lan, Mingming; Zhang, Deyuan; Zhang, Wenqiang [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer We use the microorganism cells as forming templates to fabricate the bio-based conductive particles. Black-Right-Pointing-Pointer The microorganism cells selected as forming templates are Spirulina platens, which are of natural helical shape and high aspect ratio. Black-Right-Pointing-Pointer The sliver-coated Spirulina cells are a kind of lightweight conductive particles. Black-Right-Pointing-Pointer The composites containing sliver-coated Spirulina cells exhibit a lower percolation value. - Abstract: In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of {phi}{sub c} and t were obtained.

  12. Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV

    International Nuclear Information System (INIS)

    A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm2 area

  13. Response of multi-strip multi-gap resistive plate chamber

    International Nuclear Information System (INIS)

    A prototype of Multi-strip Multi-gap Resistive Plate chamber (MMRPC) with active area 40 cm × 20 cm has been developed at SINP, Kolkata. Detailed response of the developed detector was studied with the pulsed electron beam from ELBE at Helmholtz-Zentrum Dresden-Rossendorf. In this report the response of SINP developed MMRPC with different controlling parameters is described in details. The obtained time resolution (σt) of the detector after slew correction was 91.5 ± 3 ps. Position resolution measured along (σx) and across (σy) the strip was 2.8±0.6 cm and 0.58 cm, respectively. The measured absolute efficiency of the detector for minimum ionizing particle like electron was 95.8±1.3 %. Better timing resolution of the detector can be achieved by restricting the events to a single strip. The response of the detector was mainly in avalanche mode but a few percentage of streamer mode response was also observed. A comparison of the response of these two modes with trigger rate was studied

  14. A resistive plate chamber muon detector for the CMS experiment at LHC

    International Nuclear Information System (INIS)

    The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider at CERN will use Resistive Plate Chambers (RPCs) as a system for muon detection. RPCs will be also a relevant part of the dedicated muon trigger. The CMS barrel region will be equipped with 480 double gap RPCs operated in avalanche mode using a Freon based gas mixture. A great effort is being done to customize a detector able to satisfy the stringent requirements needed to operate in a hostile background environment during normal operation. Excellent muon efficiency, high rate capability, good time resolution, low cluster size and low neutron and gamma sensitivity will characterise the system. Such features have been carefully evaluated during the detector design and measured during the following R and D program. As the mass production started an intensive commitment period for monitoring the quality of the RPCs followed and involved researchers from Bari, Napoli, Pavia and Sofia Institutes. Production and assembling of the detectors was managed in Bari, Napoli, Sofia and at General Tecnica factory; cosmic rays tests in Pavia, Bari and Sofia assured the chambers final quality certification. Further tests at the CERN ISR site completed the process before the final installation on the experimental site. The detector performance will be analyzed in detail; the quality control procedures of the main RPC components will be reviewed as well as the cosmic test results for the mass production accomplished so far. Problems encountered and the adopted strategies for their solutions will be also discussed

  15. A new model for thermal contact resistance between fuel cell gas diffusion layers and bipolar plates

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2014-11-01

    A new analytical model is developed to predict the thermal contact resistance (TCR) between fibrous porous media such as gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells (PEMFCs) and flat surfaces (bipolar plates). This robust model accounts for the salient geometrical parameters of GDLs, mechanical deformation, and thermophysical properties of the contacting bodies. The model is successfully validated against experimental data, and is used to perform in a comprehensive parametric study to investigate the effects of fiber parameters such as waviness and GDL properties on the TCR. Fiber waviness, diameter and surface curvature, as well as GDL porosity, are found to have a strong influence on TCR whereas fiber length does not affect the TCR when the porosity is kept constant. Such findings provide useful guidance for design and manufacturing of more effective GDLs for PEMFC heat management. The analytic model can be readily implemented in simulation and modeling of PEMFCs, and can be extended with minor modifications to other fibrous porous media such as fibrous catalysts, insulating media and sintered metals.

  16. Degradation in the efficiency of glass Resistive Plate Chambers operated without external gas supply

    International Nuclear Information System (INIS)

    Resistive plate chambers (RPC) are particle detectors commonly used by the high energy physics community. Their normal operation requires a constant flow of gas mixture to prevent self-poisoning which reduces the chamber's capability to detect particles. We studied how quickly the efficiency of two RPCs drops when operated in sealed mode, i.e. without refreshing the gas mixture. The test aim is to determine how RPCs could be used as particle detectors in non-laboratory applications, such as those exploiting muon tomography for geological imaging or homeland security. The two sealed RPCs were operated in proportional mode for a period of more than three months, and their efficiencies were recorded continuously and analysed in 8-hours intervals. The results show that the efficiency drops on average by 0.79 ± 0.01 % every 24 hours of operation and returns close to the initial value after purging the old gas mixture and flushing the chambers with fresh gas

  17. The analog Resistive Plate Chamber detector of the ARGO-YBJ experiment

    CERN Document Server

    Bartoli, B; Bi, X J; Cao, Z; Catalanotti, S; Chen, S Z; Chen, T L; Cui, S W; Dai, B Z; D'Amone, A; Danzengluobu,; De Mitri, I; Piazzoli, B D'Ettorre; Di Girolamo, T; Di Sciascio, G; Feng, C F; Feng, Zhaoyang; Feng, Zhenyong; Gou, Q B; Guo, Y Q; He, H H; Hu, Haibing; Hu, Hongbo; Iacovacci, M; Iuppa, R; Jia, H Y; Labaciren,; Li, H J; Liu, C; Liu, J; Liu, M Y; Lu, H; Ma, L L; Ma, X H; Mancarella, G; Mari1, S M; Marsella, G; Mastroianni, S; Montini, P; Ning, C C; Perrone, L; Pistilli, P; Salvini1, P; Santonico, R; Shen, P R; Sheng, X D; Shi, F; Surdo, A; Tan, Y H; Vallania, P; Vernetto, S; Vigorito, C; Wang, H; Wu, C Y; Wu, H R; Xue, L; Yang, Q Y; Yang, X C; Yao, Z G; Yuan, A F; Zha, M; Zhang, H M; Zhang, L; Zhang, X Y; Zhang, Y; Zhao, J; Zhaxiciren,; Zhaxisangzhu,; Zhou, X X; Zhu, F R; Zhu, Q Q

    2015-01-01

    The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the YangBaJing Cosmic Ray Observatory (4300 m a.s.l.). The detector consists of a single layer of Resistive Plate Chambers (RPCs) ( about 6700 m^2}) operated in streamer mode. The signal pick-up is obtained by means of strips facing one side of the gas volume. The digital readout of the signals, while allows a high space-time resolution in the shower front reconstruction, limits the measurable energy to a few hundred TeV. In order to fully investigate the 1-10 PeV region, an analog readout has been implemented by instrumenting each RPC with two large size electrodes facing the other side of the gas volume. Since December 2009 the RPC charge readout has been in operation on the entire central carpet (about 5800 m^2). In this configuration the detector is able to measure the particle density at the core position where it ranges from tens to many thousands of particles per m^2. Thus ARGO-YBJ provides a highly detailed...

  18. Front-End electronics development for the new Resistive Plate Chamber detector of HADES

    Science.gov (United States)

    Gil, A.; Belver, D.; Cabanelas, P.; Díaz, J.; Garzón, J. A.; González-Díaz, D.; Koenig, W.; Lange, J. S.; Marín, J.; Montes, N.; Skott, P.; Traxler, M.

    2007-11-01

    In this paper we present the new RPC wall, which is being installed in the HADES detector at Darmstadt GSI. It consists of time-of-flight (TOF) detectors used for both particle identification and triggering. Resistive Plate Chamber (RPC) detectors are becoming widely used because of their excellent TOF capabilities and reduced cost. The wall will contain 1024 RPC modules, covering an active area of around 7 m2, replacing the old TOFino detector at the low polar angle region. The excellent TOF and good charge resolutions of the new detector will improve the time resolution to values better than 100 ps. The Front-End electronics for the readout of the RPC signals is implemented with two types of boards to satisfy the space constraints: the Daughterboards are small boards that amplify the low level signals from the detector and provide fast discriminators for time of flight measurements, as well as an integrator for charge measurements. The Motherboard provides stable DC voltages and a stable ground, threshold DACs for the discriminators, multiplicity trigger and impedance matched paths for transfer of time window signals that contain information about time and charge. These signals are sent to a custom TDC board that label each event and send data through Ethernet to be conveniently stored.

  19. Studies of purification of the Resistive Plate Chamber gas mixture for the Large Hadron Collider experiments

    CERN Document Server

    Capeans, M; Guida, R; Hahn, F; Haider, S

    2009-01-01

    The Resistive Plate Chambers (RPCs) installed as part of the large muon detectors at the Large Hadron Collider (LHC) experiments use a gas mixture of 94.7% C2H2F4, 5% iC(4)H(10) and 0.3% SF6. Based on economical grounds, the design philosophy of the gas systems for the ATLAS and CMS RPC's foresees to recirculate the gas mixture in 90-95% closed loop circulation. At the LHC, RPC chambers are operated in a high radiation environment, conditions for which large amount of impurities in the return gas have been observed in earlier studies. They are potentially dangerous for the stable operation of the detectors, the materials in the detector and the gas system. While several purification stages have been foreseen in the present gas systems, chemical reactions between the absorber and the impurities are yet not well understood. Furthermore, the effects on the gas mixture of the foreseen factor 10 increase of luminosity for the LHC upgraded phase should be studied. We present the results of systematic studies of the...

  20. Testing of multigap Resistive Plate Chambers for Electron Ion Collider Detector Development

    Science.gov (United States)

    Hamilton, Hannah; Phenix Collaboration

    2015-10-01

    Despite decades of research on the subject, some details of the spin structure of the nucleon continues to be unknown. To improve our knowledge of the nucleon spin structure, the construction of a new collider is needed. This is one of the primary goals of the proposed Electron Ion Collider (EIC). Planned EIC spectrometers will require good particle identification. This can be provided by time of flight (TOF) detectors with excellent timing resolutions of 10 ps. A potential TOF detector that could meet this requirement is a glass multigap resistive plate chamber (mRPC). These mRPCs can provide excellent timing resolution at a low cost. The current glass mRPC prototypes have a total of twenty 0.1 mm thick gas gaps. In order to test the feasibility of this design, a cosmic test stand was assembled. This stand used the coincidence of scintillators as a trigger, and contains fast electronics. The construction, the method of testing, and the test results of the mRPCs will be presented.

  1. Analysis and interpretation of the performance degradation of glass Resistive Plate Chambers operated in streamer mode

    CERN Document Server

    Calcaterra, A; Patteri, P; Piccolo, M; Della Mea, G; Restello, S; Ferri, F; Musella, P; Redaelli, N; Tabarelli de Fatis, T; Tinti, G; Mannocchi, G; Trinchero, G

    2007-01-01

    The long-term stability of Resistive Plate Chambers (RPCs) with glass electrodes was studied for one year with a dedicated test station hosting about 10 m2 of detectors. RPCs were operated in streamer mode with a ternary gas mixture containing argon (27%), isobutane (9%) and tetrafluoroethane (64%). Environmental conditions were kept under control and, in particular, the water pollution in the gas, deemed responsible for the degradation of glass RPC performance, was monitored never to exceed 30 ppm in the exhaust line. Evidence for a substantial aging of the detectors was observed, resulting in a loss of efficiency correlated to an increased rate of spurious streamers. This can be ascribed to the chemical attack of the glass surface by hydrofluoric acid formed in the streamer process, as confirmed by detailed morphological and chemical analyses of the electrode surface. Our results strengthen the indication that the instability of glass RPCs in the long term is related to the use of fluorocarbons as quenching...

  2. Signal Efficiency of the Resistive Plate Chambers in the PHENIX Forward Trigger Upgrade

    Science.gov (United States)

    Coley, Mark

    2009-10-01

    PHENIX is an experiment at the Relativistic Heavy Ion Collider (RHIC) that studies polarized proton-proton and heavy ion collisions. PHENIX is in the process of upgrading the forward muon trigger to improve its capabilities of studying W-bosons. By triggering on single, high transverse momentum muons, new observations on the spin structure of a proton will be obtained. The trigger upgrade will consist of four stations of Resistive Plate Chambers (RPCs) with two stations on each side of the interaction region. Inside an RPC, there are several copper strips which form a signal plane. When a charged particle travels through the adjacent gas gaps a signal is induced on these strips. This signal propagates from the copper strip to the readout electronics. In the readout electronics, the signal is amplified and sent to a discriminator. Care must be taken when setting the chamber high voltage and the readout electronics threshold to balance the detector efficiency and noise. Lowering the threshold increases the efficiency of detecting muons but also increases the background interference. These RPCs are tested on a cosmic ray test stand to determine the optimal operating conditions. This poster will describe the RPCs, how the signal propagates out of the chamber and how the high voltage and threshold affect performance.

  3. Performance and operation of the ATLAS Resistive Plate Chamber system in LHC Run-1

    CERN Document Server

    Boscherini, D; The ATLAS collaboration

    2014-01-01

    The barrel region of the ATLAS muon spectrometer is instrumented with a Resistive Plate Chamber (RPC) system covering the pseudo-rapidity range |η|<1.05 with a detector surface of almost 4000 m2. The RPCs, providing the first level trigger signal and the track coordinate in the non-bending plane for the candidate muons, have played a fundamental role in the physics studies carried out by ATLAS, culminated with the discovery of the Higgs boson. During the LHC Run-1 the RPC have shown excellent performances up to the maximum instantaneous luminosity of 0.7 × 1034 cm−2 s−1, corresponding approximately to 70% of the design value. The detector operation in the challenging background and pileup conditions of the LHC environment will be presented together with the problems encountered and their corresponding solutions. The plans for the maintenance and consolidation of the ATLAS RPC system during the current LHC shutdown, in view of the increased luminosity expected in Run-2, will be also presented.

  4. Development and Evaluation of the Muon Trigger Detector Using a Resistive Plate Chamber

    International Nuclear Information System (INIS)

    The PHENIX Experiment is the largest of the four experiments that have taken data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. Among many particles, muons coming from W-boson decay gives us key information to analyze the spin of proton. Resistive plate chambers are proposed as a suitable solution as a muon trigger because of their fast response and good time resolution, flexibility in signal readout, robustness and the relatively low cost of production. The RPC detectors for upgrade were assembled and their performances were evaluated. The procedure to make the detectors better was optimized and described in detail in this thesis. The code based on ROOT was written and by using this the performance of the detectors made was evaluated, and all of the modules for north muon arm met the criteria and installation at PHENIX completed in November 2009. As RPC detectors that we made showed fast response, capacity of covering wide area with a resonable price and good spatial resolution, this will give the opportunity for applications, such as diagnosis and customs inspection system

  5. Development and Evaluation of the Muon Trigger Detector Using a Resistive Plate Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byeong Hyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Yong Kyun; Kang, Jeong Soo [Hanyang University, Seoul (Korea, Republic of); Kim, Young Jin; Choi, Ihn Jea [Brookhaven National Laboratory, Brookhaven (United States); Kim, Chong; Hong, Byung Sik [Korea University, Seol (Korea, Republic of)

    2011-03-15

    The PHENIX Experiment is the largest of the four experiments that have taken data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. Among many particles, muons coming from W-boson decay gives us key information to analyze the spin of proton. Resistive plate chambers are proposed as a suitable solution as a muon trigger because of their fast response and good time resolution, flexibility in signal readout, robustness and the relatively low cost of production. The RPC detectors for upgrade were assembled and their performances were evaluated. The procedure to make the detectors better was optimized and described in detail in this thesis. The code based on ROOT was written and by using this the performance of the detectors made was evaluated, and all of the modules for north muon arm met the criteria and installation at PHENIX completed in November 2009. As RPC detectors that we made showed fast response, capacity of covering wide area with a resonable price and good spatial resolution, this will give the opportunity for applications, such as diagnosis and customs inspection system.

  6. The resistive plate WELL detector as a single stage thick gaseous multiplier detector

    Energy Technology Data Exchange (ETDEWEB)

    Bressler, Shikma; Breskin, Amos; Moleri, Luca; Kumar, Ashwini; Pitt, Michael [Department of Particle Physics and Astrophysics, Weizmann Institute of Science (WIS) (Israel); Kudella, Simon [Institut fuer Experimentelle Kernphysik (IEKP), KIT (Germany)

    2015-07-01

    Gaseous Electron Multiplier (GEM) detector use high electric fields inside the h ole of a foil to achieve a high charge multiplication. As a thicker version of G EMs based on printed circuit board (PCB) structures, Thick Gaseous Electron Multiplier (THGEM) detectors combine the high gain of a GEM foil with the robustness, stability and low production costs of a PCB and allow a large quantity of applications that require the coverage of a large area at low cost and moderate spatial resolution. One application the Weizmann Institute of Science (WIS) develops as a member of the RD51 framework is the Resistive Plate WELL (RPWELL) detector. This single stage detector allows a very stable, discharge free operation at high gain (10{sup 5}). The single stage operation allows a low total height and make s the RPWELL a candidate for the Digital Hadronic Calorimeter (DHCAL) of the International Large Detector (ILD) at the International Linear Collider (ILC). The talk gives an insight into the way the RPWELL works and shows results from the last test beam.

  7. Simulation of efficiency and time resolution of resistive plate chambers and comparison with experimental data

    International Nuclear Information System (INIS)

    The India based Neutrino Observatory (INO) collaboration is planning to build a 50 kton magnetized Iron Calorimeter (ICAL) detector to study neutrino oscillations and measure their associated parameters. ICAL will use 28,800 glass Resistive Plate Chambers (RPCs) of 2 m×2 m in size as its active detector elements. These RPCs will be operated in the avalanche mode. As a part of the detector R and D to develop the RPCs required for this detector, we made a comparative study of the effect of Sulphur Hexafluoride (SF6) in the gas mixture on the induced charge using simulation and experimental data in our earlier paper [1]. In this paper, we extend our studies to efficiency and time resolution of the RPC using simulation and experimental data. Several software tools have been used to carry out the simulation. We have calculated the primary interaction parameters using HEED and Geant4. The electron transport parameters have been computed using MAGBOLTZ. We have used nearly exact Boundary Element Method (neBEM) and COMSOL Multiphysics, a Finite Element Method package for calculating the weighting field and the electric field

  8. Effect of surface treatment on the interfacial contact resistance and corrosion resistance of Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    The bipolar plate is an important component of the PEMFC (polymer electrolyte membrane fuel cell) because it supplies the pathway of electron flow between each unit cell. Fe–Ni–Cr alloy is considered as a good candidate material for bipolar plate, but it is limited to use as a bipolar plate due to its high ICR (interfacial contact resistance) and corrosion problem. In order to explore a cost-effective method on surface modification, various chemical and electrochemical treatments are performed on Fe–Ni–Cr alloy to acquire the effect of the surface modification on the ICR and corrosion behavior. The ICR and corrosion resistance of Fe–Ni–Cr alloy can be effectively controlled by the chemical treatment of immersion in the mixed acid solution with 10 vol% HNO3, 2 vol% HCl and 1 vol% HF for 10 min at 65 °C and then was placed in 30 vol% HNO3 solution for 5 min. The chemical treatment is more effective on reducing ICR and improving corrosion resistance than that of electrochemical methods (be carried out in the 2 mol/L H2SO4 solution with the electrical potential from −0.4 V to 0.6 V) for Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells. - Highlights: • The procedure of the surface treatments on Fe–Ni–Cr alloy as bipolar plate was described in detail. • Effects of various surface treatments on the interfacial contact resistivity and corrosion behavior were discussed. • The mechanism of the surface modification was particularly analyzed

  9. Ageing tests on the low-resistivity RPC for the ALICE dimuon arm

    International Nuclear Information System (INIS)

    The trigger for the Dimuon Forward Spectrometer of the forthcoming ALICE experiment at CERN LHC will be provided by low-resistivity, single gap Resistive Plate Chambers working in streamer mode. Different ageing test were performed to measure and improve the life-time of the detector. Dummy chambers have been built to understand the effects of continuous gas flow upon the Bakelite resistivity: the results concerning our standard gas mixture (49% Ar, 40% forane, 7% isobutane and 4% SF6) are reported, and compared with the same mixture in which ∼1% of water vapor is added. Moreover, two ageing test of 1 month each have been carried out at the Gamma Irradiation Facility at CERN during 2001. The efficiency for cosmic rays under γ irradiation of RPCs coated with different thicknesses of linseed oil was measured. After protracted operation, the detectors have shown an increase of the current and of the background rate. The increase is slower in the chamber with a thicker oil coating

  10. Ageing tests on the low-resistivity RPC for the ALICE dimuon arm

    CERN Document Server

    Arnaldi, R; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; De Marco, N; Dellacasa, G; Drancourt, C; Dupieux, P; Espagnon, B; Ferretti, A; Forestier, B

    2003-01-01

    The trigger for the Dimuon Forward Spectrometer of the forthcoming ALICE experiment at CERN LHC will be provided by low-resistivity, single gap Resistive Plate Chambers working in streamer mode. Different ageing test were performed to measure and improve the life- time of the detector. Dummy chambers have been built to understand the effects of continuous gas flow upon the Bakelite resistivity: the results concerning our standard gas mixture (49% Ar, 40% forane, 7% isobutane and 4% SF//6) are reported, and compared with the same mixture in which similar to 1% of water vapor is added. Moreover, two ageing test of 1 month each have been carried out at the Gamma Irradiation Facility at CERN during 2001. The efficiency for cosmic rays under gamma irradiation of RPCs coated with different thicknesses of linseed oil was measured. After protracted operation, the detectors have shown an increase of the current and of the background rate. The increase is slower in the chamber with a thicker oil coating.

  11. Increase of bending fatigue resistance for tungsten inert gas welded SS400 steel plates using friction stir processing

    International Nuclear Information System (INIS)

    Highlights: • The first time FSP modification of bending properties in the TIG-welded steel plates. • FSP produced about 40% increase in bending strength at RT. • FSP produced about 170% increase in the number of cycles to failure at 270 MPa at RT. • FSP produced a zigzag-shaped crack at the fatigue fracture start portion. • A fine-grained FSP region (grain sizes of about 1–2 μm in diameter) was observed. - Abstract: To improve the fatigue resistance of tungsten inert gas (TIG)-welded SS400 steel plates, friction stir processing (FSP) was performed on TIG weld beads. Although the tensile properties of the TIG-welded steel plates with FSP were similar to those without FSP, their bending strength exhibited about 1.4 GPa at room temperature, which was 40% higher than that without FSP (about 1 GPa). Similarly, FSP produced about 170% increase in the number of cycles to failure at an applied stress amplitude of 270 MPa during three-point bending fatigue at room temperature. A fine-grained FSP region (grain sizes of about 1–2 μm in diameter) enhanced grain-boundary strengthening, leading to the higher bending strength and bending fatigue resistance

  12. Development of multi-gap resistive plate chambers with low-resistive silicate glass electrodes for operation at high particle fluxes and large transported charges

    International Nuclear Information System (INIS)

    Using electrodes made of semi-conductive glass is an innovative way of improving the rate capability of resistive plate chambers. To address this issue, we developed 6- and 10-gap counters with low-resistive silicate glass electrodes (bulk resistivity ∼1010 Ω cm) suited for time-of-flight (TOF) applications at high rates and high transported charges. Measurements were performed at GSI-Darmstadt under uniform an irradiation by secondary particles stemming from proton reactions at 2.5 GeV/A. For the 10-gap MRPC, time resolutions below 90 ps and efficiencies larger than 90% were obtained at counting rates up to 25 kHz/cm2. When the particle flux increases every 5 kHz/cm2, the efficiency decreases by 1% and the time resolution deteriorates by 4 ps. A tolerable decrease of the material conductivity was also observed for a total transported charge of 1 C/cm2.

  13. Corrosion resistance of hybrid films applied on tin plate: Precursor solution acidified with nitric acid (pH=3

    Directory of Open Access Journals (Sweden)

    Sandra R. Kunst

    2014-01-01

    Full Text Available Siloxane – poly (methylmethacrylate-based materials are system s formed by a silicon network, to which chains of poly (methylmethacrylate are linked by covalent bonds or by physica l interactions. Their stability and adherence allow their appli cation on substrates like tin plate in order to increase the corrosion re sistance. The aim of this work is to coat tin plate with a hybr id film obtained from a sol consisting of alkoxide precursors: 3 - (trimethoxysi lylpropyl methacrylate (TMSM and poly (methyl methacrylate P MMA. Effect of tetraethoxysilane (TEOS addition was evaluated. Morp hology was evaluated by SEM and contact angle. Electrochemical behavior was evaluated by open circuit potential (OCP, potenti odynamic polarization and electrochemical impedance spectroscop y (EIS. Results showed that siloxane-PMMA film obtained with a higher a ddition of TEOS had higher thickness. However, intense densific ation caused by TEOS addition promoted crack formation, thereby compr omising the corrosion resistance.

  14. A study on the effect of flat plate friction resistance on speed performance prediction of full scale

    Directory of Open Access Journals (Sweden)

    Park Dong-Woo

    2015-01-01

    Full Text Available Flat plate friction lines hare been used in the process to estimate speed performance of full-scale ships in model tests. The results of the previous studies showed considerable differences in determining form factors depending on changes in plate friction lines and Reynolds numbers. These differences had a great influence on estimation of speed performance of full-scale ships. This study- was conducted in two parts. In the first part, the scale effect of the form factor depending on change in the Reynolds number was studied based on CFD, in connection with three kinds of friction resistance curves: the ITTC-1957, the curve proposed by Grigson (1993; 1996, and the curve developed by Katsui et al (2005. In the second part, change in the form factor by three kinds of

  15. Corrosion resistance of zinc-nickel plated U-O.75 Ti

    International Nuclear Information System (INIS)

    As part of a program for the US Army directed at improving the corrosion performance of U-0.75 Ti, specimens were coated with Zn-10 Ni alloy electroplate and then subjected to various corrosion tests. This work revealed that the Zn-Ni coatings provided good protection for U-0.75 Ti in salt fog and in non-sealed moist-nitrogen systems. In sealed, moist-nitrogen environments the Zn-Ni coatings deteriorated quickly and provided no protection. Some plating with Zn alone, using some of the new non-cyanide plating solutions, was also attempted, but the results were inconsistent

  16. Sensitivity and statistical analysis within the elaboration of steel plated girder resistance

    Czech Academy of Sciences Publication Activity Database

    Melcher, J.; Škaloud, Miroslav; Kala, Z.; Karmazínová, M.

    2009-01-01

    Roč. 5, č. 2 (2009), s. 120-126. ISSN 1816-112X. [International conf. on steel and aluminium structures /6./. Oxford, 24.06.2007-27.06.2007] Institutional research plan: CEZ:AV0Z20710524 Keywords : steel structures * fatigue * sensitivity * imperfection * plated girder Subject RIV: JM - Building Engineering

  17. Synthesis of Corrosion-resistant Nanocrystalline Nickle-copper Alloy Coatings by Pulse-plating Technique

    Directory of Open Access Journals (Sweden)

    S.K. Ghosh

    2005-01-01

    Full Text Available Bright and smooth nanocrystalline Monel-type Ni-Cu alloy gets deposited from complex citrate electrolyte by pulse electrolysis. Transmission electron microscopy studies have revealedthat the deposited Ni-Cu alloy was nanocrystalline in nature and it comprised a two-phase (fcc+Ll, mixture. The presence of twins could be seen in the nanocrystals. The Ni-Cu alloysprepared by pulse electrolysis were finer grained (- 2.5-28.5 nm than those deposited by direct current method. Nelson-Riley function has been used to calculate the lattice parameters for both the pulse current-plated and direct current-plated alloys from x-ray diffraction analysis. The microhardness values for pulse current-plated alloys were higher than for the direct currentplated alloys. The internal stresses of both the pulse current-deposited and the direct currentdeposited alloys have also been measured; the values were lower for pulse current-plated alloys. Potentiodynamic polarisation studies were carried out in aerated and deaerated neutral 3.0 Wt per cent NaCl solution and instantaneous corrosion current density of the plated alloy was determined and compared with the Monel-400 alloy. It was found that nanocrystalline pulse current-N,-35 8 Wt p;r cent copper alloy uxh~bitedlo wer instantaneous value of corros~onc urrent densirv than that of soeclrnens with direct current method and Monel-400 allov The d~ssolut~on ~ ~~~~-~ behaviour ofthe deposited nanocrystalline material was found to be more like general corrosion rather than localised corrosion as in the case of Monel-400 alloy.

  18. Assessment of the Resistance of a Polymethylmethacrylate (Pmma Dynamic Compression Plate (DCP Prototype Tested on Osteotomized Canine Femurs

    Directory of Open Access Journals (Sweden)

    Leonel Cardona R.

    2011-06-01

    Full Text Available Femur fractures are the most frequent long bone fractures in small animals. Due to the femur’s anatomical position, it is difficult to immobilize, and therefore internal fixations are very useful. Dynamic compression plates (DCP provide high stability, are durable, minimize fragment movement and promote primary healing of the bone. Advantages of this treatment include anatomical reconstruction, early mobility and carrying capacity of the affected limb. Polymethylmethacrylate (PMMA is an acrylic resin that has proved very useful in bone tumor treatment, cranial deformation prosthesis, percutaneous vertebroplasty and testicular prosthesis in animals. The purpose of this study was to manufacture DCP-PMMA and test its resistance to the different forces present in a fracture. Forty-eight (48 3.5MM x 4-hole DCP were made from an alginate mold. Six (6 femurs were obtained from canine cadavers zeighing from 10 to 20 kg, which underwent osteotomy simulating an oblique fracture. The plates were subsequently positioned in the osteotomized bones to submit them to the various forces involved in a fracture. The DCP-PMMA resisted a torque force of 2.83 newton/metres and a compression and flexion force of 0.21 kilonewton. The obtained resistance of the DCP-PMMA was an average of 20 kg per force. The results of this study show that it is possible to make a DCP-PMMA 3.5 mm x 4-hole, the resistance of which is of 20 kg against the three applied forces, and that it can be used to stabilize long bone fractures subjected to a pressure of less than 20 kg.

  19. A low resistivity RPC for the trigger of the ALICE di-muon arm

    CERN Document Server

    Ferretti, A; Baldit, A; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; Dellacasa, G; De Marco, N; Drancourt, C; Dupieux, P; Espagnon, B; Forestier, B; Gallio, M; Genoux-Lubain, A; Insa, C; Jouve, F; Lamoine, L; Lefèvre, F; Manso, F; Mereu, P; Musso, A; Oppedisano, C; Piccotti, A; Rosnet, P; Royer, L; Saturnini, P; Scalas, E; Scomparin, E; Sigaudo, F; Vercellin, Ermanno

    2001-01-01

    Resistive Plate Chambers (RPC) operated in streamer mode are expected to provide the trigger of the ALICE dimuon forward spectrometer. To match the requirements concerning the rate capability (about 100 Hz/cm2, including a large safety factor), several prototypes have been realized with low-resistivity Bakelite electrodes and a strongly quenching gas mixture. Duringb eam and irradiation tests the detector has shown a stable behaviour and excellent rate capability (up to 1 kHz/cm 2 in eam tests) with a cluster size close to one. In addition to that,a new discrimination technique with a dual threshold has been devised: with this method, a time resolution comparable with the one typical of the avalanche mode can be obtained as soon as the applied voltage is sufficient for the RPC to reach full efficiency. In the presentation the performances of the detector will be reported, together with the results of ageing tests performed at the Gamma Irradiation Facility at CERN.

  20. Differential biofilm formation and chemical disinfection resistance of Escherichia coli on stainless steel and polystyrene tissue culture plate

    Directory of Open Access Journals (Sweden)

    Anas Muazu

    2015-11-01

    Full Text Available Background: Biofilms are aggregates of microbial cells enclosed in an extracellular polymeric substance and attached to surfaces. Biofilm formation and its resistance to antimicrobials is becoming a serious challenge in food industries and hospital settings. The aim of this work was to study the formation of biofilm by E. coli on Stainless steel (SS and Polystyrene Tissue Culture Plate (TCP at 10 and 27 and deg;C, and also to assess the action Hydrogen Peroxide (HP, Para Acetic Acid (PAA, Sodium Hypochlorite (SH and mixture of PAA + SH disinfectants against the biofilm. Methods: 200 and micro;L of 108 suspension of E. coli ATCC 29922 was inoculated on the SS and into the wells of TCP, incubated at 10 and 27 and deg;C for 24, 48 72 and 168 hours. Biofilm developed at each incubation hour above was quantified by bead-vortex method followed by agar plating. The action of disinfectants was tested on 168 hours biofilm. The surfaces were exposed to the disinfectants and incubated at 27 and deg;C for 10 minutes, followed by deactivation for 5 minutes. Cells that resisted disinfectants action were vortexed and enumerated by agar plating. Results: From the results E. coli developed higher biofilm on SS than TCP at 72 hours and 27 and deg;C. After disinfection, HP was the most effective with log reduction value of 1.11 followed by PAA (1.07, then PAA + SH (1.04 while SH was the least (0.92. Conclusions: The result of this work showed that HP and PAA can be good disinfectants against E. coli biofilm. [Int J Res Med Sci 2015; 3(11.000: 3300-3307

  1. Effects of Mo content on microstructure and corrosion resistance of arc ion plated Ti-Mo-N films on 316L stainless steel as bipolar plates for polymer exchange membrane fuel cells

    Science.gov (United States)

    Zhang, Min; Kim, Kwang Ho; Shao, Zhigang; Wang, Feifei; Zhao, Shuang; Suo, Ni

    2014-05-01

    Bipolar plates are one of the most important components in PEMFC stack and have multiple functions, such as separators and current collectors, distributing reactions uniformly, and etc. Stainless steel is ideal candidate for bipolar plates owing to good thermal and electrical conductivity, good mechanical properties etc. However, stainless steel plate still cannot resist the corrosion of working condition. In this work, ternary Ti-Mo-N film was fabricated on 316L stainless steel (SS316L) as a surface modification layer to enhance the corrosion resistance. Effects of Mo content on the microstructure and corrosion resistance of Ti-Mo-N films are systematically investigated by altering sputtering current of the Mo target. XRD results reveal that the preferred orientation changes from [111] to [220] direction as Mo content in the film increases. The synthesized Ti-Mo-N films form a substitutional solid solution of (Ti, Mo)N where larger Mo atoms replace Ti in TiN crystal lattice. The TiN-coated SS316L sample shows the best corrosion resistance. While Mo content in the Ti-Mo-N films increases, the corrosion resistance gradually degrades. Compared with the uncoated samples, all the Ti-Mo-N film coated samples show enhanced corrosion resistance in simulated PEMFC working condition.

  2. Effects of SF$_{6}$ on the avalanche mode operation of a real-sized double-gap resistive plate chamber for the Compact Muon Solenoid experiment

    CERN Document Server

    Ahn Sung Hwan; Hong, B; Hong, S J; Ito, M; Kim, B I; Kim, J H; Kim, Y J; Kim, Y U; Koo, D G; Lee, H W; Lee, K B; Lee, K S; Lee, S J; Lim, J K; Moon, D H; Nam, S K; Park, S; Park, W J; Rhee, J T; Ryu, M S; Shim, H H; Sim, K S; Kang, T I

    2005-01-01

    We present the design and the test, results for a real-sized prototype resistive plate chamber by using cosmic-ray muons for the forward region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). In particular, we investigate the effects of adding SF/sub 6/ to the gas mixture for the avalanche mode operation of a resistive plate chamber. A small fraction of SF/sub 6/ is very effective in suppressing streamer signals in a resistive plate chamber. The shapes of the muon detection efficiency and the muon cluster size remain similar, but are shifted to higher operating voltage by SF/sub 6/. The noise cluster rate and size are not influenced by SF/sub 6/.

  3. Preliminary results of Resistive Plate Chambers operated with eco-friendly gas mixtures for application in the CMS experiment

    CERN Document Server

    Abbrescia, Marcello; Benussi, Luigi; Bianco, Stefano; Cauwenbergh, Simon Marc D; Ferrini, Mauro; Muhammad, Saleh; Passamontic, L; Pierluigi, Daniele; Piccolo, Davide; Primavera, Federica; Russo, Alessandro; Savianoc, G; Tytgat, Michael

    2016-01-01

    The operations of Resistive Plate Chambers in LHC experiments require F-based gases for optimal performance. Recent regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. In view of the CMS experiment upgrade several tests are ongoing to measure the performance of the detector in terms of efficiency, streamer probability, induced charge and time resolution. Prototype chambers with readout pads and with the standard cms electronic setup are under test. In this talk preliminary results on performance of RPCs operated with a potential eco-friendly gas candidate 1,3,3,3-Tetrafluoropropene, commercially known as HFO-1234ze and with CO2 based gas mixtures are presented and discussed for the possible application in the CMS experiment.

  4. Preliminary results of Resistive Plate Chambers operated with eco-friendly gas mixtures for application in the CMS experiment

    CERN Document Server

    Abbrescia, M; Benussi, L.; Bianco, S.; Cauwenbergh, S.; Ferrini, M.; Muhammad, S.; Passamonti, L.; Pierluigi, D.; Piccolo, D.; Primavera, F.; Russo, A.; Saviano, G.; Tytgat, M.

    2016-01-01

    The operations of Resistive Plate Chambers in LHC experiments require Fluorine based (F-based) gases for optimal performance. Recent European regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. In view of the CMS experiment upgrade, several tests are ongoing to measure the performance of the detector with these new ecological gas mixtures, in terms of efficiency, streamer probability, induced charge and time resolution. Prototype chambers with readout pads and with the standard CMS electronic setup are under test. In this paper preliminary results on performance of RPCs operated with a potential eco-friendly gas candidate 1,3,3,3-Tetrafluoropropene, commercially known as HFO-1234ze, with CO2 and CF3I based gas mixtures are presented and discussed for the possible application in the CMS experiment.

  5. Sodium functionalized graphene oxide coated titanium plates for improved corrosion resistance and cell viability

    International Nuclear Information System (INIS)

    Surface functionalization is an important process that has been adopted to well explore the applications of nanomaterials. In this context, we demonstrate the sodium functionalized graphene oxide (NaGO) as an excellent candidate for increasing the life time of titanium (Ti) based ortho-implants. As-prepared aqueous dispersion of NaGO was used to assemble NaGO sheets on commercially pure Ti (CpTi) plates by heat controlled spin coating. The resulting wrinkled NaGO sheets play a dual role in implant material, i.e., passive layer against corrosion and biocompatible scaffold for cell viability. The preparation, physicochemical properties, and biocompatibility of NaGO coatings formed on CpTi were reported. The electrochemical polarization studies demonstrate the relative susceptibility of control GO and NaGO coatings to corrosion, which outline that the NaGO coating act as a geometric blocking layer and hence prevent the implant surface from contacting corrosive media. The immunofluorescence and cell proliferation studies performed using human dermal fibroblasts cells showed that NaGO coatings significantly (P < 0.05) enhanced the cellular viability for longer in vitro culture period (15 days) than control GO and pristine CpTi.

  6. Sodium functionalized graphene oxide coated titanium plates for improved corrosion resistance and cell viability

    Energy Technology Data Exchange (ETDEWEB)

    Marimuthu, Mohana [Department of Bionanotechnology, Gachon University, Seongnam Si, Gyeonggi-Do 461 701 (Korea, Republic of); Department of Engineering Physics, École Polytechnique de Montréal, Montreal, Quebec H3T 1J4 (Canada); Veerapandian, Murugan [Department of Bionanotechnology, Gachon University, Seongnam Si, Gyeonggi-Do 461 701 (Korea, Republic of); Department of Chemistry, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, Quebec H3C 3J7 (Canada); Ramasundaram, Subramaniyan; Hong, Seok Won [Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14 gil, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Sudhagar, P., E-mail: vedichi@gmail.com [Energy Materials Lab, WCU Program, Department of Energy Engineering, Hanyang University, Seoul 133 791 (Korea, Republic of); Nagarajan, Srinivasan [Energy Materials Lab, WCU Program, Department of Energy Engineering, Hanyang University, Seoul 133 791 (Korea, Republic of); Raman, V. [Department of Materials Science, Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi-shi, Ishikawa-ken 923-1292 (Japan); Ito, Eisuke [Flucto-Order Functions Research Team, RIKEN-ASI, Saitama 351-0198 (Japan); Kim, Sanghyo; Yun, Kyusik [Department of Bionanotechnology, Gachon University, Seongnam Si, Gyeonggi-Do 461 701 (Korea, Republic of); Kang, Yong Soo, E-mail: kangys@hanyang.ac.kr [Energy Materials Lab, WCU Program, Department of Energy Engineering, Hanyang University, Seoul 133 791 (Korea, Republic of)

    2014-02-28

    Surface functionalization is an important process that has been adopted to well explore the applications of nanomaterials. In this context, we demonstrate the sodium functionalized graphene oxide (NaGO) as an excellent candidate for increasing the life time of titanium (Ti) based ortho-implants. As-prepared aqueous dispersion of NaGO was used to assemble NaGO sheets on commercially pure Ti (CpTi) plates by heat controlled spin coating. The resulting wrinkled NaGO sheets play a dual role in implant material, i.e., passive layer against corrosion and biocompatible scaffold for cell viability. The preparation, physicochemical properties, and biocompatibility of NaGO coatings formed on CpTi were reported. The electrochemical polarization studies demonstrate the relative susceptibility of control GO and NaGO coatings to corrosion, which outline that the NaGO coating act as a geometric blocking layer and hence prevent the implant surface from contacting corrosive media. The immunofluorescence and cell proliferation studies performed using human dermal fibroblasts cells showed that NaGO coatings significantly (P < 0.05) enhanced the cellular viability for longer in vitro culture period (15 days) than control GO and pristine CpTi.

  7. Sodium functionalized graphene oxide coated titanium plates for improved corrosion resistance and cell viability

    Science.gov (United States)

    Marimuthu, Mohana; Veerapandian, Murugan; Ramasundaram, Subramaniyan; Hong, Seok Won; Sudhagar, P.; Nagarajan, Srinivasan; Raman, V.; Ito, Eisuke; Kim, Sanghyo; Yun, Kyusik; Kang, Yong Soo

    2014-02-01

    Surface functionalization is an important process that has been adopted to well explore the applications of nanomaterials. In this context, we demonstrate the sodium functionalized graphene oxide (NaGO) as an excellent candidate for increasing the life time of titanium (Ti) based ortho-implants. As-prepared aqueous dispersion of NaGO was used to assemble NaGO sheets on commercially pure Ti (CpTi) plates by heat controlled spin coating. The resulting wrinkled NaGO sheets play a dual role in implant material, i.e., passive layer against corrosion and biocompatible scaffold for cell viability. The preparation, physicochemical properties, and biocompatibility of NaGO coatings formed on CpTi were reported. The electrochemical polarization studies demonstrate the relative susceptibility of control GO and NaGO coatings to corrosion, which outline that the NaGO coating act as a geometric blocking layer and hence prevent the implant surface from contacting corrosive media. The immunofluorescence and cell proliferation studies performed using human dermal fibroblasts cells showed that NaGO coatings significantly (P enhanced the cellular viability for longer in vitro culture period (15 days) than control GO and pristine CpTi.

  8. High-temperature oxidation resistant (Cr, Al)N films synthesized using pulsed bias arc ion plating

    Science.gov (United States)

    Zhang, Min; Lin, Guoqiang; Lu, Guoying; Dong, Chuang; Kim, Kwang Ho

    2008-09-01

    (Cr, Al)N films were deposited by pulsed bias arc ion plating on HSS and 316L stainless steel substrates. With pulsed substrate bias ranging from -100 V to -500 V, the effect of pulsed bias on film composition, phase structure, deposition rate and mechanical properties was investigated by EDX, XRD, SEM, nanoindentation and scratch measurements. The high-temperature (up to 900 °C) oxidation resistance of the films was also evaluated. The results show that Al contents and deposition rates decrease with increasing pulsed bias and the ratio of (Cr + Al)/N is almost constant at 0.95. The as-deposited (Cr, Al)N films crystallize in the pseudo-binary (Cr, Al)N and Al phases. The film hardness increases with increasing bias and reaches the maximum 21.5 GPa at -500 V. The films deposited at -500 V exhibit a high adhesion force, about 70 N, and more interestingly good oxidation resistance when annealed in air at 900 °C for 10 h.

  9. Accurate timing of gamma rays with high-rate Resistive Plate Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, L. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal); Pereira, A. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal); Fonte, P. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal); Instituto Superior de Engenharia de Coimbra, 3030-199 Coimbra (Portugal); Ferreira Marques, R. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, 3004-516 Coimbra (Portugal) and Departamento de Fisica, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra, 3004-516 Coimbra (Portugal)]. E-mail: rui@lipc.fis.uc.pt

    2007-04-01

    The counting rate capability of RPCs is strongly conditioned by the availability of suitable resistive materials for the electrodes. For time-of-flight measurements in heavy-ion high-energy physics, the extension of the counting rate capabilities achievable with glass electrodes, around 2 kHz/cm{sup 2}, to much higher values is of fundamental importance. To address this issue we developed single-gap tRPCs with electrodes made from metal and from a commercially available ceramic material free of charge-depletion effects. Tests performed with 511 keV photons yielded a time resolution around 90 ps {sigma}. Neither the time resolution nor the efficiency have been affected by background rates of up to 20 kHz/cm{sup 2} produced with photons from an X-ray generator. The present result establishes the practical feasibility of accurate timing measurements with RPCs at rates up to 20 kHz/cm{sup 2}, while keeping a time resolution below 100 ps {sigma}.

  10. Accurate timing of gamma rays with high-rate Resistive Plate Chambers

    International Nuclear Information System (INIS)

    The counting rate capability of RPCs is strongly conditioned by the availability of suitable resistive materials for the electrodes. For time-of-flight measurements in heavy-ion high-energy physics, the extension of the counting rate capabilities achievable with glass electrodes, around 2 kHz/cm2, to much higher values is of fundamental importance. To address this issue we developed single-gap tRPCs with electrodes made from metal and from a commercially available ceramic material free of charge-depletion effects. Tests performed with 511 keV photons yielded a time resolution around 90 ps σ. Neither the time resolution nor the efficiency have been affected by background rates of up to 20 kHz/cm2 produced with photons from an X-ray generator. The present result establishes the practical feasibility of accurate timing measurements with RPCs at rates up to 20 kHz/cm2, while keeping a time resolution below 100 ps σ

  11. A Finite Element Analysis of Bearing Resistance of Timber Loaded through a Steel Plate

    Directory of Open Access Journals (Sweden)

    Leijten A.J.M.

    2012-01-01

    Full Text Available Decrease projected length of bolts due to bending deformation in timber joints compresses the steel washers onto timber member and increases lateral resistance of the joints. As this lateral strength increase primarily depend on bearing characteristics of timber beneath the steel washers, a finite element analysis was performed to predict their bearing-embedment behavior. A 3-D finite element model consisting of 8-node solid and contact pair elements was developed using ANSYS assuming an anisotropic plasticity model for timber and an elastic-perfectly plastic model for the washers. Material constants for both steel washer and timber member were obtained from previous test data. The results of the analysis were in good agreement with the experimental load-embedment curves as well as the analytical curves obtained in a previous study based on a rigid-body-spring-model. The same approach was also used to evaluate the effective bearing length (under uniform compression of a 50 mm depth timber block partially compressed.

  12. Performance of a resistive plate chamber equipped with a new prototype of amplified front-end electronics

    CERN Document Server

    Marchisone, Massimiliano

    2016-01-01

    ALICE is the LHC experiment dedicated to the study of heavy-ion collisions. At forward rapidity a muon spectrometer detects muons from low mass mesons, quarkonia, open heavy-flavor hadrons as well as weak bosons. A muon selection based on transverse momentum is made by a trigger system composed of 72 resistive plate chambers (RPCs). For the LHC Run 1 and the ongoing Run 2 the RPCs have been equipped with a non-amplified FEE called ADULT. However, in view of an increase in luminosity expected for Run 3 (2021-2023) the possibility to use an amplified FEE has been explored in order to improve the counting rate limitation and to prevent the aging of the detector, by reducing the charge per hit. A prototype of this new electronics (FEERIC) has been developed and tested first with cosmic rays before equipping one RPC in the ALICE cavern with it. In this talk the most important performance indicators - efficiency, dark current, dark rate, cluster size and total charge - of an RPC equipped with this new FEE will be r...

  13. Production of long-strip multi-gap resistive plate chamber module for the STAR-MTD system

    International Nuclear Information System (INIS)

    A new Long-strip Multi-gap Resistive Plate Chamber (LMRPC) prototype with 5 gas gaps has been developed for the Muon Telescope Detector (MTD) of the STAR experiment at RHIC in order to reduce the working High Voltage (HV) of previous design. Technical specifications related to the final infrastructure present in the experiment have motivated this effort. Its performance has been measured with cosmic rays. The efficiency of this prototype can reach 98% and the time resolution is around 95 ps. It shows a good uniformity among strips. The noise level is less than 0.2 Hz/cm2. The signal transmission and crosstalk of the modules was measured with a vector network analyzer, showing a good match with simulations within the amplifier bandwidth. A new cosmic-ray test system with long scintillators has been developed to accelerate the Quality Control (QC) process during the mass production of STAR-MTD. A selection of perpendicular cosmic-ray events for more accurate evaluation of the time resolution is achieved. The time resolution with this method is better, albeit with larger error, than the result obtained without any selection. A new spacer is used, resulting in a much reduced streamer ratio at comparable fields. Thirty-two modules have been built with the new spacer by the middle of April of 2012. They have been tested and they all have passed the QC.

  14. Neutron-detection efficiency of hybrid resistive plate chambers as estimated by using the MC50 cyclotron at KIRAMS

    International Nuclear Information System (INIS)

    We present the neutron-detection efficiencies of a Gd-coated single-gap resistive plate chamber (RPC) and a LiF-coated double-gap RPC. The experiments were performed by using indirect neutrons provided by the MC50 cyclotron at the Korea Institute of Radiological and Medical Science. Both RPCs show a decrease in the efficiency with increasing beam current, especially the Gd-coated RPC at the highest beam current (50 nA) that we received. Such a decrease in the efficiency could be understood in terms of a decrease in the effective electric field in the gas gap under high-particlerate environment. The operational plateaus start at about 8 kV for the Gd-coated RPC and at about 6.7 kV for the LiF-coated RPC. The neutron-detection efficiencies of the Gd-coated and the LiF-coated RPCs are about 2.5 and 1.8 %, respectively, at the operational high-voltage-plateau region. These results are completely consistent with the previous efficiencies obtained by using an intense 252Cf source.

  15. First GEANT4-based simulation investigation of a Li-coated resistive plate chamber for low-energy neutrons

    International Nuclear Information System (INIS)

    A simulation study of the performance of a single-gap resistive plate chamber coated with Li-layer for the detection of low energy neutrons was performed by means of GEANT4 Monte Carlo code. Low energy neutrons were detected via 7Li(n, α) 3He nuclear reaction. To make the detector sensitive to low energy neutrons, Li- coating was employed both on the forward and backward electrodes of the converter. Low energy neutrons were transported onto the Li-coating RPC by GEANT4 MC code. A detector with converter area of 5×5 cm2 was utilized for this work. The detection response was evaluated as a function of incident low energy neutrons in the range of 25 MeV–100 MeV. The evaluated results predicted higher detection response for the backward-coated converter detector than that of forward coated converter RPC setup. This type of detector can be useful for the detection of low energy neutrons

  16. First GEANT4-based simulation investigation of a Li-coated resistive plate chamber for low-energy neutrons

    Science.gov (United States)

    Rhee, J. T.; Jamil, M.; Jeon, Y. J.

    2013-08-01

    A simulation study of the performance of a single-gap resistive plate chamber coated with Li-layer for the detection of low energy neutrons was performed by means of GEANT4 Monte Carlo code. Low energy neutrons were detected via 7Li(n, α) 3He nuclear reaction. To make the detector sensitive to low energy neutrons, Li- coating was employed both on the forward and backward electrodes of the converter. Low energy neutrons were transported onto the Li-coating RPC by GEANT4 MC code. A detector with converter area of 5×5 cm2 was utilized for this work. The detection response was evaluated as a function of incident low energy neutrons in the range of 25 MeV-100 MeV. The evaluated results predicted higher detection response for the backward-coated converter detector than that of forward coated converter RPC setup. This type of detector can be useful for the detection of low energy neutrons.

  17. Current density and catalyst-coated membrane resistance distribution of hydro-formed metallic bipolar plate fuel cell short stack with 250 cm2 active area

    Science.gov (United States)

    Haase, S.; Moser, M.; Hirschfeld, J. A.; Jozwiak, K.

    2016-01-01

    An automotive fuel cell with an active area of 250 cm2 is investigated in a 4-cell short stack with a current and temperature distribution device next to the bipolar plate with 560 current and 140 temperature segments. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this current scan shunt module. The applied fuel cell consists of bipolar plates constructed of 75-μm-thick, welded stainless-steel foils and a graphitic coating. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this module with a 6% deviation in in-plane conductivity. The current density distribution is evaluated up to 2.4 A cm-2. The entire cell's investigated volumetric power density is 4.7 kW l-1, and its gravimetric power density is 4.3 kW kg-1 at an average cell voltage of 0.5 V. The current density distribution is determined without influencing the operating cell. In addition, the current density distribution in the catalyst-coated membrane and its effective resistivity distribution with a finite volume discretisation of Ohm's law are evaluated. The deviation between the current density distributions in the catalyst-coated membrane and the bipolar plate is determined.

  18. Effect of grain refinement and electrochemical nitridation on corrosion resistance of the 316L stainless steel for bipolar plates in PEMFCs environment

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Hongyun, Luo

    2015-10-01

    The stain-induced nanocrystalline α'-martensite was obtained by cryogenic cold rolling at liquid-nitrogen temperature for 316L stainless steel. The electrochemical results showed nanocrystalline 316L stainless steel deteriorated its corrosion resistance in a typical proton exchange membrane fuel cell environment compared with coarse grained one. However, comparing with electrochemically nitrided coarse grained stainless steel, electrochemically nitrided nanocrystalline stainless steel improved significantly corrosion resistance in the same environment, which was supported further by Mott-Shottky analysis. X-ray photoelectron spectroscopy analysis revealed that the nanocrystalline promoted the enrichment of nitrogen and chromium and inhibited form of NH3 on the surface, which could significantly improve the corrosion resistance of the 316L stainless steel. The present study showed that the electrochemically nitrided 316L stainless steel was more suitable for the bipolar plates in proton exchange membrane fuel cell environment than the untreated one, especially for nanocrystalline stainless steel.

  19. Characteristics of a double gap resistive plate chamber for the endcap region of CMS/LHC Data vs simulation in avalanche mode

    CERN Document Server

    Ahn, S H; Hong, B; Hong, S J; Kang, D H; Kang, T I; Kim, K H; Kim, T J; Kim, Y J; Kim, Y U; Koo, D G; Lee, H W; Lee, K S; Lee, S J; Lim, J K; Moon, D H; Nam, S K; Oh, J K; Park, S; Rhee, J T; Ryu, M S; Sim, K S

    2004-01-01

    We present the detailed analysis of the time and charge signals of a prototype double gap resistive plate chamber for the endcap region of the compact muon solenoid detector at CERN LHC. We demonstrate that the operating high-voltage plateau can be extended at least up to 400 V with the present design. The simple avalanche multiplication model can reproduce the experimental charge spectra reasonably well at the beginning of the high-voltage plateau region. The effective Townsend coefficient is estimated in the avalanche mode operation.

  20. Corrosion resistance of siloxane–poly(methyl methacrylate) hybrid films modified with acetic acid on tin plate substrates: Influence of tetraethoxysilane addition

    International Nuclear Information System (INIS)

    Highlights: • Siloxane–PMMA film was produced by dip-coating on tin plate substrate. • It was evaluated the influence of (TEOS) addition on siloxane–PMMA hybrid films. • Siloxane–PMMA films without TEOS presented a regular coverage and lowest roughness. • The TEOS addition decrease the corrosion resistance of siloxane–PMMA films. • Siloxane–PMMA without TEOS presented is higher durability in the film wear test. - Abstract: The aim of this paper is to study the corrosion resistance of hybrid films. Tin plate was coated with a siloxane–poly (methyl methacrylate) (PMMA) hybrid film prepared by sol–gel route with covalent bonds between the organic (PMMA) and inorganic (siloxane) phases obtained by hydrolysis and polycondensation of 3-(trimethoxysilylpropyl) methacrylate (TMSM) and polymerization of methyl methacrylate (MMA) using benzoyl peroxide (BPO) as a thermic initiator. Hydrolysis reactions were catalyzed by acetic acid solution avoiding the use of chlorine or stronger acids in the film preparation. The effect of the addition of tetraethoxysilane (TEOS) on the protective properties of the film was evaluated. The hydrophobicity of the film was determined by contact angle measurements, and the morphology was evaluated by scanning electron microscopy (SEM) and profilometry. The local nanostructure was investigated by Fourier transform infrared spectroscopy (FT-IR). The electrochemical behavior of the films was assessed by open circuit potential monitoring, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 M NaCl solution. The mechanical behavior was evaluated by tribology. The results highlighted that the siloxane–PMMA hybrid films modified with acetic acid are promising anti-corrosive coatings that acts as an efficient diffusion barrier, protecting tin plates against corrosion. However, the coating properties were affected by the TEOS addition, which contributed for the thickness increase

  1. Corrosion resistance of siloxane–poly(methyl methacrylate) hybrid films modified with acetic acid on tin plate substrates: Influence of tetraethoxysilane addition

    Energy Technology Data Exchange (ETDEWEB)

    Kunst, S.R.; Cardoso, H.R.P. [LAPEC, Federal University of Rio Grande do Sul – UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, RS (Brazil); Oliveira, C.T. [ICET, University Feevale, RS-239, 2755 Novo Hamburgo, RS (Brazil); Santana, J.A.; Sarmento, V.H.V. [Department of Chemistry, Federal University of Sergipe – UFS, Av. Vereador Olímpio Grande s/n, Centro, Itabaiana, SE (Brazil); Muller, I.L. [LAPEC, Federal University of Rio Grande do Sul – UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, RS (Brazil); Malfatti, C.F., E-mail: celia.malfatti@ufrgs.br [LAPEC, Federal University of Rio Grande do Sul – UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, RS (Brazil)

    2014-04-01

    Highlights: • Siloxane–PMMA film was produced by dip-coating on tin plate substrate. • It was evaluated the influence of (TEOS) addition on siloxane–PMMA hybrid films. • Siloxane–PMMA films without TEOS presented a regular coverage and lowest roughness. • The TEOS addition decrease the corrosion resistance of siloxane–PMMA films. • Siloxane–PMMA without TEOS presented is higher durability in the film wear test. - Abstract: The aim of this paper is to study the corrosion resistance of hybrid films. Tin plate was coated with a siloxane–poly (methyl methacrylate) (PMMA) hybrid film prepared by sol–gel route with covalent bonds between the organic (PMMA) and inorganic (siloxane) phases obtained by hydrolysis and polycondensation of 3-(trimethoxysilylpropyl) methacrylate (TMSM) and polymerization of methyl methacrylate (MMA) using benzoyl peroxide (BPO) as a thermic initiator. Hydrolysis reactions were catalyzed by acetic acid solution avoiding the use of chlorine or stronger acids in the film preparation. The effect of the addition of tetraethoxysilane (TEOS) on the protective properties of the film was evaluated. The hydrophobicity of the film was determined by contact angle measurements, and the morphology was evaluated by scanning electron microscopy (SEM) and profilometry. The local nanostructure was investigated by Fourier transform infrared spectroscopy (FT-IR). The electrochemical behavior of the films was assessed by open circuit potential monitoring, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 M NaCl solution. The mechanical behavior was evaluated by tribology. The results highlighted that the siloxane–PMMA hybrid films modified with acetic acid are promising anti-corrosive coatings that acts as an efficient diffusion barrier, protecting tin plates against corrosion. However, the coating properties were affected by the TEOS addition, which contributed for the thickness increase

  2. Preparation of corrosion-resistant and conductive trivalent Cr-C coatings on 304 stainless steel for use as bipolar plates in proton exchange membrane fuel cells by electrodeposition

    Science.gov (United States)

    Wang, Hsiang-Cheng; Sheu, Hung-Hua; Lu, Chen-En; Hou, Kung-Hsu; Ger, Ming-Der

    2015-10-01

    In this study, Cr-C-coated bipolar plates are produced by electroplating on the SS304 plates with a machined flow channel. The resulting plates were tested using potentiodynamic and potentiostatic measurements in simulated PEMFC environments, which show that the bipolar plate coated with Cr-C exhibited good anticorrosion performance. The corrosive current density of the Cr-C coating formed for a plating time of 10 min for 10 h exhibits a low stable value of 1.51 × 10-10 A/cm2 during the potentiostatic test in a 0.5 M H2SO4 + 2 ppm HF solution at 70 °C with an air purge, indicating that the Cr-C coating plated for 10 min is stable in a cathode environment. The interfacial contact resistance (ICR) of the bipolar plate with the Cr-C coating clearly improved, presenting an ICR of 19.52 mΩ cm2 at a pressure of 138 N/cm2. The results from scanning electron microscopy (SEM) and ICR before and after the corrosion tests indicate that the bipolar plate with the Cr-C coating is electrochemically stable. In this study, the maximum power density (212.41 mW/cm2) is obtained at a cell temperature of 80 °C and a gas flow rate of 300 standard cubic centimeters per minute (sccm) when Cr-C coated SS304 bipolar plates were used.

  3. Research on the Corrosion Resistance of R60702 Tube Plate Angle Joint%R60702管板角接接头耐蚀性研究

    Institute of Scientific and Technical Information of China (English)

    张莹莹; 纪强; 王国嘉

    2014-01-01

    工业纯锆R60702是一种稀有金属,具有良好的焊接性和抗腐蚀性,其熔点、硬度和强度均很高。分析了 R60702在经过管板角接后,焊缝的元素成分和耐腐蚀性能,通过极化曲线和交流阻抗图分别表征了锆材焊缝在30℃和70℃的耐蚀性。%Industrial pure zirconium R60702 is a rare metal, has good weld ability and corrosion resistance, and its melting point, hardness and strength are very high. In this paper, element composition and corrosion resistance of zirconium R60702 weld seam after tube plate angle joint were analyzed. Through the polarization curve and AC impedance graph respectively characterize the corrosion resistance of the zirconium weld joint at 30℃and 70℃.

  4. Investigation of the effects of process sequence on the contact resistance characteristics of coated metallic bipolar plates for polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Turan, Cabir; Cora, Ömer Necati; Koç, Muammer

    2013-12-01

    In this study, results of an investigation on the effects of manufacturing and coating process sequence on the contact resistance (ICR) of metallic bipolar plates (BPP) for polymer electrolyte membrane fuel cells (PEMFCs) are presented. Firstly, uncoated stainless steel 316L blanks were formed into BPP through hydroforming and stamping processes. Then, these formed BPP samples were coated with three different PVD coatings (CrN, TiN and ZrN) at three different thicknesses (0.1, 0.5 and 1 μm). Secondly, blanks of the same alloy were coated first with the same coatings, thickness and technique; then, they were formed into BPPs of the same shape and dimensions using the manufacturing methods as in the first group. Finally, these two groups of BPP samples were tested for their ICR to reveal the effect of process sequence. ICR tests were also conducted on the BPP plates both before and after exposure to corrosion to disclose the effect of corrosion on ICR. Coated-then-formed BPP samples exhibited similar or even better ICR performance than formed-then-coated BPP samples. Thus, manufacturing of coated blanks can be concluded to be more favorable and worth further investigation in quest of making cost effective BPPs for mass production of PEMFC.

  5. Effect of Initial Crack Location on Spatial Randomness of Fatigue Crack Growth Resistance in Friction Stir Welded AA7075-T651 Plates

    International Nuclear Information System (INIS)

    In the present paper, the effects of initial crack location on spatial randomness of fatigue crack growth resistance (FCGR) in friction stir welded (FSWed) AA7075-T651 plates were studied. The objective of this study is to characterize the statistical properties of FCGR for three different types of initial crack location (ICL) specimens. In this work, the FCGR coefficients were treated as a spatial random process. It was found that the FCGR coefficients for all initial crack location specimens closely followed a two parameter Weibull distribution. The shape parameter of the Weibull distribution for BM-ICL specimens showed the largest value of 7.50, and that for the WM-ICL specimens showed the smallest value of 2.61. In addition, the autocorrelation functions for all the ICL specimens followed the exponential function

  6. Measurement of drift velocity and amplification coefficient in C2H2F4-Isobutane mixtures for avalanche operated Resistive Plate Counters

    CERN Document Server

    Colucci, A; Grancagnolo, F; Primavera, M

    1998-01-01

    The knowledge of the transport and amplification parameters (drift velocity, first Townsend and attachment coefficients) of the gas mixtures used for avalanche operated Resistive Plate Counters gives the possibility ofbetter understanding the underlying physical processes of these detectors and of developping Montecarlo simulations of their behaviour.We present here a measurement of the drift velocity $v_{d}$and of the amplification coefficient $\\eta$ in $C_{2}H_{2}F_{4}$-Isobutanemixtures. The ionization in the gas, contained in a 6$\\times$22~cm$^2$, 2~mm gap RPC, is obtained by means of a pulsed $N_{2}$ laser,via double photon ionization. Results are presented for $v_{d}$ and $\\eta$ as a function of the applied electric field.

  7. Measurement of drift velocity and amplification coefficient in C sub 2 H sub 2 F sub 4 -isobutane mixtures for avalanche-operated resistive-plate counters

    CERN Document Server

    Colucci, A; Grancagnolo, F; Primavera, M

    1999-01-01

    The knowledge of the transport and amplification parameters (drift velocity, first Townsend and attachment coefficients) of the gas mixtures used for avalanche-operated resistive-plate counters gives the possibility of better understanding the underlying physical processes of these detectors and of developing Montecarlo simulations of their behaviour. We present here a measurement of the drift velocity v sub d and of the amplification coefficient eta in C sub 2 H sub 2 F sub 4 -isobutane mixtures. The ionization in the gas, contained in a 6x22 cm sup 2 , 2 mm gap RPC, is obtained by means of a pulsed N sub 2 laser, via double-photon ionization. Results are presented for v sub d and eta as a function of the applied electric field.

  8. Effect of Initial Crack Location on Spatial Randomness of Fatigue Crack Growth Resistance in Friction Stir Welded AA7075-T651 Plates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seon Jin [Pukyong National University, Busan (Korea, Republic of)

    2014-09-15

    In the present paper, the effects of initial crack location on spatial randomness of fatigue crack growth resistance (FCGR) in friction stir welded (FSWed) AA7075-T651 plates were studied. The objective of this study is to characterize the statistical properties of FCGR for three different types of initial crack location (ICL) specimens. In this work, the FCGR coefficients were treated as a spatial random process. It was found that the FCGR coefficients for all initial crack location specimens closely followed a two parameter Weibull distribution. The shape parameter of the Weibull distribution for BM-ICL specimens showed the largest value of 7.50, and that for the WM-ICL specimens showed the smallest value of 2.61. In addition, the autocorrelation functions for all the ICL specimens followed the exponential function.

  9. Simulation and prototyping of 2 m long resistive plate chambers for detection of fast neutrons and multi-neutron event identification

    Energy Technology Data Exchange (ETDEWEB)

    Elekes, Z., E-mail: z.elekes@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Aumann, T. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Technische Universität Darmstadt, Darmstadt (Germany); Bemmerer, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Boretzky, K. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Caesar, C. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Technische Universität Darmstadt, Darmstadt (Germany); Cowan, T.C. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Hehner, J.; Heil, M. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Kempe, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Rossi, D. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Röder, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Simon, H. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Sobiella, M.; Stach, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Reinhardt, T. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Wagner, A.; Yakorev, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Zilges, A. [Universität zu Köln, Köln (Germany); Zuber, K. [Technische Universität Dresden, Dresden (Germany)

    2013-02-11

    Resistive plate chamber (RPC) prototypes of 2 m length were simulated and built. The experimental tests using a 31 MeV electron beam, discussed in details, showed an efficiency higher than 90% and an excellent time resolution of around σ=100ps. Furthermore, comprehensive simulations were performed by GEANT4 toolkit in order to study the possible use of these RPCs for fast neutron (200 MeV–1 GeV) detection and multi-neutron event identification. The validation of simulation parameters was carried out via a comparison to experimental data. A possible setup for invariant mass spectroscopy of multi-neutron emission is presented and the characteristics are discussed. The results show that the setup has a high detection efficiency. Its capability of determining the momentum of the outgoing neutrons and reconstructing the relative energy between the fragments from nuclear reactions is demonstrated for different scenarios.

  10. Simulation and prototyping of 2 m long resistive plate chambers for detection of fast neutrons and multi-neutron event identification

    International Nuclear Information System (INIS)

    Resistive plate chamber (RPC) prototypes of 2 m length were simulated and built. The experimental tests using a 31 MeV electron beam, discussed in details, showed an efficiency higher than 90% and an excellent time resolution of around σ=100ps. Furthermore, comprehensive simulations were performed by GEANT4 toolkit in order to study the possible use of these RPCs for fast neutron (200 MeV–1 GeV) detection and multi-neutron event identification. The validation of simulation parameters was carried out via a comparison to experimental data. A possible setup for invariant mass spectroscopy of multi-neutron emission is presented and the characteristics are discussed. The results show that the setup has a high detection efficiency. Its capability of determining the momentum of the outgoing neutrons and reconstructing the relative energy between the fragments from nuclear reactions is demonstrated for different scenarios.

  11. Electroless plating of low-resistivity Cu–Mn alloy thin films with self-forming capacity and enhanced thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Sung-Te, E-mail: stchen@mail.hust.edu.tw [Department of Electronic Engineering, Hsiuping University of Science and Technology, Dali 412, Taichung, Taiwan (China); Chen, Giin-Shan [Department of Materials Science and Engineering, Feng Chia University, Seatwen 407, Taichung, Taiwan (China)

    2015-11-05

    Previous studies have typically used sputter deposition to fabricate Cu–Mn alloy thin films with concentrated solute additions which have exceeded several atomic percentages, and the electrical resistivity values of the resultant films from previous studies are relatively high, ranging from 2.5 to 3.5 μΩ-cm. Herein, we proposed a different approach by using electroless process to plate dilute Cu–Mn (0.1 at.%) alloy thin films on dielectric layers (SiO{sub 2}). Upon forming-gas annealing, the Mn incorporated into Cu–Mn films was segregated toward the SiO{sub 2} side, eventually converting itself into a few atomic layer thickness at the Cu/SiO{sub 2} interface, and forming films with a low level of resistivity the same as that of pure Cu films (2.0 μΩ-cm). The interfacial layer served as not only a diffusion barrier, but also an adhesion promoter that prevented the film’s agglomeration during annealing at elevated temperatures. The mechanism for the dual-function performance by the Mn addition was elucidated by interfacial bonding analysis, as well as dynamic (adhesive strength) and thermodynamic (surface-tension) measurements. - Highlights: • Electroless plating is proposed to grow dilute (0.1%) Cu–Mn films on SiO{sub 2} layers. • Adequate annealing results in a self-forming of MnO{sub x} at the Cu/SiO{sub 2} interface. • The role of interfacial MnO{sub x} as a barrier and adhesion promoter is demonstrated. • The treated dilute film has a low ρ level of pure Cu, in contrast to concentrated films. • Its potential as a single entity replacement of Cu interconnect is presented.

  12. Cyclotriphosphazene and TiO2 reinforced nanocomposite coated on mild steel plates for antibacterial and corrosion resistance applications

    Science.gov (United States)

    Krishnadevi, Krishnamoorthy; Selvaraj, Vaithilingam

    2016-03-01

    The mild steel surface has been modified to impart anticorrosion and antibacterial properties through a dip coating method followed by thermal curing of a mixture containing amine terminated cyclotriphosphazene and functionalized titanium dioxide nanoparticles reinforced benzoxazine based cyanate ester composite (ATCP/FTiO2/Bz-CE). The corrosion resistance behavior of coating material has been investigated by electrochemical and antibacterial studies by disc diffusion method. The nanocomposites coated mild steels have displayed a good chemical stability over long immersion in a corrosive environment. The protection efficiency has found to be high for ATCP/FTiO2/Bz-CE composites, which can be used in microelectronics and marine applications.

  13. Histologia da pele da carpa prateada (Hypophtalmichthys molitrix e testes de resistência do couro Histology of silver-plated carp skin (Hypophtalmichthys molitrix and leather resistance tests

    Directory of Open Access Journals (Sweden)

    Maria Luiza Rodrigues de Souza

    2006-08-01

    Full Text Available Este estudo foi realizado com os objetivos de analisar a histologia da pele e avaliar a influência da técnica de curtimento e da posição da retirada do corpo-de-prova sobre a qualidade da pele de carpa prateada (Hypophtalmichthys molitrix. Vinte e três peixes foram insensibilizados para retirada das peles para curtimento. Amostras referentes a três peixes foram fixadas em formol 10%. Após a inclusão em parafina, foram cortadas com aproximadamente 5 mm de espessura e coradas pela técnica de hematoxilina-eosina (HE. Após o curtimento das peles, foram retirados os corpos-de-prova para os testes de resistência. Os testes foram realizados com dinamômetro EMIC, com velocidade de afastamento entre cargas de 100 ± 20 mm/mm, em ambiente climatizado a 23ºC e umidade relativa do ar de 50% por um período de 24 horas. As peles curtidas com sais de cromo apresentaram maior resistência à tração (16,96 N/mm², ao alongamento (51,49% e ao rasgamento progressivo (16,75 N/mm quando comparadas àquelas curtidas sem sais de cromo (tração = 9,12 N/mm², alongamento = 17,48% e rasgamento = 11,36 N/mm. O sentido da retirada dos corpos-de-prova não interferiu nas características de tração, elongação, carga de ruptura, rasgo, força máxima e carga de força. A técnica de curtimento (utilizando ou não sais de cromo influencia a resistência das peles de carpa prateada. A técnica empregando os sais de cromo proporciona maior resistência ao couro.The objectives of this trial were to analyze the skin histology and to evaluate the influence of tanning technique and the direction removal of samples on skin quality of silver-plated carp (Hypophtalmichthys molitrix. Twenty-three fishes were sacrificed and the skin was removed for tanning. Samples of three fishes were settled in formol 10% and, after inclusion in paraffin, the samples were cut with approximately 5 mm of thickness and colored by the hematoxylin-eosin technique (HE. After skin

  14. 机械镀锌镀层钝化与耐蚀性能研究%PASSIVATION AND CORROSION RESISTANCE OF MECHANICALLY PLATED ZINC COATING

    Institute of Scientific and Technical Information of China (English)

    赵增典; 黄保雷; 陈磊; 李德刚

    2009-01-01

    对机械镀锌层分别用三价铬、稀土和六价铬进行了钝化处理,利用盐雾试验和电化学测试对不同钝化膜的耐蚀性与电化学行为进行了比较研究.盐雾试验结果表明,稀土与三价铬钝化处理的效果均已超过传统的六价铬钝化,比六价铬钝化膜的耐蚀性提高了一倍以上;稀土钝化膜的耐蚀性最好,三价铬钝化膜的耐蚀性仅次于稀土钝化膜的.电化学测试表明,三价铬、稀土和六价铬钝化膜都能够不同程度地抑制腐蚀的阴极电极反应,抑制阴极反应程度最大的是稀土钝化膜,其次是三价铬钝化膜,最小的是六价铬钝化膜.三价铬与稀土钝化工艺的环保和良好的防腐效果使其具有良好的应用前景.%The mechanically plated zinc coating was passivated with chemicals containing trivalent chromi-um,rare earth metal and hexavalent chromium respectively.Then the corrosion resistance and electrochemi-cal behavior of the passivated coatings were compared by salt spay test and electrochemical test.The result of salt spay test showed that the coatings passivated with trivalent chromium and rare earth metal are superi-or to that with hexavalent chromium by one fold in corrosion resistance.The coating passivated with rare earth metal Was the best in corrosion resistance and that with trivalent chromium was the next.The electro-chemical test showed that all the passivation treatments with trivalent chromium,rare earth metal and hexa-valent chromium could suppress the cathode reactions to some extent.The effectiveness of passivation chem-icals in suppression of the cathodic reaction might be ranking as follows:rare earth metal,trivalent chromi-um.and hexavalent chromiam.Therefore,chemicals containing trivalent chromiam and rare earth metal had good application foreground for their good corrosion resistance and environmental-friendly.

  15. Large-scale performance studies of the Resistive Plate Chamber fast tracker for the ATLAS 1st-level muon trigger

    CERN Document Server

    Cattani, G; The ATLAS collaboration

    2009-01-01

    In the ATLAS experiment, Resistive Plate Chambers provide the first-level muon trigger and bunch crossing identification over large area of the barrel region, as well as being used as a very fast 2D tracker. To achieve these goals a system of about ~4000 gas gaps operating in avalanche mode was built (resulting in a total readout surface of about 16000 m2 segmented into 350000 strips) and is now fully operational in the ATLAS pit, where its functionality has been widely tested up to now using cosmic rays. Such a large scale system allows to study the performance of RPCs (both from the point of view of gas gaps and readout electronics) with unprecedented sensitivity to rare effects, as well as providing the means to correlate (in a statistically significant way) characteristics at production sites with performance during operation. Calibrating such a system means fine tuning thousands of parameters (involving both front-end electronics and gap voltage), as well as constantly monitoring performance and environm...

  16. Maximization of the acceptance and momentum resolution of the ATLAS muon spectrometer with novel drift-tube and resistive plate chambers

    CERN Document Server

    Schwegler, Philipp; The ATLAS collaboration

    2014-01-01

    The ATLAS muon spectrometer provides high momentum resolution up to transverse muon momenta in the TeV range in almost the full pseudo-rapidity interval of −2.7 < η < 2.7. The acceptance of the muon spectrometer is currently limited by uninstrumented regions in the vicinity of η = 0 to provide space for cables and services of the inner detector and the calorimeters and in the feet region due to space limitations. A large fraction of these acceptance gaps will successively be closed by installing novel small monitored drift tube (sMDT) chambers with tubes of half the diameter of the present MDT chambers and novel resistive plate chambers (RPC) with smaller gas gaps and higher spatial resolution. The reduced size of the chambers without loss of measurement points does not only make it possible to equip the originally uninstrumented regions with tracking and trigger chambers, but also to operate the new chambers under the highly increased background radiation levels expected for the operation of the mu...

  17. Thermal conductivity of a graphite bipolar plate (BPP) and its thermal contact resistance with fuel cell gas diffusion layers: Effect of compression, PTFE, micro porous layer (MPL), BPP out-of-flatness and cyclic load

    Science.gov (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid

    2015-01-01

    This paper reports on measurements of thermal conductivity of a graphite bipolar plate (BPP) as a function of temperature and its thermal contact resistance (TCR) with treated and untreated gas diffusion layers (GDLs). The thermal conductivity of the BPP decreases with temperature and its thermal contact resistance with GDLs, which has been overlooked in the literature, is found to be dominant over a relatively wide range of compression. The effects of PTFE loading, micro porous layer (MPL), compression, and BPP out-of-flatness are also investigated experimentally. It is found that high PTFE loadings, MPL and even small BPP out-of-flatness increase the BPP-GDL thermal contact resistance dramatically. The paper also presents the effect of cyclic load on the total resistance of a GDL-BPP assembly, which sheds light on the behavior of these materials under operating conditions in polymer electrolyte membrane fuel cells.

  18. Optimization of a closed-loop gas system for the operation of Resistive Plate Chambers at the Large Hadron Collider experiments

    Science.gov (United States)

    Capeans, M.; Glushkov, I.; Guida, R.; Hahn, F.; Haider, S.

    2012-01-01

    Resistive Plate Chambers (RPCs), thanks to their fast time resolution (˜1 ns), suitable space resolution (˜1 cm) and low production cost (˜50 €/m2), are widely employed for the muon trigger systems at the Large Hadron Collider (LHC). Their large detector volume (they cover a surface of about 4000 m2 equivalent to 16 m3 of gas volume both in ATLAS and CMS) and the use of a relatively expensive Freon-based gas mixture make a closed-loop gas circulation unavoidable. It has been observed that the return gas of RPCs operated in conditions similar to the difficult experimental background foreseen at LHC contains a large amount of impurities potentially dangerous for long-term operation. Several gas-cleaning agents are currently in use in order to avoid accumulation of impurities in the closed-loop circuits. We present the results of a systematic study characterizing each of these cleaning agents. During the test, several RPCs were operated at the CERN Gamma Irradiation Facility (GIF) in a high radiation environment in order to observe the production of typical impurities: mainly fluoride ions, molecules of the Freon group and hydrocarbons. The polluted return gas was sent to several cartridges, each containing a different cleaning agent. The effectiveness of each material was studied using gas chromatography and mass-spectrometry techniques. Results of this test have revealed an optimized configuration of filters that is now under long-term validation.Gas optimization studies are complemented with a finite element simulation of gas flow distribution in the RPCs, aiming at its eventual optimization in terms of distribution and flow rate.

  19. Optimization of a closed-loop gas system for the operation of Resistive Plate Chambers at the Large Hadron Collider experiments

    International Nuclear Information System (INIS)

    Resistive Plate Chambers (RPCs), thanks to their fast time resolution (∼1 ns), suitable space resolution (∼1 cm) and low production cost (∼50 €/m2), are widely employed for the muon trigger systems at the Large Hadron Collider (LHC). Their large detector volume (they cover a surface of about 4000 m2 equivalent to 16 m3 of gas volume both in ATLAS and CMS) and the use of a relatively expensive Freon-based gas mixture make a closed-loop gas circulation unavoidable. It has been observed that the return gas of RPCs operated in conditions similar to the difficult experimental background foreseen at LHC contains a large amount of impurities potentially dangerous for long-term operation. Several gas-cleaning agents are currently in use in order to avoid accumulation of impurities in the closed-loop circuits. We present the results of a systematic study characterizing each of these cleaning agents. During the test, several RPCs were operated at the CERN Gamma Irradiation Facility (GIF) in a high radiation environment in order to observe the production of typical impurities: mainly fluoride ions, molecules of the Freon group and hydrocarbons. The polluted return gas was sent to several cartridges, each containing a different cleaning agent. The effectiveness of each material was studied using gas chromatography and mass-spectrometry techniques. Results of this test have revealed an optimized configuration of filters that is now under long-term validation. Gas optimization studies are complemented with a finite element simulation of gas flow distribution in the RPCs, aiming at its eventual optimization in terms of distribution and flow rate.

  20. Joint measurement of the atmospheric muon flux through the Puy de Dôme volcano with plastic scintillators and Resistive Plate Chambers detectors

    Science.gov (United States)

    Ambrosino, F.; Anastasio, A.; Bross, A.; Béné, S.; Boivin, P.; Bonechi, L.; Cârloganu, C.; Ciaranfi, R.; Cimmino, L.; Combaret, Ch.; D'Alessandro, R.; Durand, S.; Fehr, F.; Français, V.; Garufi, F.; Gailler, L.; Labazuy, Ph.; Laktineh, I.; Lénat, J.-F.; Masone, V.; Miallier, D.; Mirabito, L.; Morel, L.; Mori, N.; Niess, V.; Noli, P.; Pla-Dalmau, A.; Portal, A.; Rubinov, P.; Saracino, G.; Scarlini, E.; Strolin, P.; Vulpescu, B.

    2015-11-01

    The muographic imaging of volcanoes relies on the measured transmittance of the atmospheric muon flux through the target. An important bias affecting the result comes from background contamination mimicking a higher transmittance. The MU-RAY and TOMUVOL collaborations measured independently in 2013 the atmospheric muon flux transmitted through the Puy de Dôme volcano using their early prototype detectors, based on plastic scintillators and on Glass Resistive Plate Chambers, respectively. These detectors had three (MU-RAY) or four (TOMUVOL) detection layers of 1 m2 each, tens (MU-RAY) or hundreds (TOMUVOL) of nanosecond time resolution, a few millimeter position resolution, an energy threshold of few hundreds MeV, and no particle identification capabilities. The prototypes were deployed about 1.3 km away from the summit, where they measured, behind rock depths larger than 1000 m, remnant fluxes of 1.83±0.50(syst)±0.07(stat) m-2 d-1 deg-2 (MU-RAY) and 1.95±0.16(syst)±0.05(stat) m-2 d-1 deg-2 (TOMUVOL), that roughly correspond to the expected flux of high-energy atmospheric muons crossing 600 meters water equivalent (mwe) at 18° elevation. This implies that imaging depths larger than 500 mwe from 1 km away using such prototype detectors suffer from an overwhelming background. These measurements confirm that a new generation of detectors with higher momentum threshold, time-of-flight measurement, and/or particle identification is needed. The MU-RAY and TOMUVOL collaborations expect shortly to operate improved detectors, suitable for a robust muographic imaging of kilometer-scale volcanoes.

  1. Bipolar battery plate

    Science.gov (United States)

    Rowlette, John J. (Inventor)

    1987-01-01

    A liquid-impermeable plate (10) having through-plate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with led spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  2. Plate tectonics

    Digital Repository Service at National Institute of Oceanography (India)

    Chaubey, A.K.

    and ocean floor lie. The plates are in continuous motion at a speed of few centimeters per year over the asthenosphere, which is highly viscous, easily deformable layer between upper and lower mantle. The relative motion between the plates produces new... the newly generated magma, the solidified part of the older magma moves away from the ridge axes. This process is known as seafloor spreading. At subduction zones the old oceanic lithosphere is consumed in the asthenosphere to accommodate the newly...

  3. Preparation of a photo-degradation- resistant quantum dot-polymer composite plate for use in the fabrication of a high-stability white-light-emitting diode

    Science.gov (United States)

    Jang, Eun-Pyo; Song, Woo-Seuk; Lee, Ki-Heon; Yang, Heesun

    2013-02-01

    We report on the synthesis of highly fluorescent double-ZnS-shell-capped, yellow-emitting Cu-In-S quantum dots (QDs) with a surprisingly high quantum yield of 92%, the preparation of a free-standing QD-polymethylmethacrylate composite plate, and the application of the QD plate in the fabrication of QD-based white-light-emitting diodes (WLEDs). A free-standing QD plate with QDs embedded uniformly inside a polymeric matrix is used to fabricate a remote-type, resin-free WLED. The QD plate-based WLED displays a high luminous efficiency; however, it suffers from a significantly unstable device performance due to QD degradation upon prolonged photo-excitation. An exceptional operational stability of the QD plate-based WLED is realized by generating hybrid double layers of an organic adhesion layer and a gas barrier layer of sol-gel-derived silica, rendering the QD plate impermeable to oxygen. Our success in achieving a color converter robust against photo-degradation and applying it in the fabrication of a reliable QD-based LED is greatly encouraging as regards the development of next-generation QD-based LED lighting sources.

  4. Preparation of a photo-degradation- resistant quantum dot-polymer composite plate for use in the fabrication of a high-stability white-light-emitting diode.

    Science.gov (United States)

    Jang, Eun-Pyo; Song, Woo-Seuk; Lee, Ki-Heon; Yang, Heesun

    2013-02-01

    We report on the synthesis of highly fluorescent double-ZnS-shell-capped, yellow-emitting Cu-In-S quantum dots (QDs) with a surprisingly high quantum yield of 92%, the preparation of a free-standing QD-polymethylmethacrylate composite plate, and the application of the QD plate in the fabrication of QD-based white-light-emitting diodes (WLEDs). A free-standing QD plate with QDs embedded uniformly inside a polymeric matrix is used to fabricate a remote-type, resin-free WLED. The QD plate-based WLED displays a high luminous efficiency; however, it suffers from a significantly unstable device performance due to QD degradation upon prolonged photo-excitation. An exceptional operational stability of the QD plate-based WLED is realized by generating hybrid double layers of an organic adhesion layer and a gas barrier layer of sol-gel-derived silica, rendering the QD plate impermeable to oxygen. Our success in achieving a color converter robust against photo-degradation and applying it in the fabrication of a reliable QD-based LED is greatly encouraging as regards the development of next-generation QD-based LED lighting sources. PMID:23299514

  5. Plain carbon steel bipolar plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    WANG Jianli; SUN Juncai; TIAN Rujin; XU Jing

    2006-01-01

    Bipolar plates are a multifunctional component of PEMFC. Comparing with the machined graphite and stainless steels, the plain carbon steel is a very cheap commercial metal material. In this paper, the possibility of applying the plain carbon steels in the bipolar plate for PEMFC was exploited. In order to improve the corrosion resistance of the low carbon steel in the PEMFCs' environments,two surface modification processes was developed and then the electrochemical performances and interfacial contact resistance (ICR) of the surface modified plate of plain carbon steel were investigated. The results show that the surface modified steel plates have good corrosion resistance and relatively low contact resistance, and it may be a candidate material as bipolar plate of PEMFC.

  6. Dynamics of Tectonic Plates

    CERN Document Server

    Pechersky, E; Sadowski, G; Yambartsev, A

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend on features of resistant forces.

  7. Methicillin-resistant Staphylococcus aureus infected pseudo-arthrosis of the distal tibia treated with debridement, mesh cage, autologous grafting and locking plate fixation

    OpenAIRE

    Motsitsi, Silas N. S.

    2008-01-01

    Infected non-union of long bones is a challenge to manage. It has a high morbidity and mortality. Treatment is very demanding and has a significant complication rate. Methicillin-resistant infected non-union has a higher morbidity and mortality compared to Methicillin-sensitive Staphylococcus aureus infection. Approximately half of all Staphylococci isolated in infected orthopaedic operations are caused by Methicillin-resistant S. aureus. We present a 42-year-old patient who had Methicillin-r...

  8. Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

    Science.gov (United States)

    Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

    2016-04-01

    This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

  9. Indonesian Landforms and Plate Tectonics

    Directory of Open Access Journals (Sweden)

    Herman Th. Verstappen

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v5i3.103The horizontal configuration and vertical dimension of the landforms occurring in the tectonically unstable parts of Indonesia were resulted in the first place from plate tectonics. Most of them date from the Quaternary and endogenous forces are ongoing. Three major plates – the northward moving Indo-Australian Plate, the south-eastward moving SE-Asian Plate and the westward moving Pacific Plate - meet at a plate triple-junction situated in the south of New Guinea’s Bird’s Head. The narrow North-Moluccan plate is interposed between the Asia and Pacific. It tapers out northward in the Philippine Mobile Belt and is gradually disappearing. The greatest relief amplitudes occur near the plate boundaries: deep ocean trenches are associated with subduction zones and mountain ranges with collision belts. The landforms of the more stable areas of the plates date back to a more remote past and, where emerged, have a more subdued relief that is in the first place related to the resistance of the rocks to humid tropical weathering Rising mountain ranges and emerging island arcs are subjected to rapid humid-tropical river erosions and mass movements. The erosion products accumulate in adjacent sedimentary basins where their increasing weight causes subsidence by gravity and isostatic compensations. Living and raised coral reefs, volcanoes, and fault scarps are important geomorphic indicators of active plate tectonics. Compartmental faults may strongly affect island arcs stretching perpendicular to the plate movement. This is the case on Java. Transcurrent faults and related pull-apart basins are a leading factor where plates meet at an angle, such as on Sumatra. The most complicated situation exists near the triple-junction and in the Moluccas. Modern research methods, such as GPS measurements of plate movements and absolute dating of volcanic outbursts and raised coral reefs are important tools. The mega-landforms resulting

  10. Comparative Study on UNDEX Resistance of the Air-backed Stiffened Plate with Various Covering Layers%覆盖层加筋板结构水下抗爆性能对比试验研究

    Institute of Scientific and Technical Information of China (English)

    肖锋; 谌勇; 黄修长; 朱大巍; 华宏星

    2013-01-01

    为提高潜艇的隐身性能,潜艇壳体表面常敷设声学覆盖层结构。声学覆盖层常设有各类空腔等特殊结构形式,在受到水下爆炸冲击波时空腔产生变形并吸收能量,对潜艇的抗冲击性能产生影响。分别对不同覆盖层及无覆盖层的加筋平板试件开展水下抗爆炸性能对比性试验研究。通过试验获取各加筋平板试件典型部位的加速度、应变响应。比较不同覆盖层对加筋平板结构的实际抗冲效果,为今后声学覆盖层的抗冲设计和研究提供参考。%In order to improve stealthy capacity of a submarine, acoustic layers with special hollow structures are usually covered on hull surfaces of the submarine. The hollow structures can deform and absorb energy when they are subjected to underwater explosion (UNDEX), which can greatly raise the submarine’s anti-shock performance. In this paper, comparative study on UNDEX resistance of the air-backed stiffened plate with various covering layers was carried out. The acceleration and strain responses of the typical positions of the stiffened plate were obtained by the testing. And the anti-shock effects of the stiffened plate with various covering layers were compared. The results may provide a guideline for the design and study of the acoustic covering layers against UNDEX.

  11. Clad plates for construction of apparatus

    International Nuclear Information System (INIS)

    Importance of clad plates on the field of the construction of apparatus for the chemistry and petrol chemistry. Description of a cladding process to bond permanently and integrally ferritic steels and corrosion resistant and heat resistant materials by rolling. Information on available combinations of materials and gauge as well as on indispensable requirements to be met by the quality of the material. Results of tests carried out on the bond. Distribution of the elements between the clad and the base material. Bond properties, corrosion behaviour, toughness values and tensile properties of clad plates, heat treatment, cutting and welding of clad plates. Demonstration of applications. (orig.)

  12. Create Your Plate

    Medline Plus

    Full Text Available ... deaths a year than breast cancer and AIDS combined. Your gift today will help us get closer ... Plate! Click on the plate sections below to add your food choices. Reset Plate Share Create Your ...

  13. Create Your Plate

    Medline Plus

    Full Text Available ... plates! Snap a photo and share it to social media with #CreateYourPlate . See the full gallery of submitted plates! * ... Insurance For Parents & Kids Know Your Rights We Can ...

  14. Analysis on the Standard Formulation of Steel Plate Resisting Dew-point Corrosion of Sulphuric Acid%耐硫酸露点腐蚀钢板的标准制定分析

    Institute of Scientific and Technical Information of China (English)

    孙根领

    2013-01-01

      介绍了耐硫酸露点腐蚀钢板的研发应用现状及标准化需求,并对产品标准制定的原则、范围以及产品的化学成分、机械性能、耐硫酸露点腐蚀性能、表面质量、内部质量等主要交付技术条件的制订情况进行了探讨。目前耐硫酸露点腐蚀用钢板标准已经通过了国家标准管理委员会审批,将于2013年5月1日正式实施。%This article introduced the development, application and standardization requirement of steel plate resisting dew-point corrosion of sulphuric acid and discussed the principle of standard formulation, the scope of the specification and technical delivery conditions, such as chemical composition, mechanical properties, sulphuric acid dew point corrosion resistance property, surface quality and internal quality. At present, the Standard has passed the national standard management committee for approval and will carry out formally on May 1, 2013.

  15. Wear Resistance of TiN Coating Prepared by Multi-arc Ion Plating on Aluminum Alloy Surface%铝合金表面多弧离子镀TiN涂层的耐磨性能

    Institute of Scientific and Technical Information of China (English)

    谭银元; 潘应君

    2009-01-01

    Wear resistance of TiN coating prepared by multi-arc ion plating on ZL109 aluminum alloy surface has been examined. The results show that wear resist-ance of the ZL109 aluminum alloy with multi-arc ion plating TiN coating can be significantly improved. With applying 1N and wearing for 90min, the abrasive width of the samples without TiN coating makes ap-proximately 2 times of that with TiN coating, and av-erage frictional coefficient of the samples with TiN coating makes approximately 50% of that without coating. With applying 2N, the morphology and abra-sive width are varied as time increases. The wear mor-phology of the ZL109 alloy samples with TiN coating is characterized by adhesive abrasion in early stage and by abrasive abrasion in last stage.%采用多弧离子镀在ZL109铝合金表面进行了TiN涂层处理,并对涂层的载荷耐磨性进行了分析和讨论.结果表明,ZL109铝合金表面多弧离子镀TiN涂层后,其耐磨性得到明显提高.在1 N的载荷下,连续磨损90 min时,未镀膜试样的磨痕宽度几乎是TiN试样的2倍,镀有TiN膜试样的平均摩擦因数几乎是未镀样的50%.在2 N的载荷下,由磨痕的形貌和宽度随时间的变化可见,镀有TiN涂层的试样在磨损前期,主要以粘着磨损为主,在磨损后期以磨粒磨损为主.

  16. An understanding of HSLA-65 plate steels

    Science.gov (United States)

    Sampath, K.

    2006-02-01

    HSLA-65 plate steels can be produced using one of five plate manufacturing techniques: normalizing, controlled rolling (CR), controlled rolling followed by accelerated cooling (CR-AC), direct quenching and tempering (DQT), or conventional quenching and tempering (Q&T). The HSLA-65 steels are characterized by low carbon content and low alloy content, and they exhibit a low carbon equivalent that allows improved plate weldability. These characteristics in turn (a) provide the steel plate with a refined microstructure that ensures high strength and toughness; (b) eliminate or substantially reduce the need for preheating during welding; (c) resist susceptibility to hydrogen-assisted cracking (HAC) in the weld heat affected zone (HAZ) when fusion (arc) welded using low heat-input conditions; and (d) depending on section thickness, facilitate high heat-input welding (about 2 kJ/mm) without significant loss of strength or toughness in the HAZ. However, application of this plate manufacturing process and of these controls produces significant differences in the metallurgical structure and range of mechanical properties of the HSLA-65 plate steels both among themselves and versus conventional higher strength steel (HSS) plates. For example, among the HSLA-65 plate steels, those produced by Q&T exhibit minimal variability in mechanical properties, especially in thicker plates. Besides variability in mechanical properties depending on plate thickness, the CR and CR-AC plate steels exhibit a relatively higher yield strength to ultimate tensile strength (YS/UTS) ratio than do DQT and Q&T steels. Such differences in processing and properties of HSLA-65 plate steels could potentially affect the selection and control of various secondary fabrication practices, including arc welding. Consequently, fabricators must exercise extreme caution when transferring allowable limits of certified secondary fabrication practices from one type of HSLA-65 plate steel to another, even for the

  17. Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

    CERN Document Server

    SAE Aerospace Standards. London

    2012-01-01

    Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

  18. Voltage-current characteristics of a pin-plate system with different plate configurations

    International Nuclear Information System (INIS)

    In this paper, the voltage-current (V-I) characteristics of a pin-plate system with four types of collection plate configurations are studied experimentally. The collection plates consider a single metal plate, a metal plate with a fly ash cake layer, a metal plate with a clean filter media and a metal plate with a dirty filter media. The results show that the clean filter media has no obvious effect on the V-I characteristics. But the dirty filter media reduces the current density because of its high resistance. The thick fly ash cake layer increase current density because of the anti-corona effect but the increment is not very obvious.

  19. Modeling the hydrodynamics of phloem sieve plates

    Directory of Open Access Journals (Sweden)

    Kaare Hartvig Jensen

    2012-07-01

    Full Text Available Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play a crucial role in protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. The resistance to the flow of viscous sap in the phloem vascular system is strongly affected by the presence of the sieve plates, but the hydrodynamics of the flow through them remains poorly understood. We propose a theoretical model for quantifying the effect of sieve plates on the phloem in the plant, thus unifying and improving previous work in the field. Numerical simulations of the flow in real and idealized phloem channels verify our model, and anatomical data from 19 plant species are investigated. We find that the sieve plate resistance is correlated to the cell lumen resistance, and that the sieve plate and the lumen contribute almost equally to the total hydraulic resistance of the phloem translocation pathway.

  20. Effects of passive films on corrosion resistance of uncoated SS316L bipolar plates for proton exchange membrane fuel cell application

    Science.gov (United States)

    Yang, Ying; Ning, Xiaohui; Tang, Hongsheng; Guo, Liejin; Liu, Hongtan

    2014-11-01

    The effects of passive films on the corrosion behaviors of uncoated SS316L in anode and cathode environments of proton exchange membrane fuel cells (PEMFCs) are studied. Potentiodynamic and potentiostatic polarizations are employed to study the corrosion behavior; Mott-Schottky measurements are used to characterize the semiconductor properties of passive films; X-ray photoelectron spectroscopy (XPS) analyses are used to identify the compositions and the depth profiles of passive films. The passive films formed in the PEMFC anode and cathode environments under corresponding conditions both behave as n-type semiconductor. The passive film formed in the anode environment has a single-layer structure, Cr is the major element (Cr/Fe atomic ratio > 1), and the Cr/Fe atomic ratio decreases from the surface to the bulk; while the passive film formed in the PEMFC cathode environment has a bi-layer structure, Fe is the major element (Cr/Fe atomic ratio < 0.5), and in the external layer of the bi-layer structure Fe content increases rapidly and gradually in the internal layer. SS316L shows better corrosion resistance owing to both the high content of Cr oxide in the passive film and low band bending in normal PEMFC anode environments.

  1. Degradation of SS316L bipolar plates in simulated fuel cell environment: Corrosion rate, barrier film formation kinetics and contact resistance

    Science.gov (United States)

    Papadias, Dionissios D.; Ahluwalia, Rajesh K.; Thomson, Jeffery K.; Meyer, Harry M.; Brady, Michael P.; Wang, Heli; Turner, John A.; Mukundan, Rangachary; Borup, Rod

    2015-01-01

    A potentiostatic polarization method is used to evaluate the corrosion behavior of SS316L in simulated anode and cathode environments of polymer electrolyte fuel cells. A passive barrier oxide film is observed to form and reach steady state within ∼10 h of polarization, after which time the total ion release rates are low and nearly constant at ∼0.4 μg cm-2 h-1 for all potentials investigated. The equilibrium film thickness, however, is a function of the applied potential. The main ionic species dissolved in the liquid are predominately Fe followed by Ni, that account for >90% of the steady-state corrosion current. The dissolution rate of Cr is low but increases systematically at potentials higher than 0.8 V. The experimental ion release rates can be correlated with a point defect model using a single set of parameters over a broad range of potentials (0.2-1 V) on the cathode side. The interfacial contact resistance measured after 48 h of polarization is observed to increase with increase in applied potential and can be empirically correlated with applied load and oxide film thickness. The oxide film is substantially thicker at 1.5 V possibly because of alteration in film composition to Fe-rich as indicated by XPS data.

  2. Effects of passive films on corrosion resistance of uncoated SS316L bipolar plates for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Highlights: • The passive film formed at PEMFC anode side shows a single layer structure. • The passive film formed at PEMFC cathode side shows a bi-layer structure. • The Cr/Fe atomic ratios in passive films formed at different side are different. • The passive films behave as n-type semiconductor at both anode and cathode sides. • The anode/cathode potential is positive than the flatband potential of passive film. - Abstract: The effects of passive films on the corrosion behaviors of uncoated SS316L in anode and cathode environments of proton exchange membrane fuel cells (PEMFCs) are studied. Potentiodynamic and potentiostatic polarizations are employed to study the corrosion behavior; Mott-Schottky measurements are used to characterize the semiconductor properties of passive films; X-ray photoelectron spectroscopy (XPS) analyses are used to identify the compositions and the depth profiles of passive films. The passive films formed in the PEMFC anode and cathode environments under corresponding conditions both behave as n-type semiconductor. The passive film formed in the anode environment has a single-layer structure, Cr is the major element (Cr/Fe atomic ratio > 1), and the Cr/Fe atomic ratio decreases from the surface to the bulk; while the passive film formed in the PEMFC cathode environment has a bi-layer structure, Fe is the major element (Cr/Fe atomic ratio < 0.5), and in the external layer of the bi-layer structure Fe content increases rapidly and gradually in the internal layer. SS316L shows better corrosion resistance owing to both the high content of Cr oxide in the passive film and low band bending in normal PEMFC anode environments

  3. 混凝土输送泵眼睛板耐磨堆焊焊条的研究%Research on Wear Resistant Surfacing Welding Electrode for Concrete Pump Eye Plate

    Institute of Scientific and Technical Information of China (English)

    刘宇雷; 闵庆凯

    2013-01-01

    A wear resistant surfacing welding electrode for concrete pump eye plate and the processing property were studied. The results show that the wear resistant and hardness can greatly improve after adding a certain percentage of graphite into the electrode coating. The detachability of the slag on the electrode is easy and the slag inclusion is less, the welding seam has only less tiny slag. So the multi-weld layer and multi-weld seam does not need to remove the slag. Such not only ensure the efficiency of the parts, but also extend its useful life. The excellent economic benefits were obtained ,which can realize the expected effect.%主要阐述了应用于混凝土输送泵眼睛板耐磨堆焊焊条的研究.实验中通过对其堆焊焊条工艺性能的研究,得出了在堆焊焊条的药皮中,添加一定量的石墨元素后,堆焊金属的焊缝处所具有的耐磨性和硬度都能够大幅显著提升,夹渣少易脱渣,同时焊道处仅有少量微渣存在,多道多层堆焊时就不必清渣,这样既能保证零件的工作效率,又能延长其使用寿命,还能取得较好的经济效益,达到了预期效果.

  4. 燃料电池用钛双极板表面Cr/TiN/Ti复合涂层的导电性及耐蚀性能%Electrical Conductivity and Corrosion Resistance of Cr/TiN/Ti Composite Films Coated on Titanium Bipolar Plate for Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    付广艳; 戴世鑫; 牛云松; 于志明

    2011-01-01

    应用空心阴极离子镀工艺在质子交换膜燃料电池用钛双极板试样表面上沉积了总厚度约3pm的Cr/TiN/Ti纳米晶复合镀膜.测定了纳米晶复合镀膜钛板和裸钛板的接触电阻,采用极化曲线评价其在分别通入O2和H2的60℃,0.05mol/LH2SO4+2mg/LNaF溶液中的耐蚀性能.结果表明,镀膜钛板的接触电阻明显低于裸钛板,在1000N/cm^2的压力下镀膜试样的接触电阻值约为12mΩ·cm^2;在通入H2的情况下,Cr/TiN/Ti纳米晶复合镀膜钛板的维钝电流密度与裸钛板相比降低了一个数量级,耐腐蚀性能得到明显%Cr/TiN/Ti nanocrystalline composite fihns of about 3 μm were deposited on titanium bipolar plates for proton exchange membrane fuel cell (PEMFC) by hollow cathode deposition (HCD) ion plating. The electrical contact resistance of Ti plate with and without the nanocrystalline films was tested respectively, and their electrochemical corrosion performance was evaluated in 0.05 mol/L H2SO4+2 mg/L NaF solutions bubbled with H2 or O2 at 60℃ by means of po larization measurements. The results show that the contact resistance of the coated Ti plate was obviously lower than that of bare Ti plate, with about 12 mQ.cm2 under a compressive presure 1000 N/cm2. The passivation current density of the coated Ti plate was one order of magnitude smaller than that of the bare Ti plate under the condition of charging hydrogen, suggesting that the corrosion resistance of titanium bipolar plate is greatly improved by the deposition of Cr/TiN/Ti nanocrystalline composite films.

  5. Limb lengthening over plate

    Directory of Open Access Journals (Sweden)

    Ruta Kulkarni

    2012-01-01

    Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis.

  6. Create Your Plate

    Science.gov (United States)

    ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  7. Create Your Plate

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    Full Text Available ... plates! Snap a photo and share it to social media with #CreateYourPlate . See the full gallery of ... Congress Research & Practice We Are Research Leaders We Support Your Doctor Student Resources Patient Access to Research ...

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    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

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    Full Text Available ... plates! Snap a photo and share it to social media with #CreateYourPlate . See the full gallery of ... you have an easy portion control solution that works. Last Reviewed: October 8, 2015 Last Edited: October ...

  12. Create Your Plate

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    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

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    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... Blog Online Community Site Menu Are You at Risk? Diagnosis Lower Your Risk Risk Test Alert Day ...

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    Full Text Available ... seven simple steps . We want to see your real-life healthy plates! Snap a photo and share ... filled with non-starchy vegetables and that your options are endless. Create Your Plate! Click on the ...

  15. Inevitability of Plate Tectonics on Super-Earths

    CERN Document Server

    Valencia, Diana; Sasselov, Dimitar D

    2007-01-01

    The recent discovery of super-Earths (masses less or equal to 10 earth-masses) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which influences a planet's thermal evolution and surface conditions. On Earth, plate tectonics has been proposed as a necessary condition for life. Here we show, that super-Earths will also have plate tectonics. We demonstrate that as planetary mass increases, the shear stress available to overcome resistance to plate motion increases while the plate thickness decreases, thereby enhancing plate weakness. These effects contribute favorably to the subduction of the lithosphere, an essential component of plate tectonics. Moreover, uncertainties in achieving plate tectonics in the one earth-mass regime disappear as mass increases: super-Earths, even if dry, will exhibit plate tectonic behaviour.

  16. Vibration of plates

    CERN Document Server

    Chakraverty, Snehashish

    2008-01-01

    Plates are integral parts of most engineering structures and their vibration analysis is required for safe design. This work provides a comprehensive introduction to vibration theory and analysis of two-dimensional plates. It offers information on vibration problems along with a discussion of various plate geometries and boundary conditions.

  17. MyPlate

    Science.gov (United States)

    ... MyPlate What Is MyPlate? Fruits All About the Fruit Group Nutrients and Health Benefits Tips to Help You Eat Fruits Food ... lives. What Is MyPlate? Fruits All About the Fruit Group Nutrients and Health Benefits Tips to Help You Eat Fruits Food ...

  18. Silicon-micromachined microchannel plates

    CERN Document Server

    Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

    2000-01-01

    Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

  19. Ion beams replace chrome plating

    International Nuclear Information System (INIS)

    Metal ion implantation is the process of altering surface properties by bombarding with high-energy metal ions. Because the process does not produce a coating, dimensions and bulk properties of the part remain unchanged, and implanted surfaces have no problems with adhesion, residual stress, or poor microstructure. Implanted surfaces can provide wear and/or corrosion resistance comparable with, or superior to, chrome plating. Furthermore, it is a relatively low-temperature process, which enables treatment of materials such as plastics, aluminum, and low-alloy steel. Furthermore, the performance of coatings can be improved by bombarding with ions during or after the coating process. Specifically, high-energy ions applied during deposition have been shown to reduce the required temperature for physical vapor deposition (PVD) systems, overcoming one of the major obstacles to replacing chromium plating with PVD coatings. This article will review the latest advances in metal-ion implantation equipment, with particular reference to economics and applications

  20. Performance of the ATLAS Resistive Plate Chambers

    CERN Document Server

    Cattani, G; The ATLAS collaboration

    2010-01-01

    The ATLAS detector is now installed at CERN's LHC and fully operational. RPCs provide the first-level muon trigger and the measurement of the non bending coordinate in the barrel region. To achieve these goals, a system of about 4000 gas gaps operating in avalanche mode was built (resulting in a total of $sim$ 350000 readout strips). Such a large-scale system allows the study of the performance of RPCs with unprecedented sensitivity to rare effects. On the other hand, a prerequisite for this kind of studies is the exact knowledge of the working point of the detector, and its uniformity along the whole muon spectrometer. This means fine-tuning thousands of parameters (involving both front end electronics and gap voltages), as well as constantly monitoring performance and environmental quantities such as gap/panel efficiencies, average cluster size, temperature, gas flow, gap currents, counting rates. We will present here an overview of this effort and some example results, addressing in particular three aspect...

  1. Modeling the hydrodynamics of Phloem sieve plates

    DEFF Research Database (Denmark)

    Jensen, Kaare Hartvig; Mullendore, Daniel Leroy; Holbrook, Noel Michele;

    2012-01-01

    Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play a...... crucial role in protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. The resistance to the flow of viscous sap in the phloem vascular system is strongly affected by the presence of the sieve plates, but the hydrodynamics of the flow through them remains poorly...... understood. We propose a theoretical model for quantifying the effect of sieve plates on the phloem in the plant, thus unifying and improving previous work in the field. Numerical simulations of the flow in real and idealized phloem channels verify our model, and anatomical data from 19 plant species are...

  2. Optimisation and Characterisation of Glass RPC for India-based Neutrino Observatory Detectors

    OpenAIRE

    Kanishka, R.; Bhatnagar, Vipin; Indumathi, D.

    2016-01-01

    The proposed magnetised Iron CALorimeter detector (ICAL) to be built in the India-based Neutrino Observatory (INO) laboratory aims to detect atmospheric muon neutrinos. In order to achieve improved physics results, the constituent components of the detector must be fully understood by proper characterisation and optimisation of various parameters. Resistive Plate Chambers (RPCs) are the active detector elements in the ICAL detector and can be made of glass or bakelite. The number of RPCs requ...

  3. Performances of RPC detectors with tracking and timing electronics

    International Nuclear Information System (INIS)

    The bakelite Resistive Plate Counters (RPC) for the COVER-PLASTEX experiment have been tested with special tracking and timing electronics developed by the T and T collaboration for use as a front-end electronics able to give position and arrival time for each particle in the EAS front crossing the detector. Results on single counting rate, efficiency, time resolution, signal shape and after pulse presence are given as a function of the high voltage and input signal threshold. (orig.)

  4. 电镀Zn-Ni合金镀层结构及耐蚀性能研究%Study on Microstructure and Corrosion Resistance of Alkaline Zn-Ni Alloy Plating

    Institute of Scientific and Technical Information of China (English)

    刘晓东; 聂朝胤; 赵洋; 聂燕中

    2015-01-01

    在一种Zn‐Ni合金碱性电镀体系中,应用电化学沉积法在304不锈钢表面快速制备了Zn‐Ni合金镀层,采用扫描电子显微镜、X射线衍射仪和电化学工作站,对Zn‐Ni合金镀层及Zn镀层的微观结构及耐蚀性能进行了对比研究.结果表明:所获得的Zn‐Ni合金镀层晶型为γ晶型,镍和锌的质量分数分别为14.37%和85.63%;通过不同电介质溶液模拟不同环境考察Zn‐Ni合金镀层的耐蚀性,在质量分数为5%的NaCl溶液中Zn‐Ni合金镀层的自腐蚀电位相对于Zn镀层正移了245mV,腐蚀推动力比Zn镀层小,其腐蚀电流密度是Zn镀层的0.15倍;在1mol/L的NaOH溶液中,Zn‐Ni合金镀层的自腐蚀电位相对于Zn镀层正移了59mV,其腐蚀电流密度是Zn镀层的0.86倍,所获得的Zn‐Ni合金镀层在中性溶液和碱性溶液中都具有很强的耐蚀性.%A Zn‐Ni alloy coating was quickly prepared on 304 stainless steel surface in an alkaline Zn‐Ni al‐loy plating solution with the electrochemical deposition method .Its microstructure was testified with scan‐ning electron microscopy and X‐ray diffraction graph ,and the corrosion resistance of the Zn‐Ni alloy coat‐ing and the Zn coating was studied and compared with electrochemical workstation .The results showed that the crystal shape of the Zn‐Ni alloy coating obtained in this study was of the γ‐shape and that the con‐tent of nickel and zinc was 14.37% and 85.63% ,respectively .The corrosion resistance of the Zn‐Ni alloy coating was testified in environments with different dielectric solutions .The potential of the Zn‐Ni alloy coating was 245 mV higher than that of the Zn coating in a 5% NaCl solution ,which indicated the driving force on corrosion on the surface of the Zn‐Ni alloy was much less than that of Zn ,and the corrosion cur‐rent density was 0.15 times as much as that of Zn .The potential of the Zn‐Ni alloy coating was 59 m

  5. Automatic Licenses Plate Recognition

    OpenAIRE

    Ronak P Patel; Narendra M Patel; Keyur Brahmbhatt

    2013-01-01

    This paper describes the Smart Vehicle Screening System, which can be installed into a tollboothfor automated recognition of vehicle license plate information using a photograph of a vehicle. An automatedsystem could then be implemented to control the payment of fees, parking areas, highways, bridges ortunnels, etc. This paper contains new algorithm for recognition number plate using Morphological operation,Thresholding operation, Edge detection, Bounding box analysis for number plate extract...

  6. Fractal Plate Tectonics

    OpenAIRE

    Sornette, D.; V. F. Pisarenko

    2002-01-01

    We analyze in details the statistical significance of the claim by Bird [2002] of a power law distribution of plate areas covering the Earth and confirm that the power law with exponent 0.25 +- 0.05 is the most robust and parsimonious model for all plates, including the very largest plates, when taking into account the constraint that the plates areas must sum up to 4 pi steradians. We propose a general class of fragmentation models that rationalize this observation and discuss the implicatio...

  7. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  8. Chrome-plating of titanium alloys and their performance

    International Nuclear Information System (INIS)

    The impact of technological parameters by electrochemical chrome-plating of titanium alloys on their mechanical properties, wear resistance, fatigue resistance, antifriction characteristics, hydridation and hydrogen distribution in the base and coating is studied. The evaluation of the alloys and coatings overgrowing with microorganisms is given. The rational compositions of solutions and regimes of titanium alloys treatment by their multiple (up to 6 times) chrome-plating are determined

  9. Create Your Plate

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  10. Create Your Plate

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  11. Create Your Plate

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    Full Text Available ... Islanders American Indian/Alaska Native Programs Older Adults Family Link Diabetes EXPO Upcoming Diabetes EXPOs EXPO Volunteer ... plates! Snap a photo and share it to social media with #CreateYourPlate . See the full gallery of ...

  12. Create Your Plate

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    Full Text Available ... and Type 2 Diabetes Know Your Rights Employment Discrimination Health Care Professionals Law Enforcement Driver's License For ... critical diabetes research and support vital diabetes education services that improve the lives of those with ... plates! Snap a photo and share it to social media with #CreateYourPlate . See the full gallery of ...

  13. Rapid Prototyping Bipolar Plate of PEMFC by Gelcasting

    Institute of Scientific and Technical Information of China (English)

    LUO Bing; CHEN Shang-wei; HUANG Ming-yu; WANG Lian-jun

    2006-01-01

    Bipolar plate is one key component of proton exchange membrane fuel cell (PEMFC). According to this paper, mesocarbon microbeads were used as raw materials for forming the green bodies of bipolar plates with complex flow channels by gelcasting technique. Then, the final bipolar plates would be gained after the green parts were died, burned out and sintered. Meanwhile, its properties are researched and evaluated by the test of flexible strength and electric resistivity. The resultant flexural strength of sintered sample is 67 Mpa and the electric resistivity is 52 μΩ·m.

  14. PEM fuel cell bipolar plate material requirements for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E. [Los Alamos National Lab., NM (United States)] [and others

    1996-04-01

    Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

  15. Plate heat exchanger

    International Nuclear Information System (INIS)

    In a plate heat exchanger required to handle corrosive, toxic or radioactive fluids, wherein each plate has a peripheral recess or like formation adapted for receiving an elastomeric gasket, the plates are welded together in pairs by the method comprising the steps of inserting into the gasket recess of a first plate of said pair a metal packing piece and welding the second place (e.g. by a laser or electron beam weld running along the base of the recess) superimposing a second plate on to the first in contact with the packing piece and welding the second plate to the packing piece (e.g. by a laser or electron beam weld). The packing piece may be of hollow or solid cross section and is preferably of the same material (e.g. titanium or stainless steel) as the plates. In use a service fluid in heat exchange with the said corrosive etc. fluid is confined by peripheral and normally elastomeric gaskets. (author)

  16. Anisotropic elastic plates

    CERN Document Server

    Hwu, Chyanbin

    2010-01-01

    As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a

  17. Inversion for the driving forces of plate tectonics

    Science.gov (United States)

    Richardson, R. M.

    1983-01-01

    Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

  18. Effect of plate roughness on the field near RPC plates

    Science.gov (United States)

    Jash, A.; Majumdar, N.; Mukhopadhyay, S.; Chattopadhyay, S.

    2016-06-01

    The inner surfaces of the electrodes encompassing the gas volume of a Resistive Plate Chamber (RPC) have been found to exhibit asperities with, grossly, three kind of features. The desired uniform electric field within the gas volume of RPC is expected to be affected due to the presence of these asperities, which will eventually affect the final response from the detector. In this work, an attempt has been made to model the highly complex roughness of the electrode surfaces and compute its effect on the electrostatic field within RPC gas chamber. The calculations have been performed numerically using Finite Element Method (FEM) and Boundary Element Method (BEM) and the two methods have been compared in this context.

  19. Effect of plate roughness on the field near RPC plates

    CERN Document Server

    Jash, Abhik; Mukhopadhyay, Supratik; Chattopadhyay, Subhasis

    2016-01-01

    The inner surfaces of the electrodes encompassing the gas volume of a Resistive Plate Chamber (RPC) have been found to exhibit asperities with three kind of features grossly. The desired uniform electric field within the gas volume of RPC is expected to be affected due to the presence of these asperities, which will eventually affect the final response from the detector. In this work, an attempt has been made to model the highly complex roughness of the electrode surfaces and compute its effect on the electrostatic field within RPC gas chamber. The calculations have been performed numerically using Finite Element Method (FEM) and Boundary Element Method (BEM) and the two methods have been compared in this context.

  20. Correlation between Wear Resistance and Lifetime of Electrical Contacts

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-01-01

    Full Text Available Electrical contacts are usually plated in order to prevent corrosion. Platings of detachable electrical contacts experience wear because of the motion between contacts. Once the protecting platings have been worn out, electrical contacts will fail rapidly due to corrosion or fretting corrosion. Therefore the wear resistance of the platings is a very important parameter for the long lifetime of electrical contacts. Many measures which improve the wear resistance can diminish the conductivity of the platings. Due to the fact that platings of electrical contacts must have both a high wear resistance and a high electrical conductivity, the manufacturing of high performance platings of electrical contacts poses a great challenge. Our study shows firstly the correlation between the wear resistance of platings and lifetime of electrical contacts and then the measures, which improve the wear resistance without impairing the electrical performance of the contacts.

  1. Create Your Plate

    Medline Plus

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  3. Tectonic Plate Movement.

    Science.gov (United States)

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  4. Create Your Plate

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  7. Plate tectonics: Metamorphic myth

    Science.gov (United States)

    Korenaga, Jun

    2016-01-01

    Clear evidence for subduction-induced metamorphism, and thus the operation of plate tectonics on the ancient Earth has been lacking. Theoretical calculations indicate that we may have been looking for something that cannot exist.

  8. Create Your Plate

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    Full Text Available ... Student Resources History of Diabetes Resources for School Projects How to Reference Our Site Diabetes Basics Myths ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  16. An investigation of coated aluminium bipolar plates for PEMFC

    International Nuclear Information System (INIS)

    Highlights: ► Coated aluminium bipolar plates demonstrate the hydrophobic property than the raw material. ► The corrosion behaviour of bipolar plate decreases the PEMFC performance severely. ► These PEMFCs are measured by current–voltage (I–V) curve test. ► The oxide film increases the interfacial contact resistance. -- Abstract: The performance of Al-alloy bipolar plates for the PEMFC (proton exchange membrane fuel cell) system is investigated in this paper. The metallic bipolar plates are modified with a Ni–P coating. The performance of the Al-alloy bipolar plates is evaluated by the coating structure, corrosion resistance, contact angle and single cell performance. The results indicate that the coated aluminium bipolar plates demonstrate hydrophobic and anti-corrosive properties. The hydrophobic property increases the contact angle on the surface from 46.08° to 80.51°. Meanwhile, the corrosion rate of the Ni–P coating can be over 1 order of magnitude lower than that of the substrate. Hence, the substrate with the coating maintains superior performance under the long term test. The present study proves that both the hydrophobicity and corrosion resistance significantly affect the metallic bipolar plate.

  17. The Dynamics of Plate Tectonics and Mantle Flow: From Local to Global Scales

    OpenAIRE

    Stadler, Georg; Gurnis, Michael; Burstedde, Carsten; Wilcox, Lucas C.; Alisic, Laura; Ghattas, Omar

    2010-01-01

    Plate tectonics is regulated by driving and resisting forces concentrated at plate boundaries, but observationally constrained high-resolution models of global mantle flow remain a computational challenge. We capitalized on advances in adaptive mesh refinement algorithms on parallel computers to simulate global mantle flow by incorporating plate motions, with individual plate margins resolved down to a scale of 1 kilometer. Back-arc extension and slab rollback are emergent consequences of sla...

  18. Brazing with plated alloys

    International Nuclear Information System (INIS)

    The use of braze alloy preforms on complex geometry components is at times a very difficult task requiring extensive handling of the parts or even tack welding of the preform to ensure that it is held in place. One method of overcoming these difficulties is the use of plated braze alloys (i.e., filler metals) applied directly to the braze region. Plating helps to avoid the potential for contamination resulting from handling and also ensures that the braze alloy is located properly. Examples are discussed in which an electroplated silver-copper alloy is used as an alternative to the BAg8 preforms and electroless nickel is used as a replacement for an amorphous Ni-P braze alloy foil. A toroidal cooling plate with helical flow channels was fabricated from oxygen-free high conductivity (OFHC) and brazed using the electroplated silver-copper alloy. The silver-copper braze alloy was applied to the copper substrate in a laminated fashion of alternating layers of silver and copper, which in combination approximated the eutectic composition (72% Ag-28% Cu by weight). Examination of the brazed assemblies indicated that in both cases the advantages of using plated braze alloys are numerous. These advantages include decreased labor, improved cleanliness and exactness of braze alloy placement. The primary disadvantage was an increased tendency for solidification defects presumably resulting from contaminants in the plating baths. This last observation is presently being examined in greater detail. The end results is that the assemblies brazed with the plated alloys were acceptable for the intended application and that the use of plating facilitated the successful assembly of these components

  19. Temperature field of steel plate cooling process after plate rolling

    OpenAIRE

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time,...

  20. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    2014-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  1. Automatic Number Plate Recognition System

    OpenAIRE

    Rajshree Dhruw; Dharmendra Roy

    2014-01-01

    Automatic Number Plate Recognition (ANPR) is a mass surveillance system that captures the image of vehicles and recognizes their license number. The objective is to design an efficient automatic authorized vehicle identification system by using the Indian vehicle number plate. In this paper we discus different methodology for number plate localization, character segmentation & recognition of the number plate. The system is mainly applicable for non standard Indian number plates by recognizing...

  2. Anterior cervical plating

    Directory of Open Access Journals (Sweden)

    Gonugunta V

    2005-01-01

    Full Text Available Although anterior cervical instrumentation was initially used in cervical trauma, because of obvious benefits, indications for its use have been expanded over time to degenerative cases as well as tumor and infection of the cervical spine. Along with a threefold increase in incidence of cervical fusion surgery, implant designs have evolved over the last three decades. Observation of graft subsidence and phenomenon of stress shielding led to the development of the new generation dynamic anterior cervical plating systems. Anterior cervical plating does not conclusively improve clinical outcome of the patients, but certainly enhances the efficacy of autograft and allograft fusion and lessens the rate of pseudoarthrosis and kyphosis after multilevel discectomy and fusions. A review of biomechanics, surgical technique, indications, complications and results of various anterior cervical plating systems is presented here to enable clinicians to select the appropriate construct design.

  3. Plates with Incompatible Prestrain

    OpenAIRE

    Bhattacharya, Kaushik; Lewicka, Marta; Schäffner, Mathias

    2016-01-01

    We study effective elastic behavior of the incompatibly prestrained thin plates, where the prestrain is independent of thickness and uniform through the plate’s thickness h. We model such plates as three-dimensional elastic bodies with a prescribed pointwise stress-free state characterized by a Riemannian metric G, and seek the limiting behavior as h→0. We first establish that when the energy per volume scales as the second power of h, the resulting Γ-limit is a Kirchhoff-type bending theory....

  4. Plating on Zircaloy-2

    International Nuclear Information System (INIS)

    Zircaloy-2 is a difficult alloy to coat with an adherent electroplate because it easily forms a tenacious oxide film in air and aqueous solutions. Procedures reported in the literature and those developed at SLL for surmounting this problem were investigated. The best results were obtained when specimens were first etched in either an ammonium bifluoride/sulfuric acid or an ammonium bifluoride solution, plated, and then heated at 7000C for 1 hour in a constrained condition. Machining threads in the Zircaloy-2 for the purpose of providing sites for mechanical interlocking of the plating also proved satisfactory

  5. Highly adhesive metal plating on Zylon fiber via iodine pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Fatema, Ummul Khair [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567 (Japan); Gotoh, Yasuo, E-mail: ygotohy@shinshu-u.ac.jp [Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567 (Japan)

    2011-11-01

    Highly adhesive metal plating was performed on poly(p-phenylene-2,6-benzobisoxazole) fiber named Zylon via iodine pretreatment followed by electroless plating. First, iodine components were selectively doped into the inner part of the fiber near the surface through iodine vapor exposure. The doped iodine was converted to palladium iodide particles by treating with palladium chloride solution. After the reduction of the iodide to metal palladium particles, electroless copper plating was conducted on the fiber. A uniform copper layer was deposited on the fiber surface and exhibited high durability in durability tests such as ultrasonic exposure, tape peeling-off, and corrosion in NaCl solution. This durability was attributed to the palladium particles formed at the fiber surface that served as an anchor for the plated layer as well as an electroless plating catalyst. The plated fibers also possessed electrical conductivity. Although the tensile strength of the Zylon fiber decreased from 5.8 to 4.9 GPa after undergoing the pretreatment and plating processes, the light shielding effect improved the light resistance of the plated fibers in terms of tensile properties. After 18 days of xenon lamp exposure, the plated fibers retained 74% of its initial strength, whereas that of untreated fibers decreased to 43%.

  6. Highly adhesive metal plating on Zylon fiber via iodine pretreatment

    International Nuclear Information System (INIS)

    Highly adhesive metal plating was performed on poly(p-phenylene-2,6-benzobisoxazole) fiber named Zylon via iodine pretreatment followed by electroless plating. First, iodine components were selectively doped into the inner part of the fiber near the surface through iodine vapor exposure. The doped iodine was converted to palladium iodide particles by treating with palladium chloride solution. After the reduction of the iodide to metal palladium particles, electroless copper plating was conducted on the fiber. A uniform copper layer was deposited on the fiber surface and exhibited high durability in durability tests such as ultrasonic exposure, tape peeling-off, and corrosion in NaCl solution. This durability was attributed to the palladium particles formed at the fiber surface that served as an anchor for the plated layer as well as an electroless plating catalyst. The plated fibers also possessed electrical conductivity. Although the tensile strength of the Zylon fiber decreased from 5.8 to 4.9 GPa after undergoing the pretreatment and plating processes, the light shielding effect improved the light resistance of the plated fibers in terms of tensile properties. After 18 days of xenon lamp exposure, the plated fibers retained 74% of its initial strength, whereas that of untreated fibers decreased to 43%.

  7. Inevitability of Plate Tectonics on Super-Earths

    OpenAIRE

    Valencia, Diana; O'Connell, Richard J.; Sasselov, Dimitar D.

    2007-01-01

    The recent discovery of super-Earths (masses less or equal to 10 earth-masses) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which influences a planet's thermal evolution and surface conditions. On Earth, plate tectonics has been proposed as a necessary condition for life. Here we show, that super-Earths will also have plate tectonics. We demonstrate that as planetary mass increases, the shear stress available to overcome resistance t...

  8. ELECTROLESS NICKEL PLATING ON CHITOSAN-MODIFIED WOOD VENEER

    OpenAIRE

    Lijuan Wang; Haibing Liu

    2011-01-01

    An activation process involving chitosan was conducted to prepare electroless nickel plated wood veneers for electromagnetic interference (EMI) shielding. In this process Pd(Ⅱ) ions were chemically adsorbed on wood surface modified with chitosan. Then they were reduced and dipped into a plating bath in which Ni-P co-deposition was successfully initiated. The coatings were characterized by SEM-EDS and XRD. The metal deposition, surface resistivity, and electromagnetic shielding effectiveness w...

  9. Review on Electroless Plating Ni-P Coatings for Improving Surface Performance of Steel

    Science.gov (United States)

    Zhang, Hongyan; Zou, Jiaojuan; Lin, Naiming; Tang, Bin

    2014-04-01

    Electroless plating has been considered as an effective approach to provide protection and enhancement for metallic materials with many excellent properties in engineering field. This paper begins with a brief introduction of the fundamental aspects underlying the technological principles and conventional process of electroless nickel-phosphorus (Ni-P) coatings. Then this paper discusses different electroless nickel plating, including binary plating, ternary composite plating and nickel plating with nanoparticles and rare earth, with the intention of improving the surface performance on steel substrate in recent years in detail. Based on different coating process, the varied features depending on the processing parameters are highlighted. Separately, diverse preparation techniques aiming at improvement of plating efficiency are summarized. Moreover, in view of the outstanding performance, such as corrosion resistance, abrasive resistance and fatigue resistance, this paper critically reviews the behaviors and features of various electroless coatings under different conditions.

  10. Nuclear reactor alignment plate configuration

    Science.gov (United States)

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  11. The Plate Tectonics Project

    Science.gov (United States)

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  12. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  13. Parallel plate detectors

    International Nuclear Information System (INIS)

    A 5x3cm2 (timing only) and a 15x5cm2 (timing and position) parallel plate avalanche counters (PPAC) are considered. The theory of operation and timing resolution is given. The measurement set-up and the curves of experimental results illustrate the possibilities of the two counters

  14. Create Your Plate

    Medline Plus

    Full Text Available ... October 8, 2015 Last Edited: October 19, 2015 Articles from Diabetes Forecast® magazine: wcie-meal-planning, In this section Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian ...

  15. Create Your Plate

    Medline Plus

    Full Text Available ... Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning What Can I Eat? Making Healthy Food Choices Diabetes Superfoods Non-starchy Vegetables Grains and Starchy Vegetables Fats Alcohol What Can I Drink? Fruit Dairy Food Tips ...

  16. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate interactive tool to help Latinos/Hispanics balance the meals they love to better manage their ... your meal, add a low-calorie drink like water, unsweetened tea or coffee. Featured Product Precise Portions® ...

  17. Growth Plate Injuries

    Science.gov (United States)

    ... or muscular imbalance are prone to growth plate fractures, especially at the ankle and knee. Children who are born with insensitivity to pain ... arm bone) near the elbow. Type V: Compression Fracture Through Growth ... to occur at the knee or ankle. Prognosis is poor, since premature stunting ...

  18. Create Your Plate

    Medline Plus

    Full Text Available ... unsweetened tea or coffee. Featured Product Precise Portions® Go Healthy Travel Pack (4/Box) Taking the guesswork ... you are. Now, our best-selling, sectioned to-go plate with easy-sealing lid is offered in ...

  19. Create Your Plate

    Medline Plus

    Full Text Available ... meal-planning, In this section Food Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart-Healthy Foods donate ... Donate Today Diabetes touches everyone, and finding a cure is personal ...

  20. Shear design recommendations for stainless steel plate girders

    OpenAIRE

    Saliba, Najib; Real, E.; Gardner, Leroy

    2014-01-01

    The behaviour and design of stainless steel plate girders loaded in shear is investigated in this paper. A review of existing methods for the design of stainless steel plate girders, including codified provisions, is first presented. A database of thirty-four experiments carried out on austenitic, duplex and lean duplex stainless steel plate girders is then reported, and used to assess the current shear resistance design equations from Eurocode 3: Part 1.4 and Eurocode 3: Part 1.5 and the rec...

  1. Characterization of the commercially-available fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a marker for chloroquine resistance and uptake in a 96-well plate assay.

    Directory of Open Access Journals (Sweden)

    Cheryl C Y Loh

    Full Text Available Chloroquine was a cheap, extremely effective drug against Plasmodium falciparum until resistance arose. One approach to reversing resistance is the inhibition of chloroquine efflux from its site of action, the parasite digestive vacuole. Chloroquine accumulation studies have traditionally relied on radiolabelled chloroquine, which poses several challenges. There is a need for development of a safe and biologically relevant substitute. We report here a commercially-available green fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a proxy for chloroquine accumulation. This compound localized to the digestive vacuole of the parasite as observed under confocal microscopy, and inhibited growth of chloroquine-sensitive strain 3D7 more extensively than in the resistant strains 7G8 and K1. Microplate reader measurements indicated suppression of LynxTag-CQGREEN efflux after pretreatment of parasites with known reversal agents. Microsomes carrying either sensitive- or resistant-type PfCRT were assayed for uptake; resistant-type PfCRT exhibited increased accumulation of LynxTag-CQGREEN, which was suppressed by pretreatment with known chemosensitizers. Eight laboratory strains and twelve clinical isolates were sequenced for PfCRT and Pgh1 haplotypes previously reported to contribute to drug resistance, and pfmdr1 copy number and chloroquine IC50s were determined. These data were compared with LynxTag-CQGREEN uptake/fluorescence by multiple linear regression to identify genetic correlates of uptake. Uptake of the compound correlated with the logIC50 of chloroquine and, more weakly, a mutation in Pgh1, F1226Y.

  2. Industrialization of the ion plating process

    Science.gov (United States)

    Spalvins, T.

    1976-01-01

    A new process referred to as ion plating by induction heating (IPIH) is described, which combines the advantages of both ion plating and induction heating. The IPIH apparatus consists of the specimen (cathode) to be coated and the evaporation heating source, which is a ceramic crucible containing the metal to be heated. The specimen is an internal part of the high-voltage ceramic-metal vacuum feedthrough and is connected to the negative terminal of the high-voltage power supply, the positive terminal of the power supply being grounded. The plating conditions are the same as those most commonly used in industrial ion plating. A number of metals - such as nickel, iron, platinum - which were practically impossible to deposit by resistance heating evaporation can now be effectively evaporated and deposited to any desired thickness. Excellent adherence is observed for many metals deposited on various metal surfaces in thicknesses from 0.15 to 50 microns, regardless of the materials selected for coating and substrate.

  3. LOW VELOCITY RESPONSE CHARACTERISTICS OF COMPOSITE PLATE WITH EMBEDDED SHAPE MEMORY ALLOY

    Institute of Scientific and Technical Information of China (English)

    WuYongdong; ZhongWeifang; LiangYide

    2004-01-01

    This paper analyzes the characteristics of utilizing shape memory effect (SME) of shape memory alloy (SMA) in improving the low velocity impact resistance performance of composite plate by using finite element method. The constitutive relation for SMA hybrid composite plates is presented. The analytic model of finite element for SMA composite plate subjected to low velocity impact is established. The modified Hertz's contact law is used to determine the impact contact force. The computing procedures for solving the finite element equation using Newmark direct integration method are given. The numerical modelling results show that the SMA can effectively improve the low velocity impact resistance performance of composite plate.

  4. In vitro comparison of bioresorbable and titanium anterior cervical plates in the immediate postoperative condition.

    Science.gov (United States)

    Freeman, Andrew L; Derincek, Alihan; Beaubien, Brian P; Buttermann, Glenn R; Lew, William D; Wood, Kirkham B

    2006-12-01

    Bioresorbable plates have recently been used with anterior cervical discectomy and fusion (ACDF). Compared with metallic plates, bioresorbable plates provide segmental stabilization with minimal imaging artifact, eventual resorption, and increased load sharing. The objectives of the present study were to determine whether a bioresorbable plate can withstand simulated physiologic static and cyclic loading, to compare the reduction in flexibility provided by bioresorbable and titanium plates, and to quantify load sharing between the plate and spine with graft. Sixteen human cervical motion segments were tested to +/-2.5 Nm in flexion-extension, lateral bending, and axial rotation. Range of motion (ROM) was measured (1) in the intact state, (2) with ACDF without plating, (3) after addition of either a bioresorbable or titanium plate, and (4) after 500 cycles of combined flexion-extension and axial torsion. Load sharing was evaluated by applying the same fixed rotation both without and with the plate, and was calculated as the moment resisted by the uninstrumented ACDF expressed as a percentage of the plated ACDF state. No plate failures or graft migration occurred during testing. Compared with the uninstrumented ACDF, bioresorbable plates reduced mean ROM by 49% in flexion-extension and 25% in lateral bending, with very little change in torsion. Titanium plates reduced uninstrumented ACDF ROM by 69% in flexion-extension, 45% in lateral bending, and 27% in torsion. Differences between bioresorbable and titanium plates were significant in flexion-extension and lateral bending. Cyclic loading did not significantly change ROM for either plate. More moment was shared in lateral bending by the spine/graft with bioresorbable plates (78%) compared with titanium plating (63%). Bioresorbable plates contained an intervertebral graft, provided some stabilization, remained intact throughout the simulated immediate postoperative loading, and shared more load with the graft and

  5. MyPlate Food Guide

    Science.gov (United States)

    ... Can I Help a Friend Who Cuts? MyPlate Food Guide KidsHealth > For Teens > MyPlate Food Guide Print ... other sugary drinks. Avoid oversized portions. continue Five Food Groups Different food groups meet different nutrition needs. ...

  6. ELAF failed fuel plate examination

    International Nuclear Information System (INIS)

    A fuel plate examination was conducted in the hot cell and canal to determine the possible failure modes for three plates leaking fission products. The plates were irradiated in the Extended Life Aluminide Fuel (ELAF) program in support of university research reactor goals to increase the limits presently allowed. The examination indicated pitting corrosion to be the failure mode. Other failure modes such as: (a) nonbonded swelling, (b) excessive fuel swelling, and (c) overheating of the plates were not observed

  7. Flow around a flexible plate in a free stream

    International Nuclear Information System (INIS)

    This paper presents a numerical scheme for fluid-structure interaction, especially for flexible structures. The lattice Boltzmann method with an immersed boundary technique using a direct forcing scheme is used for the fluid , and a finite element method with Euler beam elements is used for the flexible plate. The direct forcing scheme of the lattice Boltzmann method was improved for the immersed boundary scheme by introducing the occupation ratio of fluid lattices among the interpolated lattices. We compared the results of our proposed scheme with the known results of conventional schemes. Using the proposed numerical scheme, the flow around the flexible plate in a free stream is simulated for the effect of flexibility. Our results show that the major role of the flexibility of the flexible plate is the reduction of the resistance from flow. From the unsteady flow around a flexible plate, we found that the St of the flexible plate up to Re 120 was dependent on plate flexibility. In the range of Re > 120 , the St of very flexible plate increased with increasing Re, while the St of rigid plate decreased with increasing Re

  8. Fleroxacin resistance in Escherichia coli.

    OpenAIRE

    Chapman, J S; Bertasso, A; Georgopapadakou, N H

    1989-01-01

    Spontaneous fleroxacin-resistant mutants of Escherichia coli K-12 were isolated at a frequency of 10(-10) to 10(-11) mutants per CFU plated. All mutants exhibited quinolone-resistant replicative DNA biosynthesis, and 4 of 11 mutants also had decreased amounts of OmpF or OmpC porin. None of the mutants had changes solely in porin proteins.

  9. High voltage pickup plate

    International Nuclear Information System (INIS)

    For the 'electron gun' of the NIKHEF electron accelerator a High Voltage Pickup Plate (HVPP) has been constructed with belonging electronics, in order to iinvestigate the stability of the voltage of the electron gun. With the HVPP it is possible to measure the absolute quantities of the instabilities, as result of the rectifying and the pulsed load, of the ICT. (author). 28 figs.; 1 tab

  10. Plates with Incompatible Prestrain

    Science.gov (United States)

    Bhattacharya, Kaushik; Lewicka, Marta; Schäffner, Mathias

    2016-07-01

    We study effective elastic behavior of the incompatibly prestrained thin plates, where the prestrain is independent of thickness and uniform through the plate's thickness h. We model such plates as three-dimensional elastic bodies with a prescribed pointwise stress-free state characterized by a Riemannian metric G, and seek the limiting behavior as {h to 0}. We first establish that when the energy per volume scales as the second power of h, the resulting {Γ} -limit is a Kirchhoff-type bending theory. We then show the somewhat surprising result that there exist non-immersible metrics G for whom the infimum energy (per volume) scales smaller than h 2. This implies that the minimizing sequence of deformations carries nontrivial residual three-dimensional energy but it has zero bending energy as seen from the limit Kirchhoff theory perspective. Another implication is that other asymptotic scenarios are valid in appropriate smaller scaling regimes of energy. We characterize the metrics G with the above property, showing that the zero bending energy in the Kirchhoff limit occurs if and only if the Riemann curvatures R 1213, R 1223 and R 1212 of G vanish identically. We illustrate our findings with examples; of particular interest is an example where {G_{2 × 2}}, the two-dimensional restriction of G, is flat but the plate still exhibits the energy scaling of the Föppl-von Kármán type. Finally, we apply these results to a model of nematic glass, including a characterization of the condition when the metric is immersible, for {G = Id3 + γ n ⊗ n} given in terms of the inhomogeneous unit director field distribution { n in R^3}.

  11. New plates for different types of plate heat exchangers

    OpenAIRE

    Fernandes, Carla S.; Dias, Ricardo P.; João M. Maia

    2008-01-01

    The first patent for a plate heat exchanger was granted in 1878 to Albretch Dracke, a German inventor. The commercial embodiment of these equipments has become available in 1923. However, the plate heat exchanger development race began in the 1930’s and these gasketed plate and frame heat exchangers were mainly used as pasteurizers (e.g. for milk and beer). Industrial plate heat exchangers were introduced in the 1950’s and initially they were converted dairy models. Brazed plate heat exchange...

  12. The Studies of Composite Electroless Plating Process on Sintering Ndfeb Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    HUJian-wen; MAJing; YANDong-qing; GAOQing; MENGYong-qiang

    2004-01-01

    A reasonable pre-treatment and an ultrasonic pre-plating Cu film were applied for sintering NdFeB permanent magnet. The samples were then plated in neutral bath (PH=7) for 40rnin and in acidic bath (PH=4.8-5.1) for 2h. A composite electroless plating with different phosphor content was obtained. The results show that the composite plating coatings are dense and have a strong bond with the substrate, which contribute to the excellent corrosion resistance of the plating coating.

  13. The Studies of Composite Electroless Plating Process on Sintering Ndfeb Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    HU Jian-wen; MA Jing; YAN Dong-qing; GAO Qing; MENG Yong-qiang

    2004-01-01

    A reasonable pre-treatment and an ultrasonic pre-plating Cu film were applied for sintering NdFeB permanent magnet. The samples were then plated in neutral bath (PH=7) for 40min and in acidic bath (PH=4.8~5.1) for 2h. A composite electroless plating with different phosphor content was obtained. The results show that the composite plating coatings are dense and have a strong bond with the substrate, which contribute to the excellent corrosion resistance of the plating coating.

  14. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact : Experimental Investigation II

    Directory of Open Access Journals (Sweden)

    S. N. Dikshit

    1999-07-01

    Full Text Available The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° obliquity, the plate offers protection up to a striking velocity of 800 mls. At zero obliquity, the plate provides protection below 6~ m/s. The depth of penetration decreases with increasing obliquity. The plate resistance does not decrease at higher obliquity observed in an earlier work.

  15. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1997-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisaton of the damage, which deve...

  16. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisation of the damage, which dev...

  17. MyPlate Daily Checklist

    Science.gov (United States)

    ... MyPlate What Is MyPlate? Fruits All About the Fruit Group Nutrients and Health Benefits Tips to Help You Eat Fruits Food ... Updated: Jul 22, 2016 RESOURCES FOR NUTRITION AND HEALTH MYPLATE What Is MyPlate? Fruits Vegetables Grains Protein Foods Dairy Oils ONLINE TOOLS ...

  18. THE NEW STRUCTURE OF A PLATE-PILE FOUNDATION

    Directory of Open Access Journals (Sweden)

    SAMORODOV О. V.

    2016-01-01

    Full Text Available Raising of problem. In the construction of high-rise buildings with significant loads on foundations and bedding at the base of not rocky soils tend to use the most common pile foundation to reduce the deformation and correspond to regulations [1] on the maximum permissible deformation. Monitoring of the stress-strain state (SSS pile foundations constructed buildings shows the existing reserves of bearing capacity on the one hand - soil bases of the second group of limit states, on the other - the foundation of the first group of limit states by regulating the SSS foundation during construction and exploitation. Therefore, are increasingly using more progressive structure of foundations consisting of piles and of plate, as well as methods for their construction [2 - 10], however, in their design there are a number of disadvantages associated with the ambiguity of the application of methods for the calculation of such structures, which allows to do only partial conclusions and recommendations. Purpose. Is proposing the new structure of a plate-pile foundation, which overcomes the drawbacks of the existing design solutions and methods of consruction their, as well as is proposing an engineering method of a determination of basic parameters. Conclusion. Is proposes the new structure of a plate-pile foundation and the method of a determination of basic parameters his in the design of a soil base to the maximum permissible deformation Su buildings. Efficiency of application this type plate-pile foundation obtained by rational distribution resistance between a plate and piles, when under load from the building to the first work fully incorporated plate that allows maximum deformed for plate, and then the piles - due to of the hinge connection with the plate. Thus, depending on the maximum permissible deformation for buildings resistance of plate part of a full load of more than 50%, that significantly reduces the consumption of concrete.

  19. Study of uranium plating measurement

    International Nuclear Information System (INIS)

    In neutron physics experiments, the measurement for plate-thickness of uranium can directly affect uncertainties of experiment results. To measure the plate-thickness of transform target (enriched uranium plating and depleted uranium plating), the back to back ionization chamber, small solid angle device and Au-Si surface barrier semi-conductor, were used in the experiment study. Also, the uncertainties in the experiment were analyzed. Because the inhomo-geneous of uranium lay of plate can quantitively affect the result, the homogeneity of uranium lay is checked, the experiment result reflects the homogeneity of uranium lay is good. (authors)

  20. Vehicle License Plate Recognition Syst

    Directory of Open Access Journals (Sweden)

    Meenakshi,R. B. Dubey

    2012-12-01

    Full Text Available The vehicle license plate recognition system has greater efficiency for vehicle monitoring in automatic zone access control. This Plate recognition system will avoid special tags, since all vehicles possess a unique registration number plate. A number of techniques have been used for car plate characters recognition. This system uses neural network character recognition and pattern matching of characters as two character recognition techniques. In this approach multilayer feed-forward back-propagation algorithm is used. The performance of the proposed algorithm has been tested on several car plates and provides very satisfactory results.

  1. Vehicle License Plate Recognition System

    Directory of Open Access Journals (Sweden)

    Meenakshi

    2012-12-01

    Full Text Available The vehicle license plate recognition system has greater efficiency for vehicle monitoring in automatic zone access control. This Plate recognition system will avoid special tags, since all vehicles possess a unique registration number plate. A number of techniques have been used for car plate characters recognition. This system uses neural network character recognition and pattern matching of characters as two character recognition techniques. In this approach multilayer feed-forward back-propagation algorithm is used. The performance of the proposed algorithm has been tested on several car plates and provides very satisfactory results.

  2. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  3. Temperature field of steel plate cooling process after plate rolling

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Full Text Available Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

  4. Thermal buckling analysis of truss-core sandwich plates

    Institute of Scientific and Technical Information of China (English)

    陈继伟; 刘咏泉; 刘伟; 苏先樾

    2013-01-01

    Truss-core sandwich plates have received much attention in virtue of the high values of strength-to-weight and stiffness-to-weight as well as the great ability of impulse-resistance recently. It is necessary to study the stability of sandwich panels under the influence of the thermal load. However, the sandwich plates are such complex three-dimensional (3D) systems that direct analytical solutions do not exist, and the finite element method (FEM) cannot represent the relationship between structural parameters and mechanical properties well. In this paper, an equivalent homogeneous continuous plate is idealized by obtaining the effective bending and transverse shear stiffness based on the characteristics of periodically distributed unit cells. The first order shear deformation theory for plates is used to derive the stability equation. The buckling temperature of a simply supported sandwich plate is given and verified by the FEM. The effect of related parameters on mechanical properties is investigated. The geometric parameters of the unit cell are optimized to attain the maximum buckling temperature. It is shown that the optimized sandwich plate can improve the resistance to thermal buckling significantly.

  5. [Deductive inference on the plate height equation of electrochromatography].

    Science.gov (United States)

    Dai, C Z

    1999-11-01

    In this paper, the dynamic process of electrochromatography has been studied. The differences between electrochromatography and high performance liquid chromatography have been compared. The author considers that because of the effects of electroendosmosis flow at the surface and interior of stationary phase particles, the plate height increment due to axial dispersion of the eluite in the interstitial space and the intraparticular diffusion resistance to mass transfer will reduce, and the "film" resistance at the particle boundery will disappear. But when a current passes along the electrochromatographic column Ohmic heat releases and the tube will be heated up. The temperature difference between the center of tube and the tube wall will affect the plate height. The plate height contribution from this is quite significant and can seriously reduce the efficiency of column. Thus, a general plate height equation has been derived to express the effect of axial dispersion in the electrochromatographic process, mass transfer resistances at the mobile phase, kinetic resistances associated with the reversible binding of eluite by the stationary phase and the temperature distribution effect. According to these theories, the plate height equation of electrochromatography has been obtained as following: [formula: see text] It is suggested that there exist a lot of factors which influence the column efficiency of electrochromatography, such as axial dispersion in the interstitial space, mass transfer resistances at the mobile phase, kinetic resistances with the reversible binding of eluite by the stationary phase, and the temperature field in the column inside. The influence of temperature field is closely related with internal diameter of column. PMID:12552679

  6. Ultrafast microchannel plate photomultipliers.

    Science.gov (United States)

    Kume, H; Koyama, K; Nakatsugawa, K; Suzuki, S; Fatlowitz, D

    1988-03-15

    Performance characteristics of several new types of photomultiplier tubes (PMT) with microchannel plates (MCP) are presented in this paper. They are the MCP-PMT with 6-microm diam channels, MCP-PMT with an S-l photocathode, and MCP-PMT with multi (discrete) anode and gatable MCP-PMT. Important requirements of an optical detector for picosecond lasers, fluorescence measurements, and material analysis are low light detectability, ultrafast time response, and versatile operation including modulation. The basic configuration, characteristics, and practical results of these detectors are described. PMID:20531532

  7. Plate Full of Color

    Centers for Disease Control (CDC) Podcasts

    2008-08-04

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Plate Full of Color teaches the value of eating a variety of colorful and healthy foods.  Created: 8/4/2008 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/5/2008.

  8. Study on Heat Resistant Waterborne Pressure-sensitive Adhesive for the Hot-melt Type Automobile Damping Plate%水性耐高温汽车阻尼板用压敏胶研究

    Institute of Scientific and Technical Information of China (English)

    刘威胜; 曾婉玲; 田巧

    2015-01-01

    以丙烯酸丁酯,甲基丙烯酸甲酯,丙烯酸,N-羟甲基丙烯酰胺为主要原料,过硫酸铵为引发剂,采用了种子乳液聚合法合成水性丙烯酸酯压敏胶。研究了软硬单体,功能单体,乳化剂,反应温度和聚合工艺对压敏胶性能的影响,并成功制备水性耐高温汽车阻尼板用压敏胶。%Abstact:The acrylate pressure-sensitive adhesive was prepared using butyl acrylate, methyl methacrylate and acrylic acid as main materials, ammonium persulfate as the initiator by seeded emulsion polymerization. The influences of the reactive monomer, the functional monomer, emulsifier, initiator and the polymerization process were investigated and the emulsion PSA ( pressure-sensitive adhesive) used for automobile damping plate was synthesized.

  9. Optical modulation of terahertz pulses in a parallel plate waveguide

    DEFF Research Database (Denmark)

    Cooke, David; Jepsen, Peter Uhd

    2008-01-01

    In this work we present a technique for optically modulating a terahertz pulse inside a parallel plate waveguide. A novel semiconductor filled waveguide is formed by coating both sides of a thin, high resistivity silicon slab with a transparent conducting oxide. While the waveguide is intrinsically...

  10. Durable Bipolar Plates For Lead/Acid Batteries

    Science.gov (United States)

    Clough, Thomas J.; Pinsky, Naum

    1990-01-01

    New structure for positive faces of bipolar plates increases longevity of lead/acid batteries. Divides positive-electrode layer into many isolated segments so defects cannot spread across layer. Surfaces treated before assembly to promote adhesion. Ridges on body divide possible electrode into isolated squares, each typically 1 in. on side. Materials supporting electrochemically active components lightweight and resistant to acid.

  11. Improvements of Nickel Deposit Characteristics by Pulse Plating

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Leisner, Peter; Møller, Per

    1993-01-01

    Investigation of the properties of electroplated nickel, using both pulse plating and conventional di-rect current (DC), has lead to several interesting improvements of deposit characteristics. Investigated properties include; internal stress, tensile strength, yield stress, elongation, hardness......, throwing power, current efficiency and corrosion resistance (porosity). Experiments have been made with Watts nickel baths, sulphamate baths and a modified Watts bath called W3....

  12. Nickel Coatings and Electroforming Using Pulse Reversal Plating

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Dylmer, Henrik; Møller, Per

    1995-01-01

    -mechanics. A series of new results using pulse reversal plating in Watts based electrolytes will be discussed. Elec-troforming completely without internal stress and with improved throwing power will be demonstrated, as well as a corrosion resistance of nickel coatings that could allow coating thicknesses, as...

  13. Minimum wall pressure coefficient of orifice plate energy dissipater

    Directory of Open Access Journals (Sweden)

    Wan-zheng AI

    2015-01-01

    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  14. Corrosion Resistance of TiN and CrN Coatings with Arc Ion Plating on 201 Stainless Steel Surface%201不锈钢表面弧光离子镀TiN和CrN薄膜的耐蚀性

    Institute of Scientific and Technical Information of China (English)

    马志康; 高原; 蔡航伟; 王成磊; 袁琳; 张焱; 吴炜钦

    2013-01-01

    利用弧光离子镀设备,对201不锈钢表面进行离子沉积TiN薄膜和CrN薄膜.分别在3.5% NaCl溶液、1 mol·L-1NaOH溶液和1 mol·L-1 H2SO4溶液中进行电化学腐蚀性能测试.结果表明,通过弧光离子镀技术在201不锈钢表面分别形成了厚度为1.2 μm的致密TiN薄膜和3μm的致密CrN薄膜;201不锈钢、TiN薄膜和CrN薄膜在3.5%的NaCl溶液中耐蚀性相当;在1mol·L-1的NaOH溶液中,TiN薄膜的耐蚀性约是201不锈钢的2倍,CrN薄膜的耐蚀性是201不锈钢的24倍,TiN薄膜的12倍;在1mol·L-1的H2SO4溶液中,TiN薄膜和CrN薄膜的耐蚀性相比201不锈钢分别提高20倍和26倍.%201 stainless steel was plated with TiN and CrN coatings by arc ion plating.Electrochemical corrosion was tested in 3.5% NaCl solution,1 mol · L-1 NaOH solution and 1 mol · L-1 H2SO4 solution.The results show that 1.2 μm dense TiN coatings and 3μm dense CrN coatings were respectively formed by arc ion plating on the surface of the 201 stainless steel.In 3.5% NaCl solution,the corrosion resistance of TiN coatings and CrN coatings are equitement to that of 201 stainless steel.In 1 mol · L-1 NaOH solution,the corrosion resistance of the TiN coatings was twice of 201 stainless steel.The corrosion resistance of the CrN coatings was about 24 times of 201 stainless steel and 12 times of TiN coatings.In 1 mol · L-1 H2SO4 solution,the corrosion resistance of TiN coatings and CrN coatings strengthen 20 times and 26 times of 201 stainless steel,respectively.

  15. Plating on difficult-to-plate metals: what's new

    International Nuclear Information System (INIS)

    Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required

  16. Detection of inducible clindamycin resistance applications in Staphylococcus by microScan gram-positive bacteria composite plate%MicroScan革兰阳性复合板检测葡萄球菌属诱导型克林霉素耐药的应用

    Institute of Scientific and Technical Information of China (English)

    傅石明

    2012-01-01

    目的 评价MicroScan革兰阳性复合板检测葡萄球菌属诱导型克林霉素耐药的临床应用价值.方法 用MicroScan微生物鉴定药敏分析仪检测203株葡萄球菌属细菌对克林霉素和红霉素的耐药性;在做药敏鉴定的同时,用已灭菌的微量加样器吸取1 μg/ml克林霉素孔55 μl菌液弃去,再吸取红霉素4μg/ml孔菌液55μl于1 μg/ml克林霉素孔检测诱导克林霉素耐药;每株细菌均以双纸片法D-试验作对照.结果 203株葡萄球菌属中有86株对红霉素耐药而克林霉素敏感,占42.4%;其中D-试验阳性54株,诱导型克林霉素耐药菌株的检出率为62.8%;D试验阳性菌株MicroScan革兰阳性复合板检测53株阳性,两者符合率为98.8%.结论 MicroScan革兰阳性复合板可直接检测诱导克林霉素耐药.%OBJECTIVE To evaluate the clinical value of the detection of inducible clindamycin resistance in Staphylococcus by MicroScan gram-positive bacteria composite plate. METHODS MicroScan semi-automatic identification and drug susceptibility analyzer was adopted in the bacteria detection of clindamycin and erythromycin resistance of 203 Staphylococcus bacteria in our hospital; while doing the susceptibility test, a sterilized micropipette was used to extract and throw away 1μg/ml bacterium erythromycin 55 ul, and to extract 4μg/ml bacterium erythromycin 55μl to detect the inducible clindamycin resistance with the remain bacterium erythromycin. D-test method was performed on each strain as a control. RESULTS Among 203, 86 pairs of Staphylococcus were resistant to erythromycin and sensitive to clindamycin, accounting for 42. 4%. 54 pairs were D-test positive, and the detection rate of inducible clindamycin resistant strains was 62. 8%. 53 D-test positive strains were detected positive by MicroScan gram-positive composite panels. Both results were in line with a coincidence rate 98. 8%. CONCLUSION MicroScan gram-positive composite plate can be used

  17. Quantitative computed tomography as a test of endurance for evaluation of bony plates

    International Nuclear Information System (INIS)

    Quantitative computed tomography was used to determine the radiodensity of bony plates. The CT scans provided information regarding radiodensity of bony plates and allowed to verify the uniformity of bone mineral density in their scope. The proposed methodology should be considered as another tool for determining the resistance of these biomaterials. (author)

  18. Unsteady interaction of plates and shells with continuous medium under explosive waves

    International Nuclear Information System (INIS)

    In this paper, a brief introduction to unsteady interaction of plates and shells with continuous medium under explosive waves is given. The additional mass and resistance are treated as equivalent loads, then the dynamic response of plates is analysed by using dynamic influence coefficient method. Numerical results are given

  19. The trigger of the ALICE dimuon arm architecture and detectors

    CERN Document Server

    Arnaldi, R; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; Dellacasa, G; De Marco, N; Dupieux, P; Espagnon, B; Fargeix, J; Gallio, M; Lamoine, L; Luquin, Lionel; Manso, F; Métivier, V; Musso, A; Piccotti, A; Rahmani, A; Ramillien, V; Royer, L; Roig, O; Scalas, E; Scomparin, E; Vercellin, Ermanno

    1999-01-01

    The trigger system of the ALICE dimuon arm is based on resistive plate chambers (RPC). Besides a short description of the trigger system, the test results of a RPC prototype with electrodes made of low resistivity bakelite ( equivalent to 3.10/sup 9/ Omega .cm) are presented. Rate capability, time resolution and cluster size have been measured for the RPC operated both in streamer and in avalanche mode. Although the rate capability is obviously higher in avalanche mode (few kHz/cm/sup 2/), remarkable results have been achieved even in streamer mode (several hundreds of Hz/cm/sup 2/). (6 refs).

  20. Tectonics of the Easter plate

    Science.gov (United States)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  1. Dissolution of HFIR control plates

    International Nuclear Information System (INIS)

    A process was developed for the dissolution of High Flux Isotope Reactor (HFIR) control plates. These plates consist of aluminum metal, intensely radioactive europium oxide, and a small amount of tantalum metal. The radioactive solution will be diluted, mixed with grout, and disposed of by shale fracture. The plates are dissolved in nitric acid using a mercury catalyst. Conditions were determined that would produce a reaction rate compatible with existing equipment. 3 references, 1 figure, 3 tables

  2. Use of antireflection layers to avoid ghost plating on Ni/Cu plated crystalline silicon solar cells

    Science.gov (United States)

    Jeong, Myeong Sang; Choi, Sung Jin; Chang, Hyo Sik; In Lee, Jeong; Kang, Min Gu; Kim, Donghwan; Song, Hee-eun

    2016-03-01

    Screen printing is a method commonly used for making electrodes for crystalline silicon solar cells. Although the screen-printing method is fast and easy, screen-printed electrodes have a porous structure, high contact resistance, and low aspect ratio. On the other hand, plated electrodes have low contact resistance and narrow electrode width. Therefore, the plating method could be substituted for the screen-printing method in crystalline silicon solar cells. During the plating process, ghost plating can appear at the surface when the quality of the passivation layer is poor, causing an increase in the recombination rate. In this paper, light-induced plating was applied to the fabrication of electrodes, and various passivation layers were investigated to remove ghost plating in crystalline silicon solar cells. These included, (1) SiNx deposited by plasma-enhanced chemical vapor deposition (PECVD), (2) a double SiNx layer formed by PECVD, (3) a double layer with thermal silicon oxide and SiNx deposited by PECVD, and (4) a double layer comprising SiNx and SiOx formed by PECVD. For the plated solar cells, a laser was used to remove various antireflection coating (ARC) layers and phosphoric acid was spin-coated onto the doped silicon wafer prior to laser ablation. Also, a screen-printed solar cell was fabricated to compare plated solar cells with screen-printed solar cells. As a result, we found that a thermal SiO2/PECVD SiNx layer showed the lowest pinhole density and its wet vapor transmission rate was characterized. The solar cell with the thermal SiO2/PECVD SiNx layer showed the lowest J02 value, as well as improved Voc and Jsc.

  3. Plate heat exchanger

    International Nuclear Information System (INIS)

    The plate exchanger described includes a series of individual modules joined together, communicating in pairs to delimit two flow circuits separated by two fluids mutually exchanging calories. Each module includes at least one flat frame around a central cavity, at least two apertures made in the frame respectively for the inlet and oulet of the fluids crossing the cavity and at least one opening in the frame for the fluids to pass to a neighbouring module. The frames of the modules form a stack plane upon plane and are isolated by a thin leak-tight sheet parallel to the plane of the frames and separating the fluid substances in two superimposed frames. The heat transfer between these fluids occurs through this thin sheet from one module to the next in the stack

  4. Multichip on Aluminum Metal Plate Technology for High Power LED Packaging

    Institute of Scientific and Technical Information of China (English)

    Choong-mo NAM; Mi-hee JI

    2010-01-01

    Multichip on Aluminum Metal Plate(MOAMP) technology with simple structure and low thermal resistance is developed for effective heat removal of Light Emitting Diode(LED) p-n junction and LED lighting module to have high reliability. The thermal resistance of LED modules was numerical and experimental. Thermal resistance from the junction to aluminum metal plate, considering input power of LED module using MOAMP technology, is 3.02 K/W, 3.23 K/W for the measured and calculated, respectively. We expect that the reported MOAMP technology with low thermal resistance will be a promising solution for high power LED lighting modules.

  5. Plate osteosynthesis of simple forearm fractures : LCP versus DC plates

    NARCIS (Netherlands)

    Stevens, Charles Tjerk; Ten Duis, Henk Jan

    2008-01-01

    The aim of this study was to compare the time to radiological bony union of simple A-type fractures of the forearm, treated with either a locking compression plate (LCP) or a dynamic compression plate (DCP). For each fracture, the relation between the use of compression and radiological healing time

  6. PEM燃料电池双极板与气体扩散层界面接触电阻测量与模拟%Measurement and Simulation of Contact Resistance Between Bipolar Plate and Gas Diffusion Layer in PEM Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    李果; 谈金祝; 巩建鸣

    2011-01-01

    质子交换膜(proton exchange membrane,PEM)燃料电池中双极板(Bipolar plate,BPP)与气体扩散层(Gas diffusion layer,GDL)界面接触电阻对燃料电池电化学性能有着重要影响,而螺栓夹紧力又是影响接触电阻的关键因素之一.因此,针对PEM燃料电池中的双极板与气体扩散层,采用试验和有限元模拟相结合的方法研究螺栓夹紧力对接触电阻的影响.结果表明,随着螺栓夹紧力的增加,双极板与气体扩散层界面接触电阻呈下降趋势,起初下降较快,然后下降逐步平缓.基于有限元软件ABAQUS开发一个力一电耦合程序预测得到了双极板与气体扩散层界面接触电阻,其结果与试验结果吻合较好.同时采用有限元法分析螺栓夹紧力对气体扩散层孔隙率变化的影响.结果表明,随着螺栓夹紧力的增加,气体扩散层孔隙率降低,特别是双极板与气体扩散层接触圆角区域,下降最为明显.%The contact resistance between bipolar plate (BPP) and gas diffusion layer (GDL) has a significant effect on the electric-chemical performance of the proton exchange membrane (PEM) fuel cell. The applied force on each of bolts in PEM fuel cell assembly is critical to the contact resistance between BPP and GDL for the PEM fuel cell. So the contact resistance between the BPP and the GDL is studied by using both experimental and finite element methods. The test results show that the contact resistance decreases with the increase of the clamping force quickly at first , and then gently. Based on the code ABAQUS, a coupled mechanical-electric procedure is developed. And then, the finite element method (FEM) is used to predict the contact resistance between the BPP and GDL under various clamping forces. The FEM results are in good agreement with the experimental results. In addition, the effect of the clamping force on the porosity of the GDL is analyzed by using FEM. The results indicate that the porosity decreases with the

  7. Plate tectonics, damage and inheritance.

    Science.gov (United States)

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates. PMID:24717430

  8. Stepped conical zone plate antenna

    Science.gov (United States)

    Wiltse, James C.

    2001-07-01

    The Fresnel zone plate lens was invented and developed for optical frequencies. However, fabrication difficulties at the short optical wavelengths have prevented obtain good efficiencies. At longer microwave or millimeter-wavelengths fabrication is easier and phase correcting zone plate antennas have been used to obtain good efficiencies. This paper describes a new type of phase correcting zone plate having even better efficiency, namely a diffraction efficiency of 99 percent compared to a true lens, and an overall efficiency much better than a true lens. For the usual zone plate antenna employed at microwave or millimeter wavelengths, path length adjustment is accomplished by cutting different depths in a dielectric plate or by using two or more dielectrics having different dielectric constants. The new design uses a tilted cut in a dielectric plate, which more accurately matches the shape of a true lens and produces much lower phase error. The construction is still near and can be made for example, by a milling machine with a tilted bit. For a circular zone plate, the lens is a stepped conical or tapered shape. Because the phase steps are small, the far-field antenna pattern is excellent and sidelobe-levels are very low. Analysis of typical configurations will be given, showing that phase errors are small, lower than those for an eighth-wave corrected phase zone plate.

  9. Fresnel zone plate coded imaging

    International Nuclear Information System (INIS)

    The author introduced the principle of the Fresnel-zone-plate coded imaging, and design a Fresnel zone plate coded image camera with high spatial resolution. A experimental simulation with two-aperture visible light source is made. The result shows that this coded image camera can reveal the source distribution truly

  10. ChooseMyPlate.gov

    Science.gov (United States)

    ... MyPlate What Is MyPlate? Fruits All About the Fruit Group Nutrients and Health Benefits Tips to Help You Eat Fruits Food ... cup, or in your bowl. All about the Fruit Group Nutrients and health benefits Tips to making wise choices VIEW FOOD ...

  11. Micro-channel plate detector

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  12. SAMI Automated Plug Plate Configuration

    CERN Document Server

    Lorente, Nuria P F; Goodwin, Michael

    2012-01-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13 x 61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

  13. Application of Laser Ranging and VLBI Data to a Study of Plate Tectonic Driving Forces

    Science.gov (United States)

    Solomon, S. C.

    1980-01-01

    The conditions under which changes in plate driving or resistive forces associated with plate boundary earthquakes are measurable with laser ranging or very long base interferometry were investigated. Aspects of plate forces that can be characterized by such measurements were identified. Analytic solutions for two dimensional stress diffusion in a viscoelastic plate following earthquake faulting on a finite fault, finite element solutions for three dimensional stress diffusion in a viscoelastic Earth following earthquake faulting, and quantitative constraints from modeling of global intraplate stress on the magnitude of deviatoric stress in the lithosphere are among the topics discussed.

  14. Anchor Plates in Two-Layered Cohesion Less Soils

    Directory of Open Access Journals (Sweden)

    Hamed Niroumand

    2010-01-01

    Full Text Available Problem statement: During the past few years a great number of experimental model and numerical analysis results on the uplift resistance of anchor plate embedded in homogeneous cohesion less soil has been reported by many researchers. A review of related literature shows that not much research has been done to analyze the performance of anchor plates in layered soils a problem, which is often encountered by the professional engineers in the field. Approach: This study presented the performance of the anchor plates in the cohesion less soil by different researchers. It was based on different previous researches, from the earliest till the most recent ones. The main aim of this research was focused on the prediction of the anchor plates behavior and the force in the layered cohesion less soils. Few laboratory studies were conducted to investigate the uplift capacity behavior of cohesion less soil by previous researchers. Results: The experimental and numerical investigation included uplift test on cohesion less soil by last researchers. The embedment ratio and the effect of density on uplift response were evaluated. This analysis was investigated experimentally and numerically behavior of anchor plates buried in two layered cohesion less soil. Although earlier researchers developed experimentally expressions to estimate the uplift capacity of irregular anchor plates in layered cohesion less soils. Conclusion: The study observed that the ultimate uplift capacity is dependent on the relative strength of the two layers, the depth ratio of embedment and the upper layer thickness ratio.

  15. Slender Compressed Plate in Component Based Finite Element Model

    Science.gov (United States)

    Kurejková, M.; Wald, F.; Kabeláč, J.; Šabatka, L.

    2015-11-01

    The paper presents an advance design model of a slender plate in the structural steel joint. Finite element methods and material models are described and design procedure for slender plates in numerical models of steel joints is proposed. The design procedure is demonstrated on examples. The results are verified with an analytical model according to European standards. A compressed beam with slender web and beam-to-column joint are studied by numerical analysis, buckling resistances are determined and results verified. The verification shows very good agreement.

  16. An asymmetric optical vortex generated by a spiral refractive plate

    Science.gov (United States)

    Kotlyar, V. V.; Kovalev, A. A.; Stafeev, S. S.; Nalimov, A. G.

    2013-02-01

    Using a revised Kirchhoff diffraction integral and the finite-difference time-domain method we show that an optical vortex generated by a refractive spiral plate with a relief step has an asymmetric profile. The annular diffraction pattern in the optical vortex beam cross-section is found to be disturbed not only for near-field diffraction but also for the Fresnel zone. For a spiral phase plate with topological charge 3, fabricated on a resist, optical vortex asymmetry has been shown experimentally by near-field scanning optical microscopy.

  17. An asymmetric optical vortex generated by a spiral refractive plate

    International Nuclear Information System (INIS)

    Using a revised Kirchhoff diffraction integral and the finite-difference time-domain method we show that an optical vortex generated by a refractive spiral plate with a relief step has an asymmetric profile. The annular diffraction pattern in the optical vortex beam cross-section is found to be disturbed not only for near-field diffraction but also for the Fresnel zone. For a spiral phase plate with topological charge 3, fabricated on a resist, optical vortex asymmetry has been shown experimentally by near-field scanning optical microscopy. (paper)

  18. Constraining porosity of the shallow forearc and plate interface offshore Nicaragua with marine electromagnetic data

    Science.gov (United States)

    Naif, S.; Key, K.; Constable, S.; Evans, R. L.

    2015-12-01

    We imaged the electrical resistivity structure of the incoming plate and outer forearc across the Middle America Trench with 2-D inversion of marine controlled-source electromagnetic data. The inverted data reveal a high conductivity channel that is congruent with the geometry of the plate interface, which we infer to be subducted sediments. We used the resistivity model to estimate the porosity of the upper plate and underthrust sediments. The sediment porosity decays exponentially as it is subducted along the plate interface, in good agreement with existing constraints from compaction studies. The plate interface is overlain by an upper plate that is one to two orders of magnitude more resistive, requiring low porosities (<15%) that are consistent with a non-accreting margin composed of crystalline basement or lithified sediments.At 18 to 23 km landward of the trench, the conductive channel diverges from the plate interface and extends 1-2 km into the overlying plate below a cluster of active seafloor seeps. The location of the anomaly at depth is synonymous with a rapid steepening of the seafloor slope. The steepened slope occurs at 15 to 25 km landward of the trench and is extensive, persisting for more than 100 km along the margin. This correlation leads us to conclude that the cause of the conductive feature is sediment underplating. The implications for the 1992 tsunami earthquake will be discussed.

  19. 2mm厚1000MPa级双相钢板电阻点焊工艺参数的优化%Optimization of Resistance Spot Welding Parameters of 1 000 MPa Grade Dual-Phase Steel Plate with Thickness of 2 mm

    Institute of Scientific and Technical Information of China (English)

    于燕; 陈军; 王敏; 王风雪

    2011-01-01

    对2mm厚国产汽车用1000MPa级双相钢板进行了不同工艺条件的电阻点焊,对各点焊接头显微组织、力学性能以及断口形貌等进行了分析,在此基础上优化了工艺参数。结果表明:在试验条件下,最佳点焊工艺参数为焊接电流12kA,焊接时间12周波(0.24s),焊接压力3.5kN;此条件下焊接接头的断裂方式以韧性断裂为主。%It was carried out that the resistance spot welding process with different conditions of the domestic 1 000 MPa grade dual-phase steel plate with thickness of 2 mm for automotive. The microstructure, mechanical properties of the weld seam and the fracture morphology were analyzed. The process parameters were optimized. The results show that the optimum welding process under the experimental conditions was obtained, which was welding current of 12 kA, welding time of 12 cyc (0. 24 s) and welding pressure of 3.5 kiN. And the fracture mode of the weld seam was main ductile fracture.

  20. Effectiveness of nickel plating in inhibiting atmospheric corrosion of copper alloy contacts

    Energy Technology Data Exchange (ETDEWEB)

    Ernest, T.; Sorensen, R.; Guilinger, T.

    1997-12-31

    A series of tests was run to determine the effect of Ni plating thickness on connector contact resistance. Copper coupons were plated with an electrolytic nickel strike followed by electroless nickel to produce Ni layers of 10, 20, 55 and 100 {micro}in. The coupons were then exposed to a simulated industrial environment. Pore corrosion was observed after the exposure, which correlated with Ni thickness. In a second series of tests, beryllium-copper four-tine contacts with 50 {micro}in of gold plate over electrolytic nickel strike/electroless-nickel plates of varying thickness were exposed the same corrosive environment. Contact resistance of mated pairs was monitored over a two-month period. The degradation in contact resistance correlated with the Ni thickness used in the connectors.

  1. Application of laser ranging and VLBI data to a study of plate tectonic driving forces. [finite element method

    Science.gov (United States)

    Solomon, S. C.

    1980-01-01

    The measurability of changes in plate driving or resistive forces associated with plate boundary earthquakes by laser rangefinding or VLBI is considered with emphasis on those aspects of plate forces that can be characterized by such measurements. Topics covered include: (1) analytic solutions for two dimensional stress diffusion in a plate following earthquake faulting on a finite fault; (2) two dimensional finite-element solutions for the global state of stress at the Earth's surface for possible plate driving forces; and (3) finite-element solutions for three dimensional stress diffusion in a viscoelastic Earth following earthquake faulting.

  2. Stability of Plates and Plated Structures - General Report

    Czech Academy of Sciences Publication Activity Database

    Maquoi, R.; Škaloud, Miroslav

    2000-01-01

    Roč. 55, 1-3 (2000), s. 45-68. ISSN 0143-974X. [Stability and Ductility of Steel Structures. Timisoara, 09.09.1999-11.09.1999] R&D Projects: GA ČR GA103/97/0002; GA AV ČR IAA2071701 Keywords : stability * plates * plated structures * web breathing * design Subject RIV: JM - Building Engineering Impact factor: 0.418, year: 2000

  3. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

    Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate

  4. Performance evaluation and characterization of metallic bipolar plates in a proton exchange membrane (PEM) fuel cell

    Science.gov (United States)

    Hung, Yue

    Bipolar plate and membrane electrode assembly (MEA) are the two most repeated components of a proton exchange membrane (PEM) fuel cell stack. Bipolar plates comprise more than 60% of the weight and account for 30% of the total cost of a fuel cell stack. The bipolar plates perform as current conductors between cells, provide conduits for reactant gases, facilitate water and thermal management through the cell, and constitute the backbone of a power stack. In addition, bipolar plates must have excellent corrosion resistance to withstand the highly corrosive environment inside the fuel cell, and they must maintain low interfacial contact resistance throughout the operation to achieve optimum power density output. Currently, commercial bipolar plates are made of graphite composites because of their relatively low interfacial contact resistance (ICR) and high corrosion resistance. However, graphite composite's manufacturability, permeability, and durability for shock and vibration are unfavorable in comparison to metals. Therefore, metals have been considered as a replacement material for graphite composite bipolar plates. Since bipolar plates must possess the combined advantages of both metals and graphite composites in the fuel cell technology, various methods and techniques are being developed to combat metallic corrosion and eliminate the passive layer formed on the metal surface that causes unacceptable power reduction and possible fouling of the catalyst and the electrolyte. The main objective of this study was to explore the possibility of producing efficient, cost-effective and durable metallic bipolar plates that were capable of functioning in the highly corrosive fuel cell environment. Bulk materials such as Poco graphite, graphite composite, SS310, SS316, incoloy 800, titanium carbide and zirconium carbide were investigated as potential bipolar plate materials. In this work, different alloys and compositions of chromium carbide coatings on aluminum and SS316

  5. The dynamics of plate tectonics and mantle flow: from local to global scales.

    Science.gov (United States)

    Stadler, Georg; Gurnis, Michael; Burstedde, Carsten; Wilcox, Lucas C; Alisic, Laura; Ghattas, Omar

    2010-08-27

    Plate tectonics is regulated by driving and resisting forces concentrated at plate boundaries, but observationally constrained high-resolution models of global mantle flow remain a computational challenge. We capitalized on advances in adaptive mesh refinement algorithms on parallel computers to simulate global mantle flow by incorporating plate motions, with individual plate margins resolved down to a scale of 1 kilometer. Back-arc extension and slab rollback are emergent consequences of slab descent in the upper mantle. Cold thermal anomalies within the lower mantle couple into oceanic plates through narrow high-viscosity slabs, altering the velocity of oceanic plates. Viscous dissipation within the bending lithosphere at trenches amounts to approximately 5 to 20% of the total dissipation through the entire lithosphere and mantle. PMID:20798311

  6. Experimental study and analysis of a novel multi-media plate heat exchanger

    Institute of Scientific and Technical Information of China (English)

    SONG JiWei; WANG Fei; CHENG Lin

    2012-01-01

    The experimental study and analysis of a novel multi-media plate heat exchanger were performed in this paper.This novel multi-media plate heat exchanger was self-developed during the process of the investigation and design of the alpha magnetic spectrometer (AMS) thermal system.The plate of this kind of novel plate heat exchanger is formed by discontinuous structure wave consisting of convex sphere and concave sphere,its heat transfer performance is better than that of the BRI chevron plate heat exchanger,and its resistance characteristics are superior to those of the nornally used 60-degree plate heat exchanger.Furthermore,the mechanism analysis of heat transfer enhancement shows that the spherical wave structure can reduce the local field synergy angle,so as to improve the field synergy degree of velocity vector and temperature gradient vector.

  7. 不锈钢双极板表面Cr与Cr2N镀层导电与耐蚀性研究%Improvement of Electric Conductivity and Corrosion-Resistance of Stainless Steel Bipolar Plates by Cr and Cr2N Coatings

    Institute of Scientific and Technical Information of China (English)

    肖宇; 顾大明; 刘峰; 李洪霞; 黄国胜; 李相波

    2013-01-01

    The 304 stainless steel bipolar plates, an important material for the proton exchange membrane fuel cell (PEMFC), were surface modified with the magnetron sputtered Cr and Gr2N coatings. The microstructures and properties of the Cr and Cr2N coatings were characterized with X-ray diffraction, Auger electron spectroscopy, scanning electron microscopy, and potentiodynamic polarization. The results show that the Cr2N coatings significantly improved the electric conductivity and corrosion resistance of the substrates. For instance, at a stack compacting pressure of the PEMFC, the contact resistance was found to be 20 mΩ·cm2, 70% lower than that of the substrate. In the simulated PEMFC environment, the corrosion potential increased by 300 mV, and the corrosion current density decreased by one order of magnitude, indicating a considerable enhancement of corrosion resistance.%采用等离子体磁控溅射的方法在304不锈钢双极板表面沉积出致密均匀的Cr层和Cr2N层.运用X射线衍射、俄歇电子能谱、扫描电镜、界面接触电阻测试和动电位极化等方法,研究了表面镀层对不锈钢双极板导电和耐腐蚀性能的影响.结果表明,经过镀氮化铬层后的双极板界面导电性能良好,在质子交换膜燃料电池(PEMFC)电堆装载压力下,界面接触电阻为20mΩ.cm2,与未镀层相比降低了约70%.双极板的耐腐蚀性能也有显著的增强:在模拟PEMFC环境中,腐蚀电位提高了约300mV,腐蚀电流降低了约1个数量级.

  8. What Are Growth Plate Injuries?

    Science.gov (United States)

    ... Submit this page to Yahoo! Buzz '); document.write(' Rank this page on Digg '); document.write(' Bookmark this ... to the knee. What Are Researchers Trying to Learn About Growth Plate Injuries? Researchers are searching for ...

  9. Plate shell structures of glass

    DEFF Research Database (Denmark)

    Bagger, Anne

    . Together with Ghent University, a script has been developed for an automated generation of a given plate shell geometry and a corresponding finite element (FE) model. A suitable FE modelling technique is proposed, suggesting a relatively simple method of modelling the connection detail's stiffness......This thesis is a study of plate shell structures -- a type of shell structure with a piecewise plane geometry, organized so that the load bearing system is constituted by distributed in-plane forces in the facets. The high stiffness-to-weight ratio of smoothly curved shell structures is mainly due...... to their curved shape. A plate shell structure maintains a high stiffness-to-weight ratio, while facilitating the use of plane structural elements. The study focuses on using laminated glass panes for the load bearing facets. Various methods of generating a plate shell geometry are suggested...

  10. Quaternions as astrometric plate constants

    Science.gov (United States)

    Jefferys, William H.

    1987-01-01

    A new method for solving problems in relative astrometry is proposed. In it, the relationship between the measured quantities and the components of the position vector of a star is modeled using quaternions, in effect replacing the plate constants of a standard four-plate-constant solution with the four components of a quaternion. The method allows a direct solution for the position vectors of the stars, and hence for the equatorial coordinates. Distortions, magnitude, and color effects are readily incorporated into the formalism, and the method is directly applicable to overlapping-plate problems. The advantages of the method include the simplicity of the resulting equations, their freedom from singularities, and the fact that trigonometric functions and tangential point transformations are not needed to model the plate material. A global solution over the entire sky is possible.

  11. Plate models and hidden informations

    International Nuclear Information System (INIS)

    A plate or a shell structure is mainly characterized by the fact that the thickness is small compared to the other dimensions. This allows some kinematical and constitutive approximations which can be justified in a mathematical framework as far as the energy of the model is concerned. But in most cases, the three dimensional local behaviour is not represented by the plate or the shell model. For instance, interlayer stresses in a multilayered plate can be singular and lead to a delamination. But they are not contained in a standard plate model. The local waves trapped in one of these layers are not represented in these structural models. The goal of this paper is to give few possibilities to overcome these difficulties.

  12. Ultimately Thin Metasurface Wave Plates

    OpenAIRE

    Keene, David; LePain, Matthew; Durach, Maxim

    2015-01-01

    Optical properties of a metasurface which can be considered a monolayer of two classical uniaxial metamaterials, parallel-plate and nanorod arrays, are investigated. It is shown that such metasurface acts as an ultimately thin sub-50 nm wave plate. This is achieved via an interplay of epsilon-near-zero and epsilon-near-pole behavior along different axes in the plane of the metasurface allowing for extremely rapid phase difference accumulation in very thin metasurface layers. These effects are...

  13. Modified tubularized incised plate urethroplasty

    OpenAIRE

    Shivaji Mane; Jamir Arlikar; Nitin Dhende

    2013-01-01

    Aim: To share our experience of doing tubularized incised plate urethroplasty with modifications. Materials and Methods: This is a single surgeon personal series from 2004 to 2009. One hundred patients of distal hypospadias were subjected for Snodgrass urethroplasty with preputioplasty. The age range was 1 to 5 year with mean age of 2.7 years. Selection criteria were good urethral plate, without chordee and torsion needing complete degloving. Main technical modification from original Snodgras...

  14. Horizontally oriented plates in clouds

    CERN Document Server

    Bréon, François-Marie

    2011-01-01

    Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as "subsun". This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud top layer and their characteristic tilt angle to the horizontal. We make use of spaceborne measurements from the POLDER instrument to provide a statistical analysis of these parameters. More than half of the clouds show a detectable maximum reflectance in the glint direction, although this maximum may be rather faint. The typical effective fraction (area weighted) of oriented plates in clouds lies between 10-3 and 10-2. For those oriented plates, the characteristic tilt angle is less than 1 degree in most cases. These low fractions imply that the impact of oriented plates on the cloud albedo is insignificant. The largest proportion of clouds with horizontally oriented plates is found in the range 500-700 hPa, in agreement with typical in situ observation of p...

  15. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  16. Simple method to demonstrate radiation-inducible radiation resistance in microbial cells.

    OpenAIRE

    Tan, S. T.; Maxcy, R. B.

    1986-01-01

    A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a "fixed" ...

  17. Performance evaluation and characterization of metallic bipolar plates in a proton exchange membrane (PEM) fuel cell

    Science.gov (United States)

    Hung, Yue

    Bipolar plate and membrane electrode assembly (MEA) are the two most repeated components of a proton exchange membrane (PEM) fuel cell stack. Bipolar plates comprise more than 60% of the weight and account for 30% of the total cost of a fuel cell stack. The bipolar plates perform as current conductors between cells, provide conduits for reactant gases, facilitate water and thermal management through the cell, and constitute the backbone of a power stack. In addition, bipolar plates must have excellent corrosion resistance to withstand the highly corrosive environment inside the fuel cell, and they must maintain low interfacial contact resistance throughout the operation to achieve optimum power density output. Currently, commercial bipolar plates are made of graphite composites because of their relatively low interfacial contact resistance (ICR) and high corrosion resistance. However, graphite composite's manufacturability, permeability, and durability for shock and vibration are unfavorable in comparison to metals. Therefore, metals have been considered as a replacement material for graphite composite bipolar plates. Since bipolar plates must possess the combined advantages of both metals and graphite composites in the fuel cell technology, various methods and techniques are being developed to combat metallic corrosion and eliminate the passive layer formed on the metal surface that causes unacceptable power reduction and possible fouling of the catalyst and the electrolyte. The main objective of this study was to explore the possibility of producing efficient, cost-effective and durable metallic bipolar plates that were capable of functioning in the highly corrosive fuel cell environment. Bulk materials such as Poco graphite, graphite composite, SS310, SS316, incoloy 800, titanium carbide and zirconium carbide were investigated as potential bipolar plate materials. In this work, different alloys and compositions of chromium carbide coatings on aluminum and SS316

  18. Effect of copper-plating on hydrogen storage performance of a La-Ni-Al metal hydride

    Energy Technology Data Exchange (ETDEWEB)

    Bin Liao [Academy of Sciences, Shenyang (China). Inst. of Metal Research]|[Inst. of Structural Michanics, Chinese Academy of Engineering Physics, Mianyang (China); Manqi Lu; Ke Yang [Academy of Sciences, Shenyang (China). Inst. of Metal Research; Dehui Zhou; Ying Fan; Xun Yang; Yun Tan [Inst. of Structural Michanics, Chinese Academy of Engineering Physics, Mianyang (China)

    2001-07-01

    Metal hydride compacts were prepared by compressing LaNi{sub 4.75}Al{sub 0.25} alloy powders with copper chemical plating or copper acidic electroless plating. The compacts show a remarkable improvement on the hydrogen desorption rate, compared to the powders before plating. The thermal diffusion coefficient of the metal hydride compacts are 10-15 times higher than that of the LaNi{sub 5} bulk and the compacts show no obvious breaks after 10 absorption-desorption cycles. Copper plating has no effect on the thermodynamics as well as the phase structure of the matrix alloy. The plating copper layer prepared by acidic electroless plating has poor plasticity and poor pulverization-resistance because it is a mixture of copper and the matrix. The hydrogen storage capacity of matrix is much reduced after acidic electroless plating because the matrix elements are replaced by the copper and then dissolved during plating. While the copper layer prepared by chemical-plating shows good pulverization-resistance, the plated powders have less loss of hydrogen storage capacity than that of acidic electroless plating. (orig.)

  19. Calculating crawler track plates for surface mining equipment - part 2

    Energy Technology Data Exchange (ETDEWEB)

    Schoenemann, F.

    1988-02-01

    Demonstrates calculation procedures for static stress, steel fatigue strength and buckling resistance of crawler track links on heavy surface mining equipment according to the VBK 0052 instruction of the TAKRAF manufacturer in the GDR. Maximum permissible stresses (139 to 355 N/mm/sup 2/) for 3 locations at the link's cross section are listed. Static stress calculations concern the welded joints of the link to the sheet metal body and the buckling of the link's bottom plate. A formula for bottom plate deformation forces is provided. Stresses are different for driving on solid overburden or on dumped spoil surfaces. Values derived from fatigue experiments are provided for permanent fatigue strength of welded seams of the link. Buckling resistance has to be determined only for load conditions of partial link contact to the ground surface.

  20. Comparison of abrasion resistance of selected constructional materials

    Directory of Open Access Journals (Sweden)

    M. Adamiak

    2009-12-01

    Full Text Available Purpose: The aim of this work was to define and compare abrasion resistance of selected constructional materials widely used in the industry. Chromium cast iron wear resistant plates were compared with typically used wear resistant plates made from Hardox 400 steel and two different, wear resistant, materials cladded by welding technologies.Design/methodology/approach: The tests of abrasive wear were conducted in accordance to procedure “A” of standard ASTM G 65 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus.Findings: Abrasion resistance tests shows that the best properties among investigated samples has chromium cast iron plate. Abrasion wear resistance of this plate is two times higher than wear resistance of layer made by welding technologies and nine times higher than typical Hardox 400 steel plate.Practical implications: Application, of abrasion resistant materials, results in significant material and economy savings, due to wear and costs reduction (decreasing stop times needed to change worn parts for a new one.Originality/value: Wear plates are modern solution in regeneration of worn machines parts and also for producing a new parts which connect high wear and abrasion resistance with costs reduction.

  1. The Subduction Dichotomy of Strong Plates and Weak Slabs

    OpenAIRE

    Petersen, Robert I.; Stegman, Dave R.; Tackley, Paul J.

    2016-01-01

    A key element of plate tectonics on Earth is that the lithosphere is subducting into the mantle. Subduction results from forces that bend and pull the lithosphere into the interior of the Earth. Once subducted, lithospheric slabs are further modified by dynamic forces in the mantle and their sinking is inhibited by the increase in viscosity of the lower mantle. These forces are resisted by the material strength of the lithosphere. Using geodynamic models we investigate several subductio...

  2. Dorsal Buttress Plate Fixation of Ulnar Carpometacarpal Joint Fracture Dislocations.

    Science.gov (United States)

    Tan, En Si; Chao, Tay Shian

    2016-06-01

    We propose a method for open reduction and internal fixation of early and unstable ulnar (fourth and/or fifth) carpometacarpal joint (CMCJ) fracture subluxations or dislocations using a dorsal buttress plate. In ulnar CMCJ fracture dislocations, the metacarpal has a tendency to displace dorsally and proximally when there is an axial load. Using the dorsal buttress plate method of fixation, a plate is fixed proximally to the hamate, aligned parallel and dorsal to the metacarpal to act as a buttress, to resist this movement. To preserve the fourth and the fifth CMCJ mobility, the distal end of the plate is not fixed to the metacarpal base. We illustrate the use of this technique on 4 patients who had different patterns of injury at the ulnar CMCJ. All patients regained excellent range of motion and function. None of the patients had redisplacement or nonunion of fracture. The dorsal buttress plate is a viable option for fixation of early and unstable ulnar CMCJ fracture subluxations or dislocations. PMID:27077465

  3. CHARACTERISTICS OF LOW TEMPERATURE ION PLATING TiN COATINGS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The TiN coatings were deposited onto the low carbon steel substrates with different temperatures (150,250,350 and 450 ℃), using hollow cathode discharge (HCD) ion plating method. The measurements of the microhardness and wear resistance of the coatings show that the hardness value slowly increases and the wear resistance remains almost unchanged with increasing the substrate temperature from 150 ℃ to 450 ℃. The reason for effect of the substrate temperature on the properties and morphologies of the coatings was investigated by means of X-ray diffraction and scanning electron microscope (SEM).

  4. Surface modified stainless steels for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Wang, Heli [Littleton, CO; Turner, John A [Littleton, CO

    2007-07-24

    A nitridation treated stainless steel article (such as a bipolar plate for a proton exchange membrane fuel cell) having lower interfacial contact electrical resistance and better corrosion resistance than an untreated stainless steel article is disclosed. The treated stainless steel article has a surface layer including nitrogen-modified chromium-base oxide and precipitates of chromium nitride formed during nitridation wherein oxygen is present in the surface layer at a greater concentration than nitrogen. The surface layer may further include precipitates of titanium nitride and/or aluminum oxide. The surface layer in the treated article is chemically heterogeneous surface rather than a uniform or semi-uniform surface layer exclusively rich in chromium, titanium or aluminum. The precipitates of titanium nitride and/or aluminum oxide are formed by the nitriding treatment wherein titanium and/or aluminum in the stainless steel are segregated to the surface layer in forms that exhibit a low contact resistance and good corrosion resistance.

  5. Analytical solution for multilayer plates using general layerwise plate theory

    Directory of Open Access Journals (Sweden)

    Vuksanović Đorđe M.

    2005-01-01

    Full Text Available This paper deals with closed-form solution for static analysis of simply supported composite plate, based on generalized laminate plate theory (GLPT. The mathematical model assumes piece-wise linear variation of in-plane displacement components and a constant transverse displacement through the thickness. It also include discrete transverse shear effect into the assumed displacement field, thus providing accurate prediction of transverse shear stresses. Namely, transverse stresses satisfy Hook's law, 3D equilibrium equations and traction free boundary conditions. With assumed displacement field, linear strain-displacement relation, and constitutive equations of the lamina, equilibrium equations are derived using principle of virtual displacements. Navier-type closed form solution of GLPT, is derived for simply supported plate, made of orthotropic laminae, loaded by harmonic and uniform distribution of transverse pressure. Results are compared with 3D elasticity solutions and excellent agreement is found.

  6. Electroless silver plating on tetraethoxy silane-bridged fiber glass

    International Nuclear Information System (INIS)

    Tetraethoxy silane was used to functionalize the surface of fiber glass (FG) for adsorption with the electroless plated silver shell. The performance of electroless silver plated FG with tetraethoxy silane modification was compared to that of unmodified FG in terms of mechanical and electrical properties. The silane bridge provided more stability for binding with different concentrations of electroless plating silver ions. The characterization was investigated by using field emission scanning electron microscope (FESEM), X-ray diffraction patterns (XRD), energy-dispersion X-ray (EDX), metal microscope (MM) and electric resistance. The Ag coating on TEOS modified FG was more durable than that of unmodified FG in the ball milling test, as confirmed by the data of electric resistance and residue weight. The optimized conditions for producing the Ag coating FG were also investigated. The Ag-Si-FG-3-c product in this study has the lowest electrical resistance of 1.56 × 103 Ω/cm2 and good mechanical stability as exhibited in ball milling tests.

  7. Electroless silver plating on tetraethoxy silane-bridged fiber glass

    Energy Technology Data Exchange (ETDEWEB)

    Lien, Wan-Fu [Department of Cultural Heritage Conservation, National Yunlin University of Science and Technology, 123, Section 3, University Road, Touliu, Yunlin 640, Taiwan (China); Huang, Po-Chen [Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123, Section 3, University Road, Touliu, Yunlin 640, Taiwan (China); Tseng, Shi-Chang [Department of Mechanical Engineering, National Yunlin University of Science and Technology, 123, Section 3, University Road, Touliu, Yunlin 640, Taiwan (China); Cheng, Chia-Hsiang; Lai, Shih-Ming [Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123, Section 3, University Road, Touliu, Yunlin 640, Taiwan (China); Liaw, Wen-Chang, E-mail: liawwc@hotmail.com [Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123, Section 3, University Road, Touliu, Yunlin 640, Taiwan (China)

    2012-01-15

    Tetraethoxy silane was used to functionalize the surface of fiber glass (FG) for adsorption with the electroless plated silver shell. The performance of electroless silver plated FG with tetraethoxy silane modification was compared to that of unmodified FG in terms of mechanical and electrical properties. The silane bridge provided more stability for binding with different concentrations of electroless plating silver ions. The characterization was investigated by using field emission scanning electron microscope (FESEM), X-ray diffraction patterns (XRD), energy-dispersion X-ray (EDX), metal microscope (MM) and electric resistance. The Ag coating on TEOS modified FG was more durable than that of unmodified FG in the ball milling test, as confirmed by the data of electric resistance and residue weight. The optimized conditions for producing the Ag coating FG were also investigated. The Ag-Si-FG-3-c product in this study has the lowest electrical resistance of 1.56 Multiplication-Sign 10{sup 3} {Omega}/cm{sup 2} and good mechanical stability as exhibited in ball milling tests.

  8. Electroless silver plating on tetraethoxy silane-bridged fiber glass

    Science.gov (United States)

    Lien, Wan-Fu; Huang, Po-Chen; Tseng, Shi-Chang; Cheng, Chia-Hsiang; Lai, Shih-Ming; Liaw, Wen-Chang

    2012-01-01

    Tetraethoxy silane was used to functionalize the surface of fiber glass (FG) for adsorption with the electroless plated silver shell. The performance of electroless silver plated FG with tetraethoxy silane modification was compared to that of unmodified FG in terms of mechanical and electrical properties. The silane bridge provided more stability for binding with different concentrations of electroless plating silver ions. The characterization was investigated by using field emission scanning electron microscope (FESEM), X-ray diffraction patterns (XRD), energy-dispersion X-ray (EDX), metal microscope (MM) and electric resistance. The Ag coating on TEOS modified FG was more durable than that of unmodified FG in the ball milling test, as confirmed by the data of electric resistance and residue weight. The optimized conditions for producing the Ag coating FG were also investigated. The Ag-Si-FG-3-c product in this study has the lowest electrical resistance of 1.56 × 103 Ω/cm2 and good mechanical stability as exhibited in ball milling tests.

  9. Modeling RERTR experimental fuel plates using the PLATE code

    International Nuclear Information System (INIS)

    Modeling results using the PLATE dispersion fuel performance code are presented for the U-Mo/Al experimental fuel plates from the RERTR-1, -2, -3 and -5 irradiation tests. Agreement of the calculations with experimental data obtained in post-irradiation examinations of these fuels, where available, is shown to be good. Use of the code to perform a series of parametric evaluations highlights the sensitivity of U-Mo dispersion fuel performance to fabrication variables, especially fuel particle shape and size distributions. (author)

  10. Beyond plate tectonics - Looking at plate deformation with space geodesy

    Science.gov (United States)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  11. Plating on some difficult-to-plate metals and alloys

    International Nuclear Information System (INIS)

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests

  12. RELATION OF PLATE STRAIN AND DISTANCE BETWEEN PLATE AND BONE

    OpenAIRE

    Boonthum Wongchai

    2013-01-01

    The Limited Contact Dynamics Compression Plate (LC-DCP) is normally used in bone fractured with the locking screws. The released distance between the LC-DCP and the bone could bring about the convenience of periosteal blood transportation. However the exceeding distance may cause the plate strain reach yield point and make the LC-DCP deform into plastic zone. This research proposes a study of the effect of the distance between the LC-DCP and the bone on the strain in the LC-DCP. The strains a...

  13. Plating on some difficult-to-plate metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dini, J.W.; Johnson, H.R.

    1980-02-01

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests.

  14. Marching of Freely Falling Plates

    CERN Document Server

    Wan, Hui; Gaston, Zachary; Liang, Zongxian

    2011-01-01

    "Marching of freely falling plates" is a fluid dynamics video for the Gallery of Fluid Motion submitted to APS-DFD 2011 at Baltimore Maryland. The problem of a freely falling plate is of interest in both fluid mechanics and nonlinear dynamics. The trajectory of the plate can be regular (Willmarth et al., 1964) or chaotic (Aref and Jones, 1993). As long as Reynolds number is high enough, regular flutter and tumble motion can be obtained for plates with small and large Froude numbers respectively. Belmonte et al. (1998) conducted experimental study on thin flat strips falling in a vertical cell. They categorized the Froude number at which the transition from fluttering to tumbling occurs. Andersen et al. (2005) analyzed the transitions between fluttering and tumbling using vorticity-stream function formulation and ODE dynamic equations based on quasi-steady models. They also found that the fluid circulation is mainly generated by the plate rotation and its angular velocity. However, the correlation among the pl...

  15. Breeding High-yielding Strains of Oxytetracycline with UV Mutagenesis, Oxytetracycline Resistance Screening and Gradient Plate Method%利用梯度平板法结合紫外诱变、抗性筛选选育土霉素高产菌株

    Institute of Scientific and Technical Information of China (English)

    王小娟; 张萍; 逄春梅; 石彦鹏

    2014-01-01

    UV mutagenesis,antibiotics resistance screening and gradient plate method were used to screen high-yielding strains of oxytetracycline directionly by using Streptomyces rimosus TMSⅠ12-66 as the original strain. The results showed that the dose of UV irradiation was determined 90 s in term of death rate. Using isolation medium with lithium chloride on the upper layer and tetracycline on the bottom layer, a high - yield oxytetracycline-producing strain named TMSⅠ12 - 66 was obtained, whose shaking production reached 22985 mg/mL, increased by 22.36 % than the original strain, its character was stable after five generations.%以龟裂链霉素TMSⅠ12-66为出发菌株,通过紫外-氯化锂诱变处理,并结合梯度平板法、氯化锂和四环素复合抗性平板上筛选土霉素高产菌株。通过对致死率的考察,确定了紫外的最佳诱变剂量为90 s。在分离培养基上层加入氯化锂和底层加入四环素进行正突变株的定向筛选。经过选育得到一株土霉素的高产菌株TMSⅠ14-180,摇瓶发酵验证效价达22985 mg/mL,较出发菌株提高22.36%,经传代试验考察,该菌株遗传性状稳定。

  16. XIth Workshop on Resistive Plate Chambers and Related Detectors

    Science.gov (United States)

    RPC2012 continues the tradition of regular scientific meetings, first started in 1991 at Lecce, with following editions in Roma, Pavia, Napoli, Bari, Coimbra, Clermont-Ferrand, Seoul, Mumbai, Darmstadt. The RPC detection technique has found large application in LHC detectors and in astroparticle physics experiments. The workshop focused on performance of large RPC systems, ageing and detector materials studies, electronics for RPCs, physics of basic processes in the gas, timing applications, new ideas for RPC detectors.

  17. Description and simulation of physics of Resistive Plate Chambers

    CERN Document Server

    Français, Vincent

    2016-01-01

    Monte-Carlo simulation of physical processes is an important tool for detector development as it allows to predict signal pulse amplitude and timing, time resolution, efficiency ... Yet despite the fact they are very common, full simulations for RPC-like detector are not widespread and often incomplete. They are often based on mathematical distributions that are not suited for this particular modelisation and over-simplify or neglect some important physical processes. We describe the main physical processes occurring inside a RPC when a charged particle goes through (ionisation, electron drift and multiplication, signal induction ...) through the Riegler-Lippmann-Veenhof model together with a still-in-development simulation. This is a full, fast and multi-threaded Monte-Carlo modelisation of the main physical processes using existing and well tested libraries and framework (such as the Garfield++ framework and the GNU Scientific Library). It is developed in the hope to be a basic ground for future RPC simulat...

  18. Space charge effects and induced signals in resistive plate chambers

    CERN Document Server

    Lippmann, Christian; Schnizer, Bernhard

    2003-01-01

    Using special integral representations of the solution for the static electric field of a point charge in a three layer geometry with different permittivities, we calculate the effect of the space charge on the avalanche in the gas gap of an RPC. A detailed Monte Carlo simulation was developed which allows calculation of the actual charge spectrum. Results of this simulation are presented, using the example of a trigger-RPC with 2 mm gas gap, similar to the ones used by ATLAS (ATLAS TDR 10, CERN-LHCC-97-22), and a timing RPC with 300 mum gas gap (Nucl. Instr. and Meth. A 449 (2000) 295). Finally, we also present analytic solutions for the weighting field of an RPC readout strip, which allow to calculate the directly induced crosstalk and induced signals.

  19. Dynamics of diffuse oceanic plate boundaries: insensitivity to rheology

    Science.gov (United States)

    Zatman, Stephen; Gordon, Richard G.; Mutnuri, Kartik

    2005-07-01

    Diffuse plate boundaries, which are zones of deformation hundreds to thousands of kilometres wide, occur in both continental and oceanic lithosphere. Here, we build on our prior work in which we described analytic approximations to simple dynamical models that assume that the vertically averaged viscous force resisting deformation in diffuse oceanic plate boundaries (DOPBs) is described by either a linear Newtonian viscous rheology or a yield-stress (high-exponent power-law) rheology. An important observation is that the poles of relative rotation of adjacent component plates tend to lie in the diffuse plate boundary that separates them. A key cause of this tendency is that a faster spin is needed to balance a component of torque through the middle of a diffuse plate boundary than to balance an equal component of torque lying 90° from the middle of the diffuse boundary. The strength of that tendency depends on rheology, however, with the tendency being stronger for a yield-stress rheology than for a Newtonian viscous rheology. For the special case of the pole of rotation lying outside of and along the strike of the boundary, these large differences can be simply explained in terms of the distribution of boundary-perpendicular normal forces acting across the boundary. In the Newtonian case, the distribution of forces has an along-strike gradient that can balance a component of torque about the middle of the boundary, while in the yield-stress case, the distribution of forces has zero along-strike gradient and cannot balance a component of torque about the middle of the diffuse plate boundary. To expand our analysis to intermediate power laws of geophysical interest (i.e. power-law exponents of 3 to 30), as well as to investigate more thoroughly the behaviour for a high-exponent power law, we numerically integrate the force distribution to obtain the torques. Results for intermediate power laws resemble the yield-stress rheology much more than they resemble the

  20. Ultimately Thin Metasurface Wave Plates

    CERN Document Server

    Keene, David; Durach, Maxim

    2015-01-01

    Optical properties of a metasurface which can be considered a monolayer of two classical uniaxial metamaterials, parallel-plate and nanorod arrays, are investigated. It is shown that such metasurface acts as an ultimately thin sub-50 nm wave plate. This is achieved via an interplay of epsilon-near-zero and epsilon-near-pole behavior along different axes in the plane of the metasurface allowing for extremely rapid phase difference accumulation in very thin metasurface layers. These effects are shown to not be disrupted by non-locality and can be applied to the design of ultrathin wave plates, Pancharatnam-Berry phase optical elements and plasmon-carrying optical torque wrench devices.

  1. Dual polarization flat plate antenna

    Science.gov (United States)

    Kelly, Kenneth C.

    Rectangular waveguides with radiating slots are used in groups to form planar array microwave antennas with large apertures and small depth. Such flat plate antennas are widely used on spacecraft and aircraft. Typically, flat plate antennas provide fixed linear polarization. The present paper describes a new flat plate antenna which produces two coincident beams that are distinguished by their orthogonal linear polarizations. The antenna has two ports, one for each of the coicident beams. Completely external to the antenna, connecting a simple network to those terminal ports enables the antenna to provide right circular polarization from one port and left from the other. A different external network enables the antenna to have arbitrarily adjustable polarizations.

  2. Positive selection for loss of tetracycline resistance.

    OpenAIRE

    Bochner, B R; Huang, H. C.; Schieven, G L; Ames, B N

    1980-01-01

    A simple technique has been devised that allows direct plate selection of tetracycline-sensitive clones from a predominantly tetracycline-resistant population. The technique is especially useful in genetic methodologies based on the use of tetracycline resistance transposons, such as Tn10. Potential uses of the method include selection of deletion mutants, fine-structure mapping, generalized mapping, construction of multiply marked strains, elimination of tetracycline resistance transposons a...

  3. Semiclassical theory of plate vibrations

    International Nuclear Information System (INIS)

    The bi-harmonic equation of flexural vibrations of elastic plates is studied by a semiclassical method which can easily be generalized for other models of wave propagation. The surface and perimeter terms of the asymptotic number of levels are derived exactly. The next constant term is also derived. A semiclassical approximation of the quantization condition is obtained. A Berry-Tabor formula and a Gutzwiller trace formula are deduced for the integrable and chaotic cases respectively. From 600 eigenvalues of a clamped stadium plate obtained by a specially developed numerical algorithm, the trace formula is assessed, looking at its Fourier transform compared with the membrane case. (author)

  4. Highly conductive thermoplastic composites for rapid production of fuel cell bipolar plates

    Science.gov (United States)

    Huang, Jianhua [Blacksburg, VA; Baird, Donald G [Blacksburg, VA; McGrath, James E [Blacksburg, VA

    2008-04-29

    A low cost method of fabricating bipolar plates for use in fuel cells utilizes a wet lay process for combining graphite particles, thermoplastic fibers, and reinforcing fibers to produce a plurality of formable sheets. The formable sheets are then molded into a bipolar plates with features impressed therein via the molding process. The bipolar plates formed by the process have conductivity in excess of 150 S/cm and have sufficient mechanical strength to be used in fuel cells. The bipolar plates can be formed as a skin/core laminate where a second polymer material is used on the skin surface which provides for enhanced conductivity, chemical resistance, and resistance to gas permeation.

  5. Highly adhesive metal plating on Zylon ® fiber via iodine pretreatment

    Science.gov (United States)

    Fatema, Ummul Khair; Gotoh, Yasuo

    2011-11-01

    Highly adhesive metal plating was performed on poly(p-phenylene-2,6-benzobisoxazole) fiber named Zylon® via iodine pretreatment followed by electroless plating. First, iodine components were selectively doped into the inner part of the fiber near the surface through iodine vapor exposure. The doped iodine was converted to palladium iodide particles by treating with palladium chloride solution. After the reduction of the iodide to metal palladium particles, electroless copper plating was conducted on the fiber. A uniform copper layer was deposited on the fiber surface and exhibited high durability in durability tests such as ultrasonic exposure, tape peeling-off, and corrosion in NaCl solution. This durability was attributed to the palladium particles formed at the fiber surface that served as an anchor for the plated layer as well as an electroless plating catalyst. The plated fibers also possessed electrical conductivity. Although the tensile strength of the Zylon® fiber decreased from 5.8 to 4.9 GPa after undergoing the pretreatment and plating processes, the light shielding effect improved the light resistance of the plated fibers in terms of tensile properties. After 18 days of xenon lamp exposure, the plated fibers retained 74% of its initial strength, whereas that of untreated fibers decreased to 43%.

  6. Modeling pore corrosion in normally open gold- plated copper connectors.

    Energy Technology Data Exchange (ETDEWEB)

    Battaile, Corbett Chandler; Moffat, Harry K.; Sun, Amy Cha-Tien; Enos, David George; Serna, Lysle M.; Sorensen, Neil Robert

    2008-09-01

    The goal of this study is to model the electrical response of gold plated copper electrical contacts exposed to a mixed flowing gas stream consisting of air containing 10 ppb H{sub 2}S at 30 C and a relative humidity of 70%. This environment accelerates the attack normally observed in a light industrial environment (essentially a simplified version of the Battelle Class 2 environment). Corrosion rates were quantified by measuring the corrosion site density, size distribution, and the macroscopic electrical resistance of the aged surface as a function of exposure time. A pore corrosion numerical model was used to predict both the growth of copper sulfide corrosion product which blooms through defects in the gold layer and the resulting electrical contact resistance of the aged surface. Assumptions about the distribution of defects in the noble metal plating and the mechanism for how corrosion blooms affect electrical contact resistance were needed to complete the numerical model. Comparisons are made to the experimentally observed number density of corrosion sites, the size distribution of corrosion product blooms, and the cumulative probability distribution of the electrical contact resistance. Experimentally, the bloom site density increases as a function of time, whereas the bloom size distribution remains relatively independent of time. These two effects are included in the numerical model by adding a corrosion initiation probability proportional to the surface area along with a probability for bloom-growth extinction proportional to the corrosion product bloom volume. The cumulative probability distribution of electrical resistance becomes skewed as exposure time increases. While the electrical contact resistance increases as a function of time for a fraction of the bloom population, the median value remains relatively unchanged. In order to model this behavior, the resistance calculated for large blooms has been weighted more heavily.

  7. Strengthening of steel–concrete composite girders using carbon fibre reinforced polymer (CFRP) plates

    Indian Academy of Sciences (India)

    S M Mosavi; A Sadeghi Nik

    2015-02-01

    Applying composites in order to strengthen and renew the infrastructures has globally been accepted. Traditional methods to strengthen the out-of-standard structures are costly, time consuming and requires a lot of labour. Today, new techniques are hired using light and strong substances which also resist against corrosion, known as Carbon Fibre Reinforced Polymer (CFRP) plates. Regarding the high tensile strength and proper module of elasticity, CFRP plates are considered as a suitable alternative to strengthen girders. The behaviour of steel–concrete composite girders being statically loaded and strengthened by CFRP plates in this study. The CFRP plates used in this study have been stuck, with epoxy adhesive, under the tensile sections of three steel girders. The results accompanied with analytical study of moment–curvature and numerical analysis done with ANSYS, show that CFRP plates with epoxy adhesive increases the ultimate loading capacity of steel–concrete composite girder. Plastic stiffness of the girders was also increased.

  8. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    International Nuclear Information System (INIS)

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection

  9. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, O.H.W., E-mail: ossy@ssl.berkeley.edu [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); McPhate, J.B.; Tremsin, A.S.; Vallerga, J.V.; Ertley, C.D.; Richner, N.J.; Gerard, T.M. [Experimental Astrophysics Group, Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720 (United States); Frisch, H.J. [University of Chicago, 5640 S. Ellis Ave., Chicago, Il 60637 (United States); Elam, J.W.; Mane, A.U.; Wagner, R.G. [Argonne National Laboratory, 9700 S. Cass Ave. Lemont, Il 60439 (United States); Minot, M.J.; O' Mahony, A.; Craven, C.A. [Incom Inc., 294 Southbridge Road, Charlton, MA, 01507 (United States)

    2015-07-01

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  10. Drug Resistance

    Science.gov (United States)

    HIV Treatment Drug Resistance (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points As HIV multiplies in the ... the risk of drug resistance. What is HIV drug resistance? Once a person becomes infected with HIV, ...

  11. Elastic stability of thick auxetic plates

    International Nuclear Information System (INIS)

    Auxetic materials and structures exhibit a negative Poisson’s ratio while thick plates encounter shear deformation, which is not accounted for in classical plate theory. This paper investigates the effect of a negative Poisson’s ratio on thick plates that are subjected to buckling loads, taking into consideration the shear deformation using Mindlin plate theory. Using a highly accurate shear correction factor that allows for the effect of Poisson’s ratio, the elastic stability of circular and square plates are evaluated in terms of dimensionless parameters, namely the Mindlin-to-Kirchhoff critical buckling load ratio and Mindlin critical buckling load factors. Results for thick square plates reveal that both parameters increase as the Poisson’s ratio becomes more negative. In the case of thick circular plates, the Mindlin-to-Kirchhoff critical buckling load ratios and the Mindlin critical buckling load factors increase and decrease, respectively, as the Poisson’s ratio becomes more negative. The results obtained herein show that thick auxetic plates behave as thin conventional plates, and therefore suggest that the classical plate theory can be used to evaluate the elastic stability of thick plates if the Poisson’s ratio of the plate material is sufficiently negative. The results also suggest that materials with highly negative Poisson’s ratios are recommended for square plates, but not circular plates, that are subjected to buckling loads. (paper)

  12. Crack propagation in prestressed plates

    Energy Technology Data Exchange (ETDEWEB)

    Farshad, M.; Flueler, P. [EMPA, Duebendorf (Switzerland)

    1995-12-31

    A second-order theory of initially stressed plates in the plane stress mode was used to find the dynamic stress field in the vicinity of a crack tip. Rapid crack propagation (RCP) behaviour associated with stresses caused by internal pressure and temperature was examined. The flat plate was placed under thermal conditions and was prestressed in such a way as to simulate hoop stress that may be expected in a pipe made of the same material. The presence of the tensile prestress in the thin plate raised the levels of the principal stress values and affected the direction at which the maxima of principal stress occurred. Second-order effects played an important role in the vicinity of the crack tip. Increased crack speed caused increased stress levels. There existed a limiting value at which the stresses at the crack tip became unbounded. The limiting value was affected by prestressing. The concept of simulating RCP testing of polymer pipes by a test on a conditioned plate of the same material, prestressed to simulate hoop stress caused by internal pressure, was judged to be reasonable. 6 refs. 5 figs.

  13. MyPlate Daily Checklist

    Science.gov (United States)

    ... Eat Fruits Food Gallery Vegetables All About the Vegetable Group Nutrients and Health Benefits Tips to Help You Eat Vegetables Beans ... Updated: Jun 7, 2016 RESOURCES FOR NUTRITION AND HEALTH MYPLATE What Is MyPlate? Fruits Vegetables Grains Protein Foods Dairy Oils ONLINE TOOLS SuperTracker ...

  14. Scale-up of Carbon/Carbon Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    David P. Haack

    2009-04-08

    This project was focused upon developing a unique material technology for use in PEM fuel cell bipolar plates. The carbon/carbon composite material developed in this program is uniquely suited for use in fuel cell systems, as it is lightweight, highly conductive and corrosion resistant. The project further focused upon developing the manufacturing methodology to cost-effectively produce this material for use in commercial fuel cell systems. United Technology Fuel Cells Corp., a leading fuel cell developer was a subcontractor to the project was interested in the performance and low-cost potential of the material. The accomplishments of the program included the development and testing of a low-cost, fully molded, net-shape carbon-carbon bipolar plate. The process to cost-effectively manufacture these carbon-carbon bipolar plates was focused on extensively in this program. Key areas for cost-reduction that received attention in this program was net-shape molding of the detailed flow structures according to end-user design. Correlations between feature detail and process parameters were formed so that mold tooling could be accurately designed to meet a variety of flow field dimensions. A cost model was developed that predicted the cost of manufacture for the product in near-term volumes and long-term volumes (10+ million units per year). Because the roduct uses lowcost raw materials in quantities that are less than competitive tech, it was found that the cost of the product in high volume can be less than with other plate echnologies, and can meet the DOE goal of $4/kW for transportation applications. The excellent performance of the all-carbon plate in net shape was verified in fuel cell testing. Performance equivalent to much higher cost, fully machined graphite plates was found.

  15. Performance of electrocatalytic gold coating on bipolar plates for SO2 depolarized electrolyser

    Science.gov (United States)

    Santasalo-Aarnio, A.; Lokkiluoto, A.; Virtanen, J.; Gasik, M. M.

    2016-02-01

    One of the largest obstacles for SO2 depolarized electrolyser (SDE) commercialization is the material stability in rough operating conditions. In this work stainless steel bipolar plates have been coated with thin Au layer having bifunctional role: providing electrocatalytic surface for both electrode reactions and simultaneously improves the stainless steel support corrosion tolerance at the potential window of SDE. The stability and performance of the coated bipolar plates were tested in a bench-scale electrolyser set-up and the results indicate that these plates can be utilized as economic catalyst for SDE, moreover, they show corrosion resistance in SDE operation.

  16. Quantifying antimicrobial resistance at veal calf farms.

    Directory of Open Access Journals (Sweden)

    Angela B Bosman

    Full Text Available This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.5 mg/L cefotaxime, 0.125 mg/L ciprofloxacin and 8/152 mg/L trimethoprim/sulfamethoxazole (tmp/s by replica plating. From each faecal sample another 10 selected E. coli isolates were tested for their resistance by broth microdilution as a reference. Logistic regression analysis was performed to compare the odds of testing an isolate resistant between both test methods (replica plating vs. broth microdilution and to evaluate the effect of pooling faecal samples. Bootstrap analysis was used to investigate the precision of the estimated prevalence of resistance to each antimicrobial obtained by several simulated sampling strategies. Replica plating showed similar odds of E. coli isolates tested resistant compared to broth microdilution, except for ciprofloxacin (OR 0.29, p ≤ 0.05. Pooled samples showed in general lower odds of an isolate being resistant compared to individual samples, although these differences were not significant. Bootstrap analysis showed that within each antimicrobial the various compositions of a pooled sample provided consistent estimates for the mean proportion of resistant isolates. Sampling strategies should be based on the variation in resistance among isolates within faecal samples and between faecal samples, which may vary by antimicrobial. In our study, the optimal sampling strategy from the perspective of precision of the estimated levels of resistance and practicality consists of a pooled faecal sample from 20 individual animals, of which

  17. Investigation of CaCO3 fouling in plate heat exchangers

    Science.gov (United States)

    Li, Wei; Zhou, Kan; Manglik, Raj M.; Li, Guan-Qiu; Bergles, Arthur E.

    2016-01-01

    An experimental investigation, coupled with theoretical modeling of CaCO3 fouling in plate-and-frame type heat exchangers (PHEs) have been conducted. Four different plates, made of SS-304, are used in two different surface patterns (chevron and zig-zag) of varying corrugation severity (waviness depth and pitch) and area enhancement. They were further characterized in clean, non-fouled convection by their measured heat transfer coefficients and friction factors in the Reynolds number range of 600-6000. The flow-fouling experiments delineate the effects of temperature and plate-surface geometry on growth rates and stabilization of fouling resistance, along with the anti-fouling behavior of plates coated with a hydrophobic PTFE (Teflon) film. Moreover, the microscopic structure of fouling deposits is mapped in a scanning-electron microscope. Corrugated plates with the largest height-to-pitch ratio and hydraulic diameter are found to have the lowest fouling growth rate and resistance; Teflon-film coating of plate surface is also found to mitigate fouling relative to the performance of bare stainless steel plates. Finally, a semi-empirical fouling model, based on the Prandtl-Taylor analogy, has been devised to describe the experimental data and provide a predictive tool.

  18. Structural Analysis of Plate Based Tensegrity Structures

    DEFF Research Database (Denmark)

    Hald, Frederik; Kirkegaard, Poul Henning; Damkilde, Lars

    2013-01-01

    Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method for...... determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed....

  19. Avionics Box Cold Plate Damage Prevention

    Science.gov (United States)

    Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

    2012-01-01

    Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

  20. Low thermal resistance power module assembly

    Science.gov (United States)

    Hassani, Vahab; Vlahinos, Andreas; Bharathan, Desikan

    2007-03-13

    A power module assembly with low thermal resistance and enhanced heat dissipation to a cooling medium. The assembly includes a heat sink or spreader plate with passageways or openings for coolant that extend through the plate from a lower surface to an upper surface. A circuit substrate is provided and positioned on the spreader plate to cover the coolant passageways. The circuit substrate includes a bonding layer configured to extend about the periphery of each of the coolant passageways and is made up of a substantially nonporous material. The bonding layer may be solder material which bonds to the upper surface of the plate to provide a continuous seal around the upper edge of each opening in the plate. The assembly includes power modules mounted on the circuit substrate on a surface opposite the bonding layer. The power modules are positioned over or proximal to the coolant passageways.

  1. Atomic layer deposition of alternative glass microchannel plates

    International Nuclear Information System (INIS)

    The technique of atomic layer deposition (ALD) has enabled the development of alternative glass microchannel plates (MCPs) with independently tunable resistive and emissive layers, resulting in excellent thickness uniformity across the large area (20 × 20 cm), high aspect ratio (60:1 L/d) glass substrates. Furthermore, the use of ALD to deposit functional layers allows the optimal substrate material to be selected, such as borosilicate glass, which has many benefits compared to the lead-oxide glass used in conventional MCPs, including increased stability and lifetime, low background noise, mechanical robustness, and larger area (at present up to 400 cm2). Resistively stable, high gain MCPs are demonstrated due to the deposition of uniform ALD resistive and emissive layers on alternative glass microcapillary substrates. The MCP performance characteristics reported include increased stability and lifetime, low background noise (0.04 events cm−2 s−1), and low gain variation (±5%)

  2. ELECTROLESS NICKEL PLATING ON CHITOSAN-MODIFIED WOOD VENEER

    Directory of Open Access Journals (Sweden)

    Lijuan Wang

    2011-04-01

    Full Text Available An activation process involving chitosan was conducted to prepare electroless nickel plated wood veneers for electromagnetic interference (EMI shielding. In this process Pd(Ⅱ ions were chemically adsorbed on wood surface modified with chitosan. Then they were reduced and dipped into a plating bath in which Ni-P co-deposition was successfully initiated. The coatings were characterized by SEM-EDS and XRD. The metal deposition, surface resistivity, and electromagnetic shielding effectiveness were measured. The morphology of the coating observed by SEM was uniform, compact, and continuous. EDS results showed that the coating consists of 1.8 wt.% phosphorus and 98.2 wt.% nickel. XRD analysis indicated that the coating was crystalline, which is supposed to be related to the low phosphorus content. The plated birch veneers exhibited electro-conductivity with surface resistivity of 0.24 Ω•cm-2 and good electromagnetic shielding effectiveness of over 50 dB in frequency range from10 MHz to 1.5 GHz.

  3. Scintillating glass, fiber-optic plate detectors for tracking applications

    International Nuclear Information System (INIS)

    The authors studied the performance of scintillating glass fiber-optic plates using high energy particle beams at SLAC, Fermilab, and the ANLIPNS facility. The plates were composed of silicate glasses containing: (1) 5.4 weight % of Tb2O3 in cladded-glass fibers in a matrix of 15 μm spacing; and (2) 0.6 mole % of Ce2O3 in cladded-glass fibers in matrices of 10 μm and 25 μm spacing. The plates were viewed with a three-stage image intensifier. Particle tracks and nuclear interactions were recorded on film. The authors observed 5 detected hitsmm for minimum ionizing particles in the Tb glass, and -- 2 hitsmm for Ce glass. Preliminary measurements of attenuation length and radiation resistance properties of the Cerium glass which are of particular importance for collider applications, indicate that λ/sub atten/ > 10 cm for 10 μm diameter fibers and that dose rates in excess of 107 rads over a period of several days lead to a 20% loss of optical transmission near peak fluorescence (390 nm). The results of all these tests indicate that scintillating glass fiber-optic plates can be used in high spatial resolution tracking detectors for both fixed target and colliding beam experiments, and (in the case of Ce2O3 glass) high luminosity environments

  4. Surface stability and conductivity of a high Cr and Ni austenitic stainless steel plates for PEMFC

    Institute of Scientific and Technical Information of China (English)

    TIAN Rujin; SUN Juncai; WANG Jianli

    2006-01-01

    In order to use stainless steel as bipolar plate for PEMFC, electrochemical behavior of a high Cr and Ni austenitic stainless steel was studied in the solutions containing different concentration of H2SO4 and 2 mg·L-1 F-, and interfacial contact resistance was measured after corrosion tests. The experimental results show that the passive current density lowers with decreasing the concentration of H2SO4. The interfacial contact resistance between carbon paper and passive film formed in the simulated PEMFC environment is higher than the goal of bipolar plate for PEMFC. Surface conductivity should be further reduced by surface modification.

  5. Measurement procedure for optomechanical hole plate

    DEFF Research Database (Denmark)

    Larsen, Erik

    2003-01-01

    Measurement procedure for optomechanical hole plate in connection with CIRP interlaboratory comparison on measuring machines.......Measurement procedure for optomechanical hole plate in connection with CIRP interlaboratory comparison on measuring machines....

  6. Earth's Decelerating Tectonic Plates

    Energy Technology Data Exchange (ETDEWEB)

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  7. Thermoelastic bending of locally heated composite plate

    OpenAIRE

    Жидик, Уляна

    2013-01-01

    The dynamic behavior of composite plates to rapid heating is investigated. A closed form solutions are presented for simply supported rectangular cross-ply and angle-ply laminated plates. Numerical results are finally presented and discussed.

  8. Airflow resistivity of models of fibrous acoustic materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    resistivity are given, which are valid for the cylinder (fiber) concentrations found in acoustic materials. A one-dimensional model consisting of parallel plates with random spacing between the plates is first discussed. Then a two-dimensional model consisting of parallel cylinders randomly spaced is treated...

  9. Mathematical methods for elastic plates

    CERN Document Server

    Constanda, Christian

    2014-01-01

    Mathematical models of deformation of elastic plates are used by applied mathematicians and engineers in connection with a wide range of practical applications, from microchip production to the construction of skyscrapers and aircraft. This book employs two important analytic techniques to solve the fundamental boundary value problems for the theory of plates with transverse shear deformation, which offers a more complete picture of the physical process of bending than Kirchhoff’s classical one.   The first method transfers the ellipticity of the governing system to the boundary, leading to singular integral equations on the contour of the domain. These equations, established on the basis of the properties of suitable layer potentials, are then solved in spaces of smooth (Hölder continuous and Hölder continuously differentiable) functions.   The second technique rewrites the differential system in terms of complex variables and fully integrates it, expressing the solution as a combination of complex ana...

  10. Dielectrophoretically controlled Fresnel zone plate.

    Science.gov (United States)

    Chrimes, A F; Khodasevych, I; Mitchell, A; Rosengarten, G; Kalantar-zadeh, K

    2015-02-21

    Switchability is a highly sought after feature for planar optical systems. Suspensions of nanomaterials can be used for generating controllable changes in such systems. We report a planar diffractive microfluidic lens which integrates controlled dielectrophoresis (DEP) for trapping suspended nanomaterials. Silicon and tungsten oxide nanoparticle suspensions are used. These nanomaterials are trapped in such a way as to form alternating opaque and transparent rings using the DEP forces on demand. These rings form a planar diffractive Fresnel zone plate to focus the incident light. The Fresnel zone plate is tuned for the visible light region and the lens can be turned on (DEP applied) or off (DEP removed) in a controlled manner. This proof of concept demonstration can be further expanded for a variety of switchable optical devices and can be integrated with lab-on-a-chip and optofluidic devices. PMID:25524620

  11. Smaller plates, less food waste

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg; Schmidt, Karsten; Skov, Laurits Rhoden;

    With roughly one-third of food produced for human consumption lost or wasted globally (about 1.3 billion tons per year), the impact on the environment cannot be anymore neglected. Actions at all points in the production chain are now urgent, including reductions in food waste at home, by retailers...... pilot study was to investigate whether the size of the dishware would non-reflectively influence the amount of foods taken from an “ad-libitum” buffet and the resulting amount of waste. Sample consisted of Danish business leaders that took part in a congress in Copenhagen, Denmark. Two buffet tables...... this was for logistic reasons. All food waste was collected in designated trash bags (different colour in each floor) and weighted in bulk by students. Smaller plates appear to have decreased food waste by 26% compared to the standard sized plates at a single serving in a self-service eating setting...

  12. A novel preparation of silver-plated polyacrylonitrile fibers functionalized with antibacterial and electromagnetic shielding properties

    International Nuclear Information System (INIS)

    Highlights: • We propose a novel modification method to initiate silver electroless plating on PAN fiber without noble metal catalyst. • The silver-plated fiber we fabricated has good electromagnetic shielding effectiveness and antibacterial properties. • The metal layer has good adhesion strength and the properties of the silver-plated fiber can stand 30 cycles of standard washing. - Abstract: Polyacrylonitrile (PAN) fibers with antibacterial, electromagnetic shielding and antistatic functionalities were fabricated in this paper through modifying PAN fibers with (3-aminopropyl)triethoxysilane (APTES) and 3-mercaptopropyltriethoxysilane (MPTES) sequentially and followed with silver electroless plating. The silver layer on PAN fiber surface was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the silver layer was plated uniformly and compactly. The surface resistance of plated fabric was about 40 mΩ/sq on average. The antibacterial tests demonstrate that silver-plated PAN fiber exhibits excellent antibacterial property against S. aureus and E. coli with a non-leaching characteristic. The antibacterial property remains good after 30 cycles of standard washing, which is a strong proof of a durable adhesion between metal layer and fiber. The shielding effectiveness (SE) of silver-plated PAN fabric before and after 30 cycles of standard washing was about 40–80 dB and 35–50 dB, respectively. This resultant fiber can be used in many occasions for reducing or preventing electromagnetic interference (EMI) and electromagnetic hazards

  13. A novel preparation of silver-plated polyacrylonitrile fibers functionalized with antibacterial and electromagnetic shielding properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Li, Weiya; Gao, Cuicui; Tian, Weicheng [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Sun, Bin [College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Yu, Dan, E-mail: yudan@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China)

    2015-07-01

    Highlights: • We propose a novel modification method to initiate silver electroless plating on PAN fiber without noble metal catalyst. • The silver-plated fiber we fabricated has good electromagnetic shielding effectiveness and antibacterial properties. • The metal layer has good adhesion strength and the properties of the silver-plated fiber can stand 30 cycles of standard washing. - Abstract: Polyacrylonitrile (PAN) fibers with antibacterial, electromagnetic shielding and antistatic functionalities were fabricated in this paper through modifying PAN fibers with (3-aminopropyl)triethoxysilane (APTES) and 3-mercaptopropyltriethoxysilane (MPTES) sequentially and followed with silver electroless plating. The silver layer on PAN fiber surface was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the silver layer was plated uniformly and compactly. The surface resistance of plated fabric was about 40 mΩ/sq on average. The antibacterial tests demonstrate that silver-plated PAN fiber exhibits excellent antibacterial property against S. aureus and E. coli with a non-leaching characteristic. The antibacterial property remains good after 30 cycles of standard washing, which is a strong proof of a durable adhesion between metal layer and fiber. The shielding effectiveness (SE) of silver-plated PAN fabric before and after 30 cycles of standard washing was about 40–80 dB and 35–50 dB, respectively. This resultant fiber can be used in many occasions for reducing or preventing electromagnetic interference (EMI) and electromagnetic hazards.

  14. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2014-05-20

    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  15. A tandem parallel plate analyzer

    International Nuclear Information System (INIS)

    By a new modification of a parallel plate analyzer the second-order focus is obtained in an arbitrary injection angle. This kind of an analyzer with a small injection angle will have an advantage of small operational voltage, compared to the Proca and Green analyzer where the injection angle is 30 degrees. Thus, the newly proposed analyzer will be very useful for the precise energy measurement of high energy particles in MeV range. (author)

  16. The origin of background plating

    OpenAIRE

    Braun, Stefan; Zuschlag, Annika; Raabe, Bernd; Hahn, Giso

    2011-01-01

    In the last years efforts were made to overcome the widespread screen printing metallization technique to reduce shading of the front side, increase the finger conductivity, and improve the contact properties of the metallization of crystalline silicon solar cells. A promising approach is plating via wet chemical metal deposition. Hereby, the metals nickel as contact layer and copper or silver as conduction layer are alternatives to the thick film screen printing process. One challenge using ...

  17. Electroless metal plating of plastics

    Science.gov (United States)

    Krause, Lawrence J.

    1984-01-01

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  18. Episodic plate tectonics on Venus

    Science.gov (United States)

    Turcotte, Donald

    1992-01-01

    Studies of impact craters on Venus from the Magellan images have placed important constraints on surface volcanism. Some 840 impact craters have been identified with diameters ranging from 2 to 280 km. Correlations of this impact flux with craters on the Moon, Earth, and Mars indicate a mean surface age of 0.5 +/- 0.3 Ga. Another important observation is that 52 percent of the craters are slightly fractured and only 4.5 percent are embayed by lava flows. These observations led researchers to hypothesize that a pervasive resurfacing event occurred about 500 m.y. ago and that relatively little surface volcanism has occurred since. Other researchers have pointed out that a global resurfacing event that ceased about 500 MYBP is consistent with the results given by a recent study. These authors carried out a series of numerical calculations of mantle convection in Venus yielding thermal evolution results. Their model considered crustal recycling and gave rapid planetary cooling. They, in fact, suggested that prior to 500 MYBP plate tectonics was active in Venus and since 500 MYBP the lithosphere has stabilized and only hot-spot volcanism has reached the surface. We propose an alternative hypothesis for the inferred cessation of surface volcanism on Venus. We hypothesize that plate tectonics on Venus is episodic. Periods of rapid plate tectonics result in high rates of subduction that cool the interior resulting in more sluggish mantle convection.

  19. Modified tubularized incised plate urethroplasty

    Directory of Open Access Journals (Sweden)

    Shivaji Mane

    2013-01-01

    Full Text Available Aim: To share our experience of doing tubularized incised plate urethroplasty with modifications. Materials and Methods: This is a single surgeon personal series from 2004 to 2009. One hundred patients of distal hypospadias were subjected for Snodgrass urethroplasty with preputioplasty. The age range was 1 to 5 year with mean age of 2.7 years. Selection criteria were good urethral plate, without chordee and torsion needing complete degloving. Main technical modification from original Snodgrass procedure was spongioplasty, preputioplasty, and dorsal slit when inability to retract prepuce during surgery. Results: Average follow-up period is 23 months. Seven (7% patients developed fistula and one patient had complete preputial dehiscence. Phimosis developed in three (3% patients and required circumcision. Dorsal slit was required in seven patients. One patient developed meatal stenosis in postoperative period. All other patients are passing single urinary stream and have cosmesis that is acceptable. Conclusions: Modified tubularized incised plate urethroplasty with preputioplasty effectively gives cosmetically normal looking penis with low complications.

  20. Study of uranium-electric plating measured

    International Nuclear Information System (INIS)

    The plate-thickness of transform target (enriched Uranium-electric plating and depleted Uranium-electric plating) have been measured using Back to Back Ionization Chamber, Small solid angle device and Au-si surface barrier Semi-conductor. Also, the uncertainties in the experiment was analysed. (authors)

  1. Making of uranium plating for detector

    International Nuclear Information System (INIS)

    Solid track spark auto counter was always used to measure fission rate in neutron character experiment, the key part-transform target is plating (depleted Uranium and enriched Uranium). The plating was made with electric plating. The facture technics and methods is introduced, also the experiment result was analysed and discussed. (authors)

  2. Moving Divertor Plates in a Tokamak

    International Nuclear Information System (INIS)

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions

  3. Moving Divertor Plates in a Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  4. 49 CFR 213.123 - Tie plates.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tie plates. 213.123 Section 213.123 Transportation... TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5 track where timber crossties are in use there shall be tie plates under the running rails on at least eight...

  5. One-step pickling-activation before magnesium alloy plating

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-juan; YU Gang; OUYANG Yue-jun; HE Xiao-mei; ZHANG Jun; YE Li-yuan

    2009-01-01

    A one-step pickling-activation process was proposed as an environmental friendly pretreatment method in phosphate-permanganate solution before electroplating on magnesium alloys. The effects of pickling-activation on qualities of coating were assessed by adhesion and porosity testing of copper plating. The interfacial reactions between specimen and solution were analyzed with SEM, EDX and XRD. The results show that the developed process of pickling-activation can equalize the potentials on substrate surface. The compacted zinc film can be obtained by zinc immersion after treating magnesium alloy in the pH 4-6 phosphate-permanganate solution for 3-5 min. The adhesion and corrosion resistance of copper plating are enhanced. The one-step pickling-activation can replace the existing two-step process of acid pickling and activation which contains a great deal of chromium and fluorine. The procedure of surface pretreatment is simplified and the production environment is improved.

  6. Semi-infinite plates dragged through granular beds

    International Nuclear Information System (INIS)

    We perform physical experiments and 2D discrete element method (DEM) simulations of semi-infinite plates dragged through granular beds at low speeds. The plate’s displacement, x, creates a growing surcharge in front of the plate (pile-up) that takes the shape of a wedge. The cross-sectional area of the pile-up wedge is proportional to xZ where Z is the immersion depth and the drag resistance increases from its yielding value with xZ. We extend the classical Coulomb earth pressure theory for yielding walls to account for the piling-up effect and find good agreement with simulations and physical measurements. (paper)

  7. Plate tectonics, habitability and life

    Science.gov (United States)

    Spohn, Tilman; Breuer, Doris

    2016-04-01

    The role of plate tectonics in defining habitability of terrestrial planets is being increasingly discussed (e.g., Elkins-Tanton, 2015). Plate tectonics is a significantly evolved concept with a large variety of aspects. In the present context, cycling of material between near surface and mantle reservoirs is most important. But increased heat transport through mixing of cold lithosphere with the deep interior and formation of continental crust may also matter. An alternative mechanism of material cycling between these reservoirs is hot-spot volcanism combined with crust delamination. Hot-spot volcanism will transport volatiles to the atmosphere while delamination will mix crust, possibly altered by sedimentation and chemical reactions, with the mantle. The mechanism works as long as the stagnant lithosphere plate has not grown thicker than the crust and as long as volcanic material is added onto the crust. Thermal evolution studies suggest that the mechanism could work for the first 1-2 Ga of planetary evolution. The efficiency of the mechanism is limited by the ratio of extrusive to intrusive volcanism, which is thought to be less than 0.25. Plate tectonics would certainly have an advantage by working even for more evolved planets. A simple, most-used concept of habitability requires the thermodynamic stability of liquid water on the surface of a planet. Cycling of CO2between the atmosphere, oceans and interior through subduction and surface volcanism is an important element of the carbonate-silicate cycle, a thermostat feedback cycle that will keep the atmosphere from entering into a runaway greenhouse. Calculations for a model Earth lacking plate tectonics but degassing CO2, N, and H2O to form a surface ocean and a secondary atmosphere (Tosi et al, 2016) suggest that liquid water can be maintained on the surface for 4.5Ga. The model planet would then qualify as habitable. It is conceivable that the CO2 buffering capability of its ocean together with silicate

  8. Plate-Based Fuel Processing System Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Carlos Faz; Helen Liu; Jacques Nicole; David Yee

    2005-12-22

    On-board reforming of liquid fuels into hydrogen is an enabling technology that could accelerate consumer usage of fuel cell powered vehicles. The technology would leverage the convenience of the existing gasoline fueling infrastructure while taking advantage of the fuel cell efficiency and low emissions. Commercial acceptance of on-board reforming faces several obstacles that include: (1) startup time, (2) transient response, and (3) system complexity (size, weight and cost). These obstacles are being addressed in a variety of projects through development, integration and optimization of existing fuel processing system designs. In this project, CESI investigated steam reforming (SR), water-gas-shift (WGS) and preferential oxidation (PrOx) catalysts while developing plate reactor designs and hardware where the catalytic function is integrated into a primary surface heat exchanger. The plate reactor approach has several advantages. The separation of the reforming and combustion streams permits the reforming reaction to be conducted at a higher pressure than the combustion reaction, thereby avoiding costly gas compression for combustion. The separation of the two streams also prevents the dilution of the reformate stream by the combustion air. The advantages of the plate reactor are not limited to steam reforming applications. In a WGS or PrOx reaction, the non-catalytic side of the plate would act as a heat exchanger to remove the heat generated by the exothermic WGS or PrOx reactions. This would maintain the catalyst under nearly isothermal conditions whereby the catalyst would operate at its optimal temperature. Furthermore, the plate design approach results in a low pressure drop, rapid transient capable and attrition-resistant reactor. These qualities are valued in any application, be it on-board or stationary fuel processing, since they reduce parasitic losses, increase over-all system efficiency and help perpetuate catalyst durability. In this program, CESI

  9. Peridinialean dinoflagellate plate patterns, labels and homologies

    Science.gov (United States)

    Edwards, L.E.

    1990-01-01

    Tabulation patterns for peridinialean dinoflagellate thecae and cysts have been traditionally expressed using a plate labelling system described by C.A. Kofoid in the early 1900's. This system can obscure dinoflagellate plate homologies and has not always been strictly applied. The plate-labelling system presented here introduces new series labels but incorporates key features and ideas from the more recently proposed systems of G.L. Eaton and F.J.R. Taylor, as modified by W.R. Evitt. Plate-series recognition begins with the cingulum (C-series) and proceeds from the cingulum toward the apex for the three series of the epitheca/epicyst and proceeds from the cingulum toward the antapex for the two series of the hypotheca/hypocyst. The epithecal/epicystal model consists of eight plates that touch the anterior margin of the cingulum (E-series: plates E1-E7, ES), seven plates toward the apex that touch the E-series plates (M-series: R, M1-M6), and up to seven plates near the apex that do not touch E-series plates (D-series: Dp-Dv). The hypothecal/hypocystal model consists of eight plates that touch the posterior margin of the cingulum (H-series: H1-H6,HR,HS) and three plates toward the antapex (T1-T3). Epithecal/epicystal tabulation patterns come in both 8- and 7- models, corresponding to eight and seven plates, respectively, in the E-series. Hypothecal/hypocystal tabulation patterns also come in both 8- and 7-models, corresponding to eight and seven plates, respectively, in the H-series. By convention, the 7-model epitheca/epicyst has no plates E1 and M1; the 7-model hypotheca/hypocyst has no plate H6. Within an 8-model or 7-model, the system emphasizes plates that are presumed to be homologous by giving them identical labels. I introduce the adjectives "monothigmate", "dithigmate," and "trithigmate" to designate plates touching one, two, and three plates, respectively, of the adjacent series. The term "thigmation" applies to the analysis of plate contacts between

  10. Polyaniline and polypyrrole coatings on aluminum for PEM fuel cell bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Shine; McClure, J.C. [Metallurgical and Materials Department, University of Texas El Paso, El Paso, TX (United States); Sebastian, P.J. [Centro de Investigation en Energia, UNAM, Temixco, Morelos (Mexico); CAES, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Moreira, J.; Valenzuela, Edgar [CAES, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2008-02-15

    The conducting polymers polypyrrole and polyaniline were deposited on 6061 aluminum using cyclic voltammetry and painting, respectively. These samples are intended for proton exchange membrane fuel cell applications where surface contact resistance as well as bulk corrosion resistance are requirements for the bipolar plates that separate the cells. Corrosion current and voltage were measured on the samples as well as contact resistance between coated samples as a function of contact pressure. The polypyrrole samples showed neither improved corrosion resistance nor acceptable contact resistance. The painted polyaniline samples, however, showed about an order of magnitude reduction in corrosion current with only a minor increase in contact resistance. It is believed that in the more acidic environment of a fuel cell, the polyaniline will become even more conductive and that further reduction in contact resistance should be possible. (author)

  11. Development and characterization of single gap glass RPC

    CERN Document Server

    Manisha,; Shahi, J S; Singh, J B

    2016-01-01

    The India-based Neutrino Observatory (INO) collaboration is going to build a 50 kton magnetized Iron CALorimeter (ICAL) detector for the precise measurement of neutrino oscillations using atmospheric neutrinos. The proposed ICAL detector will be a stack of magnetized iron plates (acting as target material) interleaved with the glass Resistive Plate Chambers (RPCs)as active elements. RPC is a gaseous detector made up of two parallel electrodes having high bulk resistivity like that of the float glass and bakelite. For ICAL detector, glass is preferred over bakelite as it does not need any kind of surface treatment to achieve better surface uniformity and also the cost of detector is reduced. Under detector R&D efforts for the proposed detector, we have fabricated the glass RPCs of 1m X 1m in size procuring glass of ~ 2 mm thickness from one of the Indian glass manufacturers (Asahi). In the present characterization studies, we report on the leakage current, pulse width optimization for the measurements of e...

  12. Design of grid plate and support structure

    International Nuclear Information System (INIS)

    The grid plate in the fast reactor vessel is a perforated plate with about 800 circular holes supporting the fuel and blanket sub-assemblies. It transfers this load to the reactor vessel through a support structure. In a typical arrangement, the grid plate is suspended from the vessel walls. The plate is immersed in liquid sodium at 4000 C and is loaded by dead weight of the core, sodium pressure and a certain number of thermal shocks. It is required to analyse the deflection, slope and stresses in the plate and support structure. In particular, the stress concentration analysis has to be carried out. (author)

  13. Separator plate for a fuel cell

    Science.gov (United States)

    Petri, Randy J.; Meek, John; Bachta, Robert P.; Marianowski, Leonard G.

    1996-01-01

    A separator plate for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced.

  14. Gradient Plate for Hicomb Minimum Inhibitory Concentration (MIC Test

    Directory of Open Access Journals (Sweden)

    Fatemi Motlagh M

    2011-01-01

    Full Text Available Bakground and objectives: "The comb antibiotic sensitivity test" is a quick,reliable and cost effective method to determine the susceptibility of bacteriato different antibiotics. The purpose of this study is to design a plate that iseasy and quick to use, and enable to be interpreted easily without the need formeasurement of the margins with a ruler.Material and Methods: First, Clinical and Laboratory Standards Institutedata about the maximum growth inhibitory haloes formed with antibioticsand various micro-organisms were statistically examined and determinedthat the most (99.7% zone of inhibition growth is formed in the range of 42mm. Accordingly, the obtained number (42 mm and conventional plate size(100 mm used for testing sensitivity were punched into Solid workssoftware which was used to determine the best place of strip and shoulderplates. After that the efficacy this media were examined by determination ofMIC Staphylococcus aureus and Klebsiella pneumonia, non-graded andgraded plate shoulders were searched and compared.Results: Has been placed two combs MIC in a plate in this method anddidn’t create growth inhibitory haloes interferences. Obtained MIC forNitrofurantoin( 10 μg/ml , Amikacin(0.5 μg/ml, Gentamicin(1 μg/ml , andAmoxicillin (0.5 μg/ml against S.aureus , MIC Nalidicsic Acid, Amikcin,Gentamicin and Nitrofurantoin against K.pneumonia was 0.1, 0.5, 0.5 and 10μg/ml ,respectively.Conclusion:The comparison between this new innovative method andstandard methods (Clinical Laboratory Standards Institute - CLSI shows thatthere a marked reduction in the interference of antibiotic therapy and willalso reduce time of interpretation.Key words: Plate, Antibiogram Comb, MIC, Antibiotics, Drug resistance

  15. Shear deformation in thick auxetic plates

    International Nuclear Information System (INIS)

    This paper aims to understand the effect of auxeticity on shear deformation in thick plates. Three models for the shear correction factor of plates as a function of Poisson’s ratio were proposed: an analytical model, a cubic fit model and a modified model. Of these three, the cubic fit model exhibits the best accuracy over the entire range of Poisson’s ratio from −1 to 0.5. The extent of shear deformation is herein investigated using the example of uniformly loaded circular plates. It was found that the maximum deformation of such plates based on Mindlin theory approximates to those according to Kirchhoff theory when the Poisson’s ratio of the plate material is highly negative. When the Poisson’s ratio of the plate material is −1 and the edge of the plate is simply supported, the calculation of the maximum deflection by Mindlin theory simplifies into that by Kirchhoff theory. These results suggest that auxeticity reduces shear deformation in thick plates, permitting the use of classical plate theory for thick plates only if the plate material is highly auxetic. (paper)

  16. Hierarchical self-organization of tectonic plates

    CERN Document Server

    Morra, Gabriele; Müller, R Dietmar

    2010-01-01

    The Earth's surface is subdivided into eight large tectonic plates and many smaller ones. We reconstruct the plate tessellation history and demonstrate that both large and small plates display two distinct hierarchical patterns, described by different power-law size-relationships. While small plates display little organisational change through time, the structure of the large plates oscillate between minimum and maximum hierarchical tessellations. The organization of large plates rapidly changes from a weak hierarchy at 120-100 million years ago (Ma) towards a strong hierarchy, which peaked at 65-50, Ma subsequently relaxing back towards a minimum hierarchical structure. We suggest that this fluctuation reflects an alternation between top and bottom driven plate tectonics, revealing a previously undiscovered tectonic cyclicity at a timescale of 100 million years.

  17. PWR integral tie plate and locking mechanism

    International Nuclear Information System (INIS)

    A locking mechanism for securing an upper tie plate to the tie rods of a nuclear fuel bundle is described. The mechanism includes an upper tie plate assembly and locking sleeves fixed to the ends of the tie rods. The tie plate is part of the upper tie plate assembly and is secured to the fuel bundle by securing the entire upper tie plate assembly to the locking sleeves fixed to the tie rods. The assembly includes, in addition to the tie plate, locking nuts for engaging the locking sleeves, retaining sleeves to operably connect the locking nuts to the assembly, a spring biased reaction plate to restrain the locking nuts in the locked position and a means to facilitate the removal of the entire assembly as a unit from the fuel bundle

  18. Investigation into the aerodynamic processes of air treatment using a plate-type biofilter.

    Science.gov (United States)

    Baltrėnas, Pranas; Kleiza, Jonas; Idzelis, Raimondas Leopoldas

    2016-03-01

    The research conducted has involved a laboratory stand of a plate-type air treatment biofilter with a capillary system for humidifying packing material composed of polymer plates vertically arranged next to each other and producing a capillary effect of humidification. The pattern of arranging the plates has sufficiently large spaces (6 mm), and therefore the use of the plate-type structure decreases the aerodynamic resistance of the device. Slightly pressed slabs attached on both sides of the plates are made of heat-treated wood fibre, to increase the longevity of which, wood waste has been heat-treated in the steam explosion reactor under the pressure of 32 bars and a temperature of 235°C. This is the method for changing the molecular structure of wood, which stops the decay of wood fibre in a humid environment and thus increases the life span of biofilter plates. The research performed has disclosed that, under the application of the above introduced structure of the biofilter, the aerodynamic resistance of the biofilter reaches 1 ÷ 5 Pa when the rate of the air flow passing through the device makes 0.08 m/s. For evaluating the reliability of the obtained results, the theoretical model has been applied. PMID:26207569

  19. Experimental study on behavior of RC panels covered with steel plates subjected to missile impact

    International Nuclear Information System (INIS)

    This paper describes an experimental study on the behavior of concrete panels with steel plate subjected to missile impact. Two tests were carried out, divided in accordance with the types of projectile, non-deformable and deformable. In all, 40 specimens of 750 mm square were prepared. The panel specimen was suspended vertically by two steel wire ropes to allow free movement after projectile impact, and was subjected to a projectile. As a result, it is confirmed that a RC panel with steel plate on its back side has higher impact resistance performance than a RC panel and that thickness of concrete panel, thickness of steel plate and the impact velocity of the projectile have a great effect on the failure modes of steel concrete panels. Moreover, based on the experimental results, the quantitative evaluation method for impact resistance performance of RC panels covered with steel plates is examined. The formula for perforation velocity of a half steel concrete panel, proposed in accordance with the bulging height, is effective to evaluate the impact resistance performance of RC panels with steel plates. (authors)

  20. Tectonic speed limits from plate kinematic reconstructions

    Science.gov (United States)

    Zahirovic, Sabin; Müller, R. Dietmar; Seton, Maria; Flament, Nicolas

    2015-05-01

    The motion of plates and continents on the planet's surface are a manifestation of long-term mantle convection and plate tectonics. Present-day plate velocities provide a snapshot of this ongoing process, and have been used to infer controlling factors on the speeds of plates and continents. However, present-day velocities do not capture plate behaviour over geologically representative periods of time. To address this shortcoming, we use a plate tectonic reconstruction approach to extract time-dependent plate velocities and geometries from which root mean square (RMS) velocities are computed, resulting in a median RMS plate speed of ∼ 4 cm /yr over 200 Myr. Linking tectonothermal ages of continental lithosphere to the RMS plate velocity analysis, we find that the increasing portions of plate area composed of continental and/or cratonic lithosphere significantly reduces plate speeds. Plates with any cratonic portion have a median RMS velocity of ∼ 5.8 cm /yr, while plates with more than 25% of cratonic area have a median RMS speed of ∼ 2.8 cm /yr. The fastest plates (∼ 8.5 cm /yr RMS speed) have little continental fraction and tend to be bounded by subduction zones, while the slowest plates (∼ 2.6- 2.8 cm /yr RMS speed) have large continental fractions and usually have little to no subducting part of plate perimeter. More generally, oceanic plates tend to move 2-3 times faster than continental plates, consistent with predictions of numerical models of mantle convection. The slower motion of continental plates is compatible with deep keels impinging on asthenospheric flow and increasing shear traction, thus anchoring the plate in the more viscous mantle transition zone. We also find that short-lived (up to ∼ 10 Myr) rapid accelerations of Africa (∼100 and 65 Ma), North America (∼100 and 55 Ma) and India (∼ 130 , 80 and 65 Ma) appear to be correlated with plume head arrivals as recorded by large igneous province (LIPs) emplacement. By evaluating

  1. Stretching morphogenesis of the roof plate and formation of the central canal.

    Directory of Open Access Journals (Sweden)

    Igor Kondrychyn

    Full Text Available BACKGROUND: Neurulation is driven by apical constriction of actomyosin cytoskeleton resulting in conversion of the primitive lumen into the central canal in a mechanism driven by F-actin constriction, cell overcrowding and buildup of axonal tracts. The roof plate of the neural tube acts as the dorsal morphogenetic center and boundary preventing midline crossing by neural cells and axons. METHODOLOGY/PRINCIPAL FINDINGS: The roof plate zebrafish transgenics expressing cytosolic GFP were used to study and describe development of this structure in vivo for a first time ever. The conversion of the primitive lumen into the central canal causes significant morphogenetic changes of neuroepithelial cells in the dorsal neural tube. We demonstrated that the roof plate cells stretch along the D-V axis in parallel with conversion of the primitive lumen into central canal and its ventral displacement. Importantly, the stretching of the roof plate is well-coordinated along the whole spinal cord and the roof plate cells extend 3× in length to cover 2/3 of the neural tube diameter. This process involves the visco-elastic extension of the roof place cytoskeleton and depends on activity of Zic6 and the Rho-associated kinase (Rock. In contrast, stretching of the floor plate is much less extensive. CONCLUSIONS/SIGNIFICANCE: The extension of the roof plate requires its attachment to the apical complex of proteins at the surface of the central canal, which depends on activity of Zic6 and Rock. The D-V extension of the roof plate may change a range and distribution of morphogens it produces. The resistance of the roof plate cytoskeleton attenuates ventral displacement of the central canal in illustration of the novel mechanical role of the roof plate during development of the body axis.

  2. Double coating protection of Nd–Fe–B magnets: Intergranular phosphating treatment and copper plating

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jingwu; Chen, Haibo; Qiao, Liang [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Lin, Min [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering Chinese Academy of Science, Ningbo 315201 (China); Jiang, Liqiang; Che, Shenglei [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Hu, Yangwu, E-mail: 346648086@qq.com [College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Wenzhou Institute of Industry and Science, Wenzhou 325000 (China)

    2014-12-15

    In this work, a double coating protection technique of phosphating treatment and copper plating was made to improve the corrosion resistance of sintered Nd–Fe–B magnets. In other words, the intergranular region of sintered Nd–Fe–B is allowed to generate passive phosphate conversion coating through phosphating treatment, followed by the copper coating on the surface of sintered Nd–Fe–B. The morphology and corrosion resistance of the phosphated sintered Nd–Fe–B were observed using SEM and electrochemical method respectively. The phosphate conversion coating was formed more preferably on the intergranular region of sintered Nd–Fe–B than on the main crystal region; just after a short time of phosphating treatment, the intergranular region of sintered Nd–Fe–B has been covered by the phosphate conversion coating and the corrosion resistance is significantly improved. With the synergistic protection of the intergranular phosphorization and the followed copper electrodeposition, the corrosion resistance of the sintered Nd–Fe–B is significantly better than that with a single phosphate film or single plating protection. - Highlights: • We combined intergranular phosphating and copper plating to protect Nd–Fe–B. • The phosphate conversion coating was formed preferably on the intergranular region. • The phosphating coating can obviously improve the corrosion resistance of Nd–Fe–B. • The corrosion resistance of Nd–Fe–B was improved by double coating protection.

  3. Antibiotic Resistance

    Science.gov (United States)

    Antibiotics are medicines that fight bacterial infections. Used properly, they can save lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able to resist the effects of an antibiotic. Using antibiotics can lead to resistance. ...

  4. Feasibility study on development of plate-type heat exchanger for BWR plants

    International Nuclear Information System (INIS)

    In order to apply plate-type heat exchanger to RCW, TCW and FPC system in BWR plants, heat test and seismic test of RCW system heat exchanger sample were carried out. The results of these tests showed new design plate-type heat exchanger satisfied the fixed pressure resistance and seismic resistance and keep the function. The evaluation method of seismic design was constructed and confirmed by the results of tests. As anti-adhesion measure of marine organism, an ozone-water circulation method, chemical-feed method and combination of circulation of hot water and air bubbling are useful in place of the chlorine feeding method. Application of the plate-type heat exchanger to BWR plant is confirmed by these investigations. The basic principles, structure, characteristics, application limit and reliability are stated. (S.Y.)

  5. Shock wave interaction with porous plates

    Energy Technology Data Exchange (ETDEWEB)

    Skews, Beric [University of the Witwatersrand, School of Mechanical, Industrial, and Aeronautical Engineering, Johannesburg (South Africa)

    2005-11-01

    Previous detailed studies of the interaction of a shock wave with a perforated sheet considered the impact of a shock wave on a plate with regularly spaced slits giving area blockages of 60 and 67%, at various angles of incidence, and resulting in both regular and Mach reflection. The current work extends this study to a much wider variety of plate geometries. Blockage ratios of 20, 25, 33, 50, and 67 and inclinations of 45, 60, 75, and 90 to the shock wave were tested. Four different thicknesses of plate were tested at the same frontal blockage in order to assess the effects of gap guidance. Tests were conducted at two shock Mach numbers of 1.36 and 1.51 (inverse pressure ratios of 0.4 and 0.5). It is found that secondary reflected and transmitted waves appear due to the complex interactions within the grid gaps, and that the vortex pattern which is generated under the plate is also complex due to these interactions. The angle of the reflected shock, measured relative to the plate, decreases with plate blockage and the angle of inflow to the plate reduces with increasing blockage. By analysing the flow on the underside of the plate the pseudo-steady flow assumption is found to be a reasonable approximation. Both the pressure difference and the stagnation pressure loss across the plate are evaluated. It is found that over the range tested the plate thickness has a minimal effect. (orig.)

  6. A Refined Shear Deformation Plate Theory

    Science.gov (United States)

    Liu, Yucheng

    2011-04-01

    An improved higher-order shear deformation theory of plates is presented in this paper. The theory is developed from the transverse shear deformation theory presented by Ambartsumian [11]. The present plate theory contains kinematics of higher-order displacement field of plates, a system of higher-order differential equilibrium equations in terms of the three generalized displacements of bending plates, and a system of boundary conditions at each edge of plate boundaries. The present shear deformation theory of plates is validated by applying it to solve torsional plates and simply supported plates. The obtained solutions using the present theory are compared with the solutions of other shear-deformation theories. A good agreement is achieved through these comparisons and the advantages of the present theory are clearly verified. The shear deformation plate theory presented here can be applied to the analysis of laminated composite plates to better predict their dynamic and static behaviors. The proposed theory should also be supplemented to the theory of finite element analysis for developing new shell elements.

  7. Preparation of Ag-coated hollow microspheres via electroless plating for application in lightweight microwave absorbers

    Science.gov (United States)

    Kim, Wook-Joong; Kim, Sung-Soo

    2015-02-01

    Highly conductive Ag film is coated on hollow silica microspheres via electroless plating for application in lightweight microwave absorbers. The Ag plating is conducted using a two-step process of sensitizing and subsequent plating. The complex permeability and permittivity are determined using the reflection/transmission technique in the composite specimens of Ag-coated microspheres and silicone rubber matrix. Due to the large surface area of the microspheres, a relatively high concentration of AgNO3 is required in order to achieve a uniform Ag coating. In addition, a low concentration of fructose reducing agent is recommended for slow plating. The apparent electrical resistance of the Ag-coated microspheres is strongly dependent on the grain morphology. The thin and uniform Ag-coated particles are characterized by their low electrical resistance, which is as low as 0.1 Ω. The lower the electrical resistance of the microspheres, the higher the dielectric constant of the composite specimens, which results from the enhanced space-charge polarization between the conductive microspheres. The microwave absorbance is enhanced with decreases in the electrical resistance of microspheres due to the increased dielectric loss.

  8. Seismic link at plate boundary

    Indian Academy of Sciences (India)

    Faical Ramdani; Omar Kettani; Benaissa Tadili

    2015-06-01

    Seismic triggering at plate boundaries has a very complex nature that includes seismic events at varying distances. The spatial orientation of triggering cannot be reduced to sequences from the main shocks. Seismic waves propagate at all times in all directions, particularly in highly active zones. No direct evidence can be obtained regarding which earthquakes trigger the shocks. The first approach is to determine the potential linked zones where triggering may occur. The second step is to determine the causality between the events and their triggered shocks. The spatial orientation of the links between events is established from pre-ordered networks and the adapted dependence of the spatio-temporal occurrence of earthquakes. Based on a coefficient of synchronous seismic activity to grid couples, we derive a network link by each threshold. The links of high thresholds are tested using the coherence of time series to determine the causality and related orientation. The resulting link orientations at the plate boundary conditions indicate that causal triggering seems to be localized along a major fault, as a stress transfer between two major faults, and parallel to the geothermal area extension.

  9. A numerical study of field plate configurations in RF SOI LDMOS transistors

    Science.gov (United States)

    Cortés, I.; Roig, J.; Flores, D.; Urresti, J.; Hidalgo, S.; Rebollo, J.

    2006-02-01

    The effect of the source field plate architecture on the static and dynamic electrical performances of SOI LDMOS transistors for RF applications is analysed in this paper. Three architectures are envisaged: source field plate SFP, extended gate field plate and independently biased field plate. Moreover, two different drift diffusion profiles are considered: shallow SDD and deep doped DDD diffusion. The resultant drift region is analytically modelled and the impact of geometrical and technological parameters on the transconductance value is determined by means of numerical simulation techniques. Finally, the dependence of the LDMOS capacitances on the field plate configuration is also studied. Simulation results show the trade-off between reliability and transconductance in each field plate configuration. In spite of the power efficiency improvement, the field plate biasing can significantly degrade the SOI LDMOS performances due to hot-carrier and self-heating effects. On the contrary, the SFP configuration leads to an enhanced reliability at the cost of the on-state resistance increase. The SFP structure with deep doped drift (DDD) diffusion provides the best performances in terms of cut-off frequency and self-heating degradation.

  10. Analytical modeling and experimental validation of a structurally integrated piezoelectric energy harvester on a thin plate

    Science.gov (United States)

    Aridogan, U.; Basdogan, I.; Erturk, A.

    2014-04-01

    Vibration-based energy harvesting using piezoelectric cantilevers has been extensively studied over the past decade. As an alternative to cantilevered harvesters, piezoelectric patch harvesters integrated to thin plates can be more convenient for use in marine, aerospace and automotive applications since these systems are often composed of thin plate-like structures with various boundary conditions. In this paper, we present analytical electroelastic modeling of a piezoelectric energy harvester structurally integrated to a thin plate along with experimental validations. The distributed-parameter electroelastic model of the thin plate with the piezoceramic patch harvester is developed based on Kirchhoff’s plate theory for all-four-edges clamped (CCCC) boundary conditions. Closed-form steady-state response expressions for coupled electrical output and structural vibration are obtained under transverse point force excitation. Analytical electroelastic frequency response functions (FRFs) relating the voltage output and vibration response to force input are derived and generalized for different boundary conditions. Experimental validation and extensive theoretical analysis efforts are then presented with a case study employing a thin PZT-5A piezoceramic patch attached on the surface of a rectangular aluminum CCCC plate. The importance of positioning of the piezoceramic patch harvester is discussed through an analysis of dynamic strain distribution on the overall plate surface. The electroelastic model is validated by a comparison of analytical and experimental FRFs for a wide range of resistive electrical boundary conditions. Finally, power generation performance of the structurally integrated piezoceramic patch harvester from multiple vibration modes is investigated analytically and experimentally.

  11. Modification of the aluminum for making offset printing plates

    Directory of Open Access Journals (Sweden)

    NENAD ILIC

    2000-12-01

    Full Text Available Aluminum as the base of offset printing plates should make good contact with wetting agents and the light sensitive layer and should be resistant to wear and cracking. In order to achieve this, the aluminum is roughened and eventually anodized. A thin, electrochemically deposited chromium layer is used as the non-printing element in bimetallic offset printing forms. Chromium shows excellent wettability and wear resistance. The possibility of chemical deposition of chromium on aluminum from an alkaline solution is examined in this paper. The presence of chromium was confirmed and measured by EDAX. A difference in the spectral reflection characteristic between chromium-treated and non-treated specimens was also detected. An influence of a chromium layer on an aluminum surface was examined by water drop spreading. Chromium-treated samples showed better wettability than non-treated samples, but they are less wettable than anodized samples.

  12. Quantitative computed tomography as a test of endurance for evaluation of bony plates; Utilizacao da tomografia computadorizada quantitativa como teste de resistencia para avaliacao de placas osseas

    Energy Technology Data Exchange (ETDEWEB)

    Melo Filho, E.V.; Costa, L.A.V.S.; Oliveira, D.C. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Freitas, P.M.C. [Escola de Veterinaria - Universidade Federal de Minas Gerais - Belo Horizonte, MG (Brazil); Teixeira, M.W.; Costa, F.S. [Universidade Federal Rural de Pernambuco - Recife, PE (Brazil)

    2012-06-15

    Quantitative computed tomography was used to determine the radiodensity of bony plates. The CT scans provided information regarding radiodensity of bony plates and allowed to verify the uniformity of bone mineral density in their scope. The proposed methodology should be considered as another tool for determining the resistance of these biomaterials. (author)

  13. Coupling between plate vibration and acoustic radiation

    Science.gov (United States)

    Frendi, Abdelkader; Maestrello, Lucio; Bayliss, Alvin

    1992-01-01

    A detailed numerical investigation of the coupling between the vibration of a flexible plate and the acoustic radiation is performed. The nonlinear Euler equations are used to describe the acoustic fluid while the nonlinear plate equation is used to describe the plate vibration. Linear, nonlinear, and quasi-periodic or chaotic vibrations and the resultant acoustic radiation are analyzed. We find that for the linear plate response, acoustic coupling is negligible. However, for the nonlinear and chaotic responses, acoustic coupling has a significant effect on the vibration level as the loading increases. The radiated pressure from a plate undergoing nonlinear or chaotic vibrations is found to propagate nonlinearly into the far-field. However, the nonlinearity due to wave propagation is much weaker than that due to the plate vibrations. As the acoustic wave propagates into the far-field, the relative difference in level between the fundamental and its harmonics and subharmonics decreases with distance.

  14. Rapidly Moving Divertor Plates In A Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S. Zweben

    2011-05-16

    It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ~10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.

  15. Rapidly Moving Divertor Plates In A Tokamak

    International Nuclear Information System (INIS)

    It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ∼10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.

  16. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  17. Replacement divider plate performance under LOCA loading

    Energy Technology Data Exchange (ETDEWEB)

    Huynk, H.M. [Quebec Hydro, Montreal, PQ (Canada); MClellan, G.H.; Schneider, W.G. [Babcock and Wilcox, Cambridge, ON (Canada)

    1997-07-01

    A primary divider plate in a nuclear steam generator is required to perform its partitioning function with a minimum of cross leakage, without degradation in operating performance and without loss of structural integrity resulting from normal and accident loading. The design of the replacement divider plate for normal operating conditions is discussed in some detail in reference 1 and 2. This paper describes the structural response of the replacement divider plate to the severe loading resulting from a burst primary pipe. The loads for which the divider plate structural performance must be evaluated are mild to severe differential pressure transients resulting from several postulated sizes and types of pipe break scenarios. In the unlikely event of a severe Loss of Coolant Accident (LOCA) the divider plate or parts thereof must not exit the steam generator nor completely block the outlet nozzle. For the milder LOCA loads, the integrity of the divider plate and seat bars must be maintained. Analysis for the milder LOCA loads was carried out employing a conservative approach which ignores the actual interaction between the structure and the primary fluid. For these load cases it was shown that the divider plate does not become disengaged from the seat bars. For the more severe pipe breaks, the thermal-hydraulic analysis was coupled iteratively with the structural analysis, thereby taking into account divider plate deformation, in order to obtain a better prediction of the behaviour of the divider plate. In this manner substantial reduction in divider plate response to the more severe LOCA loading was achieved. It has been shown that, for the case of a postulated large LOCA (100% reactor inlet header), the disengagement of the divider plate from the seat bars resulted in an opening smaller than 1% of the divider plate area. (author)

  18. Strain weakening enables continental plate tectonics

    OpenAIRE

    Gueydan, Frédéric; Précigout, Jacques; Montesi, Laurent G.J.

    2014-01-01

    International audience Much debate exists concerning the strength distribution of the continental lithosphere, how it controls lithosphere-scale strain localization and hence enables plate tectonics. No rheological model proposed to date is comprehensive enough to describe both the weakness of plate boundary and rigid-like behaviour of plate interiors. Here we show that the duality of strength of the lithosphere corresponds to different stages of microstructural evolution. Geological const...

  19. Sigmoid plate dehiscence: Congenital or acquired condition?

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhaohui, E-mail: lzhtrhos@163.com [Capital Medical University, Beijing Tongren Hospital, No 1 Dong Jiao Min Street, Dongcheng District, Beijing 100730 (China); Li, Jing, E-mail: lijingxbh@yahoo.com.cn [Capital Medical University, Beijing Tongren Hospital, No 1 Dong Jiao Min Street, Dongcheng District, Beijing 100730 (China); Zhao, Pengfei, E-mail: zhaopengf05@163.com [Capital Medical University, Beijing Friendship Hospital, No 95 Yongan Road, Xicheng District, Beijing 100050 (China); Lv, Han, E-mail: chrislvhan@126.com [Capital Medical University, Beijing Friendship Hospital, No 95 Yongan Road, Xicheng District, Beijing 100050 (China); Dong, Cheng, E-mail: derc007@sina.com [Capital Medical University, Beijing Friendship Hospital, No 95 Yongan Road, Xicheng District, Beijing 100050 (China); Liu, Wenjuan, E-mail: wenjuanliu@163.com [Jining No. 1 People' s Hospital, No. 6 Health Street, Jining 272100 (China); Wang, Zhenchang, E-mail: cjr.wzhch@vip.163.com [Capital Medical University, Beijing Friendship Hospital, No 95 Yongan Road, Xicheng District, Beijing 100050 (China)

    2015-05-15

    Highlights: • CT with multiplanar reformations can accurately display the sigmoid platet dehiscence. • The prevalence of sigmoid plate dehiscence was no significant difference among different age groups. • The size of sigmoid plate bony defects were not statistically different among different age groups. • The sigmoid plate dehiscence is more commonly a congenital than an acquired condition. - Abstract: Background and purpose: The imaging features of sigmoid plate dehiscence-induced pulsatile tinnitus have been presented. The origin of the sigmoid plate dehiscence, however, remains unclear. Our aim was to assess the prevalence and extent of sigmoid plate dehiscence on computed tomography (CT) images in multiple age groups to determine whether this condition is more likely to be congenital or acquired. Materials and methods: We retrospectively reviewed contrast-enhanced CT images of sigmoid plates of temporal bones in 504 patients. Each temporal bone was characterized as normal or dehiscent. Patients were then subcategorized into four age groups, and the prevalence and extent of dehiscent sigmoid plates in each group were calculated and compared. Results: Overall, 80 patients had sigmoid plate dehiscence, nine of whom had it bilaterally. In successively older age groups, the prevalences of sigmoid plate dehiscence were 18.9%, 20.1%, 14.5%, and 12.7%, respectively. Respective average anteroposterior bony defect diameters were 3.7 ± 1.7, 3.0 ± 1.3, 3.1 ± 1.5, and 3.0 ± 1.1 mm. Respective average vertical bony defect diameters were 3.6 ± 2.3, 2.6 ± 1.2, 3.2 ± 1.5, and 3.0 ± 1.7 mm. The prevalence and extent of sigmoid plate dehiscence were not statistically different among the four age groups. Conclusions: The similar radiologic prevalence and extent of dehiscent sigmoid plates among the age groups suggest that the dehiscence is more commonly a congenital than an acquired condition.

  20. Strain resolving method of composite plane plates

    Directory of Open Access Journals (Sweden)

    Ion FUIOREA

    2011-06-01

    Full Text Available The paper deals with the extension of isotropic plates problem to the case of composite plates. In order to perform it, the Kirchhoff-Love hypotheses were “softened” by some additional ones. Considering the constitutive laws for composite materials the stress functions were eliminated by using Cauchy equations. As a result a partial derivative equation in displacements was obtained. Finally the boundary condition formulation was extended for the case of complex composite plates.

  1. Sigmoid plate dehiscence: Congenital or acquired condition?

    International Nuclear Information System (INIS)

    Highlights: • CT with multiplanar reformations can accurately display the sigmoid platet dehiscence. • The prevalence of sigmoid plate dehiscence was no significant difference among different age groups. • The size of sigmoid plate bony defects were not statistically different among different age groups. • The sigmoid plate dehiscence is more commonly a congenital than an acquired condition. - Abstract: Background and purpose: The imaging features of sigmoid plate dehiscence-induced pulsatile tinnitus have been presented. The origin of the sigmoid plate dehiscence, however, remains unclear. Our aim was to assess the prevalence and extent of sigmoid plate dehiscence on computed tomography (CT) images in multiple age groups to determine whether this condition is more likely to be congenital or acquired. Materials and methods: We retrospectively reviewed contrast-enhanced CT images of sigmoid plates of temporal bones in 504 patients. Each temporal bone was characterized as normal or dehiscent. Patients were then subcategorized into four age groups, and the prevalence and extent of dehiscent sigmoid plates in each group were calculated and compared. Results: Overall, 80 patients had sigmoid plate dehiscence, nine of whom had it bilaterally. In successively older age groups, the prevalences of sigmoid plate dehiscence were 18.9%, 20.1%, 14.5%, and 12.7%, respectively. Respective average anteroposterior bony defect diameters were 3.7 ± 1.7, 3.0 ± 1.3, 3.1 ± 1.5, and 3.0 ± 1.1 mm. Respective average vertical bony defect diameters were 3.6 ± 2.3, 2.6 ± 1.2, 3.2 ± 1.5, and 3.0 ± 1.7 mm. The prevalence and extent of sigmoid plate dehiscence were not statistically different among the four age groups. Conclusions: The similar radiologic prevalence and extent of dehiscent sigmoid plates among the age groups suggest that the dehiscence is more commonly a congenital than an acquired condition

  2. From Point Defects to Plate Tectonic Faults

    OpenAIRE

    Regenauer-Lieb, Klaus; Hobbs, Bruce; Yuen, David; Ord, Alison; Zhang, Yanhua; Muhlhaus, Hans Bernd; Morra, Gabriele

    2007-01-01

    Abstract Understanding and explaining emergent constitutive laws in the multi-scale evolution from point defects, dislocations and two-dimensional defects to plate tectonic scales is an arduous challenge in condensed matter physics. The Earth appears to be the only planet known to have developed stable plate tectonics as a means to get rid of its heat. The emergence of plate tectonics out of mantle convection appears to rely intrinsically on the capacity to form extremely weak faul...

  3. Plate actuator vibration modes for levitation

    OpenAIRE

    Almurshedi, A; Atherton, M; C. Mares; Stolarski, T; Wei, B.; Wang, Y.

    2015-01-01

    The design of an aluminium or steel plate of various thicknesses for achieving levitation of a small aluminum disk is investigated by simulation using ANSYS. Each plate design is excited by an arrangement of four hard piezoelectric actuators driven with an AC voltage, which produces a centre displacement for generating a squeeze-film in the gap between the vibrating plate and the disk. Physical experiments show levitation conditions for one of the designs.

  4. 431K/CD vehicle number plates

    CERN Multimedia

    GS Department

    2009-01-01

    The Green Plates Service, which is responsible for issuing the 431K/CD vehicle number plates , wishes to apologise for the delay in processing applications over the past weeks. The delay is outside the Service’s control, as it is due to the recent introduction of new rules governing the vehicle registration process in France. Normal service will be resumed as soon as possible. Thank you for your understanding. GS-SEM-LS – Green Plates Service

  5. Plate Tectonics: A Paradigm under Threat.

    Science.gov (United States)

    Pratt, David

    2000-01-01

    Discusses the challenges confronting plate tectonics. Presents evidence that contradicts continental drift, seafloor spreading, and subduction. Reviews problems posed by vertical tectonic movements. (Contains 242 references.) (DDR)

  6. Unsteady Flow Between Two Oscillating Plates

    Directory of Open Access Journals (Sweden)

    Evelyn Chandra Sekharan

    1982-04-01

    Full Text Available The flow of an incompressible viscous fluid between two infinite harmonically oscillating plates is considered, when an oscillatory body force (having the same frequency as that of the plates is applied in the direction of motion problem, detailed analytical expressions for the velocity field of the fluid, volume flow rate and stress at the plates have been obtained. It is found that the fluid velocity oscillates in time with the same frequency as that of the plates or the body force, but with a phase difference.

  7. Locomotion of a flapping flexible plate

    Science.gov (United States)

    Hua, Ru-Nan; Zhu, Luoding; Lu, Xi-Yun

    2013-12-01

    The locomotion of a flapping flexible plate in a viscous incompressible stationary fluid is numerically studied by an immersed boundary-lattice Boltzmann method for the fluid and a finite element method for the plate. When the leading-edge of the flexible plate is forced to heave sinusoidally, the entire plate starts to move freely as a result of the fluid-structure interaction. Mechanisms underlying the dynamics of the plate are elucidated. Three distinct states of the plate motion are identified and can be described as forward, backward, and irregular. Which state to occur depends mainly on the heaving amplitude and the bending rigidity of the plate. In the forward motion regime, analysis of the dynamic behaviors of the flapping flexible plate indicates that a suitable degree of flexibility can improve the propulsive performance. Moreover, there exist two kinds of vortex streets in the downstream of the plate which are normal and deflected wake. Further the forward motion is compared with the flapping-based locomotion of swimming and flying animals. The results obtained in the present study are found to be consistent with the relevant observations and measurements and can provide some physical insights into the understanding of the propulsive mechanisms of swimming and flying animals.

  8. Wave propagation in metamaterial lattice sandwich plates

    Science.gov (United States)

    Fang, Xin; Wen, Jihong; Yin, Jianfei; Yu, Dianlong

    2016-04-01

    This paper designed a special acoustic metamaterial 3D Kagome lattice sandwich plate. Dispersion properties and vibration responses of both traditional plate and metamaterial plate are investigated based on FEA methods. The traditional plate does not have low-frequency complete bandgaps, but the metamaterial plate has low-frequency complete bandgap (at 620Hz) coming from the symmetrical local cantilever resonators. The bandgap frequency is approximate to the first-order natural frequency of the oscillator. Complex wave modes are analyzed. The dispersion curves of longitudinal waves exist in the flexural bandgap. The dispersion properties demonstrate the metamaterial design is advantageous to suppress the low-frequency flexural wave propagation in lattice sandwich plate. The flexural vibrations near the bandgap are also suppressed efficiently. The longitudinal excitation stimulates mainly longitudinal waves and lots of low-frequency flexural vibration modes are avoided. Furthermore, the free edge effects in metamaterial plate provide new method for damping optimizations. The influences of damping on vibrations of the metamaterial sandwich plate are studied. Damping has global influence on the wave propagation; stronger damping will induce more vibration attenuation. The results enlighten us damping and metamaterial design approaches can be unite in the sandwich plates to suppress the wave propagations.

  9. Strength of ship plates under combined loading

    DEFF Research Database (Denmark)

    Cui, Weiching; Wang, Yongjun; Pedersen, Preben Terndrup

    2000-01-01

    Strength of ship plates plays a significant role for the ultimate strength analysis of ship structures. In recent years several authors have proposed simplified methods to calculate the ultimate strength of unstiffened plates. The majority of these investigations deal with plates subjected to...... that the simplified method is able to determine the ultimate strength of unstiffened plates with imperfections in the form of welding induced residual stresses and geometric deflections subjected to combined loads. Comparisons with experimental results show that the procedure has sufficient accuracy...

  10. Perforated Plates as Passive Mitigation Systems

    Directory of Open Access Journals (Sweden)

    G.S. Langdon

    2008-03-01

    Full Text Available This paper presents the results of tests on fully-clamped circular plates subjected to blastloading directed down a tube. Four series of tests were performed. In one set of experiments,the blast wave was allowed to progress unhindered down the tube to impinge upon the plate,and in the other tests, perforated plates were placed in the path of the blast wave to hinderprogression down the tube, disrupting the blast and absorbing some of the kinetic energy.Results of the tests indicate that the perforated plates can be used as a form of passive mitigation.

  11. Development of Catalytic Cooking Plates

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden); Tena, Emmanuel; Berger, Marc [Gaz de France (France)

    2004-04-01

    Gas catalytic combustion for gas stoves or cooking plates (closed catalytic burner system with ceramic plates) is a very promising technique in terms of ease of cleaning, power modulation and emissions. Previous investigations show that wire mesh catalysts, prepared and supplied by Catator AB (CAT), seem to be very well suited for such applications. Beside significantly reducing the NOx-emissions, these catalysts offer important advantages such as good design flexibility, low pressure drop and high heat transfer capacity, where the latter leads to a quick thermal response. Prior to this project, Gaz de France (GdF) made a series of measurements with CAT's wire mesh catalysts in their gas cooking plates and compared the measured performance with similar results obtained with theirs cordierite monolith catalysts. Compared to the monolith catalyst, the wire mesh catalyst was found to enable very promising results with respect to both emission levels (<10 mg NO{sub x} /kWh, <5 mg CO/kWh) and life-time (>8000 h vs. 700 h at 200 kW/m{sup 2}). It was however established that the radiation and hence, the thermal efficiency of the cooking plate, was significantly less than is usually measured in combination with the monolith (15 % vs. 32 %). It was believed that the latter could be improved by developing new burner designs based on CAT's wire mesh concept. As a consequence, a collaboration project between GdF, CAT and the Swedish Gas Technology AB was created. This study reports on the design, the construction and the evaluation of new catalytic burners, based on CAT's wire mesh catalysts, used for the combustion of natural gas in gas cooking stoves. The evaluation of the burners was performed with respect to key factors such as thermal efficiency, emission quality and pressure drop, etc, by the use of theoretical simulations and experimental tests. Impacts of parameters such as the the wire mesh number, the wire mesh structure (planar or folded), the

  12. Tunable surface plasmon wave plates.

    Science.gov (United States)

    Djalalian-Assl, Amir; Cadusch, Jasper J; Balaur, Eugeniu; Aramesh, Morteza

    2016-07-01

    The highest resonant transmission through an array of holes perforated in metallic screens occurs when the dielectric constant of the substrate, the superstrate, and the hole are the same. Changes in the refractive index of the homogenous environment also produce the largest shift in resonances per refractive index unit. In this Letter, we first propose and apply a technique in realization of a freestanding bi-periodic array of holes perforated in a silver film. We then show both numerically and experimentally that shifts in (1,0) and (0,1) modes in response to changes in the refractive index of the surrounding dielectric provide a mechanism for realization of a miniaturized tunable quarter-wave plate that operates in an extraordinary optical transmission mode with a high throughput and a near unity state of circularly polarized light. PMID:27367123

  13. Factors Affecting the Morphology of Pb-Based Glass Frit Coated with Ag Material Prepared by Electroless Silver Plating

    Science.gov (United States)

    Huang, Bei; Gan, Weiping; Zhou, Jian; Li, Yingfen; Lin, Tao; Liu, Xiaogang

    2014-05-01

    Pb-based glass frit coated with nanosilver material for Si solar cell applications has been directly prepared by electroless silver plating. Activation of the glass frit was accomplished by using glycol, with the aim of reducing the silver ions to elemental silver on the surface of the glass frit. Electroless silver plating onto the glass frit was successfully realized using two kinds of electroless plating bath. However, the morphology of the composite powder greatly affected the modality, sheet resistance, series resistance, and photoelectric conversion efficiency of the conducting silver films. We found that the activation temperature affected the number and distribution of silver nanoparticles. Meanwhile, the average grain size of the silver particles and the silver content in the Pb-based glass frit coated with Ag material could be controlled by adjusting the pH value and loading capacity, respectively, during plating.

  14. Numerical analysis of grid plate melting after a severe accident in a Fast-Breeder Reactor (FBR)

    Indian Academy of Sciences (India)

    A Jasmin Sudha; K Velusamy

    2013-12-01

    Fast breeder reactors (FBRs) are provided with redundant and diverse plant protection systems with a very low failure probability (<10-6/reactor year), making core disruptive accident (CDA), a beyond design basis event (BDBE). Nevertheless, safety analysis is carried out even for such events with a view to mitigate their consequences by providing engineered safeguards like the in-vessel core catcher. During a CDA, a significant fraction of the hot molten fuel moves downwards and gets relocated to the lower plate of grid plate. The ability of this plate to resist or delay relocation of core melt further has been investigated by developing appropriate mathematical models and translating them into a computer code HEATRAN-1. The core melt is a time dependent volumetric heat source because of the radioactive decay of the fission products which it contains. The code solves the nonlinear heat conduction equation including phase change. The analysis reveals that if the bottom of grid plate is considered to be adiabatic, melt-through of grid plate (i.e., melting of the entire thickness of the plate) occurs between 800 s and 1000 s depending upon the initial conditions. Knowledge of this time estimate is essential for defining the initial thermal load on the core catcher plate. If heat transfer from the bottom of grid plate to the underlying sodium is taken into account, then melt-through does not take place, but the temperature of grid plate is high enough to cause creep failure.

  15. Development of a Titanium Plate for Mandibular Angle Fractures with a Bone Defect in the Lower Border: Finite Element Analysis and Mechanical Test

    Directory of Open Access Journals (Sweden)

    Douglas Rangel Goulart

    2015-09-01

    Full Text Available Objectives: The aim of the present study was to develop a plate to treat mandibular angle fractures using the finite element method and mechanical testing. Material and Methods: A three-dimensional model of a fractured mandible was generated using Rhinoceros 4.0 software. The models were exported to ANSYS®, in which a static application of displacement (3 mm was performed in the first molar region. Three groups were assessed according to the method of internal fixation (2 mm system: two non-locking plates; two locking plates and a new design locking plate. The computational model was transferred to an in vitro experiment with polyurethane mandibles. Each group contained five samples and was subjected to a linear loading test in a universal testing machine. Results: A balanced distribution of stress was associated with the new plate design. This plate modified the mechanical behavior of the fractured region, with less displacement between the fractured segments. In the mechanical test, the group with two locking plates exhibited greater resistance to the 3 mm displacement, with a statistically significant difference when compared with the new plate group (ANOVA, P = 0.016. Conclusions: The new plate exhibited a more balanced distribution of stress. However, the group with two locking plates exhibited greater mechanical resistance.

  16. Automation of large RPC electrodes surface resistivity measurement

    International Nuclear Information System (INIS)

    This article discusses methods for the automation of the surface resistivity measurement of large Resistive Plate Chamber electrodes. These methods consist of placing two probes that make contact on the surface of the electrodes. Fabrications of experimental setup, calculation of time, computer control and data acquisition method are given for the chosen method. (author)

  17. ANALYTICAL RELATIONS BETWEEN EIGENVALUES OF CIRCULAR PLATE BASED ON VARIOUS PLATE THEORIES

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the mathematical similarity of the axisymmetric eigenvalue problems of a circular plate between the classical plate theory(CPT), the first-order shear deformation plate theory(FPT) and the Reddy's third-order shear deformation plate theory(RPT), analytical relations between the eigenvalues of circular plate based on various plate theories are investigated. In the present paper, the eigenvalue problem is transformed to solve an algebra equation. Analytical relationships that are expressed explicitly between various theories are presented. Therefore, from these relationships one can easily obtain the exact RPT and FPT solutions of critical buckling load and natural frequencyfor a circular plate with CPT solutions. The relationships are useful for engineering application, and can be used to check the validity, convergence and accuracy of numerical results for the eigenvalue problem of plates.

  18. Microstructure and pitting corrosion of friction stir welded joints in 2219-O aluminum alloy thick plate

    Energy Technology Data Exchange (ETDEWEB)

    Xu Weifeng [School of Materials and Engineering, Northwestern Polytechnical University, Xi' an 710072 (China)], E-mail: xwf1982@mail.nwpu.edu.cn; Liu Jinhe [School of Materials and Engineering, Northwestern Polytechnical University, Xi' an 710072 (China)

    2009-11-15

    Effect of welding parameters on the microstructure and pitting corrosion of different positions along the thickness of weld nugget zone in friction stir welded 2219-O aluminum alloy plate was investigated using scanning electron microscopy (SEM), polarization experiment and electrochemical impedance tests (EIS). It was found that the material presents significant passivation and the top has best corrosion resistance compared to the bottom and base material. Corrosion resistance decreases with the increase of traverse speed from 60 to 100 mm/min at rotary speed 400 rpm. Corrosion resistance at rotary speed 600 rpm is lower than that at 500 rpm.

  19. Microstructure and pitting corrosion of friction stir welded joints in 2219-O aluminum alloy thick plate

    International Nuclear Information System (INIS)

    Effect of welding parameters on the microstructure and pitting corrosion of different positions along the thickness of weld nugget zone in friction stir welded 2219-O aluminum alloy plate was investigated using scanning electron microscopy (SEM), polarization experiment and electrochemical impedance tests (EIS). It was found that the material presents significant passivation and the top has best corrosion resistance compared to the bottom and base material. Corrosion resistance decreases with the increase of traverse speed from 60 to 100 mm/min at rotary speed 400 rpm. Corrosion resistance at rotary speed 600 rpm is lower than that at 500 rpm.

  20. Thickness dependence of the Casimir force between a magnetodielectric plate and a diamagnetic plate

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Norio [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2201 (Japan)

    2011-11-15

    This paper examines the repulsive Casimir force between a magnetodielectric plate, with static permeability greater than static permittivity, and a diamagnetic plate. As the thickness of the magnetodielectric plate is decreased, the attractive component of the Casimir force decreases more than the repulsive one. This effect makes the net Casimir force repulsive, and a larger repulsive Casimir force is generated compared to the Casimir force between the plates with infinite thickness.